Abstract
Seventy-one clinical isolates of 5 species of group D Streptococcus (Enterococcus) were tested for susceptibility to 15 antibiotics at pH 5.0, 7.4, and 8.5. Penicillin G, ampicillin, cephalothin, cephaloridine, and novobiocin were considerably more active against all strains at pH 5.0 than in the more alkaline media. On the other hand, lincomycin, clindimycin, erythromycin, and gentamicin were moderately to markedly more active at pH 8.5. No important differences were noted in the susceptibility of the strains to kanamycin and streptomycin, at the pH levels tested, but the organisms were quite resistant to them in these tests. The various species differed quantitatively in their susceptibility to the individual drugs and in the effects of pH. The size of the inoculum also had a variable effect on susceptibility, depending on the species of Enterococcus, the antibiotics, and the pH of the test medium. The data suggest that, in the antibiotic treatment of urinary tract infections caused by Enterococcus, attempts should be made to achieve the optimum pH in the urine, particularly in view of the fact that organisms of this group are often resistant to several antibiotics in the usual tests.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- HAIGHT T. H., FINLAND M. Observations on mode of action of erythromycin. Proc Soc Exp Biol Med. 1952 Oct;81(1):188–193. doi: 10.3181/00379727-81-19817. [DOI] [PubMed] [Google Scholar]
- Sabath L. D., Gerstein D. A., Loder P. B., Finland M. Excretion of erythromycin and its enhanced activity in urine against gram-negative bacilli with alkalinization. J Lab Clin Med. 1968 Dec;72(6):916–923. [PubMed] [Google Scholar]
- Sabath L. D., Lorian V., Gerstein D., Loder P. B., Finland M. Enhancing effect on alkalinization of the medium on the activity of erythromycin against gram-negative bacteria. Appl Microbiol. 1968 Sep;16(9):1288–1292. doi: 10.1128/am.16.9.1288-1292.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sabath L. D. Synergy of antibacterial substances by apparently known mechanisms. Antimicrob Agents Chemother (Bethesda) 1967;7:210–217. [PubMed] [Google Scholar]
- Toala P., McDonald A., Wilcox C., Finland M. Susceptibility of group D streptococcus (enterococcus) to 21 antibiotics in vitro, with special reference to species differences. Am J Med Sci. 1969 Dec;258(6):416–430. doi: 10.1097/00000441-196912000-00006. [DOI] [PubMed] [Google Scholar]
- ZAGAR Z. Sensitivity of E. coli, Ps. aeruginosa and B. proteus to erythromycin in various pH culture media. Chemotherapia (Basel) 1963;6:82–89. [PubMed] [Google Scholar]