High rate of detection of OXA-23-producing Acinetobacter from two general hospitals in Brazil

Abstract

Introduction: In recent decades, the prevalence of carbapenem-resistant Acinetobacter isolates has increased, and the production of oxacillinase (OXA)-type carbapenemases is the main mechanism underlying resistance. We evaluated OXA production from 114 Acinetobacter isolates collected between March and December 2013 from different clinical specimens of patients in two hospitals (Hospital 1 [n = 61] and Hospital 2 [n = 53]) located in Niterói, Rio de Janeiro, Brazil. We also evaluated the genetic diversity of OXA-producing isolates. Methods: All the isolates were identified through the automated system Vitek II and matrix-assisted laser desorption ionization-time of flight mass spectrometry MALDI-TOF MS as belonging to the A. baumannii-A. calcoaceticus complex. Antimicrobial susceptibility profiles were verified through agar diffusion tests. The presence of OXA-encoding genes was confirmed by PCR. The genetic diversity of isolates positive for carbapenemase production was analyzed through pulsed-field gel electrophoresis. Results: There was a high rate of resistance to carbapenems in the isolates (imipenem: 96%; meropenem: 92%) from both hospitals. Moreover, a high percentage (95.6%) of OXA-23-positive isolates was observed for both hospitals, indicating that this was the main mechanism of carbapenem-resistance among the studied population. In addition, most isolates (96.5%) were positive for bla OXA-51 . A high genetic diversity and a few major genotypes were found among the OXA-23-positive isolates analyzed. Only intra-hospital dissemination was observed. Conclusions: The elevated dissemination of bla OXA-23-like observed among Acinetobacter isolates from both the studied hospitals highlights the need for continuous epidemiological surveillance in these institutions.

Acinetobacter baumannii Infections in Times of COVID-19 Pandemic

“…Among carbapenemases, Class D beta-lactamases—also called oxacillinases (OXAs)—are more frequent. Currently, the main groups of OXA-type carbapenemases identified in A. baumannii are OXA-23-like, OXA-24/40-like, OXA-58-like, OXA-143-like, and OXA-235-like groups, and the intrinsic chromosomal OXA-51-like group [ 90 ]. Acquired resistance to aminoglycosides (plasmid-borne aminoglycosides-modifying enzymes and 16S rRNA methylases) and fluoroquinolones (mutations in gyrA and/or parC) have been described in carbapenemase-producing A. baumannii strains [ 91 ].…”

Carbapenamase-Producing Acinetobacter baumannii in China, Latin America and the Caribbean: A Systematic Review and Meta-Analysis

“…[45,54,55] Peer Reviewed used as expected prevalence in calculating sample size, as carbapenemase production is the CRAB's dominant cause. Considering three studies on molecular isolate typing in hospitals, [14][15][16] the confi dence level equal to 95% and precision equal to 5%, the estimated minimum CRAB sample size was 73. Consequently, we excluded 14 articles due to small sample size.…”

Genetic Diversity of OXA Producing Carbapenem-Resistant Acinetobacter baumannii from Environment of Tertiary Hospitals in Central Iran

“…In different regions of Iran, OXA type β-lactamases have been widely studied in clinical isolates of A. baumannii (17,28,29) and it has been shown that bla OXA-23 is the most frequent OTC gene among nosocomial A. baumannii isolates (17,(30)(31)(32)(33). However, data on the distribution of bla OXA-23 in the environmental isolates of A. baumannii is uncommon.…”