Objectives

The aim of this study has been to characterize carbapenem-resistant Klebsiella pneumoniae isolates and to determine the resistance mechanisms involved, the clonal relationship between strains and clinical and demographical data of the infected patients.

Methods

Clinical and demographical data from patients were collected and statistically analysed. Antimicrobial susceptibility testing was performed and resistance genes were detected both phenotypically and genotypically. Conjugation assays were performed to show horizontal transferability of resistance genes. Clonal relationship was also studied. Next-generation sequencing (NGS) was performed to obtain information regarding resistance genes, sequence types, virulence factors and plasmid types.

Results

Statistical significance was shown by the presence of an infection if there had been a previous hospital stay; urinary catheter carriage and chronic renal disease also indicated higher probabilities of being infected. More than 95% of the isolates were non-susceptible to third-generation cephalosporins, and more than 90% were non-susceptible to quinolones. Phenotypic and genotypic methods for resistance detection were concordant and later confirmed by NGS. This is the first detection of OXA-48, NDM-1 and CTX-M-15 co-production in the area. No plasmid-mediated colistin resistance was found. Tetracycline, sulfonamides and aminoglycoside resistance genes were found in almost all the isolates studied. No virulence factors were detected. Multilocus sequence typing showed more than 15 different sequence types, with ST101, ST307 and ST11 being the most prevalent.

Conclusions

This study is the first to report such a large group of OXA-48 carbapenemases with clonal dissemination among carbapenem-resistant K. pneumoniae in Valencia. This is also the first detection of OXA-48, NDM-1 and CTX-M-15 co-production in the area.

中文翻译：

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西班牙巴伦西亚一家三级医院患者对碳青霉烯类耐药的肺炎克雷伯菌的分子流行病学和耐药机制。

目标

这项研究的目的是鉴定耐碳青霉烯的肺炎克雷伯菌菌株，并确定涉及的耐药机制，菌株之间的克隆关系以及感染患者的临床和人口统计学数据。

方法

收集患者的临床和人口统计学资料并进行统计分析。进行了抗生素敏感性试验，并在表型和基因型上检测了耐药基因。进行缀合测定以显示抗性基因的水平转移性。还研究了克隆关系。进行了下一代测序（NGS），以获得有关抗性基因，序列类型，毒力因子和质粒类型的信息。

结果

如果以前曾住院过，则感染的存在显示出统计学意义；导尿管和慢性肾脏疾病也表明感染的可能性更高。超过95％的分离株对第三代头孢菌素不敏感，超过90％对喹诺酮不敏感。耐药性检测的表型和基因型方法是一致的，后来被NGS确认。这是该地区首次检测到OXA-48，NDM-1和CTX-M-15联合生产。未发现质粒介导的粘菌素抗性。在几乎所有研究的分离物中都发现了四环素，磺酰胺和氨基糖苷抗性基因。未检测到毒力因子。多基因座序列分型显示出超过15种不同的序列类型，其中ST101，

结论

这项研究是首次报道如此大量的OXA-48碳青霉烯酶，并在巴伦西亚耐碳青霉烯的肺炎克雷伯菌中散播。这也是该地区首次检测到OXA-48，NDM-1和CTX-M-15联合生产。