Pharmaceutical Microbiology
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Item Molecular screening of antibiotic-resistant determinants among multidrug-resistant clinical isolates of proteus mirabilis from SouthWest Nigeria(Makerere University Medical School (Uganda), 2017) Alabi, O. S.; Mendonça, N.; Adeleke, O. E.; Da Silva, G. J.Background: Globally, and particularly in developing countries, the menace of anti-microbial resistance is an accelerating problem. In Nigeria, increase in bacterial resistance has been phenotypically established but due to high cost, few molecular studies have been reported. Objectives: This study screened for presence of transferable resistance genes and mobile genetic elements (MGEs) such as integron among multi-drug resistant (MDR) P. mirabilis. Methods: A total of 108 P. mirabilis strains collected from five tertiary hospitals in SouthWest Nigeria were subjected to antibiotic susceptibility study using disc-diffusion method. Transferable resistance genes and MGEs were amplified using Polymerase chain reaction (PCR) analysis and amplicons sequenced. Results: Varied resistance was observed against all the antibiotics tested. About 56% of the isolates were MDR including those from 0-12 years old children. PCR analysis revealed the presence of aac(6’)-Ib (33.3%), plasmid mediated quinolone resistance (PMQR) genes [qnrA (36.7%), acc(6’)-Ib-cr (5%)], TEM (48.3%), CTX-M (6.7%) and integrons class 1 (58.3%) and class 2 (26.7%). Sequencing analysis revealed blaTEM-1, blaCTX-M-15 associated with ISEcp1 and eight different arrays of gene cassettes: aadA1, aadA1-qacH, aadB-aadA2, aadA5, dfrA7, dfrA15, dfrA17, dfrA17-aadA5. Conclusion: Transferable resistance genes in association with MGEs are present in Nigerian P. mirabilis thus their potential in disseminating resistance.Item Characterization, antimicrobial and catalytic activities of silver nanoparticles biosynthesized using aqueous extract of Euphorbia graminea(Istanbul Medipol University, Turkey, 2023) Thomas, O. E.; Alabi, O. S.; Osharode, P. E.Phytosynthesis of silver nanoparticles (AgNPs) is not only affordable and ecofriendly but provides a means of synthesizing phytochemical capped AgNPs with predefined characteristics. The objective of this study was the green synthesis of AgNPs that possess antimicrobial and catalytic activities using aqueous extract of Euphorbia graminea. Reactions parameters critical to the yield, size and morphology of the biosynthesized AgNPs were optimized using UV spectroscopy. The UV-visible spectra analysis of the biosynthesized AgNPs showed surface plasmon resonance occurred at 462 nm. Scanning Electron Microscopy with Energy dispersive X-ray analysis revealed the characteristic absorption band of AgNPs at 3 KeV and confirmed 73.66% composition of particles as metallic silver. The AgNPs appeared as well-separated, quasi-spherical particles with narrow size distribution of 6.77±0.89 nm when examined with Transmission electron microscopy. X-ray diffraction confirmed the crystallinity of the AgNPs with mean crystallite size of 7.65 nm. The biosynthesized AgNPs showed broad-spectrum antimicrobial activity against bacteria and fungi. The rate constant of the degradation of methylene blue in the presence of as-synthesized AgNPs was increased several folds to sec-1 from sec-1 in its absence. The prepared AgNPs could find applications as therapeutic coats in medical devices and in effluent treatment of chemical industries.Item Preliminary phytochemical screening, antimicrobial potentials and GC-MS analysis of Secamone afzelli Rhoem (asclepiadaceae) leaves extracts(Faculty of Physical Sciences and Faculty of Life Sciences, Univ. of Ilorin, Nigeria, 2020) Oyinloye, O. E.; Alabi, O. S.Secamone afzelli is used ethno-medicinally as remedies for stomach, colic and gastro-intestinal tract infections. This study screened the hexane, ethyl acetate and ethanol extracts of S. afzelli leaves for phytocompounds, antimicrobial activity and identified bioactive compounds in the most active extract using Gas Chromatography Mass Spectrometry (GC-MS) analysis. S. afzelli (200mg) leave was extracted by soxhlet apparatus using three solvents (hexane, ethyl acetate and ethanol) and the phytochemicals determined. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) was determined by agar-diffusion and agar-dilution methods respectively against selected resistant bacterial and fungal clinical isolates. The most active of the three crude extracts was analysed by GC-MS for bioactive compounds identification. Presence of carbohydrates, anthraquinone, glycosides, proteins, tannin, phenolic compounds and steroids were determined. The three extracts (hexane, ethyl acetate, and ethanol extracts) had antibacterial (Range of inhibition zone = 10 to 18 mm and MICs 12.5 to 200 mg/mL) but no antifungal activity. The ethanol extract was the most active with 29 bioactive compounds including piperazine, phytol, leucine methyl ester, N-methyl-N-(1-methylethyl)- 1Pentanamine, 7-propyl-pyrrolizin-1-thione and 4,5-dimethylnonane. The antibacterial activity and arrays of bioactive compounds detected in S. afzelli leaves suggest that the plant may be a good source of novel antimicrobial compounds.Item Antimicrobial evaluation of microencapsulated ciprofloxacin+Irvinga gabonensis gum against klebsiella SPECIES FROM PATients in a teaching hospital in Benin(African Scientific Research and Innovation Council (AU-ASRIC), 2023) Onyenwel, N. E.; Nnamani, N. D.; Nwafor, C. N.; Onojob, V. O .; Alabi, S. O .; Obun-Nnadi, C.; Adeboye, O. O.Klebsiella species causes nosocomial infections and other diseases. The use of Ciprofloxacin formulations has been adopted for skin and systemic infections, hence Irvingia gabonensis a specie of African trees in the genus Irvingia, was used for the microencapsulation of ciprofloxacin and used against sequenced disease causing Klebsiella species. Adopting the non-solvent addition of microencapsulation, drug-excipient compatibility test, batches of encapsulated ciprofloxacin + Irvinga gabonenesis, gelatin gum with the pure active ciprofloxacin were prepared from formula X. The FT-IR absorbance at different wavelength was recorded. The resultant microncapsulated drugs were screened for antimicrobial activity using the single disc agar diffusion against K. quasipneumoniae, K. aerogenes, and K. pneumoniae isolates. There were no difference in wavelength of FT-IR spectra of Irvinga gabonensis, pure active ciprofloxacin, and ciprofloxacin blend+Irvinga gabonensis gum. The pure active ciprofloxacin was very effective at the concentration of 8.3µg/mL(IC5o:1.02µg/ml) and 4.15(IC5o:0.08µg/ml) against all the Klebsiella species. The ciprofloxacin + Irvinga gabonenesis at 7.12 µg/mL (IC5o:0.90µg/mL) had significant zone of inhibition when compared to the pure active ciprofloxacin drug alone (IC5o:0.80µg/mL) at a concentration of 4.12µg/ml active ciprofloxacin. Based on the 95% mean inhibition concentration, ciprofloxacin + Irvinga gabonenesis gum (IC5o:0.90µg/mL) is a better excipient than ciprofloxacin + Gelatin gum (IC5o:1.38µg/mL). Ciprofloxacin + Irvinga gabonensis gum exerts effective antimicrobial activities and compatibility in terms of effective drug release.Item Effect of kunnu-zaki on clinical bacteria isolates(Academicjournals, 2012-03) Olaitan, J. O.; Adeleke, O. E.; Alabi, O. S.Ten clinical isolates of Gram-negative bacteria were exposed in agar-cup diffusion sensitivity test to Kunun-zaki, a non-alcoholic fermented beverage, taken from eighteen samples. The undiluted samples of the beverage appreciably inhibited the growth of all the bacteria tested including, remarkably, Pseudomonas aeruginosa, Vibro cholerae, Salmonella enterica and Staphylococcus aureus. The bacteria however varied in their sensitivities to the fractional dilutions of the samples. This antimicrobial effect represents another property for Kunun-zaki and obviates the possibility of public health risk in its consumption.Item GC-MS profiling and evaluation of antioxidant and antimicrobial properties of methanolic extract and fractions of the leaves of solanum dasyphyllum schumach and thonn(West African Postgraduate College of Pharmacists, 2023) Oyinloye, O. E.; Alabi, O. S.; Ademowo, O. G.Background: Solanum dasyphyllum is a plant with several ethno-medicinal uses and to date, there is little scientific validation of its folkloric claims compared to other species of the Solanaceae family. Objective: This study determined the antimicrobial and antioxidant potential of methanol extract and fractions of the leaves of S. dasyphyllum and identified the phyto-constituents using GC-MS technique. Methods: Crude methanolic extract of S. dasyphyllum leaves were subjected to Phytochemical screening and liquid-liquid fractionation. Crude extracts and fractions were subjected to antimicrobial screening, including minimum inhibitory concentrations (MICs) and minimum bactericidal/fungicidal concentrations (MBC/MFC) determination, time-kill kinetics study, antioxidant activity and Gas Chromatography-Mass Spectrometry (GCMS) analysis. Results: Phytochemicals present included flavonoids, alkaloids, saponins, cyanogenic glycosides, tannins and reducing sugars. Antimicrobial activities were recorded against all the isolates (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger, Rhizopus spp., Candida albicans and Penicillium spp.) with MIC between 0.25 and >4 mg/mL, MBC of 1 and >4 mg/mL and MFC of 0.5 and >4 mg/mL. Time-kill kinetics study showed dichloromethane and ethylacetate fractions to be bactericidal. Crude extract displayed moderate antioxidant (IC50 = 425.51μg/mL) and GC-MS analysis showed 29 metabolites, including phenols and polyphenols derivatives, benzofuranone derivative and esters of decanoic acid derivatives, all of which are known to have anti-infective and anti-oxidant properties. Conclusion: This study therefore elucidates the potentials of the Solanum dasyphyllum plant as a good source of bioactive compounds including those with anti-infective and antioxidant properties.Item Microbial and heavy metals contaminations among the commonly sold vegetables in Lagos State, Nigeria(Nigerian Society for Microbiology (NSM), 2021) Odumosu, B.T.; Njoku, E. J.; Fatunsin, O. T.; Adeogun, O. O.; Alabi, O. S.Assessments of heavy metals and microbial contaminations of vegetables cannot be overemphasized as vegetables are important components of human diet. Intake of heavy metalcontaminated vegetables poses high risk to human health. Heavy metal concentrations and microbial contamination in twelve (12) most consumed vegetables Talinum triangulare, Telfairia occidentalis, Vernomia amygdalina, Amaranthus hybridus, Ocimum gratissimum, Celosia argentea, Taraxacum officinale, Piper guineense, Lactuna sativa, Gnetum africanum, Gongronema latifolium, and Pterocarpus mildraedii was carried out using standard laboratory procedures. Antibiotic susceptibility testing against 6 structurally unrelated antibiotics (clindamycin, cefoxitin, cloxacillin, gentamycin, erythromycin and ciprofloxacin) were done on the isolates obtained using disk diffusion method. Total of 36 bacteria isolates were obtained comprising of Staphylococcus aureus (12, 33.3%), Bacillus spp. (23, 63.9%), Micrococcus spp. (1, 2.80%) which were identified based on cultural and biochemical identification. Twenty three Fungal isolates involving Aspergillus acelatus (7, 30.43%), A. fumigatus (7, 30.43%), A. niger (5, 21.74%) and Penicillium Spp (4, 17.40%) were identified based on cultural and fungal staining technique. The overall number of susceptibility for ciprofloxacin (72%), erythromycin (61%) and gentamicin (50%) were recorded. Antibiotic resistance were recorded for clindamycin (66%), cloxacillin (61%) and cefoxitin (45%). The heavy metals concentration on the examined vegetables were above WHO acceptable limit of 0.3mg/kg, 0.2mg/kg and 1.30mg/kg for Pb, Cd and Cr respectively. The bacteria isolated harbored antibiotic resistance mechanisms against antibiotics which calls for urgent measures to minimize all possible routes for contaminations.Item Bioactive constituents and antibacterial screening of two Nigerian plant extracts against selected clinical bacteria(Nigeria Association of Pharmacists in Academia (NAPA), 2016) Odumosu, B. T.; Salawu, O. T.; Oyeyemi, I.; Alabi, O. S.; Rufai, T. R.; Odunukan, O.Background: The growing desires to combat antibiotic resistance among pathogenic bacteria necessitate the need to search for new antimicrobials agents from other sources such as plants. Objectives: The present study investigated the antibacterial activities and bioactive components of Nymphaea lotus and Spondias mombin against selected clinical bacteria Material and Methods: Extracts of N. lotus and S. mombin were prepared by 72 hours maceration in 70% methanol. The antimicrobial susceptibility testing (AST) of Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Salmonella typhi, Staphylococcus aureus, Citrobacter freundi and, Klebsiella oxytoca against the two extracts was carried out by disk diffusion method while minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) was by agar-well dilution and broth dilution method, respectively. The bioactive compounds of the plants were identified by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Results: Extracts of N. lotus showed better antimicrobial activities than S. mombin against all the clinical bacterial isolates with an MIC range of 3.13 – >12.5mg/mL compared to S. mombin with MIC range of 6.25 – >12.5mg/mL. The GC-MS results revealed the presence of 21 and 25 compounds for N. lotus and S. mombin respectively. Benzoic