Characterization and distribution of Citrobacter strains in a university hospital

OBJETIVE. a) To identify Citrobacter strains following the conventional bio chemical reaction of Brenner and col; b) to evaluate the sensitivity and sp ecificity of the O'Hara's method compared with Brenner's method, and c) to determine the rate and distribution of the strains in the clinical isolates . MATERIAL AND METHODS. One hundred and twenty two clinical isolates, charact erized as Citrobacter spp. were collected between May of 1994 and August of 1997. Clinical isolates included impatients and outpatients from Hospital de Clinicas. Strains were identified following the methods of Brenner and O 'Hara. RESULTS. Methods of Brenner identified 111 of 122 strains: C. freundii 59 o f 111; C. koseri 18 of 111; C. werkmanii 15 of 111; C. braakii 9 of 111; C. youngae 6 of 111 and C. amalonaticus 4 of 111. O'Hara's methods identified 104 of 111 strains (94%). C. freundii was recov ered most frequently from urine and feces (p Fisher <0.026 and 0.039 respec tively), while C. koseri was isolated from urine principally (p Fisher <0.0 372). CONCLUSIONS. The genus Citrobacter is and important oportunistic pathogen t hat can be identified in clinical microbiology's laboratories using O'Hara' s method.