Insights into mobile genetic elements and the role of conjugative plasmid in transferring aminoglycoside resistance in extensively drug-resistant Acinetobacter baumannii AB329

Supat Khongfak; Rapee Thummeepak; Udomluk Leungtongkam; Kannipa Tasanapak; Aunchalee Thanwisai; Sutthirat Sitthisak

doi:10.7717/peerj.13718

Insights into mobile genetic elements and the role of conjugative plasmid in transferring aminoglycoside resistance in extensively drug-resistant Acinetobacter baumannii AB329

PeerJ. 2022 Jul 13:10:e13718. doi: 10.7717/peerj.13718. eCollection 2022.

Authors

Supat Khongfak¹, Rapee Thummeepak¹, Udomluk Leungtongkam¹, Kannipa Tasanapak¹, Aunchalee Thanwisai¹, Sutthirat Sitthisak^{1

2}

Affiliations

¹ Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Muang, Phitsanulok, Thailand.
² Centre of Excellence in Medical Biotechnology, Faculty of Medical Science, Naresuan University, Muang, Phitsanulok, Thailand.

Abstract

Acinetobacter baumannii is a major cause of nosocomial infection, and the incidence of extensively drug-resistant A. baumannii (XDRAB) infections has dramatically increased worldwide. In this study, we aimed to explore the complete genome sequence of XDRAB 329, ST1166/98 (Oxford/Pasteur), which is an outbreak clone from a hospital in Thailand. Whole-genome sequencing (WGS) was performed using short-read Illumina and long-read PacBio sequencing, and a conjugation assay of its plasmid was performed. The complete genome sequence of A. baumannii AB329 revealed a circular chromosome 3,948,038 bp in length with 39% GC content. Antibiotic resistance genes (ARGs), including beta-lactam resistance (bla _OXA-51, bla _ADC-25, bla _OXA-23, bla _TEM-1D), aminoglycoside resistance (aph(3')-Ia, aph(3″)-Ib, aph(6)-Id, armA), tetracycline resistance (tet(B), tet (R)), macrolide resistance (mph(E), msr(E)), and efflux pumps, were found. Mobile genetic elements (MGEs) analysis of A. baumannii AB329 revealed two plasmids (pAB329a and pAB329b), three prophages, 19 genomic islands (GIs), and 33 insertion sequences (ISs). pAB329a is a small circular plasmid of 8,731 bp, and pAB329b is a megaplasmid of 82,120 bp. aph(3')-VIa was detected in pAB329b, and a major facilitator superfamily (MFS) transporter was detected in the prophage. Acinetobacter baumannii resistance island 4 (AbaR4) harboring tetracycline and aminoglycoside resistance was detected in the genome of A. baumannii AB329. pAB329b, which belongs to Rep-type GR6 (plasmid lineage LN_1), is a conjugative plasmid with the ability to transfer an aminoglycoside resistance gene to sodium azide-resistant A. baumannii. This study provides insights into the features of the MGEs of XDRAB, which are the main reservoir and source of dissemination of ARGs.

Keywords: Aminoglycoside resistance; Antibiotic resistance genes; Conjugative plasmid; Extensively-drug resistant Acinetobacter baumannii; Gene transfer; Mobile genetic elements.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acinetobacter baumannii* / genetics
Aminoglycosides / pharmacology
Anti-Bacterial Agents* / pharmacology
DNA Transposable Elements
Drug Resistance, Bacterial
Macrolides
Plasmids / genetics

Substances

Anti-Bacterial Agents
Aminoglycosides
Macrolides
DNA Transposable Elements

Grants and funding

This work was supported by National Research Council of Thailand (NRCT) under the Mid-career Researcher grant (RSA6180042). Udomluk Leungtongkam was supported by The Royal Golden Jubilee Ph.D. Program (PHD/0227/2560). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.