KHOA HQC KY T H U A T THU Y TAP XIX S6 3 - 2012
TINH HINH NHIEM VA MUfC DQ KHANG THUtfC CUA SALMONELLA SPP.
PHAN l i p Tir V|T VA MOI TRl/fiiNG NUOl TAI THANH PHO CAN THCf
Nguyin Dire Hiin' vd Phfim Thi Nhir Thdo'
T6MTAT
De xdc dinh tinh hmh nhilm vi miirc di khdng thuic cda Salmonella spp. hfn vit nuii tfp tiamg t^i Can Tho, mgt khdo sit duge tiln hinh hfn 389 miu ruit, phin nln chuing, nude ao nudi vd tiidre dn vit tiiu thip hi 270 h ^ chdn nudi vit quy md ldn. Kit qud cho tiily ti If nhilm Salmonella spp. chung cho vjt d vung khdo sit la 27,0% vi tii mii trudng nuii vit li 9,2%, hong dd serovar Enteritidis chilm ty If 5,9% vd Typhimurium Id 19,1%. Cic phdn Ifp Salmonella dd khing vdi phin ldn cdc lo?ii khdng sinh dang luu hdnh, ngo^i trir marbofloxaeine, oxytehaeyeline, fosfomyeine, amikacine vd hin hgp doxycycline + neomycine.
Tir khoa: Vit, Salmonella spp., Ty if nhilm, Khdng khing sinh, TP. Cin Tho.
Infected situation and antibiotic resistance of Salmonella spp. isolated from large scale duck farms in Can Tho city
Nguyen Due Hien and Pham Thi Nhu Thao
SUMMARY
In order to evaluate infected situation and antibiotic resistance of Salmonella spp. isolated from large scale duck farms In Can Tho dty, Vietnam, an investigation was carried out on 389 samples from intestine, faeces, feed and duckpond water collected from 270 duck farms in the outskirts of the city.
Results indicated that overall infected rate of Salmonella spp. in duck was 27.0% and in environmental materials was 9.2%, of which infected rate of serovar Enteritidis and Typhimurium was 5.95% and 19,05% respectively. Salmonella isolates in this study were resistant to almost populariy used antibiotics, except mariaofloxacine, oxytetracycline, fosfomyeine, amikacine and mixture of doxycycline + neomycine.
Key words: Duck, Salmonella spp.. Prevalence, Antibiotic resistance, Can Tho city
LDATVAND^
Salmonella dugc tim thiy hong phin, dIt, nude, xdc vit chet do bfnh vd la vi khuln duge quan tam nghien curu nhilu hen thi gidi vi nhdng tac ding ciia chdng doi vdi siic khde eon ngudi vd vit nudi. Trong dd Salmonella Enteritidis vd Salmonella Typhimurium Id hai serovar dugc nghien cdru khi nhilu vi chiing Id nguyen nhin
' Chi cyc did y TP.Cin Tha.
^ Khoa nong nghifp vd SHUD, D?u hpc Cin Tha.
gay bfnh d mft si lodi vit nudi hong dd cd vit, gay ngi dfc thgc phim vd cimg giy bfnh eho eon ngudi (Arestrup et al., 2003). Vift Nam Id mit nude ehdn nudi nhieu vit, nhung mdi ed mft vdi edng b i vl tinh hinh nhilm Salmonella hfn vit (Nguyin Thj Nggc Lifn, 1997; Trln Xudn Hgnh, 1998; Tran Thi Phan et al., 2005 vd Nguyin Thi Chinh vi ctv, 2010). Hon nOra, ehua ed mgt nghien ciiu ehi tilt nao vl sg hifn difn cda hai serovar ndy hen ddn vjt nudi tip trung cimg nhu mdi trudng chdn nudi vit, nhit la t^
khu vvrc xung quanh thanh phi Cin Tho. Nghifn
KHOA HQC K? T H U A T THO Y T A ? XIX S6 3 - 2012 curu niy nhim xic dinh nhdng vln dl trfn vi
ding thdi khio sit mOre di khing tiiuic cda vi khuln niy dl xic djnh lofii khing sinh hthi hifu sdr dyng trong dilu tri bfnh do Salmonella giy ra d cic ddn vit.
