医院常见感染菌株分子流行病学及相关因素分析

Nosocomial infective bacteria with different area and climate were carried out to analysis and study the tendency and characteristics of nosocomial outbreak, and to prevent nosocomial before head. Provide genotype of pseudomonas aeruginosa with molecular databases. METHOD: Two hundred and thirty stains of pseudomonas aeruginosa were tested for antibiotic sensitivity. Thirty stains were picked out to be analyzed by pulsed- field gel electrophoresis (PEGF). Twenty-one stains of Enterobacter Cloacae were typed by random amplification of polymorphic DNA (RAPD), PEGF of macro restriction fragments, and repetitive element sequence-based PCR (rep-PCR). Stains were clustered on the basis of Average Matching Coefficient. The discriminatory ability of each typing method was evaluates by Simpson's index of diversity. Forty-four isolates of Proteus spp were genotyped by PFGE, RAPD Rep-PCR and ERIC-PCR. RESULTS: The resistant rates of pseudomonas aeruginosa to carbenicillin piperacillin cefoperaxone cefotaxime ceftriaxone gentamicin tobramycin amikacin ciprofloxacin lomefloxacin polymyxin B ceftazidime ofloxacin norfloxacin are 33.33%, 32.39%, 26.76%, 19.25%, 53.05%, 31.92%, 27.70%, 9.39%, 29.11%, 0.94%, 13.62%, 15.02%, 9.86%, respectively. All of the thirty stains were clustered into three groups at 33.3% similarity level. For Enterobacter Cloacae, the discrimination index of each method is as follows: pulsed- field gel electrophoresis (0.995) random amplification of prolymorphic DNA (0.995), repetitive element sequence-based PCR primer RPUb1 (0.890), primer ERIC2 (0.981), ERICR (1.000). For Proteus, All isolates were types by RAPD with 17 sub-types and the discriminatory power was 0.932,by Rep-PCR with 15 and 0.916, by ERIC-PCR with 23 and 0.941, by PFGE with 36 and 0.988, respectively. CONCLUSION: 1. Ceftazidime is the best antibiotic for pseudomonas aeruginosa infection. No prevalent clone was found in selected area. Stains have no particularity in different areas. Stains have no particularity in different seasons. This may be due to little sample. Stains from the same area and season have no common bands in PFGE profile. This may be explained as that restriction site of Spel if not on that genome. 2. The discriminatory index of these Enterobacter Cloaca typing methods rends as REPUb1-PCR<ERIC2-PCR<AP12H-PCR/ PFGE<ERICR-PCR. ERICR-PCR has the highest discriminatory power. It fragments vary between 0.1-1.2kb in length. And such a narrow range made it difficult to be interpreted. Both AP12h-PCR and PFGE have high discriminatory power. Although PFGE has better reproducibility, but the relative simplicity and low cost of AP12h-PCR make it more suitable for quick typing in outbreak. Primer ERIC2 can be broadly used in different species. It also has high discriminatory power. It may help standardize the among different laboratory. Stains were clustered into different groups by different typing methods. Different typing method may reflect different variation sites of chromosomal DNA. 3. For Proteus, All four genotyping methods of PFGE, RAPD, Rep-PCR and ERIC-PCR showed high type ability and discriminatory power (DI>0.90 all). PFGE was a methods with the highest disiminatory power and reproducibility, but not suitable for large-scale screening due to its disadvantages of high cost and time-consuming. Rep-PCR and ERIC-PCR were relatively more useful than PFGE and RAPD for its stable reproducibility, widely use in several bacterium genuses, easy t implement, low cost and timesaving, although it's discriminatory rate was little less than PFGE and RAPD.

运用分子流行病学、医学统计学、计算机等技术，对大范围、多样本的医院常见感染菌株，进行医院感染发生及流行的环境因素、菌株表型、基因图谱及临床资料等多因素间的相关性研究，初步建立我国医院感染菌的分子流行病学数据库；探索医院感染宏观管理及微观基因多样性规律，模拟出相应数学模型，为医院感染动态预测及监控提供理论和实验依据。.