Department of Biological Sciences

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Browsing Department of Biological Sciences by Author "Aemere Ogunlaja"

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    Pathogenic bacteria in air samples: an appraisal of the African studies versus other continents
    (Springer, 2025-11-25) Aemere Ogunlaja
    Pathogenic infections especially those caused by organisms resistant to antimicrobials pose a critical challenge to achieving Sustainable Devel- opment Goal 3 (SDG 3), particularly in Africa. The environment is also indicated as a significant vector for antimicrobial resistance (AMR) dissemination. Unfortunately, the air is the least monitored environ- ment or reported for AMR. This study reviews the prevalence of bacterial pathogens and resistomes in African air samples, comparing them with global reports. Using PubMed and Google Scholar, publica- tions from 2013 to 2023 on biomonitored air samples were reviewed; the regional gaps in this area across the African continent and between other continents are highlighted. West Afri- can region had the highest research output and pub- lications, predominantly from Nigeria (46.6%). Most of the African studies focused on indoor air environ- ments, especially in hospitals, employing passive air sampling. Staphylococcus aureus was the most fre- quently reported bacteria, with tetracycline resistance being the most common. Only three studies in Africa clearly reported antibiotic resistance genes (ARGs) in the air, a stark contrast to the numerous global studies employing molecular methods. The review highlights the lack of indigenous solutions for air treatment and underlines the need for improved surveillance, fund- ing, and policy enforcement to mitigate AMR and strengthen public health systems accurrence of bacteria, their antibiotic resistance profiles, and the knowledge
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    Pollution and risk assessment of phenolic compounds in drinking water sources from South‐Western Nigeria
    (2023-05-09) Aemere Ogunlaja
    This study reports the occurrence and risk assessment of 2,4-dinitrophenol (2,4-DNP), phenol (PHE), and 2,4,6-trichlorophenol (2,4,6-TCP) in drinking water sources in three south-western States in Nigeria (Osun, Oyo, and Lagos). Groundwater (GW) and surface water (SW) were collected during dry and rainy seasons of a year. The detection frequency of the phenolic compounds followed the trend Phenol > 2,4-DNP > 2,4,6-TCP. The mean concentrations of 2,4-DNP, Phenol, and 2,4,6-TCP in GW/SW samples from Osun State were 639/553 μg L−1, 261/262 μg L−1, and 169/131 μg L−1 during the rainy season and 154/7 μg L−1, 78/37 μg L−1, and 123/15 μg L−1 during the dry season, respectively. In Oyo State, the mean concentrations were 165/391 μg L−1 for 2,4-DNP and 71/231 μg L−1 for Phenol in GW/SW samples, respectively, during the rainy season. Generally, in the dry season, these values decreased. In any case, these concentrations are higher than those previously reported in water from other countries. The concentration of 2,4-DNP in water posed serious ecological risks to Daphnia on the acute scale while it was algae on the chronic scale. Estimated daily intake and hazard quotient calculations suggest that 2,4-DNP and 2,4,6-TCP in water pose serious toxicity concerns to humans. Additionally, the concentration of 2,4,6-TCP in water from Osun State in both seasons of the year and in both groundwater and surface water poses significant carcinogenic risks to persons ingesting water from these sources in the State. Every exposure group studied were at risk from ingesting these phenolic compounds in water. However, this risk decreased with increasing age of the exposure group. Results from the principal component analysis indicate that 2,4-DNP in water samples is from an anthropogenic source different from that for Phenol and 2,4,6-TCP. There is a strong need to treat water from GW and SW systems in these States before ingesting while assessing their quality regularly.
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    Risk assessment and photo-disinfection of antibiotic residues and antibiotic-resistant bacteria in water sources from Ede,avy Metals in Groundwater Sources from Two Rural Communities in Nigeria
    (2025-05-16) Aemere Ogunlaja
    Environmental antibiotic residues (EARs) and antibiotic-resistant bacteria (ARB) are known to contribute to global antimicrobial resistance (AMR). This study investigated EAR levels in selected wells, river, abattoir wastewater, bottled water and sachet water from Ede, Nigeria. Ecological risk quotient (RQ) and health risk (Hazard quotient) of the levels of these EARs, ARB and multidrug-resistant bacteria (MDR) with their antibiotic resistance were calculated. Antibiotic residues detected included tetracycline-TET (14.2–135.8 μg/L), chloramphenicol-CHL (6.8–224.7 μg/L), metronidazole-MET (3.7–83.8 μg/L), sulfamethoxazole-SUL (0.56–18.6 μg/ L), and ciprofloxacin-CIP (3.8–97 μg/L). Antibiotic residues in STW samples were below the detection limit while ampicillin was not detected in any of the water samples. Chloramphenicol posed the highest ecological risk to algae while infants were particularly at risks of ciprofloxacin and metronidazole resistance in various water sources. No health risk due to bottled water exposure is observed for any population group. The mean log10 bacteria count (cfu/mL) followed the trend abattoir (5.68) > river (5.67) > hand-dug well (5.53) > sachet (5.03) > bottled (4.83). The most occurring ARB in water samples are Bacillus spp (36.3 %) > Staphylococcus (27.5 %) and the most dominant MDR isolate is Bacillus cereus. All isolates exhibited 62.5, 100, 31.3, 77.5, 58.8 and 33.8 % resistance to AMP, MET, CIP, TET, CHL and SUL, respectively. Visible-light composite material (Cu/Zn-doped delaminated kaolinite) completely disinfected 12.5 and 15.8
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    Toxicity and removal of parabens from water: A critical review
    (Elsevier, 2021-05-24) Aemere Ogunlaja
    Parabens are biocides used as preservatives in food, cosmetics and pharmaceuticals. They possess antibacterial and antifungal activity due to their ability to disrupt cell membrane and intracellular proteins, and cause changes in enzymatic activity of microbial cells. Water, one of our most valuable natural resource, has become a huge reservoir for parabens. Halogenated parabens which are a result of chlorination/ozonation of water contaminated with parabens have shown to be even more persistent in water than other types of parabens. Unfortunately, there is dearth of data on their presence and fate in groundwater which serves as a major source of drinking water for a huge population in developing countries. An attempt to neglect the presence of parabens in water will expose man to it through contaminated food and direct ingestion of contaminated water. Although there are reviews on the occurrence, fate and behaviour of parabens in the environment, they largely omit toxicity and removal aspects. This review therefore, presents recent reports on the acute and chronic toxicity of parabens, their estrogenic ago- nistic and antagonistic activity and also their relationship with antimicrobial resistance. This article further X-rays several techniques that have been employed for the removal of parabens in water and their drawbacks including adsorption, biodegradation, membrane technology and advanced oxidation processes (AOPs). The heterogeneous photocatalytic process (one of the AOPs) appears to be more favoured for removal of parabens due to its ability to mineralize parabens in water. However, more work is needed to improve this ability of heterogeneous photo- catalysts. Perspectives that will be relevant for future scientific studies and which will drive policy shift towards the presence of parabens in our drinking waters are also offered. It is hoped that this review will elicit some spontaneous actions from water professionals, scientists and policy makers alike that will provide more data and effective technologies that will address the growing threat of the presence of parabens in our environment with respect to human health.