IN-VITRO ACTIVITIES OF ANTIMICROBIAL AGENTS AGAINST PROTEUS SPECIES FROM CLINICAL SPECIMENS

Two hundred clinical isolates of members of the genus Proteus were def initively identified and their antimicrobial susceptibilities to 12 an timicrobials tested, 176 isolates (88%) being identified as Proteus mi rabilis, 12 strains (6%) as Proteus vulgaris and 12 strains (6%) as Pr oteus penneri. Most strains were isolated from pus (62.5%) and urine ( 34%), but in general there were no significant differences in the rate s of isolation of any of the species by age or sex, although it was no ted that P. vulgaris was only isolated from patients belonging to the older age group (> 5 years). The Proteus spp. were notably susceptible to nalidixic acid, ceftazidime and the aminoglycosides tested, and re sistant to polymyxin B and colistin. The inclination of certain Proteu s species to be susceptible or resistant to certain antimicrobials was noted, but strain differences also existed. The results of the study confirm the importance of performing antimicrobial susceptibility test ing of each Proteus isolate to avoid potentially misleading therapy. T he noted discrepancy in the result of the susceptibility of P. penneri to chloramphenicol as tested by different standard methods merits fur ther investigation.