acid derivatives were in abundance in both plants with approximately 71.5% and 82.1% in N. lotus and S. mombin respectively. Conclusions: The findings from this study provided further evidence on their ethno-botanical claims and additional information on the potentials of the studied plants as effective medicinal plants with antimicrobial activity against clinical bacteria. This highlights the need for continuous exploration of medicinal plants for novel compounds with better antimicrobial property as option for the treatment of resistant bacterial infectionItem Antibiotic susceptibility profiles of lactic and acetic acid bacteria isolated from ogi, yoghurt and human vagina in Nigeria(Faculty of Pharmaceutical Sciences, Ahmadu Bello University (ABU), Zaria, Nigeria, 2018-03) Murtala, M.; Alabi, O. S.; Ayeni, F. A .The beneficial effects of lactic and acetic acid bacteria in human foods are well documented, however, there are increasing safety concerns associated with the exposure of humans to live microbes including transferable antibiotic resistance determinant. Therefore this study determines the antibiotic susceptibility and resistance profiles of lactic and acetic acid bacteria previously isolated from fermented foods and human vagina and the presence of plasmids in the strains. The antibiotic susceptibility and resistance of the bacterial strains was determined by disc diffusion method and the MIC for resistant strains by VITEK 2 compact system. Plasmid extraction was evaluated by ZyppyTM Plasmid Miniprep Kit while the resistant strains were cured using ethidium bromide as mutagen. All the isolates showed varying levels of antibiotic susceptibility/resistance. All the isolates were susceptible to gentamicin and resistant to vancomycin followed by ciprofloxacin. In MIC determination, only the vagina isolates showed 25% resistance to gentamicin and 75% resistance to erythromycin. Overall, only one plasmid was detected from Acetobacter pasterianus which was isolated from yoghurt with size greater than 1kb. Microbial resistance to four antibiotics (Tetracycline, Ampicillin, Sulphamethoxazole/ Trimethoprim and Neomycin) in Lactobacillus plantarum and Acetobacter pasterianus were cured. The studied isolates exhibited high degree of susceptibility to the antibiotics and the curing of the four antibiotic resistant strains indicated that the resistance may be plasmid mediated which can be transferable. Therefore the bacteria strains with cured resistance are not safe for probiotic purpose.Item A preliminary investigation of prevalence of extended spectrum beta lactamases among enterobacteriaceae isolated from poultry farms in Ibadan, Nigeria(Nigeria Association of Pharmacists in Academia (NAPA), 2015) Ayeni, F. A.; Olujobi, O. F.; Alabi, O. S.Background: -Antibiotic resistance and extended spectrum beta–lactamase (ESBL) producing enterobacteriaceae are global health concerns and major problems for the treatment of different infections caused by enterobacteriaceae. Objective: -This study was carried out to determine the prevalence of phenotypically identified ESBL producers in enterobacteriaceae strains isolated from poultry farms in Ibadan. Material and Methods: Enterobacteriaceae were isolated from faecal samples of 45 chickens from 3 farms in Ibadan, Nigeria. The E. coli strains in the isolates were identified by biochemical methods. The susceptibility of all enterobacteriaceae strains to selected β lactam antibiotics were tested by disc diffusion method. ESBL production was tested by double disk synergy test and MIC determination (8–512 μg/ml) Results: - A total of 40 Enterobacteriaceae strains were isolated and 20 of the strains were identified as E. coli while 20 were tagged other Enterobacteriaceae strains. The E. coli strains were generally susceptible to tested antibiotics while other Enterobacteriaceae were relatively resistant. All the tested Enterobacteriacea were susceptible to cefepine. 15% of E.coli isolates were resistant to amoxicillin/clavulaniz and 38.9% of other Enterobacteriaceace isolates were resistant to cefoxitin. 5% of E. coli strains and 25% of other Enterobacteriaceae produced ESBL with concentration range of ˂8 μg/ml and >512μg/ml for antibiotics used singly and in combination with clavulanic acid respectively. Conclusions: - This study showed low occurrence of ESBL in E. coli strains but relatively high occurrence in other Enterobacteriaceae in poultries in Ibadan, Nigeria.. Therefore, there is need to control the use of antibiotics in poultry feeds and livestock production.