铜绿假单胞菌对碳青霉烯类和氨基糖苷类药物的严重耐药性：具有固有耐药机制的 bla/16S 甲基化酶 armA 携带株在伊朗克尔曼的传播。

Critical resistance to carbapenem and aminoglycosides in Pseudomonas aeruginosa: spread of bla/16S methylase armA harboring isolates with intrinsic resistance mechanisms in Kerman, Iran.

机构信息

Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman, Iran.

Department of Medical Microbiology (Bacteriology and Virology), Afzalipour Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.

出版信息

BMC Infect Dis. 2024 Oct 21;24(1):1188. doi: 10.1186/s12879-024-10085-w.

DOI:10.1186/s12879-024-10085-w

PMID:39434025

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11494745/

Abstract

BACKGROUND

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is one of the main Gram-negative bacterium causes of infections in hospital settings, and the spread of them is a significant challenge to public health.

METHODS

A total of 30 non-duplicate isolates of CRPA were collected. Antibacterial susceptibility of isolates to antibiotic agents, AmpC β-lactamase production, and biofilm formation were determined. Minimum biofilm inhibitory concentrations (MBIC) of isolates to cefepime (FEP), imipenem (IPM), ceftazidime (CAZ), and meropenem (MEM) were evaluated with/without cloxacillin (CLX). The carbapenemase and 16 S rRNA methylase genes were identified by PCR, and the transcription levels of oprD, ampC, and mexA genes were determined by quantitative real-time PCR (qPCR). ERIC-PCR was used to detect genetic relationships among isolates.

RESULTS

All isolates were multidrug resistant (MDR) and strong biofilm producers. The resistance genes including bla, bla, bla, bla, bla and armA were detected in 21 (70%), 6 (20%), 3 (10%), 2 (6.6%), 1 (3.3%), and 17 (56.6%) of the isolates, respectively. CLX at 500 and 1000 µg/mL significantly reduced the level of MIC to MEM, IPM, CAZ, and FEP, also at 2000 µg/mL significantly reduced the level of MBIC to MEM, IPM, CAZ, and FEP. In all isolates, the transcription levels of oprD were significantly downregulated as well as significantly increased for ampC and mexA. ERIC-PCR typing results divided 30 isolates into four clusters A to D.

CONCLUSION

In this study, we reported the spread of different clones of CRPA harboring co-existence of various carbapenemase genes with armA 16 S rRNA methylase for the first time in Kerman, Iran. Also, our isolates had several mechanisms of resistance to carbapenems as well as ability biofilm formation along with resistance to aminoglycosides, the further spread of which could cause serious challenges in our hospital settings. Therefore, serious monitoring is necessary to reduce their prevalence.

摘要

背景

耐碳青霉烯铜绿假单胞菌（CRPA）是医院环境中主要的革兰氏阴性菌感染病原体之一，其传播对公共卫生构成重大挑战。

方法

共收集了 30 株非重复的耐碳青霉烯铜绿假单胞菌分离株。测定分离株对抗生素的药敏性、AmpC β-内酰胺酶的产生和生物膜的形成。在有/无氯唑西林（CLX）的情况下，评估分离株对头孢吡肟（FEP）、亚胺培南（IPM）、头孢他啶（CAZ）和美罗培南（MEM）的最小生物膜抑制浓度（MBIC）。通过 PCR 鉴定碳青霉烯酶和 16S rRNA 甲基酶基因，并通过实时定量 PCR（qPCR）测定 oprD、ampC 和 mexA 基因的转录水平。ERIC-PCR 用于检测分离株之间的遗传关系。

结果

所有分离株均为多药耐药（MDR）和强生物膜产生者。在 21 株（70%）、6 株（20%）、3 株（10%）、2 株（6.6%）、1 株（3.3%）和 17 株（56.6%）的分离株中检测到 blaCTX-M、blaGES、blaDHA、blaVIM、blaIMP 和 armA 耐药基因。CLX 在 500 和 1000μg/mL 时，可显著降低 MEM、IPM、CAZ 和 FEP 的 MIC 水平，在 2000μg/mL 时，可显著降低 MEM、IPM、CAZ 和 FEP 的 MBIC 水平。在所有分离株中，oprD 的转录水平均显著下调，ampC 和 mexA 的转录水平显著上调。ERIC-PCR 分型结果将 30 株分离株分为 A 至 D 四个聚类。

结论

本研究首次在伊朗克尔曼报道了不同克隆的耐碳青霉烯铜绿假单胞菌的传播，这些克隆同时携带多种碳青霉烯酶基因和 16S rRNA 甲基酶 armA。此外，我们的分离株对碳青霉烯类药物具有多种耐药机制，同时对氨基糖苷类药物也具有耐药性，其进一步传播可能会在我们的医院环境中造成严重挑战。因此，有必要进行严格监测以降低其流行率。