SO SANH KET QUA PHAT HIEN VI SINH VAT TRONG KHONG KHI GIUA PHUONG PHAP OAT DIA THACH VA SU" DUNG MAY HUT MAU KHONG KHI
Trjnh Quynh Mai, Nguyen Thanh Thuy. Tran Quang Binh. Phan Trong Lan*
Vien Ve sinh Dich te Trung uong,
* Bd Y te TOM TAT
Nghien ciru so sanh ket qua phat hien vi sinh vat trong khong khi giua phuong phap dat dTa thach va phuong phap sir dung may hut mlu khong khi dddc tien hanh tai 10 phong thi nghiem y sinh hoc cua Vien Ve sinh D|ch te Trung Udng nam 2007. Ket qua cho thay hai phddng phap deu phat hien so loai vi sinh vat nhu nhau trong khong khi nhung so lUdng vi khuan hieu khi co duoc bing phudng phap dat dTa thach cao hon so voi phddng phap sd dung may hut khong khi. Su chenh lech nay co anh hudng den viec phan loai mdc do 6 nhiem vi sinh vat theo cac tieu chuan khac nhau.
TU khoa: Vi sinh vat trong khong khi, do dp sach khong khi, khong khi phong xet nghiem I. DAT VAN DE
Mdi trudng khdng khi ciia phdng thi nghiem (PTN) y sinh hoc la mdt trong nhiing yeu td quan trong gdp phan dam bao dd chinh xac ciia cac xet nghiem va an toan sinh hoc (ATSH). Nguyen nhan gay ra d nhiem khdng khi phdng thi nghiem cd the do bui. khdi, dp am, nhiet dp va dac biet la cac vi sinh vat.
De danh gia mile dp d nhiem vi sinh vat (VSV) cua phdng thi nghiem, phddng phap thudng du'dc sii dung la phddng phap lang bui trite tiep tren dia thach ciia Koch [1]. (lan day. vide lay mau khdng khi bang may hut miiu khdng khi da dUdc ap dung. PhUdng phap nay cho phep xac dinh chinh xac sd lUdng VSV trong mot lUdng khdng khi nhat dinh.
Nghien ciiu tien hanh nham so sanh kha nang phat hien sd lUdng va chiing loai vi sinh vat trong khdng khi giiia phUdng phap dat dia thach va phddng phap sti dung may hut mau khdng khi, tii do cung cap cd so dii lieu de quyet dinh
chpn phUdng phap danh gui d nhidm vi smh vat phdng thi nghiem phu hdp.
II. PHUONG PHAP NGHIEN CUU 2.1 Doi tUcfng nghien ciru
Mdi trddng khdng khi trong 10 phdng thi nghiem y sinh hoc thuoc 5 khoa ciia Vien Ve sinh Dich te Trung Udng (VSDTTU): 1 PTN ciia Khoa virut, 6 PTN ciia Khoa Vi khua'n, 1 PTN thudc Khoa Mien dich va Sinh hoc Phan tii, 1 PTN Khoa Cdn trung va Ddng vat Y hoc va 1 PTN ciia khoa Dao tao va Quan ly Khoa hoc.
2.2 PhUouig phap nghien ciiu 2.2.1. Lay mdu khong khi
a) Lay mau bang may hut: Sii dung may hut khdng khi (Satonus, My) de hut lay 1 m khdng khi tai vi tri trung tam ciia PTN. Cac vi sinh vat thu dUdc tren mang gelatin dUdc nudi cay tren mdi trUdng thich hdp dc xac dinh so lddng, chiing loai va kha nang gay benh.
Tac gia: Trinh Quynh Mai
Dia chi: Vien Ve sinh Dich te Trung Udng, Sd' 1 Yersin. Ha Ndi Dien thoai: 0983110183
E-mail: becky [email protected]
I (id Tap chi Y hpc dir phdng. Tap XX. so 5(113)
1)) [jay mau theo phUdng phap lang bui true tiep cua Koch [1]: Thu thap mau khong khi tai PTN bang each dat cac ctia thach tai 3 vi tri khac nhau (tu an toan sinh hpc. ban thi nghiem va ban lam viec) trong 15 phut. Moi vi tri dat 4 loai moi trUdng: moi trudng dmh dUdng cho vi khuan hieu khi. thach man cho vi khuan (Irani ( + ), thach desoxycholate citrate-DC cho vi khuan Cram (-) va thach sabouraud cho nam.
Cac mau deu chide lay vao mua he.
vao thdi diem tUOng tu nhau. Cac thi nghiem dddc tien hanh 2 lan: bud: sang trddc khi lam vice va budi chieu sau khi ta in viec.
