SI/ THAY DOI O GEN 9 (VP7) CUA CHUNG VIRUS ROTA PHAN LAP 6 VIET NAM, 1999-2009
Nguyen Van Trang, Le Thi Luan*, Tetsu Yamashiro**, Le Thj Kim Anh. Vu Thj Uieh Hau, Le Thj Hong Nhung. Dang Dire Anh
I ien Ve Sinh Dich Te Trung Uong, Hd noi
* Trung tam nghien c iru san xuat viic xin vd sinh pliant y te, Hd npi
** Phong thi nghiem Hint \ghi -1 ien I 'e Sinh Dich Te - Dai hpc Nagasaki.
TOM TAT
Chung G1P[8] la chung Virus rota luu hanh phd bien nhat tren the gidi trong nhieu thap ky nay Gia thuyet cho su ton tai ciia chung nay la kha nang bien doi chung nham tranh nhan biet bdi he miln dich Trong nghien cuu nay, chung tdi danh gia su thay ddi ciia chiing Virus rota G1 P[8] phan lap d tre em tai Ha Ndi, Hai Phong, Khanh Hoa va Thanh phd Ho Chi Minh trong thdi ky tir 1999-2009. Miu phan (n=55) thu thap tir tre mac tieu chay cap tai benh vien va xac dinh la chiing G1P[8] dupe sir dung de giai trinh tu gen 9, ma hoa protein VP7, mot protein thudc Idp capsid ngoai ciia Virus rota. Nghien ciru ciia chiing tdi cho thay d 3 dja diem Ha Npi, Khanh Hca va thanh phd Ho Chi Minh, gen 9 (VP7) ciia chiing G1P[8] da thay doi tir G1 cluster III trong nhung nam 1999 va 2003 sang cluster I trong nam 2007 va 2009. Su khac biet ve nucleotide giCra 2 cluster nay la 6-9%. Mot sd khac biet ve trinh tu axit amin giua 2 cluster cung da dupe tim thay, trong dd cd nhung thay ddi tai viing quyet dinh khang nguyen A va C, cho thay kha nang thay ddi tinh khang nguyen giua 2 cluster tren Cac chiing virus phan lap d Hai Phong cho den 2007, khdng theo xu hudng tien hoa chung nhu d 3 dia diem tren, ma van thupc G1 cluster III. Hon the nCra chiing Virus rota phan lap d Hai Phong cung cd nhung dac diem gidng vdi chung phan lap tai Trung Qudc va dupe xep vao ciing nhdm vdi cac chiing phan lap d day, cho thay tinh da dang chiing a Hai Phong cd the bi anh hudng bdi su da dang chiing d Trung Qudc.
Tir khoa: Virus rota, G1P[8], Gen9, VP 7, Viem da day rudt cap I. DAT VAN l)L
Virus Rota la tac nhan quan trong nhat gay \ ic'iu da day rudt cap d Ire em. 6 nude ta
>50% tre nhap \ ien vi tieu chay do Virus rota [ l |. Virus rota, thudc hp Reoviridac la virus khong vo. cd vat lieu di truyen la ARN kep, phan bd thanh I l doan gen (thii tu tir I-I l), trong do doan gen 4 va gen 9 ma hoa tuong irng cho 2 protein YP4 va VP7 thupc Idp capsid ngoai ciia virus [2]. Virus dupe phan
loai thanh genoty pe/serotypc dua vao 2 pro- tein niiy. va dupe ky hieu tuong ling la P va G. Chung Virus rota luu hanh phd bien nhat tren the gidi la G l P[8|. va day la ly do GSK, Bi phat trien vac xin don gia Rotarix dua tren chiing virus nay . Vac xin nay dupe dua vao sir dung d mpt sd nude tren the gidi tir nam 2006.
Ddng thdi d nude ta. trung tam nghien ciru san xuat vac xin vii sinh pham y te (POLYVAC) cung dang san xuat \ ii dua vao thii nghiem vac xin phong Virus rota (Rotavin). don gia. dua Tac gia: Nguyen Van Trang
Vien Ve Sinh Djch Tc Trung Long, Sd I phd Yersin. Ha Npi Tel: 844-39718491
I mail: nvtransi T( simail.com
60 Tap chi Y hpc du phong. Tap XX, so 6(1 141
tren chung Virus rota G1 P|8] phan lap d nude ta |3|. Dong thdi. vac xin Rotatcq (Merck) bao gdm 5 chung virus G 1. G2. G3. G4 va PI A[8]
cung dang duoc su dung d nhieu nude tren the gidi. Tuy nhien van de dang duoc quan tam la su bien ddi chung virus luu hanh cd anh huong den hieu luc cua vac xin khdng.
