Tap chi Cong nghe Smh hoc 11(1): 153-159.2013
K H I KCH DAI \ L N G T R I N H TL I 6 S rDNA t).\C H I E U NH W l P H A T H I E N STREPTOCOCCUS SL IS TRO\i^ M,AU M A U
Lam Tuan Thanh, Ngd Thj Hoa
Tnmg ldm v hpc nhiei dai, Dem vi nghten cuu ldm sdng Dai hpc Oxford. Benh vien Benh nhiel dai Thdnh pho Ho Chi Mmh
TOM TAT
Streptococcus suis IS suis) la vi khuan co hdi tren heo Gan day. S siiis duoc biet den la lac nhan mdi ndi gay benh cho ngudi do lay nhiem lir heo. Sd ca benh tren nguoi dirge bao cao gia tang tren toan the gioi. nhat la t?i cac nudc Chau A. Chan doan nhiem .S. suis tren ngirdi hien nay thuong dua vao kv ihuat cay va phan lap VI smh hoac cac khuech dai DNA dac hieu ciia serotype 2 lu mau benh pham Phuang phap PCR khuech d.ti viing Irinh tu 16S rDNA dac hieu cua 5, suis trong mau mau da dugc lien hanh khao sal Ngudng phat hien v.idii dac hieu ciia phan iing duoc xac dinh nham danh gia kha nang ung dung trong phal hien nhiem 5 suis Mau mau cua 521 heo benh do nhiem vims gay hdi chung rdi loan smh san va hd hap (benh lai xanh) cQiig dugc khao sat linh hinh ddng nhiem cua S suis. Ket qua cho thay, phan img khuech dai cd do dac hieu cao va ngucmg phat hien dat25 han sao/phan img su dung DN \ ly Irieh tu mau mau. Co I0.6"i, heo benh lai vanh hi ddng nhiem vdi S .suis duoc xac dmh. Ket qua nghien cuu cho thay tinh img dung cua phmmg phap trong clian doan nhiem S .suis tren heo va ngudi
Tir kluia: I6S iD\ ), ddng nhien PCR, .Streptococcus suis
xanh hoi ihini I loc 1 il lid Imp, ngiriing phal luen
GIOI THILU
Streptococcus suis fS suis) la indliac nhan gay benh phd bien tren heo va la tac nhan gay benh quan trgng cho ngudi Idn, chu yeu tai cac nudc chau A.
Ddi tuning nguy ca lay nhiem la nhiTing ngudi thudng xuyen licp xiic vdi heo nlm ngudi lain cdng tac ihii y. chan nudi, giet md, v.i che bien thil hcohay iieu ihu san pham cua heo cd nhiem khuan (Nghia ei al.
20M. Slaats et al. 1997; Lun el ai. 2007) Tai \ i c l Nam. 5 ,s(//.s serotype 2 duoc xac dmh la mdl trong nhfrng tae nhan hang dau gay viem mang nao mu a ngudi ldn(Mai el al, 2008. Wertheim el at. 2009)
Nudi cay vi sinh, phan lap va dnih danh bang cac phan ling sinh hda van duac xem la ticu chuan vang irong chan doan nhi^m S suis Tuy nhien nhieu Irudng hop benh dien hinh nhung nudi cay khdng Ihanh cdng, mgl trong nhiing nguyen nhan la do benh nhan (hoac heo benh) da dugc dieu tribang khang sinh trudc dd. Trong mdl sd trudng hgp.phuong phap khuech dai doan DN \ trong chan doan nhiem S suis serotype 2 trong mau dich niio liiy dti gliip xac djnh tac nhan gay benh trong trucmg hgp that b^i Irong nudi cSy (Wertheim ei al.. 2009.
\I.ii Cl ai. 2008). Tuy nhien. chdn doan bang phuang phap smh hoc phan tu nhu Iren chu \eu duac ihuc hi?n nham phal hien S suis serotype 2 iren benh
nhan do day lii scioiype chinh g;iy benh iicn nj Ngoai serotype 2. cac truimg hap benh nhan nl S sins seiolNpc 14 va 16 cimg da duac bao (Goltschalk el cd. 2007. \ g h i a tv <//. 20IIS) .V gay benh cho heo thudc nhicu serotype khac ma chu yen la cac serotype I- 9(Gollschalk e.
