在一所教学医院中，产 AmpC 型β-内酰胺酶和同时产超广谱β-内酰胺酶的大肠埃希菌和克雷伯菌属的流行率。

Prevalence of AmpC beta-lactamase and extended spectrum beta-lactamase co-producer in Escherichia coli and Klebsiella species in a teaching hospital.

机构信息

Universiti Kebangsaan Malaysia, Faculty of Medicine, Department of Medical Microbiology and Immunology, Kuala Lumpur, Malaysia.

出版信息

Malays J Pathol. 2024 Apr;46(1):79-89.

PMID:38682847

Abstract

INTRODUCTION

Beta-lactamase producing bacterial infection has been on surge due to selection pressure and injudicious antibiotics usage. Organisms that co-produced more than one beta lactamase enzyme posed diagnostic challenges which may result in inadequate treatment. To date, there is no standardised guideline offering phenotypic detection of AmpC β-lactamase. The purpose of this study was to determine the prevalence of ESBLs, AmpC β-lactamase and co-producer organisms in a teaching hospital.

MATERIALS AND METHODS

Three hundred and four isolates of E. coli and Klebsiella sp. had been selected via convenient sampling. These isolates were identified using conventional laboratory methods and their antimicrobial susceptibilities were determined using disc diffusion method. Those isolates were then proceeded with ESBL confirmatory test, cloxacillin-containing Muller Hinton confirmatory test, modified double disk synergy test and AmpC disk test.

RESULTS

Out of 304 isolates, 159 isolates were E. coli and 145 were Klebsiella sp. The prevalence of organisms which co-produced AmpC β-lactamase and ESBL enzymes were 3.0%. Besides that, 39 cefoxitin resistant and three cefoxitin susceptible isolates (13.8%) were proven to produce AmpC β-lactamase through AmpC disk test. Through the CLSI confirmatory test, 252 (82.9%) isolates were identified as ESBLs producers and the prevalence increased slightly when cloxacillin-containing Muller Hinton were used. Only three ESBLs positive organisms were positive for modified double disk synergy test.

CONCLUSION

Distinguishing between AmpC β-lactamase and ESBL-producing organisms has epidemiological significance as well as therapeutic importance. Moreover, AmpC β-lactamase and ESBLs co-producing organisms can lead to false negative ESBL confirmatory test. Therefore, knowing the local prevalence can guide the clinician in navigating the treatment.

摘要

简介

由于选择压力和不合理使用抗生素，产β-内酰胺酶的细菌感染呈上升趋势。同时产生一种以上β-内酰胺酶的生物体带来了诊断挑战，可能导致治疗不足。迄今为止，尚无标准指南提供表型检测 AmpC β-内酰胺酶。本研究旨在确定教学医院中 ESBL、AmpC β-内酰胺酶和共产生体的流行情况。

材料和方法

通过便利抽样选择了 304 株大肠埃希菌和克雷伯菌。使用常规实验室方法对这些分离株进行鉴定，并使用纸片扩散法测定其抗菌药物敏感性。然后对这些分离株进行 ESBL 确认试验、含氯唑西林的 Muller Hinton 确认试验、改良双盘协同试验和 AmpC 盘试验。

结果

在 304 株分离株中，159 株为大肠埃希菌，145 株为克雷伯菌。同时产 AmpC β-内酰胺酶和 ESBL 酶的生物体的流行率为 3.0%。此外，通过 AmpC 盘试验，39 株头孢西丁耐药和 3 株头孢西丁敏感的分离株（13.8%）被证明产生 AmpC β-内酰胺酶。通过 CLSI 确认试验，252 株（82.9%）分离株被鉴定为 ESBL 产生菌，当使用含氯唑西林的 Muller Hinton 时，流行率略有增加。只有三种 ESBL 阳性的生物体对改良的双盘协同试验呈阳性。