KHOA HOC C 6 N G N G H £
XAC DIIVIH DAC TifSlH CUA VI KHUAlV Aeramanas hydraphala PHAIVI L A P TU IVIOT SO LOAI CA IVUQC
rUGOT B! BEI\IH X U A T H U Y £ T DOIVI D O O IVIOT SO TIIVH
odrviG BAIVG BAC B O
Pham C6ng Hoat'
T6M TAT
7 chung vi khuan Ahydrophila ducx- pbaii lap tii cn chep, tram (V khu vuc dong bang Bic bg co dac tinh sinh hoa dien hinh cua lo.-ii, do la: co kha nang di dgng, ldn men duong glucoza, lactoza, sinh HoS. sinh hoi, sinh indol, calalaza duoiig tinh, Relalinaza duong tinh, dung huy^t thach mau kieu a va p. Hai trong so 7 chung Ahydrophila CS va C8 duoc sir dung de nghidn cim dac tinh thich nghi cho thay: ca hai chiing ddu la vi khuan ua ."ini, thai gian va nhirl do thicli ho^) nhat cho sir phat trien tuong img la 36 gio va 28''C; a khoang nhiet do tir 18-37"C r.i hni cluing vi khuan deu san sinli dge to dung huydt sau 20 gio nuoi cay.
Ahydrophila co kha nang sinh trucmg tcM (V nhidu moi tnrdng nuox: nuoi khae nhau nhu nuac nhiem phen, phu ducMig va nicM tnrcVng tmng linh. Vc- kha nAng chiu mAn, Ahydrophila co tb^ sinh truong tdt nhat a ncing do mudi 0,5% va cc) kha n.lng gfly bdnh cho ca cr ndng dg mu(")i tir 0,5-1,5%. Vd kha nSng khang khang sinh, 7 chiing vi khuan .'{.hydrophila deu khang hoae khong man cam voi erythromycin va neomycin. Cac chung vi khuan nay tuong d6\ nifin cam \cn gentamycin va rat man cam vcii norfloxacin, sulfamethidazol.
Lieu gay nhiem toi thic-ui la 10'CFU/ml, cac chiing A hydropbyla phiin lap gay chet 50* ca sau khi ngam tir 6-20 ngay, gay nhicni ca b.ing each tiem vi khuan vao phiic mac, ca khong chet va khong co bieu hidn benh.
Tir khoi: A hydrophila, ci. dac dnh sinh Iwc. kliang khang sinh, Udu gay benh.
L BAT VAN DE cay vo triing, cay ria ldn be m i t thach nghidng, diing que cay keo mot durmg tir duoi Idn v i ciy dim sau
vio phan moi truong thach dung. Nuoi vi khuin a Ahydropliyla li vi khuan giy bdnh xuat huyet
hay con goi li bdnh dom do, bdnh nhidm kliuan , ., 4. , . r.., * . , •
* . - u ;, u- u 1' 1 .. ^'. ' r.. L -v nhiet do phong, sau 24h dem ra doc kdt qua.
duong mau, hoic benh la loet tren ca. Benh xuat • «- » . 1
huyet thucmg gap ti'dn cic doi tirong ci nuoc ngot, + Kiem ti-a khi ning sinh Indol: Moi tiuong sir die bidt 0 ci ti-im co bdnh co the giy ra ty Id chet rat ^^ng cho phin ling li moi ti-uong tiyptone waster cao, bgiai doan giong co the ldn den 100% [Ij. Ci bi Diing que cay vo tiling, lay vi klman cay vio b-ong bdnh thuong the hidn mot so dau hidu kem in hoic "^^' tiirdng, nuoi b nhidt do phong. Sau 24h dem ra bo in, noi lo do trdn tang mit, da ci doi miu toi. ^^^ kdt qui bing tiiuoe thu Kovac. Truoe khi bd khong CO inh bae. da ci mat nhat, kho rip, rung vay ^""2 thuoc tinJr co tiid bo sung 1 ml xylen vao ong de 16 da bj xuat huydt. Cic dom xuat huyet mau do nghidm, lie deu de chidt tich indol ldn ldp dung moi xuat hidn trdn thin, cic goc viy, quanh mi?ng. riu ^""^ ^a. Nho 1-2 giot Kovac vio ong nghidm chtia xuat huydt hoic bae ti-ing. fljch nuoi cay, di vii phiit quan sit hien tuong ti-ong
XT U-- ' • .* ^L Ul iL- J- t_ - lop dung moi huu ca.
