In Vitro Activity of Penem-1 in Combination with β-Lactams against bla KPC -Possessing Klebsiella pneumoniae Isolates

In Vitro Activity of Penem-1 in Combination with ␤-Lactams against bla KPC -Possessing Klebsiella pneumoniae Isolates ᰔThe widespread dissemination of bla KPC -possessing Klebsiella pneumoniae isolates represents a serious threat for hospitalized patients (4, 8).bla KPC -possessing K. pneumoniae isolates are resistant to all ␤-lactams, commercially available ␤-lactam-␤-lactamase inhibitor combinations, quinolones, and frequently to aminoglycosides (5, 8).Furthermore, bla KPC -possessing K. pneumoniae isolates can manifest a phenotype of nonsusceptibility to tigecycline and colistin (6, 7).As a result, new therapeutic strategies against infections due to bla KPCpossessing K. pneumoniae isolates should be quickly developed.Penem-1 (Wyeth Research) is a novel serine-reactive ␤-lactamase inhibitor with potent activity against class A, C, and D enzymes (1, 10).We recently demonstrated that this