Pharmaceutical Microbiology
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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 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 Suboptimal bacteriological quality of household water in municipal Ibadan, Nigeria(2024) Alabi, O. S.; Akintayo, I.; Odeyemi, J. S.; Oloche, J. J.; Babalola, C. M.; Nwimo, C.; Popoola, O.; Mogeni, O. D.; Marks, F.; Okeke, I. N.Access to potable water is difficult for many African residents. This study evaluated the bacteriological quality of household water collected in the dry and wet seasons across five municipal local government areas (LGAs) in Ibadan, a large city in southwest Nigeria. A total of 447 water samples (dry season, n 5 250; wet season, n 5 197) were aseptically collected from a random sample of mapped households within Ibadan’s five municipal LGAs. The pH values and total aerobic and coliform bacterial counts were measured, and samples were screened for Escherichia coli, Salmonella, Shigella, and Yersinia by standard phenotypic techniques and multiplex polymerase chain reaction. The most common source of water was well (53.2%), followed by borehole (34%). None of the households used municipal tap water. Cumulatively, aerobic (P 5 0.0002) and coliform (P 5 0.0001) counts as well as pH values (P 5 0.0002) changed significantly between seasons, with increasing and decreasing counts depending on the LGA. Nonpotable water samples were found to be very common during the dry (86.8%) and wet (74.1%) seasons. Escherichia coli spp., as indicators of recent fecal contamination, were isolated from 115 (25.7%) of the household water sources. Thirty three Salmonella, four enteroaggregative E. coli, and four enterotoxigenic E. coli isolates but no Shigella or Yersinia isolates were identified. This study revealed the absence of treated tap water and the poor quality of alternative sources with detectable pathogens in municipal Ibadan. Addressing the city-wide lack of access to potable water is an essential priority for preventing a high prevalence of feco-orally transmitted infections.Item Isolation of pathogenic strains of methicillin-resistant Staphylococcus aureus from mobile phones in a tertiary institution in Ibadan, Nigeria(2022) Alabi, O. S.; Ayoola, O. O.; Odeyemi, J. S.; Oaikhena, A. O.The health implications of mobile phones emission have been a matter of concern to health practitioners for decades but little or no attention has been given to the mobile phones as potential fomites for pathogens. This study isolated and characterised methicillin-resistant Staphylococcus aureus (MRSA) on mobile phones of students in a tertiary institution in Ibadan, Nigeria. One hundred swab samples were obtained from the surfaces of mobile phones of students in a cross-sectional study conducted between July and August, 2019. Presumptive staphylococci were isolated on mannitol salt agar and identities were confirmed by standard biochemical test and Gram-staining. Antimicrobial susceptibility test was done by disc-diffusion method and mecA or mecALGA251, tsst-1, eta and etb genes screened by PCR technique. Among the 200 presumptive S. aureus isolated, 163 (81.5%) were confirmed as S. aureus exhibiting resistance to ofloxacin (1.8%), gentamicin (3.7%), ceftriaxone (29.4%), ceftazidime (57.7%), cefoxitin (61.3%), cefuroxime (64.4%), erythromycin (85.3%), amoxicillin-clavulanic acid (86.5%) and cloxacillin (92%). Proportion of MRSA and methicillin-susceptible S. aureus (MSSA) were 61.3% and 38.7% respectively with significant difference in their level of antibiotic resistance to the cephalosporins (excluding ceftriaxone), penicillins, erythromycin and ofloxacin (p<0.05). All the MRSA strains were multidrug resistant (MDR) harbouring mecA or mecALGA251 (56.3%), tsst-1 (56.3%), etb (31.3%) and eta (12.5%) genes. This study detected a high proportion of methicillin-resistant, virulent S. aureus as fomites on surfaces of mobile phones among students of a tertiary institution. This is of public health concern and thus requires strong public education to avoid imminent spread and outbreaks.Item Detection of methicillin-resistant staphylococcus aureus and extended-spectrum beta-lactamase producers from ready-to-eat roasted beef in Ibadan north, Nigeria.