IL \^T Up] vA PHUONG PHAP NGHlfeN CtfU 2.1. V|t lifu
270 miu chit chura ruft, 90 miu thdrc in, nudc ao, phin nln chuing thu thip tir nhffng trgi vit nuii tip trung tgi cic huyfn Cd Dd, Phong Diln vi quin 6 Min nim d ngogi i thdnh phi Cin Tho. Chit chira ruit lly tir miu manh trdng, nudc ao nuii lly khoing 500ml ngay gin bd chuing vit, 50g thurc in tir ming vi khoing 50g phin trfn nln chuing. Tit ci miu diu duge cho vio chai hoic tui nylon vi trdng dl trong thdng Ignh vi chuyin ngay vl phdng thf nghifm.
Cic logi mdi tnrdng nuii cly vi giim dinh Salmonella spp. bao gim: BPW, Rappaport- Vassiliadis agar, BGA, KIA, LDC...
- Bi khing huylt thanh Salmonella polyvalent O, Salmonella monovalent 04,5; O9 vi O12 vi monovalent Hj, Hi^ vi Hg,„(Biorad Laboratories, USA).
2.2. Phutrng phip nghien curu
Nudi cly, phin lip vi giim dinh Salmonella tiieo TCVN 4829:2005
4829:2005/SD 1:2008.
vi TCVN Giim dinh Salmonella spp. dga vio cic phin umg sinh hda vi phin iing ngung kit vdi khdng huylt tiianh Salmonella polyvalent O.
Xdc dinh serovar Sal. Typhimurium vi Sal.
Enteritidis bing cic phin iing ngung kit vdi khdng huylt tiianh Salmonella monovalent 04,5;
O9 vd O12 vi khing huylt thanh monovalent Hi, Hi^ vd Hg.m(Biorad Laboratories, USA).
Khdng sinh di dugc tiigc hifn hfn 30 phin lgp Salmonella vdi 12 logi khing sinh sdr dgng pho bien hifn nay theo phuong phip Kirby-Bauer
vi dinh gii theo tifu chuln ciia Dgi hgc Y dugic TP. HCM.
m. Kh QuA NGHifcN ctru vA
THAO L U ^ 3.1. Ti If nhilm Salmonella spp. if miu mft v{tTi If nhilm Salmonella d miu ruit vit thu tiiip tii 270 hgi chin nuii vit tgi 3 huyfn Ph^g Hifp, Cd Dd vi 6 Mdn, Tp Cin Tho dugc trinh biy hong bing 1. Kit qui cho thiy ty If vit nudi nhilm Salmonella spp. khi cao, chilm tdi 27,0%.
Trong dd, ty If nhilm vi khuln niy d nh&ng vjt cd cic hifu chdrng sit, bd in vi tifu chdy (58,7%) eao hon hln d vit cd ding vf bl ngodi binh tiiudng (3,8%). Kit qui niy chimg td s^
hifn difn cda Salmonella spp. d ruit ddng vai tr6 quan trgng dii vdi tinh trgng sdrc khde cda ddn vit, cd thi bao hdm ci tic nhin giy bfnh nguyfn phit iin bii nhilm hoic kl nhilm.
Bing 1. Ty If nhiim Salmonella spp. d^ vit
Vjt bfnh Vjt binh thudng
Chung
s i miu XN 114 156 270
s i miu (•) 67 6 73
Tylf (%) 58.7 3.8 27.0
Vai trd cda mit si serovar Salmonella dii v6i siic khde cic din vit dugc xic nhin bdi nhilu nghifn cdru tiirdc diy d trong vi ngoii nudc. H If nhilm Salmonella khio sit tifn cic ddn vit d tinh Hi Tiy (hudc diy) li 21% (Nguyin Thi Ngpc Lifn, 1997), d cic tinh BIC Nmh vi Bic Giang li 19,02% (Nguyin Thi Chinh vi ctv, 2010), nhung d khu vvrc lin cin tiiinh phi Hi Chf Minh Igi len Kn 28,3% (Trln Xuin Hgnh, 1998). Si lifu chung cda chdng tii gin giing vdi kit qui khio sdt cda Trin Xuin Hgnh vi ctv, nhung eao hon nhilu so vdi si lifu cda Nguyin Thi Nggc Lifn vi Nguyin Thi Chinh vi ctv. Cd nhilu nguyfn nhin din tdi sg khic bift niy. Ngoii phuong thurc chin nuii vjt vi dilu kifn dia ly - khf hiu khic nhau, logi miu khio sit vi cich lly miu ciing nhu quy trinh nudi cly ip dvmg cd inh hudng ldn tdi kit qui thu
KHOA HQC K V T H U A T THU Y TAP XIX S6 3 - 2012 duge. Tuy viy, tit ci nhdng tic gii hfn diu khlng
dinh vai hd quan hgng cda nhilm Salmonella dii vdi tinh ti-gng sdrc khde ddn vit. Dilu niy cdng till hifn rd hong kit qui khio sdt cda chdng tdi cho thay ty If hifn difn cda Salmonella trong cic miu ruit lly tir vit ed bilu hifn bfnh ifn tdi 58,7%, hong khi dd d miu ruit lly tir vit cd ding vf bhih tiiudng chi d mure 3,8%.