O nude ta, nhan biet tam quan trong cua virus nay. chuong trinh giam sat viem da day rudt cap o tre em dudi 5 tudi duoc.thuc hien tu nhung nam 1998 do Vien Ve Sinh Dich Te T\Y va van dang duoc tiep tuc bdi POLY VAC [1].
Vide giam sat duoc thuc hien o cac benh vien Idn dai dien cho lung viing Bac. Trung, Nam.
Ddng thdi o nude ta, cung cd nhieu nhdm nghien ciiu ric-ng biet khac ve Virus rota a Fla Ndi. Khanh Iloa va thanh phd lid Chi Minh.
Nhung chuong trinh giam sat virus trong thdi gian dai vii o cac dia diem khac nhau cho phep danh gia sir thay ddi cua cac cluing virus luu hanh dai dien ho loan qudc, su xuat hien cac chung mdi. nham giup danh gia vice sir dung viic xin.
trong nghien ciru niiy. chiing tdi theo ddi su thay ddi o gen 9, mil hda protein VP7 cua cluing G1P|8| d cac viing khac nhau ciia nude ta tir nam 1999 den nay. nham iheo ddi sir tien hoa ciia cluing virus nay trong 1 1 nam giiiln sin.
I. PHI ONG PII/VP NGHIEN ( 1 11 2.1 \ at lieu
Cluing idi sir dung mini phan thu thap tir tic dudi 5 tudi nhap vien do viem da day rudt cap. duong tinh voi Virus rota. Cite man phan nay duoc xac dinh la genotype G1P|8| bang phuong phap nested RT-PCR trudc khi thuc hien giai trinh tu gen 9. Cac man niiy duoc thu thap lai Benh Vien Nhi Trung Uong (13 man). Benh vien Nhi Dong I. thanh phd Hd Chi Minh (1 3 man). Benh \ ien Khanh Hoa (1 8 man) \ ii Benh \ ien Nhi Hai Phong (II mau) phan lap trong nhiing nam 1999-2009 trong
chuong trinh giam sat tieu chay do Virus rota (Bang 1).
2.2. Phuong phap
Tach chief ARN cua virus: Mau phan duac hoa trong nude cat thanh hon dich 20% va ARN cua virus duoc tach chiet sir dung Qiagen viral RNA mini kit (Qiagen, GmbH, Dire), theo hudng dan cua nha san xuat. ARN tach chict duoc, chia thanh cac tuyp nho va luu tru o -80"C.
Giai trinh tu gen 9: Doan gen 9 (896 bp) dupe khuyech dai bang cap mdi 9con I (2 AGCTCCTTTTAATGTATGGTAT ) va VP7R (AACTTGCCACCAT(T.C)T(T.C) TTCC) V l,j qUy trinh nhu sau: 2ul ARN dupe pha loang trong 8uI DI PC H 11 va bien linh tai 97°C trong 5 phiit, shock nhiet tai ()"C. va cho vao tuyp bao gdm 0.5uM mdi (mix). Ac- cess quick master mix vii AMV (lul) (Pro- mcga. Madison. Wl, Hoa ky). San pham PCR dupe tao ra trong dieu kien nhu sau: 45"C trong 30 phut; 95"C trong 5 phiit; 30 chu ki (94"C trong I phiit; 42"C trong 2 phut; 72"C trong 1 phiit): 72"C trong 7 phiit va giir o 4"C. Cac phan ung PCR deu cd chirng duong va chung am. San phiim PCR dupe tinh che bdi kit QlAquick Gel Lxlraclion kit (Qiagen GmbH. Hildcn. Dire) theo hudng dan cua nha san xuat. San pham PCR tinh che diroc dpc trinh tu sir dung kit giai trinh tu AB1 Prism"
Big Dye Terminator v3.1 trong dieu kien nhu sau: mdi 9conl hoac VP7R (0.25uM). san pham PCR (25-30ng), Big-dye va dem. Cac phan irng giai trinh tu gen deu dupe chay ciing chirng duong pGEM*-3/.T( i). Dieu kien phan irng nhu sau: 96°C trong 1 phut, 25 chu ky bao gdm 96°C trong 1 0 giiiy. 5()"C trong 5 giiiy
\ii 60°C trong 4 phiit. San pham giir tai 4"C.
