Bornside G H
Appl Microbiol. 1968 Oct;16(10):1507-11. doi: 10.1128/am.16.10.1507-1511.1968.
Synergistic antibacterial effects of mixtures of ampicillin and cloxacillin and induced penicillinases were investigated in 48 strains of Proteus. The serial tube dilution method was used to determine the minimal inhibitory concentration of ampicillin, cloxacillin, and 2:1 and 1:1 mixtures of ampicillin and cloxacillin. Production of penicillinases was determined by the cellulose acetate membrane method, with ampicillin, cloxacillin, mixtures of ampicillin and cloxacillin, penicillin G, and cephalothin as inducing agents and as substrates for penicillinase. Synergism occurred against P. morganii, but against no other species. The 1:1 ampicillin-cloxacillin combination was synergistic against 13 of 17 P. morganii strains; the 2:1 combination was synergistic against only 9 strains. Penicillinases, demonstrated in all species except P. mirabilis, hydrolyzed penicillin G and cephalothin. Although only P. vulgaris hydrolyzed ampicillin, no species of Proteus hydrolyzed cloxacillin or the ampicillin-cloxacillin mixtures. Penicillinases were, however, induced by ampicillin, cloxacillin, and the mixtures. There was no relationship between production of penicillinase and synergism with mixtures of ampicillin and cloxacillin.
对48株变形杆菌研究了氨苄西林与氯唑西林混合物及诱导产生的青霉素酶的协同抗菌作用。采用连续试管稀释法测定氨苄西林、氯唑西林以及氨苄西林与氯唑西林2:1和1:1混合物的最低抑菌浓度。通过醋酸纤维素膜法测定青霉素酶的产生情况，以氨苄西林、氯唑西林、氨苄西林与氯唑西林的混合物、青霉素G和头孢噻吩作为诱导剂及青霉素酶的底物。对摩根氏变形杆菌有协同作用，但对其他菌种无协同作用。1:1的氨苄西林 - 氯唑西林组合对17株摩根氏变形杆菌中的13株有协同作用；2:1组合仅对9株有协同作用。除奇异变形杆菌外，所有菌种均显示能水解青霉素G和头孢噻吩的青霉素酶。虽然只有普通变形杆菌能水解氨苄西林，但变形杆菌属的任何菌种均不能水解氯唑西林或氨苄西林 - 氯唑西林混合物。然而，氨苄西林、氯唑西林及混合物可诱导产生青霉素酶。青霉素酶的产生与氨苄西林和氯唑西林混合物的协同作用之间无关联。
