P. O. Okerentugba

Petroleum degrading potentials of single and mixed microbial cultures isolated from rivers and refinery effluent in Nigeria

The ability of three bacterial isolates (Bacillus spp, Micrococcus spp and Proteus spp.) and some fungal species (Penicillin spp., Aspergillus spp. and Rhizopus spp.) isolated from two rivers and refinery effluent to degrade two Nigerian Crude oils was studied. The results showed changes in pH, optical density and total viable count for the bacterial isolates after a 17-day period. There was an increase in biomass for the fungal isolates after a 35-day period. It was observed that these organisms were able to utilize and degrade the crude oil constituents, with bacterial isolates showing increase in cell number and optical density as pH decreases. Single cultures were observed to be better crude oil degraders than the mixed cultures (bacteria or fungi). It was also observed that oil degraders could be isolated from a non-oil polluted environment, although those from oil-polluted environments have higher degradation potentials.

Performance and efficiency of a yeast biofilter for the treatment of a Nigerian fertilizer plant effluent

A biofilter composed of yeasts and cassava peel was used to detoxify fertilizer plant effluent. The biological oxygen demand was reduced on treatment from a range of 1200–1400 mg/l to a range 135–404 mg/l. The ammonia-nitrogen (NH3–N) and nitrate-nitrogen (NO3–N) were reduced after treatment from 1000 to 10 mg/l and from 100 to 17.6 mg/l, respectively. The biofilter is simple and easy to handle with high efficiency of 98%.

Molecular Assessment of Microbial Species Involved in the Biodegradation of Crude Oil in Saline Niger Delta Sediments Using Bioreactors

Purpose: At elevated salinities conventional microbiological processes are not very effective, therefore clean up of contaminants using bioremediation strategy will involve the use of halophilic and halo-tolerant bacterial species. This research therefore aimed at isolating and identifying potential halophilic and halo-tolerant bacterial species capable of hydrocarbon degradation during bioreactor based treatment with exogenous nutrients. Methods: The diversity of indigenous bacterial species with potential to degrade hydrocarbons was investigated using both culture-dependent and independent techniques. Bioremediation of hydrocarbon contaminated saline sediments was carried out using seven 2.5 liter bioslurry bioreactors operated over a 64-day period. Physicochemical parameters monitored were pH, nitrate, phosphate, total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbon (PAH), temperature, salinity, and total organic carbon (%TOC). Results: The baseline TPH, PAH and pH of the sediments were 19 ppm, 3.1 ppm and 7.0 respectively. The baseline salinity of the sediment was 10% thus the sediment was adjudged moderately saline. TPH ranged from 97 ppm-105 ppm on day zero and decreased to an average of 5.62 ppm on day 64, while PAH ranged from 56 ppm-61 ppm on day zero and decreased to an average of 4.02 ppm on day 64. The bacterial species identified as potential hydrocarbon degraders includes Halomonas lutea, Achromobacter spp, Aquitalea magnusonii, Bacillus sp, Sphingobacterium sp, Shewanella sp, Brevundimonas naejangsanensis, Pseudomonas pseudoalcaligenes, Pseudomonas aeruginosa, unidentified bacterium BH23 and Gordonia sp. The genus Pseudomonas formed majority of the isolates successfully sequenced and exhibited similarity values ranging from 91% to 100% with sequences deposited in GenBank. A combination of both molecular and culture based technique allowed the identification to species level of twelve isolates. One isolate could not be identified while the remaining isolates were identified to their generic level. Treatment BCD recorded highest total culturable heterotrophic bacteria (TCHB) count (7.1 × 108 cfu/g) and total culturable hydrocarbon utilizing bacteria (TCHUB) count (6.7 × 108 cfu/g). There was a significant difference at P<0.05 in TCHUB bacteria counts between the unamended bioreactor slurries and those amended with organic and inorganic nutrients. There were also significant differences in TCHUB counts when the bioaugumented slurry was compared with those amended with NPK, Urea and cow dung using one way ANOVA and Tukey’s multiple comparison tests. Conclusion: This study revealed potentially novel bacterial species and previously described hydrocarbon degrading bacterial species that can be characterized further to determine their role in hydrocarbon degradation as well as their salt tolerance level prior to application in bioremediation of saline environments.

Resistant plasmid profile analysis of multidrug resistant Escherichia coli isolated from urinary tract infections in Abeokuta, Nigeria.

