@article{mbs:/content/journal/micro/10.1099/00221287-68-3-263, author = "Bobrowski, M. and Borowski, E.", title = "Interaction between Carbenicillin andβ-Lactamases from Gram-negative Bacteria", journal= "Microbiology", year = "1971", volume = "68", number = "3", pages = "263-272", doi = "https://doi.org/10.1099/00221287-68-3-263", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-68-3-263", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "SUMMARY The rates of hydrolysis of carbenicillin and of other penicillins and cephalosporins by nine different β-lactamase preparations obtained from Gram-negative bacteria were compared. Enzymes produced by Klebsiella strains, most active against penicillins, as well as β-lactamases synthesized by Escherichia coli and Proteus mirabilis strains hydrolysed carbenicillin, although at relatively lower rates than ampicillin or cephaloridine. In contrast, carbenicillin was extremely resistant to β-lactamases with a predominant cephalosporinase activity as produced by Pseudomonas aeruginosa, Proteus vulgaris and Enterobacter strains. The cephalosporin β-lactamases activity of these enzymes was inhibited by carbenicillin. A considerably increased enzymic activity observed in one strain of Pseudomonas aeruginosa when grown in the presence of carbenicillin or other β-lactam antibiotics was unable to destroy carbenicillin to any measurable extent. A possible permeability barrier to carbenicillin has been demonstrated in some strains.", }