Impact of azlocillin on the colon microflora.

To evaluate the impact of parenteral azlocillin therapy on human colon microflora, faecal specimens were taken from 6 patients before, during and after therapy for analysis of the microflora. In 2 patients major changes took place. Thus the numbers of streptococci, Escherichia coli, anaerobic cocci, lactobacilli, clostridia and bacteroides decreased markedly during therapy. One of these patients was colonized with azlocillin-resistant Enterobacter cloacae. The other 4 patients had only minor changes in the microflora. Variations between patients seem to exist. Pronounced alterations in the colonic flora may have clinical implications.