Acinetobacter baumannii Sequence Types Harboring Genes Encoding Aminoglycoside Modifying Enzymes and 16SrRNA Methylase; a Multicenter Study from Pakistan

Mohsin Khurshid; Muhammad Hidayat Rasool; Usman Ali Ashfaq; Bilal Aslam; Muhammad Waseem; Muhammad Akhtar Ali; Ahmad Almatroudi; Farhan Rasheed; Muhammad Saeed; Qinglan Guo; Minggui Wang

doi:10.2147/IDR.S260643

Acinetobacter baumannii Sequence Types Harboring Genes Encoding Aminoglycoside Modifying Enzymes and 16SrRNA Methylase; a Multicenter Study from Pakistan

Infect Drug Resist. 2020 Aug 18:13:2855-2862. doi: 10.2147/IDR.S260643. eCollection 2020.

Authors

Affiliations

¹ Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai 200040, People's Republic of China.
² Department of Microbiology, Government College University, Faisalabad, Pakistan.
³ Department of Bioinformatics & Biotechnology, Government College University, Faisalabad, Pakistan.
⁴ School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
⁵ Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia.
⁶ Allama Iqbal Medical College, Jinnah Hospital Lahore, Lahore, Pakistan.

Abstract

Introduction: The aminoglycosides are widely used for the therapeutic management of infections caused by gram-negative bacteria, including the Acinetobacter baumannii strains. However, the resistance to the members of the aminoglycoside family, such as amikacin, gentamicin, and tobramycin, is increasingly being common among the clinical isolates.

Purpose: This study aimed to investigate the presence of 16SrRNA methylases and aminoglycoside modifying enzymes (AMEs) genes among aminoglycoside resistant A. baumannii isolates and to study the genetic diversity of the clinical population of A. baumannii in local hospitals.

Material and methods: The 143 A. baumannii clinical strains were analyzed for antimicrobial susceptibility, genetic screening for enzymes conferring aminoglycosides resistance followed by the multilocus sequence typing.

Results: The 133/143 (93%) isolates were non-susceptible to at least one of the tested aminoglycosides, including amikacin, gentamicin, and tobramycin. The MIC distribution has shown that 87.486.7% strains were resistant to amikacin and gentamicin, respectively. The aphA6, aadB, aacC1, and aphA1 were found in 74.1%, 59.4%, 16.1%, and 11.2% isolates, respectively, whereas the armA was found in 28% of the strains having a higher MIC value (MIC; ≥256µg/mL). The MLST data have shown that the ST589 and ST2 were the most common STs and corresponded to 51 (35.7%) and 38 (26.6%) isolates, respectively, and few of the isolates corresponding to these STs were found to harbor the armA gene with a variable genotypic profile for AMEs.

Discussion: The study has reported the incidence of various enzymes conferring aminoglycoside resistance among the A. baumannii clones for the first time from Pakistan. The findings suggest the possibility of transmission of aminoglycoside resistance determinants through the lateral gene transfer as well as clonal dissemination.

Keywords: A. baumannii; MLST; aminoglycosides; armA; gentamicin.

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (grant # 81773785, 81603163 and 81473250) and Higher Education Commission (HEC) of Pakistan (grant # 5679/Punjab/NRPU/R&D/HEC/2016).