title: Occurrence of plasmidic AmpC type beta-lactamase-mediated resistance in Escherichia coli: report from the SENTRY Antimicrobial Surveillance Program (North America, 2004).
abstract: Among 1429 Escherichia coli isolates collected as part of the SENTRY Antimicrobial Surveillance Program (2004) from 30 North American medical centres, 65 (4.5%) were screen-positive for an extended-spectrum beta-lactamase (ESBL). Among the strains with a negative ESBL confirmatory test (n=26; clavulanic acid inhibition), a CMY-2 enzyme was detected in 13 isolates (50.0%), FOX-5 in 3 isolates (11.5%) and DHA-1 in 1 isolate (3.8%). These AmpC-producing E. coli were cephamycin (cefoxitin)-resistant but susceptible to cefepime (minimum inhibitory concentration (MIC) < OR =0.12-4 mg/L). Clearly, the ESBL tests recommended by the Clinical and Laboratory Standards Institute identify only a fraction of E. coli with elevated beta-lactam MIC values as ESBL-producing strains; the majority of the remaining strains would be potentially responsive to some other beta-lactams, directed by accurately performed and interpreted susceptibility methods.
authors.affiliation: JMI Laboratories, 345 Beaver Kreek Centre, Suite A, North Liberty, IA 52317, USA. gauri-deshpande@jmilabs.com
authors.forename: Lalitagauri M
authors.initials: LM
authors.lastname: Deshpande
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Fritsche
authors.forename: Helio S
authors.initials: HS
authors.lastname: Sader
mesh_terms: D000046:Academic Medical Centers; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D009656:North America; D010957:Plasmids / Q000235:genetics*; D011159:Population Surveillance; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D047090:beta-Lactams; C103022:beta-lactamase CMY-2; C048795:AmpC beta-lactamases; D001618:beta-Lactamases