EFfect of carbapenem administration on establishment of intestinal colonization by vancomycin-resistant enterococci and Klebsiella pneumoniae in mice

In a mouse model, ertapenem inhibited the anaerobic intestinal microflora and promoted overgrowth of enterococci, whereas imipenem-cilastatin had no effect on the indigenous microflora. Ertapenem, but not imipenem-cilastatin, promoted modest overgrowth of vancomycin-resistant enterococci when exposure occurred during treatment. Neither agent promoted colonization with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae.