[Effect of DQ-2556, a new cephalosporin derivative, on fecal microflora].

A new cephalosporin derivative antibacterial agent, DQ-2556, was administered intravenously to 4 healthy adult male volunteers at 2 grams per dosage 2 times a day for 5 days, and degrees of effects of drug concentrations on the fecal microflora were investigated. 1. The total viable count remained unchanged during the study period due to the minimal change in the number of members of the family Bacteroidaceae, which were the most dominant organisms. In one of the volunteers, however, the total count was remarkably reduced immediately after the end of administration of the drug. 2. Among the obligate anaerobes, most of the organisms decreased except members of the family Bacteroidaceae. A marked increase of lecithinase-positive clostridia was noted in 2 volunteers. 3. The number of aerobes, including facultative anaerobes, members of the family Enterobacteriaceae were suppressed but bacilli and yeasts showed slight increases. In many cases, increases in enterococci were also observed. 4. DQ-2556 was not detected in the feces from any of the volunteers during the study period. 5. Neither Clostridium difficile nor its toxin D-1 was detected in any of the volunteers. 6. Diarrhoea or other side-effects were not noted in any of the volunteers.