DEPARTMENT OF MICROBIOLOGY

Airborne bacterial contamination in student residential areas poses significant public health risks, particularly in densely populated university settings. This study evaluated the microbial quality of air in two student hostels, Ekosodin and Osasogie, at the University of Benin, Edo State, Nigeria, over a three-week period. Air samples were collected and analyzed for total bacterial counts, cultural and biochemical characteristics, distribution patterns, frequency of occurrence, and antibiotic susceptibility profiles. The results revealed that Ekosodin generally exhibited higher bacterial loads, peaking at 5.4 ± 0.35 ×10³ CFU/m³ during Week 2, whereas Osasogie recorded the lowest load of 2.1 ± 0.20 ×10³ CFU/m³ in Week 3. Six bacterial species were isolated: Staphylococcus aureus, Escherichia coli, Klebsiella sp., Proteus sp., Pseudomonas aeruginosa and Bacillus sp. E. coli (25%) and S. aureus (20%) were the most frequently occurring isolates. Antibiotic susceptibility testing revealed that fluoroquinolones (ciprofloxacin and pefloxacin) and aminoglycosides (gentamicin and streptomycin) were the most effective against the isolates, while beta-lactams (ampicillin and amoxicillin) and cotrimoxazole showed widespread resistance. The Multiple Antibiotic Resistance (MAR) indices ranged from 0.00 (Bacillus sp.) to 0.40 (Pseudomonas aeruginosa), highlighting the presence of multidrugresistant bacteria in the residential air. These findings underscore the need for improved ventilation, hygiene, and routine microbial monitoring in student residential facilities to mitigate the risks of airborne bacterial infections.

The growing resistance of pathogenic bacteria to commonly used antibiotics has stimulated renewed global interest in medicinal plants as alternative sources of antimicrobial agents. One such plant, Ocimum gratissimum (commonly known as scent leaf), has long been utilized in traditional medicine due to its therapeutic properties. This study investigated the antibacterial activity of scent leaf extracts against selected bacterial pathogens. Fresh leaves of Ocimum gratissimum were procured, air-dried, and ground into powder. The powdered material was extracted using ethanol and distilled water to obtain ethanolic and aqueous extracts, respectively. The antibacterial effects of these extracts were evaluated against clinical isolates of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, obtained from the University of Benin Teaching Hospital, using the agar well diffusion technique in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Phytochemical analysis of both extracts confirmed the presence of alkaloids, flavonoids, tannins, and saponins in varying concentrations, with the ethanolic extract exhibiting a higher abundance of these bioactive compounds. Antibacterial testing revealed a concentration-dependent inhibitory effect for both extracts, with reduced activity observed at lower concentrations. However, the ethanolic extract demonstrated superior antibacterial efficacy, producing inhibition zones of up to 15 mm against Staphylococcus aureus and 12 mm against Pseudomonas species at a concentration of 100 mg/mL. In contrast, the aqueous extract showed moderate activity, with inhibition zones ranging between 10 mm and 12 mm. The minimum inhibitory concentration (MIC) of the ethanolic extract was determined to be 50 mg/mL for S. aureus, E. coli, and Pseudomonas, while Klebsiella species required 100 mg/mL for inhibition. For the aqueous extract, MIC values were only observed at 100 mg/mL for E. coli and Pseudomonas. Furthermore, the minimum bactericidal concentration (MBC) of the ethanolic extract was 50 mg/mL for Staphylococcus aureus and Pseudomonas, and 100 mg/mL for E. coli, whereas Klebsiella species exhibited only bacteriostatic response. The aqueous extract showed bactericidal activity only against Pseudomonas at 100 mg/mL. Overall, the results indicate that Ocimum gratissimum possesses notable antibacterial properties, particularly when extracted with ethanol. These findings validate its traditional medicinal use and suggest its potential application in the development of plant-based antimicrobial agents.