Nghien cuu nay duoc thuc hi^n vb\ muc dich xac
dinh duoc cic die tinh sinh hpc cua cic chung + ^^^^ ' ^ g catalaza: Vi sinh vat lay tir moi Ahydrophyla phin lip ducyc tir mot so loii ci nuoc truong tiiach miu dit ldn lam kinh sach roi nho HA ngot nhir trim, chep d^ lim ea sa cho eong tic ^^^' ^"'"^ ^^t sau 1-2 giiy.
phong vi dieu tri bdnh. + Kha ning dung huyet tiiach mau: Cay gat vi
L PHUONG PHAP NGHEN CUU khuan ti-dn moi tiirong tiiach m i u cim 5% co bo sung
1. Cic phin ung sinh h6a ampicillin, sau 3 ngiy nuoi ciy. ti-dn dia tiiach mau mpc ldn khuan lac mau ving, tron bong, tao dung -I- Kiem tra khi ning sinh hoi, ldn men duong huy^t theo kieu B.
glucoza vi lactoza bing moi truong KIA (Kligler Iron ,, , , , , Agar): Vikhuin duoc liy tir dia dinh duang bing que , -^ Kha ning phan giai gelatin: moi tiirong thitc
hidn phan ting la gidlatm dinh duong (Nutiient ' Bp Khoa hpc Cong ngh? g^^^tin). Dung que ciy vo tiling liy vi khu&i ttr m6i
74 NONG NGHIEP VA PHAT TRIEN NONG THON • KY 2 - THANG 2/2Qil2
KHOA HOC C 6 N G N G H t i tiirong tiiach dinh duong cay vi khuan bing cich
I dim siu vio moi truong gidlatin, nuoi a nhidt dp phong. Sau 48 gia, chuyen ong nuoi cay vio tii lanh - 4°C, sau 6h dem dpc ket qua phan ung.
2. Phuong phip khing sinh d6
Cic chung Ahydrophila phin lip duoc dinh gii kha ning khing khing sinh voi cic loai khing sinh sau: gentamycin, neomycin, sulfametiioxazol, norfloxacin, erythromycin.
Ting sinh vi khuan trong moi ti-u6ng peptone kiem, nuoi a nhidt dp phong ti-ong 36h roi pha loing vi khuan a nong dp lO'^ vi cay chang ldn b^ mit thach Muller hilton. Dit cic khoanh giay khing sinh ldn be mit thach. Nuoi vi khuan b nhidt dp phong.
sau 24h dpc kdt qua dua vio duong kinh vong vo khuan. Dinh gii tinh khing khing sinh dupe tidn hinh dua theo tidu chuan ciia Clinical and Laboratory (CLSD (2006): Nhay ^20 mm), nhay tiling binh (15-19 mm), khing (<14 mm).
3. Phuong phip dinh gii siic d^ khing cua vi khuin voi cic di^u ki^n mdi truong
Nhidt d6 vi thoi gian: tien hinh nghidn curu thu nghidm khi ning sinh truang vi khi nSng giy dung huyet a cie nguong nhidt dp: 4"C, 18"C, 28"C, 30"C, 37''C. Kiem tra mat dp vi khuan vi kha nang giy dung huyet sau cie khoang thai gian: 4, 8, 12, 16,18, 20. 24, 36,48 gia.
- D6 man: Tien hinh nghidn cuu thu nghidm kha nang sinh truang vi kha nang giy dung huyet a cic nguong dp man: 0,5,1,1,5, 2, 2,5,3, 3,5%o.
