Antibiotic susceptibility of Staphylococcus aureus from nasal isolates in students from northern Peru

Abstract

Objectives: To determine the antibiotic susceptibility profile of Staphylococcus aureus, in Biology, Nursing and Medicine students of the Pedro Ruiz Gallo-Lambayeque National University. Methods: Samples were collected by means of nasal swabs. Primary isolation was performed on Salt Mannitol Agar, for the recovery and identification of Staphylococcus aureus from October 2015 to March 2016. The bacterial susceptibility test was performed by the antimicrobial sensitivity test by the diffusion disc method. Results: 43 positive cultures were isolated for Staphylococcus aureus, which represented 28.6%; 107 samples were negative, representing 71.4%. It was determined that, 90.6% of the strains were resistant to Oxacillin, 81.3% to Sulfamethoxazole - Trimethoprim, 95.3% to Penicillin, 34.8% to Cefoxitin, being all strains 100% sensitive to Imipenem and Vancomycin. Evaluation of the cross reaction resulted in 2.6% of the strains showing resistance to Ceftazidime, 12.8% to Azithromycin, 15.4% to Cefotaxime, and 20.9% to Gentamicin; on the contrary they were 100% sensitive to Amikacin, Ciprofloxacin, Ceftriaxone and Cefuroxime. Conclusions: 28.6% of the total population in the study was positive for Staphylococcus aureus, 90.6% of the strains were resistant to Oxacillin, and all the strains were sensitive to Imipenem. The Professional School of Biological Sciences presented the highest frequency of Staphylococcus aureus isolates.