DEPARTMENT OF MICROBIOLOGY

Laundry wastewater, a category of greywater, contains various chemical constituents such as soap, suspended solids, oils, perfumes, and other pollutants at high concentrations. This study investigated the prevalence of virulence factors in bacterial isolates obtained from laundry wastewater to highlight their potential health risks. Samples were collected from residential and industrial laundry facilities, and the microbial isolates were analyzed using biochemical, molecular, and phenotypic methods. The total heterotrophic bacterial counts were recorded as 82.25 ± 4.7 CFU/mL × 10⁷ in Laundry Wastewater V and 94.50 ± 6.1 CFU/mL × 10⁷ in Laundry Wastewater W. Twenty-five bacterial isolates which include Staphylococcus aureus, Staphylococcus spp., Escherichia coli, and pseudomonas spp. were characterized. The most frequently isolated bacterium was Staphylococcus aureus [11/25 (44.0%)], followed by Escherichia coli [7/25 (28.0%)], Pseudomonas spp. [4/25 (16.0%)], and Staphylococcus spp. [3/25 (12.0%)]. Virulence factors such as DNase activity, lipase activity, and hemolytic activity were assessed. DNase activity was observed in 40% of the isolates, lipase activity in 52%, and hemolytic activity in 92%. Among Staphylococcus aureus isolates, DNase activity was 45.5%, lipase activity was 54.5%, and hemolytic activity was 100%. Similarly, hemolytic activity was prevalent in all Escherichia coli isolates (100%) and 75% of Pseudomonas spp. isolates. This study highlights the high prevalence of virulence factors in bacterial isolates from laundry wastewater and underscores its potential as a reservoir of pathogenic microorganisms. Untreated discharge of such wastewater poses serious public health and environmental risks. Therefore, it
emphasizes the need for enhanced wastewater treatment systems and further research on the
ecological and epidemiological implications of virulence factors in laundry effluents.

The potential public health risk associated with ready-to-eat (RTE) fruits sold in open markets was investigated through a microbiological assessment of three popular fruits: Apple, Pineapple, and Watermelon. A total of three samples were purchased from a market in Benin City and analyzed using standard microbiological techniques, including serial dilution, plating on selective media, and biochemical analysis. The mean total bacterial count was highest in Pineapple and lowest in Apple, while the mean total fungi count was highest in Apple and lowest in Watermelon. Bacterial isolates included Staphylococcus aureus, Bacillus spp, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter. Fungal isolates included Aspergillus niger, Yeasts, Penicillium species, and Mucor. Antibiotic susceptibility testing revealed isolates with resistance to multiple drugs, including Rocephin, Pefloxacin, and Ampliclox (for Gram-positive bacteria), while showing susceptibility to agents like Ciprofloxacin, Gentamicin, Levofloxacin, Ofloxacin, and Amoxicillin. The presence of these pathogenic and opportunistic micro-organisms confirms the contamination of the RTE fruits, which poses a significant public health hazard. This poor microbiological quality is likely due to unhygienic preparation environments, contaminated water, improper handling, and environmental exposure. Regulatory bodies must enhance surveillance, and vendors should strictly adhere to safe food handling practices. Consumers are advised to ensure proper washing of fruits before consumption.

This study focused on the isolation and identification of bacteria from environmental hot spots using dumpsites located within Oredo Local Government Area of Benin City, Edo State, Nigeria, as reference points. The investigation aimed to assess the bacterial load, identify predominant microbial species, and evaluate their antibiotic susceptibility patterns. Ten samples were collected from various dumpsite points and analyzed using standard microbiological procedures. Total heterotrophic bacterial counts (THBC) ranged from 5 × 10⁴ to 1.25 × 10⁶ CFU/mL on MacConkey and EMB agars, indicating high microbial activity and organic contamination. Four representative isolates were further characterized biochemically and identified as Escherichia coli (three isolates) and Pseudomonas spp. (one isolate). Antibiotic susceptibility testing using the disk diffusion method revealed that all isolates were highly sensitive to fluoroquinolones (ofloxacin, ciprofloxacin, peflacine) and aminoglycosides (gentamicin, streptomycin) but exhibited strong resistance to β-lactam antibiotics such as ceporex and cefuroxime. The dominance of E. coli reflects fecal contamination of the dumpsites, while the presence of Pseudomonas spp. highlights the persistence of environmental opportunistic pathogens. The results suggest that these dumpsites represent potential reservoirs of antibiotic-resistant bacteria with implications for public health and environmental safety. This study emphasizes the urgent need for improved waste management, microbial monitoring, and enforcement of environmental sanitation standards to mitigate the spread of antimicrobial resistance in Benin City and other urban areas of Nigeria.

