1. Distribution of β-lactamase genes among carbapenem-resistant Klebsiella pneumoniae strains isolated from patients in Turkey.
- Author
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Iraz M, Özad Düzgün A, Sandallı C, Doymaz MZ, Akkoyunlu Y, Saral A, Peleg AY, Özgümüş OB, Beriş FŞ, Karaoğlu H, and Çopur Çiçek A
- Subjects
- Bacterial Proteins metabolism, DNA, Bacterial chemistry, DNA, Bacterial genetics, DNA, Bacterial metabolism, Drug Resistance, Bacterial, Genotype, Humans, Klebsiella Infections diagnosis, Klebsiella Infections microbiology, Klebsiella pneumoniae enzymology, Klebsiella pneumoniae isolation & purification, Microbial Sensitivity Tests, Polymerase Chain Reaction, Sequence Analysis, DNA, Turkey, beta-Lactamases metabolism, Anti-Bacterial Agents pharmacology, Bacterial Proteins genetics, Carbapenems pharmacology, Klebsiella pneumoniae drug effects, beta-Lactamases genetics
- Abstract
Background: The emergence of carbapenem-resistant Klebsiella pneumoniae poses a serious problem to antibiotic management. We investigated the β-lactamases in a group of carbapenem-resistant K. pneumoniae clinical isolates from Turkey., Methods: Thirty-seven strains of K. pneumoniae isolated from various clinical specimens were analyzed by antimicrobial susceptibility testing, PCR for the detection of β-lactamase genes, DNA sequencing, and repetitive extragenic palindronic (REP)-PCR analysis., Results: All 37 isolates were resistant to ampicillin, ampicillin/sulbactam, piperacillin, piperacillin/tazobactam, ceftazidime, cefoperazone/sulbactam, cefepime, imipenem, and meropenem. The lowest resistance rates were observed for colistin (2.7%), tigecycline (11%), and amikacin (19%). According to PCR and sequencing results, 98% (36/37) of strains carried at least one carbapenemase gene, with 32 (86%) carrying OXA-48 and 7 (19%) carrying NDM-1. No other carbapenemase genes were identified. All strains carried a CTX-M-2-like β-lactamase, and some carried SHV- (97%), TEM- (9%), and CTX-M-1-like (62%) β-lactamases. Sequence analysis of bla(TEM) genes identified a bla(TEM-166) with an amino acid change at position 53 (Arg53Gly) from bla(TEM-1b), the first report of a mutation in this region. REP-PCR analysis revealed that there were seven different clonal groups, and temporo-spatial links were identified within these groups., Conclusions: Combinations of β-lactamases were found in all strains, with the most common being OXA-48, SHV, TEM, and CTX-M-type (76% of strains). We have reported, for the first time, a high prevalence of the NDM-1 (19%) carbapenemase in carbapenem-resistant K. pneumoniae from Turkey. These enzymes often co-exist with other β-lactamases, such as TEM, SHV, and CTX-M β-lactamases.
- Published
- 2015
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