Isolation and identification of etiological agents found in body fluids can be of critical importance for the recovery of patients suffering from potentially-severe infections, which are often followed by serious sequels. Eighty-two samples of different body fluids were analyzed using two different methods: (1) the conventional culture method (agar plating) and (2) the enrichment culture technique, using the Bact/Alert blood culture bottle. The number of positive cultures increased on average from 9.7% to 23.1% with the enrichment culture technique. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were the most frequently isolated bacteria. The enrichment method could provide a more accurate means the identifying etiological agents.

O isolamento e identificação do agente etiológico causador de infecção a partir de líquidos biológicos podem ser um fator crítico para a recuperação da saúde do paciente, pois estas infecções geralmente são graves e deixam seqüelas. Neste trabalho foram analisadas 82 amostras de diferentes líquidos biológicos, comparando os resultados da coloração de Gram com os das culturas, além de verificar incidência dos microrganismos isolados. O Gram apresentou sensibilidade e especificidade de 62,5% e 93,9% respectivamente. Pseudomonas aeruginosa, Escherichia coli e Staphylococcus aureus foram as bactérias mais isoladas. Concluiu-se que a Coloração de Gram pode ser uma ferramenta útil na análise dos líquidos biológicos, contribuindo no diagnóstico preliminar destas infecções. SENSITIVITY OF GRAM STAINING FOR EARLY DIAGNOSTIC OF INFECTIONS IN STERILE BODY SITES Abstract Isolation and identification of an etiologic agent from biological fluids can be a critic factor for the clinical outcome of the patient, because this infection can generally be severe and cause sequels. Eighty-two different samples of biological fluids were analyzed through the Gram staining method. The results of Gram were compared with those obtained with culture, and the incidence of isolated microorganisms was also analyzed. The Gram staining presented 62.5% and 93.9% of sensitivity and specificity, respectively. Among all types of isolated and identified bacteria, P. aeruginosa, E. coli and S. aureus were the commonest ones. It was concluded that the Gram staining could be a useful tool on analysis of biological fluids, contributing for the previous diagnostic of these infections.