Bang 1. Cic die tinh sinh h6a ciia
pH: Ti^n hinh nghidn cuu thir nghidm khi ning sinh tiirong vi khi ning giy dung huyet a cic nguong pH: 5,5; 6; 6,5; 7; 7.5; 8; 8.5; 9.
4. Phuang phip giy nhi^m dOng vit tiii nghidm Dpng vat thi nghidm: ci chep co khoi luang 30 g. khoe manh dupe nuoi trong be nuoi phong thi nghidm. d^ tao su on dinh hon v^ di^u kidn song, cic yeu to moi truong, ngoai canh tic dpng d^n qui trinh song ciia ci so vai ci song bdn ngoii.
Lidu vi khuan giy nhidm: 10^-10" CFU/ml.
- Duong giy nhidm; ngim ci ti-ong vong 2 tieng d^ vi khuan co thai gian tiep xuc vai ci, sau 2 ti^ng, ci dupe lay ra vi cho vio cic be nuoi trong dieu kidn phong tin' nghidm. Hoic tidm xoang phiic mac 0,5 ml/con. Ci doi chung dupe nuoi b be ridng.
Theo doi tridu chiing bdnh, ty Id chet ciia ci sau moi 6 gia, cho den 30 ngiy.
• . K F T QUA VATHAO LUAN
1. Die di^m hinh thii vi sinh h6a
07 chung vi khuan A.hydrophila ducyc phin lip tir ci chep vi ci trim co nghi bi bdnh xuat huydt dom do thu thip a cic dia bin Hi Npi, Bic Ninh, Nam Dinh. Ninh Binh co bieu hidn: boi lpi khong djnh huong. mit loi. rich, cut viy. tupt nhat, tupt viy, mang nhat nhat, co cic cham xuat huyet trdn viy, viing da tupt viy. Giii phau ci co cic bieu hidn bdnh tich: mat sung, dich mat chiia nhieu sic to hong cau; gan, tiian, tim xuat huydt. Phin tich cic die tinh sinh hoa di cho ket qui trong bang 1:
vi khuin Ahydrophila phin lip STT
1 2 3 4 5 6 7
Ky hidu ehung
C1.2 C2.1 C3.1 C3.2 C4 C5 C8
Lac
-1- -1- + + + + +
Giu
-t- -t- -t- -1- + + +
H2S
+ + + + + + +
Gas
-1- + + -1- -1- + +
DD
+ -1- -h -1- + + +
Cat.
+ + + + + + +
Gel.
+ + -t- + + + +
In.
-1- + + + + + +
DH a a a
P
a
P P
(Ghi chii: Lac: lactoza, Giu: glucoza. Gas: sinh hoi, DD: di dpng. Cat: catalaza. Gel: gelatinaza. In.: Indol, DH: dung huydt)
K^t qua trong bang 1 cho thay, 7 chung vi long (hinh Id), Idn men duong glucoza, Idn men khuan Aeromonas da duac phin lip duoc d^ii co duong lactoza, sinh H2S, sinh hoi trdn moi truong :ac die diem hinh thii vi sinh hoa diln hinh ciia loii Kligler Iron Agar (hinh la), catalaza duong tinh, smh A.hydrophila, cu tiie: Ii true khuan gram im (hinh indol (hinh lb), gelatinaza duong tinh (hinh le),
\T), CO kha ning di dpng trdn moi truong thach bin dung huyet thach miu kieu a vi p.
