Comparative study of different molecular methods for typing of Acinetobacter baumannii clinical isolates from University Hospitals
- 289 Downloads
Acinetobacter baumannii, a rod-shape Gram-negative bacterium, is an opportunistic pathogen causing diseases in humans. This bacterium has been recognized as one of the leading causes of nosocomial infection which occurs in hospital or hospital-like setting. The antibiotic resistance of A. baumannii could result from the heavy use of antibiotics and has been recognized as a threat to human health. However, prevention against the disease caused by A. baumannii is difficult due to variable host susceptibility against their infections. We isolated 53 bacterial strains from four different university hospitals in South Korea and identified 34 out of the 53 isolates as A. baumannii, based on the nucleotide sequence of 16S rRNA and gpi genes. For the subtyping of the clinical isolates, we used enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and multilocus sequencing typing (MLST) and compared the results. The result of ERIC-PCR showed that there are 14 distinct DNA fingerprint patterns in the 34 A. baumannii clinical isolates. For MLST analysis of the isolates, we amplified and sequenced seven housekeeping genes (gltA, gyrB, gdhB, recA, cpn60, gpi, and rpoD) from each isolate. Each unique allelic profile at the concatenated nucleotide sequences of the seven genes was assigned as a sequence type (ST) and six different STs (ST92, ST105, ST138, ST169, ST262, and ST357) were detected in the 34 A. baumannii clinical isolates. Among the six STs, ST138 was the most ubiquitous in the A. baumannii clinical isolates. To examine the regional distribution of the isolates, STs were clustered into clonal complexes based on their similarity to a previously registered central genotype and the clustering was verified by network phylogenetic analysis.
KeywordsAcinetobacter baumannii Multilocus sequencing typing Epidemiology
The present work was conducted with funding from the Research Fund of Dankook University in 2012.
Conflict of interest
The authors declare no conflict of interest.
- de Bruijn FJ (1992) Use of repetitive (repetitive extragenic palindromic and enterobacterial repetitive intergeneric consensus) sequences and the polymerase chain reaction to fingerprint the genomes of Rhizobium meliloti isolates and other soil bacteria. Appl Environ Microbiol 58:2180–2187PubMedCentralPubMedGoogle Scholar
- Lockhart SR, Abramson MA, Beekmann SE, Gallagher G, Riedel S, Diekema DJ, Quinn JP, Doern GV (2007) Antimicrobial resistance among Gram-negative bacilli causing infections in intensive care unit patients in the United States between 1993 and 2004. J Clin Microbiol 45:3352–3359PubMedCentralCrossRefPubMedGoogle Scholar
- Maiden MC, Bygraves JA, Feil E, Morelli G, Russell JE, Urwin R, Zhang Q, Zhou J, Zurth K, Caugant DA et al (1998) Multilocus sequence typing: a portable approach to the identification of clones within populations of pathogenic microorganisms. Proc Natl Acad Sci USA 95:3140–3145PubMedCentralCrossRefPubMedGoogle Scholar
- Rivera IG, Chowdhury MA, Huq A, Jacobs D, Martins MT, Colwell RR (1995) Enterobacterial repetitive intergenic consensus sequences and the PCR to generate fingerprints of genomic DNAs from Vibrio cholerae O1, O139, and non-O1 strains. Appl Environ Microbiol 61:2898–2904PubMedCentralPubMedGoogle Scholar
- Wilks M, Wilson A, Warwick S, Price E, Kennedy D, Ely A, Millar MR (2006) Control of an outbreak of multidrug-resistant Acinetobacter baumannii–calcoaceticus colonization and infection in an intensive care unit (ICU) without closing the ICU or placing patients in isolation. Infect Control Hosp Epidemiol 27:654–658CrossRefPubMedGoogle Scholar