Clinical features and molecular epidemiology of CMY-type beta-lactamase-producing Escherichia coli.
BACKGROUND
Knowledge of the clinical features of infections caused by Escherichia coli strains that produce plasmid-mediated AmpC beta-lactamase is limited. Of the several groups of plasmid-mediated AmpC beta-lactamases, CMY-type beta-lactamase is the most common in the United States.


METHODS
We prospectively identified patients infected or colonized with E. coli strains that produce CMY-type beta-lactamase, and we collected clinical data over a 7-month period. A retrospective cohort study was performed to identify features associated with these cases. Patients with extended-spectrum beta-lactamase-producing E. coli were used as a control group. Pulsed-field gel electrophoresis, plasmid analysis, and phylogenetic typing were performed.


RESULTS
Twenty-two patients with infection or colonization due to CMY-type beta-lactamase-producing E. coli and 25 patients with infection or colonization due to extended-spectrum beta-lactamase-producing E. coli were identified. The demographic characteristics of the patients were similar in both cohorts. Patients with CMY-type beta-lactamase-producing E. coli were significantly more likely to have symptomatic infection than were patients with extended-spectrum beta-lactamase-producing E. coli (P = .028). The CMY-type beta-lactamase was identified as CMY-2 or its variants. Ninety-four percent of the CMY-type beta-lactamase-producing isolates belonged to E. coli phylogenetic groups B2 and D, which are associated with virulence. Many of the isolates shared similar plasmid profiles, whereas the pulsed-field gel electrophoresis profiles were diverse. Co-resistance to non-beta-lactam antimicrobials was common.


CONCLUSIONS
In Pittsburgh, Pennsylvania, CMY-type beta-lactamase-producing E. coli strains are almost as common as extended-spectrum beta-lactamase-producing E. coli strains, and they cause symptomatic infection in the majority of cases.
Sidjabat
Hanna E
HE
Division of Infectious Diseases, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15261, USA.
Paterson
David L
DL
Qureshi
Zubair A
ZA
Adams-Haduch
Jennifer M
JM
O'Keefe
Alexandra
A
Pascual
Alvaro
A
Rodríguez-Baño
Jesús
J
Doi
Yohei
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010802:Phylogeny; D010957:Plasmids / Q000032:analysis; D014481:United States; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D001618:beta-Lactamases