3.2. Mure df i nhilm Salmonella spp. d mii trirdng nuii vit
s i lifu d bing 2 trinh biy cdc kit qui kilm ha xic djnh miic di d nhilm Salmonella d mii trudng nudi vit tir 3 nguin miu khde nhau duge thu thip i 90 hgi ehdn nudi vit tgi cic huyfn Phgng Hifp, Cd Dd vd 6 Mdn.
Bing 2. Ti If nhiim Salmonella spp. 6 mdi tnrdng nudi v|t
Logi miu
Nudc ao nudi Thd^in
Phin nin chuing Ting Chit chu'a mft
H. Phong Oiin S i
mSu 10 10 12 32 90
S i miu
(+) 1 1 1 3 23
Tllf nhiim
(%) 10,0 10.0 8.3 9.4 25,5
H.CdOi Si
mSu 13 12 14 39 90
S i mfiu
(+) 1 0 2 3 21
Tllf nhiim
{%) 7.7 0 14.3
8.1 23,3
Q. 0 Mdn S i
miu 16 15 17 48 90
SimSu (+)
2 1 2 5 29
Tllf nhiim
(%) 12.5
6,7 11,8 10,4 33,2
Tylf nhiim
trung binh
(%) 10.3
5.4 11.6
9.2 27,0
So lifu d bing 2 cho tiily mdrc d i i nhilm Salmonella d mdi trudng nudi vit tgi Cin Tho khi eao (9,2%). Trong dd, ty If phit hifn Salmonella trong miu thiic in (5,4%) thlp hon trong nudc ao nudi (10,3%) vi phin nln chuing nudi vit (11,6%). Cic miu thiirc in vi nudc ao nudi lly tgi huyfn Cd Dd cd khuynh hudng nhilm thlp hon (0 vi 7,7%), nguge Igi hong phan nen chuing Igi cao hon (14,3%) hai huyfn khac. Nhin chung, mire d i d nhilm Salmonella d mdi trudng nudi vit tgi 3 huyfn khio sit khdng khac nhau nhilu, nhung d huyfn Cd Dd, mft dia phuong cd truyin thing chin nudi vit vdi quy mi ldn, do thgc hifn tit cic bifn phip gom phin vi vf sinh nln chuing nfn cd miic di nhilm d nudc ao nudi va thdre in thap hon.
Cac nghien cdru trudc diy d nudc ta khio sat ty If nhilm Salmonella ehd ylu d phd tgng vit bfnh vi tning vit (Trln Xuin Hgnh vi ctv, 1999; Nguyin Thi Chinh vi ctv, 2010), cd rit ft
cic si lifu vl sg hifn difn cua Salmonella trong mii trudng ehdn nudi vit. Kit qud nghifn cdru ciia chiing tdi dd cung d p nhdng thdng tin hOii fch vl mire d i viy nhiem trong mdi trudng chdn nuii vd mii tuong quan giOra mure dg nhilm Salmonella d vit vi mure dg d nhilm mdi trudng. Kit qui nghien cdru ndy nhic nhd ngudi chdn nudi vit cin quan tim hon nifa vife thgc hifn cic bifn phip vf sinh thu y trong chin nudi vit dl giim thilu sg hifn difn Salmonella trong mdi trudng.
3.3. Ket qui xic dinh sg hifn difn hai serovar Salmonella Enteritidis vi SaL Typhimurium
Tir 84 phin lip Salmonella thu dugc hong hai Idiio sit trfn, Salmonella Enteritidis vi Sal.
