DEPARTMENT OF PHARMACEUTICAL MICROBIOLOGY AND BIOTECHNOLOGY

This study examined the modulation of Escherichia coli growth by Lactobacillus rhamnosusinthe presence of polyethylene glycol (PEG), glycero-gelatin, and Theobroma. Growthkineticswere analysed using regression models of colony-forming unit counts over time. In monoculture, E. coli exhibited exponential growth (y = 6.6 + 0.21x, R² = 0.874). Co-culture with L. rhamnosussignificantly suppressed E. coli proliferation (y = 5.97 + 0.02x, R² = 0.324; p < 0.001). Theinclusion of glycero-gelatin moderately stabilized this inhibition (y = 5.93 + 0.03x, R² =0.462; p< 0.001), while PEG produced a synergistic effect, completely halting E. coli growth (y =4.46−0.003x, R² = 0.005; p < 0.001). In contrast, Theobroma reversed inhibition (y = 8.13 +0.17x, R² = 0.679; p = 0.436). These results indicate that physicochemical conditions strongly influenceprobiotic–pathogen interaction, with PEG amplifying inhibition, glycero-gelatin enhancingstability, and Theobroma antagonizing probiotic action against Escherichia coli.

Probiotic organisms coexist with a diverse range of pathogenic microbes within mucosal environments, where survival is influenced by ecological competition and surrounding physicochemical conditions. Lactobacillus reuteri is known to exert antagonistic effects against Escherichia coli, yet its viability can be altered by the medium in which it is delivered. This study evaluated the survival of L. reuteri in selected suppository bases in the presence of E. coli. L.
reuteri was incorporated into glycerogelatin, polyethylene glycol (PEG), and theobroma bases, and co-incubated with E. coli. Viable counts were monitored over time and survival was analysed using linear regression, while differences in survival relative to the control were evaluated using
paired t-test. Theobroma supported the highest survival of L. reuteri (slope = 0.26; R2 = 0.795), followed by
polyethylene glycol (slope = 0.25; R2 = 0.799), indicating that these environments better maintained microbial viability under competitive stress. In contrast, glycerogelatin significantly reduced L. reuteri survival (slope = 0.06; R2 = 0.229), with the reduction being highly significant
(P < 0.001), suggesting strong susceptibility to inhibitory effects. The result of the finding indicate that the survival of L. reuteri in the presence of E. coli is markedly influenced by the surrounding base, and theobroma base with a lipid and polymeric nature provide more favorable conditions for probiotic persistence than glycerogelatin which is a hydrophilic gelatinous systems.

Antimicrobial resistance is a major global health problem that requires exploration for new natural drug alternatives. This study examines the extraction process, chemical analysis, and assessment of the antimicrobial properties of the volatile oils from Cymbopogon citratus and Ageratum conyzoides. Whole volatile oils were extracted from the two plants by hydrodistillation. The chemical constituents of both are compared by gas chromatography-mass spectrometry (GC-MS). Five bacterial and two fungal strains were chosen for the antimicrobial studies. The cup-plate agar diffusion method was used to test microbial susceptibility to the volatile oils. The oil yield of the two plants was 1.4% for C. citratus and 0.0079% for A. conyzoides. GC-MS analysis indicated that citral is the main ingredient of C. citratus, while A. conyzoides was high in precocene. C. citratus oil exhibited potent broad-spectrum antibacterial activity against in vitro-tested pathogenic bacteria and fungi in a dose-dependent concentration. With a potent antifungal activity. On the other hand, the essential oil of A. conyzoides showed weak performance and hence inhibited only P. aeruginosa and C. albicans at the highest concentration tested (25% w/v) and exhibited a weak effect against the other clinical isolates used in the study. C. citratus volatile oil demonstrated a very good antimicrobial activity and could serve as a good antimicrobial agent against bacterial and fungal infection

The nasal cavity hosts a wide array of organisms. Pathogenic organisms may find access into the sinuses leading to infection. Plasmids, which are small extracellular DNA molecules, play a role by transferring resistance encoded genes among bacteria, facilitating the spread of antibiotic resistance. By investigating the role of plasmid genes in potential treatment failures, the research seeks to broaden our understanding on how plasmids mediate
antibiotic resistance. This knowledge is key for developing effective strategies to combat
sinusitis disease using anti microbialagents.
Methods: The study evaluated forty-three patients from the Ear Nose and Throat Clinic of the University of Benin Teaching Hospital, Benin city. Patient’s data collected were age,gender, alcoholhistory, smokinghistory, medical history. Isolates obtainedwere subjected to antimicrobial susceptibility testing and plasmid curing with acridine orange as the curing agentusingstandardagardiscdiffusionmethod. Results: A total of 58.1% of our study participants were female, and 41.9% were male. Participants aged 16-25 had the highest sinusitis occurrence (27.9%). Nasal discharge was the most encountered symptom across all participants. Staphylococcus aureus dominated in
the nasal cavity of study participants (35.1% aerobic) compared to other organisms isolated. Pseudomonas aeruginosa accounted for the highest abundance (31.3%) under anaerobic condition. Multi-drug resistance was observed in 23.4% and 25% of total aerobic and anaerobic isolates respectively. Resistance to fluoroquinolones was lost post curing in Staphylococcusspp,Klebsiellaspp.
Conclusion: Females were more susceptible to sinusitis with recurrent episodes experienced compared to males. The presence of plasmid-mediated multidrug resistance genes
underscores the need for antibiograms, and rational antibiotics use insinusitis treatment.

This research explored the chemical composition and antimicrobial activity of the essential oil derived from Ocimum basilicum Linn. (Sweet Basil). The oil was obtained through
hydrodistillation using a Clevenger-type apparatus, producing a 0.71% (v/w) average yield of a light-yellow, aromatic extract. Chemical profiling carried out with Gas Chromatography– Mass Spectrometry (GC–MS) revealed nine major constituents, with estragole (46.12%), eucalyptol (16.87%), and linalool (10.45%) as the predominant compounds, supported by smaller amounts of eugenol, thymol, β-caryophyllene, bisabolene, and τ-cadinol. The antimicrobial properties of the oil were assessed using agar well diffusion and minimum inhibitory concentration (MIC) assays against selected bacterial and fungal strains. Results indicated that the oil displayed dose-dependent inhibitory activity, showing marked effects against Staphylococcus aureus (19 mm), Bacillus subtilis (18 mm), Candida albicans (17 mm), and Aspergillus niger (21 mm), while Escherichia coli and Pseudomonas aeruginosa exhibited resistance. The observed antimicrobial efficacy was linked to the synergistic actions of oxygenated monoterpenes and phenylpropanoids in the oil. These findings demonstrate that O. basilicum essential oil exhibits strong antimicrobial potential, especially toward Gram-positive bacterial and fungal organisms, thereby validating its traditional medicinal applications. The dominance of estragole and eucalyptol suggests the Nigerian-grown species belongs to the estragole–eucalyptol chemotype. In summary, the study establishes O. basilicum oil as a viable natural antimicrobial candidate with promising applications in pharmaceutical, nutraceutical, and cosmetic industries, contributing to sustainable strategies against antimicrobial resistance.