Moi san pham PCR dupe dpc ca 2 chieu xudi
\a ngupc sir dung 2 moi tren. Kit Dye-ex 2.0 spin dupe sir dung tiep theo dc loai bd Big- dye con du lai trong phan irng. theo hudng din cua nha san xuat (Applied Biosystcm. Foster City. CA. Hoa Ky ). Qua trinh giai trinh tu thuc 'Tap chi Y hpc du phong. Tap XX. so 6 (1 14) 61
hien tren may Sequencer 3130 (Applied Biosystem.
Foster City. CA. USA) tai phong thi nghiem huu nghi NTHE-Nagasaki. Cac phan tich duoc thuc hien tren cac chuoi nucleotide (793bp). Du lieu chuoi gdc dau tien dupe phan tich bdi phan mem Bioedit va du lieu trinh tu xudi. nguoc cua mdi mau dupe sap xep bang each su dung phan mem Mega 4.1 de co dupe nhirng trinh tu cudi ciing. Sap xep hoan chinh (alignment) duoc thuc hien vdi Cluster W (Mega 4.1). Thuat toan Maximum Parsimony dupe sir dung de xay dung cay phat sinh loai vdi 1.000 lan lap lai.
III. KET QIA
3.1 Thay doi cluster chiing virus rota GI d' nude ta trong giai doan 1999 va 2009
Gay phat sinh chung loai dua vao trinh tu gen 9 (VP7) ciia cac chung RV G1 P| 8] phan lap trong giai doan 1999- 2009 tai Benh vien Nhi Ddng 1, thanh phd Eld Chi Minh (hinh la). Benh vien Nhi Trung Uong, Ha Ndi (hinh lb). Benh vien tinh Khanh Hoa (hinh
Ic) va Benh vien Nhi Hai Phong (hinh Id) so voi cac chiing tren the gidi. Chung DSI (G2P(4|) dupe sir dung lam chung ngoai nhdm (out-group). Cac chung phan lap trong nghien ciru niiv dupe ddng khung. Dia diem phan lap duoc v ii't tat trong ten chung nhu sau: T1CMC, Benh vien Nhi Ddng 1 -thanh phd Hd Chi Minh: NTD. Benh vien Nhi Trung Uong-Ha Ndi; N T. Benh v ien tinh Khanh Hoa; HP. Benh v ien Nhi Hai Phong). Ten viet tat cac nude noi phan lap chiing: CN: "Trung Qudc. VN: Viet Nam. JP: Nhat Ban. US: I loa Ky. Brz: Brazil.
T\V: Dai loan. YNZ: Venezuela.
l ong cdng 55 chiing Virus rota G1P[8|
dupe giai trinh ty v a phan tich cay phan chimg loai o Benh vien Nhi Ddng 1, TP Hd Chi Minh (Hinh la). Benh vien Nhi Trung Uong (Hinh lb). Benh vien tinh Khanh Hoa (Hinh Ic) va Benh vien Nhi Hai Phong (Hinh Id). Kich thudc ciia doan gen cd trinh tu la 793bp. Cac chiing virus phan lap o Viet Nam dupe SP sanh
vdi cac chung phan lap o Viet Nam va tren the gidi da dupe dang ky tai Genbank. Trong sd 7 cluster thudc genotype GI, cac chung Viet Nam cluster I vii 111.
O Thanh phd lid Chi Minh tir nam 1999-2003, phan Idn trinh tu ciia gen 9 ciia cac cluing G1 P| 8 ] phan lap dupe thudc cluster 111. ciing vdi cluing viic xin phong Virus rota ciia Viet nam Rotavin (Hinh la). "Trong khi do cac chiing phan lap gan day (2009) da thudc ve cluster I. ciing vdi cluing vac xin Rotarix.
Su khac biet giira cac chimg thudc 2 cluster nay la 6.7-9%. tuong duong vdi sir khac biet giua cac cluster khac (cluster 11.1V. V) so vo i cluster 1 va III (so lieu khong trinh bay).
Tuong tu nhu o thanh phd Hd Chi Minh, cac chung G1 P|8] phan lap d Benh vien Nhi Trung Uong da thay ddi tir cluster III nam
1999 sang cluster I trong nam 2009 (Hinh lb).
