[In vitro antibacterial activity of balofloxacin (BLFX) against isolates from patients with bacterial enteritis].

In vitro antibacterial activity of balofloxacin (BLFX), a newly developed fluoroquinoline, was compared with that of norfloxacin (NFLX), ofloxacin (OFLX) and ciplofloxacin (CPFX). Bacterial strains used in this experiment were freshly isolated from patients with infectious enteritis just before BLFX therapy. The isolates were 43 strains of Vibrio cholerae O1, 1 strain of Campylobacter sp., 4 strains of Aeromonas spp., 3 strains of Plesiomonas shigelloides, 1 strain of Vibrio mimicus and 1 strain of Vibrio cholerae non-O1. MIC90 of BLFX against 43 strains of Shigella spp., 13 strains of Salmonella spp. and 9 strains of E. coli were 0.39, 0.39, 0.2 micrograms/ml, respectively. All strains of Aeromonas spp. and P. Shigelloides were inhibited by the concentrations under 0.39 and 0.05 micrograms/ml. MIC90 of BLFX, NFLX, OFLX and CPFX against a total of 79 strains were 0.39, 0.2, 0.2 and 0.05 micrograms/ml, respectively.

[In vitro antibacterial activity of fleroxacin (FLRX) against clinical isolates from bacterial enteritis].

Antibacterial activity of fleroxacin (FLRX), a new quinolone antimicrobial, against 36 strains of Shigella app., 14 strains of Salmonella spp., 11 strains of Escherichia coli, 9 strains of Vibrio spp. (including 2 strains of V. cholerae O1), 14 strains of Campylobacter jejuni/coli, 3 strains of Aeromonas spp. and 1 strain of Plesiomonas shigelloides isolated from infectious enteritis patients in this study was determined. Its activity was compared with that of ciprofloxacin (CPFX), norfloxacin (NFLX) and nalidixic acid (NA). The MIC90 values of FLRX were 0.1 microgram/ml against Shigella spp. and E. coli, 0.2 microgram/ml against Salmonella spp. and Vibrio spp., and 12.5 micrograms/ml against C. jejuni/coli MIC90 of FLRX was comparable to that of CPFX and NFLX against Vibrio spp.. Against other species, MIC90 of FLRX were 2- to 4-fold higher than those of CPFX, whereas equal to or 2-fold lower than NFLX. FLRX demonstrated excellent activity against an NA-resistant (MIC: > 100 micrograms/ml) isolate of E. coli, with MIC 0.78 microgram/ml. FLRX showed 8-fold higher activity than NA against other strains. The antibacterial activity of FLRX was compared with that of NA against stocked strains (clinical isolates from August 1989 to February 1991), consisting of 11 strains of Shigella spp., 10 strains of Salmonella spp., 8 strains of E. coli, 10 strains of V. cholerae O1, 10 strains of V. parahaemolyticus and 14 strains of C. jejuni/coli. MICs of FLRX were 0.78 and 12.5-25 micrograms/ml against Shigella spp. and C. jejuni/coli that showed resistance of NA (MIC: > or = 100 micrograms/ml), respectively. Based on the above, although the absolute MICs are low against E. coli and shigella spp., a value of 0.78 micrograms/ml for FLRX suggested that such strains should be considered to be resistant.

[Studies on hemolytic streptococcal infection: 1). Outbreak of group C hemolytic streptococcal infection in Formosan squirrels].

Between mid-October to mid-November 1992, of 500 freely-ranging Formosan and striped squirrels kept at Garden Y in the suburbs of Kanagawa Prefecture, 414 (82.8%) suddenly died one after another by bleeding from the nasal and oral cavities after developing a mild facial swelling. Isolation of microbes including viruses were carried out from the Formosan squirrels that had suddenly died. Various organs from these animals were histologically examined. 1. In bacteriological tests, beta-hemolytic streptococcal strains were isolated in a pure culture from 5 (83.3%) of 6 Formosan squirrels that had died suddenly. By serological analysis, 14 isolated strains were serotyped as group C according to the classification of Lancefield. From their biochemical characteristics, these were identified as Streptococcus equi subsp. zooepidemicus. A drug sensitivity test revealed that ABPC, PCG, SBPC, CMX and CPZ are highly sensitive against the isolates. 2. In the virological test, the viral isolation was applied for three blind passages by primary cultured kidney cells of Formosan squirrels, but no evidence of CPE was obtained. 3. At autopsy, a pathological change was detected mainly in the lungs. Histopathological examinations revealed severe hypertrophic changes of the alveolar wall in the entire pulmonary lobe. Severe congestion, hemorrhagic pneumonia, neutrophils and macrophages infiltration were observed in the hypertrophic alveolar wall. In the other cases, thrombi were observed in the branches of the pulmonary artery. Other organs demonstrated no remarkable histopathological changes. 4. Streptococcal strains were not isolated from the pharynx in all of the employees working at this garden.