Dissemination of CTX-M-3 and CMY-2 beta-lactamases among clinical isolates of Escherichia coli in southern Taiwan.
A total of 1,210 clinical isolates of Escherichia coli collected from a university hospital in southern Taiwan were screened for production of extended-spectrum beta-lactamases (ESBLs). Expression of classical ESBLs (resistant to extended-spectrum beta-lactam agents and susceptible to beta-lactam inhibitors) was inferred in 18 isolates by the phenotypic confirmatory test. These included 10 isolates producing CTX-M-3, 2 strains carrying SHV-12, 1 strain harboring SHV-5, 1 strain expressing TEM-10, and 4 strains producing unidentifiable ESBLs with a pI of 8.05, 8.0, or 7.4. Eighteen isolates that showed decreased susceptibilities to ceftazidime and/or cefotaxime, negative results for the confirmatory test, and high-level resistance to cefoxitin (MICs of >/=128 microg/ml) were also investigated. Five isolates were found to produce CMY-2 AmpC enzymes, one isolate carried both CTX-M-3 and CMY-2, and the remaining three and nine isolates expressed putative AmpC beta-lactamases with pIs of >9.0 and 8.9, respectively. Thus, together with the isolate producing CTX-M-3 and CMY-2, 19 (1.6%) isolates produced classical ESBLs. Pulsed-field gel electrophoresis revealed that all isolates carrying CTX-M-3 and/or CMY-2 were genetically unrelated, indicating that dissemination of resistance plasmids was responsible for the spread of these two enzymes among E. coli in this area. Among the 16 isolates expressing CTX-M-3 and/or CMY-2, 5 might have colonized outside the hospital environment. Our data indicate that CTX-M-3 and CMY-2, two beta-lactamases initially identified in Europe, have been disseminated to and are prevalent in Taiwan.
Yan
J J
JJ
Departments of Pathology, National Cheng Kung University Medical Center, Tainan, Taiwan.
Ko
W C
WC
Tsai
S H
SH
Wu
H M
HM
Jin
Y T
YT
Wu
J J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002675:Child, Preschool; D003428:Cross Infection / Q000382:microbiology; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D029968:Escherichia coli Proteins; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011815:R Factors; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D029968:Escherichia coli Proteins; C103022:beta-lactamase CMY-2; D001618:beta-Lactamases; C000605810:beta-lactamase CMY-2, E coli