2.2.2. Ky thuat xac dinh cac loai vi sinh vai
a) Xac dinh long so vi sinh vat bieu khi: Nudi cay 37°C trong 48 gid, sau do ddm so khuan lac de xac dinh tdng sd vi khua'n bidu khi
Vdi phUdng phap sii dung may but khdng khi: Dem trite tiep iron dia thach da dan mang gelatin lay tii may hut mau khdng khi sau khi dii hut dii 1 in
Vdi phUdng phap lang bui trUc Ldp trdn dia thach: Tdng sd'vi khuan hieu khi trong 1 m! khdng khi dUdc tinh toim theo cdng thiic Omelianski [ 11:
Tdng sd vi khuan hieu khi trong khdng khi ciia PTN bang so trung binh cdng cuu so khuan lac tren cac dia thach
dat trong PTN sau khi nudi cay.
b) Xac dinh nam (chii yeu la nam Candida albicans), can khuan Cram (+).
va true khuan Cram (-): Salmonella.
Shigella, Escherichia coli va coliform, Pseudomonas theo thddng quy ky thuat cua Vien VSDTTTJ [2].
2.2.3 Xd ly so lieu vd ede lieu chuan danh gid
Cac so lieu dUdc xu" ly bang phan mem SPSS version 15 va Epilnfor 6. So sanh giiia hai sd trung binh dtidc kiem dinh bang Independent-Samples T Tost.
sau khi dii kiem tra phim bd chuan. So sanh giu'a hai ty le du'dc thu'c thien bang kiem dinh Chi-square cd bieu chinh Yatos. Ket qua thu du'dc tii cac thi nghiem du'dc so sanh vdi tieu chuan ciia Siniski ap dung vdi vi khuan trong nha d [3], tieu chuan ciia Komanovic ap dung cho co so san xuat thiic pham, tieu chuan ciia Ginoscova [4] va tieu chuan cua Bp Y td ap dung cho co' sd san xuat vacxin va smh pham [5|.
III. KET QUA
3.1. Kha nang phat bien cac loai vi khuan va nam trong khdng khi
De so sanh kha nang phat bien VSV trong khdng khi cac PTN, cac man khdng khi du'dc thu thap tai 10 PTN nhu nhau.
tai cac thdi diem tUdng tii nhau.
Bang 1. So sanh kha nang phat hien cac loai vi sinh vat trong khdng phi giura 2 phuong phap (n =10)
boai vi khuan Sir dung may hut Sd PTN ( + )
Oat dia thach Sd PTN (+)
Cau khuan gram (+) 8 9
True khuan gram (+) 10 10
True khuan gram (-) 4 5
Nam 10 10
Bang 1 cho thay kha nang phat hien nam va trUc khuan gram dUdng trong khong khi cua 2 phuong phap la nhu nhau, va khong co sU khac biet co y nghia thong ke doi vdi sU phat hien cau khua'n gram dUdng va true khuan gram am. Ke't qua nay la do cac dia thach dUdc dat d nhieu diem trong PTN. chi can 1 diem bat dUdc mot loai VSV nao dd thi loai VSV dd
dddc xac dinh la cd trong PTN dd. Do khdng can phai khao sat tai nhieu diem nen phddng phap lay mau khdng khi bang may hut se net kiem dddc nhieu thdi gian. cdng sUc va vat tU tieu hao hdn so vdi phu'dng phap dat dia thach.
3.2. So sanh ve sd lUcfng vi khuan hieu khi phat hien giira hai phUdng phap
Bang 2. So sanh kha nang phat hien tdng sd vi sinh vat hieu khi/m3 khdng khi (n =10) Phuong phap Nhd nhat Ldn nhat Trung binh Do lech chuan
Budi May hut 21 98 53.2 30,6
sang Oat dTa thach 85 425 218,7 106,7
Budi May hut 29 153 75,3 46,2
chieu Oat dia thach 179 510 284,5 96,6
Sd' lieu so sanh d Bang 2 cho thay sd' lUdng VSV hieu khi xac dinh dUdc bang phUdng phap dat dia thach ldn hdn so vdi phUdng phap hut khdng khi (p <0.0001, Independent-Samples T Test). Ket qua ciia nghien cUu nay cho thay tdng so vi khua'n hieu khi/m' trong PTN d budi song va budi chieu deu thap hdn tdng sd vi khuan hieu khi trong nha/m1 trong nghien ciiu cua cua Tii I lai Bang |6|. Neu chieu theo tieu chuan ciia Siniski ap dung ddi vdi vi khuan trong nha d (khdng khi sach: CFU/m < 1500 vao mUa hd"). tat ca cac phdng xet nghiem deu dddc phan loai d miio dp khdng khi sach.
Trong nghien cuu nay. phddng phap dat dia thach xac dinh sd'lUdng VSV hieu khi ldn hdn cd y nghia thd'ng ke (p <
0.001) so vdi phUdng phap hut khdng khi.
Su khac biet nay cd the do: i) PhUdng phap dat dia thach phu thudc vao rat nhieu yeu td' nhu td'c dd gid. lddng ngUdi lam vice trong PTN. n) Viec bat dddc vi khuan cung rat ngau nhien va phai dung
cdng thiic de tinh toan ra sd CFU/m'.
Trong qua trinh khao sat cd nhiing dia thach dddc md tdi 30 phut nhUng khdng phat hien dUdc mot VSV hieu khi nao trong khi dia thach khac dat d ngay canh.
ciing thdi diem trong thdi gian 10 phut lai bat dddc 2 VSV hieu khi. Mai khac. cac virut va cac vi khuan gay benh thddng tdn tai trong cac tieu phan aerosol nhd.
