Selective antimicrobial modulation of the intestinal microbial flora for infection prevention in patients with hematologic malignancies. Evaluation of clinical efficacy and the value of surveillance cultures.

To confirm the results obtained in an earlier study, the incidence of infection was evaluated in 54 patients (62 periods of admission), nursed in conventional rooms and given a regimen of antimicrobial agents intended to modulate the intestinal flora selectively as a method to prevent infection during severe granulocytopenia. In 62 patients receiving selective antimicrobial modulation (SAM), 18% acquired major infections which was similar to 19% in patients on SAM in an earlier double-blind placebo controlled study and lower than 47% in the controls. Evaluation of a large number of surveillance cultures showed that the presence of specific potentially pathogenic aerobic bacteria was associated with the occurrence of major infection. If the bacterial species in question were not found in the cultures the chance of becoming infected was less than 5%, whereas the chance ranged between 42 and 62% depending on the species involved when these microorganisms were isolated.