Involvement of Fe uptake systems and AmpC β-lactamase in susceptibility to the siderophore monosulfactam BAL30072 in Pseudomonas aeruginosa.

ABSTRACT: BAL30072 is a monosulfactam conjugated with an iron-chelating dihydroxypyridone moiety. It is active against Gram-negative bacteria, including multidrug-resistant Pseudomonas aeruginosa. We selected mutants with decreased susceptibilities to BAL30072 in P. aeruginosa PAO1 under a variety of conditions. Under iron-deficient conditions, mutants with overexpression of AmpC β-lactamase predominated. These mutants were cross-resistant to aztreonam and ceftazidime. Similar mutants were obtained after selection at >16× the MIC in iron-sufficient conditions. At 4× to 8× the MIC, mutants with elevated MIC for BAL30072 but unchanged MICs for aztreonam or ciprofloxacin were selected. The expression of ampC and the major efflux pump genes were also unchanged. These BAL30072-specific mutants were chara

SUBMITTER: van Delden C 

PROVIDER: S-EPMC3632904 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature