Molecular Epidemiology of Emerging Carbapenem Resistance in Acinetobacter nosocomialis and Acinetobacter pittii in Taiwan, 2010 to 2014

Abstract

This study investigated the molecular epidemiology of carbapenem-resistant Acinetobacter nosocomialis and Acinetobacter pittii (ANAP). Clinical isolates of Acinetobacter spp. collected by the biennial nationwide Taiwan Surveillance of Antimicrobial Resistance program from 2010 to 2014 were subjected to species identification, antimicrobial susceptibility testing, and PCR for detection of carbapenemase genes. Whole-genome sequencing or PCR mapping was performed to study the genetic surroundings of the carbapenemase genes. Among 1,041 Acinetobacter isolates, the proportion of ANAP increased from 11% in 2010 to 22% in 2014. The rate of carbapenem resistance in these isolates increased from 7.5% (3/40) to 22% (14/64), with a concomitant increase in their resistance to other antibiotics. The blaOXA-72 and blaOXA-58 genes were highly prevalent in carbapenem-resistant ANAP. Various genetic structures were found upstream of blaOXA-58 in different plasmids. Among the plasmids found to contain blaOXA-72 flanked by XerC/XerD, pAB-NCGM253-like was identified in 8 of 10 isolates. Conjugations of plasmids carrying blaOXA-72 or blaOXA-58 to A. baumannii were successful. In addition, three isolates with chromosome-located blaOXA-23 embedded in AbGRI1-type structure with disruption of genes other than comM were detected. Two highly similar plasmids carrying class I integron containing blaIMP-1 and aminoglycoside resistance genes were also found. The universal presence of blaOXA-272/213-like on A. pittii chromosomes and their lack of contribution to carbapenem resistance indicate its potential to be a marker for species identification. The increase of ANAP, along with their diverse mechanisms of carbapenem resistance, may herald their further spread and warrants close monitoring.

Phenotypic Variation and Carbapenem Resistance Potential in OXA-499-Producing Acinetobacter pittii

“…It is known that the accumulation of one or more single-nucleotide variants (SNVs) in genes encoding antibiotic targets or transposon insertions can lead to antibiotic resistance (Schurch and van Schaik, 2017). Published carbapenem resistance-related mechanisms in A. pittii include plasmid-borne bla OXA−23 , bla OXA−72 , or bla OXA−58 ; AbaR4located bla OXA−23 on the chromosome; plasmid-borne class I integron containing bla IMP−1 (Montealegre et al, 2012;Silva et al, 2018;Chen et al, 2019); and a composite transposon containing bla NDM−1 (Yang et al, 2012). In addition, it has been proposed that A. pittii may be a resistance reservoir for the dissemination of NDM-1 (Bogaerts et al, 2013;Huang et al, 2015).…”

“…The rate of carbapenem resistance in A. nosocomialis and A. pittii isolates increased from 7.5% in 2010 to 22% in 2014 (Chen et al, 2019). Carbapenem resistance in A. pittii is mainly associated with the production of the carbapenem-hydrolyzing class D β-lactamases (CHDLs), such as OXA-23, OXA-58, OXA-72, OXA-143, and their variants (Zander et al, 2014a;D'Souza et al, 2017;Singkham-In and Chatsuwan, 2018;Chen et al, 2019). Besides, NDM-1-producing A. pittii isolates have also been reported in several cases (Yang et al, 2012;Hammerum et al, 2015;Pailhories et al, 2017;Deglmann et al, 2019).…”

“…Among these species, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals globally (Weber et al, 2015). In the last few decades, relatively few studies have investigated non-baumannii Acinetobacter spp., likely owing to their low prevalence and resistant rates (Chen et al, 2019). However, non-baumannii Acinetobacter spp.…”

“…The emergence of carbapenem-resistant A. pittii has been reported worldwide. The rate of carbapenem resistance in A. nosocomialis and A. pittii isolates increased from 7.5% in 2010 to 22% in 2014 (Chen et al, 2019). Carbapenem resistance in A. pittii is mainly associated with the production of the carbapenem-hydrolyzing class D β-lactamases (CHDLs), such as OXA-23, OXA-58, OXA-72, OXA-143, and their variants (Zander et al, 2014a;D'Souza et al, 2017;Singkham-In and Chatsuwan, 2018;Chen et al, 2019).…”

AdeABC Efflux Pump Controlled by AdeRS Two Component System Conferring Resistance to Tigecycline, Omadacycline and Eravacycline in Clinical Carbapenem Resistant Acinetobacter nosocomialis

“…Acinetobacter nosocomialis is an emerging opportunistic pathogen that is usually grouped into the Acinetobacter calcoaceticus-baumannii complex (Acb complex) (Vijayakumar et al, 2019). In Asia, the carbapenem resistant rate among infections caused by A. nosocomialis is as high as 30% (Chen et al, 2018;Singkham-In and Chatsuwan, 2018;Chen et al, 2019). Tigecycline has been regarded as one of the final armamentaria against carbapenem resistant A. nosocomialis (CRAn).…”