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Papers by Ezeamagu Cajethan

Journal of Microbiology and Antimicrobials

Multi-drug resistant bacteria are a public health problem associated with high morbidity and mort... more Multi-drug resistant bacteria are a public health problem associated with high morbidity and mortality globally. This increasing drug resistance has been linked to gene exchange between bacteria. Integrons are gene exchange systems and are known to play a significant role in the acquisition and dissemination of antimicrobial resistance genes especially in Gram negative bacteria. Hence, this study aims to evaluate integrons in members of Enterobacteriaceae obtained from clinical samples. Fortynine (49) isolates identified as Escherichia coli (45), Proteus mirabilis (2), Shimwellia blattae (1), and Klebsiella pneumoniae (1) were resistant to amoxicillin/clavulanate, cefuroxime, cefixime and ceftazidime while 43(87.76%), 45(91.84%), 46(93.88%) and 29(59.18%) of these strains were resistant to gentamicin, ofloxacin, ciprofloxacin and nitrofurantoin, respectively. Class 1 integrons were found in E. coli (18), Klebsiella pneumoniae (1) and Proteus mirabilis (1). This study revealed that large proportion of the strains studied were multi-drug resistant, and possessed integrons. Consequently, there is a need for proactive antibiotic surveillance system in both healthcare and community settings with a view to reducing the incidence and spread of antibiotic resistance genes between different species of bacteria.

Bacterial diversity and community structure of two maize varieties (white and yellow) during ferm... more Bacterial diversity and community structure of two maize varieties (white and yellow) during fermentation/steeping for ogi production, and the influence of spontaneous fermentation on mycotoxin reduction in the gruel were studied. A total of 142 bacterial isolates obtained at 24–96 h intervals were preliminarily identified by conventional microbiological methods while 60 selected isolates were clustered into 39 OTUs consisting of 15 species, 10 genera, and 3 phyla by 16S rRNA sequence analysis. Lactic acid bacteria constituted about 63% of all isolated bacteria and the genus Pediococcus dominated (white maize = 84.8%; yellow maize = 74.4%). Pediococcus acidilactici and Lactobacillus paraplantarum were found at all steeping intervals of white and yellow maize, respectively, while P. claussenii was present only at the climax stage of steeping white maize. In both maize varieties, P. pentosaceus was found at 24–72 h. Mycotoxin concentrations (μg/kg) in the unsteeped grains were: white maize (aflatoxin B 1 = 0.60; citrinin = 85.8; cyclopiazonic acid = 23.5; fumonisins (B 1 /B 2 /B 3) = 68.4– 483; zearalenone = 3.3) and yellow maize (aflatoxins (B 1 /B 2 /M 1) = 22.7–513; citrinin = 16,800; cyclopiazonic acid = 247; fumonisins (B 1 /B 2 /B 3) = 252–1,586; zearalenone = 205). Mycotoxins in both maize varieties were significantly (p < 0.05) reduced across steeping periods. This study reports for the first time: (a) the association of L. paraplantarum, P. acidilactici, and P. claussenii with ogi production from maize, (b) citrinin occurrence in Nigerian maize and ogi, and (c) aflatoxin M 1 , citrinin and cyclopiazonic acid degradation/loss due to fermentation in traditional cereal-based fermented food.

Aims: The increasing microbial drug resistance in recent times has necessitated the search for an... more Aims: The increasing microbial drug resistance in recent times has necessitated the search for an alternative antimicrobial agents derived from natural sources. Chromolaena odorata L. (Asteraceae) is one of such natural sources that has been reported to possess healing properties. In this study, the phytochemical constituents and antimicrobial properties of C. odorata leaf extract were investigated. Methodology: The leaves of C. odorata were collected from Babcock University garden, authenticated, prepared and extracted following standard procedures with methanol and ethyl-ether as extraction solvents. Phytochemical screening was carried out according standard protocol while antimicrobial screening was performed according to agar well diffusion method on the following organisms: Pseudomonas aeruginosa (ATCC19582), Shigella flexneri (KZN), Klebsiella pneumoniae (ATCC 10031), Enterococcus faecalis (ATCC 29212), Enterococcus cloacae (ATCC Original Research Article Odutayo et al.; JAMPS, 13(4): 1-9, 2017; Article no.JAMPS.33523 2 13047), Proteus vulgaris ATCC 6830, Escherichia coli (ATCC 25922) Enterococcus faecalis (KZN) and Neurospora crassa. Results: Of the nine phytochemicals screened (terpenoids, steroids, flavonoids, alkaloids, saponins, tannins, phlobatannin, phenols and anthraquinones), only one (phlobatannin) was absent in both solvent extracts. The antimicrobial activity of the extracts indicated least and highest zones of inhibition of 9 and 23 mm against Shigella flexneri (KZN) and Shigella sonnei (ATCC19930) respectively and fungicidal potency of 100% within 24 h on Neurospora crassa. Conclusion: Chromolaena odorata extract possesses antimicrobial activity and thus, represents a promising source for medicines of which when carefully tapped and explored has enormous therapeutic potentials.