C) Benh vien tinh Khanh 1 loa, cd the thay rang cac chiing RV da bien ddi sang cluster 1 sdm hon, trong nhung nam 2006-2007 vii cd the trudc nua (Hinh I c). Sit thay ddi G 1 cluster o' cac dia diem a Viet Nam cd the lorn tat trong Bang 1. Nhu vay cd the ket luan rang cd sir bien ddi tir cluster 1 sang cluster III ciia chimg RV (i I P| 8] trong khoang thdi gian la 10 nam va xay ra d nhieu dia diem trong toan qudc.
Khac vdi cac chimg d Ha Npi, thanh phd Hd Chi Minh va Khanh Hoa, cluing G1P|8|
phan lap d Hai Phong phan Idn van thudc clus- ter 111 trong nam 2007 (Hinh Id) va mpt chiing (HP802/2007) cd the thupc cluster I, cung vdi cac chirng phan lap tai Hpa Ky trong nam 2007.
Trong nam 1999. ca 2 cluster III va I cung ton tai song song d 1 lai Phong. Mpt dieu dang chu y la cluing tir Hai Phong thudc ciing nhdm vdi cac chung tir Trung Qudc nhu R833-CN-05.
CY5-CN-07. Chi83-C'N-05 v.v...
Khi so sanh trinh tit axit ainin cua cac chung phan lap a Viet Nam va cac chung chuan tren the gidi. cd the thay su khac nhau giua cluster 111 vii 1 o mpt sd vi tri axit amin 62 Tap chi Y hpc du phong, Tap XX. so 6 (1 14)
H i n h 1a
- Rotavli - VN-36S-VN-03 -CMHOtO-Qi-U-Ot - TlateOi-Tl-Oi -VIKiS-VhHB - VIK5I-VN-03 -VNi8l-VfW3 - V N-7 18-V N-03
HC IK 1 C-V N-99
HLHCISH-VM-W HCMCIW-V(M9
- HIO-HfcaHD-Oi - DlakalMU-eL-o*
- DlJkl.'.03-f l-c.3 - C M H&3S-0 i-Tl-Ol - TlaHiOi-Tlfl*
- p j 1.3-c u-cc - CH-8J-CM-C6 - R833-?H-03 :H'::8I-.
S-CN-O:
Ihl1 - PA7F;,SQ - PICKO - P r - CKIP-SO - I 5i-UO<y5 - AU0U7-JP-O2 - G IE6-.i IH<3 - J,,|OI :3u-M - DCIJ3-T.W4S - Cw^ 0-35 - Potirti - H : n rsi-VM-09 - H : M " • .• fK*
- H : M :;;>VN-W
- H : r.i :: i-v IK-S
- H : M ::&VIH»
- H a ITSO-VIKfi - H' a - H' M TO.l-VM-03 - t U-JP -05 - VV - E nn5-6 PZ-^K - 5 rz-6 - Por.-vz-y P7 r' - F'Oi'v'I-'I'-X"' - DC-I-4JO-07
/• (III)
J
} (V)
(II)
(I)
J
(IV) (VII) Tap chi Y hoc du phong. Tap XX, so 6(114) 63
H i n h l b . SYS- CN-07 . P333-CN-05 . Cii-84-CN-u5 - PJ13-CM-07
MTD36-WB9 ."llia.12C4-Tl.-04 .aiHD3C-D4-TW4 . Diak3303-BL03 - Tlia-SLUTUM . CVIHO<-D4-TL-04
NTD45-VN99 NTD38-VrT9.y . DC03-TIV-99 . JaparfiO-93 - G19CB-ALI-9S - Rjtarix
- CJS-70-95
NTDB81-VN-09 NTD354VN-09 NTD883VN-09 NTD875VN-D9 NTD87D-VN-09 NTD37&VT+09 NTD886VN-09 NTD869-VT+D9 NTD37&VN-09 -421-JP-93 - KS4-USSS - PW8/8E - P^'yO - PMD/9C - WD-JP-D5 - Wa-83 -
_ P3r/'./ZVP7Y - P:r/v2CS5>!
