Impacts of virulence factors of Streptococcus mutans isolates on the pathogenesis of acute vaginitis

Abstract

Streptococcus mutans, known to be an etiologic agent of dental caries, also causes infective endocarditis. Adherence of these bacteria results from the interaction of adhesions that form part of their structure with salivary components (or other body’s fluids), specifically those that compose the acquired pellicle. In the present study, acute vaginitis samples (vaginal swabs) were investigated from pregnant women patients who were admitted to many hospitals and maternal care centres in Baghdad city of Iraq. Ages of the women ranged from 20 to 30 years (only married women), while all samples were collected during March to July 2009. One hundred and fifty vaginal swabs were collected and cultured on blood agar plate, nutrient agar plates, chocolate agar plates and MacConkey agar plates, then incubated aerobically and anaerobically for 24 h at 37°C. Bacterial diagnosis were done according to macroscopic, microscopic and biochemical tests. The results of recent study showed that the prevalence of bacterial acute vaginitis of pregnant women indicated 18 (12%) as positive cases, while no growth was seen in the rest vaginal swabs (132, 88%). Results of bacterial isolation and identification showed that out of 18 isolates, only 8 (44.4%) isolates were diagnosed as S. mutans while other isolates were distributed to Staphylococcus epidermidis (8, 44.4%) isolates, Staphylococcus aureus (6, 33.3%) isolates, and 5 (27.7%) isolates each for Streptococcus agalactiae, Streptococcus salivaris and Proteus spp. Results of blood hemolysis of S. mutans isolates as virulence factors showed that only two isolates (25%) have the ability to produce hemolycin enzyme, and noticed that four isolates (50%) of S.. mutans were had the ability to produce extracellular protease enzyme on Mg media. Results of antibiotics profile resistance of S. mutans isolates showed that all isolates (100%) were resistant to ampicillin and amoxcillin, whereas seven isolates had also shown resistance in a lesser degree (87.5%) to tetracycline and gentamycin and to cefotaxime (75%) and ciprofloxacin and to erythromycin (62.5%) while all isolates showed high sensitivity (100%) to amoxiclave, doxicyclin and ampiclox antibiotics. S. mutans isolates showed moderate prevalence in the distribution of pathogenic microorganism of acute vaginitis. These isolates had 25% ability of blood hemolysis, and 50% ability to produce protease enzyme. S. mutans vaginal isolates appeared highly (100%) sensitive to amoxiclave, doxicyclin and ampiclox antibiotics, but it had 100% resistance to synthetic penicillin (ampicillin and amoxcillin) and there were different susceptibility to the rest antibiotics used in the study. Key words: Streptococcus mutans, virulence factors, antibiotics susceptibility.