Microbial assessment of the armpits of some selected university students in Lagos, Nigeria

A study of the carriage of microorganisms in armpits and prevailing factors was carried out on 80 students of the University of Lagos. The armpits were swabbed and the microbiological analyses were carried out on the swab samples. The organisms isolated include Staphylococcus epidermidis (35%), Staphylococcus aureus (3%), Staphylococcus cohnii (3%), Staphylococus haemolyticus (15%), Staphylococcus hominis (25%),Micrococcus luteus (9%), Staphylococcus capitis (6%), Staphylococcus saprophyticus (3%) and Candida tropicalis (1%). Questionnaires on gender and health related factors were administered to the subjects. Moststudents regardless of sex, used toilet soap (62.5%), had their bath twice daily (60%), used sponge for body scrubbing (87.5%) and shaved regularly (78.75%) but these did not have any significant influence on thecarriage of microorganisms (P = 0.05). More female participants used deodorants, than the males. The bacterial and fungal counts in the armpits of females were lower than the counts from male armpits, which means that the use of deodorant reduced the carriage of microorganisms. From the antibiotic sensitivity tests carried out on S. aureus, the highest sensitivity was recorded for Ofloxacin while the least was for  Cotrimoxazole. However the bacterium was resistant to most antibiotics tested. The DNA profile of S. aureus showed that none of the strains had a plasmid thereby suggesting that the antibiotic resistance genes in these strains could be chromosomally-encoded.Keywords: Microorganisms, armpit, university students, Lagos, Nigeria

Microbial population changes in tropical agricultural soil experimentally contaminated with crude petroleum

Impacts of crude petroleum pollution on the soil environment and microbial population dynamics as well as recovery rates of an abandoned farmland was monitored for seven months spanning the twomajor seasons in Nigeria with a view to establishing process conditions necessary for development of effective strategies for bioremediation. The physico-chemistry of the control and contaminated soilsdiffered just significantly (P < 0.05). Whereas these factors were relatively stable over the period of investigation for the control site, a downward trend was observed for the experimental. The pollutedsoil showed significant diversity in structure and number of flora .There was an initial drop in microbial population densities at the onset of pollution but, a gradual increase was observed thereafter. Highercounts of microflora were obtained for April, May, June and July samples which coincided with the onset and peak of wet season. A rapid and significant reduction in residual oil concentration wasobserved during this period. Overall, nearly 100% of the crude oil pollutant was degraded within the 28-week study period. The residual oil concentration gave a high but negative correlation coefficient (r = -0.84 to -0.90) with total heterotrophic and hydrocarbon-utilizing populations. On application of data generated to model equations, approximately 60.5 weeks would elapse before the contaminated soilcould recover from the impact of the oil. Our results show that a natural population readily able to degrade crude oil is present in the soil chosen for this study. However, it may be necessary to monitor the level of inorganic nutrients and adjust some appropriately to enhance biodegradation of the organic pollutant

Crude Oil-Degradation and Plasmid Profile of Nitrifying Bacteria Isolated from Oil-Impacted Mangrove Sediment in the Niger Delta of Nigeria

The crude oil degradability and plasmid profile of autotrophic nitrifying bacteria, Nitrosomonas and Nitrobacter species, isolated from mangrove sediment in the Niger Delta of Nigeria were studied. The effects of temperature, pH and optical density on the utilization of different carbon sources by the bacteria were also investigated. Results showed that nitrifying bacteria could utilize kerosene, diesel oil, jet fuel and engine oil as carbon sources. None utilized hexane and xylene but moderate growth was observed in benzene, phenol and toluene. However, their ability to utilized crude oil varied both in rates of utilization and in growth profiles. Mixed culture of the isolates degrades 52 % of crude oil introduced into the medium followed by Nitrosomonas sp. with 40 % degradation. The least was Nitrobacter sp. with 20 % degradation. The ability of the autotrophs to degrade crude oil was found to be plasmid-mediated through curing experiment and electrophoresis. The size of the plasmid involved was estimated to be 23 kb. The high crude oil utilization of the mixed culture implies that nitrifying bacteria isolated from contaminated ecosystem are excellent crude oil degraders and can be harnessed for bioremediation purposes

Microbial Community Analysis of a Coastal Salt Marsh Affected by the Deepwater Horizon Oil Spill

Conceived and designed the experiments: MJB RJM BM PAS. Performed the experiments: MJB RJM SR JP YMP LMT JDVN. Analyzed the data: MJB RJM YMP LMT GLA TCH JDVN JZ PAS. Contributed reagents/materials/analysis tools: GLA TCH JZ BM PAS. Wrote the paper: MJB RJM PAS.Coastal salt marshes are highly sensitive wetland ecosystems that can sustain long-term impacts from anthropogenic events such as oil spills. In this study, we examined the microbial communities of a Gulf of Mexico coastal salt marsh during and after the influx of petroleum hydrocarbons following the Deepwater Horizon oil spill. Total hydrocarbon concentrations in salt marsh sediments were highest in June and July 2010 and decreased in September 2010. Coupled PhyloChip and GeoChip microarray analyses demonstrated that the microbial community structure and function of the extant salt marsh hydrocarbon-degrading microbial populations changed significantly during the study. The relative richness and abundance of phyla containing previously described hydrocarbon-degrading bacteria (Proteobacteria, Bacteroidetes, and Actinobacteria) increased in hydrocarbon-contaminated sediments and then decreased once hydrocarbons were below detection. Firmicutes, however, continued to increase in relative richness and abundance after hydrocarbon concentrations were below detection. Functional genes involved in hydrocarbon degradation were enriched in hydrocarbon-contaminated sediments then declined significantly (p<0.05) once hydrocarbon concentrations decreased. A greater decrease in hydrocarbon concentrations among marsh grass sediments compared to inlet sediments (lacking marsh grass) suggests that the marsh rhizosphere microbial communities could also be contributing to hydrocarbon degradation. The results of this study provide a comprehensive view of microbial community structural and functional dynamics within perturbed salt marsh ecosystems.Yeshttp://www.plosone.org/static/editorial#pee

Degradation of aviation fuel by microorganisms isolated from tropical polluted soils

The degradation of aviation fuel was observed in soil samples from a polluted site at the aviation fuel depot, Lagos Airport, Nigeria. The percentage of occurrence of bacterial aviation fuel&ndash;utilizers were less than1.0% of the heterotrophic populations, while the fungal-degraders were between 2.547-16.053%. There were no significant statistical differences for both the bacteria and fungi estimations among the soil samples.Enrichment of soil samples with aviation fuel resulted in the isolation of five bacteria (Pseudomonas aeruginosa, Micrococcus luteus, Corynebacterium sp., Flavobacterium rigense, Bacillus subtilis), three yeasts (Rhodotorula sp., Candida tropicalis, Saccharomyces sp.) and two molds (Aspergillus niger, Penicillium sp.). Utilization of the substrate by bacteria and yeast isolates resulted in an increase in population density and subsequent decrease in pH value and residual aviation fuel concentration. Over 90% of the n-alkane fraction of the aviation fuel supplied at 0.5% v v-1 concentration was degraded in 14 days by Pseudomonas aeruginosa,Micrococcus luteus and Corynebacterium sp. There were differential growth responses by the strains to dodecane, benzene, toluene and naphthalene, while growth was not supported by hexane and cyclohexane.Thus, enrichment with of soil contaminated with aviation fuel led to the isolation of competent hydrocarbon degraders