The combined actions of saliva, human amylase and antibiotics on Streptococcus pyogenes and Streptococcus agalactiae
Rotimi, V.O.; Eke, P.I.
East African Medical Journal 62(4): 236-242
1985
ISSN/ISBN: 0012-835X PMID: 2412781 Document Number: 262268
Possible synergistic effects between saliva, human amylase and antibiotics on beta-haemolytic streptococci of groups A and B were investigated by determining the MICs of the antibiotics in the presence or absence of saliva or amylase. No appreciable change was demonstrated in the MICs of penicillin and ampicillin for the two organisms when either saliva or amylase was added. Group B streptococci (GBS) was more resistant to tetracycline and gentamicin than group A streptococci. Significant synergy was demonstrated between saliva or amylase and these two antibiotics. For GBS MIC50 and MIC90 of tetracycline and gentamicin reduced from 128 mg/l each and 32 mg/l each respectively, to 16 mg/l each and 2 mg/l each respectively, by the addition of human amylase. Similar reduction in MIC50 and MIC90 of tetracycline and gentamicin was produced by saliva. Tetracycline or gentamicin trial for the eradication of vaginal or oral carriage of GBS, where .alpha.-amylase concentration is high, may be fruitful when penicillin or ampicillin therapy has failed in carrier states.