Luận Văn Xác Định Tính Nhạy Của Một Số Loài Thuốc Kháng Sinh Đối Với...

8/11/2019 Lun Vn Xc nh Tnh Nhy Ca Mt S Loi Thuc Khng Sinh i Vi Edwardsiella Sp V Aeromonas Sp Gy B

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TRNG I HC TY KHOA SINH HC NG DNG

SOosBsocs

LUN VN TT NGHIP I HC

CHUYN NGNH NUI TRNG THY SN

M S: 304

XC NH TNH NHY CA MT SLOITHUC KHNG SINH I VIdwardsiellsp

VAeromonas spGY BNH TRN C TRATI CN TH VAN GIANG

Sinh vin thc hin

NGUYN THMINH TRANG MSSV:06803052 LP: NTTS KI

Cn Th, 2010


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Cn bhng d n

Ths. LM PHC NHN KS.PHM THANH HNG

Sinh vin thc hin

NGUYN THMINH TRANG

MSSV: 06803052 LP: NTTSK1

TRNG I HC TY KHOA SINH HC NG DNG

LUN VN TT NGHIP I HC

CHUYN NGNH NUI TRNG THY SN

M S: 304

XC NH TNH NHY CA MT SLOITHUC KHNG SINH I VIdwardsiellsp

VAeromonassp GY BNH TRN C TRATI CN TH VAN GIANG

Cn Th, 2010


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LI CM T

3

Sau 3 thng thc tp tthng 03-06 nm 2010 ti Chi Cc Thy Sn thnh phcn Th,

168 Hai B Trng, Phng Tn An-Qun Ninh Kiu-TP. cn Th, p dng nhng kin

thc hc kt hcrp vi kinh nghim thc t, nay lun vn c chnh sa v hon

thnh.

Em xin by tlng bit n su sc i vi thy Lm Phc Nhn v c Phm Thanh Hng

phng th nghim Chi Cc Thy Sn TP. cn Th tn tnh hng dn v chdy cho em

sut thi gian lm ti.

Em xin chn thnh cm n qu thy c - Khoa Sinh Hc ng Dng - Trng i Hc Ty

tn tnh dy bo, truyn t cho em nhng kin thc qy bu trong nhng nm hcva qua, to dng hnh trang em bc vo cuc sng sau ny.

Chn thnh cm n cha mv ngi thn lun bn cnh ng h, ng vin v ng gp

kin trong sut thi gian qua.Xin cm n tt cc ch, anh chtrong Chi Cc Thy Sn tn tnh chdn, gip vng gp kin bch em hon thnh thc tp tt nghip.

Chn thnh cm n tt ccc bn trong lp NTTS KI trong thi gian qua lun ng h,ng vin hon thnh thc tp tt nghip.

Cui cng em xin chc qu thy c - Khoa Sinh Hc ng Dng - Trng i Hc Ty vui, khe, cng tc tt v khng ngng con ng cng hin cho snghip gio dc.

Vi shiu bit cn hn hp v thu thp ti liu cn hn chnn bo co tt nghip khng

trnh khi ssai st. Knh mong c sng gp kin ca qu thy c v cc bn.

Em xin chn thnh cm n v ghi nh!


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TM TTVi khunEdwardsiellasp vAeromonassp l hai dng vi khun gy bnh phbin trn

c tra (Pangasianodon hypophthalmus)hin nay. Nn vic sdng khng sinh thng

xuyn iu trbnh dn n tnh trng khng thuc ca vi khun. Mc tiu ca ti l

Xc nh c loi khng sinh cn nhy vi vi khunEdwardsiellasp vAeromonassp

vic iu trt hiu qucao. ti thc hin khng sinh ln 2 vi khun trn, vi

13 loi khng sinh trn 10 chng mi dng vi khun. Vi khun c phn lp tc trabnh mgan v xut huyt ti cn Th v An Giang qu 2 nm 2010.

Kt qu phn lp c vi khunEdvvardsiellasp vAeromonassp. Kt qukhng sinh

cho thy: cc khng sinh c t l% nhy vi vi khunEdwardsiellasp trn 75% l:

ampicillin, amoxicillin, ciproAoxacin. Cc khng sinh c t l % nhy vi vi khun

Aeromonassp trn 75% l: enroloxacin, ciproloxacin, norloxacin, oloxacin.

Ngoi ra, ti xc nh c cc loi khng sinh nhy ng thi vi c2 vi khun

Edwardsielasp vAeromonassp, cn Th l: ciproloxacin, An Giang l: oAoxacin,norAoxacin, ciproloxacin v florfenicol. Cc khng sinh khng viEdwardsiellasp vi t

l% khng >50% l: colistin, doxycyclin, tetracyclin, enroloxacin, florfenicol, kanmycin

v riamycin. Cc khng sinh khng vi Aeromonas sp vi t l % khng >50% l:ampicillin, amoxicillin, cealexin, colistin, tetracyclin, kanamycin v riamycin.

Tkha:Edwardsiella, Aeromonas, khng sinh.


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LI CAM KT

5

Ti xin cam kt lun vn ny c hon thnh da trn cc kt qunghin cu ca ti vcc kt quca nghin cu ny cha c dng cho bt clun vn cng cp no khc.

Cn Th, ngy 3 thng 08 nm

2010

Nguyn ThMinh TrangMC LC

LI CM T.......................................................................................................... i

TM TT .............................................................................................................. ii

MC LC ............................................................................................................. iv

DANH SCH BNG ................................................................ ............................ vi

DANH SCH HNH............................................................................................. vii

DANH SCH TVIT TT ................................................................................ ix

CHNG 1............................................................................................................ 1

T VN ........................................................................................................ 1

1.1 Gii thiu .................................................................................................... 1

1.2 Mc tiu ti............................................................................................. 2

1.3 Ni dung ti ............................................................................................ 2

CHNG II........................................................................................................... 3

LC KHO TI LIU ........................................................................................ 3

2.1 c im sinh hc c tra.............................................................................. 3

2.1.1 Hthng phn loi .............................................................................. 3

2.1.2 c im hnh thi .............................................................................. 3

2.1.3 Phn b............................................................................................... 3

2.1.4 c im dinh dng ......................................................................... 3

2.1.5 c im sinh trng ......................................................................... 4


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2.1.6 c im sinh sn ............................................................................... 4

2.2 Tng quan vvi khunEdwardsiellasp vAeromonassp ............................. 4

2.2.1 Yi khunEdwardsieasp ................................................................... 4

2.2.2 Vi khunAeromonassp ...................................................................... 52.3 Tnh hnh nghin cu bnh do vi khunEdwardsieasp vAeromonassp...6

2.3.1 Nghin cu trn thgii ....................................................................... 6

2.3.2 Nghin cu Vit Nam ....................................................................... 6

2.4 Tng quan vcc loi khng sinh ................................................................. 7

2.4.1 nh ngha .......................................................................................... 7

2.4.2 Nguyn tc sdng khng sinh .......................................................... 7

2.4.3 Cc loi khng sinh phbin hin nay ................................................ 7


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2.5 Cc nghin cu vthuc khng sinh trong nui trng thy sn ............ 18

CHNG III....................................................................................................... 20

VT LIU V PHNG PHP NGHIN cu ............................................... 20

3.1 Vt liu nghin cu ..................................................................................... 20

3.1.1 Thi gian v a im nghin cu ..................................................... 203.1.2 Vt liu nghin cu ............................................................................ 20

3.1.3 Thit b, dng cv ha cht.............................................................. 20

3.2 Phng php nghin cu ............................................................................ 20

3.2.1 i tng nghin cu ......................................................................... 20

3.2.2 Phng php thu mu ........................................................................ 20

3.2.3 Phng php phn lp v nh danh vi khun .................................... 21

3.2.4 Phng php lm khng sinh ......................................................... 22

CHNG IV................................ ....................................................................... 24KT QUV THO LUN.............................................................................. 24

4.1 Ket quphn lp v nh danh vi khunEdyvardsiellasp vAeromonassp ............................................................................................... 24

4.2 Kt qukhng sinh ................................................................................ 26

4.2.1 Kt qukhng sinh ca vi khunEdwardsieasp ti 2 tnh cnTh v An Giang.................................................................................. 27

4.2.2 Kt qukhng sinh ca vi khunAeromonassp ti 2 tnh cnTh v An Giang ................................................................................. 31

4.2.3 Kho st tnh nhy ca vi khunEdwardsiellasp vAeromonassp2 tnh Cn Th v An Giang.............................................................. 34

CHNG V......................................................................................................... 37

KT LUN V XUT ................................................................................. 37

5.1 Kt lun ..................................................................................................... 37

5.2 xut ....................................................................................................... 37

TI LIU THAM KHO ................................................................................... 38

PHLC.............................................................................................................. A


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DANH SCH BNG

8

Trang

Bng 4.1: Kt qukim tra cc c im sinh ha ca vi khunEdwardsiellaspyAeromonassp ....................................................... 25

Bng 4.2: Tltnh nhy ca 10 chng vi khunEdwardsiellasp vi 13loi khng sinh ................................................................................. 28

Bng 4.3: Tltnh nhy ca 10 chng vi khunAeromonassp vi 13 loikhng sinh ........................................................................................ 32

Trang

Hnh 2.1: Hnh dng bn ngoi ca c tra ......................................................... 3

Hnh 2.2: Vi khunAeromonas hydrophlac mt tim mao ............................. 5

Hnh 2.3: Cng thc cu to ampicillin ............................................................... 8

Hnh 2.4: M hnh phn tampicillin ................................................................. 8Hnh 2.5: Cng thc cu to amoxcillin ............................................................... 9

Hnh 2.6: M hnh phn tamoxcillin ................................................................. 9

Hnh 2.7: Cng thc cu to cefalexin ............................................................... 10

Hnh 2.8: Cng thc cu to colistin .................................................................. 10

Hnh 2.9: Cng thc cu to doxycyclin ............................................................ 11

Hnh 2.10: M hnh phn tdoxycyclin ............................................................ 11

Hnh 2.11: Cng thc cu to tetracylin ............................................................ 12Hnh 2.12: Cng thc cu to enrofloxacin ....................................................... 13

Hnh 2.13: Cng thc cu to ciprofloxacin ...................................................... 14

Hnh 2.14: M hnh phn tciprofloxacin ........................................................ 14

Hnh 2.15: Cng thc cu to norfoxacin .......................................................... 15

Hnh 2.16: Cng thc cu to ooxacin ............................................................. 15

Hnh 2.17: Cng thc co to florfenicol ........................................................... 16

Hnh 2.18: Cng thc ha hc kanamycin ......................................................... 17

Hnh 2.19: Cng thc cu to rifamycin ............................................................ 18

Hnh 3.1: Quy trnh phn lp vi khunEdyvardsiellasp vAeromonassp ....... 21

Hnh 4.1: Ni tng c tra bbnh mgan .......................................................... 24

Hnh 4.2: C tra bbnh xut huyt .................................................................. 24