Door handles in public spaces serve as potential reservoirs for microbial contamination, posing risks for the transmission of pathogenic bacteria. This study aimed to isolate, identify, and assess the antibiotic susceptibility of bacterial contaminants on door handles of selected banks within the University of Benin, Benin City, Edo State, Nigeria. The research was conducted across five banks within the university campus, selected due to their high patronage, which increases the likelihood of microbial contamination. Sterile swab samples were collected from both entrance and interior door handles of each bank over a two-week period, during peak business hours (10:00 AM – 12:00 PM). The collected swabs were transferred into sterile peptone water and transported to the microbiology laboratory within one hour for bacterial analysis. The total heterotrophic bacterial count (THBC) was determined using standard culture techniques, with counts ranging from 2.03 ± 0.03 × 10⁴ CFU/ml (Bank D) to 4.72 ± 0.31 × 10⁴ CFU/ml (Bank E). Biochemical and morphological characterization of isolates identified seven bacterial species, including Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas sp., Enterobacter sp., Escherichia coli, and Klebsiella sp. The frequency of occurrence varied, with Escherichia coli having the highest prevalence (28%), followed by Staphylococcus sp. (20%), while Pseudomonas sp. had the lowest occurrence (12%). Antibiotic susceptibility testing against ten commonly used antibiotics revealed varying resistance patterns among isolates. The multiple antibiotic resistance (MAR) index ranged from 0.3 to 0.5, with the highest recorded for Escherichia coli, Pseudomonas sp., and Micrococcus sp. The results highlight significant bacterial contamination on frequently touched surfaces, emphasizing the need for regular disinfection and improved hygiene practices in high-contact public spaces.

Lemongrass (Cymbopogon citratus) is widely known for its medicinal and antimicrobial properties, with its extracts being used in traditional and modern medicine. Due to the increasing resistance of bacteria to conventional antibiotics, plant-based antimicrobials have gained attention as alternative therapeutic agents. This study investigated the phytochemical composition and antibacterial activity of hot and cold water extracts of Lemongrass leaves against Staphylococcus aureus, Escherichia coli, and Pseudomonas sp. Phytochemical analysis revealed the presence of flavonoids, tannins, and glycosides in both extracts, with glycosides being more prominent in the hot extract. Saponins, steroids, and terpenoids were absent. Antibacterial activity was assessed using the agar well diffusion method, where the hot extract showed higher zones of inhibition at 100% concentration: S. aureus (13.00 ± 0.00 mm), E. coli (16.00 ± 0.00 mm), and Pseudomonas sp. (18.20 ± 0.00 mm), compared to the cold extract: S. aureus (9.0 ± 0.50 mm), E. coli (11.20 ± 0.20 mm), and Pseudomonas sp. (12.00 ± 0.00 mm). The Minimum Inhibitory Concentration (MIC) revealed that the hot extract inhibited E. coli at 25 mg/ml, Pseudomonas sp. at 50 mg/ml, and S. aureus at 25 mg/ml, while the cold extract only inhibited Pseudomonas sp. at 100 mg/ml and S. aureus at 25 mg/ml. Minimum Bactericidal Concentration (MBC) results showed that the hot extract was bactericidal against S. aureus and bacteriostatic against E. coli and Pseudomonas sp., while the cold extract was bactericidal against Pseudomonas sp. and bacteriostatic against the other isolates. Antibiotic susceptibility testing indicated that Gram-positive bacteria were highly susceptible to ciprofloxacin, while Gram-negative bacteria were sensitive to azithromycin. These results highlight the potential application of Cymbopogon citratus as an alternative treatment for bacterial infections, particularly in combating antibiotic-resistant pathogens

The consumption of ready-to-eat vended fruits has become increasingly popular in urban areas, particularly in developing countries. These fruits, often sold by street vendors, are convenient and accessible, providing a quick source of nutrition for many consumers. However, this convenience comes with significant health risks due to potential microbial contamination. Fresh fruits are rich in essential nutrients, including vitamins, minerals, and phytochemicals, making them an integral part of a balanced diet. Fruits can become contaminated with pathogenic microorganisms at various stages, including during harvesting, processing, and selling. Common sources of contamination include unsanitary water used for washing, improper handling by vendors, and exposure to environmental contaminants. Research has identified several bacterial pathogens associated with vended fruits, including Escherichia coli, Salmonella spp., Shigella spp., and Staphylococcus aureus. These pathogens pose a significant risk of foodborne illnesses, which can lead to severe gastrointestinal diseases in consumers. In Nigeria, the rising trend of consuming ready-to-eat fruits has been noted, particularly in markets where hygiene standards are often overlooked. The primary issue is the high prevalence of pathogenic microorganisms such as Escherichia coli, Salmonella spp., Shigella spp., and Staphylococcus aureus on these fruits. These pathogens can easily contaminate fruits through contact with sewage, contaminated utensils, and water, increasing the risk of foodborne illnesses among consumers. The presence of these microbial contaminants not only compromises the safety of ready-to-eat vended fruits but also poses a significant public health risk. The high bacterial and fungal loads observed in these fruits suggest that they are unfit for human consumption, necessitating urgent intervention to improve hygiene standards and food safety practices among vendors. The microbial contamination of ready-to-eat vended fruits is a significant concern. Studies have shown that these fruits can harbour a variety of microorganisms due to exposure to soil, dust, water, and mishandling during harvest and post-harvest processing. The microbial load in the vended fruits was assessed by determining the colony-forming units (CFU) per gram of fruit. The results indicate varying levels of microbial contamination across different fruits. The findings from this study reveal significant microbial contamination in ready-to-eat vended fruits from Ekosodin Community and the environs of the University of Benin. The results indicate a high microbial load across all fruit samples, with both bacterial and fungal contaminants identified. The presence of these bacteria and fungi suggests potential health risks, as they can cause foodborne illnesses if consumed

