@article{mbs:/content/journal/micro/10.1099/00221287-58-3-301, author = "NEU, H. C. and WARZ, H. S.", title = "Resistance of Escherichia Coli and Salmonella Typhimurium to Carbenicillin", journal= "Microbiology", year = "1969", volume = "58", number = "3", pages = "301-305", doi = "https://doi.org/10.1099/00221287-58-3-301", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-58-3-301", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "SUMMARY Carbenicillin, a 9-alpha carboxybenzyl penicillin, is bactericidal only for Escherichia coli strains which are resistant to less than 125 μg./ml. of ampicillin. All E. coli and Salmonella typhimurium strains in which penicillinase is a surface enzyme are resistant to carbenicillin. E. coli and S. typhimurium strains in which production of beta-lactamase is episomally mediated are resistant to both ampicillin and carbenicillin. A non-hydrolyzable penicillin (methicillin or dicloxacillin) does not allow carbenicillin to exert its antibacterial effect against resistant strains of E. coli, Pseudomonas, Klebsiella or Enterobacter. Carbenicillin shows no synergy with penicillinase-resistant penicillins.", }