This project focused on checking the microbiological quality of different snacks sold within the University of Benin campus. The study was carried out to find out if the snacks commonly eaten by students are safe and free from harmful microorganisms. Snacks such as meat pie, chicken pie, egg roll, fish roll, doughnut, and puff-puff were selected because these foods are among the most popular foods sold by vendors around the school. Samples were collected from various vending points across the university and analyzed using standard laboratory methods. The total number of bacteria and fungi present in each snack was determined, and the organisms were identified using gram staining and biochemical tests. Antibiotic sensitivity tests were also performed to know how the bacterial isolates responded to common antibiotics. The results showed that all the snacks contained microorganisms, but at different levels. Egg roll and meat pie had the highest bacterial counts, while puff-puff showed the lowest. Common bacteria found included Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis, while fungi such as Aspergillus niger and Candida albicans were also isolated. Some bacteria were resistant to certain antibiotics but remained sensitive to others. This study concludes that while most snacks sold within the University of Benin are within acceptable limits of microbial safety, the presence of some harmful microorganisms shows that hygiene during preparation and handling needs to be improved. Regular health checks for food handlers and proper hygiene education are strongly recommended to prevent foodborne infections among students.

The potential public health risk associated with ready-to-eat (RTE) fruits sold in open markets was investigated through a microbiological assessment of three popular fruits: Apple, Pineapple, and Watermelon. A total of three samples were purchased from a market in Benin City and analyzed using standard microbiological techniques, including serial dilution, plating on selective media, and biochemical analysis. The mean total bacterial count was highest in Pineapple and lowest in Apple, while the mean total fungi count was highest in Apple and lowest in Watermelon. Bacterial isolates included Staphylococcus aureus, Bacillus spp, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter. Fungal isolates included Aspergillus niger, Yeasts, Penicillium species, and Mucor. Antibiotic susceptibility testing revealed isolates with resistance to multiple drugs, including Rocephin, Pefloxacin, and Ampliclox (for Gram-positive bacteria), while showing susceptibility to agents like Ciprofloxacin, Gentamicin, Levofloxacin, Ofloxacin, and Amoxicillin. The presence of these pathogenic and opportunistic micro-organisms confirms the contamination of the RTE fruits, which poses a significant public health hazard. This poor microbiological quality is likely due to unhygienic preparation environments, contaminated water, improper handling, and environmental exposure. Regulatory bodies must enhance surveillance, and vendors should strictly adhere to safe food handling practices. Consumers are advised to ensure proper washing of fruits before consumption.

Background: Street-vended foods are a crucial and affordable source of nutrition for millions globally, particularly in developing urban areas. However, poor hygiene practices during preparation, handling, and storage pose significant public health risks. This study investigated the antibiotic resistance patterns and phenotypic virulence characteristics of bacterial pathogens isolated from various street-vended foods.Methods: A total of [Number, e.g., 150] street-vended food samples (including [list types of food, e.g., ready-to-eat meats, salads, rice dishes]) were randomly collected from [Location/City]. Bacterial isolation and identification were performed using standard microbiological and biochemical techniques. Antibiotic susceptibility testing was conducted using the Kirby-Bauer disc diffusion method against [Number] commonly prescribed antibiotics. Phenotypic virulence traits, including hemolysin production, biofilm formation, capsule production, and motility, were evaluated using specialized agar media and assays.Results: The predominant bacterial isolates identified were [e.g., Staphylococcus aureus, Escherichia coli, and Salmonella spp.]. Antibiotic susceptibility profiling revealed alarming rates of resistance, particularly toward [Name 1-2 antibiotics, e.g., ampicillin and tetracycline], with [Percentage]% of the isolates classified as multidrug-resistant (MDR). Phenotypic characterization demonstrated high virulence potential among the isolates: [Percentage]% exhibited $\beta$-hemolytic activity, [Percentage]% were proficient biofilm formers, and [Percentage]% demonstrated active motility. A strong correlation was observed between biofilm-forming capabilities and resistance to critical-line antibiotics. Conclusion: The findings underscore that street-vended foods in [Location] serve as major reservoirs for virulent, multidrug-resistant bacteria. The coexistence of high phenotypic virulence and extensive antibiotic resistance among these isolates presents a severe threat to consumer safety and public health. There is an urgent need for stricter enforcement of food safety regulations, routine microbiological surveillance, and comprehensive hygiene training for food vendors to mitigate the risk of foodborne outbreaks.