_ DS-1-US-07 i J f
(II) (V)
(IV) (VII)
(.4 Tap chi Y hoc dir phong, Tap XX. so .6(114)
H i n h 1c
Nuuo-vN-yy NT204-VUOO tTO03-VN-99 NT207-VN-9S NT199-VU99 . Roi3\fn -Tha SO-1TLD-1 . QMHD4)-04-TU)4 .Tha-1204-TL-D4 - rjhaka3-03-BL-u3 - UMHKJB-U4-IL4J4 . PJ13.CN.J7 - Ohi-8+CN-D5 - S Y5-CN-D7 - F833-CN-05 . uiaib-A)>yy - AUB07 JP 02 - Japan30-95 - DC03-TW-99 - Rotari>:
- Ccs-70-95 NT063O VN 07 NTD599-VN-D7 mu651-\7N-u7 NT196-VN-09 Niioa-VN-ua WT102-VN.O0 NTD4\vN-09 NT171-VN-D9 rra)5-VN4)9 NTI09-VN-O9 WT161 VNOO NT173-VN-D9 NT155-VN-Q9 -421-JP-93 . PAICUW - P.W8/S9 - P.M/90 . KIJ-JP-D5 - W3-y:j - Brr « BRZOf . BrzJ3 - Por.'vSVP7Y - Por>VZC95X - D4-I-US-D7 Tap chi Y hoc du phong. Tap XX. so 6 (114)
V (III)
J
\
\ (I)
(II) (V) (IV) (VI l j
65
H i n h I d
Hinh 1. Cay phan chung loai xay dung dya tren trinh tir gen 9 ciia Virus rota 66 Tap chi Y hoc du phong, Tap XX, so 6 ("1 14)
Bang 1. Sic thay doi G1 cluster trong vong 10 nam tai cac dja diem nghien ciru G1 cluster (nam phan lap) Dja diem phan lap
1998-1999 2003 2006-2007 2009 Benh vien Nhi Trung Uong - Ha Npi III Khong co mau Khong co miu I
Benh vien Nhi B6ng 1 - TP HCM III III" Khong co mlu I Benh vien tinh Khanh Hoa III Khong co mlu I I
Benh vien Nhi Hai Phong III Khong co mlu III,I Khong co mlu
Ghi chii: H: Irinh tir phun kip lai Benh vien Nhi ddng 1, ho i nhom tdc gia Ushijima yd cdng sir [4/
3.2 Sir thay doi trong trinh tir axit amin ciia cac chiing virus phan lap a Viet Nam thuoc cac < .l cluster khac nhau.
Bang 2. Nhirng thay d6i trinh tir axit amin giCra cluster III va I ciia chiing virus rota G1 va moi lien he vcVi khu vyc khang nguyen tren VP7
Vi tri axit amin tren protein VP7 G1 cluster III GI cluster I Khu vuc khang nguyen
29 lie Met
37 Phe Ser
67 Tyr Ala
68 Ser Ala
75 Vai lie
94 Asp Glu A
108 Thr lie
123 Asn Ser
217 Thr Met C
268 lie Vai
Tap chi Y hoc du phong. Tap XX. so 6 (I 14) 67
Cluster HI Cluster I
Wa-VPI Rotavin MTD36-VN-99 HP08-VH-99 NT199-VN-99 HCMC194-VH-99 Rotarix HTD810-VN-09 NT04-VH-09 HCMC750-VH-09
V TR It ID II . e
l.LITV L L1K
E E E J . E Cluster III
Cluster I Wa-VP1 Rotavin NTD36-VN-99 HP08-VN-99 NT199-VN-99 HCMC194-VH-99 Rotarix NTD870-VN-09 NT04-VN-09 HCMC750-VN-09
LIKv PT..5V KE u rv QTL:I c;TTtiVD" EH EIJEKL
|.... | .... | 270 JSltvlDIT DP'
I
Hinh 2. Trinh ty axit amin thay doi giu>a cluster III va I ciia chung rotavirus G1 duoc trinh bay trong hinh 2 va bang 2. Trong
so nhung thay doi nay. su thay doi o vi tri 94 va 217, tuong ting thuoc khu vuc khang nguyen A va (' co kha nang dan den thay doi tinh khang nguyen ciia YP7 trong khu vuc nay. Mot so chiing virus tii I lii Noi. I lai Phong va thanh pho 116 Chi Minh ciing co dot bien tir Thr sang Asn tai vi tri 91, giong nhu quan sat doi voi cat chung o Nhat Ban va liung Quoc.
