Investigation of class 1 integrons in Klebsiella pneumoniae clinical and microbiota isolates belonging to different phylogenetic groups in Recife, State of Pernambuco

Introduction The high prevalence of Klebsiella pneumoniae infections is related to the ability of K. pneumoniae to acquire and disseminate exogenous genes associated with mobile elements, such as R plasmids, transposons and integrons. This study investigated the presence of class 1 integrons in clinical and microbiota isolates of K. pneumoniae belonging to different phylogenetic groups and correlated these results with the antimicrobial resistance profiles of the studied isolates. Methods Of the 51 isolates of K. pneumoniae selected for this study, 29 were from multidrug-resistant clinical isolates, and 22 were from children's microbiota. The susceptibility profile was determined using the disk diffusion method, and class 1 integrons were detected through polymerase chain reaction (PCR). Results The results showed that none of the 22 microbiota isolates carried class 1 integrons. Among the 29 clinical isolates, 19 (65.5%) contained class 1 integrons, and resistance to sulfamethoxazole/trimethoprim was identified in 18 of these isolates (94.7%). Among the K. pneumoniae isolates with class 1 integrons, 47% belonged to the KpI phylogenetic group, and one isolate (14.3%) carrying these genetic elements belonged to the KpIII group. Conclusions The wide variety of detected class 1 integrons supports the presence of high rates of antimicrobial resistance, genetic variability, and rapid dissemination of beta-lactamase genes among K. pneumoniae clinical isolates in recent years in hospitals in Recife-PE, Brazil. The findings of this study indicate that the surveillance of K. pneumoniae integrons in clinical isolates could be useful for monitoring the spread of antibiotic resistance genes in the hospital environment.

引言 肺炎克雷伯菌（Klebsiella pneumoniae）感染的高发病率，与该菌获取并传播与移动遗传元件（如R质粒（R plasmids）、转座子（transposons）、整合子（integrons））相关的外源基因的能力密切相关。本研究针对隶属于不同系统发育群的肺炎克雷伯菌临床分离株与菌群分离株，检测其中1类整合子（class 1 integrons）的存在情况，并将检测结果与受试分离株的抗菌耐药谱进行关联分析。
方法 本研究选取的51株肺炎克雷伯菌分离株中，29株为多重耐药临床分离株，剩余22株来自儿童菌群。采用纸片扩散法测定菌株的药敏谱，通过聚合酶链反应（PCR）检测1类整合子。
结果 22株菌群分离株均未携带1类整合子。29株临床分离株中，19株（65.5%）携带1类整合子，其中18株（94.7%）对磺胺甲恶唑/甲氧苄啶表现出耐药性。在携带1类整合子的肺炎克雷伯菌分离株中，47%隶属于KpI系统发育群，另有1株（14.3%）携带该遗传元件的分离株隶属于KpIII系统发育群。
结论 本次检测到的1类整合子类型多样，这佐证了近年来巴西伯南布哥州累西腓市医院内肺炎克雷伯菌临床分离株中，抗菌耐药率居高不下、遗传多样性丰富，且β-内酰胺酶基因快速传播的现状。本研究结果表明，对临床分离肺炎克雷伯菌的整合子进行监测，有助于监控医院环境中抗生素耐药基因的传播态势。