Molecular epidemiology of carbapenem non-susceptible Acinetobacter nosocomialis in a medical center in Taiwan

Ya-Sung Yang; Yi-Tzu Lee; Yung-Chih Wang; Chun-Hsiang Chiu; Shu-Chen Kuo; Jun-Ren Sun; Ti Yin; Te-Li Chen; Jung-Chung Lin; Chang-Phone Fung; Feng-Yee Chang

doi:10.1016/j.meegid.2015.02.017

Molecular epidemiology of carbapenem non-susceptible Acinetobacter nosocomialis in a medical center in Taiwan

Infect Genet Evol. 2015 Apr:31:305-11. doi: 10.1016/j.meegid.2015.02.017. Epub 2015 Feb 24.

Authors

Affiliations

¹ Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
² Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Emergency Department, Taipei Veterans General Hospital, Taipei, Taiwan.
³ Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
⁴ Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan.
⁵ Clinical Microbiology Laboratory Division of Clinical Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
⁶ Department of Nursing, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; School of Nursing, National Yang-Ming University, Taipei, Taiwan.
⁷ Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Division of Infectious Diseases, Cheng-Hsin General Hospital, Taipei, Taiwan. Electronic address: [email protected].
⁸ Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.

PMID: 25724091
DOI: 10.1016/j.meegid.2015.02.017

Abstract

The mechanism by which carbapenem non-susceptible Acinetobacter nosocomialis (CNSAN) is disseminated is rarely described in the literature. In this study, we delineated the molecular epidemiology of CNSAN isolated from patients in a medical center in Taiwan. Fifty-four non-duplicate bloodstream isolates of CNSAN were collected at the Taipei Veterans General Hospital between 2001 and 2007. Pulsed-field gel electrophoresis (PFGE) was performed to determine their clonal relationship. Carbapenem-resistance genes and associated genetic structures were detected by polymerase chain reaction (PCR) mapping. Southern hybridization was performed to determine the plasmid location of carbapenem-resistance genes. Transmissibility of these genes to Acinetobacterbaumannii was demonstrated by conjugation tests. The overall carbapenem non-susceptibility rate among A. nosocomialis isolates during the study period was 21.6% (54/250). PFGE revealed three major pulsotypes: H (n=23), I (n=10), and K (n=8). The most common carbapenem-resistance gene was blaOXA-58 (43/54, 79.6%), containing an upstream insertion sequence IS1006 and a truncated ISAba3 (IS1006-ΔISAba3-like-blaOXA-58). All isolates belonging to the pulsotypes H, I, and K carried plasmid located IS1006-ΔISAba3-like-blaOXA-58. A common plasmid carrying ISAba1-blaOXA-82 was found in six isolates, which belonged to five pulsotypes. A type 1 integron that carried blaIMP-1 was detected in different plasmids of seven isolates, which belonged to five pulsotypes. Plasmids carrying these carbapenem-resistant determinants were transmissible from A. nosocomialis to A. baumannii via conjugation. In this medical center, CNSAN mainly emerged through clonal dissemination; propagation of plasmids and integrons carrying carbapenem-resistant determinants played a minor role. This study showed that plasmids carrying carbapenem-resistant determinants are transmissible from A. nosocomialis to A. baumannii.

Keywords: Acinetobacter; Bacteremia; Carbapenem; Epidemiology; Outbreak; Resistance.

Publication types

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

MeSH terms

Acinetobacter / classification
Acinetobacter / drug effects*
Acinetobacter / genetics*
Acinetobacter / isolation & purification
Acinetobacter Infections / epidemiology*
Acinetobacter Infections / microbiology*
Carbapenems / pharmacology*
Conjugation, Genetic
Cross Infection*
Electrophoresis, Gel, Pulsed-Field
Genes, Bacterial
Humans
Microbial Sensitivity Tests
Molecular Epidemiology
Multilocus Sequence Typing
Phylogeny
Taiwan / epidemiology
beta-Lactam Resistance*

Substances

Carbapenems