PhUdng phap dat dia thach chi phat hien dUdc cac tieu phan aerosol lang ddng. cdn cac tieu phan aerosol nhd hdn bay ld liing se khdng phat hien dUdc [6].
Ve mat ky thuat. phUdng phap lay mau sii dung may hut khdng khi khac phuc dUdc nhiing nhUdc diem tren. Hdn niia. vdi lUdng khdng khi dddc hiit da biet trUdc. ngddi linn xet nghiem chi vice dem trUc tiep sd khuan lac tren mdi trUdng nudi cay. Do do. chung tdi gia thuyet rang sd'lUdng vi khuan hieu khi xac dinh dUdc bang phudng phap hiit mau khdng khi cd the dang tin cay hdn so vdi phudng phap dat dia thach. Tuy nhien do phddng phap Tap chi Y hoc du phdng. Tap XX. sd 5(113)
dat dia thach da dddc sti dung va chap nhan rpng rai td nhieu nam nay nen can cd nhiing nghien cu'u tiep theo de khang dinh do tin cay cua phUdng phap sti dung may hut khdng khi.
Do hien nay chUa cd tieu chuan rieng do'i vdi sd' lddng vi khuan cho phep/m'd PTN, chung tdi so sanh cac ket qua tren
theo cac tieu chuan khac nhau. Bang 3 cho thay sd lieu thu dUdc tit hai phddng phap lay mau anh hudng den phan loai ve mile do sach ctia PTN d tat ca cac tieu chuan. Ket qua nay cho thay, vice ap dung cac tieu chuan ddi vdi phUdng phap dat dia thach cho phUdng phap sii dung may hut can dUdc can nhac ky.
Bang 3. Phan loai miic do sach phong thi nghiem theo cac tieu chuan khac nhau (n=10)
Mute do So vi khuan Budi sang Budi chieu
Sach sdng/m3
May hut Dat dia thach May hut Oat dTa thach Tieu chuan Ginoscova
Tot 7.5 0 0 0 0
Vira 30-37.5 5 0 2 0
Kem > 37.5 5 10 8 10
Tieu chuan Romanovic
Rat tot < 20 0 0 0 0
Tot 20-50 5 0 4 0
Vira 50-70 2 0 3 0
Xau > 70 3 10 3 10
Tieu chuan cua Bp Y te
Loai A < 1 0 0 0 0
Loai B Den 5 0 0 0 0
Loai C Den 100 10 0 7 0
Loai D Den 500 0 10 3 10
IV. KET LUAN
Nghien ciiu nay cho thay phudng phap dat dia thach phat hien dUdc nhieu vi khuan hieu khi hon phUdng phap sU dung may hiit khdng khi. tuy nhien sd' lUdng chenh lech nay cung lam thay ddi
sii phan loai d nhiem vi sinh vat theo cac tieu chuan khac nhau ap dung ddi vdi tdng sd vi khuan hieu khi. Ca hai phddng phap deu tudng dUdng nhau ve kha nang phat hien cac vi khuan Gram dUdng.
Gram am va nam.
TAI LIEU THAM KHAO
1. Hoang Thuy Long (1991), Ky thuat xet nghiem vi smh vat y hoc, NXB, Van hoa. Ha Noi.
2. Dao Ngoc Phong (1989), Thu'c tap Ve smh Dich ti, Dai hoc Y Ha Npi. tr 36- 48.
3. Tieu chuan ciia Gmoscova.
4. Bp Y te (2002) Huong dan thdc hanh san xuat diing vac xm va smh pham
Viet Nam. Ha npi.
5. Tit Hai Bang (2003). "Budc dau danh gia chat lu'dng khong khi ve mat vi smh vat tai mot phong thi nghiem vi smh". Ky yeu Hpi nghi khoa hpc quoc te Y hpc lao dong va ve smh moi trUdng lan thd nhat. NXB Y hoc. Ha npi.
6. Bo Qudc phdng- Hoc vien Quan Y (1997). Vi smh vat y hoc. Nhii xuat ban Quan ddi nhan dan. Ha ndi.
COMPARISON OF RESULTS OF DETECTING MICRO-ORGANISMS IN THE AIR BETWEEN THE AGAR PLATE METHOD AND THE VACUUM AIR METHOD
Trinh Quynh Mai. Nguyen Thanh Thuy, I ran Quang Binh, Phan Trong Lan*
National of Hygiene and Epidemiology, Hanoi,
* Ministry of Health
The study that compared the results of detecting microorganisms in the air between the agar plate method and the vacuum air method was conducted at 10 medical and biological laboratories of the Institute of Hygiene and Epidemiology in 2007. Results showed that both methods detected some kinds of micro-organisms
in the air but the greater number of aer- obic bacteria has been collected by the agar plate method than the vacuum air method. These different affects the classi- fication level of microbial contamination according to different standards.
Key words: micro-organism in the air. cleanliness of air, air in laboratory,
Tap chi Y hoc du phdng. Tap XX. sd 5(113)
