Effect of physical stresses on survivability and post-exposure antibiotic susceptibility of coliforms in environmental waters and wastewaters

Background: Coliform bacteria are majorly introduced into water bodies (river and wastewater) as a result of faecal pollution, agricultural run-offs and several anthropogenic activities. Despite the effectiveness of water treatment methods, pathogens still persist in water; hence the relevance of assessing the ability of these pathogens to survive the lethal actions of physical stresses and the possible impact on antibiotic susceptibility pattern of the organisms.Methodology: The survivability of Escherichia coli strains (NCM3722, FAP1 and ST2747), Enterobacter cloacae GGT036 and Shigella sonnei 53G was assessed in environmental and waste waters for 21 days. The effect of three treatment regimens (UV radiation, solar radiation and boiling) on the survival of the coliforms was evaluated. Also, the antibiogram of the isolates post–UV exposure was assayed.Results: Although there was significant reduction (≥ 3-log) in the population of the bacteria overtime, all the coliforms survived in the waters for 21 days. The effect of UV radiation was significant on all organisms (> 3 log reductions). Solar radiation for 60 minutes had significantly lesser effect than boiling for 15 minutes. Surviving cells of all isolates demonstrated multiple drug-resistance post exposure to UV radiation.Conclusion: This study revealed the ability of coliforms to persist in waters after treatment and proves that UV radiation may not be effective in attenuation of antibiotic resistance.Keywords: Survivability; Coliforms; Antibiotic susceptibility; Water; Wastewate

STUDIES ON THE EFFICACY OF BRIDELIA FERRUGINEA BENTH BARK EXTRACT FOR DOMESTIC WASTEWATER TREATMENT

The efficacy of Bridelia ferruginea Benth bark extract in wastewater treatment was investigated. Chemical analysis found the bark to contain potassium, sodium, calcium, magnesium, zinc, manganese, iron and copper. Phytochemical tests revealed the bark to contain tannins, phlobatannins, saponins, alkaloids, and steroids. Comparative studies using varying concentrations (0.5, 1.0, 2.5 and 5.0 % w/v) with alum and ferric chloride showed that the bark extract was effective in the clarification and sedimentation of total solids in the waste water sample. The optimum dose achieved was 2.5 % w/v with a minimum of 24 hours contact time. The total bacteria counts were reduced by 46 % after 24 hours when the extract was used whereas ferric chloride achieved 50 % reduction and alum achieved 55 % reduction under similar conditions. The feasibility of using the bark extract as an additional coagulant is therefore discussed. KEYWORDS: Bridelia ferruginea, Sedimentation, Total bacteria count, Wastewater treatment Bull. Chem. Soc. Ethiop. 2007, 21(2), 205-211

Biodegradative activities of some gram- negative bacilli isolated from kerosene treated soil grown with cowpea (Vigna unguiculata)

The biodegradative activities of three Gram negative bacilli (Aeromonas hydrophila, Vibro parahaemolyticus and Actinobacillus sp) isolated from soil contaminated with kerosene and planted with cowpea was investigated. The isolates were identified using MicrobactTM ID 24E system for the identification of Enterobacteriaceae and common miscellaneous Gram negative bacilli (MGNB). 2kg of soil collected from University of Ilorin was placed inside transparent, drilled buckets. Physicochemical properties of the soil were recorded. The soil was contaminated with kerosene at different concentrations of 0ml, 7ml, 14ml, 21ml, 56ml, 112ml, 168ml and 224ml. The setup was laid out in a randomized complete block design with three replicates. Cowpea seeds of the variety Samaru-40 were cultivated and observed for eight weeks. The results indicated that kerosene contamination of soils significantly affected the growth parameters: germination percentage, time of germination, rate of germination, plant height, number of leaves, leaf area and root nodules. A negative interaction existed between the level of the contaminant and the growth characteristics measured. Their biodegradative activities were studied and confirmed by the change in the Total Petroleum Hydrocarbon (TPH) using gravimetric method. The biodegradative abilities of the isolates were compared by measuring the optical densities, total viable count, pH and emulsification activity. The results showed that the organisms did better as a consortium rather than singly. Aeromonas hydrophila had the highest biodegradative activity followed by Vibro parahaemolyticus and then Actinobacillus sp. The study recommends the use of Aeromonas hydrophila and consortium for more effective biodegradation.Keywords: Bacterial Biodegradation, Soil, Cowpea, Kerosene, Total Petroleum Hydrocarbo

