Antibiotic sensitivity pattern of staphylococcus aureus strains isolated from patients at Karachi

ABSTRACT

To see the antibiotic sensitivity pattern of Staphylococcus aureus strains. Design: The susceptibility of Staph. aureus strains to oxacillin, six other beta lactam antibiotics and ten non-beta lactam antimicrobial agents was determined on Mueller Hinton agar by disc diffusion method. Staph. aureus strain ATCC 25923 was used as standard strain for quality control. Settings Patients from five large public and private sector hospitals of Karachi. Subjects: Prospective study involving 200 strains of Staph. aureus isolated from patients suffering from hospital acquired or community acquired infections. Main outcome measures: Antibiograms of Staphlococcus aureus strains against beta lactam and non-beta lactam antimicrobial agents. The strains were found highly resistant to penicillin [92%]. All the strains were sensitive to vancomycin, 91% were sensitive to fusidic acid and to rifampicin, 88% to chloraphenicol, 86% to clindamycin and to ofloxacin, 75% to gentamicin, 61% to erythromycin, 41% to tetracycline and 45% to trimethoprim-sulfamethoxazole. About 25% strains were resistant to oxacillin [MRSA]. Almost the same number were resistant to amoxicillin-clavulanic acid combination and to cephalosporins. Most of the MRSA strains were also resistant to the non-beta lactam antimicrobials while MSSA strains were mostly sensitive to the beta lactam and non-beta lactam antimicrobials. Antibiotic resistance in Staphlococcus aureus is very high. Most of the MRSA strains are multiply resistant towards the commonly used antibacterials and their prevalence in community is alarmingly high. The situation calls for restrication calls for restriction in the use of antibiotics and adoption of adequate infection control measures: