ABSTRACT
The aim of the present study was to investigate the effect of chlorhexidine at subinhibitory concentration (50% minimal inhibitory concentration (MIC)) on the growth, cytolysin expression and phagocytosis of Streptococcus agalactiae ATCC 13813. Bacterial growth with and without chlorhexidine treatment was monitored by turbidity measurements, and exocytolysins were estimated by neutral red uptake assay by the McCoy cell line. The phagocytic process was evaluated using luminol-enhanced chemiluminescence to follow the respiratory burst of polymorphonuclear neutrophils exposed to bacteria. Chlorhexidine-treated culture did not exhibit a detectable decrease in cell growth, and no statistically significant reduction in the respiratory burst of polymorphonuclear neutrophils was observed. However, growth in the presence of chlorhexidine resulted in a significant reduction of S. agalactiae exocytolysins. Although 50% MIC of chlorhexidine did not interfere with S. agalactiae growth and phagocytosis, the knowledge that this concentration was still able to alter some bacterial virulence parameters may be useful in its therapeutic applications.
Subject(s)
Chlorhexidine/pharmacology , Cytotoxins/metabolism , Streptococcus agalactiae/drug effects , Streptococcus agalactiae/pathogenicity , Virulence Factors/metabolism , Animals , Humans , Luminescence , Microbial Sensitivity Tests , Neutrophils/immunology , Neutrophils/microbiology , Phagocytosis , Rats , Respiratory Burst , Streptococcus agalactiae/growth & development , VirulenceABSTRACT
Avaliou-se a produção de DNases, fibrinolisina e coagulase por isolados de Fusobacterium nucleatum obtidos de pacientes com doença periodontal e de indivíduos sadios. Verificou-se que 72,22 por cento dos isolados de pacientes e 73,68 por cento dos sadios produziram enzimas capazes de degradar DNA, enquanto a produção de coagulase e fibrinolisina somente foi nos isolados de pacientes com doença periodontal. Concluiu-se que, quanto aos fatores de virulência estudados, os isolados de F. nucleatum obtidos de pacientes não diferem significativamente dos isolados de sadios