BACKGROUND Multi-drug resistant Escherichia coli has become a major threat and cause of many urinary tract infections (UTIs) in Abeokuta, Nigeria. OBJECTIVES This study was carried out to determine the resistant plasmids of multidrug resistant Escherichia coli isolated from (Urinary tract infections)UTIs in Abeokuta. METHODS A total of 120 Escherichia coli isolates were obtained from urine samples collected from patients attending inpatient and outpatient clinics presenting UTI; with their biodata. Antibiotics susceptibility was performed and multi-drug resistant isolates were selected for plasmid profiling. Plasmids were extracted by the alkaline lysis method, electrophoresed on 0.8% agarose gel and profiled using a gel-photo documentation system gel. RESULTS Escherichia coli isolates obtained shows high resistance to cloxacillin (92.5%), amoxicillin (90.8%), ampicillin (90.8%), erythromycin (75.8%), cotrimoxazole (70.0%), streptomycin (70.0%) and tetracycline (68.3%) while 85.8% and 84.2% were susceptible to gentamycin and ceftazidime respectively. Sixteen Escherichia coli strains were observed to be resistant to more than two classes of antibiotics. The resistant plasmid DNA was detectable in 6(37.5%) of the 16 multidrug resistant Escherichia coli having single sized plasmids of the same weight 854bp and were all resistant to erythromycin, cefuroxime, cloxacillin, amoxicillin, ampicillin and cotrimoxazole. CONCLUSION This study has highlighted the emergence of multidrug resistant R-plasmids among Escherichia coli causing urinary tract infections in Abeokuta, Nigeria. There is a high level of resistance to many antimicrobials that are frequently used in Abeokuta, Nigeria.

Biodegradation of Total Petroleum Hydrocarbon by Aerobic Heterotrophic Bacteria Isolated from Crude Oil Contaminated Brackish Waters of Bodo Creek

Bodo creek is located in Gokana Local Government Area of Rivers state and is characterised by brackish water which is heavily contaminated with crude oil. Water samples collected from the creek were taken to Environmental Microbiology Laboratory of University of Portharcourt for isolation of aerobic heterotrophic bacteria using serial dilution spread plate technique. Isolation of morphologically distinct pure cultures was done and the isolates obtained were identified molecularly on the basis of 16S rRNA gene sequence analysis. 16S rRNA sequencing for identification of the isolates generated sequences ranging from 500 bp to 1700 bp and a 250 bp size PCR amplified fragment. The nucleotide sequence of the 16S rRNA gene was compared with published 16S rRNA sequences using BLAST search at the data base of National Centre for Biotechnology Information (NCBI). Biodegradation of petroleum hydrocarbon test on the isolates was conducted using Bony light crude oil obtained from Shell Petroleum Development Company and monitored using GC-FID (Agilent 6890 model) for 49 days. The initial quantity of TPH was 24091 and 6706 mg/l on day 0 for aerobic heterotrophic treatment and crude oil contaminated control and decreased progressively to 212.8 and 1174 mg/l respectively on day 49 indicating biodegradation in the treatment and control. Loss of TPH was statistically significant using one way analysis of variance (ANOVA) p<0.05 with time. Model for predicting TPH loss was developed and rate of biodegradation of the isolates determined using Trend line method of Microsoft Excel, 2010. The growth of bacteria cells increased progressively with decrease in TPH implying that the bacteria were responsible for biodegradation. Further application of bioremediation strategies in Bodo creek for biostimulation of the crude oil biodegrading bacteria for reclamation and restoration of an efficient ecosystem structure and function is suggested.

Antibiogram and plasmid profiling of carbapenemase and extended spectrum Beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae in Abeokuta, South western, Nigeria.

BACKGROUND The increased reports of ESBL dissemination from various centres in south western, Nigeria and the recent emergence of carbapenem resistant bacteria prompted the conception of this study. OBJECTIVES To demonstrate the relationship between high molecular weight plasmids and the expression of antibiotic multi-resistance including ESBL and carbapenemase. METHODS We investigated 97 isolates of selected organisms consisting of 67 E. coli and 30 Klebseilla spp for the presence of plasmids expressing ESBL including carbapenem-hydrolysing enzymes. Beta-lactamase was determined using acidometric method, while ESBL and carbapenemase activity was determined using the double-disk diffusion test as well as the Modified Hodge test (MHT). Plasmid profiles of ESBL and carbapenemase positive isolates were determined according to standard protocols. RESULTS An ESBL prevalence rate of 21.6% and carbapenem- resistance rate of 9.3% was recorded. Antibiotic susceptibility profile of ESBL isolates showed 100.0% resistance against Amoxicillin, Cotrimoxazole and Erythromycin. Moderate susceptibility was recorded against the Quinolone class of antibiotics; Meropenem remained the most active antibiotic against ESBL isolates with 62.5% against E. coli and 60% against K. pneumoniae. The plasmid profiles of our study isolates ranged from 11.8kbp to 35.5kbp. CONCLUSION Due to the relationship between high molecular weight plasmids and multi-drug resistance, we hereby recommend regular molecular surveillance of this form in our study setting.

