ASSESSMENT OF A FLUOROQUINOLONE, 3 BETA-LACTAMS, 2 AMINOGLYCOSIDES, AND A CYCLINE IN TREATMENT OF MURINE YERSINIA-PESTIS INFECTION

Amoxicillin, cefotaxime, ceftriaxone, gentamicin, doxycycline, and ofl oxacin were active in vitro, like the reference drug streptomycin, aga inst the virulent strain Yersinia pestis 6/69M. The comparative effica cies of these drugs in vivo were evaluated in a standardized and repro ducible mouse model of systemic infection. Each antibiotic was injecte d intravenously once, at 24 h postinfection, and then repeatedly durin g 48 h. In vivo results were measured by counting the viable bacteria recovered from the whole spleens of mice sacrificed at selected times. All the drugs were manifestly successful; ceftriaxone, ofloxacine, an d the reference drug were the most effective. Therefore, gentamicin an d doxycycline could be used, depending on the clinical forms of the Y. pestis infection. Further investigations on beta-lactams, especially those used in the present study, could be carried out to confirm or no t confirm their activities against Y. pestis. Ofloxacin appeared to be as active and to perform as rapidly as streptomycin in the treatment of murine Y. pestis infection, which is in agreement with the previous successes obtained,vith the use of fluoroquinolones in the treatment of murine infections caused by other pathogenic yersiniae.