Open Access Original Research Article

Influence of Some Antibiotics and Essential Oils Used Alone or in Combination on the Vitality of Presumptive Probiotic Lactic acid Bacteria

Gislaine Aurelie Kemegne, Aurore Vanessa Nana Ngahmi, Abraham Nkoue Tong, Sylvain Leroy Sado Kamdem, Jean Justin Essia Ngang

Microbiology Research Journal International, Page 1-14
DOI: 10.9734/mrji/2021/v31i930341

Aims: The aim of this study was to assess the in vitro antibacterial activity of selected antibiotics and essential oils alone or in combination, on selected presumptive probiotic lactic acid bacteria.

Study Design: Experimental studies.

Place and Duration of Study: Department of Microbiology of the University of Yaounde I between August 2017 and December 2017 (5 months).

Methodology: The chemical composition of five essential oils was determined by gas chromatography coupled with Solid-phase micro extraction. Then the sensitivity of four lactic acid bacteria to the essential oils and four antibiotics was assessed by the well diffusion and macrodilution method. Subsequently, two essential oils active on these bacteria and broad spectrum antibiotics were combined according to the central composite design plan.

Results: In general, the chemical composition of essential oils is very diverse, with the example of carvacrol found only in Origanum compactum at 53.24% and thymol in Thymus vulgaris at 56.19% and in Origanum compactum at 15.28%. The antibacterial activity shows that the majority of antibiotics used are active on the bacteria in the study compared to the essential oils where two were active (Origanum compactum and Cymbopogon winterianus). The evaluation of the combinations of essential oils and antibiotics in terms of kinetics has given us three cases: the first case is the one with no acidity or no growth at all; the second is the one where growth is normal; the third where growth is delayed with a more pronounced latency phase.

Conclusion: This study suggest that the effect of essential oils and medicinal plant used alone or in combination to antibiotics on the gut microbiota have to be evaluated for validation as well as their toxicity activities before using them for human therapy.

Open Access Original Research Article

Sustainable Production of Bioethanol by Zymomonas mobilis and Saccharomyces cerevisiae using Rice Husk and Groundnut Shell as Substrates

A. J. Na’Allah, M. Y. Iliyasu, U. S. Haruna, A. Ahmad, S. O. Oguche, K. I. Karamba, M. Abba, E. B. Agbo

Microbiology Research Journal International, Page 15-26
DOI: 10.9734/mrji/2021/v31i930342

Background of Study: Plant waste such as rice husk and groundnut shell are generated in large amounts, these waste presents a tremendous pollution to the environment. Worldwide, these wastes are often simply dumped into landfills and oceans or used as animal feeds. The recovery of food processing wastes as renewable energy sources represents a sustainable option for the substitution of fossil energy in order to minimize environmental damages and to meet energy demands of the growing population.

Aim: To produce bioethanol from rice husk and groundnut shell using local strains of Zymomonas mobilis and Saccharomyces cerevisiae.

Place and Duration of Study: Conducted at the Microbiology Laboratory of Abubakar Tafawa Balewa University Bauchi, Bauchi state, Nigeria, between April to June, 2021.

Methods: Groundnut shell and Rice husk were collected from local milling center. The wastes were powdered, sieved and used as carbon source. Proximate composition of the subsrate was done and the total carbohydrate was determined by difference. The sum of the percentage moisture, ash, crude lipid, crude protein and crude fibre was subtracted from 100. Zymomonas mobilis and Saccharomyces cerevisiae were isolated from rotten sweet oranges and locally fermented beverage (‘kunun-zaki’) respectively by growing them on Malt Yeast Peptone Glucose Agar (MYPGA) after which they were further screened for their ability to tolerate ethanol and they serve as organisms for fermentation. The enzyme α- amylase was used for hydrolysis. The fermented substrates were distilled at 78oC and the distillate was collected as bioethanol in a conical flask. UV-VIS spectrophotometer was used to determine the absorbance of each concentration (0, 0.2, 0.4, 0.6 and 0.8cm3) of reducing sugar content of the hydrolysates and the bioethanol produced by developing a standard curve at a wavelength of 491nm and 588nm respectively. The concentration of reducing sugar and bioethanol was determined using a reference line from the Standard curve.