Food safety remains a critical public health concern globally, with dairy products repeatedly implicated in food-borne illness outbreaks. This study aimed to detect enteric pathogens in dairy products sold in Benin City, Edo State. Dairy product samples comprising of branded (Hollandia, Nana, Cedaa, and Super Yogo) and locally processed (Nono milk, Kindoromo, Wara, and Maishanu) products were purchased for this study. Enumeration and isolation of bacteria was done using serial dilution and pour plate techniques on selective agar. Bacterial isolates were identified based on cultural, morphological and biochemical characteristics. The pH and total titratable acidity of samples were determined using a pH meter and acid/base titration method respectively, while antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. The total heterotrophic bacteria count of the samples ranged from 4.8±0.26 to 8.6±0.26 ×10⁸ CFU/ml, while colony counts on MacConkey agar, Salmonella-Shigella agar, and Eosin methylene blue agar ranged from 0.80±0.485 to 6.67±1.53 ×10⁷ CFU/ml; 1.13±0.31 to 6.87±0.61 ×10⁴ CFU/ml and 5.07±0.64 to 7.0±0.40 ×10³ CFU/ml respectively. Six bacterial isolates were identified in this study, which include: Escherichia coli1 , Escherichia coli 2 , Salmonella sp.1 , Salmonella sp.2 , Enterobacter aerogenes and Serratia marcescens with Escherichia coli1 , Escherichia coli2 , Salmonella sp 1 and Salmonella sp 2. having the highest frequency of occurrence of 33.33% each. The pH values of dairy samples ranged from 3.82±0.01 to 6.96±0.03, while total titratable acidity ranged from 0.17±0.02 to 1.86±0.02 mg/l. Most isolates were resistant to antibiotics used, with resistance indices ranging from 0.1 to 0.8, with Enterobacter aerogenes and Salmonella sp.2 recording the highest resistance index of 0.8, indicating multidrug resistance pattern. This study revealed that dairy products (especially in locally processed dairy products) sold in Benin City showed the enteric bacteria which may possibly be pathogenic with high multidrug resistance profiles, underscoring the need for improved hygiene practices, enforcement of pasteurization standards, and stringent microbiological monitoring in the dairy value chain.