2007). MaiQis \a ddng lac gia (2004) phat phirong phiip PCR khuech dai innh lu gene rON.Adc phal hien S suis lir mju amidan hen
De phal hien su hien dien cua S suis trong mau, chung tdi khao sal kha nang img dung p|- phap khuech dai doan DNA dac hieu cua gen rDNA cho S suis Kha nang img dting cua qui trong xac dmh nhiem S suis irimg mau mau cu benh thu nhan lai mdt Tmh ihudc ddng bang Cuu Long cdng duac khao sal
Incn I6S
i r i m g I6S irinh heo
NGUYEN ULL NGHIEN C U
VA PIILONG
Chung S. suis s e r o t \ p e 2
Chung .V SUIS serotype 2 lATtC 31'''i'5) duac dimg lam chung ddi chmig irong loan bd tin nghiem
\ i khuan S w//- ( \TCC 3 15.33) duuc iJU'j Muh Ir.mg canh tnrong B!ii 6 gio o ''•'iX Nong do \i kliii.in duoc xac dmh bang cach d a n kluian l.ic IKH dii
Lam Tuan Thanh & Ngd Thi Hoa thach mau ciru theo phuong phap dia nho gigt (Chen
et al.. 2003; Sieuvverts et ai. 2008), MSu DNA ctia cac chiing vi khuan ddi ehiing
M^u DNA cua 5 suis thudc 34 serotype cdn iai dugc cung cSp boi GS Gottschalk, Dai hgc Montreal, Canada Ngoai ra DNA ciiacac chung vi khuan khac cung duac diing nham khao sat tinh dac hieu ciia cap indi, bao gdm cac vi khuan Gram am Escherichia colt, Pasleuretta miiltoctda. Shigella, Salmonella, Klebsiella pneumoniae (ATCC700603), Acinelobacier sppvk Pseiidomonas aeruginosa: cac chung vi khuan Gramduong; Sireplcocciis pneumonia (ATCC496I9), Slaphylococciis aureus khang Methylcyline (MRSA) (ATCC25923) va Staphylococcus aureus nhay Vlethylcyline (MSSA) (,ATCC33591)
Mau mau heo benh
Mau mau khdng ddng cua heo benh dugc thu nhan hi cac hd chan nudi trong mdt Tinh dang cdng bd dich tat xanh trong nam 2010 Cac heo benh cd ineu chiing dien hinh nhu, ha. khd tho, nhip thd nhanh, bd an, da bung va da tai tim, sdt, heo nai xay thai va thai luu Tat cacac trai heo dugc lay mau d Iren da duoc xac nhan nhiem tai xanh bang phuang phap real time PCR phien ma nguac (Xiao el al, 2008).
L> trich DNA va khucch dai PCR 16S rDNA dae hieu e h o ^ . suis
Mau sinh khdi cua tiing vi khuan dugc ly tam thu nhan tii' Iml canh tnrdng nudi cay sau 16-20 gid.
DN.A cua tirng vi khuan duoc ly trich sir dung kit Qiamp DNeasy Blood & Tissue Kit (Qiagen. Vuong Qudc Anh) vii theo hudng dan cua nha san xuat, Nham muc dich tten hanh phan img khuech dai vdi DNA cua S suis serotype 2 dugc lytrich tir mau mau. 1 ml dich nudi cay qua dem cua5 suis serotype 2 duocly tam thu nhan smh khdi sau dd hda vao 1ml mau cuu vd triing va Hen hanh ly trich DNA bang kit Qiamp DNA Blood Midi (Qiagen - Anh)
DNA cua S suis (ATCC 31533) dugc dimg nhu chimg duang. DNA cua S suis thudc 35 serotype dtrgc diing nhu mau can khao satva nudc cat vd triing duac diing trong mau chimg am.
