A comparative study of class 1 integrons in Acinetobacter baumannii.
Multidrug resistance (MDR) in Acinetobacter baumannii is increasingly reported and has become a significant public concern. The method responsible for the acquisition of resistance genes via integrons from the environment or intra-species in A. baumannii remains to be understood. This study was performed to investigate the transmission route of these integrons using a comparative analysis of published A. baumannii complete genomes. The phylogenetic analysis of A. baumannii type 1 integrases (IntI1) showed that the integrons could be transferred across the two evolutionary lineages, the international clone I (IC I) and clone II (IC II) strains. In addition, the integrons in A. baumannii strains were mainly responsible for the transfer of resistance genes for two types of long-term usage antibiotics and antiseptics, such as aminoglycosides, chloramphenicol and the quaternary-ammonium-compound family. The in silico comparative analysis of known integron integrases revealed that the intI genes were phylogenetically related among A. baumannii strains and some microorganisms living in a sediment community, implicating that the integrons of A. baumannii might have originated from those microorganisms belonging to the β-preoteobacterial class in the sediment environment. The data suggest that the gain of class 1 integrons in A. baumannii strains may have started before the antibiotic era. This report shows that the origins of A. baumannii class 1 integrons may be the soil environment and that the resistance genes included in integrons are horizontally transferred across all the A. baumannii genomes, including IC I and IC II.
Department of Bioinformatics, Chung Hua University, Hsin-Chu City, Taiwan; Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan.
Chih-Chin
CC
Liu
Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan; Department of Computer Science, National Tsing Hua University, Hsin-Chu City, Taiwan.
Chuan Yi
CY
Tang
Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien City, Taiwan; Department of Laboratory Medicine, Buddhst Tzu Chi General Hospital, Hualien City, Taiwan.
Kai-Chih
KC
Chang
Department of Medicine, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu City, Taiwan; School of Medicine, National Taiwan University, Taipei City, Taiwan.
Han-Yueh
HY
Kuo
Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan; Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsin-Chu City, Taiwan. Electronic address: d918229@gmail.com.
Ming-Li
ML
Liou
D040981:Acinetobacter baumannii / Q000235:genetics*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000235:genetics; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics; D004269:DNA, Bacterial / Q000145:classification / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial / Q000235:genetics; D023281:Genomics / Q000379:methods; D019426:Integrases / Q000145:classification / Q000235:genetics; D032023:Integrons / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D019426:Integrases
Acinetobacter baumannii; Integrase; Integron