Patterns of oropharyngeal and fecal flora in patients with acute leukemia.

The oropharyngeal and fecal flora in 33 patients hospitalized with acute leukemia was examined. Normal flora predominated on admission. All patients received chemotherapy during the 48 hr after admission and at least one course of antibiotics during hospitalization. By the end of the study, 68% of the initial normal throat flora and 57% of the fecal flora had disappeared. The shift in flora was mainly due to the persistence or acquisition of aerobic gram-negative bacilli. Before antibiotics were given, the normal flora in both sites had already decreased in quantity, and increased numbers of aerobic gram-negative bacilli were found. After the first course of antibiotics, a further decrease in the total number of normal strains was observed. Information obtained from surveillance cultures was helpful for understanding the changes in flora but did not correlate with the microbiology of the infectious processes and could not be used to predict infection.