F.O. EKHAISE

Indoor air quality is an important determinant of public health, particularly in food-handling environments where airborne microorganisms can contaminate food and surfaces, leading to potential disease transmission. This study was conducted to isolate and identify airborne bacterial species from private eateries within the University of Benin (UNIBEN), Edo State, Nigeria. The study was carried out in two selected eateries, University Buka and Home and Away. A cross-sectional study design was adopted, and airborne bacterial samples were collected over a three-week period using the settle plate method. Sterile nutrient agar plates were exposed for 15 minutes at a height of approximately 1 meter above the ground to allow the natural settling of airborne bacteria. The plates were then incubated and analyzed for total bacterial load, followed by morphological, Gram staining, and biochemical characterization to identify the bacterial species present. The results showed that the mean bacterial load ranged from 0.7 ± 0.04 × 10² CFU/m³ at Home and Away in Week 3 (the lowest) to 3.22 ± 0.5 × 10² CFU/m³ at University Buka in Week 1 (the highest). Six bacterial species were isolated and identified: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella spp., Bacillus spp. and Pseudomonas aeruginosa. Among these, S. aureus was the most frequently occurring species (26.8%), followed by Bacillus spp. (21.4%) and S. epidermidis (17.9%), while E. coli, Klebsiella spp., and P. aeruginosa had lower frequencies. Antibiotic susceptibility testing revealed widespread multidrug resistance among the isolates. Klebsiella spp. demonstrated the highest resistance (88.9%) with a Multiple Antibiotic Resistance (MAR) index of 0.89, followed by E. coli (0.78), S. epidermidis and P. aeruginosa (0.67 each), S. aureus (0.56), and Bacillus spp. (0.44). Ofloxacin (OFL) and gentamicin (GEN) were the most effective antibiotics, while ampicillin (AMP), ampiclox (AMPX), and clarithromycin (CLT) were the least effective across most isolates. The public health assessment based on bacterial load classification revealed that University Buka consistently recorded high contamination levels (H) in all three weeks, while Home and Away maintained low levels (L). The presence of antibiotic-resistant athogens such as S. aureus, Klebsiella spp., and P. aeruginosa in indoor air poses significant health risks, particularly to food handlers and consumers. This study highlights the presence of potentially pathogenic and multidrug-resistant airborne bacteria in private eateries within UNIBEN, emphasizing the need for improved ventilation, regular disinfection, and strict adherence to hygiene practices to safeguard public health.

Airborne bacteria from refuse dumpsites represent a significant environmental and public health concern, as these microorganisms can disperse widely, contaminate the surrounding air, and serve as potential reservoirs of pathogenic and antibiotic-resistant species. This study investigated the isolation and identification of airborne bacterial isolates from selected refuse dumpsites within the University of Benin, Ugbowo Campus, Benin City, Nigeria. A cross-sectional study design was employed, and air samples were collected from three major dumpsites—Hall 3, Hall 4, and the Faculty of Life Sciences, using the settle plate method. Results showed that the highest bacterial load recorded at the Hall 3 dumpsite in Week 2 (7.6 ± 0.42 × 10³ cfu/m³) and the lowest at the Faculty of Life Sciences in Week 1 (3.9 ± 0.22 × 10³ cfu/m³). Six bacterial species were identified: Staphylococcus aureus, Bacillus spp. Escherichia coli, Klebsiella spp. Pseudomonas spp. and Proteus sp. Among these, Staphylococcus aureus had the highest frequency of occurrence (26.5%), while Pseudomonas spp. and Proteus sp. were the least frequent (10.3% each). The antibiotic susceptibility tests revealed that S. aureus and Proteus sp. exhibited the highest susceptibility (77.8%) and the lowest resistance (22.2%), whereas E. coli displayed the lowest susceptibility (33.3%) to tested antibiotics. Ofloxacin, ciprofloxacin, and gentamicin were the most effective antibiotics, while ampicillin and ampiclox showed the least efficacy.The Multiple Antibiotic Resistance (MAR) indices ranged from 0.44 to 0.89, with Klebsiella spp. exhibiting the highest MAR index (0.89), suggesting exposure to environments with high antibiotic selective pressure. The study underscores the need for improved waste management practices, regular sanitation, and environmental monitoring to minimize microbial air pollution and prevent the spread of resistant bacteria.