Typhimurium di duge xic dinh bing phdn irng ngung kit vdi khing huylt thanh monovalent O vi H die hifu cho hai serovar nay. Kit qui nghifn ciiu duge thi hifn d bdng 3.
KHOA HQC K t T H U A T THU Y TAP XIX S6 3 - 2012
Bing 3. Ti If nhiim Salmonella theo loii Logi mfiu
Nudc ao nudi Thd'C i n
Phin nin chuing Ruft vjt bfnh Ruft vjt khde Ting
s i mfiu Salmonella
4 2 5 67
6 84
Salmonella Enteritidis
0 0 1 4 0 5
Tllf (%) 0 0 20 5.9 0 5,9
Salmonella Typhimurium
1 1 2 10
1 15
Tllf (%) 25 50 40 14.9 16,6 17.8
s i lifu d bing 3 eho tiily ti If phit hifn Sal.
Typhimurium (17,8%) tir cic ti-gi vjt nuii tip trung d Cin Tho eao hon Sal. Enteritidis (5,8%) tdi 3 lln. Sg hifn difn serovar Typhimurium edng phi biln hon, ed mit hong tit ci cic logi miu khio sit, hong khi Sal. Enteritidis chf dugc phdt hifn d miu ruft lly tir vit dang cd bilu hifn bfnh vd phin trgn nln chuing nuii.
NhOng nghifn ciru tnrdc diy eho thiy sg hifn difn cda Sal. Typhimurium hfn vit khi phi biln (Tsai & Hsiang, 2005; Tran Thi Phan et ai., 2005). Ket qui nghifn cdru gin diy nhit vl Salmonella d vit (Nguyin Thi Chinh vi ctv, 2010) cung cho kit qui tuong tg, dd li sg hifn difn cda Sal. Typhimurium (22,8%) d vit bfnh vi trumg vit tgi hai tinh Bic Ninh vi Bic Giang cao gip gan 3 lan Sal. Enteritidis (8,5%), ehumg td serovar nay nhilm phi biln hfn vit.
Hai serovar Enteritidis vi Typhimurium dugc eho li cin nguyfn giy bfnh phd tiiuomg hin ti-fn vit (duck paratyphoid) vi cd thi li nguyfn nhdn giy ngi die thgc phim d ngudi tifu thy trdrng vi thit vjt mic bfnh, do viy cin cd bifn phip gidm sit chit chS sg hifn difn cda chdng tgi cic trgi chdn nuii vit tip trung.
3.4. Mdrc di min cim cua Salmonella vdi die logi khing sinh thirdng sir dyng
Kit qui kilm ha mure di min cim cda 30 phin lip Salmonella, hong dd cd 10 phin 1^
thuic serovar Typhimurium vi 5 phin Ifp Enteritidis, dii vdi 12 logi khing sinh sur dyng phi biln hong khu vvrc dugc trinh bay d bing 4.
Bing 4. Mire
Tdn khing sinh (KS) Tilmicosin Enrofloxacin Flumequine Doxycycline Neomycine Florphenicol Gentamycine Ceftiofur Marbofloxaeine Oxytetracycline Fosfomyeine Amikacine
d i min cim
Ning dd KS
15 pg 5 MO 30 pg 30 pg 30IU 130 pg
10 pg 30 pg 5 MO 30 pg 50 pg 30 pg
cua cic phin lip Salmonella dii v6i mit s i idling sinh
s i mfiu kiim tra
30 30 30 30 30 30 30 30 30 30 30 30
Muc dd mfin cim cua Salnwnella Cao
S i mfiu 0 1 1 0 0 0 8 3 26 12 26 30
Tl If (%) 0 3.3 3.3 0 0 0 26.7
10 86,7
40 86,7
100
Trung binh s i mfiu
0 4 7 12 13 16 8 16
2 16
4 0
Tl If (%) 0 13.3 23.3 40 43,3 53,3 26,7 53.3 6.7 53,3 13.3 0
K S i mfiu
30 25 22 18 17 14 14 12 2 2 0 0
hdng Tllf(%)
100 83.3 73.3 60 56.7 46.7 46,7 40 6.7 6.7 0 0
KHOA HQC KY T H U A T THU Y T A P XIX SO 3 - 2012 Ket qui eho tiily cdc phin 1^ Salmonella dd
khang vdi phin ldn cdc khdng sinh tiidng dgng tgi Cin Tho, nhit Id tilmicosin, enrofloxacin vi fliunequme. Cdc khdng sinh cd hifu Igc hong dilu tri bfnh do Salmonella gay ra d vit ehi cdn 4 logi la marbofloxaeine, oxytetracycline, fosfomyeine vd amikacine. Kit qud khio sit cda ehiing tdi ciing tuong dong vdi nhdng nhfn xft eiia tie gii trudc ddy (Trln Xuin Hgnh vd ctv, 1999 vi Nguyin Thi Chinh vd ctv, 2010) vl miirc di dl khing cao cda
cdc phdn lip Salmonella dii vdi mft si logi khdng sinh thdng dgng.
