Vardhman Mahavir Medical College & Safdarjung Hospital, New Delhi, 110029, India.
National Institute of Animal Biotechnology-DBT, Hyderabad, 500049, India.
BMC Infect Dis. 2019 Aug 14;19(1):717. doi: 10.1186/s12879-019-4368-6.
Coagulase-negative Staphylococci (CoNS) have emerged as a major causative agent of blood-stream infections (BSI). Linezolid (LZD) is currently used for treating glycopeptide and methicillin-resistant staphylococci. It is important to understand the resistance mechanism and probable transmission of LZD resistant (LR) CoNS within the hospital.
Clinically significant LRCoNS from patients with BSI were characterized using MALDI-TOF and 16S rRNA gene sequence analysis. Antimicrobial susceptibility and MIC of vancomycin and LZD were determined. LZD resistance mechanisms using PCR for the cfr gene and mutation in the V domain of the 23S rRNA gene were studied.
The MIC of LZD ranged from 8 to 32 μg/ml. LR was observed in three different CoNS species from diverse locations within the hospital. The cfr gene was identified in all the isolates. Sequence analysis of V domain region of 23S rRNA gene confirmed mutation in single copy among 12/15 isolates with novel mutations: G2614 T and C2384T. All infections were nosocomially acquired and LZD resistance was emerging in the absence of prior LZD use. Horizontal spread of resistant isolates and cfr gene among diverse species were the probable mechanisms of transmission.
The study highlights the novel mutations associated with LRCoNS and the importance of surveillance & transmission pathway within the hospital. It also systematically discusses the published information on LRCoNS.
凝固酶阴性葡萄球菌（CoNS）已成为血流感染（BSI）的主要病原体。利奈唑胺（LZD）目前用于治疗糖肽类和耐甲氧西林葡萄球菌。了解 LZD 耐药（LR）CoNS 在医院内的耐药机制和可能的传播途径非常重要。
对来自 BSI 患者的临床显著 LRCoNS 进行 MALDI-TOF 和 16S rRNA 基因序列分析。测定万古霉素和 LZD 的药敏性和 MIC。通过 PCR 检测 cfr 基因和 23S rRNA 基因 V 区突变研究 LZD 耐药机制。
LZD 的 MIC 范围为 8 至 32μg/ml。在医院内不同位置的三种不同 CoNS 物种中观察到 LR。所有分离株均鉴定出 cfr 基因。23S rRNA 基因 V 区序列分析证实 12/15 个分离株中有单拷贝突变：G2614T 和 C2384T。所有感染均为医院获得性感染，在没有先前使用 LZD 的情况下出现 LZD 耐药。耐药分离株和 cfr 基因在不同物种之间的水平传播可能是传播的机制。
该研究强调了与 LRCoNS 相关的新突变以及医院内监测和传播途径的重要性。它还系统地讨论了关于 LRCoNS 的已发表信息。
