Dalmolin Tanise Vendruscolo, Bianchini Bianca Vendruscolo, Rossi Grazielle Guidolin, Ramos Ana Carolina, Gales Ana Cristina, Trindade Priscila de Arruda, Campos Marli Matiko Anraku de
Universidade Federal de Santa Maria (UFSM), Laboratório de Micobacteriologia, Santa Maria, RS, Brazil.
Universidade Federal de São Paulo (UNIFESP), Laboratório ALERTA, São Paulo, SP, Brazil.
Braz J Microbiol. 2017 Jul-Sep;48(3):493-498. doi: 10.1016/j.bjm.2017.01.003. Epub 2017 Feb 9.
Carbapenems are considered last-line agents for the treatment of serious infections caused by Klebsiella pneumoniae, and this microorganism may exhibit resistance to β-lactam antibiotics due to different mechanisms of resistance. We evaluated 27 isolates of K. pneumoniae resistant to carbapenems recovered from inpatients at the University Hospital of Santa Maria-RS from July 2013 to August 2014. We carried out antimicrobial susceptibility, carbapenemase detection, testing for the presence of efflux pump by broth microdilution and loss of porin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Genetic similarity was evaluated by ERIC-PCR. High levels of resistance were verified by the minimum inhibitory concentration for the antimicrobials tested. The bla gene was present in 89% of the clinical isolates. Blue-Carba and combined disk with AFB tests showed 100% concordance, while the combined disk test with EDTA showed a high number of false-positives (48%) compared with the gold-standard genotypic test. Four isolates showed a phenotypic resistance profile consistent with the overexpression of the efflux pump, and all clinical isolates had lost one or both porins. The ERIC-PCR dendrogram demonstrated the presence of nine clusters. The main mechanism of resistance to carbapenems found in the assessed isolates was the presence of the bla gene.
碳青霉烯类药物被视为治疗由肺炎克雷伯菌引起的严重感染的最后一线药物，并且这种微生物可能由于不同的耐药机制而对β-内酰胺类抗生素表现出耐药性。我们评估了2013年7月至2014年8月期间从圣玛丽亚-里约格兰德大学医院住院患者中分离出的27株对碳青霉烯类耐药的肺炎克雷伯菌。我们进行了抗菌药物敏感性试验、碳青霉烯酶检测、通过肉汤微量稀释法检测外排泵的存在以及通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳检测孔蛋白的缺失。通过ERIC-PCR评估遗传相似性。通过所测试抗菌药物的最低抑菌浓度验证了高水平的耐药性。bla基因存在于89%的临床分离株中。Blue-Carba和AFB联合纸片试验显示100%的一致性，而与金标准基因分型试验相比，EDTA联合纸片试验显示出大量假阳性（48%）。4株分离株表现出与外排泵过度表达一致的表型耐药谱，并且所有临床分离株均缺失一种或两种孔蛋白。ERIC-PCR树状图显示存在9个聚类。在所评估的分离株中发现的对碳青霉烯类耐药的主要机制是bla基因的存在。