Dk chgn edng thiirc phii hgp khdng sinh hOru hifu hong dilu tri bfnh do Salmonella tren vjt tur nhdng khdng sinh cd bilu hifn bj vi khuln khdng thuic, mft khdo sdt vl mure df min cdm vd tfnh da khdng eua cdc phin lip Salmonella dii vdi mgt si hSn hgp khdng sinh dugc tiln hdnh vd kit qud duge trinh bdy hong bdng 5.
Bing 5. Mi>c dd da khing cua cic phin ifp Salmonella dii vdi m^ts6 h6n hgp khdng sinh
S i loai khdng sinh
2 2 2 3 3 4 4 5 5 6
Hin hgp khing sinh
Til + Enr Enr + Flu Dox + Neo Dox + Enr + Til Dox + Neo + Til Dox + Neo + Til + Flo Dox + Neo + Til + Gen Dox + Neo + Til + Gen + Flo Dox + Neo + Til + Flo + Gef
Dox + Neo + Til + Flo + Gef + Sam*
Salmonella spp.
S i mfiu khing/30 mfiu 11
7 1 3 3 2 3 2 1 1
TI If (%) 36.7 23.3 3.3
10 10 6.7 10 6,7 3.3 3.3
* Sam: Ampicillin + Sulbactam
s i lifu t|q3 hgp d bing 5 cho mit kit qui rit dang quan tim hong vifc phii hgp khdng sinh dl dilu tri phi thuong hdn eho vjt. Trong cic hon hgp 2 khing sinh dugc tiiur nghifm, chi cd hin hgp doxycycline + neomycine Id cd hifu Igc doi vdi cdc phdn lgp Salmonella ihix nghifm vd cd till umg dyng hong dilu tii (3,3% phin lgp khing tiiuic). Sdr dyng hin hgp niy Idm nen vi phii hgp tiiem cdc khdng sinh khae lln lugt vdi 3, 4, 5 va 6 khdng smh, chung tdi nhin thiy vife phii hgp tiifm cic khing sinh khic khdng ldm tdng hifu qui dieu hi \d ti If cda so miu vi khuln Salmonella khang tiiuic khdng giim.
Kit qui khdo sdt vl mdrc di khdng tiiuic cda eac phan Igp Salmonella d hfn cdnh bdo cic tiid
y vien vd nhdng ehd hgi ehdn nudi vjt cin thgn hgng hong vifc chgn Iga khdng sinh dl dilu hi phd thuong hdn eho vjt. Dong thdi ed the khuyin cdo li hong dilu kifn hifn tgi, vife dieu tri nhilm khuln Salmonella hfn vit d Cin Tho chi nen sii dvmg cic khdng sinh sau: marbofloxaeine, oxytetracycline, fosfomyeine vi amikacine hay hSn hgp doxycycline + neomycine.
I V . l d T L U ^
Ti If nhiem Salmonella spp. chung d miu raft vit li 27,0%, hong dd d mau tii vjt bfnh la 58,7% vd tii vit ed ddng vf binh tiiudng chi 3,8%.
Nhu viy ed the cho ring Salmonella cd vai hd
KHOA HQC K t T H U A T THU Y T A P XIX S 6 3 - 2012
quan hgng dii vdi tinh hgng siirc khde cda cic 3.
din vit nuii tip hung vdi quy m i ldn.
