Savov Encho, Todorova Iva, Politi Lida, Trifonova Angelina, Borisova Maja, Kioseva Elena, Tsakris Athanassios
Laboratory of Microbiology, Military Medical Academy, Sofia, Bulgaria.
Chemotherapy. 2017;62(6):339-342. doi: 10.1159/000464275. Epub 2017 Jul 22.
BACKGROUND/AIMS: Colistin resistance is increasingly recognized among carbapenemase-producing Klebsiella pneumoniae isolates in several European regions. The current study documents the appearance of colistin resistance among KPC-2 and SHV-5-produning K. pneumoniae strains in Bulgaria.
Four colistin-resistant K. pneumoniae isolates were recovered from 2 patients hospitalized in the anesthesiology and resuscitation clinic of a tertiary care university hospital in Sofia, Bulgaria. Microbial identification and antimicrobial susceptibility testing was performed by Vitek 2 (Biomerieux, France). β-Lactamase genes were amplified using a panel of primers for detection of all MBL-types, KPCs, plasmid-mediated AmpCs in single PCR reactions, OXA-type carbapenemases, extended-spectrum β-lactamases (ESBLs) and TEM enzymes. The colistin-resistant mcr-1 gene was also investigated using previously described primers and conditions. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to investigate clonality.
The 4 K. pneumoniae isolates exhibited colistin MICs >16 mg/L and showed multidrug-resistant phenotypes, remaining intermediately susceptible only to gentamicin. They were clustered into a single PFGE clonal type and MLST assigned them to sequence type 258. All isolates possessed KPC-2 carbapenemase and SHV-5 ESBL. They were negative for the plasmid-mediated colistin-resistant mcr-1 gene, possibly implying an intrinsic mechanism of resistance.
Although colistin use in Bulgaria only started moderately during 2014, the findings of the current study notify the appearance of colistin resistance among carbapenemase-producing Klebsiella species in another European region.
背景/目的：在欧洲多个地区，产碳青霉烯酶的肺炎克雷伯菌分离株中对黏菌素耐药的情况日益受到关注。本研究记录了保加利亚产KPC-2和SHV-5的肺炎克雷伯菌菌株中黏菌素耐药的出现情况。
从保加利亚索非亚一家三级护理大学医院麻醉与复苏科住院的2例患者中分离出4株对黏菌素耐药的肺炎克雷伯菌。使用Vitek 2（法国生物梅里埃公司）进行微生物鉴定和抗菌药物敏感性试验。通过一组引物在单个PCR反应中扩增β-内酰胺酶基因，以检测所有MBL型、KPC型、质粒介导的AmpC、OXA型碳青霉烯酶、超广谱β-内酰胺酶（ESBLs）和TEM酶。还使用先前描述的引物和条件研究了对黏菌素耐药的mcr-1基因。采用脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）研究克隆性。
4株肺炎克雷伯菌分离株的黏菌素MIC>16mg/L，呈现多重耐药表型，仅对庆大霉素中度敏感。它们聚为单一的PFGE克隆型，MLST将它们归为序列型258。所有分离株均携带KPC-2碳青霉烯酶和SHV-5 ESBL。它们对质粒介导的黏菌素耐药mcr-1基因呈阴性，可能暗示存在内在耐药机制。
尽管保加利亚在2014年才开始适度使用黏菌素，但本研究结果提示在欧洲另一地区产碳青霉烯酶的克雷伯菌属中出现了黏菌素耐药情况。