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DANH SCH HNH

9

Hnh 4.3: Ni tng c tra bxut huyt .............................................................. 24

Hnh 4.4: Kt qutch rng vi khunEdwardsieisp ..................................... 25

Hnh 4.5: Kt qutch rng vi khunAeromonassp ........................................ 25Hnh 4.6: Hnh nhum Gram ca vi khunEdwardsieisp (100X)................. 25

Hnh 4.7: Hnh nhum Gram ca vi khunAeromonassp (100X) .................... 25


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Hnh 4.8: Vi khunAeromonassp mi thc hin test 0/F .................................. 26

Hnh 4.9: Vi khunAeromonassp cho phn ng ln men sau 24 gi................ 26

Hnh 4.10: Kt qukhng sinh chngEdwardsiellasp sau 48 gi............... 27Hnh 4.11: ng knh trung bnh v trng ca thuc khng sinh i vi

Edwardsieasp ti cn Th v An Giang....................................... 30

Hnh 4.12: Kt qukhng sinh ca chngAeromonassp sau 24 gi........... 31

Hnh 4.13: ng knh trung bnh v trng ca thuc khng sinh i

viEdwardseUasp ti cn Th v An Giang................................ 33

Hnh 4.14: Phn trm nhy ca vi khunEdwardsielasp vAeromonassp..34

Hnh 4.15: ng knh trung bnh v trng ca thuc khng sinh iviAeromonassp vEdwardsellasp ti An Giang ........................ 35

DANH SCH TVIT TT1. BSCL: ng Bng Sng Cu Long

2. MHA: Mueller hinton agar

3. TSA: Trypic soy agar

4. Ampicillin (AM)

5. Amoxicillin (AMX)

6. Cealexin (CN)

7. Colistin (CS)

8. Doxycyclin (DO)

9. Tetracyclin (TE)

10. Enroloxacin (ENR)

11. CiproAoxacin (CIP)

12. Norloxacin (NOR)

13. Oloxacin (OF)

14. Florfenicol (FFC)

15. Kanamycin (K)

16. Riamycin (RA)


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17. EIA:Edvvardsiell ictaluriagar

CHNG I

T VN 1.1 Gii thiu

C tra Pangasianodon hypophthalmus)l loi c trn nc ngt c nui phbin

ng Bng Sng Cu Long, c bit cc tnh An Giang, ng Thp, cn Th... Trong

vi nm trli y, phong tro nui c tra xut khu ng Bng Sng Cu Long tng

rt nhanh, em vcho t nc ngun ngoi trt ln. Tnh n ngy 14/08/2009, din

tch thnui c tra ca cc tnh BSCL l 5.154 ha tng 2,7 ln so vi u nm 2009; tp

trung nhiu nht 3 tnh l: ng Thp 1.489 ha, cn Th 1.110 ha v An Giang 1.023

ha, chim khong 70,3% din tch thnui ton vng. Cng n gia thng 08/2009, sn

lng c tra thu hoch ton vng l 457.000 tn, gp 8,2 ln so vi u nm, sn lng cthu hoch trong 8 thng u nm tng lin tc vi mc tng bnh qun l 13,5%/thng.

Tng sn lng c tra xut khu 8 thng qua l 325.920 tn, kim ngch xut khu t hn737 triu USD.

Khi nhng li ch do nghnui thy sn mang li ngy cng cao, th nghnui ngy cng

c thm canh ha. Tuy nhin, khi nghnui c thm canh ha vi mt cao th

vn dch bnh xy ra thng xuyn hn v thit hi cng nhiu hn (ng ThHong

Oanh v csv,2004). Trong scc bnh thng gp trn c tra nh: m , trng da, ph

u ph mt, xut huyt, bnh do k sinh trng ngoi k sinh... th bnh xut huyt v

bnh m trng trn gan gy thit hi nghim trng trong nui c tra thm canh. Theo

Ferguson v csv(2001) th bnh gan thn mc pht hin ln u tin ti Vit Nam

1998, khi c nhim bnh, tlcht tng cao 10-90% ty thuc vo cch qun l v cc

nui (trch dn bi TThanh Dung v csv,2004). Tng ti vi bnh xut huyt trn

c tra cng gy ra tlcht rt cao t60-70% nu iu trkhng kp thi (Nguyn Chnh,2005).

Hin nay, vic sdng khng sinh trong iu trbnh vi khun trn ng vt thy sn

mt snc l kh ln nh: Trung Quc 1.500 tn, Nht Bn 1.100 tn, Thi Lan 420

tn, n 400 tn... Vit Nam 50 tn/nm (Mudd, T., 2003. Trch dn bi

Tangtrongpos, J., 2005). Hin nay trn thtrng c nhiu loi khng sinh trbnh vi

khun trn c tra, nn ngi dn sdng trn lan cc loi khng sinh v khng tun th

nghim cc quy nh, dn n tnh trng lm dng thuc, gim sc khng ca vt nui

v to ra nhng dng vi khun khng thuc. Hu qu gy thit hi vkinh t, tn km

nhiu chi ph cho ngi nui do vic diu trbnh km hiu qu. V th, cn xc nh li

cc loi khng sinh cn nhy vi vi khun, gip ngi dn la chn ng loi khng


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sinh, gp phn hn chthit hi do vi khun

Edvvardsiella spvAeromonas sptrn c tra gy ra, gim bt ri ro cho ngi nui l rtcn thit.

Chnh v vy, ti: Xc nh tnh nhy ca mt sloi thuc khng sinh i viEdwardsiellasp vAeromonassp gy bnh trn c tra ti cn Tho v An Giangc thc hin.

1.2 Mc tiu ti

Dng phng php khng sinh nhm xc nh c cc loi khng sinh cn nhy vi

vi khun vic iu trt hiu qucao. ti gp phn gim chi ph ha cht, gim

nhim mi trng do t dng thuc khng sinh, c c iu trsm lm gim tlhaoht trn c, n nh nng sut v cht lng.

1.3 Ni dung ti

Phn lp vi khunEdyvardsiellasp vAeromonassp tgan, thn v ttng trn c trabnh.

Lp khng sinh ca hai loi vi khun trn i vi 13 loi thuc khng sinh.


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CHNG II

Lc KHO TI LIU

2.1 c im sinh hc c tra (Pangasianodon hypophihamus)

2.1.1

Hthng Phn loiTheo hthng phn loi ca Rainboth, W.J, 1996

BSiluriormes

HPangasiidae (Bleeker, 1858)

GingPangasianodon(Rainboth, 1996)

LoiPangasianodon hypophthalmus(Sauvage, 1878)

(trch dn bi Nguyn Vn Thng, 2008)

Hnh 2.1: Hnh dng bn ngoi ca c tra {Pangasianodon hypophthalmus)

2.1.2 c im hnh thiC tra l c da trn, thn di, dp ngang, lng xm en, bng hi bc, ming rng c hai

i ru di, u nhva phi, mt tng i to. Vy lng cao, c mt gai cng c rng

ca. Vy ngc c ngnh, bng c 8 tia phn nhnh, trong khi cc loi khc c 6 tia (PhmVn Khnh, 1996).

2.1.3 Phn B

C tra c tn khoa hcPangasianodon hypophthalmustrc y c tn lp. micronemus

hay p. sutchi, phn b lu vc sng Mekong, c mt c 4 nc Lo, Vit Nam,

Campuchia v Thi Lan. C c khnng sng tt trong iu kin ao t nc ng, nhiu

cht hu c, oxy ha tan thp v c thnui vi mt cao (Nguyn Vn Kim, 2004).2.1.4 c im dinh dng

C tra l loi c n tp. Trong tnhin, c n c mn b hu c, rcy thy sinh, rau

qu, tm, tp, cua, cn trng, c v c... C nui trong ao sdng nhiu loi thc n khc

nhau nh: Thc n tch, thc n cng nghip, cm, tm, rau mung... Thc n c ngun

gc ng vt gip c ln nhanh hom (Nguyn Vn Kim, 2004).


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2.1.5 c im sinh trng

C tra c tc tng trng tomg i nhanh, cn nhc tng nhanh chiu di, sau 1 nm

c t trng lng 1-1,5 kg/con, vsau c tng trng nhanh hom, c tht ti 25 kg c10 nm tui (Nguyn Vn Kim, 2004).

2.1.6 c im sinh sn

C tra khng trong ao nui, c c tp tnh di c tnhin trn nhng khc sng c

iu kin sinh thi ph hp thuc a phn Campuchia v Thi Lan, c cng khng c bi

t nhin Vit Nam. C tra Campuchia, c bt theo dng nc vVit Nam(Nguyn Vn Kim, 2004).

Tui thnh thc ca c tra trn sng Mekong 3-4 nm tui. C tra c tp tnh di c ngc

dng i , ma vsinh sn ca c trong tnhin bt u tthng 5-7 m lch hng nm.

Trng lng c thnh thc ln u t2,5-3 kg (Nguyn Vn Kim, 2004).

2.2 Tng quan vvi khunEchvardsiela spvAeromonas sp

2.2.1 Vi khunEdwardsella sp

Ngnh: Proteobacteria

Lp: Gammaproteobacteria

B: Enterobacteriales

H: Enterobacteriaceae

Ging:Edwardsiella

Theo Crumlish v csv (2002), bnh mgan (bnh m trng trn gan, thn) trn c tra, do

nhm vi khunE. ictalurigy ra (trch dn bi TThanh Dung v csv,2005).c im sinh l, sinh ha

Vi khun Edvvardsiella ictaluri l vi khun Gram m, hnh que mnh, kch thc 1 X

2-3pm, khng sinh bo t, l vi khun ym kh ty tin. Cho phn ng oxidase m tnh,

oxy ha m v ln men trong mi trng OZF glucose. Chuyn ng nhvnh tim mao.Thng gp hai loi:E. tarda v E. ictaluri(Bi Quang T, 2006).

E. tarda l tc nhn gy bnh nhim khun c nc m, c bit l c khng vy.E.

ictalurigy bnh nhim khun trong cc c quan ni tng gan, ty, thn ca c khng vy.

Loi E. tardahu ht khng ln men cc loi ng nhng c mt vi chng ln men

ng kh nhanh (Bi Quang T, 2006).E. tardapht trin tt nhit 37c trong khi E. ctaurpht trin tt 28c v pht

trin yu 37c. Cc c im sinh ha ca vi khunE. ctauricho hu ht cc phn ng

m tnh chi c 2 phn ng dng tnh l Lysine v Ghi so se. Khi so snh cc chtiu sinh

ha ca vi khunE. ictaluriviE. tardacho thy vi khunE. ictauricho phn ng Indole

v H2S m tnh, trong khi E. tardacho phn ng dng tnh (TThanh Dung v csv,


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2005).

ng ly truyn

E. ictaluricthnhim cho c bng hai ng khc nhau, vi khun trong nc cthqua

ng mi ca c xm nhp vo c quan khu gic v di chuyn vo dy thn knh khu

gic, sau vo no, bnh lan rng tmng no n sv da,E. ictaluri cng cthxmnhim qua ng tiu ho qua nim mc rut vo mu gy nhim trng mu, bng ng

ny th vkhun vo mao mch trong biu b gy hoi tv mt sc tca da, c da trncn nhimE. ictalurqua ng ming gy nhim khun rut, bnh pht trin gy vim

rut, vim gan v vim cu thn trong vng 2 tun sau khi nhim bnh (Thanh Dung v

csv,2005).

2.2.2 VkhunAeromonas sp

Ngnh: Proteobacteria

Lp: Gammaproteobacteria

B: Aeromonadales

H: Aeromonadaceae

Ging:Aeromonas

Hnh 2.2: Vi khunAeromonas hydrophilac mt tim mao.(Anh knh hin vi in t)

Trong gingAeromonasc hai nhm:

Nhm 1:Aeromonaskhng di ng (A. samonicida) gy bnh nc lnh.

Nhm 2: L cc loiAeromonasdi ng, bao gmA. hydrophila, A. caviae, A. sobria.

c tnh chung ca ba loi vi khun ny l di ng nhc 1 tim mao. Vi khun Gram m

dng hnh que ngn, hai u trn, kch thc 0,5 X l,0-l,5fim. Vi khun ym kh ty tin,

cytochrom oxidase domg tnh, kh nitrate, khng mn cm vi thuc thVibriostat

0/129... Cc vi khunAeromonasdi ng u c phn lp tc nc ngt nhim bnh,

thng gp nht l loiA. hydrophila(Bi Quang T, 2006).

2.3 Tnh hnh nghin cu bnh do vi khunEdwardsella spvAeromonas sp


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2.3.1 Nghin cu trn thgii

Vi khunE. ictaluric Hawke (1979) phn lp u tin trn c Nheo nui ti chu M

lctalurus punctatus)v c xc nh l nguyn nhn gy bnh ESC (Enteric septicaemia

of catish) (trch dn bi Hunh Ch Thanh, 2007).

Theo Plumb v Bowser (1983) cho rng vi khunE. ictalurikhng chnhy cm trn cnheo Mm cn c thly nhim trn c r phi khi tim vi khun (trch dn bi Phan ThMHnh, 2004).

Boonyaratpalin (1985) cng pht hin vi khunE. ictaluri trn c tr trng (Clariasbatrachus)v trong mi trng nc Thi Lan J. Kasomchandra 1987 (trch dn biPhan ThMHnh, 2004).

Theo Tanasomvvang v Saitanu (1979) vi khunA. hydrophilacn c xc nh l tcnhn gy bnh xut huyt cho c basa bmnui trong b g(trch dn bi Ng MinhDung, 2007).

A. hydrophilagy bnh llot cho c ti Java-Indonesia v gy t ltvong t80- 90%(Angka, 1990), Saitanu v Wongsawang (1982) tm thy vi khunA. hydrophila gy bnh

xut huyt do nhim trng mu trn c tra (trch dn bi Ng Minh Dung, 2007)

Bnh xut huyt v hoi t c tm thy c tr trng ging (Clarias batrachus) do

nhim vi khunA. hydrophila.Vi khunA. hydrophilacn tm thy trn bnh phm c tr

(Claras sp)(trch dn bi Trn Anh Dng, 2005).

2.3.2 Nghin cu Vit Nam

Theo Ferguson v csv(2001), bnh mgan c ghi nhn u tin BSCL vo cui

nm 1998 trn c tra nui v c tn Bacillary Necrosis of Pangacisus (BNP) (trch dn bi

TThanh Dung v csv,2004).Theo TThanh Dung v csv(2001) phn lp c 108 dng vi khunE. ictalur gybnh trn c tra. Cedric Komar v Zilong Tan (2003) cng phn lp vi khunE. ictauritrn c tra nui b Vit Nam vi du hiu bnh c nhiu m trng trn gan (trch dnbi TThanh Dung, 2005).

Cedrie Komar v csv(2003) cng phn lp vi khunE. ictaluritrn c tra nui b

Vit Nam vi du hiu bnh m trng hn gan, thn, ttng v ty ca c nheo M(trchdn bi Phan ThMHnh, 2004).

Bnh m cn gi l bnh xut huyt, bnh nhim trng mu, bnh si... l do vi khun

A. hydrophila(theo Bergey 1957, trch dn bi TThanh Dung v csv,2005).

2.4 Tng quan vcc loi khng sinh

2.4.1 nh ngha

Khng sinh l nhng cht c tc ng chng li ssng ca vi khun, ngn nga vi khun

nhn ln bng cch tc ng mc phn t, hoc tc ng vo mt hay nhiu giai on

chuyn ha cn thit ca i sng vi khun hoc tc ng vo scn bng l ha (T


17/5217

Thanh Dung v csv,2005).

Trong y hc, th y v nui trng thusn, ngi ta dng khng sinh trcc bnh nhim

khun v em li hiu quiu trrt cao, nu dng ng thuc, ng liu, ng thi

im. Tuy vy, dng khng sinh cng c mt tri, c thnh hng xu n ng vt s

dng n v cng c nhng tc ng khng nhti mi trng sinh thi. Nu dng khng

sinh ty tin v thiu hiu bit c thlm gim sc khng ca vt nui vi cc loi mm

bnh.

2.4.2 Nguyn tc sdng khng sinh

Chsdng khng sinh khi c nhim vi khun.

Phi chn ng khng sinh v dng thuc thch hp.

Phi sdng khng sinh ng liu, ng thi gian quy nh.

Bit cch phi hp khng sinh iu trv khng sinh dphng.

Chsdng khng sinh c php sdng trong nui trng thy sn.

(TThanh Dung v csv,2005)

2.4.3 Cc loi khng sinh phbin hin nay

2.4.3.1 Nhm beta-lactamin

L nhm khng sinh c tc dng dit khun c phkhng khun hp, chyu tc dng

trn vi khun Gram dng v mt t vi khun Gram m. Do mng tbo ca vi khun

Gram m c tllipit cao nn n knc, cn nhm P-lactamin phi khuych


18/5218

Hnh 2.4: M hnh phn t

ampicillin

tn qua cc ng dn protein nm trn bmt mng (trch dn bi Trn Duy Phng, 2009).

i din ca nhm ny thng c dng trong thy sn l: ampicillin, amoxicillin.

Ampicillin (AM)

Hnh 2.3: Cng thc cu toampicillin

Tn chung quc t: Ampicillin Cng thc ha hc:Ci6H19N304S Tn khc:

Aminobenzylpenicillin

Ampicillin l khng sinh bn tng hcrp thuc hbeta-lactamines, nhm penicillin type A,

c tnh thp, phkhng khun rng.

Tng tpenicilin, ampicillin tc dng vo qu trnh nhn ln ca vi khun, c chs

tng hp mucopeptid ca mng tbo vi khun (Dc th, 2002).

Ampicillin l khng sinh phrng c tc dng trn cu khun Gram dng v Gram m:

Streptoccoccus, Pneumococcusv Staphylococcus.Ampicillin c tc dng tt trn mt s

chng vi khun Gram m ng rut nh:E. coli.Ampicillin khng tc dng trn mt schng vi khun Gram m nh:Pseudomonas(Dc th, 2002).

Ampicillin c thxm nhp Gram dng v mt sGram vi khun tiu cc. N khc vi

penicillin chbi shin din ca mt nhm amin l nhm amin gip thuc xm nhp

vo mng ngoi ca vi khun Gram m. Thuc c tnh acid, khi dng mui rt dtan

trong nc. Khi c dng iu tr, thuc phn tn u trong c thnhng tp trung

nhiu gan, thn, mt phn nhngm vo dch no ty. Thuc c thi trqua thn

dng nguyn thy ra mi trng ngoi nn rt dgy ra hin tng khng vi loi thuc

ny ca vi khun (trch dn bi Trn Duy Phng, 2009).


19/5219

HO

NU;

CO H

Hnh 2.5: Cng thc cu toamoxicillin

Hnh 2.6: M hnh phn tamoxicillin

Amoxicillin (AMX)

Tn chung quc t: Amoxicillin

Cng thc ha hc:

C16H19N3O5S

Tn ha hc: (2S,5/?,6/?)-6-{[(2/?)-2-amino-2-(4-hydroxyphenyl)-acetyl]amino}-3,3-dimethyl-7-oxo-4-thia-l-azabicyclo[3.2.0]heptane-2-carboxylic acid.

Amoxicillin (INN) trc y l amoxicillin (BAN), vit tt AMOX, l mt quang ph,bacteriolytic, P-Lactam khng sinh dng iu trnhim trng do vi khun.

Amoxicillin l aminopenicilin, bn trong mi trng acid, c ph tc dng rng hom

benzylpenicilin, c bit c tc dng chng trc khun Gram m.

Tng tnh cc penicilin khc, amoxicillin tc dng dit khun, do c chsinh tnghcrp mucopeptid ca thnh tbo vi khun.

Amoxicillin c hot tnh vi phn ln cc loi vi khun Gram m v Gram dng nh:

Lin cu khun, tcu khun khng to penicilinase,E. coi...

Cng nh ampicillin, amoxicillin khng c hot tnh vi nhng vi khun tit penicilinase,c bit cc tcu khng methicilin, tt ccc chngPseudomonasv phn ln cc chng

KlebsiellavEnterobacter.

Phtc dng ca amoxicillin c thrng hn khi dng ng thi vi sulbactam v acidclavulanic, mt cht c chbeta-lactamase. c thng boE. colikhng camoxicillinphi hp vi acid clavulanic (16,8%) (Dc th, 2002).


20/5220

2.4.3.2 Nhm

Cefalosporin Cefalexin

(CN)

Hnh 2.7: Cng thc cu to cealexin

Tn chung quc t: Cealexin

Cng thc ha hc:

C16H17N3O4S

Tn ha hc: (6i?,7/?)-7-{[(2/?)-2-amino-2-phenylacetyl]amino}- 3-methyl-8-oxo-5-

thia-l-azabicyclo[4.2.0]oct-2-ene- 2-carboxylic acid

Cealexin l khng sinh nhm cephalosporin thh1, c tc dng dit khun bng cch c

chtng hp vtbo vi khun.

Cefalexin bn vng vi enzim penicilinase ca vi khun Staphyococcus,do c tc

dng vi c cc chng Staphylococcus aureus tit penicilinase khng penicilin (hayampicillin).

Cealexin cng c tc dng trn a scc E. colikhng ampicillin. Hu ht cc chng

Enterococcus(Streptococcus aecalis) v mt t chng Staphylococcuskhng cealexin.

Mt schng: Enterobacter spp, Pseudomonas aeruginosa, Bacteroides spp,cng thy

c khng thuc. Ceelexin c tc dng viE. coli,c tlkhng cealexin khong 50%,

Enterobacterctlkhng khong 23%,Pseudomonas aeruginosac tlkhng khong20% (Dc th, 2002).

2.4.3.3 Nhm Polymyxin

Colistin (CS)


21/5221

Hnh 2.8: Cng thc cu to colistin


22/5222

Hnh 2.10: M hnh phn tdoxycyclin

Tn chung quc t: Colistin Cng

thc ha hc: C52H98Ni6Oi3

Tn ha hc: A^-(4-amino-l -(1-(4-amino-1 -0X0-1 -(3,12,23-tris(2-aminoethyl)- 20-(l-

hydroxyethyl)-6,9-diisobutyl-2,5,8,11,14,19,22-heptaoxo-1,4,7,10,13,18-

hexaazacyclotricosan-15-ylamino)butan-2-ylamino)-3-hydroxybutan-2-ylamino)-1 -oxobutan-2-yl)-^V,5-dimethylheptanamide

Colistin thng dng iu trnhng trng hp nhim khun nng do vi khun Gram

m, c bit l cc trng hp nhim khunPseudomonas aeruginosa(Dc th, 2002).

2.4.3.4 Nhm Tetracyclin

L thuc c chvi khun nng thp v dit khun nng cao. N phthuc vo

mn cm ca vi khun i vi thuc. y l nhm khng sinh c phhot rt rng. Tc

dng ci vi nhm vi khun Gram m v Gram dng nhng vi khun Gram dng

mn cm vi thuc hn l Gram

m, virus, k sinh trng (trch dn

bi Trn Duy Phng, 2009).

i din ca nhm ny thngc dng trong thy sn l

doxycyclin, tetracylin...

Doxycyclin (DO)

Hnh 2.9: Cng thc cu todoxycyclin

Tn chung quc t: Doxycyclin

Cng thc ha hc: C22H24N208

Tn ha hc: (4S,4a/?,5,5a/?,6/?,12aS')-4-(dimethylamino)-3,5,10,12,12a-

pentahydroxy-6-methyl-1,11 -dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2-

carboxamide


23/5223

Doxycyclin l khng sinh phrng tc ng ln nhiu vi khun Gram m v Gram dng.


24/5224

Tc ng khng khun ca doxycyclin c chvi khun tng hp protein do gn vo tiu

om v30S v c thcvi 50S ca ribosom vi khun nhy cm, thuc cng c thgythay i mng bo tomg.

Doxycyclin c phm vi khng khun rng vi vi khun a kh v kkh Gram domg v

Gram m, v c vi mt s vi sinh vt khng thuc tc dng vi thnh tbo, nh:

Rickettsia, Coxiella bumetii, Mycoplasma pneumoniae, Chlamydia spp, Legionella spp,

Ureaplasma, mt sMycobarteriumkhng in hnh, v Plasmodium spp (Dc th,2002).

Tetracyclin (TE)

Hnh 2.11: Cng thc co to tetracyclin

Tn chung quc t: Tetracyclin Cng thc ha hc:

C22H24N208

Tn ha hc: 2-(amino-hydroxy-methylidene)-4-dimethylamino - 6, 10, ll,12a-

tetrahydroxy- 6-methyl-4,4a,5,5 a-tetrahydrotetracene-1,3,12-trione

Tetracyclin c dng bt mu vng, t tan trong nc, dbhng bi nh sng, bi xut qua

thn di dng cn hot tnh, t gy xo trn tiu ha hom chlotetracyclin voxytetracyclin (trch dn bi Hunh ThPhng Quyn, 2008).

Tetracyclin l nhm khng sinh c, c ngun gc tStreptomyces aureoaciens. L thuc

c chvi khun nng thp v dit khun nng cao. N phthuc vo mn

cm ca vi khun i vi thuc. Tetracyclin l khng sinh c phtc dng rt rng, tc

dng nhiu vi khun Gram m v Gram dcmg, ca kh v kkh, xon khun v vi

khun ni bo Camydia, Rickettsia, Mycoplasma, Spirochaete. Nm, nm men, viruskhng nhy cm vi tetracyclin.

Tetracyclin l cht km khun, ging nh nhiu thuc chng nhim trng khc, lm dng

slm cho mt svi sinh vt khng thuc.C chtc dng: Tetracyclin c tc dng km khun l do c chstng hp protein ca

tbo vi khun bng cch gn vo phn 30S ca ribosom nn c chgn aminoacyl-ARNt

mi vo vtr tip nhn (Dc th, 2002).2.4.3.5 Nhm Quinolon

L nhm khng sinh c tc dng dit khun, chng c tc dng c chtng hp ADN do

c chenzyme DNA gyrase lm mt hot tnh ca enzyme ny. Cc thuc thuc nhm


25/5225

ny c pht trin qua 2 thhvi phkhng sinh v c chkhng khun khc nhau.

Thhthnht c phkhng khun hp chyu trn vi khun Gram m, phn bcc

m km. Thhthhai c phkhng khun va nhanh va mnh, phkhng sinh c

mrng trn vi khun Gram m v Gram dng, phn b rt tt cc m (trch dn biHunh Ch Thanh, 2007).

Trong nui trng thy sn cc khng sinh thuc nhm quinolon c sdng kh ph

bin trong iu trbnh mgan do vi khunE. ictalurinh: enroloxacin, norloxacin rtc hiu qu(TThanh Dung v csv,2005).

Cc loi khng sinh thuc nhm ny l: enroloxacin, norloxacin, ciproloxacin,oloxacin...

Enrofloxacin (ENR)

Hnh 2.12: Cng thc cu to enroloxacin

Cng thc ha hc: Ci9H22FN303

Tn ha hc: 1 -Cyclopropyl-7-(4-ethyl-1 -piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-3-

quinolonecarboxylic acid

Enroloxacin thuc nhm luoroquinolon l khng sinh c dng phbin trong nngnghip, thy sn v cy hc, c tc dng rng v tng hp trn c2 nhm vi khun Gramdng v Gram m (trch dn bi Trn Minh Ph v csv,2008).

o o


26/52

Ciprofloxacin (CIP)

26

Hnh 2.13: Cng thc cu to Hnh 2.14: M hnh phn tciproloxacin ciproloxacin

Cng thc ha hc: CI7H18FN303

Tn ha hc: 1-cyclopropyl- 6-fluoro- 4-OXO- 7-piperazin- 1-yl- quinoline- 3-

carboxylic acid

CiproAoxacin l thuc khng sinh bn tng hp, c phkhng khun rng, thuc nhmluoroquinolon, cn c gi l cc cht c ch DNA gase. Do c ch enzym DNA

gase, nn thuc ngn ssao chp ca chromosom khin cho vi khun khng sinh snc nhanh chng.

Ciproloxacin c tc dng tt vi cc vi khun khng li khng sinh thuc cc nhm khc:

aminoglycosid, cephalosporin, tetracycline, peniciline... v c coi l mt trong nhng

thuc c tc dng mnh nht trong nhm luoroquinolon. y l mt Auoroquinolone thhthhai khng khun

Cc vi khun gy bnh ng rut nh: Salmonella, Shigea, Yersinav Vibrio cholerae

thng nhy cm cao.Ni chung, cc vi khun Gram dng (cc chng Enterococcus, Staphylococcus,

Streptococcus, Listeria monocytogenes...)km nhy cm hn. Ciproloxacin khng c tcdng trn phn ln cc vi khun kkh.

Do c chtc dng c bit ca thuc nn ciproAoxacin khng c tc dng cho vi cc

thuc khng sinh khc nh: aminoglycosid, cephalosporin, tetracycline, peniciline...

(Dc th, 2002).


27/52

Norfloxacin (NOR)

27

Q o

'OH

HI"

0

HO

Hnh 2.15: Cng thc ha hc norHoxacin

Tn chung quc t: Norloxacin

Cng thc ha hc: Ci6H18FN303

Tn ha hc: 1 -ethyl-6-fhioro-4-oxo-7-piperazin-1 -yl-1 //-quinoline-3-carboxylic acid

C chtc dng

NorAoxacin c ch DNA-gyrase, mt enzym cn thit cho s sao chp DNA ca vikhun.

Norloxacin c tc dng dit khun vi cvi khun a kh Gram m v Gram dng.

Norloxacin cn c tc dng dit cc chng to penicilinase hoc khng to penicilinase.

Chlamydia v cc vi khun ym kh nh Bacteroides spp khng nhy cm vi

norfloxacin.Norloxacin cng thng c tc dng ngay khi vi khun khng vi acid nalidixic. Skhng i vi norloxacin truyn qua plasmid cha c xc nh (Dc th, 2002).

Oloxacin (OF)Hnh 2.16: Cng thc cu to oloxacin


28/5228

Cng thc ha hc: CigH2oFN304

Tn ha hc: (/?5)-7-fluoro-2-meiyl-6-(4-methylpiperazin-l-yl)-10-oxo-4-oxa-l-

azatricyclo [7.3.1.0513]trdeca-5( 13),6,8,11 -tetraene-11 -caiboxylic acid

Oloxacin l khng snh nhm Huoroqunolon. Oloxacin cphkhng khun rng bao

gm:Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Nesseria

spp, Staphylococcus, Streptococcus pneumoniaev mt vi vi khun Gram dng khc.

Ooxacn c tc dng mnh hn cproloxacn i vi Chamydia trachomatis,

Ureaplasma ureayticum, Mycopasma pnemonae. N cng c tc dng i vi

Mycobacterium lepraev cMycobacterum spp.

Oloxacn ctc dng dit khun, c chtc dng cha c bit y . Ging nh ccthuc quinolon khng khun khc, oloxacn c chDNA-gyrase l enzym cn thit trong

qu trnh nhn i, phin m v tu sa DNA ca vi khun (Dc th, 2002).

2.4.3. Nhm Phenicol

L nhm khng sinh ctc dng km khun nhng cng ctc dng dit khun trong mts trng hp bnh truyn nhim vi nhng diu kin nht nh v nng cao hn.

Thuc c tc dng c chvi khun vi nng thp, hot phca n rt rng, tc dng

trn nhiu loi vi khun Gram m v Gram dng, virus c kch thc ln (trch dn bi

Trn Duy Phng, 2009).

Florfencol (FFC)

Cng thc ha hc: Ci2Hi4Cl2FN04S

Tn ha hc: 2,2-dichloro-iV-[(l/?,25)-3-fluoro-1 -hydroxy-1 -

(4-methanesulfonylphenyl) propan-2-yl] acetamide

FFC l mt loi khng snh thhmi nht ca phencol, l dn xut ca chloramphencol- mt loi khng sinh b cm mt snc trn thgii tgia nhng nm 1990

(Michel, 2003). FFC c sdng rng ri cho ng vt trn cn v ng vt thy sn, ctc dng trn cvi khun Gram m v Gram dng, mt svi khun ni bo (Risketsia,

Chlamidia)vi khun kkh Clostridium spp, Bacteroides spp)(trch dn bi L Thcm

T, 2009).


29/5229

FFC tan tt trong nuc dimethylormamide, methanol, t tan trong acid acetic v kh tantrong nuc (trch dn bi L Thcm T, 2009).

Florfenicol c hot tnh chng li spht trin ca vi khun bng cch kt dnh vi tiu

n v50S ca ribosom, ngn chn cu ni peptid gia cc acid amin v vy c chstng

hcrp protein lm cho vi khun khng cn khnng pht trin v tn ti (trch dn bi LThcm T, 2009).

2.4.3.7 Nhm Aminoglycosid (aminosid)

Kanamycin (K)

Hnh 2.18: Cng thc cu to kanamycin

Cng thc ha hc: CI8H36N4OII

Tn ha hc: 2-(aminomethyl)- 6-[4,6-diamino-3- [4-amino-3,5-dihydroxy-6-

(hydroxymethyl) tetrahydropyran-2-yl]oxy- 2-hydroxy- cyclohexoxy]- tetrahydropyran-

3,4,5-triol

Tc ng khng khun: Kanamycin c tc ng khng vi khun Gram dng, Gram m vMycobacterium tuberculosis. Thuc cng c chng minh hiu qu i vi

Staphylococcusa khng thuc,E.coli v Klebsiella sp.

Kanamycin hot ng bng cch nh hng n cc tiu n v30S ribosome v gy ra

mt t bin missense hoc n ngn cn sphin dch ca RNA (Dc th, 2002).2.4.3.8 Rifamycin (RA)

Hai khng sinh ca nhm l: riamycin sv v riampicin. Chng c tc dng tt i vi

Hnh 2.19: Cng thc cu to riamycin


30/5230

mycobacteria. Riamycin sv c 1 hot phgii hn i vi cu khun Gram dng vGram m, trc khun Gram dng.

Rifampicin l khng sinh bn tng hcrp tkhng sinh tnhin rifamycin B c ly t

mi trng nui cy Streptomyces mediterian,c hot tnh khng sinh yu. Riampicin c

tc dng dit khun. Riampicine c tc dng tt vi cc chng vi khunMycobacterium

c bit lMycobarterium.Riampicin cn l khng sinh phrng, c tc dng tt vi ccvi khun Gram dng vGram m (trcu khun ng rut).

C chtc dng ca Rfampicin: thuc gn vo tiu n vbeta ca ARN- polymerase,

lm sai lch thng tin ca enzym ny, do c chskhi u ca qu trnh tng hpARN mi (Dc th, 2002).

2.5 Cc nghin cu vthuc khng sinh trong nui trng thy sn.

Nhiu nghin cu trong v ngoi nc c thc hin nh gi khnng khng

thuc khng sinh ca vi khunE. ictaluri.Tnm 1986, Waltman v Shotts kim tra s

khng thuc trn 118 chng vi khunE. ictaluriphn lp trn c nheo bnh Mvi 37

loi khng sinh. Kt qucho thy phn ln vi khun ny nhy vi cc thuc th nghim

nhng hn 90% li khng vi colistin v sulamids. en nm 1993, Reger v csv., cng

xc nh cc chng E. ictaluri phn lp trn c nheo cn nhy vi enrooxacin,gentamycin v doxycycline (trch dn bi TThanh Dung v csv, 2009).

i vi vi khunE. ictaluriphn lp tc ha bnh gan thn mVit Nam c nh gi

l nhy hon ton vi thuc khng sinh ampicillin v florfenicol (Crumlish, 2002. Trch

dn bi Nguyn Hu Thnh v Trng Thanh Loan, 2007). Tuy nhin, trong nhng nm

gn y do tnh hnh sdng thuc khng sinh qu nhiu trong diu

trbnh hn c tra nn tnh nhy ca cc loi thuc khng sinh ln nhm vi khun ny

gim rt r, nh nghin cu ca Nguyn Thanh Phng v csv(2005) phn lp c

169 dng vi khun tcc ao nui thy sn BSCL v thvi 6 loi khng sinh v kt

qucho thy 2% khng vi chloramphenicol, c 59% dng vi khun khng vi 4 hay 5

loi khng sinh trong c chloramphenicol. C 34% khng nhiu loi khng sinh nh:

chloramphenicol, ampicillin, tetracyclin, trimethoprim +

sulfamchoxazole, nitrourantion).

Sarter et. al(2008) kho st tnh khng thuc ca cc hvi khun Gram m trn c tra

nui cng nghip BSCL. Kt qunghin cu cng chng minh cc nhm vi khun:

Enterobacteriaceae(49,1%),Pseudomonas(35,2%), Vibrionaceae(15,7%) gim tnh

nhy vi 6 loi thuc khng sinh trong nghin cu: oxytetracyline, chloramphenicol,

trimethoprim-sulphamethoxazole, nitrourantoin, nalidixic acid, ampicillin. c bit tc

gi tm thy hin tng a khng ca cc nhm vi khun trn i vi 6 loi khng sinhny.

Tnh khng thuc khng sinh ca vi khun gy bnh trn c tra khng chxy ra phbin


31/5231

cc vng nc ngt m cn xut hin vng nc lnh: tnh Tr Vinh v Bn Tre. Vi

nghin cu ca Trn Duy Phng (2009) kho st tnh khng thuc ca hai nhm vi khun

Edwardsiellasp v Aeromonassp vng ny cho thy nhm vi khunEdwardsllesp

khng vi streptomycyline (83%), chloramphenicol (58%), florfenicol (50%) v

tetracylin (42%). i vi vi khun Aeromonas sp cn nhy cao vi 3 loi thuc

chloramphenicol, florfenicol v doxycyclin nhng chng khng hon ton vi thuccefazoline.

Qua cc nghin cu vtnh khng thuc khng sinh ca cc dng vi khun gy bnh

ng vt thy sn trn thgii ni chung v trn c tra nui BSCL ni ring, cho thy

tnh khng thuc ca vi khun ngy cng phbin, din bin phc tp v c skhc bit

vtnh khng thuc ca cc chng vi khun cng nh cc vng nui khc nhau. Do

lun cn c nhng nghin cu nh gi vtnh nhy ca thuc khng sinh i vi tng vi

khun tng thi im v tng khu vc nui, nhm gip cho ngi nui c hng iu tr

kp thi v hiu qukhi cc c bnh vi khun xy ra trn c nui.


32/52

CHNG III

32

VT LIU V PHNG PHP NGHIN cu

3.1 Vt liu nghin cu

3.1.1 Thi gian v a im nghin cu

Thi gian thc hin: Tthng 03/2010 n thng 06/2010

a im thc hin: Chi Cc Thy Sn thnh phcn Th, 168 Hai B Trng, thnh phCn Th. in thoi: 07103.751.416.

3.1.2 Vt liu nghin cu

C tra bnh thu t2 tnh: cn Th v An Giang nm 2010 phn lp vi khun kim tra

khng sinh .

3.1.3

Thit b, dng cv ha chtNi khtrng bng p sut (Autoclauve), tm, tcy, cn in t4 sl, my voxtec, tsy...

Bdao tiu phu, dng cthy tnh, bn cn, que cy, micropipet 1 mL v 5 mL.

Cn, NaCl, nc ct, test OZF, test oxidase, test 0/129 (Nam Khoa). Mi trng TSA

(Hng Merck), mi trng MHA (Hng Merck).

Thuc khng sinh: 13 a khng sinh thng mi: ampicillin (AM/10 Jig); amoxicillin

(AMX/25 |ig); cealexin (CN/30 ig); colistin (CS/50 ig); doxycyclin (DO/30 ig);

enroloxacin (ENR/5 ig); kanamycin (K/30 |ig); ciproloxacin (CIP/5 ig); riamycin

(RA/40 ig); tetracyclin (TE/30 ig); norloxacin (NOR/5 ig); oloxacin (OF/10 ig) (hng

Bio-rad, ngoi trflorfenicol (FFC/30 ig) ca hng Oxoid).

3.2 Phng php nghin cu

3.2.1 i tng nghin cu

Mu c tra bnh xut huyt v mgan c thu 2 tnh: cn Th, An Giang nm 2010 (10chng mi dng vi khun).

Dng phng php lm khng sinh trn vi khunEdyvardsiellasp vAeromonas spvi 13 loi khng sinh.

3.2.2 Phng php thu mu

Mi ao c tra: thu 5 con c tra c du hiu bnh l c trng: c l, bi dt vo b, mtli, ph u, xut huyt... v 2 c khe.

Tui c: tgiai on c ging trln.


33/5233

Khi thu mu c c thu km theo cc thng tin vtui c, kch cc, du hiu bnh l ca

c... u c ghi vo phiu thu mu c (xem phlc A. 1).

Sau khi thu mu xong, c c vn chuyn bng ti nylon bm oxy. Mu c c chuyn

vo phng th nghim Chi Cc Thy Sn thnh phcn Th, tin hnh mc ngay trongngy ly vi khun phn tch.

3.2.3 Phng php phn lp v nh danh vi khun

Git c bng cch hy ty, sau mc.

Cy mu vi sinh tgan, thn, ttng ca c tra trn mi trng TSA, trong iu kin v

trng, cc a c cy vi khun trong tm 30c.

c kt qusau 24 gii viAeromonassp, 48 gii viEdwardsellasp.

Ghi nhn cc c im ca khun lc nh hnh dng mu sc.

Chn khun lc ri, c hnh dng c trng v chim u thtch rng, nh danh v lu

gilm khng sinh .Khi vi khun thun th tin hnh thc hin cc bc sau:

Nhum Gram (xem phlc A.2)

Tnh di ng (xem phlc A.3)

Phn ng oxidase (xem phlc A.4)

Phn ng catalase (xem phlc A.5)

Khnng ln men v oxy ha ng glucose (0/F test) (xem phlc A.6)

Phn ng 0/129 (xem phlc A.7)G-ram stain

(+) (-)

I(-) oxidase (+)

Glucose utilizationEvarsiela

I IOxidative fermentative

Pseudomonas

(+) sensitivity to 0/129 (-)

VibrioAeromonas

Hnh 3.1: Quy trnh phn lp vi khunEdwardsiellasp vAeromonassp3.2.4 Phng php lm khng sinh

Phng php lm khng sinh trn 2 nhm vi khunAeromonassp vEdyvardsiella sp,


34/5234

s dng mi trng MHA, chn 13 loi thuc khng sinh: ampicillin (AM/10 lg);amoxicillin (AMX/25 Jig); cealexin (CN/30 ig); colistin (CS/50 Jig); doxycyclin(DO/30 fig); enroloxacin (ENR/5 fig); kanamycin (K/30 ig); ciproloxacin (CIP/5 fig);riamycin (RA/40 fig); tetracylin (TE/30 fig); norloxacin (NOR/5 fig); oloxacin (OF/10fig); florfenicol (FFC/30 Jig).

o ng knh v trng (min): nhm xc nh loi khng sinh nhy, trung bnh v khng.Mi trng thch

Ha tan mi trng TSA, MHA theo hng dn trn nhn chai, thanh trng 121c trong

15 pht.

ngui mi trng khong 50c, mi trng ra a petri thy tnh dy khong 4mm.