KHOA HQC CbNG N G H |
i " ' . -
• " S I
Hinh 1. Die dilm hinh thii vi sinh h6a ciia cic chung Ahydrophila phin lip
(a) Ahydrophila trdn moi truang KIA; b) Ahydrophila vbi thuoc thu Kovac, c) Ahydrophila
trdn moi truong gelatin 30% de kiem tra boat tinh gelatinaza, d) A hydrophila trong moi truang thach bin long, e) A. hydrophila tren thach miu ; f) hinh
thii te bio vi khuan A. hydrophila
m
»3 XD ZD XO tSD ID
«
0
£4
A.r.ydyopiiyiaCS
2. Xic djnh inh hu6ng ciia cic dilu ki|n nu6i ciy din khi ning smh trudng vi kha ning giy dung huylt ciia vi khuin Ahydrophyla
Khi ning giy b|nh ciia vi khuan phu thuoc lon vio hai yeu to: s6 lupng mam b|nh vi dpc luc cuavi khuin. Muc dich cCia nghidn ciiu niy li tim cic di^u kidn thich hcyp nhat cho su phit trien vi kha nSng gay dung huylt ciia vi khuan Ahydrophila, tao ca s(V khoa hoc dl xic djnh duac didu ki|n thich hop nhat cho vi khuan giy b|nh cho vit nuoi, tii do co cic giai phap quan ly moi truang, ngin ngira tic hai
CLiabenh.
Trong tiii nghipm niy, di lira chpn hai chiing vi khuan Ahydrophila ky hidu C5 vi C8 vi cic phan ling sinh hoa cua cic chung niy manh vi on dmh qua cic lin thuc hidn.
a. Nhidt dp vi thcri gian nudi ciy
Cic chiing vi khuin dupe ting sinh a cac ngucVng nhi|t dd: 4, 18, 28, 30, Sr'C di tim ra nhiet dp thich hop nhat cho su phit trien cua vi khuan. Ca so lira chpn cic ngudng nhidt dp theo cic tii lieu da nghidn ciru truoe diy, vi khuan Aeromonas co kha ning giy bdnh trdn ci dpng vit thuy sin b cic viing hin dai vi nhidt doi. Kit qui nghidn ciiu su anh huong cua nhidt dp din khi ning sinh truang ciiavi khuan li ca so de xic dinh dupe miia giy bdnh. K^l qui theo doi nhidt dp thich hop cho vi khuan the hidn trong bilu do 1.
•TC W 2?
y 430 H)
m
250
ira
10D
so
0
J5D
A.hydrophyla CS
II n CA «l W W Hi I t <8I
Bilu db 1: Anh huang ciia nhi|t dO vi thdi gian din Kit qua theo doi cho thiy, hai chiing vi khuan Ahydrophila diu phit triln dat mat dp cao nhat sau 36 gid nuoi cay d nhidt dp 28''C. Tuy nhidn, d dilu kien nay so lieu thi hidn trong bilu do 1 cung chi ra ring bilu do sinh trudng ciia hai chiing niy tuong doi khic nhau, cu thi: vi khuan Ahydrophila C5 co thdi gian thich nghi li 16 gid, thdi gian sinh trudng (pha log) li tir sau 16 -36 gid, trong do tu 20-36 gid li
» 12ti t h «li 20) 24h J6h ' »
khi ning sinh trudng cua vi khu5n Ahydrophyk-i quing thdi gian duy tri, on dinh su ting trudng ciiavi khuan. Sau 36 gid nuoi cay, Ahydrophila C5 di vao pha suy thoii. Cdn doi vdi vi khuan AhydrophilaO, thdi gian ciia pha tiiich nghi dii hon (20 gid), tdc do sinh trudng cham hon, tuy nhien mat dp vi khuan van dat toi da d 36 gid nuoi ciy, vi mat dp vi khuan tuang duang vdi chiing C5. So sanh bilu do tSng trudng ciia vi khuan Ahydrophila C5 vi C8 cho th^' 76
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 2/
KHOA HOC C 6 N G N G H I
tiieo doi d cic thdi diem 4, 8,12,16,18, 20, 24, 36. 48 Bdn canh nghidn cim anh hudng cua nhic't dp gid nuoi cay thi vi khuan C8 khong co pha cin bing: doi vdi kha ning sinh trucrng cua vi khuan. cung da sau 36 gid nuoi cay. vi khuan dat mat dp toi da. sau tiln hinh dinh gii anh hudng ciia yeu to nay den do so lupng vi khuan giam manh. Tuy nhidn. d ca hai kha nang sin sinh dpc to dung huyet, la ylu to gay chung vi khuan niy, thdi gian vi nhidt dp thich hpp ndn tridu chiing xuat huydt d ca. Ket qui thi hidn nhat cho sir phit trien tuomg ung li 36 gid vi 28"C. trong bang 2.
