ABSTRACT
The decimal assay for additivity (DAA) method was used to evaluate the in vitro interaction of glycine (Gly) with penicillin G (Pen G); cloxacillin (Clox) and ampicillin (Amp) against a clinical isolate of Staphylococcus aureus. In the interaction between Pen G/glycine with biological equivalent factor (BEF) 5 mg/62 mg; the decimal combination of 4 parts Pen G and 6 parts glycine showed amtagpmos; wjo;e ptjers sjpwed addotive effect In the interaction between Clox/glycine with BEF 1.26 og/62.5 mg ony 7:3 combination gave a synergistic effect. Others showed antagonism. In Amp/glycine combination with BEF; 1.74 og/62.5 mg; the decimal combinations of 4:6 gave additive effect; 9:1 gave synergistic effect while 7:3 combinaiton gave indifferent effect