Carbapenems are employed to treat infections caused by Gram-negative bacteria including Klebsiella pneumoniae. This research is aimed to perform phenotypic detection of β-lactamases and molecular characterization of NDM-1 positive K. pneumoniae isolates. Another objective is to investigate NDM-1 producing K. pneumoniae among children in Iran. From 2019 to 2020, altogether 60 K. pneumoniae isolates were acquired from various patients in certain Iranian hospitals. Antimicrobial susceptibility testing was performed by disk diffusion and broth microdilution methods. In addition, mCIM and eCIM were used to confirm the production of carbapenemases and metallo-beta-lactamases (MBLs), respectively. Detection of resistance genes namely, blaNDM-1, blaIMP, blaVIM, blaKPC, blaOXA-48-like, blaCTX-M, blaSHV, blaTEM, and mcr-1 was performed by PCR and confirmed by DNA sequencing. Multilocus sequence typing (MLST) was employed to determine the molecular typing of the strains. According to the findings, the highest rate of carbapenem resistance was detected against doripenem 83.3% (50). Moreover, 31.7% (19) were resistant to colistin. Further to the above, altogether 80% (48) were carbapenemase-producing isolates and among them 46.7% (28) of the isolates were MBL and 33.3% (20) isolates were serine β-lactamase producer. According to the PCR results, 14 isolates produced blaNDM-1. Remarkably, four blaNDM-1 positive isolates were detected in children. In addition, these isolates were clonally related as determined by MLST (ST147, ST15). Altogether ten blaNDM-1 positive isolates were ST147 and four blaNDM-1 positive isolates were ST15. Based on the results, the emergence of NDM-producing K. pneumoniae among children is worrying and hence, it is necessary to develop a comprehensive program to control antibiotic resistance in the country.

中文翻译：

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2019-2020 年伊朗产 NDM-1 肺炎克雷伯菌 ST15 和 ST147 的检测。


碳青霉烯类用于治疗由革兰氏阴性菌（包括肺炎克雷伯菌）引起的感染。本研究旨在对 NDM-1 阳性肺炎克雷伯菌分离株进行 β-内酰胺酶的表型检测和分子表征。另一个目标是调查伊朗儿童中产生 NDM-1 的肺炎克雷伯菌。 2019年至2020年，伊朗某些医院从不同患者身上总共获得了60株肺炎克雷伯菌分离株。通过纸片扩散和肉汤微量稀释方法进行抗菌药物敏感性测试。此外，mCIM 和 eCIM 分别用于确认碳青霉烯酶和金属-β-内酰胺酶 (MBL) 的产生。通过PCR检测抗性基因，即blaNDM-1、blaIMP、blaVIM、blaKPC、blaOXA-48-like、blaCTX-M、blaSHV、blaTEM和mcr-1，并通过DNA测序确认。采用多位点序列分型（MLST）来确定菌株的分子分型。结果显示，碳青霉烯类耐药率最高的是多尼培南，达83.3%（50）。此外，31.7%（19）对粘菌素有耐药性。除此之外，总共80%（48）株产碳青霉烯酶，其中46.7%（28）株产MBL，33.3%（20）株产丝氨酸β-内酰胺酶。 PCR结果显示，14株菌株产生blaNDM-1。值得注意的是，在儿童中检测到了四种 blaNDM-1 阳性分离株。此外，根据 MLST（ST147、ST15）确定，这些分离株具有克隆相关性。总共 10 个 blaNDM-1 阳性分离株为 ST147，4 个 blaNDM-1 阳性分离株为 ST15。根据这些结果，产生 NDM 的 K. 儿童肺炎令人担忧，因此有必要制定一项全面的计划来控制该国的抗生素耐药性。