Bang 2. Anh hudng ciia nhidt dd v i thdi gian din k h i ning giy dung huylt ciia vi khuin Ahydrophila C5 vi C8 Thdi gian (h)
4 8 12 16 18 20 22 24 36 48
4
C8 C5
18 C8 C5
+ + + + + +
28 C8
+ +
-1-
+ +
C5
+ + + + + + + + +
30 C8
+ + + + + +
C5
+ + + + +
-1-
+
37 C8
+
-1-
+ + + +
C5
+ + + + + + +
Ghi ehli: (+): co dung huyet p; (-): khong dung huyet O 4°C, vi khuan mic du eo phit trien (bieu do 1) nhung khong sinh dpc to dung huylt. Kit qua niy cung tuong tu vdi vi khuan sau nuoi cay 4 gid. O nguong nhidt dp tir 18-37°C, c i hai chiing vi khuan deu sin sinh dpc to dung huylt sau 20 gid nuoi ciy.
Tuy nhidn, chung C5 t h i hidn kha ning sinh dpc to dung huylt manh ban, cu till: sau 8 gid nuoi cay d nhidt dp 28°C, vi khuan niy d i sin sinh dpc to, trong khi dd, ehung C8 thi chi sin sinh dpc to sau 18 gid. G nhidt dp 18*'C, vi khuan C8 khong sin sinh dpc to dung huyet cdn vi khuan C5 lai sin sinh ylu to niy sau 18 gid nuoi cay.
Tir kit qua d bilu do 1 v i bang 2 ed thi k i t luan ring: hai ehung vi khuan Ahydrophila C5 vi C8 cd khi ning giy bdnh cho c i vio miia he trong nim.
- pH: Loii vi khuan Aeromonas dupe xic dinh li nguydn nhin giy bdnh xuat huylt trdn c i nuoi d nhilu viing dia ly khic nhau. Hai chung vi khuan Ahydrophila C5 v i C8 dupe ting sinh trong cic moi trudng peptone cd dp pH li: 5,5, 6,0, 6,5, 7,0, 7,5,
khi ning phit trien tot ban d moi trudng axit nhe den trung tinh, con chiing C8 lai die bidt thich nghi vdi pH kiem nhe (8,0-8,5). Thuc te 2 chung vi khuan nay dupe phin lap tir hai viing khic nhau, chung C5 dupe phin lap tir mau c i bdnh nuoi tai Bic Ninh, con chiing C8 phin lip tir cic bdnh nuoi tai Nam Dinh.
Co Id, chinh vi ylu td dia ly da lim ndn die tinh thich nghi vdi yeu td pH cua hai chiing niy.
Bilu d6 2. Anh hudng ciia pH tdi kha ning sinh trudng ciia Ahydrophyla
- D6 min (NaCI)
Theo cic tii lieu nghidn cuu cua tic gii Robert, 8,0, 8,5 9,0 d 28<'C/36 gid di x i c dinh pH thich hop jggg [4] tiii vi khuan Ahydrophila co kha ning giy nhat cho su phit triln cua vi khuan. Kit q u i theo j^gj^j^ ^j-dn c i dpng vit nudc man, nudc la vi nudc doi pH thich hpp cua vi khuan dupe till hidn trong j^gp^ DQ ^Q ^^ tim ra dp man thich hpp nhat cho su bilu do 2. sinh trudng vi phit trien cua cic chiing phin lip, Theo doi sau 24h nuoi cay d 28''C cho thay, hai ti'ong nghidn cim niy da khio sit su sinh tiirdng v i chiing Ahydrophila cd kha nang tiiich nghi tuang phit triln cua vi khuan d cic nong dp muoi: 0,5, 1, doi khic nhau ddi vdi ylu td pH, cu till: chung C5 co 1,5,2,2,5, 3,3,5%.