Staphylococcus aureus is the most important cause of nosocomial and community associated infectio... more Staphylococcus aureus is the most important cause of nosocomial and community associated infections as well as the most pronounced species in drug resistance amongst Staphylococcus species. There have been reported cases of inconsistency in presumptive coagulase tests using commercial kits and conventional methods. This study therefore reports a simple, rapid, accurate and cost-effective PCR-RFLP-based molecular technique that separates and identifies to species level S. aureus from other coagulase negative staphylococci. Fifty clinical isolates of staphylococci previously isolated from various specimens were investigated for their ability to clot blood plasma. Of the 50 clinical isolates, 6 (12%) and 44 (88%) isolates yielded positive and negative results, respectively, for conventional tube coagulase test. The PCR-RFLP supplemented with species-specific primers classified these isolates into three distinct species: S. epidermidis (86%), S. aureus (12%) and S. xylosus (2%). Furthermore, the technique applied in this study classified the isolates into two RFLP patterns representing S. aureus and other coagulase negative staphylococci which correlated with coagulase test results. Since coagulase test could be sometimes misleading and inconclusive, this method could be substituted in routine laboratory program.

Aims: Staphylococcus species have been a major human pathogen of public health importance globall... more Aims: Staphylococcus species have been a major human pathogen of public health importance globally. This study was designed to evaluate the resistance pattern and plasmid profile of Staphylococcus species isolated from clinical and community settings. Methodology: Staphylococcus species from clinical (55) and community (53) which were previously isolated in University of Ibadan and her teaching hospital and identified as S. epidermidis (92.6%), S. aureus (6.5%) and S. xylosus (0.9%) were used. The antibiogram and plasmid profiles were determined by standard procedures.

Journal of Microbiology and Antimicrobials

Multi-drug resistant bacteria are a public health problem associated with high morbidity and mort... more Multi-drug resistant bacteria are a public health problem associated with high morbidity and mortality globally. This increasing drug resistance has been linked to gene exchange between bacteria. Integrons are gene exchange systems and are known to play a significant role in the acquisition and dissemination of antimicrobial resistance genes especially in Gram negative bacteria. Hence, this study aims to evaluate integrons in members of Enterobacteriaceae obtained from clinical samples. Fortynine (49) isolates identified as Escherichia coli (45), Proteus mirabilis (2), Shimwellia blattae (1), and Klebsiella pneumoniae (1) were resistant to amoxicillin/clavulanate, cefuroxime, cefixime and ceftazidime while 43(87.76%), 45(91.84%), 46(93.88%) and 29(59.18%) of these strains were resistant to gentamicin, ofloxacin, ciprofloxacin and nitrofurantoin, respectively. Class 1 integrons were found in E. coli (18), Klebsiella pneumoniae (1) and Proteus mirabilis (1). This study revealed that large proportion of the strains studied were multi-drug resistant, and possessed integrons. Consequently, there is a need for proactive antibiotic surveillance system in both healthcare and community settings with a view to reducing the incidence and spread of antibiotic resistance genes between different species of bacteria.

