Effect of Gentamicin and Amoxicillin on methicillin resistant Staphylococcus aureus (MRSA) against different time and concentrations

Abstract

Staphylococcus aureus (S. aureus) is a gram positive coccal bacterium which is normally a skin flora but may cause opportunistic infections such as skin and soft tissue infections, bacteremia and necrotizing fasciitis. Twenty (20) clinical specimens were collected from healthy (10) persons and unhealthy (10) persons. These samples were collected from different sources such as ear, wound, vagina swab and urine. A total of (10) S. aureus isolates was obtained and screened for methicillin resistance by using oxacillin disc (10kg). Ten S. aureus were found to be methicillin resistant. Sensitivity test of these methicillin resistant Staphylococcus aureus (MRSA) revealed resistance to all penicillin derivatives and to a greater extent gentamicin, argumetin and ofloxacin. The effect of time duration on the killing kinetics of gentamicin, amoxicillin and a combination of the two MRSA was also determined. Result showed that MRSA was susceptible to gentamicin at a range of (2.5 -4.2) at a concentration of 1000mg/ml and (2.0 -4.3) at a concentration of 500mg/ml and amoxicillin at a range of (1.4 -3.1) at a concentration of 1000mg/ml and (1.4 -2.9) at a concentration of 500mg/ml of the antibiotics and the combination of these antibiotics which has a range of (3.3 -3.8) at a concentration of 1000mg/ml and (2.7 -3.7) at a concentration of 500mg/ml will give a synergy and it can be used against MRSA.