ANIMAL TOXICITY STUDIES OF A NEW ANTIBIOTIC, LINCOMYCIN

Impact of lincosamides antibiotics on the composition of the rat gut microbiota and the metabolite profile of plasma and feces

The importance of the gut microorganisms and their wide range of interactions with the host are well-acknowledged. In this study, lincomycin and clindamycin were used to modulate microbial communities of Wistar rats to gain a comprehensive understanding of the implications of microbiome alterations. A metabolomics approach and taxonomic profiling were applied to characterize the effects of these antibiotics on the functionality of the microbiome and to identify microbiome-related metabolites. After treatment, the diversity of the microbial community was drastically reduced. Bacteroidetes and Verrucomicrobia were drastically reduced, Tenericutes and Deferribacteres completely disappeared, while abundance of Firmicutes and Proteobacteria were highly increased. Changes in plasma and feces metabolites were observed for metabolites belonging mainly to the class of complex lipids, fatty acids and related metabolites as well as amino acids and related compounds. Bile acid metabolism was markedly affected: taurocholic acid, glycochenodeoxycholic acid and cholic acid presented abrupt changes showing a specific metabolite pattern indicating disruption of the microbial community. In both plasma and feces taurocholic acid was highly upregulated upon treatment whereas glycochenodeoxycholic acid was downregulated. Cholic acid was upregulated in feces but downregulated in plasma. These results show that changes in the gut microbial community lead to alterations of the metabolic profile in blood and feces of the host and can be used to identify potentially microbiome-related metabolites. This implies that metabolomics could be a suitable tool to estimate the extent of changes induced in the intestinal microbiome with respect to consequences for the host.

Cecal toxin(s) from guinea pigs with clindamycin-associated colitis, neutralized by Clostridium sordellii antitoxin

The cecal contents of guinea pigs with clindamycin-associated colitis contained a heat-labile toxin. This toxin was lethal for guinea pigs and mice, produced vascular permeability in the skin of rabbits, and was cytotoxic in tissue culture. The lethality in mice, vascular permeability in rabbit skin, and cytotoxicity in tissue culture monolayers were neutralized by Clostridium sordellii antitoxin.

Pharmacological studies with lincomycin in late pregnancy

The placental transmission of lincomycin was studied in 60 patients in late pregnancy. A peak maternal blood level of 12.5 mug/ml was recorded 45 minutes after injection, and detectable levels were still present up to 42 hours after a single injection. A peak cord blood level of 2.7 mug/ml was recorded 55 minutes after injection; cord blood levels were about a quarter of the maternal blood levels, and in most cases no levels were detectable 24 hours after a single injection. The passage of lincomycin into and out of the liquor was slower and more variable, but some hours after injection the liquor levels were always higher than the maternal or cord blood levels, and detectable levels were still present in the liquor 52 hours after a single injection. Repeated injections did not lead to any significant accumulation of lincomycin. The only side effect was a possible case of neuromuscular block in a mother delivered by caesarean section. No infant was adversely affected.