[Fosfomycin susceptibility of clinical isolates from otorhinolaryngological infections].

To investigate the clinical and bacteriological usefulness of orally administered fosfomycin calcium (FOM), the susceptibility of 558 strains to FOM was determined. These strains were isolated at our Center, between Feb. 1982 and Feb. 1983 from otorhinolaryngological infections. Several other drugs were also tested on the same strains for comparison. The results were as follows. The MIC80 of FOM was 6.25 micrograms/ml against each of aerobic Gram-positive cocci such as S. aureus, S. pyogenes, S. pneumoniae, anaerobic Gram-positive cocci such as Peptococcus spp., and H. influenzae. P. mirabilis, indole-positive Proteus spp., P. aeruginosa and K. pneumoniae were inhibited, respectively, at 3.13, 12.5, 12.5 and 50 micrograms/ml. Most of the MICs were between 3.13 and 12.5 micrograms/ml, and the difference between the MIC50 and the MIC90 was only 1 to 2 tubes since there were few resistant strains. With the comparative drugs, there was a reduction seen in the sensitivities of pipemidic acid (PPA), ampicillin (ABPC), and cephalexin (CEX) against, respectively, P. aeruginosa, beta-lactamase-producing H. influenzae and S. aureus. FOM showed good and constant sensitivity for the weakly PPA-sensitive P. aeruginosa, weakly ABPC-sensitive beta-lactamase-producing H. influenzae and weakly CEX-sensitive S. aureus. The MICs of FOM against the main problematic isolates from otorhinolaryngological infections were mostly between 3.13 and 12.5 micrograms/ml, including the above weakly PPA-, ABPC- and CEX-sensitive strains. Based on these values, FOM may be said to have moderate antibacterial efficacy when administered orally in the usual dose.(ABSTRACT TRUNCATED AT 250 WORDS)