Results: Proximate analysis done shows that rice husk have 70.09% carbohydrates while groundnut shell has 65.09% carbohydrates. Groundnut shell yielded the highest reducing sugar of 5.096%. Rice husk yielded the lowest quantity of reducing sugar with a total yield of 2.962%. Maximum concentration of bioethanol of 0.971% was produced from the combination of Saccharomyces cerevisiae and Zymomonas mobilis from groundnut shell. The lowest concentration of 0.121% of bioethanol was produced when Saccharomyces cerevisiae was used on rice husk hydrolysates. The synergistic relationship of Saccharomyces cerevisiae and Zymomonas mobilis yielded the maximum bioethanol when compared with the yield obtained when the organisms were used singly. Zymomonas mobilis produced highest bioethanol content when the organisms are used single.

Conclusion: This study demonstrates the potentiality of local strains of Saccharomyces cerevisiae and Zymomonas mobilis isolated from rotten sweet orange and locally fermented beverage (‘kunun-zaki’) to produce bioethanol by fermenting the rice husk and groundnut shell hydrolysates.

Open Access Original Research Article

Evaluation of the Bacteriological Quality of Milk Sold in Nnewi, Nigeria

V. Ezugwu Nnenna, R. Agbakoba Nneka

Microbiology Research Journal International, Page 27-34
DOI: 10.9734/mrji/2021/v31i930343

Introduction: Contamination of milk products can result to severe intestinal and extra-intestinal diseases in man. This study was aimed at evaluating the bacteriological quality of various milk products sold in Nnewi. 

Materials and Methods: Using the Cluster sampling technique, 30 milk samples (5 pasteurized skimmed milk, 5 powdered infant milk formulas, 5 powdered milk, 5 unsweetened evaporated milk, 5 branded soya milk and 5 unbranded soya milk) were purchased randomly from different shops and hawkers around Nnewi. Sample processing was done by serially diluting samples in sterile 1% peptone water before plating onto Mannitol Salt Agar, Violet Red Bile Glucose Agar, Blood Agar, MacConkey and Cysteine Lactose Electrolyte Deficient (CLED) agar using the Pour-plate technique. Bacterial count and identification were done using standard bacteriological as well as molecular techniques.  The molecular techniques used were Polymerase Chain Reaction, Sanger Sequencing and BLAST analysis on the NCBI BLAST online.

Results: This showed that 15 (50%) out of 30 milk samples were contaminated to varying degrees with bacteria. Nine (9) samples showed the presence of Escherichia coli with 32.14% of all the milk samples tested. E. coli was present in skimmed milk (20%), evaporated milk (20%), branded soyamilk (40%) and unbranded soyamilk (100%) but was not isolated from Infant formula and Powder milk. Klebsiella spp. showed the second highest prevalence (28.57%) and was present in evaporated milk (20%), branded soyamilk (40%), unbranded soyamilk (100%). Salmonella spp. (3.57%) was isolated from unbranded soyamilk,Enterobacter spp. (14.29%) was isolated from powder milk and in unbranded  soyamilk samples, Staphylococcus aureus(3.57%) and Staphylococcus epidermidis (3.57%) were isolated only in unbranded soyamilk, Macrococcus caseolyticus (3.57%) was isolated from unbranded soyamilk. Novel species such as Aquitalea magnusonii (3.57%), Alishewanella fetalis (3.57%) and Lysinibacillus macroides (3.57%) were identified by molecular analysis to be present in infant formula, evaporated milk and unbranded soyamilk respectively.

Conclusion: This research revealed that the bacteriological quality of some milk and milk products sold in Nnewi is not acceptable especially the unbranded soyamilk samples that showed gross contamination.

Open Access Original Research Article

Chromosome Mediated Fluoroquinolone and Extended Spectrum Beta-lactamase Resistant Genes in E. coli of Poultry Origin in Ekiti State

A. O. Oluyege, K. O. Ojo

Microbiology Research Journal International, Page 35-51
DOI: 10.9734/mrji/2021/v31i930344

Background: One health approach aimed at solving global health crisis links human, animal, and environmental health. This inclusive strategy has contributed to antibiotic classification in both human and animal medicine.

Aims: The aims of this research work are to determine the phylogenetic relationship of E. coli isolated from poultry and waste sources. The presence of chromosome mediated fluoroquinolone and extended spectrum beta-lactamase resistant genes will also be detected in the isolates.

