Association between mutations in GYR A/B and PAR C/E genes of Acinetobacter Baumannii clinical isolates and Fluoroquinolones resistance

Mohamed Elshahat,Esam Aboelized,Ayman Yassin,Raafat Abd El Rahman,Mohamed Nabil

doi:10.21608/mid.2021.64414.1127

Mohamed Elshahat, Esam Aboelized + Show 3 more

Open Access

https://doi.org/10.21608/mid.2021.64414.1127

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Abstract

Background: Acinetobacter baumannii (A. baumannii) is an important organism in hospital acquired infections. A. baumannii has emerged as Quinolones resistant organism.The maximum crucial mechanism of fluoroquinolones resistance is the mutation in genes that encode the subunits of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE). Objectives: determination of mutations of gyrA/B and parC/E genes using Restriction Fragment Length Polymorphism PCR (RFLP - PCR) among fluoroquinolones resistant clinical isolates of A. baumannii showed in ICU patients at Al-Azhar University hospitals. Subjects & Methods: The study was conducted on 100 isolates of A.baumannii which subjected to molecular study of mutations of gyrA, gyrB, parC and parE genes beside determination of minimal inhibitory concentration (MIC). Results: The most A. baumannii isolates had MIC >128 µg/ml (61.1%). The resistant isolates showed combind mutations in both gyrA& parC genes most frequently (79.2%) then gyrA (9.7%), parC (8.3%) and gyrB (2.8%). Conclusion: Mutations in gyrA and parC are the most common in fluoroquinolones resistant A. baumannii isolated from Al-Azhar University hospitals

Highlights

Acinetobacter species are distributed in nature, and have been determined in soil, water, animals, and humans
The isolates of A. baumanii with minimal inhibitory concentration (MIC) more than 128 μg/mL; 44 (61.1%) had combined mutations in the gyrA and parC. These findings indicate that combined mutations are associated with high ciprofloxacin MIC (Table 7)
A baumannii isolates with MIC128 μg/mL had mixed mutations within the gyrA and parC. These findings suggest that mixed mutations are related to excessive MIC resistance to ciprofloxacin

Summary

Introduction

Acinetobacter species are distributed in nature, and have been determined in soil, water, animals, and humans. Some of them can exist for weeks in environment & cause hospital acquired infections [1]. They inhabits in human pores and skin and are often isolated from the throat and respiratory tract of hospitalized patients [2]. Acinetobacter baumannii (A. baumannii) is an important organism in hospital acquired infections. Objectives: Determination of mutations of gyrA/B and parC/E genes using Restriction Fragment Length Polymorphism PCR (RFLP - PCR) among fluoroquinolones resistant clinical isolates of A. baumannii showed in ICU patients at Al-Azhar University hospitals. Methods: The study was conducted on 100 isolates of A.baumannii which were subjected to molecular study of mutations of gyrA, gyrB, parC and parE genes beside determination of minimal inhibitory concentration (MIC). Conclusions: Mutations in gyrA and parC are the most common in fluoroquinolones resistant A. baumannii isolated from AlAzhar University hospitals

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