Doan trinh tu 16S rDNA kich thudc 318 bp dac hieu cho5 Suis dugc kliudch dai sii dung bang cap mdl I6S-F.5'-CAGTATTTACCGCATGGTAGATAT-
3 \ a 16S-R: 5-GTAAGATACCGTC AAGTGAGAA-3' (Marois el ai, 2004). Thanh phan phan iing PCR bao gdm IX buffer, 2 nM MgCL, 0 2 pM dNTPs, 0.2 pM mdl xudl (16S-F), 0 2pM mdt ngugc (I6S-R), va I 25U Taq polymerase, Chuang trinh luan nhiet PCR tren may Thermocycler (Eppendorf, Dire) bao gom cac budc; 95''C 5 pluit. sau do la 40 chu ky lap lai vdi cac budc: 95"C I phiit, 5 8 ^ / 1 phut va 72"C/I phiit, sau ciing la 72"C/5 phiit.San pham khuech dai CLia phan ting PCR dugc kiem tra tren gel agarose 1.5%.
Xac dinh ngu'&ng phat hien ciia phirong phap DNA ciia S. suis serotype 2 dirge pha loang bac 10 vdi ndng do vi khuan trong khoang 10^ den 10** va pha loang bac 2 vai ndng dp vi khuan trong khoang 10"' den lO' thanh day cac ndng do khac nhau Tai mdl ndng do pha loang phan iing PCR dugc lap Iai 5 Ian. Ndng do thap nhat cho ket qua duang tinh o ca 5 lan lap lai dugc xem nhu nguong phat hien (Charles eiai, 2011)
T i n h d a e hieu ciia eapmdi khuech dai doan DNA dac hieu 16S rDNA cuavi khuan S. suis
Tinh dac hieu cua cap mdi dugc khao sat vdi DNA cua S suis thudc 35 serotype va DNA ciia cac chung S SUIS thudc nhdm "nhieu serotype khac nhau", day la cac chung cho ket qua huyet thanh hoc, diing de xac dinh serotype, duong tinh vdi nhieu huyet thanh cua cac serotype khac nhau, phan lap tir amidan heo (Chieu et al ,2011) Ngoai ra, phan irng cting dugc thuc hien vdi DNA ciia cac chung vi khuan thudng dugc phat hien trong mau amidan heo Ket qua cho thay phan ung da khuech dai duoc san pham dac hieu vdi vach san pham kich thudc khoang 318 bp tir DNA cua tat ca cac chung S, sidssu dung Irong nghien ciru (Hinh I).
Kel qua khuech dai I6S rDNA dac hieu cho S.
SUIS sir dung khudn mau DNA ly trich tir 10 chiing vi khuan Gram am va Gram duong khac S suis deu cho ket qua am tinh (Hinh 2A) Trong khi dd, kel qua khuech dai sir dung DNA ciia nhimg mau vi khuan Gram duong va Gram am tren nhung da dugc them DNA cua S. .suis serotype 2 deu cho ket qua duong tinh (Hinh 2B)-
Tap chi Cdngnghe Sinh hoc 11(1); 153-159. 2013
Hinh 1. San pham khuech dai doan DNA 16S rDNA dac hieu ciia S. suis vai DNA cua cac chung vi khuSn M, thang chuan 100 bp (New England Bioiabs) GiSng 6 va 14 DNA cua cac chung fulelhicilline Resistant Stapbytococcus Aureus (MRSA) Cac gi^ng cdn lai la DNA cac chiing S suis v6i cac serotype khac nhau. cu I h l G i l n g 1-5 serotype 15.16 28 (chung nay cho k l l qua d u o n g tinh vdi ca 3 loai huyet thanh dmh serotype 15.16 va 28); serotype 12: serotype 25. serotype 33 serotype 9,31, G i l n g 7-13 serotype 15,20; serotype 1, serotype 3. serotype 13: serotype 26, serotype 16 28. serotype 1.12.
