In-vitro activity of FCE 22101 and other β-lactam antibiotics against enterobacteriaceae resistant to third, generation cephalosporins

V. Jarlier, M. H. Nicolas, A. Phillippon, A. M. Giroir, J. Grosset

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The in-vitro activity of FCE 22101 was compared with those of imipenem, aztreonam, cefotaxime, ceftriaxone and latamoxef against 223 Enterobacteriaceae (209 clinical isolates and 16 derivatives of Escherichia coli K12) chosen for their resistance (MIC ≥ 8 mg/l) to third-generation cephalosporins. The β-lactamases produced by the strains of Enterobacter cloacae, Klebsiella pneumoniae and Esch. coli were identified. The mean MICs of FCE 22101 were 2-8 mg/l for Ent. cloacae, Citrobacter freundii and Morganella morganii. For Ent. cloacae, the MICs were slightly higher for the cephalosporinase non overproducing (5·5-8 mg/l) than for the cephalosporinase overproducing (4·5 mg/l) strains. The mean MIC was 9 mg/l for Serratia spp. but for half of the strains the MICs were ≥ 16 mg/l. The MICs of FCE 22101 were 0·5-1 mg/l for the resistant clinical isolates or isogenic derivatives of K. pneumoniae and Esch. coli producing extended broad-spectrum β-lactamases (SHV-2, SHV-3 or CTX-1), whether measured in the presence of clavulanate or not, and against the sensitive controls. This showed that the compound was not affected by these new β-lactamases. The MICs of imipenem, on the average four to five times lower than those of FCE 22101, were found to be very similar for resistant and sensitive strains. The MICs of aztreonam were high (32-128 mg/l) for C.freundii, K. oxytoca and cephalosporinase overproducing strains of Ent. cloacae. There was cross-resistance between the third-generation cephalosporins, but the MICs of latamoxef remained low (1 mg/l) against M. morganii, Klebsiella spp. and Esch. coli.

Original languageEnglish (US)
Pages (from-to)165-172
Number of pages8
JournalJournal of Antimicrobial Chemotherapy
Issue number2
StatePublished - Aug 1989

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


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