Study Design: Experimental design.

Methodology: Data on farming attitudes of poultry farmers were collected using a questionnaire. E. coli was isolated from fresh poultry droppings and waste disposal sites using eosine methylene blue agar. The antibiotic sensitivity profile of the isolates was determined using the modified Kirby Bauer disc diffusion method. Phenotypic expression of fluoroquinolone (qnrS) and beta-lactamase (blaCMY) resistant traits were further detected using Polymerase Chain Reaction. The 16S rRNA gene sequencing was carried out followed by sequence alignment of E. coli genes with those from GenBank sources to determine the molecular identity of the isolates. Spearman’s correlation coefficient (rs) was run to determine the relationship between antibiotic treatment and resistant profile of the isolates. The phylogenetic relationship of the isolates was determined using Bio edit and Mega 6 software.

Results: Organic poultry farming was practiced by small-scaled, peasant farmers who raised free range birds while antibiotics were widely used on farms that adopted intensive mode of               farming. The percentage occurrence of E. coli from waste disposal sources was lesser than that from fresh poultry droppings. Highest percentage of antibiotic resistance to the fluoroquinolones was found while the carbapenemase recorded the lowest. Statistical analysis shows that antibiotic treatment in poultry and resistant profile of isolates to antibiotics are directly related. The percentage similarity of gene sequence with those from Gene Data Bank (≥99.29%) validates the identity of the isolates as E. coli. About, 60% of the sampled population had the qnrS gene with a band size of approximately 322 base pair. Besides, 40% of the sampled isolates possessed the blaCMY gene with a band size of approximately 460 base pair. Both genes co-existed in the chromosome of 15% of the sampled isolates sourced from poultry droppings and waste sources. Phylogenetic classification links the origin of isolates from waste disposal sources to poultry production sites. Besides, variant strains of multiple antibiotic resistant E. coli from poultry with antibiotic treatment were more diverse compared to those obtained from birds raised without antibiotics.

Conclusion: The qnrS and blaCMY genes found in multiple antibiotic resistant E. coli mediated resistance to critically important antibiotics. The co-existence of these genes in variants strains of E. coli occupying different phylogenetic clusters suggests that antibiotics were widely used on the   birds. Antibiotic treatment regimen in poultry may be responsible for the expression of antibiotic resistant genes found in the chromosome of the variant strains of E. coli.

Open Access Original Research Article

Assessment of Microbial Contaminations Associated with Steering Wheels and Palms of Commercial Drivers at the University of Cape Coast’s Taxi Rank

F. A. Osei, H. D. Nyarko, A. Atter

Microbiology Research Journal International, Page 52-57
DOI: 10.9734/mrji/2021/v31i930345

Aims: The study aimed at enumerating, identifying and showing similarities and variation of microbial species found on the palms of drivers and steering wheels.

 Methodology: Twenty-one (21) samples each from steering and palms were randomly collected into sterile bags and transported to the microbiology laboratory of the Department of Laboratory Technology for microbial analyses. Samples were cultured on Plate Count Agar (PCA), McConkey and Sabouraud Dextrose agar (SDA) for enumerations and identifications of total viable counts, bacteria and yeast and molds, respectively.

Results: Steering wheels had the highest microbial load (9.48 x105cfu/ml) whilst the palms of drivers had the lowest (8.88 x 105 cfu/ml) and that all 42 samples (100%) investigated were contaminated. A total of 163 bacteria of eight (8) different genera were obtained from both steering wheels and palms as well as sixty-two (62) fungi species made of five (5) different genera were also obtained. Bacterial isolates included Staphylococcus aureus, Escherichia coli, Proteus spp, Bacillus spp, Klebsiella pneumonia, Pseudomonas aeroginosa, Citrobacter spp and Enterococcus faecalis. For fungal genera, Altenaria alternata, Aspergillus fumigatus, Aspergillus niger, Penicillium spp, Candida spp were isolated. The steering wheels had higher bacterial and fungal contaminations than the palms of the drivers which showed no significant difference (P = 0.0832). This indicates that though there were numerical difference in contamination load, their effects were independent of each other.

Conclusion: This study confirms the contamination of fomites by microbes and the assertion that fomites are sources of transmission of many diseases.