Complete genome sequence of hypervirulent and outbreak-associated Acinetobacter baumannii strain LAC-4: epidemiology, resistance genetic determinants and potential virulence factors

• Published in: Scientific reports Vol. 5; no. 1; p. 8643
• Main Authors: Ou, Hong-Yu, Kuang, Shan N., He, Xinyi, Molgora, Brenda M., Ewing, Peter J., Deng, Zixin, Osby, Melanie, Chen, Wangxue, Xu, H. Howard
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02-03-2015; Nature Publishing Group
• Subjects: 45; 45/23; 45/77; 631/114/2785/2302; 631/208/212/748; 631/326/2521; 631/326/325/2482; Acinetobacter baumannii - classification; Acinetobacter baumannii - genetics; Acinetobacter baumannii - isolation & purification; Acinetobacter baumannii - pathogenicity; Acinetobacter Infections - epidemiology; Acinetobacter Infections - genetics; Acinetobacter Infections - microbiology; Antibiotic resistance; Antibiotics; Base Sequence; Chromosomes, Bacterial - genetics; Computer Simulation; Disease Outbreaks; DNA Transposable Elements - genetics; Drug resistance; Drug Resistance, Microbial - genetics; Drug Resistance, Multiple - genetics; Epidemiology; Genes; Genetic Loci; Genome, Bacterial; Genomes; Genomic islands; Genomic Islands - genetics; Genomics; Heme; Humanities and Social Sciences; Humans; Insertion; Insertion sequences; Los Angeles - epidemiology; Molecular Sequence Data; multidisciplinary; Multidrug resistance; Multilocus Sequence Typing; Mutagenesis, Insertional - genetics; Nucleotide sequence; Outbreaks; Oxygenase; Phylogeny; Polymerase Chain Reaction; Science; Sequence Analysis, DNA; Transposons; Virulence - genetics; Virulence factors; Virulence Factors - genetics; Los Angeles
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep08643

Acinetobacter baumannii
is an important human pathogen due to its multi-drug resistance. In this study, the genome of an ST10 outbreak
A. baumannii
isolate LAC-4 was completely sequenced to better understand its epidemiology, antibiotic resistance genetic determinants and potential virulence factors. Compared with 20 other complete genomes of
A. baumannii
, LAC-4 genome harbors at least 12 copies of five distinct insertion sequences. It contains 12 and 14 copies of two novel IS elements, IS
Aba25
and IS
Aba26
, respectively. Additionally, three novel composite transposons were identified: Tn
6250
, Tn
6251
and Tn
6252
, two of which contain resistance genes. The antibiotic resistance genetic determinants on the LAC-4 genome correlate well with observed antimicrobial susceptibility patterns. Moreover, twelve genomic islands (GI) were identified in LAC-4 genome. Among them, the 33.4-kb GI12 contains a large number of genes which constitute the K (capsule) locus. LAC-4 harbors several unique putative virulence factor loci. Furthermore, LAC-4 and all 19 other outbreak isolates were found to harbor a heme oxygenase gene (
hemO
)-containing gene cluster. The sequencing of the first complete genome of an ST10
A. baumannii
clinical strain should accelerate our understanding of the epidemiology, mechanisms of resistance and virulence of
A. baumannii
.