Gieng 15-18 serotype 16; S, su's serotype 6, serotype 8 va serotype 14
Hinh 2, San pham khuech dai gen 16S rDNA dac hieu cho Streptococcus sois t u cac m i u DNA ciia vi khu^n Gramduong va Gram am khong co chii'a (A) va co chu'a DNA cua S suis (B) GiSng 1,2 S suis serotype 2, 3 E coli. 4 Acinelobacter 5 Staphylococcus aureus; 6 Salmonella, 7 Streptococcus pneumoniae. 8 Pseudomonas aeruginosa. 9 Pasleurella multacida. 10 Klebsiella. 11. MRSA; 12" MSSA,13 chu'ng am M thang chuan 100 bp (New England Bioiabs)
Nham muc dich khao sal kha nang irng dung phmmg phap khuOch dai 16S rDNA dac hieu cua S suis trong chan doan nhiem trimg S, suis ircn heo, chiing ldi lien hanh phan iing PCR su dung mau DNA dugc ly trich lir mau mau ciruda duac ihem chung vi khuan S. suis (ATCC 31533) K a qua cho Ih^y san phSm PCRla doan DNA 318 bp ciia gen 16SrDNA dugc khiidch dai dac hicu (Hinh 3),
Hinh 3, SAn p h i m PCR khuech dai 16S_rDNA ciia S suis serotype 2 sir dgng DNA ty Inch lii- mau mau G i l n g 1 DNA ly trich l u mSu mau cb chua S. suis serotype 2 Gilng 2. mSu mSukhdng c6 chira vi khu^n S suis G i l n g 3 Ihang c h u i n 1Kb plus (Invilrogen)
Ngudng phat hien cua phan ting
Tir dich huyen phu nudi cay ban dau, ndng do vi khudn S Suis duoc \ac dmh khoang 5x10*' CFU/ml bang phuong phap nhd gigt, DNA dugc Iy trichtu dich nudi cay va tir mau ciru. sau dd tien hanh pha loang bac 10 va bac 2 theo day ndng do va duoc diing iam khudn mau trong phan img PCR.Ket qua cho thay phuang phap PCR phat hien dugc 5 .v»Avtai tat ca ndng dd > 15 vi khuan trong mau dich nudi cay va 25 vi khuan irong mau mau trong ca 5 lan lap lai (Bang 1. Hinh 4), Tuy nhien. phuang phap PCR cdng cd the phat hien dugc 2 vi khuan trong mdt phan img vdi man DN.^ K trich tir dich nudi cay va 3 vi khuan \di mau DN.A. h trich tu mau mau
Tlieo Charles \ a ddng tac gia. mot phan ung PC R cd .'^ lan lap lai tren timg mau cua day ndng dd khac nhau. chl can mdt ket qua am iinh iren 5 lan lap lai thi xem nhu cd \ac suat phat hien ducmg linh dudi 50% \di dd tin ca\ 95% (Charles ei al. 20111. Vi va\ ngudng phat hien cd dd nhay IOO"., va \di dd tin cay 9 5 % se dugc chon la ndng dd 15 hay 25 ban sao ciia bd gen cua S. suis ly irich lu dich nudi cSy hay lu mau mau.
Lam Tuan Thanh & Ngd Thi Hoa
Tuy nhien, theo tai lieu cdng bd cua To chiic Thii y The gidi (World Organization for Animal Health - OIE (Office Interbational des Epizooties)) nguong phat hien ciia phuong phap, hay cdn ggi la do nhay phan tich, la ham luong miic Ueu thap nhat trong mau thu ma phuong phap cd the phat hien vdi mgt do tin cay nhat dinh. Vdi phuang phap PCR chan
doan dugc xac dinh d nong do ma tai dd sd lan cho ket qua duong tinh la tdi thieu 50% tren tdng sd lin lap lai (Td chiic Thu y The gidi, 2009) Nhu vay theo tieu chuan ciia OIE, ngudng phat hien ciia phuong phap khuech dai gen 163 rDNA ctia S. suis la 2 va 6 ban sao ciia bd gen ciia vi khuan dugc ly trich tir mau dich nudi cay hay mau mau.
