Epidemiological Characterizations of Class 1 Integrons from Multidrug-Resistant Acinetobacter Isolates in Daejeon, Korea

• Published in: Annals of laboratory medicine Vol. 34; no. 4; pp. 293 - 299
• Main Authors: Sung, Ji Youn, Koo, Sun Hoe, Kim, Semi, Kwon, Kye Chul
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Society for Laboratory Medicine 01.07.2014; 대한진단검사의학회
• Subjects: Acinetobacter - drug effects; Acinetobacter - isolation & purification; Acinetobacter - metabolism; Acinetobacter baumannii - drug effects; Acinetobacter baumannii - isolation & purification; Acinetobacter baumannii - metabolism; Acinetobacter Infections - epidemiology; Acinetobacter Infections - microbiology; Anti-Bacterial Agents - pharmacology; DNA, Bacterial - chemistry; DNA, Bacterial - metabolism; Drug Resistance, Multiple, Bacterial; Humans; Integrons - genetics; Microbial Sensitivity Tests; Multilocus Sequence Typing; Original; Polymerase Chain Reaction; Republic of Korea; 병리학; Republic of Korea; Sequence types; MDR Acinetobacter spp; MLST; Integron
• ISSN: 2234-3806; 2234-3814; 2234-3814
• DOI: 10.3343/alm.2014.34.4.293

Multidrug-resistant (MDR) Acinetobacter spp. acquire antimicrobial agent-resistance genes via class 1 integrons. In this study, integrons were characterized to investigate the antimicrobial resistance mechanisms of MDR Acinetobacter isolates. In addition, the relationship between the integron type and integron-harboring bacterial species was analyzed by using epidemiological typing methods. Fifty-six MDR Acinetobacter spp.-A. baumannii (N=30), A. bereziniae (N=4), A. nosocomialis (N=5), and A. pittii (N=17)-were isolated. The minimum inhibitory concentrations (MICs) were determined on the basis of the results of the Epsilometer test (Etest). PCR and DNA sequencing was performed to characterize the gene cassette arrays of class 1 integrons. Multilocus sequence typing (MLST) and repetitive extragenic palindromic sequence (REP)-PCR were performed for epidemiological typing. Class 1 integrons were detected in 50 (89.3%) of the 56 isolates, but no class 2 or 3 integron was found within the cohorts. The class 1 integrons were classified into 4 types: 2.3-kb type A (aacA4-catB8-aadA1), 3.0-kb type B (aacA4-blaI MP-1 -bla OXA-2), 3.0-kb type C (bla VIM-2-aacA7-aadA1), and 1.8-kb type D (aac3-1-bla OXA-2 -orfD). Type A was most prevalent and was detected only in A. baumannii isolates, except for one A. bereziniae isolate; however, type B was amplified in all Acinetobacter isolates except for A. baumannii isolates, regardless of clone and separation time of the bacteria. Although class 1 integron can be transferred horizontally between unrelated isolates belonging to different species, certain types of class 1 integrons tend to transfer horizontally and vertically among A. baumannii or non-baumannii Acinetobacter isolates.