Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, China.
J Infect Dis. 2020 Mar 16;221(Suppl 2):S206-S214. doi: 10.1093/infdis/jiz622.
Carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a threat to public health, most notably as a superbug causing nosocomial infections. Patients in the intensive care unit (ICU) are at increased risk of hospital-acquired K pneumoniae infection, especially CRKP. This study was conducted to investigate the frequency of gastrointestinal and nasopharyngeal K pneumoniae colonization and its contribution to infections in ICU patients.
A 3-month prospective cohort study was performed in which 243 ICU patients were screened for intestinal and nasopharyngeal carriage of K pneumoniae at admission and once per week thereafter. The colonization and clinical infection isolates were analyzed by antimicrobial susceptibility testing to identify CRKP and were characterized by multilocus sequence typing (MLST) and whole-genome sequencing combined with epidemiological data to investigate the resistance mechanisms and assess the possible transmitted infection.
Twenty-eight percent (68 of 243) of patients tested positive for carriage of K pneumoniae immediately upon admission to ICU, 54% (37 of 68) of which were nonduplicate CRKP isolates. Patients with carbapenem-susceptible K pneumoniae (CSKP) colonization at admission were more likely to acquire CRKP colonization during the ICU stay compared with patients without K pneumoniae colonization at admission. The incidence of subsequent CRKP infection in the baseline CSKP (32.3%, 10 of 31) and CRKP (45.9%, 17 of 37) carrier group was significantly higher than that of the baseline non-KP carrier group (8.6%, 15 of 175). The risk factors associated with acquired CRKP colonization during the ICU stay among negative CRKP colonization at admission included previous exposure to carbapenem, tigecycline or β-lactam/β-lactamases inhibitor, and invasive processes or surgical operations. Sixty-four percent (27 of 42) of patients with K pneumoniae infection were colonized by clonally related K pneumoniae strains according to enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction analysis. ST11 (72%, 53 of 74) was the most predominant MLST type of clonally related CRKP isolate colonizing these patients, followed by ST15 (26%, 19 of 74).
The colonization of K pneumoniae may increase the incidence of corresponding K pneumoniae infection in critically ill patients in the ICU. High prevalence of ST11 CRKP (due to blaKPC-2) carriage and infection in ICU was observed.
耐碳青霉烯类肺炎克雷伯菌（CRKP）已成为公共卫生的威胁，尤其是作为一种引起医院获得性感染的超级细菌。重症监护病房（ICU）的患者感染医院获得性肺炎克雷伯菌的风险增加，尤其是耐碳青霉烯类肺炎克雷伯菌。本研究旨在调查 ICU 患者胃肠道和鼻咽部肺炎克雷伯菌定植的频率及其对感染的贡献。
进行了一项为期 3 个月的前瞻性队列研究，其中 243 名 ICU 患者在入院时和此后每周进行一次肠道和鼻咽部携带肺炎克雷伯菌的筛查。通过药敏试验对定植和临床感染分离株进行分析，以确定耐碳青霉烯类肺炎克雷伯菌，并通过多位点序列分型（MLST）和全基因组测序结合流行病学数据对其进行特征分析，以研究耐药机制并评估可能的传播感染。
243 名患者中，28%（68 名）在入住 ICU 时立即检测到肺炎克雷伯菌定植阳性，其中 54%（37 名）为非重复耐碳青霉烯类肺炎克雷伯菌分离株。与入院时无肺炎克雷伯菌定植的患者相比，入院时耐碳青霉烯类肺炎克雷伯菌定植的患者在 ICU 期间更有可能获得耐碳青霉烯类肺炎克雷伯菌定植。在基线耐碳青霉烯类肺炎克雷伯菌（32.3%，10/31）和耐碳青霉烯类肺炎克雷伯菌（45.9%，17/37）定植组中，随后发生耐碳青霉烯类肺炎克雷伯菌感染的发生率明显高于基线非肺炎克雷伯菌定植组（8.6%，15/175）。在入院时耐碳青霉烯类肺炎克雷伯菌阴性定植的患者中，与 ICU 期间获得耐碳青霉烯类肺炎克雷伯菌定植相关的危险因素包括先前接触碳青霉烯类、替加环素或β-内酰胺/β-内酰胺酶抑制剂以及侵入性操作或手术。64%（27/42）的肺炎克雷伯菌感染患者根据肠杆菌重复基因间 consensus 序列-聚合酶链反应分析被克隆相关的肺炎克雷伯菌菌株定植。ST11（72%，53/74）是定植于这些患者的克隆相关耐碳青霉烯类肺炎克雷伯菌分离株的最主要 MLST 型，其次是 ST15（26%，19/74）。
肺炎克雷伯菌的定植可能会增加 ICU 危重症患者发生相应肺炎克雷伯菌感染的几率。在 ICU 中观察到耐碳青霉烯类肺炎克雷伯菌（由于 blaKPC-2）携带和感染的 ST11 高流行率。
