Background Klebsiella pneumoniae has been responsible for a large number of clonal hospital outbreaks. However, some epidemiological changes have been observed since the emergence of CTX-M enzymes in K. pneumoniae. Aim To analyse the transmission dynamics of Extended Spectrum β-Lactamase-producing Klebsiella pneumoniae (ESBL-Kp) in an acute care hospital. Methods In 2015 a prospective cohort study was conducted. All new consecutive adult patients with ESBL-Kp isolates in all clinical samples were included. Patients with a previous known infection/colonization by ESBL-Kp and patients in high risk areas (e.g., intensive care units) were excluded. Cross-transmission was defined as the carriage of a clonally-related ESBL-Kp between newly diagnosed patients who shared the same ward for ≥48 h with another case, within a maximum time window of 4 weeks. ESBL-production was confirmed using the double-disk diffusion method and PCR. Clonal relationships were investigated by rep-PCR and multilocus sequence typing (MLST). Results Sixty ESBL-Kp isolates from 60 patients were included and analysed. Infections and colonizations were classified as hospital-acquired (52%), healthcare-related (40%) or community-acquired (8%).High genetic diversity was detected. When epidemiological clinical data were combined with the rep-PCR, the patterns identified did not show any cases of cross-transmission. ESBL-Kp were detected in 12.5% of environmental samples. No clonal relationship could be established between environmental reservoirs and patients. The genetic mechanism detected in all strains was associated with bla CTX-M genes, and 97% were CTX-M-15. Conclusions The dynamics of ESBL-K. pneumoniae isolated in our setting could not be explained by clonal transmission from an index patient. A polyclonal spread of ESBL-Kp was identified.

中文翻译：

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从非疫情情况下的临床样本中分离出的产 ESBL 肺炎克雷伯菌具有高度克隆多样性。一项队列研究。

背景 肺炎克雷伯菌是造成大量克隆性医院暴发的原因。然而，自从肺炎克雷伯菌中出现 CTX-M 酶以来，已经观察到一些流行病学变化。目的 分析急诊医院中产超广谱 β-内酰胺酶肺炎克雷伯菌 (ESBL-Kp) 的传播动态。方法 2015年进行了一项前瞻性队列研究。所有临床样本中所有新的连续成年患者均含有 ESBL-Kp 分离株。先前已知 ESBL-Kp 感染/定植的患者和高风险地区（例如重症监护病房）的患者被排除在外。交叉传播被定义为新诊断患者与另一病例共用同一病房≥48小时（最长时间窗口为4周）之间携带克隆相关ESBL-Kp。使用双盘扩散法和 PCR 确认 ESBL 的产生。通过rep-PCR 和多位点序列分型（MLST）研究克隆关系。结果 纳入并分析了来自 60 名患者的 60 株 ESBL-Kp 分离株。感染和定植分为医院获得性（52%）、医疗保健相关（40%）或社区获得性（8%）。检测到高遗传多样性。当流行病学临床数据与rep-PCR结合时，发现的模式没有显示任何交叉传播的病例。12.5% 的环境样品中检测到 ESBL-Kp。环境宿主和患者之间无法建立克隆关系。所有菌株检测到的遗传机制均与bla CTX-M基因相关，其中97%为CTX-M-15。结论 ESBL-K 的动力学。在我们的环境中分离出的肺炎链球菌不能用指示患者的克隆传播来解释。鉴定出 ESBL-Kp 的多克隆传播。