Biofilm formation capacity in CRKP isolates.

BackgroundCarbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a serious problem in hospitals worldwide. We monitored a tertiary hospital in Changchun, Jilin Province, China, and found that CRKP was the major species among the carbapenem-resistant isolates in sewage. Subsequently, we evaluated the drug susceptibility, resistance genes, virulence genes, outer pore membrane protein-related genes (OmpK35 & OmpK 36), multi-locus sequence typing and replicons, biofilm formation capabilities, and resistance to chlorine-containing disinfectants among KP isolates. Identification of drug sensitivity, multiple resistance profiles were observed including 77 (82.80%) multidrug resistant (MDR), 16 (17.20%) extensive drug resistant (XDR). Some antibiotic resistance genes were detected, the most prevalent carbapenemase gene was blaKPC, and 16 resistance genes were associated with other antibiotics. In addition, 3 (3.23%) CRKP isolates demonstrated loss of OmpK-35 and 2 (2.15%) demonstrated loss of OmpK-36. In the detection of multi-locus sequence typing (MLST), 11 ST11 isolates carried virulence genes. The most common replicon type was IncFII. Biofilm-forming capabilities were demonstrated by 68.8% of the isolates, all of which were resistant to chlorine-containing disinfectants. The results of the study showed that antibiotic-resistant isolates, especially CRKP, could resist disinfectants in hospital wastewater, and improper treatment of hospital wastewater may lead to the spread of drug-resistant bacteria and their genes. Thus, these bacteria must be eliminated before being discharged into the municipal sewage system.

背景：耐碳青霉烯类肺炎克雷伯菌（Carbapenem-resistant Klebsiella pneumoniae, CRKP）感染在全球范围内的医院中均为严峻的公共卫生问题。本研究对中国吉林省长春市的一所三级医院开展监测，发现污水来源的耐碳青霉烯类分离株中，CRKP为主要菌种。随后，我们对肺炎克雷伯菌（Klebsiella pneumoniae, KP）分离株的药物敏感性、耐药基因、毒力基因、外膜孔蛋白相关基因（OmpK35与OmpK36）、多位点序列分型（multi-locus sequence typing, MLST）及复制子类型、生物膜形成能力与含氯消毒剂耐受性进行了系统性评估。药敏鉴定结果显示，分离株呈现多重耐药表型：其中77株（82.80%）为多重耐药（multidrug resistant, MDR），16株（17.20%）为广泛耐药（extensive drug resistant, XDR）。研究检出多种抗生素耐药基因，其中流行率最高的碳青霉烯酶基因为blaKPC，另有16种耐药基因与其他类别抗生素的耐药性相关。此外，3株（3.23%）CRKP分离株存在OmpK-35基因缺失，2株（2.15%）存在OmpK-36基因缺失。多位点序列分型（MLST）检测结果表明，11株ST11型分离株携带毒力基因。最常见的复制子类型为IncFII。68.8%的分离株具备生物膜形成能力，且所有具备该能力的分离株均对含氯消毒剂耐受。本研究结果证实，耐药分离株尤其是CRKP，可在医院污水中耐受消毒剂；若医院污水处置不当，可能引发耐药菌及其耐药基因的传播扩散。因此，在医院污水排入市政污水管网前，必须对其中的这类耐药菌进行灭活清除。