Bang 1. K l l qua cua 5 l l n lap lai cua phan i i n g khuech dai 16S rDNA ciia Streptococcus suis D N i ^° liFO-ng S, su/s t r o n g mot phan ipng v d i n d n g do vi k h u a n pha loang giam dan Dich 1,510^ 1.5,10'"" 1,5.10^'" 1,5.10"" 15'^* ?'*"
Ghi chu:# N6ng do ban d i u ciia dich nuoi c i y - 3 x 1 0 , S N6ng do ban d^u cua S. surstrong dung dich mau c i r u . - 5 x 1 0 (a). Cac mau d u o c pha loang bac 10 tii' nong dd trifoc, (b) Cac m l u duo'c pha loang b | c 2 iLr nong do tripoc, +, kel qua PCR d u o n g tinh, - k l l qua PCR am tinh.
Hinh 4. San pham khuech dai PCR (318bp] cua gen 16S rDNA ciia S, suis voi DNA ly Inch tir dich nuoi cay (A) hoac tir m l u mau (B) G i l n g 1-8 S6 lirong vi khuan trong tiing phan u'ng giam dan l u o n g i m g vdi ndng do S suis trong miiu (nhu*
liet ke trong bang 1) Hinh A G i l n g 1-8 tuong ii-ng vai ndng do S suis la 1 5 10^ 1 5 1 0 \ 1 5 10^, 1.5 10^ 15, 7, 4, 2 Hinh B Gigng 1-8. nong do S. SU'S la 2,5.10^ 2,5 10', 2 5. 1 0 \ 2.5 10^ 25, 12. 6 va 3 (-) chu'ng am udi m l u DNA dugc thay b i n g nuoc c i t vo triing: M: thang chuan lOObp
I i le nhicm S. suis trong man heo nhiem virus gay hdi chiing sinh san va hd hap trong nam 2010
521 mau mau heo benh cd tneu chirng Iam sang cua hdi chimg rdi Ioai sinh san va hd hap (Porcine Reproductive and Respiratory Syndrome (PRRS).
benh tai xanh), duac thu nhan tix 103 hd chan nudi da duoc xac nhan nhiem virus PRRS bang phuong phiip real lime RT-PCR (Xiao el at., 2008). Nham tim hieu li le bgi nhiem ciia S sins tren heo benh tai xanh, chiing tdi img dung phuang phap khuech dai trinh tu 16S rDNA dac hieu cua S suis trong cac mau DNA phan lap tir mau mau cua heo benh, Tdng cgng 55 (10,6%) trong sd 521 mau mau heo benh tai xanh cho ket qua duong tinh vdi S suis. Ket qua khang dinh 10.6% heo benh tai xanh hi ddng nhiem
\di S suis
THAO LUAN
S suis la VI khuan ca hdi phd bien trong cac ca quan hd hap ciia heo Co it nhat 4 1 % heo khde Irong cac ca sd giet md tai cac Tinh thanh phia nam Viet Nam cd mang vi triing nay vdi cac serotype khac nhau tren amidan (Chieu el al ,2011) Mac dii S. suis serotype 2 dugc xac djnh la serotype gay benh chii yeu cho ngudi va ddng vat, S. suis serotype 14 va 16 ciing da dugc canh cao la tac nhan gay benh cho ngudi va cac chiing thugc serotype 1-9 cung la cac serotype phd bien gay benh cho heo (Nghia el at., 2008; Gottschalk el al., 2007) Phat hien va dinh danh S, suis bang phuong phap nudi cay vi sinh chira kha thi de img dung cho chan daan va tSm soat benh hay mang triingtai tat ca cac Benh vien hay Chi cue
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Tap chi Cong nghe Sinh hoc 11(1) 153-159. 