Street-vended foods provide affordable nutrition for many urban populations but often serve as vehicles for food-borne pathogens capable of causing systemic health effects. This study investigated the effects of pathogens isolated from street-vended foods on the hematological parameters and oxidative stress markers of Wistar rats. Bacteria isolated from street-vended foods were obtained for this study and identified using molecular (polymerase chain reaction) technique. Thereafter, isolates were screened for phenotypic virulence characteristics (biofilm formation, haemolysin and gelatinase production) using standard techniques. Twenty-five wistar rats weighing 169.40g-175.01g were used. Enumeration and isolation of feed samples was done using serial dilution and pour plate techniques. After one week acclimatization, rats were randomly selected into five equal groups (control, W1,W2, X1 and X 2). Rats were experimentally infected with different concentrations (0.06ml and 0.1ml) of Escherichia coli (PX395408) and
Klebsiella pneumoniae (PX395409). After infection, changes in the weight of rats were determined weekly. Following sacrifice, blood and tissue samples were obtained for hematology and histopathological examination. The results revealed that E. coli exhibited β-hemolytic activity, was positive for biofilm formation, and negative for gelatinase production, while K. pnuemoniae showed γ-hemolytic activity and was negative for both biofilm and gelatinase production. The total heterotrophic bacterial counts of feed samples ranged from 5.35±0.07 to 6.90±1.56×10⁵ cfu/g, with isolates including Citrobacter spp and Klebsiella spp. The initial body weight of rats ranged from 169.00 ± 13.90 g to 175.00 ± 10.40 g, while the control group weighed 170.61 ± 4.90 g. After infection, the control rats gained weight steadily (189.35 ± 12.52g), whereas infected rats showed weight reduction, ranging from 125.76 ± 11.95 g to 145.02 ± 28.94 g, indicating systemic infection. Hematological analysis revealed that the control rats maintained normal values except for slightly higher white blood cell counts compared to infected groups. Rats infected with E. coli (0.06 mL) recorded higher red blood cell (RBC) and hemoglobin (HGB) levels than the control, while platelet (PLT) counts significantly increased in K. pneumoniae-infected rats, particularly in the high-dose group (1315±546). Significant differences (p<0.05) were observed in mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values, while other parameters showed no significant differences (p>0.05). Oxidative stress markers revealed that K. pneumonia infected rats exhibited elevated superoxide dismutase (SOD) and malondialdehyde (MDA) levels, indicating oxidative damage, whereas catalase (CAT) and glutathione peroxidase (GPx) activities were significantly increased in all infected groups. These findings demonstrate that E. coli and K. pnuemoniae from street-vended foods can induce hematological alterations, oxidative stress, and weight loss in Wistar rats, underscoring the need for improved food hygiene and stricter safety regulations.

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 study was carried out to determine the antagonistic activity of Trichoderma viride and Bacillus sp. against microorganisms responsible for disease or spoilage of potato. Diseased/spoilt potato tubers were obtained from open markets in Benin City. Standard microbiological techniques were employed for isolation of bacteria and fungi from diseased/spoilt potato tubers. Bacteria and fungi were enumerated using pour plate method. Cultural, morphological and biochemical characteristics were employed for identification of the isolates. Pathogenicity tests were used to evaluate the involvement of the isolates in the spoilage or disease of potato tubers. Biocontrol or antagonistic activity was carried out for the spoilage-causing microbes which were Trichoderma viride and Bacillus sp. using Potato dextrose agar and Mueller Hinton agar. The results revealed that the heterotrophic bacterial counts for spoilt/diseased potato ranged from log10 3.65±0.41 cfu/g (Uselu market) to log10 4.02±0.25 cfu/g (Aduwawa Market), while the fungal counts ranged from log10 3.57±0.30 cfu/g (Aduwawa market) to log10 3.85±0.10 cfu/g (Uselu market). The cultural morphological and biochemical characteristics of bacterial isolates from spoilt potato revealed their identity as; Erwinia sp, Pseudomonas aeruginosa, Bacillus sp. and Staphylococcus aureus while the fungal isolates from spoilt potato were Aspergillus sp., Rhizopus sp. and Penicillium sp.. The pathogenicity or spoilage test of isolated microorganisms from spoilt to healthy potato tubers showed that only Erwinia sp. and Aspergillus sp. were found to induce disease or spoilage condition in potato tubers. The in vitro antagonism (percentage inhibition) of Bacillus sp. and Trichoderma viridia on growth of Aspergillus sp. and Erwinia sp. showed that Trichoderma viridia had more biocontrol effect on growth of Aspergillus (50%) and Erwinia (47%) after 5 days of culture on growth media. In conclusion, Trichoderma viride and Bacillus sp. exhibited significant antagonistic activity against potato soft rot pathogens. The study identifies Erwinia sp. and Aspergillus sp. as key contributors to potato spoilage. Trichoderma viride demonstrates a notable biocontrol effect, inhibiting the growth of Aspergillus sp. and Erwinia sp.. These findings reveals the potential of Trichoderma viride and Bacillus sp. as promising biocontrol agents for mitigating potato soft rot, offering sustainable and environmentally friendly alternatives for potato cultivation and storage.