Laboratório de Difteria e Corinebactérias de Importância Clínica, Faculdade de Ciências Médicas, Centro Colaborador e Referência para pesquisa de Difteria/Ministério da Saúde, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brazil.
Instituto Nacional de Controle de Qualidade em Saúde, Fundação Oswaldo Cruz, INCQS/FIOCRUZ, Rio de Janeiro, Brazil.
BMC Infect Dis. 2019 Jul 29;19(1):672. doi: 10.1186/s12879-019-4294-7.
Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.
C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.
Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.
Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.
棒状杆菌属是一种新兴的多药耐药（MDR）病原体，与免疫功能低下和慢性疾病患者以及医院内爆发有关。在这项研究中，我们对来自里约热内卢一家医院的血流感染和导管相关感染的 23 株 MDR 棒状杆菌属进行了特征描述。
通过 16S rRNA 和 rpoB 基因测序鉴定棒状杆菌属分离株。通过脉冲场凝胶电泳（PFGE）传播这些分离株。所有分离株均通过纸片扩散法和 E 试验条法进行最低抑菌浓度法进行药敏试验。通过聚合酶链反应检测抗菌药物耐药基因。在四种不同的非生物表面上进行定量测试，并通过扫描电子显微镜证明了在聚氨酯和硅酮导管表面产生生物膜的能力。
发现了 11 种 PFGE 图谱。PFGE 图谱 I 是在分离株中最常观察到的。发现了 5 种不同的 MDR 图谱，所有 PFGE 图谱 I 分离株仅对四环素、万古霉素、利奈唑胺和达托霉素敏感。只有多药敏感的分离株在喹诺酮类药物耐药决定区（QRDR）的 gyrA 基因中没有发现突变，并且在寻找编码抗生素耐药的基因时呈阴性。其他 22 株分离株对氨基糖苷类、大环内酯类/林可酰胺类和氯霉素耐药基因呈阳性，并且在 gyrA 基因的 QRDR 中存在突变。扫描电子显微镜说明了流行克隆（PFGE 图谱 I）的 MDR 血液分离株在聚氨酯和硅酮导管表面形成成熟生物膜的能力。
通过 PFGE 进行基因分型分析表明，MDR PFGE 图谱 I 存在于医院环境中。其他新的 PFGE 图谱作为侵袭性感染的病原体出现。然而，MDR PFGE 图谱 I 也在血液源性感染患者中占主导地位。观察到的 MDR 棒状杆菌属高水平的多药耐药性与生物膜形成能力相关，这是一个令人关注的问题。