2013 Thu y do chi phi cao, mat thdi gian va bj anh hudng do su dung khang sinh trudc khi m l u benh pham dugc thu nhan. Do vay. mdt qui trinh PCR nham phat hien nhanh tat ca cac serotype ctia S suis nham img dung trong chan doan va tam soal tinh hinh mang triing tren heo la dieu can thiet. Phuong phap PCR dugc md ta trong nghien ciiu nay khuech dai doan DNA kich Ihudc 318bp thudc viing trinh ty 16S rDNA cua S. suis (Marois el ai, 2004),Trinh tymuc tieu thudc viing VI-V2 cua gene I6S rRNA ciia S suis la viing cd do bao tdn cao nhat cho Ioai S. suis vi la viing cd it bien di di truyen nhat ddi vdi gen I6S rRNA (Chakravorty et ai, 2007). Bg mdi cung dugc kiem tra in-silico vai tat ca trinh tu cua doan I6S rDNA hien cd tren ngan hang dir lieu cdng nghe sinh hoc qudc gia (National Center for Biotechnology Informantion - NCBI) bao gdm ca trinh tir eiia 35 serotype cua S suis ciing cac trinh tu 16S rDNA ciia cac loat VI khuan khac de bao dam dd dac hieu trudc khi trien khai nghien ciru
Theo Chatelher va ddng tac gia, dd tuong ddng ve trinh tu t6S rDNA d giii'a cac chung thudc ciing loai S SUIS la tir 93,94% den 100%, cao hon nhieu so vdi cac Ioai khac nhu Burkholderiasotanaeearum va Aerococcus urlnae, Tuy ket qua phan tich cay phan loai dua tren trinh lu 16S rDNA cho thay S suis serotype 32, 33 va 34 tuong ddng vdi cac loai khac thudc gidng Slreplococeus hon la cac serotype khac cuaS Suis nhung chung chua tach han khdi loai Slreplococeus suis(Chale\\\tr el ai. 1998). Khac vdi kk qua thu dugc tir 16S rDNA, nhirng nghien cim phan tieh va so sanh trinh tu gene chaperonin 60 cua cac serotype 5 suis va cac Ioai kliac thudc gidng Streptococcus cho thay dp tuang ddng rat cao giua S suis serotype 32 va 34 vdi Streptococcus onsralli va ddng thdi cung cd su khac biet rd rang giira 2 serotype nay so vdi cac chiing S suis Ihudc cac serotype khac (Hill et ai, 2005). Tuy nhien cho ddn nay van chua cd nghien ciiru khac khang dinh su khac biet ciia cac chung thudc S suis serotype 32 va 34 vdi cac serotype khac ciia S. suis, do vay trong nghien ciru nay chiing tdi su dung phuang phap PCR 16S rDNA nham danh gia kha nang phat hien loan bd 35 serotype S. suis, kc ca hai serotype 32 va 34 Vdi mue dich nghien ciru nhu vay, phuong phap nay khdng nham myc dich xac dinh chinh xac tung serotype ciia chimg S suis gay benh.
Trong nghien ciru nay. ngudng phat hien cua phuang phap I6S rDNA ddt vdi DNA tach tir mau da dugc chiing Idi khao sat va so sanh ddi vdi DNA lich tit dich nudi ciyvi khuin, DNA vi khuan duac
tach tir mau de gia lap su hien dien cua cac thanh phan irc che phan iing PCR cd ngudn gdc tir mau nhu hemoglobin, lactofernn, immunoglobin G. \ a heme (Al-Soud ^ / f l / . 2001. Akane ^/a/., 1994, Al- Soud el al, 2000) Ket qua cho thay vdi do tin ca\
95%, nguong phat hien cua phuang phap vdi DNA vi khuan tach tir mau (25 ban sao/phan img) cao hon nguong phan img vdi DN.A tirdich nudi cay (15ban sao/phan img) (Bang I) Su khac biet ve nguong phat hien nay cd the duoc giai thich la do phan img PCR khuech dai DNA trong mau mau van cdn bi uc che mdt phan do su hien dien cua cac thanh phan irc che neu tren
Phuang phap khuech dai I6S rDNA cua 5. suis da duoc ung dung trong nghien ciru xac dinh ty le ddng nhiem cua S. suis tren dan heo benh do virus gay hdi chiing rdi loan sinh san va hd hap tai mdt sd Tinh vao nam 2010 Mgt sd nghien cim trem md hinh heo trong phdng thi nghiem trudc day cho Ihay heo nhiem virus gay benh PRRS se cd bieu hien benh nang va tu vong caoneu bdi nhiem \di S. suis (Thanawongnuwech e/ al, 2000: Xu el al. 2010).
