David C Okechukwu¹, Amaka A Ogbuike¹, Malachy C Ugwu², Clara C Aguokogbuo³ , Dinebari P Berebon¹, Restus C Onwusoba¹, Precious A Okechukwu⁴, Somtochukwu A Evurani¹, Osita C Eze¹, Stephen C Emencheta^{1, 5}

Abstract

Purpose: The susceptibility studies of Staphylococcus aureus (S. aureus) isolated from healthy personnel and students at the University of Nigeria, Nsukka, were investigated. Methods: S. aureus was isolated by collecting swab specimens from the skin, hand, and nose of healthy personnel and students from various Departments and Faculties within the University of Nigeria, Nsukka. The colonies were isolated and identified using standard biochemical tests. Antibiotic susceptibility was tested using Kirby-Bauer disk diffusion method with standard Oxoid antibiotic disks and their inhibition zone diameters (IZDs) were measured. The IZD50 and IZD95 were calculated statistically. Minimum Inhibitory Concentration (MIC) of selected antibiotics against isolates was determined by agar dilution method. Results: A total of 84 Staphylococcal isolates were obtained. Fifty isolates (59.5%) were S. aureus, and the remaining 40.5 % were other Staphylococcal species. The percentage of S. aureus isolated from skin, hand, and nose samples was 54, 32, and 14 %, respectively. The IZD50 and IZD95 ranged from 0.00 - 29.25 and 14.50 - 37.60 mm, respectively. The multiple antibiotic resistance (MAR) index ranged from 0.0 – 0.7, with 90 % of isolates exhibiting MAR ≥ 0.2. The MIC values of selected antibiotics (amoxicillin, ciprofloxacin and ceftriaxone) against S. aureus isolates ranged from 0.780 - 50.000, 0.195 - 100.000, and 1.563 - 25.000 μg/mL, respectively. Conclusion: Isolates collected from skin, hands and nose of healthy personnel at the University of Nigeria, Enugu, harbour pathogenic S. aureus in substantial amounts, which are multidrug resistant to some available antibiotics. The results underscore the importance of maintaining continuous surveillance, adhering to proper hygiene, and utilizing antibiotics rationally.