An unusual resistance phenotype in nosocomial strains of Enterococcus species in a Greek hospital
Abstract number: 1134_01_370
Metzidie E., Pournaras S., Sofianou D.
Enterococcus faecalis is a common nosocomial agent and usually demonstrates susceptibility to ampicillin, penicillin G and amoxicillin/clavulanicate, while Enterococcus faecium is commonly resistant to the above mentioned antimicrobial agents. The aim of our study is the presentation of an unusual resistance phenotype that was recently identified in a Greek tertiary hospital among A. faecalis and E. faecium, exhibiting resistance to penicillin and susceptibility to ampicillin and amoxicillin/clavulanate.
A total of 35 non-repetitive enterococcal strains were collected from various hospital infection samples. Identification and susceptibility testing were performed by using the Vitek 2 automated system (Biomerieux, Marcy l Etoile, France). The MICs for penicillin G, ampicillin and amoxicillin/clavulanic acid were determined using E-test. The production of beta-lactamase was evaluated using the cefinase test.
Among 35 isolates, 33 were identified as E. faecalis and 2 as E. faecium. All isolates were susceptible to ampicillin and amoxicillin/clavulanic acid with MIC ranging from 0.38 to 1.50 mg/L respectively but they were resistant to penicillin (MIC > 32 mg/L). Using the cefinase test they were found to be negative for beta-lactamase production. PFGE analysis revealed various unrelated clonal patterns.
A spread of this unusual resistance phenotype would affect the usefulness of penicillin that generally retains activity against E. faecalis. The aetiology of this phenotype is an object of study.
|Session name:||XXIst ISTH Congress|
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