The effects of subinhibitory concentrations of various antibiotics on phagocytosis of Streptococcus faecalis.

This study reports the effects of subinhibitory concentrations of the antibiotics, clindamycin, gentamicin, moxalactam, and penicillin G, against 6 blood isolates of Streptococcus faecalis to determine possible enhancement of phagocytosis. In addition, combinations of penicillin G plus streptomycin, penicillin G and gentamicin, and clindamycin plus gentamicin were studied to determine synergistic growth inhibition. Results suggest no observable effect in phagocytosis from subinhibitory concentrations of the studied antibiotics singly or in combination. The number of viable intracellular Str. faecalis were also not affected by pre-treatment with antibiotics.