KHOA HOC C 6 N G N G H £
Thi nghidm dupe tiln hinh nhu sau: ting sinh vi khuan trong moi trudng peptone co cac ndng dp mudi nhu trdn d nhidt dp 28"C. Kit qua theo dPi dupe till hidn trong bilu do 3.
Bilu dd cho thay dp man thich ha|i nhat cho cic chiing vi khuan thi nghidm sinh tnrdng li 0,5%. dat khoang 8x10" CFU/ml sau 36h nuoi ciy d 28"C.
Ndng dp mudi cing cao thi kha ning sinh trudng ciia vi khuan cing giam. O ngudng 1% vi 1,5% kha ning
sinh trudng cua vi khuin giam di ding kl, dat khoing 3x10'' CFU/ml sau 36h nudi cay. Tilp tuc ting ndng dp mudi ldn de dat dp min ciia nudc la vi nudc min thi khi ning sinh trudng cua vi khuan giim din vi thap nhat d ndng dd mudi li 3 - 3,5%.
Vdi sir phin tich d trdn, ta thiy vi khuan Ahydrophila cd thi sinh tnrimg tdt nhat d moi tnrdng nudc ngpL Tuy nhidn, theo nghidn ciru trude diy cua chiing toi [2], vdi mat dp vi khuan li 3x10^ CF'U/ml d dp min li 1% -1,5% thi vi kliuan niy hoin toin cd khi ning giy bdnh cho ci d moi trudng nudc la.
Bang 3. Khi ning khing khing sinh
Bilu dd 3. Anh hudng cua dO min din khi ning sinh trudng cua Ahydrophyla
3. Khi ning khing khing sinh
Trong thi nghidm niy, di dinh gii kha nSng khing khing sinh cua vi khuin phin lip vdi cac loai khing sinh hidn dang duoc sir dung trdn dpng v£it thiiy sin li: erothromycine, gentamycine, neomycine, norfloxacin, sulfamethidazole. Kit qua thir nghidm khing sinh dupe thi hidn trong bang 3 vi huih 2.
cua cic chiing Ahydrophyla phin lip Khing sinh
Erythromicine Gentamycine Neomycine Norphloxacin Sulfamethidazole
C1.2 I I I S S
C3.2 R S I
s s
C4 R S I
s s
i.it qui C5
R S I
s s
C8 R S I
s s
C2.1 I I I S S
C3.2 S S I
s s
S: Nhay ^20 mm), I: Nhay tiling binh (15-19 mm), R: Khing (<14 mm).
Gonib
Ewifcrt»"5' fUa
•'•j HoitoAf^un.
t
Hinh 2. Kha ning khing khing sinh cua vi khudn Ahydrophila C5
Dinh gii trdn ca 7 chiing vi khuin Ahydrophila ^^h tiiich ting tiirdng. Tir kit qua nay co till k^t phin lip dupe, di nhin tiiiy cac chiing diu khing ^^^^ ^a bp: cac khing sinh co hidu luc dimg ti-ong hoic khdng man cam vdi khang sinh erythromycin ^i^" trj b|nh xuat huylt dom dd do vi khuan vi neomyem. Cic chiing vi khuan nay tirang ddi man ^.hydrophila la norfloxacin, sulfametiiidazol.
cam vdi gentamycin vi rat man cam vdi norfloxacin, sulfamethidazol. Thuc tl, cic chung vi khuan Ahydrophila ducyc phin lip tir ci nudi tai cic trang trai nudi ci, vi viy, trong qui trinh nudi tha, it nhilu cd su dung khang suih vdi muc dich phdng bdnh vi
4. Kha ning giy b^nh cho c i chdp ciia chiing vi khuin phin lip
Theo nghidn cim ciia EGUSA, 1978, vi khuan Ahydrophila gay bdnh cho ci nudc ngpt vdi trieu chimg diln hinh la xuat huylt vi hoai tu npi quan.
