Community emergence of CTX-M type extended-spectrum beta-lactamases among urinary Escherichia coli from women.
OBJECTIVE
To conduct a territory-wide study of extended-spectrum beta-lactamases (ESBLs) among community isolates of urinary Escherichia coli from women in Hong Kong.


METHODS
Up to 50 consecutive single-patient E. coli isolates, collected from 13 laboratories in 2004, were studied. The ESBLs were characterized by PCR sequencing using specific primers. The epidemiological relationship of the isolates was studied by PFGE and phylogenetic group PCRs.


RESULTS
Forty-two ESBL producers were found among 600 consecutive isolates tested. The ESBL prevalence was 7.3% (15/205) for women aged 18-35 years, 5% (11/219) for women aged 36-50 years, 6.3% (4/63) for women aged 51-64 years and 10.6% (12/113) for women aged >or=65 years (P=0.3). The ESBL-producing isolates were often multidrug-resistant and CTX-M-14 was found in 37 isolates, CTX-M-15 in 3 isolates and CTX-M-3 in 2 isolates. PFGE revealed no significant clusters among the ESBL producers. Overall, CTX-M-14 producers were significantly more likely to belong to group D than non-ESBL producers [18/37 (48.6%) versus 13/57 (22.8%), P=0.009]. However, 7 of 13 (53.8%) CTX-M-14 producers from women aged 18-35 years represented phylogenetic group B2, compared with 7 of 24 (29.2%) for women of all other ages (P=0.1).


CONCLUSIONS
The study documented the community emergence of CTX-M as the predominant ESBL type among urinary isolates from women. The spread of CTX-M enzymes among isolates from young women is concerning and deserves close monitoring.
Ho
P L
PL
Division of Infectious Diseases, Department of Microbiology and Centre of Infection, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, China. plho@hkucc.hku.hk
Poon
Winnie W N
WW
Loke
S L
SL
Leung
Marianne S T
MS
Chow
K H
KH
Wong
River C W
RC
Yip
K S
KS
Lai
Eileen L
EL
Tsang
Kenneth W T
KW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011159:Population Surveillance; D014552:Urinary Tract Infections / Q000453:epidemiology* / Q000382:microbiology; D014556:Urine / Q000382:microbiology; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C456080:beta-lactamase CTX-M-14; C473109:beta-lactamase CTX-M-15; C417271:beta-lactamase CTX-M-3; D001618:beta-Lactamases