IV BAN I I AN
Sir thay doi khang nguyen trong ciing mot scroty pe la phirong thirc dc virus lan tranh nhan hiel boi he mien dich. Mot quan sat 6' Y trong sum 19 nam. cho thay lien tuc co nhirng kieu da dang (variants) cua chiing Virus rota GI. do co the la ly do chiing virus nay ton tai trong mot thoi gian dai lien the giai [5 |. I lien tai co 7 G I cluster da duoc mien ta. Khi so sanh cac chiing phan lap o nude ta va cac cluing khac trong khu vuc nhu Thai Lan, Trung Quoc. An Do ciing cho th ax su luu hanh rong rai ciia 2 cluster GI \ii GUI. trong khi do ciic cluster Gil Va GIV cua cac chung phim lap tu nhirng nam
1970 nhu Wa. KI i da khong con luu hanh nira.
Nghien ciru ciia cluing toi trai qua I I nam ciing voi mot so trinh tu trong nunc tir mot nghien ciru khac con cho thay co sir thay doi ciia chiing GI tir cluster 111 trong nhiing nam 1999-2003 sang cluster I trong nhirng nam 2009 6' 3 khu vuc Ion. Ha Noi. thanh pho 116 Chi Minh va Khanh Hoa |4|. Su chuyen doi cluster niiy co the da xay ra sdm hon. trong nhirng niun 2006- 2007 nhu quan sat a Nha Trang. Khanh Hoa.
Nghien ciiu ciia chung toi ciing triing lap voi quan silt 6 I Ian Quoc. cho thay chiing GI phan lap trong nhung nam 2004-2006 da thuoc vao lineage I |6|.
Khong giong nhu quan sat o 3 dia diem tren. cac chung thuoc Hai Phong lai di theo xu huong tien hoa va da dang rieng. Tinh den nam 2006-2007. cac chung phan lap a Hai Phong thuoc ciing nhom voi cac chimg phan lap 6' Trung Quoc. \a hien dang thuoc cluster III. Do mau khong duoc thu thap trong nam 2009 o Hai Phong, chiing toi khong the quan sat cu the hon xu huong lien hoa cua chung GI 6 dia diem nay trong nam 2009. Giam 68 Tap chi Y hoe du phong. Tap XX. >6 6(1 14)
sat d Hai Phong cung nam (2007) cho thay su gia tang dang ke cua chiing virus G3. Van con chua ro rang ve xu huong luu hanh pho bien cua cluster I d Hai Phong co xay ra trong nam 2009 hay khong. Tuy nhien, co the thay ro chiing luu hanh a ilai Phong chili nhieu anh huong boi chiing luu hanh 6 Trung Quoc.
l uong tu. rat nhieu chiing virus a nude ta dac biet la trong nhung nam I 999 d Benh vien Nhi Trung Uong, trong nam 2007 0 Hai Phong va mot trudng hop o thanh phd Hd Chi Minh cd bien ddi d axit amin 91 ( Thr sang Asn). Trudc kia, tac gia "Trinh va cong su cho rang su bien ddi nay chi xay ra ddi vdi chung phan lap tu Nhat Ban va Trung Qudc |4|. Vdi vi tri dia ly giin Trung Qudc va sir giao luu qua du lich va thuong mai. cd the thay vice xam nhap ciia cac cluing virus d cac nude khac vao nude ta de dang xay ra.
Su thay ddi trong trinh tu gen cd y nghia quan trong khi thay ddi nay dan den thay ddi trong trinh tu axit amin. Ddi vdi VP7.
cd 4 viing khang nguyen la viing A (axit amin 87-101), viing B (axit am in 142-1 52). viing C (axit amin 208-221) va viing D (axit amin 291 )[7]. Sir thay ddi giua CI cluster III va I o cite chung phan lap d nude ta roi vao viing khang nguyen A vii C. cd kha nang dan den su (hay ddi ve tinh khang nguyen. Nghien ciru sail hon sir dung khang the don ddng nham vim khu vuc cd nhirng bien ddi nay se cho biet chinh xac ve sir thay ddi tinh khang nguyen n;i\. Mdi dieu thii vi nfra la cluing vac xin Ro- tarix cd gen 9 thudc v c cluster I. ciing G1 clus- ter voi cac cluing GI tren the gidi (ke ca Vict Nam). Cd the thay rang cluster I da xuat hien trong nhirng nam 1980 khi cluing vac xin niiy (89-12) duoc diing de giiy nhiem te bao va tao vile xin. sau do cac cluing virus chuyen sang cluster III vii hien nay quay lai cluster I.
