Multidrug-resistant Proteus rettgeri: an emerging problem.

The recent development of multidrug-resistant strains of Proteus rettgeri prompted a 6-year review of infections with this organism. Ninety percent of infections involved the urinary tract. Fifty percent of infections occurred on the neurology ward, where a progressive annual increase in attack rate was noted. Statistically significant (P less than 0.005) increases in total length of hospitalization, length of hospitalization before infection, presence and duration of indwelling Foley catheterization, prior exposure to antibiotics, and the prevalence of paraplegia were present in P. rettgeri urinary tract infections as compared with a control group. A progressive increase in resistance to kanamycin, streptomycin, ampicillin, and gentamicin occurred during 6 years. Disc diffusion sensitivities of recent isolates show total resistance to commonly tested antibiotics. Eighty percent or more of strains are inhibited, however, by 3.13 mug/ml of amikacin and cefoxitin, and 0.4 mug/ml of ticarcillin.