78
NONG NGHIEP VA PHAT TRIEN NONG THON KY 2 - THANG 2/2012
KHOA HOC CdNG NGHfi Trong nghidn ciiu ve bdnh hpc, ngudi ta di xic dinh
dupe kha ning bi bdnh ciia vit nudi phu thupc vio cic ylu td: mdi trudng sdng, mam bdnh, dpc lire vi ca thi vit ehu. Khi 4 ylu td niy giao thoa vdi nhau sd tao ndn tinh trang bdnh ly.
Thi nghidm khi ning giy bdnh cua vi khuin Ahydrophila ducyc tiln hanh nhu sau:
+ Ld ddi chung am: ci nudi d cic dilu kidn chim sdc binh thudng.
+ Ld TNI: ci dupe tidm canh khuin Ahydrophila mat dp 10^-10^ CFU/ml vi nudi d cic dieu kidn chim sdc binh thudng. Theo doi ci trong 30 ngiy.
+ Lo TN2: cic duoc ngim canh khuan Ahydrophila, mit dd 10^-10'' CFU/ml vi nudi d cic dieu kidn chim sdc binh thudng. Theo ddi ci trong 30 ngiy.
Ci dupe giy nhidm bing phirong phip ngim vdi 02 chung vi khuan Ahydrophila cd mat dp tl bio vi khuan nhu trdn cho thay: chiing C5 cd kha ning giy bdnh nhanh ban, giy chet 50% ci trong 6 ngiy sau giy nhidm, vdi lieu giy chit tdi thilu li 10^ TB/ml; cdn chung C8, Cling vdi cimg Ueu giy chit tdi thilu li 10^
TB/ml nhung din 20 ngiy sau giy nhidm mdi giy chit 50% ci thi nghidm. Ci bi bdnh cd hidn tupng xuat huylt, gdc viy xuat huyet, tupt vay, tupt nhdt, khi giai phiu ci thay mat sung, rudt khdng chiia thuc in, bong bdng cang phdng, mang nhcrt nhat, tiet dich nhieu.
Hinh 3. Ci chit do nhilm vi khuin Ahydrophila C5 Bdn canh dd, dudng giy nhidm cung anh hudng din kit qua giy bdnh tren ci. Khi giy nhidm ci bing cich tidm vi khuan vio phiic mac, ci khdng bi chit, dieu niy cd fhl Iy giai do khi vi khuan tan cdng vio ca thi vat chii qui trinh dip ling midn dich xiy ra, cic te bio dai thuc bio nim d Udn vong ndi mo se nhin dang vi tidu didt phan nio tic nhin giy bdnh, din tdi kit qua Ii vi khuin hoic khdng cdn hoic cd mit dd khdng dii dl giy bdnh.
IV. KET LUAN
7 chiing vi khuan Ahydrophila dupe phin lap tir ci chdp, trim ed d khu vuc ddng bing Bic bd cd die tinh sinh hda diln hinh cua loii, dd li: cd kha ning di dpng, ldn men dudng glucoza, lactoza, sinh H2S, sinh hoi, sinh indol, catalaze duong tinh, gelatinaza duong tinh, dung huylt thach miu kilu a vip.
Hai ti-ong sd 7 chiing Ahydrophila C5 vi C8 dupe sir dung dl nghidn cuu die tinh tiiich nghi cho thay: ci hai chiing diu li vi khuan ua am, thdi gian vi nhidt dp thich hpp nhat cho su phit triln tuong img li 36 gid vi 28°C, d khoing nhidt dp tir 18-37«C, ci hai chiing vi khuan deu sin sinh dpc td dung huylt sau 20 gid nuoi cay.
Cic chiing Ahydrophila phin lip cd khi ning sinh trudng tdt trong dii pH tir 6,5-8,5.
Cic chiing Ahydrophila phin lip cd thi sinh trudng tdt nhat d moi tiirdng nudc ngpt Tuy nhidn, vdi mat dp li 10^ CFU/ml d ndng dp mudi tir 1-1,5%
cho thay vi khuan niy hoin toin cd khi ning giy bdnh cho ci d moi trudng nudc la.
