In vitro antimicrobial activity of piperacillin and seven other β-lactam antibiotics against Neisseria gonorrhoeae and Haemophilus influenzae, including β-lactamase producing strains

Abstract

β-Lactamase negative (β-lac⁻) and positive (βlac⁺) strains of Neisseria gonorrhoeae and Haemophilus Influenzae were tested for susceptibility to piperacillin and seven other beta-lactam antibiotics. Piperadillin was the most active penicillin on the β-lac⁻ and β-lac⁺ gonococci. All penicillins were very active on β-lac⁻H. Influenzae, but carbenicillin and ticarcillin were most active on β-lac⁺ strains; piperacillin was more active than ampicillin on those strains. Cefamandole was the most active cephalosporin tested against both genera, and did not significantly vary for β-lac⁻ and β-lac⁺ strains.