Distribution of β-lactamase genes among carbapenem-resistant Klebsiella pneumoniae strains isolated from patients in Turkey.
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.
Department of Medical Microbiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Meryem
M
Iraz
Department of Genetic and Bioengineering, Faculty of Engineering and Natural Sciences, Gumushane University, Gumushane, Turkey.
Azer
A
Özad Düzgün
Department of Biology, Faculty of Arts & Sciences, Recep Tayyip Erdoğan University, Rize, Turkey.
Cemal
C
Sandallı
Department of Medical Microbiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Mehmet Ziya
MZ
Doymaz
Department of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Yasemin
Y
Akkoyunlu
Department of Biology, Faculty of Arts & Sciences, ArtvinCoruh University, Artvin, Turkey.
Ayşegül
A
Saral
Department of Microbiology, Monash University, Melbourne, Australia.|Department of Infectious Diseases, The Alfred Hospital, Melbourne, Australia.
Anton Y
AY
Peleg
Department of Microbiology, Faculty of Medicine, Recep Tayyip Erdoğan University, Rize, Turkey.
Osman Birol
OB
Özgümüş
Department of Biology, Faculty of Arts & Sciences, Recep Tayyip Erdoğan University, Rize, Turkey.
Fatih Şaban
FŞ
Beriş
Department of Aquaculture, Faculty of Fisheries, Recep Tayyip Erdoğan University, Rize, Turkey.
Hakan
H
Karaoğlu
Department of Microbiology, Faculty of Medicine, Recep Tayyip Erdoğan University, Rize, Turkey. aysegul.copur@erdogan.edu.tr.
Ayşegül
A
Çopur Çiçek
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D005838:Genotype; D006801:Humans; D007710:Klebsiella Infections / Q000175:diagnosis / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014421:Turkey; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases
Colistin; K. pneumoniae; NDM-1; OXA-48; bla(TEM-166)