de Cássia Andrade Melo Rita, de Barros Emmily Margate Rodrigues, Loureiro Noel Guedes, de Melo Heloísa Ramos Lacerda, Maciel Maria Amélia Vieira, Souza Lopes Ana Catarina
Departamento de Medicina Tropical, Universidade Federal de Pernambuco, Av. Prof. Morais Rego, s/n., Recife, PE, 50.732-970, Brazil,
Curr Microbiol. 2014 Dec;69(6):824-31. doi: 10.1007/s00284-014-0662-0. Epub 2014 Aug 2.
Klebsiella pneumoniae strains can produce different virulence factors, such as fimbrial adhesins and siderophores, which are important in the colonization and development of the infection. The aims of this study were to determine the occurrence of fimH, mrkD, and irp2 virulence genes in 22 KPC-2-producing K. pneumoniae isolates as well as 22 not producing-KPC isolates, from patients from different hospitals in Recife-PE, Brazil, and also to analyze the clonal relationship of the isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The genes were detected by PCR and DNA sequencing. The bla KPC-2 gene was identified in 22 KPC-positive isolates. On analyzing the antimicrobial susceptibility profile of the isolates, it was detected that polymyxin and amikacin were the antimicrobials of best activity against K. pneumoniae. On the other hand, five isolates exhibited resistance to polymyxin. In the KPC-positive group, was observed a high rate of resistance to cephalosporins, followed by carbapenems. Molecular typing by ERIC-PCR detected 38 genetic profiles, demonstrating a multiclonal spread of the isolates analyzed. It was observed that the virulence genes irp2, mrkD, and fimH were seen to have together a higher frequency in the KPC-positive group. The accumulation of virulence genes of KPC-positive K. pneumoniae isolates, observed in this study, along with the multi-resistance impose significant therapeutic limitations on the treatment of infections caused by K. pneumoniae.
肺炎克雷伯菌菌株可产生不同的毒力因子，如菌毛黏附素和铁载体，这些在感染的定植和发展过程中很重要。本研究的目的是确定来自巴西累西腓不同医院患者的22株产KPC-2的肺炎克雷伯菌分离株以及22株不产KPC的分离株中fimH、mrkD和irp2毒力基因的出现情况，并通过肠杆菌重复基因间共识聚合酶链反应（ERIC-PCR）分析分离株的克隆关系。通过PCR和DNA测序检测这些基因。在22株KPC阳性分离株中鉴定出bla KPC-2基因。在分析分离株的抗菌药物敏感性谱时，发现多黏菌素和阿米卡星是对肺炎克雷伯菌活性最佳的抗菌药物。另一方面，有5株分离株对多黏菌素耐药。在KPC阳性组中，观察到对头孢菌素的耐药率很高，其次是碳青霉烯类。通过ERIC-PCR进行分子分型检测到38种基因图谱，表明所分析的分离株存在多克隆传播。观察到毒力基因irp2、mrkD和fimH在KPC阳性组中共同出现的频率更高。本研究中观察到的产KPC的肺炎克雷伯菌分离株毒力基因的积累，以及多重耐药性，对肺炎克雷伯菌引起的感染治疗造成了重大的治疗限制。