Sir thay ddi tinh khang nguy en cua RV khdng chi dua vao trinh tu gen 9. mil cdn can phai theo ddi sir thay ddi ciia gen 4 (VP4). la
mot trong hai khang nguyen quan trong cua RV. Hon nua, su bien ddi nay can nhin tdng quan tren toan bp 1 I doan gen ciia virus de thay dupe su thay ddi chung. chir khdng chi dua vao 2 gen ma hoa khang nguyen thupc Idp capsid ngoai. Can cd nhirng nghien ciiu tiep theo vd su bien ddi nay. Nhirng nghien ciru nay ddng vai trd quan trong, nham danh gia vice su dung vac xin d nude ta ciing nhu cd can thiet thay ddi chung virus trong vac xin hay khdng.
V. KET LUAN
Trong giam sat ciia chiing tdi til1 1999- 2009. gen 9(VP7) ciia cluing Virus rota G1 P|81 phan lap d Ha npi, Khanh 1 Ida va Thanh phd Hd Chi Minh da thay ddi til' cluster GI sang G3. trong khi dd o Hai phong van ton tai song song cac chiing G1P|8| vdi gen 9 thudc ca 2 cluster tren. Chimg tdi quan sat thay cd sir thay ddi tren trinh tir axit amin d viing khang nguyen cua gen 9, cho thay kha nang cd bien ddi tinh khang nguyen giua 2 cluster nay. Do dd, can cd nhung nghien ciru trong nhieu nam ve su bien ddi nay nham danh gia viec sir dung vac xin cung nhu dc xem xet su thay ddi chiing trudc va sau khi sir dung vac xin.
Ldi aim irn: Chimg Idi chdn thanh cam an Tien sy () Nakagomi, Dai hoc Tdng hop Nagasaki, Nlidt han ve sir giiip du nhiet tinh vdi nhirng trao ddi khoa hoc i/uy hdu vd sinh pham giai trinh tir Chimg tdi cung xin ciun on Bdc sv Nguyen Thi Thirdng du hd tra sir dung muy giai trinh tir gen.
De tdi duoc sir hd tro' i t' kinh phi cua Id citiic )' Te the giai vu cuu Dai hoc Tdng hap Nagasaki TAI LIEU THAM KHAO
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Tap chi Y hpc du phong. Tap XX. so 6(114)
GENETIC VARIATIONS IN GENE 9 (VP7) OF ROTAVIRUS G1P[8] STRAINS ISOLATED IN VIETNAM, 1999-2009
Nguyen Van Trang, Le Thi Luan*, Tetsu Yamashiro**, Le Thi Kim Anh, Vu Thi Bich Hau, Le Thi Hong Nhung, Dang Due Anh
The National Institute of Hygiene anil Epidemiology, Hanoi;
* Center for Research and Production of Vaccines and Biologicals, Hanoi
** NIHE-Nugasaki Friendship Laboratory, Hanoi Rotavirus strain GlP[8] is the most
common strain infecting human around the world over the past few decades. The hypoth- esis for this popularity is the ability of this strain undergoes constant genetic/antigenic changes to avoid host immunity. In this study.
we assessed the change in the VP7 gene of dif- ferent rotavirus G I P[8J isolates, from children in Hanoi, Hai phong, Khanh Hoa and Hochim- inh city from 1999-2009. Rotavirus positive fecal samples (n-55) collected from children admitted to hospitals in these regions for gas- troenteritis and genotyped as G1P[8] were used for sequencing of the gene 9, encoding the VP7 capsid protein. In all 3 sites Hanoi, Khanh 1 loa and Hochiminh city, the gene 9 of G I rotavirus strains have evolved from cluster
111 in 1999 and 2003 to cluster I in 2007 and 2009. Strains in these two clusters have 6-9%
divergence in nucleotide sequences between one another. Several differences in amino acid sequences between the 2 clusters were identi- fied. 2 of which fall in antigenic region A and C. suggesting the possible difference in anti- genic properties. Unlike isolates from other 3 sites, isolates from Haiphong still belongs to cluster III, similar to the trend in China, Rotavirus isolates in Hai phong showed simi- larities with Chinese isolates and in the same group with those from China, suggesting the strain diversity in this city could be influenced by the trend occurred in China.
Key word: Rotavirus, Gene 9. VP7.
Acute gastroeuteritis
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