Bacterial diversity and community structure of two maize varieties (white and yellow) during ferm... more Bacterial diversity and community structure of two maize varieties (white and yellow) during fermentation/steeping for ogi production, and the influence of spontaneous fermentation on mycotoxin reduction in the gruel were studied. A total of 142 bacterial isolates obtained at 24–96 h intervals were preliminarily identified by conventional microbiological methods while 60 selected isolates were clustered into 39 OTUs consisting of 15 species, 10 genera, and 3 phyla by 16S rRNA sequence analysis. Lactic acid bacteria constituted about 63% of all isolated bacteria and the genus Pediococcus dominated (white maize = 84.8%; yellow maize = 74.4%). Pediococcus acidilactici and Lactobacillus paraplantarum were found at all steeping intervals of white and yellow maize, respectively, while P. claussenii was present only at the climax stage of steeping white maize. In both maize varieties, P. pentosaceus was found at 24–72 h. Mycotoxin concentrations (μg/kg) in the unsteeped grains were: white maize (aflatoxin B 1 = 0.60; citrinin = 85.8; cyclopiazonic acid = 23.5; fumonisins (B 1 /B 2 /B 3) = 68.4– 483; zearalenone = 3.3) and yellow maize (aflatoxins (B 1 /B 2 /M 1) = 22.7–513; citrinin = 16,800; cyclopiazonic acid = 247; fumonisins (B 1 /B 2 /B 3) = 252–1,586; zearalenone = 205). Mycotoxins in both maize varieties were significantly (p < 0.05) reduced across steeping periods. This study reports for the first time: (a) the association of L. paraplantarum, P. acidilactici, and P. claussenii with ogi production from maize, (b) citrinin occurrence in Nigerian maize and ogi, and (c) aflatoxin M 1 , citrinin and cyclopiazonic acid degradation/loss due to fermentation in traditional cereal-based fermented food.

Aims: The increasing microbial drug resistance in recent times has necessitated the search for an... more Aims: The increasing microbial drug resistance in recent times has necessitated the search for an alternative antimicrobial agents derived from natural sources. Chromolaena odorata L. (Asteraceae) is one of such natural sources that has been reported to possess healing properties. In this study, the phytochemical constituents and antimicrobial properties of C. odorata leaf extract were investigated. Methodology: The leaves of C. odorata were collected from Babcock University garden, authenticated, prepared and extracted following standard procedures with methanol and ethyl-ether as extraction solvents. Phytochemical screening was carried out according standard protocol while antimicrobial screening was performed according to agar well diffusion method on the following organisms: Pseudomonas aeruginosa (ATCC19582), Shigella flexneri (KZN), Klebsiella pneumoniae (ATCC 10031), Enterococcus faecalis (ATCC 29212), Enterococcus cloacae (ATCC Original Research Article Odutayo et al.; JAMPS, 13(4): 1-9, 2017; Article no.JAMPS.33523 2 13047), Proteus vulgaris ATCC 6830, Escherichia coli (ATCC 25922) Enterococcus faecalis (KZN) and Neurospora crassa. Results: Of the nine phytochemicals screened (terpenoids, steroids, flavonoids, alkaloids, saponins, tannins, phlobatannin, phenols and anthraquinones), only one (phlobatannin) was absent in both solvent extracts. The antimicrobial activity of the extracts indicated least and highest zones of inhibition of 9 and 23 mm against Shigella flexneri (KZN) and Shigella sonnei (ATCC19930) respectively and fungicidal potency of 100% within 24 h on Neurospora crassa. Conclusion: Chromolaena odorata extract possesses antimicrobial activity and thus, represents a promising source for medicines of which when carefully tapped and explored has enormous therapeutic potentials.

Staphylococcus aureus is the most important cause of nosocomial and community associated infectio... more Staphylococcus aureus is the most important cause of nosocomial and community associated infections as well as the most pronounced species in drug resistance amongst Staphylococcus species. There have been reported cases of inconsistency in presumptive coagulase tests using commercial kits and conventional methods. This study therefore reports a simple, rapid, accurate and cost-effective PCR-RFLP-based molecular technique that separates and identifies to species level S. aureus from other coagulase negative staphylococci. Fifty clinical isolates of staphylococci previously isolated from various specimens were investigated for their ability to clot blood plasma. Of the 50 clinical isolates, 6 (12%) and 44 (88%) isolates yielded positive and negative results, respectively, for conventional tube coagulase test. The PCR-RFLP supplemented with species-specific primers classified these isolates into three distinct species: S. epidermidis (86%), S. aureus (12%) and S. xylosus (2%). Furthermore, the technique applied in this study classified the isolates into two RFLP patterns representing S. aureus and other coagulase negative staphylococci which correlated with coagulase test results. Since coagulase test could be sometimes misleading and inconclusive, this method could be substituted in routine laboratory program.

Aims: Staphylococcus species have been a major human pathogen of public health importance globall... more Aims: Staphylococcus species have been a major human pathogen of public health importance globally. This study was designed to evaluate the resistance pattern and plasmid profile of Staphylococcus species isolated from clinical and community settings. Methodology: Staphylococcus species from clinical (55) and community (53) which were previously isolated in University of Ibadan and her teaching hospital and identified as S. epidermidis (92.6%), S. aureus (6.5%) and S. xylosus (0.9%) were used. The antibiogram and plasmid profiles were determined by standard procedures.