Extended-spectrum beta-lactamases in ceftazidime-resistant Escherichia coli and Klebsiella pneumoniae isolates in Turkish hospitals.
OBJECTIVE
To study the prevalence of TEM-, SHV- and GES-type beta -lactamases among Escherichia coli and Klebsiella pneumoniae strains having ceftazidime MICs higher than 2 mg/L.


METHODS
A total of 63 E. coli and 41 K. pneumoniae isolated from five different university hospitals were studied for the existence of TEM-, SHV- and GES-type beta -lactamases. Susceptibility tests were carried out according to the criteria of National Committee for Clinical Laboratory Standards. MICs were obtained by agar dilution method. Existence of extended-spectrum beta -lactamases (ESBLs) were assessed by double-disc synergy test (DDST). Existence of the above-mentioned beta -lactamase genes were studied both by PCR with specific oligonucleotide primers and isoelectric focusing methods.


RESULTS
None of the isolates were carbapenem-resistant. DDSTs were positive in 50 (79.3%) and 33 (80.5%) of E. coli and K. pneumoniae , respectively. TEM gene was detected in 41 (65.1%) and 19 (46.3%), whereas SHV gene in 18 (28.6%) and 20 (48.8%) of E. coli and K. pneumoniae strains, respectively. GES genes were not detected.


CONCLUSIONS
TEM and SHV genes are highly prevalent among ESBL-producing E. coli and K. pneumoniae , whereas GES-type ESBLs are absent and found not to be responsible of ceftazidime resistance in Turkish hospitals.
Hoşoğlu
S
S
Department of Infectious Diseases and Clinical Microbiology, Dicle University Hospital, Diyarbakir, Turkey. hosoglu@hotmail.com
Gündes
S
S
Kolayli
F
F
Karadenizli
A
A
Demirdağ
K
K
Günaydin
M
M
Altindis
M
M
Caylan
R
R
Ucmak
H
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D015780:Carbapenems / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology; D006761:Hospitals; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D014421:Turkey; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D002442:Ceftazidime; D001618:beta-Lactamases