Differences in phenotypic and genotypic traits against antimicrobial agents between Acinetobacter baumannii and Acinetobacter genomic species 13TU.
OBJECTIVE
To investigate the differences in antimicrobial susceptibility and resistance mechanisms against imipenem between Acinetobacter baumannii and Acinetobacter genomic species 13TU.


METHODS
A total of 232 non-duplicate Acinetobacter species were consecutively collected from two Korean hospitals in Daegu, Republic of Korea, between November 2004 and November 2005. Antimicrobial susceptibility was determined by agar dilution methods. Resistance to imipenem was characterized by a carbapenemase activity test and PCR amplification. PFGE was performed to determine the clonal relatedness of imipenem-resistant Acinetobacter species.


RESULTS
A. baumannii was the most prevalent species (61.2%), followed by Acinetobacter genomic species 13TU (25.9%). The resistance rates of A. baumannii to most antimicrobial agents were higher than those of other Acinetobacter species, while the resistance rate to imipenem was the highest in Acinetobacter genomic species 13TU. Imipenem-resistant Acinetobacter genomic species 13TU isolates produced VIM-2 metallo-beta-lactamase, while imipenem-resistant A. baumannii isolates produced OXA-23 and/or OXA-51 beta-lactamase. Imipenem-resistant Acinetobacter strains originated from different clones in each hospital.


CONCLUSIONS
Two prevalent Acinetobacter species, A. baumannii and Acinetobacter genomic species 13TU, possess distinct phenotypic and genotypic traits against antimicrobials.
Lee
Jung Hoon
JH
Department of Microbiology, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea.
Choi
Chul Hee
CH
Kang
Hee Young
HY
Lee
Ji Young
JY
Kim
Jungmin
J
Lee
Yoo Chul
YC
Seol
Sung Yong
SY
Cho
Dong Taek
DT
Kim
Kun Woo
KW
Song
Do Young
DY
Lee
Je Chul
JC
D000150:Acinetobacter / Q000187:drug effects* / Q000235:genetics*; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism; D015780:Carbapenems / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D016680:Genome, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001618:beta-Lactamases / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D015378:Imipenem; D001618:beta-Lactamases; C063912:carbapenemase