Sau 45 pht khi a mi trng kh th lt a li cho vo ti nilon (tit trng ti nilon bng

cn 70) v ng kn ming ti.

t a vo tm 30c trong 24 gikim tra snhim khun.Nc mui sinh l

Ha tan 0,85g NaCl trong 100 mL nc ct, cho 5 mL nc mui sinh l vo tng ng

nghim, thanh trng 121c trong 15 pht.

Mt svi khun c xc nh da vo phng php so mu trn my quang ph

Vi khun sau khi tch rng v thun th tin hnh kim tra khng sinh .

Dng que cy tit trng nht t nht 3 khun lc cho vo ng nghim cha 5 mL nc

mui sinh l (0,85% NaCl) tit trng, trn u trn my voxtec v xc nh mt sda

vo my so mu quang ph, bc sng 625 nm vi gi trOD= 0,08-0,13+0,02 th mtvi khun l 108CFU/mL.

Sau khi xc nh mt vi khun th tin hnh cho vi khun ln mi trng

Dng tm bng tit trng nhng vo dung dch vi khun, qut u ln mi trng thch

MHA. Sau yn 1 pht ri dng pel tit trng ly a thuc khng sinh t vo a

petri sao cho khong cch gia 2 tm ca a thuc khng sinh khong 24 mm v khong

cch gia tm a khng sinh vi mp ra ca a petri l 10-15 mm. Mi a petri (d> 100

mm) mi trng t ti a 6 a khng sinh.

Sau khi hon tt vic dn a khng sinh, t a petri vo trong tm iu kin nhit

30c. Sau 24 gi tin hnh c kt qu i vi Aeromonas sp, 48 gi i viEdyvardsiellasp.

c kt qu: sau 24 gi(vi khun gy bnh xut huytAeromonassp), 48 gi(vi khun

gy bnh gan thn mEdyvardsiellasp). Xut hin vng v trng (vng trn khng c vi

khun pht trin) mi a khng sinh. ng knh v trng xc nh tnh nhy cm ca


35/5235

vi khun vi thuc khng sinh. o ng knh vng v trng (mm) da vo chun ng

knh vng v trng theo tiu chun ca Clinical and Laboratory (CLSI) (2006) xc nh

loi khng sinh nhy, trung bnh nhy v khng.


36/52

CHNG IV

36

KT QUV THO LUN4.1 Kt quphn lp v nh danh vi khunEdwardsellasp vAeromonassp

C tra l loi sinh vt sng trong mi trng nc, mt mi trng tn ti rt nhiu loi vi

khun. Mt sloi vi khun c hi c thxm nhp vo c thc m khng gy nn tchi. Ngoi ra, c mt strng hcrp c cht do cc yu tgy sc, m nguyn nhn khng

phi do vi khun. Do , xc nh nguyn nhn gy cht c, cn phi tin hnh phn lp

v nh danh vi khun. Mu c tra c thu tnhng ao c c du hiu bnh, cy gan,

thn v ttng ca cc mu c c du hiu bnh mgan, xut huyt, ln mi trng TS A,

nhng khun lc chim u th, c mu sc, hnh dng v kch thc c trng ca nhm

Aeromonassp (24 gi) vEdwardsiellasp (48 gi) c tch rng, sau kim a mt s

chtiu cbn gm: nhum Gram, tnh di ng, oxydase, catalase, phn ng 0/F, 0/129.

Ket qukim ta cc chtiu ny c thhin Bng 4.1

Hnh 4.1: Ni tng c a bbnh m

gan

Hnh 4.2: C a bbnh xut huyt, Hnh 4.3: Ni tng c a bxut huyt mt bsng v li, cc vi v da c nhiu m


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* c y vi khu n

Hnh 4.4: Kt qutch rng Hnh 4.5: Kt qutch rngvi khunEdwardsiellasp vi khunAeromonassp

Theo m tca TThanh Dung (2004) khun lc Edyvardsiellasp pht trin trn mi

trng TSA sau 48 giiu kin nhit 30c, kch thc li t c mu trng c. Khun

lc Aeromonassp pht trin trn mi trng TSA sau 24 giiu kin nhit 30c,

kch thc nh, ng knh 1-2 mm, mu trng c hay mu kem.

Bng 4.1: Ket qukim a cc c im sinh ha ca vi khunEdvvardsieasp vAeromonassp

Hnh 4.6: Hnh nhum Gram ca vi Hnh 4.7: Hnh nhum Gram ca vikhunEdwardsiellasp (100X) khunAeromonassp (100X)

STT Chtiu Edwardsiellasp Aeromonassp

1 Nhum Gram-

-

2 Di ng + +3 Oxydase - +4 Catalase + +5 0/F +/+ +/+6 0/129 Khng

Ghi ch: (+): Dng; (-): m * Nhum Gram


38/5238

* Test 0/FHnh 4.8: Vi khunAeromonassp Hnh 4.9rVrkhunAeromonassp cho

mi thc hin test 0/F phn ng ln men sau 24h

Qua kt qukim tra ban u vhnh dng v cc chtiu sinh ha ca cc chng vi khun

Aeromonassp ging nh m tca Bi Quang T(2006), y l vi khun Gram m, hnh

que ngn, hai u hn, di ng nhtim mao, oxydase dng tnh, catalase dng tnh,

cho phn ng ln men, khng mn cm vi thuc th0/129.

i vi chng Edyvardsiella sp ging nh m t ca Bi Quang T (2006), y l vi

khun Gram m, hnh que mnh, oxydase m tnh, catalase dng tnh, ln men trong mitrng OZF glucose.

4.2 Kt qukhng sinh

Hin nay, c rt nhiu sla chn cc loi thuc khng sinh v ha cht iu trbnhtrn c tra. Tuy nhin, do hiu bit hn chca ngi dn vc tnh ca khng sinh, cch

sdng, liu dng v thi gian sdng... c bit l tnh c hi ca n i vi sc khe

con ngi ngy cng bo ng. Vic sdng ba bi v lm dng khng sinh trong vic

phng v trbnh lm cho khnng khng ca cc vi khun ngy cng mt tng v

c nhng chng vi khun hu nh khng vi hu ht cc loi khng sinh. V th, vic s

dng thuc khng sinh thch hp sgim nhng ri ro m bnh c thxy ra. Do ,

xc nh loi khng sinh hiu quv trnh khnng to ra nhng dng vi khun khng

thuc th phi tin hnh kim tra khng sinh trc khi sdng.


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4.2.1 Kt qukhng snh ca vkhunEdwardsieasp ti cn Th v An Giang

Kim a khng sinh i vi vi khunEdvvardsiellasp, sau 48 gimi a khng snh

xut hin vng v, ng knh vng v trng xc nh tnh nhy ca vi khun.

ng knh vng v trng da vo chun ng knh vng v trng theo tiu chun ca

Clinical and Laboratory (CLSI) (2006): Nhy (>20 mm), nhy trung bnh (15-19 mm),khng (


40/52

Bng 4.2: Tlphn trm tnh nhy ca 10 chng vi khunEdxvardsiellasp vi 13 loi khngsinh

40

Theo kt quBng 4.2 cc chng vi khunEdwardsiellasp cn nhy rt cao vi nhm

beta-lactamin cthl: ampicillin (80%), amoxicillin (80%) v theo Trn Duy Phomg

(2009) cc chng vi khun nhy 100% vi ampicillin. Theo Depaola et. al (1995) nghin

cu skhng thuc ca 22 chng vi khunEdwardsiellasp trn 2 loi khng sinh ny

cng khng tm thy chng no bkhng. V tnh nhy ca nhm khng sinh ny cao, nn

ngi dn sdng rng ri v thng xuyn nn tnh nhy ca n c gim. Tuy nhin,

nhm khng sinh ny vn cn hiu qucao i vi vi khun Edyvardsiella sp. Trong

nhng trng hp c tra bnh nng do nhim vi khunEdwardsiellasp c thsdngnhm khng sinh ny iu tr.

Cc chng vi khunEdwardsiellasp cng nhy vi khng sinh cealexin (50%), cng c

th sdng khng sinh ny trong trng hp c tra bc pht bnh nhng hiu qu skhng cao bng nhm khng sinh beta-lactamin.

Nghin cu cho thy hu ht vi khunEdvvardsiellasp cn hiu quvi nhm khng sinh

quinolon, trong c ciprooxacin nhy cao nht (90%), nhng vi khunEdvvardsiella

sp li khng vi enroloxacin (50%). Nghin cu trc y ca Stock v Wiedemann

(2001) xc nh vi khunEdwardsiellanhy vi cc khng sinh thuc

STT Khng sinh SchngkhngNhay

(%) Nhay TB

(%)Khng

(%)

1 Beta-lactaminAmpicillin 0 80 20 02 Amoxicillin 1 80 10 10

3CcfalosporinCefalexin 1 50 40 10

4PolymyxinColistin 10 0 0 100

5TetracyclinDoxycyclin 6 40 0 60

6 Tetracyclin 7 30 0 70

7QuinolonEnroloxacin 5 10 40 50

8 CiproHoxacin 1 90 0 109 Norloxacin 3 10 60 3010 Otoxacin 2 20 60 20

11PhencolFlorfenicol 6 40 0 60

12AminoglycosidKanamycin 6 10 30 60

13

KhcRifamycin 7 0 30 70


41/5241

nhm quinolon (trch dn bi T Thanh Dung v csv, 2009). Nhng kt qu ca

Akinbowale et. al (2007); Dung et. al (2008) vi khun Edvvardsiella khng vi nhm

khng sinh ny (trch dn bi TThanh Dung v csv,2009). Hin nay nhm quinolon

ang c khuyn co hn chsdng, nhng theo iu tra ca Tin Ho (2009) li

c n 62,5% shnui sdng khng sinh nhm ny. Quinolon l nhm thuc khng

sinh c sdng rng ri chuyn dng trcc bnh nhim trng v l nhm khng sinhcc kquan hng trong y hc, khng nn lm dng nhm khng sinh ny v c thsto

ra cc chng vi khun khng thuc vnh vin. Do , vic dng thuc nhm khng sinhny trong thy sn cn ht sc thn trng.

Theo nghin cu ca Nguyn Hu Thnh v Trng Thanh Loan (2007) c n 72,3%

chng vi khun Edvvardsiella ictaluri nhy vi nhm tetracyclin v theo Chu Hng

Thy (2008) tnh nhy ca cc chng vi khun l 60% vi tetracyclin, 66,7% vi

doxycyclin. Gn y nghin cu ca Trn Duy Phng (2009) cn li 58% chng vi

khun nhy vi nhm tetracyclin. Nhng theo kt qunghin cu TThanh Dung v csv

(2009) li cho thy 64% chng vi khun khng vi tetracyclin v 56% khng vi

doxycyclin v theo kt qunghin cu ny cng cho thy cc chng vi khun khng vi

nhm tetracyclin, doxycyclin (60%), tetracyclin (70%). Trong qu trnh nui do nhm

thuc ny c sdng lu di nn tnh nhy ca thuc gim dn theo thi gian, v theo

kt quiu tra ca Trn Duy Phng (2009) vn cn kh nhiu hnui (41,94%) s

dng nhm thuc ny. Nn trong qu trnh nui cn cn nhc li tnh trng sdng nhmthuc ny.

