Pereira Rito Santo, Dias Vanessa Cordeiro, Ferreira-Machado Alessandra Barbosa, Resende Juliana Alves, Bastos André Netto, Andrade Bastos Lucas Quinet, Andrade Bastos Victor Quinet, Bastos Ricardo Villela, Da Silva Vânia Lúcia, Diniz Cláudio Galuppo
Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.
J Infect Dev Ctries. 2016 Jun 30;10(6):592-9. doi: 10.3855/jidc.6821.
Bacterial resistance is a growing concern in the nosocomial environment in which Klebsiella pneumoniae and Enterobacter aerogenes play an important role due to their opportunism and carbapenemase-production. This work aimed to evaluate physiological and molecular characteristics of carbapenem-resistant K. pneumoniae and E. aerogenes isolated in a Brazilian tertiary hospital.
In total, 42 carbapenem-resistant bacteria isolated from clinical specimens were included (21 K. pneumoniae and 21 E. aerogenes). Drug-sensitive K. pneumoniae (n = 27) were also included. Antimicrobial susceptibility and biocide tolerance patterns, hemolytic activity, tolerance to oxidative stress, and aggregative ability were assessed. Genetic markers related to carbapenem resistance, or ESBL-production were screened by PCR.
Compared to drug-sensitive strains, carbapenem-resistant K. pneumoniae were more tolerant to biocides and to oxidative stress, and they displayed an increase in biofilm formation. The genetic markers blaKPC (95.2%) and blaTEM (90.5%) were the most frequent. Among the carbapenem-resistant E. aerogenes strains, blaKPC, and blaTEM were detected in all bacteria. Drug-sensitive E. aerogenes were not isolated in the same period. blaSHV, blaVIM, and blaCTX markers were also observed among carbapenem-resistant bacteria.
Results suggest that carbapenemase-producing enterobacteria might show peculiar characteristics regarding their physiology associated with their environmental persistency, virulence, and multidrug resistance. The observed phenomenon may have implications not only for antimicrobial chemotherapy, but also for the prognosis of infectious diseases and infection control.
细菌耐药性在医院环境中日益受到关注，其中肺炎克雷伯菌和产气肠杆菌因其机会致病性和碳青霉烯酶产生而发挥重要作用。本研究旨在评估巴西一家三级医院分离出的耐碳青霉烯肺炎克雷伯菌和产气肠杆菌的生理和分子特征。
共纳入42株从临床标本中分离出的耐碳青霉烯细菌（21株肺炎克雷伯菌和21株产气肠杆菌）。还纳入了药敏肺炎克雷伯菌（n = 27）。评估了抗菌药物敏感性和杀菌剂耐受性模式、溶血活性、对氧化应激的耐受性以及聚集能力。通过PCR筛选与碳青霉烯耐药或超广谱β-内酰胺酶（ESBL）产生相关的基因标记。
与药敏菌株相比，耐碳青霉烯肺炎克雷伯菌对杀菌剂和氧化应激更具耐受性，且其生物膜形成增加。基因标记blaKPC（95.2%）和blaTEM（90.5%）最为常见。在耐碳青霉烯产气肠杆菌菌株中，所有细菌均检测到blaKPC和blaTEM。同期未分离出药敏产气肠杆菌。在耐碳青霉烯细菌中也观察到blaSHV、blaVIM和blaCTX标记。
结果表明，产碳青霉烯酶的肠杆菌在与其环境持久性、毒力和多重耐药性相关的生理学方面可能表现出独特特征。观察到的现象不仅可能对抗菌化疗有影响，而且可能对传染病的预后和感染控制有影响。