Do vay tinh hinh ddng nhiem vdi S. suis tren heo benh PRRS dugc xac dmh trong nghien cihi nay (10,6%) cd the giai thich cho tinh trang nghiem irong cua dich PRRS o Viet Nam irong nam 2010. Ngoai ra, su ddng nhiem cua S suis vdi 'urus gay hdi chirng rdi loan sinh san va hd hap ddng thdi cung cd the lam tang nguy ca nhiem benh cho ngudi trong thdi gian cd dich neu chung 5 suis ihugc serotype 2 va cd ddc linh cao. Do vay cac bien phap an loan lao ddng nham giam thieu nguy ca nhiem benh cho ngudi can duac chii trong ddi vdi cac ddi tugng la ngudi chan nudi, dieu tn va tham gia chdng dich KET L U A N
Vdi nhieu uu diem nhu dd dac hieu cao.ngudng phat hien luong ddi thap, de Ucn hanh, phuang phap PCR 16S rDNA cd nhi^u tnen vong ung dung trong viec phat hien S suis trong dich te ihii > nham danh gia tinh hinh mang tning hay nhicm benh cua heo vdi S SUIS, Phuong phap nay ciing cd ihc img dung trong chan doan benh nhiem S suis iren ngudi. nhal la trong cac trudng hap thai bai irong phan lap VI sinh.
Ldi cam on Chimg loi xin chdn tlianh cam an Sir Khoa hoc vii Cdng nghe Thanh iihii Ho Chi Xhnh (226 llD-SKttC\l to chin Wclhomc Trust I'mrng Quoc .-inh va I FDD Td ilun ( emrc foi Tropic cd Medicine Dim \i ngluen cini lam sang Dai hoc
Lam Tuan Thanh & Ngd Thj Hoa
Oxford da Idi Irg kinh phi cho nghien cini nay Xin cdm an gido su Marcello Gottschalk dd cung cdp DNA cua S suis ihuoc cdc serotype khdc nhau.
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Tgp chi Cong nghi Smh hgc\\({):\ 53-159, 2013
A M P L I F I C A T I O N O F T H E 16S r D N A FOR S P E C I F I C D E T E C T I O N O F STREPTOCOCCUS SUIS IN B L O O D S P E C I M E N S
Lam Tuan Thanh, Ngo Thi Hoa'
Cenire for Tropical Medicine, Oxford University Clinical Research Unit, Hospital for Tiopical Diseases Ho Cht Mmh City
SL M.MARY
Slreplococeus suis is a common opportunistic pathogen in pigs 5. suis is known as emerging zoonotic pathogen Human infection with S suis has been increasingly reponed in the recent years, specially in Asia Diagnosis for S suis infecUon is currently carried out with bacteria! culture or amplification of Ihe specific DNA, cps2Jgsne, for serotype 2 from clinical specimens Amplification for a specific region of 16S rDNA of S SUIS to identify S suis of all 35 serotypes in blood specimen was investigated to determine its limit of detection and specificity for diagnosis purpose.Blood samples of 521 porcine reproductive and respiratory syndrome (PRRS) virus infected pigs were investigated for co-mfection of S suis The high specificity with a limit of detection of 25 copies/reaction with DNA extracted from blood specimens were determined and 10 6%
of PRRS sick pigs were idenUfied to be co-infected with S suis The study results showed thai the specific S suis !6S rDNA methods can be used for diagnosis of 5 suis infection in humans and pigs
Keywords: I6S rDNA, blue ear diseases, coinfeciion. limu of clcieciion. PCR. porcine reprochictise and respiraloiy syndrome. Streptococcus suis
' Author for correspondence E-mail lioaniHunicru oig