Ngoi ra, kt qukim tra khng sinh vi 13 loi thuc khng sinh trn th cc chng vi

khunEdwardsieasp khng vi kanamycin, colistin, riamycin , tlkhng cao ln lt

l; 60%, 100% v 56,9%. Kanamycin t c ngi dn sdng rng ri, v tnh nhy ca

n khng cao, mt phn cng do c tnh ca khng sinh ny c hiu qukhng cao i

vi vi khun. Colistin khng tnhin vi vi khunEdwardsiella ictaluri,trong cng thc

pha chmi trng c trng caEdvvardsiea ictaluri, ngi ta dng colistin c trong

thnh phn ca mi trng chn lcEdwardsiella ictaluriagar (EIA). Do , khng nn

sdng cc khng sinh ny trong vic diu trbnh do vi khunEdwardsiellasp gy ra, vsgy tn km cho ngi nui m khng em li hiu qu.

Kt qu nghin cu cho thy chng vi khun Edwardsiea sp khng vi florfenicol

(60%). Florfenicol c sdng phbin trong ngnh nui trng thy sn. Trong nhng

nm gn y ktkhi cm sdng chloramphenicol, theo kt quiu ha ca Trn Duy

Phng (2009) khng sinh florfenicol c ng dng rng ri trong iu trbnh mgan

c tra (61,3%). Bo co ca T Thanh Dung v csv (2008) khng c chng

Edwardsiellaphn lp tc tra bnh mgan khng vi florfenicol, cho thy khng sinh

ny c tnh nhy rt cao. Tuy nhin, kt qunghin cu ca TThanh


42/5242

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s'pa

35

30

25

20

15

10

5

30

22

32.4

24.4 I

1 1

18.6

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19.4

1 1 T r 10.812ri

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25.6

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An Giang

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AM AMX CN cs DO TE ENR CIP NOR OF FFC Khng sinh RA

Dung v csv(2009) c n 73,5% chng vi khunEdyvardsiellakhng vi florfenicol.

Theo trch dn ca T Thanh Dung v csv (2009) tnh khng ca vi khun vi thuc

lorenicol tng nhanh do thng qua c cho thi protein, m ha gen lin quan n

integron (Arcangioli et. a,1999; Cloeckaert et. al,2000) v qua plasmid (Keys et. al,

2000). V thnn cn trng khi dng loi khng sinh ny, trnh tnh trng lm dng.

Hnh 4.11: ng knh trung bnh v trng ca thuc khng sinh i vi

Edwardsiellasp ti cn Th v An Giang

THnh 4.11 cho thy: trong 13 loi khng sinh c dng lm khng sinh th chc 4

loi: ampicillin, amoxicillin, cealexin, ciproloxacin u nhy vi vi khunEdwardsiella

sp c2 tnh cn Th v An Giang. ng knh vng v trng dao ng l t18,6-32,4

mm. Ciproloxacin thuc nhm quinolon, l nhm thuc c hot tnh khng khun vanhanh va mnh v c tc dng dit khun trn cvi khun Gram m v Gram dng

(Aeromonas, Edyvardsiella, Pseudomonas).Theo kt qunghin cu ca HThKiu

Nga (2009), cho thy ciproloxacin u nhy vi cc vi khun kim tra, cho ng knh

vng v trng dao ng (19-47 mm), amoxicillin (16- 50 mm). Tkt quHnh 4.11 cng

cho thy: ciproloxacin, amoxicillin nhy viEdvvardsiellasp c2 tnh cn Th v An

Giang. C thsdng loi khng sinh ny iu tr trong cc trng hcrp a nhim

khun. Tuy nhin, ciproloxacin nm trong danh mc cm sdng i vi thtrng EU

v nm trong danh mc hn chsdng nc ta. V th, khi sdng khng sinh ny ta

cn lu khi sdng hoc khuyn co ngi dn trong iu trbnh. cn Th v AnGiang 4 loi khng sinh ampicillin, amoxicillin, cealexin, ciproAoxacin c ng dng

rng ri trong thy sn v hiu quca n kh cao, trong trng hp c tra bc pht bnh

c thsdng cc loi khng sinh ny iu tr. Nhng trong qu trnh nui, nu s

dng cc loi khng sinh ny thng xuyn trong vic phng bnh cho c, th vlu di s

to ra


43/5243

nhng dng vkhun khng thuc, rt cthkhng lu cc loi khng sinh skhng vi vikhun, chnn sdng trong vic iu trbnh.

Vi m loi khng sinh th ng knh v trng trung bnh ca khng sinh vi

Edwardsiella sp An ang ln hn cn Th. Ba loi khng sinh: enrofloxacin,

norfloxacin, oAoxacn thuc nhm qunolon v doxycyclin, teacycn thuc nhmtetracyclin c sdng cn Th c hin tng khng vi vi khunEdwardsiellasp

(20 mm), nhy trung bnh (15-19 mm),

khng (


44/52

Bng 4.3: Tltnh nhy ca 10 chng vrkhunAeromonassp vi 13 loi khng sinh

44

Qua kt quBng 4.3 cho thy c 7 loi khng sinh cn nhy vi vi khun v phn trm

nhy ca cc chng vi khunAeromonassp i vi cc loi khng sinh l kh cao. c

bit, cc chng vi khun ny rt nhy vi nhm quinolon.

Theo Sarter et. al(2007) th cc dng vi khun Gram m phn lp tmi trng nui c

tra khng vi tetracyclin. Mohamed Nawaz (2006) vi khunAeromonaskhng 25%

vi tetracyclin. Hunh ThThy Hng (2008) li cho thy vi khunAeromonas khng vi

doxycyclin. Tuy nhin, kt quBng 4.3 li cho thy cc chng vi khun nhy vi nhm

tetracyclin, tetracyclin (50%), doxycyclin (40%). T lphm trm nhy ca tetracyclin

(50%) v khng l (50%), do khng sinh ny rt dxy ra hin tng khng thuc

trong trng hp sdng lu di. Ket qukim ta khng sinh ca vi khunAeromonassp cho thy nhy vi doxycyclin (Cao Anh Tun, 2005). ng thi theo TThanh Dung

(2005) cho rng nn sdng doxycyclin iu trbnh do vi khunAeromonassp gy

ra. Do vi khunAeromonassp gy bnh trn nhiu i tng c nc ngt, nn vic s

dng thuc khng sinh trong mi trng nui ngy cng nhiu v tng theo thi gian, nn

khnng khng thuc cng tng theo. Tcc nguyn nhn trn dn n sai khc kt qu

khng sinh cng l hp l.

STT Khng sinh SchngkhngNhay

(%)Nhay TB

(%)Khng

(%)

1

Beta-lactamin

Ampicillin 10 0 0 1002 Amoxicillin 10 0 0 100

3CefalosporinCefalexin 10 0 0 100

4PolymyxinColistin 7 0 30 70

5TetracyclinDoxycyclin 2 40 40 20

6 Tetracyclin 5 50 0 50

7QuinolonEnroloxacin 0 90 10 0

8 CiproHoxacin 0 100 0 0

9 Norloxacin 0 90 10 010 OHoxacin 1 90 0 10

11PhenicolFlorfenicol 4 60 0 40

12AminoglycosidKanamycin 6 10 30 60

13KhcRifamycin 9 0 10 90


45/5245

Cn Ths An Giang

Nhiu nghin cu trc y th vi khunAeromonassp khng tnhin vi ampicillin,

amoxicillin, cealexin. Kt qunghin cu trn cho thy 100% vi khunAeromonas sp

c phn lp cn Th v An Giang khng vi 3 loi khng sinh ny. Ngoi ra, kt qu

lp khng sinh ca 10 chng vi khunAeromonassp c phn lp tmu nc vng

nc ngt Bangladesh cng ghi nhn rng vi khun Aeromonas sp khng vi

amoxicillin (Bazlur and Valerie, 1994). Ket qunghin cu ca Cao Anh Tun (2005)

cng cho thy vi khun Aeromonas sp khng vi amoxicillin. Hunh Th Thy Hng

(2008) cho thy vi khunAeromonassp u khng vi amoxicillin v cealexin. Bit c

tnh khng tnhin ca 3 loi khng sinh ny, sgip cho ngi nui gim c chi ph

trong vic la chn v sdng thuc khng sinh.

Khng sinh

Hnh 4.13: ng knh trung bnh v trng ca thuc khng sinh i viAeromonassp ti cn Th v An Giang

Theo Hnh 4.13 cho thy: hiu quca cc loi khng sinh i vi vi khunAeromonassp

cn Th v An Giang khng chnh lch c ngha, kt qulm khng sinh vi 13

loi khng sinh cn Th v An Giang th ch8 loi khng sinh cho hiu quvi vi khun

Aeromonas sp l ciproloxacin (23,6 v 27,7 mm) c tnh nhy cao nht, k tip l

enroloxacin, oloxacin, norloxacin, doxycyclin, tetracylin ng knh trung bnh v

trng dao ng t 15,4-27,6 mm. Ket qu ny ph hcrp vi c tnh sinh ha ca

Aeromonassp, v cc khng sinh ampicillin, amoxicillin, cealexin khng mc nh viAeromonassp.

Tuy nhin, i vi khng sinh florfenicol c strn lch cao, cn Th th florfenicol

nhy vi vi khunAeromonassp (25,6 mm), khi sdng florfenicol scho hiu qucao,

cn An Giang th florfenicol c hiu quvi vi khunAeromonassp nhng vi mc

trung bnh (17,6 mm). i vi khng sinh kanamycin th cn cho hiu


46/5246

100

Edwardsiela sp EO

eromonas sp

Khng sinh

qumc trung bnh vi vi khunAeromonassp cn Th v ng knh vng v trng:

15,4 mm, cn An Giang vi khunAeromonassp khng vi kanamycin v ng knh

vng v trng 12 mm. Florfenicol v kanamycin c skhc bit hai tnh ny l do hai

a phng khc nhau nn tnh hnh sdng khng sinh gia 2 vng cng khc nhau. An

Giang c lch snui c tra sm hn cn Th nn sdng khng sinh thi gian di dn

n hiu qusdng khng sinh gim xung. c bit, kt qukanamycin cng cho thy

khi s dng kanamycin khng cn hiu qu i vi Aeromonas sp An Giang, v

kanamycin l loi khng sinh thhcv c sdng nhiu thi gian trc y.

4.2.3 Kho st tnh nhy ca vi khunEdwardsellasp vAeromonassp cn Th

v An

Giang

75% l: enroloxacin,

ciproloxacin, norloxacin, oloxacin. Khi dng nhm quinolon chng ta phi cn thn khisdng, v nhm khng sinh ny ang nm trong danh mc hn chsdng.