- Sg hifn difn serovar Typhimurium phi biln hom Enteritidis d cic din vit v i mii trudng nuii
vit tgi Cin Tho. . Cic phin lip Salmonella tir vit v i mii
trudng nuii vjt tgi Cin Tho dl khing vdfi rit nhilu logi khing sinh khio sit, ngogi trir
marbofloxaeine, oxytehaeyeluie, fosfomyeine, 5.
amikacine vi bin hgp doxycycline + neomycine.
TAIU$UTHAMKHAO
1. Arestnip,F.M., M.Lertworapreecha, M.C.Evans,
A.BangtrakulnoUi, T.Chalermchaikit, H.C.Wegener (2003). Antimicrobial susceptibility
and occurance of resistance gene among Salmonella enterica serovar Weltereden from
different countries. J.Antimicro.Chemotherapy 52, 7.
pp. 715-718.
2. Trln Xudn Hgnh (1998). Kit qud budc diu nghien cihi tinh hinh nhilm Salmonella tren vit d Uidnh phi Hi Chf Minh vd mft s i tinh phy cfn.
Tap chi KHKT thii y,t^ VI, s6 I, n. 61-67. »•
Nguyin Thi Chinh, Nguyin Quang TInh vd Trin Thj Hgnh (2010). Nghidn cdru mft s i dfc tinh cOa S.Typhimurium v i S.Enteritidis trdn ddn vit t^i BIC Ninh, BIC Giang. T<fp chl KHKT thd y. t|p XVII, s i 4, tr. 28-33.
Nguyin Thi Ngpc L i ^ (1997). NghiSn cihi mft s i die dilm dich tl hpc bfnh phd thuang hdn vjt d Hd Tiy v i phdng tri- Luin vdn tiigc sy KHNN, Dgi hpc Ndng nghifp Hd Nfi.
Tran Thi Phan, Ly Thi Lien Khai, Natsue Ogasawara, Nguyen Thu Tam, Masato Akiba, and Hideki Hayashidani (2005). "Prevalence of Salmonella in pig, chickens and ducks in Mekong Delta, Vietnam". Joumal of Food Protection, Vol. 65 (5).
Thomason.M.B, Cherry B.W and David J.D (1977). Salmonella in health foods. Applied and Environmental Microbiology, pp. 602-603.
Tsai H.J and P.H Hsaing. (2005). The prevalence and antimicrobial susceptibilities of Salmonella and Campylobacter in ducks in Taiwan. Graduate histitute of Veterinary Medicine, National Taiwan University. Taipei, Taiwan.
Phgm Hdng Vdn (2002). Cim nang cdc ky thu|t vi sinh lim sing. Dgi hgc Y dugc TP. HCM.
THitU VACXIN, DfCN
COMGIA
C A MUAN
R O N GTheo Cyc diu y (Bf NN & PTNT), virus H5N1 dfi xult hifn nhdnh mdi 2.3.2 tiiay till cho nhdnh 2.3.4. Ri^ng nhdnh virut cQ (nhdnh 1) vin liTu hdnh 6 cic tinh phfa Nam. Nhdnh virut mdi da biln dii, chia tiidnh hai nhdnh phy A vd B cd sg khde bift ldn vl khdng nguytn. Trong dd, nhdnh phy A luu hinh d 23 dnh, nhdnh phy B luu hinh d 7 dnh.
Trudc tinh thi tr6n, Bf NN & PTNT da tgm dCmg tiCm phdng vacxin trong n&m 2012 dii vdi cdc dnh miln Bic, duyfin hdi miln Trung vd Tiy Nguyfin (vl vacxin cQ khdng cdn hifu lyc), ding nghia vdi vifc cic tinh tr£n dang phdi dii mdt vdi nhilu nguy cd bdng phit djch bfnh rit cao. Ong Vin Ding K^' Trudng phdng djch tl (Cyc thii y) cdnh bio: "Hifn d Campuchia dS c6 8 trudng hgp nhilm cdm gia d m vd diu tii vong trong thdi gian ngin. Nhinh virut mdi ndy di ding logt cd m$t d nhilu nudc trfin thi gidi nhu Trung Quic, Bangladesh, Ai Cfp... Do dd, Vift Nam cQng phii hit siJc thfn trpng". Cyc thii y cdnh bio, djch ciim gia d m vd cic biln dii vl virut ludn ludn c6 thi xdy ra, nhit Id trong bii cinh vacxin kh6ng cd hifu lyc vdi nhinh virut mdi.
Theo Ddn Vi^t 16/4/2012