Pneumococcal LytA autolysin, a potent therapeutic agent in experimental peritonitis-sepsis caused by highly beta-lactam-resistant Streptococcus pneumoniae

Abstract

The in vitro and in vivo antipneumococcal activities of the main pneumococcal autolysin (LytA) and Cpl-1, a lysozyme encoded by phage Cp-1, were studied. Intraperitoneal therapy with LytA or high-dose Cpl-1 remarkably reduced peritoneal bacterial counts (>5 log(10) CFU/ml) compared with those for the controls. After intravenous injection, LytA was the most effective treatment.

FIG. 1.

Antipneumococcal activities in the peritoneal fluid (A and C) and in the blood (B and D) of lytic enzymes or CTX 4 h after administration by the i.p. (A and B) or i.v. (C and D) route in mice with β-lactam-resistant S. pneumoniae peritonitis-sepsis. Each point represents one mouse; five to six animals were included in each group; the mean ± standard deviation for each group is also shown. In panel B, the label 1 indicates that three animals treated with LytA i.p. showed bacterial clearance from the blood and the label 2 indicates that two animals treated with CTX i.p. also showed bacterial clearance from the blood. *, statistically significant difference compared to the results for the control.