Ring ciproAoxacin l khng sinh nhy cEdwardsiellasp vAeromonassp, cho nn c

thdng khng sinh ny trc nhim 2 bnh cng xut hin. Tuy nhin, cng


47/5247

Aeromonas spEchvardsellasp

Hnh 4.15: ng knh trung bnh v trng ca thuc khng sinh i viAeromonassp vEdwardsellasp ti An Giang

hn chsdng khng sinh ny v phi xc nh c thi gian xut c c ththi

gian o thi ciproloxacin.

Qua Hnh 4.15 c ththy rng: trong 13 loi thuc khng sinh c dng lm khng

sinh An Giang, th c 7 loi khng sinh cho kt qunhy vi c2 loi vi khun

Aeromonassp vEdwardsiellasp, l: doxycyclin, tetracyclin, enroloxacin, oloxacin,

norloxacin, ciproloxacin, florfenicol. iu cng cho thy khi sdng cc loi khng

sinh ny scho hiu quvi c2 loi bnh: bnh xut huyt v bnh mgan, nh vytrong trng hcrp c ha xut hin 1 trong 2 loi bnh khi sdng cc loi khng sinh trn

th vic iu trscho hiu qungay i vi bnh , ng thi cng sngn chn c

bnh cn li khi c va chm bnh, sgim c chi ph cho ngi nui. Qua kho st

vng nui c tra An Giang cho thy 100% ngi nui xc nhn c sdng khng sinh

trong phng trbnh cho c, trong cc loi khng sinh thuc nhm quinolon c s

dng nhiu nht (Nguyn Chnh, 2005).

Cn i vi cn Th th ch c ciproloxacin cho kt qu nhy vi c 2 vi khun

Aeromonassp (23,6 mm) v Edwardsiellasp (21,2 mm). Do vic sdng thuc khng

sinh phng v trbnh cho c nui. Kt quiu ha ca Nguyn Quc Thnh (2006)vic sdng thuc khng sinh trong nui trng thy sn gia tng hng nm trong vic iu

trbnh, trong khi shiu bit ca ngi nui vthuc khng sinh cn hn ch, a phn

ngi dn sdng theo kinh nghim, vic lm dng khng sinh ca


48/5248

ngi nui cn rt phbin, khi c c du hiu bnh tng tbnh trc y th ss

dng li loi khng sinh iu trtrc , nu khng c hiu quschuyn sang khng

sinh khc. Theo kt qunghin cu Hunh Ch Thanh (2007) nhn thy rng tnh hnh

dch bnh trn c tra cha thy pht hin bnh mi, nhng cng nhim bnh ngy

cng tng, lng thuc khng sinh sdng ngy cng cao hn, nhng tlsng li thp

hn. iu cho thy phn no hu quca vic sdng khng sinh ba bi, sdng

khng ng liu, dn n hnh thnh cc dng vi khun khng thuc. Tnh trng sdng

thuc khng sinh ba bi v thiu kim sot nh vy c thdn ti nhiu loi khng sinh

thng dng c php sdng trong nui trng thy sn sbkhng vi nhiu loi vi

khun. Theo nghin cu ny th chc ciproloxacin cho kt qunhy vi c2 vi khun,

nhng ciproloxacin ang l khng sinh nm trong danh mc hn chsdng Vit Nam,

nn vic sdng khng sinh ny cng nn thn trng. Do , nu khng c bin php khc

phc nhiu khnng vic khng thuc scn gia tng theo thi gian.


49/5249

CHNG y

KT LUN V XUT5.1 Kt lun

Kt qu phn lp c 10 chng vi khunEdwardsiellasp vAeromonassp 2 tnh

Cn Th v An Giang.Ket qukhng sinh cho thy cc loi khng sinh nhy vi cc chngEdwardsella sp:cealexin (50%), ampicillin (80%), amoxicillin (80%), ciproloxacin (90%).

Cc loi khng sinh nhy vi cc chng Aeromonas sp: florfenicol (60%), oloxacin(90%), norloxacin (90%), enroloxacin (90%), ciproAoxacin (100%).

Kt qu khng sinh cn Th cho thy: ampicillin, amoxicillin, cealexin,

ciproloxacin nhy vi Edvvardsiela sp. Enroloxacin, ciproloxacin, norfloxacin,oloxacin v florfenicol nhy viAeromonassp.

Ket qukhng sinh An Giang cho thy: ampicillin, amoxicillin, ciproloxacin vflorfenicol nhy vi Edwardsiella sp. Enroloxacin, ciproAoxacin, noroxacin v

oAoxacin nhy viAeromonassp.

Cc loi khng hiu quvi cvi khunEdvvardsiellasp vAeromonassp, An Giang

l: doxycyclin, tetracyclin, enroloxacin, oloxacin, noroxacin,

ciproloxacin v florfenicol. cn Th th chc ciproloxacin cho kt qunhy vi c2vi khun.

5.2 xut

Mrng ti quy m ln hn nh: slng mu v nhiu a phng hn.

Nghin cu su hn vc chtc dng ca thuc khng sinh i vi vi khun gy bnh

trn c ha nui ca vng nc ngt v nc lBSCL.

Nghin cu hon thin quy trnh phng trbnh trn c ha. Tp hun v hng dn kthut phng trbnh trn c ha cho ngi nui.

Khuyn co n ngi nui cc khng sinh cho hiu qucao trong vic iu trbnh.

ti iu a v phn tch thc tng cht lng khng sinh nguyn liu n thtrng

dng diu trbnh thusn.TI LIU THAM KHO

Ting VitBi Quang T, 2006. Bnh hc Thy Sn. Vin nghin cu nui trng thy sn I. NXB

nng nghip. 439 trang.

Cao Anh Tun, 2005. Thnh phn ging loi vi khun v k sinh trng trn c tra ging

(Pangasius hypophthalmus)huyn Tn Chu, tnh An Giang. Lun vn i hc, khoathy sn, trng i Hc cn Th. 42 trang.


50/5250

Chu Hng Thy, 2008. Kho st tnh hnh xut hin bnh m gan do vi khun

Edwardsiella ictaluri trn c tra nui thm canh tnh Tr Vinh. Lun vn cao hc2008, Khoa Thy Sn, i Hc cn Th, 75 trang

ng Th Hong Oanh, on Nht Phng, Nguyn Minh Hu v Nguyn Thanh

Phng. Thit lp bsu tp vi khun khng thuc khng sinh chloramphenicol ti

khoa Thy Sn, i Hc cn Th. Tp ch nghin cu Khoa Hc 2004: 2 76-81.

ng ThHong Oanh. Xc nh tnh khng thuc khng sinh ca vi khun phn lp t

cc hthng nui thy sn ng Bng Sng Cu Long, Vit Nam. Tp ch nghincu khoa hc 2005: 136-144.

Tin Ho, 2009.Tnh hnh xut hin bnh m gan trn c tra (Pangasianodon

hypophthalmus)nui thm canh mt stnh ng Bng Sng Cu Long. Lun vni hc. Khoa Thy Sn, i Hc cn Th.

HThKiu Nga, 2009. Nghin cu kiu Plasmid v tnh khng thuc khng sinh ca vi

khun Edwardsiella ictaluri gy bnh m gan trn c tra (Pangasianodonhypophthalmus).Lun vn i hc.

Hi ng dc in Vit Nam, 2002.Dc in Vit Nam. Ln xut bn thba.

Hunh Ch Thanh, 2007. Xc nh c im sinh ha v bc u th nghim iu tr

bnh Edwardsiella ictaluri gy bnh trn c tra (Pangasianodon hypophthalmus)bng khng sinh. Lun vn i hc.

Hunh ThPhng Quyn, 2008. Tiu chun ha phng php xc nh nng c ch

ti thiu (MIC) ca thuc khng sinh ln vi khun Edyvardsiella ictaluri vAeromonas hydrophilati khoa thy sn. Lun vn i hc.

Hunh ThThy Hng, 2008. Tiu chun ha phng php lp khng sinh trn vi

khunEdyvardsiella ictalurivAeromonas hydrophilati khoa thy sn. Lun vn

i hc.

L ThCm T, 2009. Kho st nh hng ca Florfenicol ln mt schtiu huyt hc

ca c tra (Pangasianodon hypophthalmus)ging nui trn b. Lun vn i hc.

Ng Minh Dung, 2007. Nghin cu kh nng gy bnh ca vi khun EdyvardsiellaictalurivAeromonas hydrophilatrn c tra (Pangasianodon hypophthalmus). Lunvn i hc.

Nguyn Chnh, 2005. nh gi tnh hnh s dng thuc, ha cht trong nui c tra(Pangasius hypophthalmus)thm canh An Giang v cn Th. Lun vn i hc.

Nguyn Hu Thnh v Trng Thanh Loan, 2007. Phn lp v kho st c im khng

sinh ca Edwardsiella ictaluri gy bnh gan thn m trn c tra (Pangasius

hypophthalmus)nui thm canh. Tp ch Khoa Hc KThut Nng Lm Nghip s1&2/2007. Trang 175-179.


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Nguyn Quc Thnh, 2006. iu tra nh gi nh hng vic sdng thuc v ha cht

trong qu trnh nui c tra (Pangasius hypophthalmus)b. ti cp trung. Khoathy sn i hc cn Th.

Nguyn Vn Kim, 2004. C skhoa hc v k thut sn xut c ging, NXB nngnghip, 21-38.

Nguyn Vn Thng. Tng quan dn liu v nh loi c tra (Pangasianodon

hypophthalmus)phn b vng h lu sng Mekong. Tp ch Khoa Hc 2008:1

82-90 .

Phm Vn Khnh, 1996. Sinh sn nhn to v nui c tra (Pangasianodonhypophthalmus)(Sauvage, 1878). Lun n ph tin skhoa nng nghip. Trng iHc Thy Sn Nha Trang.

Phan Th M Hnh, 2004. Nghin cu mt s yu t nh hng bnh vi khun do

Edwardsiella ictaluri trn c tra (Pangasianodon hypophthalmus) BSCL. Lun

vn i hc.Trn Anh Dng, 2005. Kho st cc tc nhn gy bnh trong nui c tra (Pangasianodon

hypophthalmus)thm canh tnh An Giang. LVCH. Khoa Thy Sn. HCT.

Trn Duy Phng, 2009. nh gi skhng thuc khng sinh ca vi khun gy bnh trn

c tra (Pangasianodon hypophthalmus)nui vng nc ltnh Tr Vinh - Ben Tre.Lun vn i hc.

Trn Minh Ph, o ThHng Sen, ThThanh Hng v Trn ThThanh Hin. Xc

nh thi gian tn lu EnroAoxacin trn c tra (Pangasianodon hypophthalmus).Tp

ch Khoa Hc 2008: 2 215-218.TThanh Dung, ng ThHong Oanh, Trn ThTuyt Hoa. Bnh hc Thy Sn,

2005, trang 50-69 .

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vi khun Edwardsiella ictaluri gy bnh gan thn m trn c tra (Pangasius

hypophthalmus)ng Bng Sng Cu Long. Kyu Hi nghkhoa hc thy snTon Quc, trang 219-225.

Ting Anh

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