(2021) Alabi, O. S.; Obisesan, A. O.; Odumosu, B. T.Ready-to-eat roasted beef popularly called `Suya' in Nigeria is a highly nutritive food and hence, prone to microbial contamination when handled in an unhygienic manner by the vendors. Extended-spectrum beta-lactamase (ESBL) producers and methicillin-resistant Staphylococcus aureus have been reported in both community and hospital settings in Nigeria. This study investigated their occurrence as microbial contaminants in ready-to eat roasted beef in Ibadan North local government area (LGA) of Oyo state, Nigeria. Fifty (50) samples were purposively collected randomly in four different locations in Ibadan North LGA from 1st to 31st of November, 2019. Aerobic and coliform bacterial counts, isolation, identification and antibiotic susceptibility testing were done using standard microbiological techniques. Phenotypically, methicillin resistant Staphylococcus aureus was detected by cefoxitin-disc-diffusion and ESBL-producers by double-disc synergy. MecA/C and selected ESBL (TEM, SHV and CTX-M) genes were detected by PCR technique. The mean total aerobic and coliform bacterial counts ranged from 1.5 × 106 to 7.8 × 106 cfu/g and 0.8 × 102 to 1.3 × 103 cfu/g respectively. Thirty-eight (38) bacteria were isolated: Staphylococcus aureus (15.8%), Pseudomonas spp. (42.1%), Klebsiella spp. (36.8%) and Bacillus spp. (5.3%). Four (66.7%) of the Staphylococcus aureus were MecA mediated methicillin-resistant strains and 20 (66.7%) of the Gram-negatives were ESBL-producers with 9 (30%) harbouring TEM and SHV and 15 (50%) CTX-M genes. Occurrence of MRSA and ESBL-producers in ready-to-eat roasted beef in Ibadan north is of serious public health concern. Policy and Practice.Item Co-production of extended-spectrum beta-lactamases and metallo beta-lactamases among multi-drug resistant gram-negative bacteria isolates collected from tertiary hospitals in Oyo State, Nigeria(FUDMA, 2020-09) Alabi, O. S.; Obisesan, A. O.; Taiwo, M. K.; Adewuyi, O. R.Extended-spectrum beta-lactamases (ESBLs) and metallo beta-lactamases (MBLs) are compromising the chemotherapeutic use of cephalosporins and carbapenems respectively. This study investigated the burden of ESBLs and MBLs co-production among multi-drug resistant (MDR) Gram-negative bacteria collected from two tertiary hospitals in Oyo State. A total of 240 non-duplicated clinical isolates of Escherichia coli, Klebsiella spp. and Pseudomonas spp. were collected from the Microbiology units of two tertiary hospitals in Oyo State and their identities authenticated using standard identification techniques. Antimicrobial susceptibility testing was carried out by disc-diffusion method and isolates exhibiting resistance to 3 classes of antibiotics selected as MDR strains. ESBL and MBL production was detected by double-disc synergy test (DDST) and combined-disc-diffusion test (CDDT) respectively. Selected beta-lactamase genes were detected by PCR, amplicons sent out for sequencing and phylogenetic tree of the sequences constructed using Mega X software. MDR was exhibited by 43.8% of the isolates. ESBLs and MBLs were produced by 32.4% and 7.6% of the MDR isolates respectively. Co-production of ESBL and MBL was observed in 6.7% of the MDR isolates. BlaCTX-M-15 (67.7%), blaTEM-1 (55.9%), blaSHV-1 (47.1%), co-existing blaTEM + blaSHV, blaTEM + blaCTXM, blaCTX-M + blaSHV (each in 5.9%) and blaCTX-M +blaTEM + blaSHV (26.5%) were detected among the ESBLproducers. MBL genes were not detected among the MBL-producers. Only blaTEM-1 sequences showed two different claudes on the phylogenetic tree. The occurrence of MDR isolates co-harbouring different classes of beta-lactamse genes observed in this study is of public health concern and hence, requires stricter control of antibiotic use.Item Evaluation of the antibacterial and antifungal potentials of peptide-rich extracts from selected Nigerian plants(Elsevier, 2022) Agbebi, E. A.; Alabi, O. S.; Nkrumah, A. O.; Ogbole, O. O.Introduction: Host defence peptides (HDPs) has gained wide recognition as a potential source of antimicrobial agents because of their abundance in nature, low incidence of reported resistance, and their immunomodulatory properties. This study investigated the presence and antimicrobial activities of bioactive peptides in seven selected plants from the Rubiaceae, Apocynaceae, and Euphorbiaceae families. Methods: The reversed-phase solid-phase extraction was used to obtain the peptide-rich fractions from the crude extracts of the plants, and the circular peptides were chemically detected by a modified G-250 spray on a developed TLC plate. The peptide fraction and crude extracts were screened for their antimicrobial activities using the broth microdilution method. The rate of kill study was conducted for the peptide fractions Euphorbia hirta and Nauclea diderichii Results: The study revealed Nauclea diderichii peptide-rich fraction as the most potent on the tested strains of gram-positive and gram-negative bacteria and fungi (MIC =7.8, 15.63-62.5, and 7.8 μg/mL respectively). Euphorbia hirta and Nauclea diderichii peptide fractions exhibited bactericidal activity (MIC index ≤4, and >3Log10 reduction of initial inoculum) and have a broad spectrum of activity, which further validates their ethnomedicinal use in the management of diverse infectious diseases, including enteric and respiratory tract infections. The peptide fractions of all the plants are more potent than the crude extracts. Conclusion: This study established the antimicrobial potentials of the peptide-rich fractions from these plant species, and the basis for further investigation to isolate and characterize the bioactive peptides responsible for their antimicrobial activities.