Prevalence of PER-1 Extended-Spectrum beta-Lactamase-Producing Clinical Isolates of Acinetobacter baumannii in a University Hospital, Busan, Korea / 대한임상미생물학회지

ABSTRACT

BACKGROUND: In recent years, Acinetobacter baumannii isolates acquired resistance to cefepime have increased significantly. The aim of this study was to survey the prevalence of PER-1 extendedspectrum beta -lactamase (ESBL)-producing A. baumannii isolates in a University Hospital, Busan, Korea. METHODS: Antimicrobial susceptibilities were tested by the disk diffusion method, and double disk synergy test was performed for screening of ESBL-production. MICs were determined by agar dilution method. The isoelectric points of beta -lactamases were determined by isoelectric focusing. Transferability of cefepime-resistance were tested by conjugation. blaPER-1 and blaPER-2 alleles were detected by PCR, and the DNA sequences of amplified products were determined by using the dideoxy-chain termination method. RESULTS: Among 51 clinical isolates of A. baumannii intermediate or resistant to cefepime, 10 isolates (19.6%) showed positive results in double disk synergy test. PCR-based experiments detected blaPER-1 gene in all the 10 isolates. All the isolates contained three beta -lactamase bands pI 5.3, 7.9, and 9.4. MICs of ampicillin, piperacillin, cephalothin, cefoxitin, cefoperazone, ceftazidime, cefotaxime, cefepime, and aztreonam were >256 mg/L, respectively, and them of imipenem were 8-16 mg/L. CONCLUSION: The prevalence of PER-1-producing A. baumannii strains in Busan was less than that of in Seoul. But an outbreak of infection caused by this strain in an intensive care unit shows that spread of PER-1-producing A. baumannii strains can be anticipated in a near future. Prevention of hospital infection by these resistant microorganisms are needed.