Effects of cooking oils and packaging media on quality of meat floss

Meat floss (MF) is one of the popular ready-to-eat meat products among the elites of northern Nigeria, which is fast extending to some other parts of the country because of its long shelflife at room temperature. Nonetheless, there is little documentation on the keeping quality during storage when MF is prepared from different cooking oil and packaged in different materials. In this study, meat floss was produced from raw beef (3kg) by cooking, cooling, shredding and deep frying. The deep frying was done in three cooking oils (groundnut oil - GO, soya oil - SO and palm oil - PO) and the products were packed in three materials (acrylic bottle - P1, polyethylene - P2 and polyamide - P3 ). The frying was done using 1 litre each oil to 500 g of shredded meat, continued until golden brown colour was reached at about 20 minutes. The iodine number of each of the three oil types, and the crude protein and moisture contents of the raw meat and freshly prepared meat floss were determined. At 7, 14 and 21 days of storage the meat floss types were assessed for microbial growth and Thiobarbituric Acid Reactive Substances (TBARS). The study was a 3 x 3 factorial experiment fitted into completely randomized design replicated three times. The GO had highest iodine number (38.83) and PO had the least (28.00). The protein content of MF (43.93%) was higher than that of raw meat (21.79%). The MFSO was richest in crude protein (44.54%) but MFPO had highest moisture content (14.33%). The microbial load (1.49 log10-2cfu/cm2) and TBARS (0.82mg MDA/kg) of fresh MFSO was highest. The microbial load decreased with storage, with highest values obtained in MFSO on 0, 7 and 14 days. However on day 21, the three MF types had similar lowest microbial load. The polyamide pack had the highest microbial load throughout the storage period. Conversely, the TBARS of MF prepared from the three oils and stored in the three materials increased with storage for 21 days, with highest values obtained in MFSO and in polyamide. Nonetheless, all values obtained for microbial load and TBARS during storage did not exceed the threshold values for spoilage of stored meat products. It can be inferred from the study that though meat floss produced from palm oil and packed in acrylic bottle stored best, any of the three oils and any of the three packaging media retained the keeping quality of beef meat floss for 21 days at room temperature.Keywords: Cooking oils, lipid oxidation, meat floss, microbial growth, packaging medi

AETIOLOGIC AGENTS OF DIARRHOEA IN CHILDREN UNDER FIVE YEARS OF AGE IN OSOGBO, OSUN STATE

A survey of the aetiological agents of diarrhoea in children under 5 years of age was carried out in Osogbo, Osun State. A total of 135 patients visiting the outpatient and children emergency units of LAUTECH Teaching Hospital were examined. Strains of Shigella isolated were tested for antibiotic sensitivity. Consideration of the distribution showed that Escherichia coli was more prevalent in children aged between 3 to 5 years (57%) and was the most encountered of the organisms isolated (present in 77.8% of all samples) while Shigella spp was found in 16.3% of samples, Vibrio cholerae 0.7% and other coliforms 5.2%. Statistical analysis showed that E. coli was significantly associated with diarrhoea in the patients aged 3-5 years (P< 0.05). Shigella spp was shown to show some resistance to tetracycline and high sensitivity to ofloxacin. (Af J Clinical & Exp Microbiology: 2003 4(2): 62-66

<b>Studies on the efficacy of <i>Bridelia ferruginea</i> Benth bark extract for domestic wastewater treatment</b>

The efficacy of <i>Bridelia ferruginea</i> Benth bark extract in wastewater treatment was investigated. Chemical analysis found the bark to contain potassium, sodium, calcium, magnesium, zinc, manganese, iron and copper. Phytochemical tests revealed the bark to contain tannins, phlobatannins, saponins, alkaloids, and steroids. Comparative studies using varying concentrations (0.5, 1.0, 2.5 and 5.0 % w/v) with alum and ferric chloride showed that the bark extract was effective in the clarification and sedimentation of total solids in the waste water sample. The optimum dose achieved was 2.5 % w/v with a minimum of 24 hours contact time. The total bacteria counts were reduced by 46 % after 24 hours when the extract was used whereas ferric chloride achieved 50 % reduction and alum achieved 55 % reduction under similar conditions. The feasibility of using the bark extract as an additional coagulant is therefore discussed