Open Access Original Research Article

Incidence of Methicillin Resistant Staphylococcus aureus Isolated from Nostrils of Mouau Students

Miracle I. Okoh, Philip C. Odoemena, Emmanuel K. Amanze, Jane K. Peter, Eberechukwu O. Azubuike, Chibuzo V. Nwokafor, Justina O. Omaba

South Asian Journal of Research in Microbiology, Page 1-8
DOI: 10.9734/sajrm/2021/v10i230223

Aim: This study is carried out to determine the prevalence of nasal carriage of staphylococcus aureus among Michael Okpara University of Agriculture Umudike (MOUAU) students and determine the antibiotics susceptibility pattern.

Methods: Nasal swab specimens collected from the anterior nares were cultured on mannitol salt agar. S.aureus isolates were identified by mannitol fermentation, coagulase positivity and catalase positivity. Antimicrobial susceptibility test was performed on Meuller-Hinton Agar (MHA) by modified Kirby-Bauer disc diffusion method.

Result: Out of the 100 swabs collected, S.aureus was isolated from 60% of the samples. Among colonized students, 63.3% (n=38) were from male students whereas 36.7% (n=22) were from female. The antibiotic susceptibility pattern of the Staphylococcus aureus isolates indicates that Staphylococcus aureus isolates showed high rate of sensitivity towards antibiotics as follows; Gentamycin (81.67%), followed by Ciprofloxacin  (80%), Levofloxacin (76.67%), Ceftriaxone (58.33%), and resistance towards antibiotics Imipenem (100%) followed by Cefotaxime (90%), Cefexime (83.33%), Cefoxitin (65%), azithromycin (55%) and cefuroxime (50%).

Conclusion: This study showed a high rate of nasal carriage of Staphylococcus aureus among MOUAU students and a high incidence of antibiotics resistant Staphylococcus aureus carriage.

Open Access Original Research Article

Comparative Study of Malaria Diagnosis: Rapid Diagnostic Test (RDTs) Against Microscopy among Pregnant Women Attending Antenatal Clinic in Specialist Hospital, Sokoto

K. Mohammed, M. U. Iduh, S. M. Saheed, O. F. Ashcroft, M. K. Garba, S. U. Nataala

South Asian Journal of Research in Microbiology, Page 9-16
DOI: 10.9734/sajrm/2021/v10i230224

Background: Malaria is an infectious disease caused by a protozoan parasite of the genus Plasmodium. It was estimated that 219 million cases of malaria occur in 87 countries, with an estimated death of 435,000 in 2017 among pregnant women. Other species include P. ovale, P. vivax, and P. malariae is a blood parasite of human and is one of the major public health burdens in developing countries, particularly in Sub-Saharan Africa. It is estimated that about 3.5 billion people globally and 450 million people are thought to be ill as a result of such infections, the majority being children.

Aims: This study was aimed at comparing RDTs against microscopy in the detection of malaria parasite among pregnant women. Samples were collected and analyzed following cross-sectional comparative study design. It was conducted between Septembers to November 2019.

Study Design: This was a cross-sectional, comparative study

Place and Duration of Study: This study was conducted among patients attending Specialist Hospital Sokoto, Sokoto State, between March and November, 2019.

Methodology: A total of 106 participants were enrolled for the study. Standard parasitological examination was carried out on blood samples using microscopy followed by Rapid Diagnostic test (RDTs).

Results: Finding revealed, in this study, CareStart kit had sensitivity of 77.7%, specificity of 100s%. It is expected that any RDT used for malaria diagnosis should have a high sensitivity of 95% and specificity 97% (WHO, 2003); this is in contrast with the RDTs results in this study.

The false negative (FN) Carestart and SD-Bioline kits in this study were 10% and 21%, respectively using microscopy as the gold standard due to lack of sensitivity of RDTs at low parsitaemia compared to microscopy.

The false positive rate in this study for the Carestart and SD-Bioline kits are 0% and 0% respectively. Out of 106 patients screened, 35% and 24% tested positive for Plasmodiumfalciparum using Carestart and SD-Bioline RDTs respectively, while 45% were positive to malaria by microscopic examination. There was high prevalence of malaria parasite among age group 18-23 which is 42.2%.

Conclusion: It can be concluded that using microscopy is more time consuming compared to RDTs due to the fact that the time taken to read the results for RDTs is within five minutes and that of microscopy is higher compared to RDTs. Over all prevalence of malaria by microscopy was 42.5% while the prevalence of malaria by Carestart and SD-bioline was 33% and 22.6% respectively. Conventional microscopy remains the gold standard compared to RDTs according to this study with the level of its sensitivity and specificity which is higher than RDTs.

