BACTERIAL ISOLATES

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.

The antibacterial activities of thyme (Thymus vulgaris) against some Gram positive isolates such as Staphylococcus aureus and interococcus faecalis were assayed using ethanol extract. The agar-well and paper disc diffusion method were used to determine the inhibitory effect of the thyme leaves on the tested microorganism. The extract produced different zone of inhibition on the tested organism. The ethanol extract had the highest antibacterial effect against interococcus faecalis (21.6±3.51 mm) at 100% and Staphylococcus aureus has the lowest zone of inhibition (21.3±3.2l mm) at 100%, while at 75% Enterococcus faecalis had the highest zone of inhibition (l 7±2.64 mm) and Staphylococcus aureus has the lowest zone of inhibition (12.3±2.5l mm), while at 62% Enterococcus faecalis showed the highest zone of inhibition (12±3.46 mm) while Staphylococcus aureus has the lowest zone of inhibition (11.3±1.52 mm). The ethanol extract had the highest antibacterial effect against Staphylococcus aureus (20.6±4.04 mm) at 87% and Enterococcus faecalis has the lowest zone of inhibition (20.3±1.52 mm) at 87% while at 50% Staphylococcus aureus showed the highest zone of inhibition (6.33±1.15 mm) while Enterococcus faecalis has the lowest zone of inhibition (5±0 mm). Among these isolates, Enterococcus faecalis were highly sensitive to the thyme oil at different percentage (100%, 75%, 62%) while Staphylococcus aureus were little more sensitive to the thyme oil at 87% and 50% using the same solvent (ethanol). The increase in multidrug resistant strains of pathogenic microorganism has led to extensive phytochemical and pharmacological studies of Thymus vulgaris as an important source of medicinal substances which possess antibacterial properties and their effective medicinal application, as well as use in pharmaceutical, food and cosmetic industries

Fomites are generally considered as any inanimate object that can serve as a means of transferring pathogens to a new host. Table surfaces which are fomites can be a major source of spread of infectious diseases. The main aim of the study is to enumerate, isolate and identify bacteria from Environmental Management and Toxicology (EMT) students lecture tables at University of Benin as well as to determine the antimicrobial susceptibility test of the bacterial isolates. Samples were collected twice on a weekly basis using a sterile swab. Methods involved in the isolation and identification of the bacteria were serial dilution, Gram staining, biochemical test which include oxidase, catalase, indole, urease, sugar fermentation and potassium hydroxide test, as well as antimicrobial sensitivity test. The probable isolates identified were Staphylococcus aureus, E. coli, Klebsiella spp., Pseudomonas spp. and Enterobacter aerogenes, with the second week having a higher number of bacterial population and isolates. Unhygienic practices by the students accounts for these isolates.