title: Persistence of Multidrug-Resistant Acinetobacter baumannii Isolates Harboring blaOXA-23 and bap for 5 Years.
abstract: The emergence and dissemination of carbapenemase-producing Acinetobacter baumannii isolates have been reported worldwide, and A. baumannii isolates harboring blaOXA-23 are often resistant to various antimicrobial agents. Antimicrobial resistance can be particularly strong for biofilm-forming A. baumannii isolates. We investigated the genetic basis for carbapenem resistance and biofilm-forming ability of multidrug-resistant (MDR) clinical isolates. Ninety-two MDR A. baumannii isolates were collected from one university hospital located in the Chungcheong area of Korea over a 5-year period. Multiplex PCR and DNA sequencing were performed to characterize carbapenemase and bap genes. Clonal characteristics were analyzed using REP-PCR. In addition, imaging and quantification of biofilms were performed using a crystal violet assay. All 92 MDR A. baumannii isolates involved in our study contained the blaOXA-23 and bap genes. The average absorbance of biomass in Bap-producing strains was much greater than that in non-Bap-producing strains. In our study, only three REP-PCR types were found, and the isolates showing type A or type B were found more than 60 times among unique patients during the 5 years of surveillance. These results suggest that the isolates have persisted and colonized for 5 years, and biofilm formation ability has been responsible for their persistence and colonization.
authors.affiliation: Department of Biomedical Laboratory Science, Far East University, Eumseong 27601, Republic of Korea.
authors.forename: Ji Youn
authors.initials: JY
authors.lastname: Sung
authors.affiliation: Department of Laboratory Medicine, College of Medicine, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Sun Hoe
authors.initials: SH
authors.lastname: Koo
authors.affiliation: Department of Laboratory Medicine, College of Medicine, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Semi
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine, College of Medicine, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Gye Cheol
authors.initials: GC
authors.lastname: Kwon
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D015780:Carbapenems; D024901:Drug Resistance, Multiple, Bacterial; D005798:Genes, Bacterial; D005840:Gentian Violet; D006801:Humans; D060885:Multiplex Polymerase Chain Reaction; D056910:Republic of Korea / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D013997:Time Factors; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D001618:beta-Lactamases; C000599728:beta-lactamase OXA-23, Acinetobacter baumannii; C063912:carbapenemase; D005840:Gentian Violet
keywords: Acinetobacter baumannii; Carbapenemase; antimicrobial resistance; biofilm; crystal violet assay