不同地区铜绿假单胞菌第一类整合子和整合子相关基因盒的分布

目的对石家庄、昆明两地分离的铜绿假单胞菌临床菌株进行第一类整合子的分布及整合子相关基因盒携带率的比较分析，探讨第一类整合子在两地菌株分布的差别。方法采用PCR方法筛选检测64株石家庄、昆明两地临床分离的铜绿假单胞菌第一类整合子和及其所携带的整合子相关基因盒。结果64株铜绿假单胞菌临床菌中共有43株为第一类整合子阳性菌（阳性率67．2％）；其中石家庄菌株和昆明菌株阳性率分别为71．4％和64．3％，两地铜绿假单胞菌第一类整合子阳性率无显著性差异。第一类整合子阳性铜绿假单胞菌中，石家庄菌株和昆明菌株携带一类整合子相关基因盒的阳性率分别为80．0％和38．％，两地第一类整合子阳性菌中整合子相关基因盒的携带率具有显著性差异（P〈0．01）；两地菌株携带的基因盒大小不同。结论第一类整合子在铜绿假单胞菌临床菌株中广泛分布，环境的选择压力影响细菌整合子相关基因盒的分布。

Distribution and identification of class 1 integrons and integrated gene cassettes in clinical Pseudomonas aeruginosa in different geographic regions

Objective The distribution and characterization of the class 1 integrons(int1) and integrated gene cassettes among Pseudonmonas aeruginosa strains from different geographic regions were investigated.Methods 64 clinical strains of P.aeruginosa were isolated from Shijiazhuang and Kunming hospitals,China.The presence and genetic content of int1 and integrated gene cassettes were examined by PCR method.(Results) The incidence of int1 in the 64 clinical isolates of P.aeruginosa was 67.2%(43/64),in which the incidences of int1 carried by the strains from Shijiazhuang and Kunming were 71.4% and 64.3% respectively.Of 43 clinical isolates harboring intI1,27 carried the integrated gene cassttes and 16 were found to lack integrated gene cassttes.The incidences of gene casstte were 80.0% and 38.4% in int1-positive strains from Shijiazhuang and Kunming. Conclusion Results revealed that integron structures were widespread in clinical isolates of(P.aeruginosa).The antibiotic selective pressures play a significant role in the distribution of integrated gene cassettes in bacteria.