The scalp hair is composed of soft tissue layers that cover the cranium. This study focused on isolation, identification and antibiogram of bacteria isolates from scalp hair. With the aid of a sterile swab sticks, nine scalp hair of undergraduates’ students were swabbed and transported to the laboratory for bacteriological analysis. All the samples were analyzed within 24hrs of collection. Collected swabbed stick was submerged in a sterile test tubes label A – I contained Nutrient broth and incubated for 2hrs. 1ml was plated from each test tube. It was then incubated at 37 0 C for 24hours. The result of the bacteria isolated include; Staphylococcus epidermis 6 (15%), Staphylococcus aureus 6 (15%), Pseudomonas sp. 2(5%), Bacillus sp. 18(45%), Streptococcus spp. 5(12.5%) and Micrococcus spp. 3(7.5%). Haemolysin test on the strains of Staphylococcus auraeus Streptococcus sp. Staphylococcus epidermis, Micrococcus spp. and Psuedomonas sp. revealed they had β hemolytic activity and only strains of Bacillus spp. showed α hemolytic activity. While the gelatin test showed that all isolates produce gelatinase enzyme which breakdown gelatin. The antibiogram results revealed that All isolates were highly sensitive to ciprofloxacin, Ofloxacin and clindamycin 40(100%). Ciprofloxacin, Ofloxacin and clindamycin was proved to be the most effective against Gram positive and Gram-negative isolates studied in this work. Contamination of scalp hair from this research, could be from poor hand hygiene and environmental hygiene.

Lemongrass (Cymbopogon citratus) is widely known for its medicinal and antimicrobial properties, with its extracts being used in traditional and modern medicine. Due to the increasing resistance of bacteria to conventional antibiotics, plant-based antimicrobials have gained attention as alternative therapeutic agents. This study investigated the phytochemical composition and antibacterial activity of hot and cold water extracts of Lemongrass leaves against Staphylococcus aureus, Escherichia coli, and Pseudomonas sp. Phytochemical analysis revealed the presence of flavonoids, tannins, and glycosides in both extracts, with glycosides being more prominent in the hot extract. Saponins, steroids, and terpenoids were absent. Antibacterial activity was assessed using the agar well diffusion method, where the hot extract showed higher zones of inhibition at 100% concentration: S. aureus (13.00 ± 0.00 mm), E. coli (16.00 ± 0.00 mm), and Pseudomonas sp. (18.20 ± 0.00 mm), compared to the cold extract: S. aureus (9.0 ± 0.50 mm), E. coli (11.20 ± 0.20 mm), and Pseudomonas sp. (12.00 ± 0.00 mm). The Minimum Inhibitory Concentration (MIC) revealed that the hot extract inhibited E. coli at 25 mg/ml, Pseudomonas sp. at 50 mg/ml, and S. aureus at 25 mg/ml, while the cold extract only inhibited Pseudomonas sp. at 100 mg/ml and S. aureus at 25 mg/ml. Minimum Bactericidal Concentration (MBC) results showed that the hot extract was bactericidal against S. aureus and bacteriostatic against E. coli and Pseudomonas sp., while the cold extract was bactericidal against Pseudomonas sp. and bacteriostatic against the other isolates. Antibiotic susceptibility testing indicated that Gram-positive bacteria were highly susceptible to ciprofloxacin, while Gram-negative bacteria were sensitive to azithromycin. These results highlight the potential application of Cymbopogon citratus as an alternative treatment for bacterial infections, particularly in combating antibiotic-resistant pathogens.

The global rise of antimicrobial resistance (AMR) is a critical health crisis, making oncetreatable infections dangerous again. This problem is particularly severe in hospital settings, where the frequent use of antibiotics and the concentration of sick patients create an ideal environment for drug-resistant bacteria to spread. The aim of this study is to determine the antimicrobial resistance patterns of Staphylococcus aureus isolated from hospital-acquired infections in children at a tertiary hospital in Benin City. Using a cross-sectional design, clinical samples from 67 pediatric patients were analyzed for Staphylococcus aureus isolation, susceptibility testing via Kirby-Bauer method, and MRSA detection with cefoxitin. Staphylococcus aureus was the predominant pathogen (50% of isolates), with 53.1% multidrugresistant and 30.4% MRSA; high resistance noted to erythromycin (70%) and amikacin (73.1%), but full susceptibility to meropenem and piperacillin; male predominance (67.2%) and older adolescents as largest group (33.3%).These findings highlight alarming AMR levels in pediatric HAIs, aligning with SSA trends and underscoring gaps in empirical therapy. Urgent stewardship and surveillance are needed to curb resistance and improve outcomes.