Seroepidemiology and High Negativity of IgG Antibodies Against Human Papillomavirus (HPV) Type 6, 11, 16, and 18 Virus-like Particles in Women of Childbearing Age in Port Harcourt, Nigeria

This study reports the seroepidemiology and high negativity of IgG antibodies against the most common low- and high-risk HPVs among sexually active women of childbearing age in Port Harcourt, Nigeria. A total of 182 consented women (age range 19–45 years) were consecutively recruited to participate in the study. Using a Performa specifically designed for this study, pertinent socio-demographic/behavioral data were collected. Five 5 mL blood samples were also collected (aseptically) from each woman. Plasma of each sample was assayed for HPV-6/11/16/18 virus-like particles using a HPV IgG ELISA kit (Dia.Pro). The study showed a high overall anti-HPV seronegativity of 95.1% among these women. High group-specific seronegativity was also observed which ranged from 90.0 −100.0%. None of the variables evaluated showed statistical association with the HPV seronegativity. This study further confirmed the presence of HPV and susceptibility of a large population of women in their childbearing age to infections with these four HPV genotypes in Nigeria. Our findings therefore advocate for routine and early screening and clinical evaluation of all women of childbearing age for HPV- infection and -related manifestations.

CORRELATION OF HIV-1 P24 ASSAY WITH CD4 T-CELL COUNT, HIV, HBV AND HCV CO-INFECTIONS AND ITS IMPLICATION FOR ART MONITORING IN VASTLY HIV-INFECTED POPULATION OF NIGERIA

Background Reports indicate that extensive genetic diversity of HIV-1 impacts almost every aspect of HIV-1 epidemiology, including laboratory detection, ART/resistance, monitoring of ART and vaccine development. Therefore, in order to support the scale-up of access to HAART to mitigate the HIV-1 scourge, prompt, accurate and cost-effective diagnosis and monitoring of ART is crucial in Nigeria (a resource-limited country). Methods Plasma of 200 confirmed HIV-1 patients on a specified and uniform ART regimen was monitored with P24 antigen assay and CD4 T-cell count as virologic and immunologic assessments of response to ART. The results of the assays (P24 and CD4 count) were compared to assess sensitivity, turn-around time and financial advantages of P24 over the CD4 count. Serological analysis of HBV and HCV were performed according to the manufacturers instructions. Enumeration of CD4+ levels was done with a Partec flow cytometer. Results Of these patients, 77.5% had HIV only, 14.5% had HIV−HBV and 11.5% had HIV-HCV. Evaluation of levels of P24 antigen revealed that lower limits for P24 antigen 0.577–2.308 were detected in the subjects with CD4 cell count >500. However, higher limits for P24 antigen 2.308–2.885 were detected in subjects with CD4 cell count within the range of 200–499. Correlation analysis showed an inverse relationship between CD4 count and level of P24 antigen (CD4 count of 200–499 cells/µl versus 2.308–2.885 of P24, r=–0.319, CD4 count≥500 cells/µl versus 0.577–2.307 of P24, r=–0.088). Conclusions This study suggests that p24 could serve as one of such diagnostic and monitoring facilities that could be used in a resource-limited area like Nigeria. This will in turn lead to selection of more specific ARV options that best suppress viraemia during initiation of ART, as well as for monitoring HIV-1 patients in Nigeria, knowing that the virus subtype impacts effectiveness of ART.

HBV and HIV Coinfections among Intending Blood Donors in Port Harcourt, Nigeria

HBV is a major public health concern as it afflicts an estimated 350 million people worldwide. Studies are crucial and necessary to give us a better understanding of the epidemiology of the diseases in developing countries. A clearer picture of HBV/HIV prevalence in Africa is important in order to better educate the population and control these epidemics. This study estimated the seroprevalence of HBV/HIV coinfections among intending blood donors in Port Harcourt, Nigeria. In this cohort study, we collected blood samples from 178 intending blood donors who were confirmed to be HIV-seropositive at the University of Port Harcourt Teaching Hospital (UPTH) from September 2012 to June 2013. Commercial ELISA was used to assay for the presence of HBsAg among these subjects. The overall prevalence was found to be 6.7%. Sex and education (P < 0.05) were the main correlates in this study. Age was not statistically correlated (P > 0.05) in this study. We also observed a high overall HBV/HIV co-infection seronegativity of 93.3% among these blood donors. Group-specific seronegativity was also high ranging from 86.4–100.0%. Although the age groups (13–20, 21–35, and 36–66 years) insignificantly differed, none of their variables showed statistical association with the seronegativity. Our findings underscore the importance of screening for HBV/HIV among blood donors in developing countries, and particularly in sub-Saharan Africa, where the epidemics are still growing and a major public health concern.