铜绿假单胞菌多位点序列分析

Multilocus sequence typing analysis of Pseudomonas aeruginosa

目的研究铜绿假单胞菌临床分离株的遗传基因型,明确铜绿假单胞菌携带株的流行特征。方法用多位点序列分型技术(MLST),以铜绿假单胞菌7个管家基因acsA、aroE、guaA、mutL、nuoD、ppsA和trpE的内部特定核酸片段作为检测的靶基因,对60株铜绿假单胞菌的靶基因进行PCR扩增和测序,通过eBURST方法对其进行进化聚类分析,同时通过SplitsTree软件进行菌株基因遗传进化分析。结果 MLST分析显示60株铜绿假单胞菌可分为11个ST型,即ST262、ST195、ST767、ST274、ST527、ST849、ST639、ST871、ST244、ST636和ST645型,未发现新的型别;其中ST244和ST274是优势ST型别,分别占26.67%,18.33%;且ST244型在ICU及呼吸内科数量显著高于其他科室(P<0.05)。结论本地区以ST244和ST274为优势克隆株,尤其在ICU及呼吸内科数量显著高于其他科室,提示医院内存在小范围的传播;MLST对于流行病学研究具有重要意义。

OBJECTIVE To explore the genetic phenotypes of Pseudomonas aeruginosa isolates from clinical speci- mens and to clarify the epidemic characteristics of P. aeruginosa. METHODS All the strains were sequenced by multilocus sequence typing （MLST） using seven house-keeping genes of -P. aeruginosa., acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. The sequencing results were analyzed based on of P. aeruginosa international MLST database to obtain the allelic profiles and sequence types（STs）. The target genes of 60 strains of P. aerug- inosa were amplified and sequenced. The cluster analysis was performed by eBurst method, and the genetic evolu- tion of strains was analyzed by SplitsTree software. RESULTS MLST analysis showed that 60 of P. aeruginosa could be divided into 11 STs, including ST262, ST195, ST767, ST274, ST527, ST849, ST639, ST871, ST244, ST636 and ST645 type, and no new types was found. Among these types, ST244 and ST274 were the dominant STs, accounting for 26.67~ and 18.33~. ST244 type in the ICU and respiratory medicine department was sig- nificantly higher than other departments （P〈0.05）. CONCLUSION ST244 and ST274 were the dominant STs in this region, and the number in the ICU and respiratory medicine department was significantly higher than other departments. There is a small-scale epidemic of nosocomial infections in our hospital. MLST is of great signifi- cance for epidemiological studies.