Open Access Original Research Article

Isolation and Use of Bacillus thuringiensis for the Production of Bio-Insecticide in Control of Mosquito Larvae

A. A. Ibiene, S. D. Lawson, S. O. Enyinnaya, F. E. Amos, L. Nnodim, G. A. Uzah

South Asian Journal of Research in Microbiology, Page 17-21
DOI: 10.9734/sajrm/2021/v10i230225

Bacillus thuringiensis is a widely studied bacterium and it is known for its use in pest management. It is selectively active on pests and less likely to cause resistance; hence it is considered a suitable replacement to chemical pesticides. The study assessed the potential of Bacillus thuringiensis in controlling mosquito larvae. Bacillus thuringiensis isolates selected were tested against secondary stage larvae of mosquito. Thirty-six larvae (6 each) were transferred into each test tubes (7 x 9) cm with 30ml sterile distilled water. The stock suspension of cultures of Bacillus thuringiensis in broth was diluted to 107, 106, 10 5, 104, 103 and 102 in sterile water, following the McFarland standard method for microbial load count. The test tubes were kept at room temperature, larval mortality was observed over time within 24hrs. The results showed that all mosquito larvae died at the 107 and 106 dilutions but at dilutions 105, 104 and 103 though affecting mosquito larvae, it was highly dependent on time because there was a decrease in concentration. The study showed that B. thuringiensis is safe for use in aquatic environments, including drinking-water reservoirs, for the control of mosquito, black fly and nuisance insect larvae. The products should contain the ICPs and be free from other microorganisms and biologically active metabolites.

Open Access Original Research Article

Synergistic Toxicity of Phenols and Cadmium Ion Binary Mixtures on Bacillus Sp and Pseudomonas Sp

C. A. M. Abba-Father, J. C. Orji, C. E. Nwanyanwu, R. C. Nwokorie, E. S. Asiwe

South Asian Journal of Research in Microbiology, Page 22-31
DOI: 10.9734/sajrm/2021/v10i230226

Toxicity of Cadmium (Cd), 4-chlorophenol (4-CP), and 2,4-dichlorophenol (2,4-DCP) as single compounds and binary mixtures on Bacillus sp and Pseudomonas sp isolated from garden soil was assessed using inhibition of total dehydrogenase as toxicity response. Binary mixtures of metal and chlorophenol were composed using arbitrary concentration ratios (%) corresponding to metal/phenol mixtures of 20/80; 40/60; 50/50 and 30/70; 45/55, 50/50 for the chemical pairs: Cd/4-CP and Cd/2,4-DCP respectively. Results obtained showed that the binary mixtures of Cd/4-CP and Cd/2,4-DCP all exhibited a dose-dependent inhibition of dehydrogenase activity in the test isolates. The binary mixture of CD/4-CP exhibited higher toxicity in ratio 40/60 and 20/80 for the isolates Bacillus sp and Pseudomonas sp with IC50 values of 0.212±0.002 and 0.158± 0.008mM respectively. While for the mixture of Cd/2,4-DCP, toxicity was highest at the 50/50 and 45/55 ratio for Bacillus sp and Pseudomonas sp with IC50 values of 0.069±0.001mM and 0.068±0.001mM respectively. The binary mixtures of the chemicals evaluated showed a progressive inhibition of dehydrogenase activity with Pseudomonas sp showing a higher susceptibility. Isobolographic analysis of binary mixture interaction against Bacillus sp and Pseudomonas sp showed largely synergistic interactions. The combination of Cd with the chlorophenols resulted in a synergistic increase in the toxicity of the compounds to the test isolates. The toxicity of Cd/4-CP binary mixture ratios to dehydrogenase activity of Bacillus sp and Pseudomonas sp was in the order 40:60>50:50>20:80 and 20:80>50:50>40:60 respectively; similarly that of Cd/2,4-DCP mixtures were 50:50>45:55>30:70 and 45:55>50:50>30:70 for Bacillus and Pseudomonas sp respectively. The trend and implications of the toxicity interactions are further discussed.

Open Access Original Research Article

In-vitro Antibacterial and Synergistic Activities of Extracts of Allium cepa and Allium sativum with Selected Antibiotics on Escherichia coli and Staphylococcus aureus

Nnamchi Chukwudi I., Igu Ebenezer K., Akpi Uchenna K., Amadi Onyetugo C., Ugwu Kenneth

South Asian Journal of Research in Microbiology, Page 32-44
DOI: 10.9734/sajrm/2021/v10i230227

Aim: This study was aimed at investigating the antibacterial activities of extracts of Allium cepa and Allium sativum, as well as their synergistic activities with some selected antibiotics against the bacterial pathogens Escherichia coli and Staphylococcus aureus

Study Design: Onions (Allium cepa), garlic (Allium sativum) were used in this study. The study assessed how extracts of the plants alone or in combination with some commonly used antibiotics inhibited the growth of some bacterial pathogens using agar well diffusion method. 

Place and Duration of Study: The research was carried out in the Department of Microbiology, University of Nigeria, Nsukka over a period of 6 months.

Methodology: Extracts of Allium cepa and Allium sativum were obtained using ethanol, methanol and water (aqueous). Antimicrobial susceptibility tests were carried out by agar well diffusion technique.

Results: All extracts obtained showed evidence of antimicrobial property measured as the Inhibition Zone Diameter (IZD) on the test microorganisms. Values of these IZDs showed remarkable increases when used synergistically with antibiotics. For instance, aqueous extract of Allium sativum increased from a mean value of 16.5mm at 1.0mg/ml to values of 30.0mm and 38.0mm when used with tetracycline and ampicloxacillin respectively against Escherichia coli. The MIC and MBC values also dropped progressively, indicating that fewer synergistic mixtures were required to exert the same effects on the tested organisms. The phytochemical analysis strongly indicated the presence of flavonoids, glycosides and alkaloids, among other plant metabolites.

Conclusion: This result indicates that Allium cepa and Allium sativum showed strong antibacterial activity against the bacterial pathogens E. coli and S. aureus; and that synergism of the extracts with some antibiotics improved those activities. The potential of developing antimicrobials from these plants appears promising.