7 chiing vi khuan Ahydrophila deu khing hoic khong min cim vdi erjdhromycin vi neomycin. Cic chiuig vi khuan niy tuong ddi man cam vdi gentamycin vi rat min cim vdi norfloxacin, suUamethidazol.
Vdi lieu giy nhidm tdi thilu li 10^ CFU/ml, giy nhidm bing phuong phip ngim, hai chiing Ahydrophila C5 vi C8 giy chit 50% ci sau 6-20 ngiy, giy nhidm ci bing cich tidm vi khuan vio phiic mac, ei khong bi chit vi khdng cd bilu hidn bdnh.
TAI UEU THAM KHAO
1. Phan Thi Vin, Pham Thi Ydn, Tran Thi Kim Chi, Nguydn Thi Hi, Pham Vin Khang, Nguydn Thi Nguydn, Pham Vin Thu, Kim Vin Van, 2003. Nghidn ciiu xic dinh tie nhin giy bdnh ddm do vi bdnh xuat huylt trdn ci trim cd. Tuyln tip bio cio khoa hpc vl nudi trdng thuy sin tai hdi nghi khoa hpc toin qudc Ian tiiir 2 (24-25/11/2003). Nhi xuat bin Ndng nghidp, 2003. Trang 521-524.
2. Pham Cdng Hoat, Pham Thi Tim, I^ Vin Nhuong, 2011. Xic dinh mpt sd ddc td giy bdnh ciia
KHOA HOC C 6 N G NGHfi
vi khuan Aeromonas hydrophila phan lap dupe tir e i 4. Roberts R. J., 1989. Fish Pathology, Bailliere chep bi bdnh xuat huylt ddm dd d khu virc ddng Tindall, Ix)ndon, Second edition,
bing Bic bp. Tap chi Nong nghidp vi PTNT, sd 4. 5 7,^^^^.^ j ^ Delamare A P., Costa S..0., 3. Erova T. E., Sha J.. Horneman A. J.. Echeverrigaray S., 2009. Diversity of exti-acellular Borchardt M. A . Khajanchi B. K.. Fadl A A, Chopra p^teases among Aeromonas determined by A. K., 2007. Identification of a new hemolysin from I T 1 TA i- J »*• 1 . ,
, . , , . . ^ „ , . ^ . , , , ., zymogram analysis. Journal of Applied Microbiology
diarrheal isolate SSU of Aeromonas hydrophila. "•' FEMS Microbiol. U4t. 275(2):301-11. ^'^'"'"^ 1^9, Issue 1, page 212-219.
DEFINE THE CHARACTERISTICS OF Aeromonas hydrophila ISOLATED FROM INFECTED FISH IN RED RIVER DELTA
Pham Cong Hoat Summary
The biochemical characteristics has been defined from 7 strains of Ahydrophila isolated from infected fish in Red river delta show typical of species that is motion, fennentabon of glucose and lactose, H,S, indol and gas producing, catalasc positive, gelatinase-positive, a and (3 haemolyUc type. Two of the seven Ahydrophila strains nained C5 and C8 are used to study the adapbve characteristics showed that both of selected bacterial strains are preferred wami, time and temperature most suitable for growth respectively 36 hour and 28"C. at temperatures range between IS-Sy^C. baemolytic toxin can be produced after 20 culture hours. Ahydrophila able to grow well in acidification. eutrophicaUon and neutral water environment. For salinity tolerance, Ahydrophila can be growth well at salt concenU-ation of 0.5% but at 1- 1.5% of salt concentration, selected of Ahydrophila can cause disease in fish. Regarding antibiotic resistance, seven Ahydrophila strains were resistant or not susceptible to erythromycin and neomycin.
The bacteria are relatively sensitive to gentamycin and very sensitive to norfloxacin, sulfametbidazol.
Minimum infectious dose is 10^ CFU/ml. strains of A hydrophila isolated fish kill 50% after soaking from 6- 20 days, no fatal or infected of experimental fish by injecting A. hydrophila to peritoneum.
Keywords: A hydrophila, fish, biological characteristics, antibiotic resistance, infectious dose.
Ngudi phan bi^n: TS. Hi Ky