The increasing prevalence of antibiotic-resistant bacteria has heightened the interest in medicinal plants as potential sources of bioactive compounds. This study evaluated the phytochemical composition, antioxidant potential, and antibacterial activity of ethanol leaf extracts of Jatropha tanjorensis (commonly known as Hospital-too-far) against selected clinical bacterial isolates. Leaves of J. tanjorensis were collected from the University of Benin Botanical Garden and authenticated in the herbarium of the Department of Plant Biology and Biotechnology. Clinical isolates of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli were obtained from the University of Benin Teaching Hospital. Qualitative phytochemical analysis revealed the presence of phenols, flavonoids, and alkaloids in high concentrations, while tannins and saponins were present at lower levels. Quantitative analysis showed phenols as the most abundant compound (129.31 µg/ml), followed by tannins (100.57 µg/ml), flavonoids (46.97 µg/ml), alkaloids (9.33%), and saponins (3.17%). Antioxidant evaluation demonstrated significant activity, with Total Antioxidant Capacity (TAC) of 219.08 µg/ml and Ferric Reducing Antioxidant Potential (FRAP) of 2607.27 µM. The extract also exhibited dose-dependent DPPH radical scavenging activity, with 48.97% inhibition at 10 µg/ml and 69.60% at 100 µg/ml. Antibacterial assessment revealed broad-spectrum activity, with Klebsiella pneumoniae being most susceptible (zone of inhibition: 18 mm at 30 µg/ml), while Escherichia coli and S. aureus showed moderate inhibition. The Minimum Inhibitory Concentration (MIC) ranged from 20–30 µg/ml, indicating bacteriostatic effects at lower concentrations and bactericidal activity at higher doses. Antibiotic susceptibility testing of the isolates confirmed high resistance to commonly used antibiotics, emphasizing the therapeutic potential of the plant extract. Overall, Jatropha tanjorensis leaves contain bioactive compounds with potent antioxidant and antibacterial properties, supporting its traditional use and potential application in combating resistant bacterial infections.

Medicinal plants have long been recognized for their therapeutic properties and remain an essential source of bioactive compounds with potential antimicrobial activity. The growing problem of antibiotic resistance has heightened global interest in exploring natural plant extracts as alternative or complementary agents against infectious diseases. This study evaluated the phytochemical composition and antimicrobial potential of lemongrass (Cymbopogon citratus) and uziza leaf (Piper guineense) extracts against selected bacterial and fungal pathogens. Fresh leaves of both plants were collected from local markets in Benin City, Edo State, Nigeria, authenticated, air-dried, pulverized, and extracted using ethanol and water. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, terpenoids, and saponins in varying concentrations. Lemongrass contained high levels of alkaloid, flavonoids and tannins, while uziza exhibited moderate presence of these compounds. Saponin was present in lemongrass but absent in uziza. Antimicrobial testing showed that ethanolic extracts demonstrated superior activity compared to aqueous extracts. The ethanolic extract of lemongrass exhibited the highest inhibition zone of 20 mm against S. aureus and 15 mm against E. coli at 100% concentration, while the uziza ethanolic extract produced inhibition zones of 18 mm and 15 mm, respectively, against the same organisms. Pseudomonas sp. showed moderate sensitivity with inhibition zones of 12 mm, whereas fungal isolates Aspergillus sp., Penicillium sp. and Fusarium sp. recorded inhibition zones ranging from 10 to 15 mm. The minimum inhibitory concentration (MIC) for ethanolic extracts ranged from 50 mg/mL for S. aureus, E. coli and Pseudomonas sp. to 100 mg/mL (for fungal isolates), while minimum bactericidal concentrations (MBCs) were observed at 100 mg/mL. Aqueous extracts displayed weaker activity, requiring higher concentrations (100 mg/mL) for inhibition and showing little or no effect on fungal isolates. Overall, these findings highlight the significant antimicrobial potential of lemongrass and uziza leaf extracts, particularly their ethanolic forms, which exhibited notable inhibitory effects against common bacterial pathogens. The results support their traditional medicinal use and underscore their potential as natural sources of plant-based antimicrobial agents.