Journal of Advances in Microbiology

Phytochemical Profile, Acute Toxicity, and Fluconazole-modulating Antifungal Activity of Stem and Barck Extracts of Adansonia digitata L. (Bombacaceae) against Nakaseomyces glabratus Isolates in Côte d’Ivoire

2026-10-09T12:03:32+00:00

Background &Aim: Nakaseomyces glabratus (formerly Candida glabrata) is an opportunistic yeast associated with invasive candidiasis and reduced susceptibility to azole antifungals. Plant-derived extracts are being investigated as potential modulators of antifungal activity, but evidence depends on the fungal strain, extract composition, and experimental method. This study evaluated the phytochemical profile, safety, in vitro antifungal activity, and interaction with fluconazole of aqueous and hydroethanolic extracts prepared from the stem and root bark of Adansonia digitata against N. glabratus isolates in Côte d’Ivoire.

Materials: Four extracts were evaluated: aqueous stem (EAET) and root (EAER) bark, and hydroethanolic stem (EOHET) and root (EOHER) bark. Antifungal activity was assessed against two N. glabratus strains using agar incorporation and 2% glucose RPMI microdilution. Fluconazole-extract interactions were assessed by checkerboard testing and the fractional inhibitory concentration index (FICI). Acute oral toxicity was assessed after a single 5,000 mg/kg dose in female rats.

Results: Phytochemical screening revealed sterols and polyterpenes, polyphenols, flavonoids, alkaloids, and tannins. Aqueous extracts showed lower MICs than hydroethanolic extracts in the agar-incorporation assay (125 versus 1,000 mg/mL for both strains). Corresponding MFCs were 500 and 1,000 mg/mL, with MFC/MIC ratios of 4 and 1. In combination with extracts, fluconazole MIC decreased from 8 to 4 mg/L for the reference strain and from 4 to 1 mg/L for the clinical isolate. FICI values ranged from 0.52 to 0.83 for the reference strain (additive) and from 0.26 to 0.33 for the clinical isolate (synergistic) under the prespecified thresholds. No mortality or major clinical signs were observed at 5,000 mg/kg; however, ASAT activity was significantly altered in the EOHET group.

Conclusion: Aqueous extracts showed greater inhibitory potency, whereas hydroethanolic extracts showed a lower MFC/MIC ratio. The interaction with fluconazole was isolate-dependent, ranging from additive to synergistic. These preliminary in vitro findings, obtained from two strains, do not establish clinical efficacy or therapeutic applicability. Larger isolate panels, quantitative chemical profiling, mechanistic studies, reproducibility assessment, and appropriately designed in vivo studies are required.

Exploring Growth Promoting and Drought Related Functional Traits of Pink Pigmented Facultative Methylotrophs from Okra (Abelmoschus esculentus L.)

2026-10-09T13:16:24+00:00

Pink-pigmented facultative methylotrophs (PPFMs) are common plant associated bacteria with diverse biochemical traits that may contribute to plant interactions. This study characterised functional variation among 36 PPFM isolates recovered from okra phyllosphere and rhizosphere samples collected in Kerala from March to July 2024 and assessed their in vitro plant growth-promoting (PGP) associated traits and growth under (Polyethylene Glycol) PEG 6000 induced osmotic stress. The isolates were examined for morphology, Gram reaction, oxidase and catalase activity, indole-3-acetic acid (IAA), gibberellic acid (GA), extracellular ammonia and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Twelve PPFM isolates were selected based on their overall PGP-associated profiles across the measured traits and were tested at 0, 10, 20, 30 and 40% (w/v) PEG 6000. IAA ranged from 2.43 to 53.80 µg mL⁻¹ with tryptophan supplementation in the medium and from 0.16 to 42.02 µg mL⁻¹ without tryptophan supplementation. GA ranged from 0.05 to 98.82 µg mL⁻¹, while extracellular ammonia was detected in 22 isolates. ACC deaminase activity varied from 0.77 to 16.60 µmol mL⁻¹. PPFM R5 and PPFM P10 displayed broad PGP profiles, whereas PPFM P25 recorded the highest mean optical density at 600 nm (OD600) at 20 and 30% PEG, with values of 0.97 and 0.95, respectively. Partial 16S rRNA gene sequence analysis identified PPFM R5 as closely related to Methylobacterium brachiatum (99.51% sequence identity) and PPFM P10 as closely related to Methylobacterium radiotolerans (98.33% sequence identity). The findings demonstrate considerable functional heterogeneity among PPFM isolates from okra and indicate that PGP-associated traits and tolerance to PEG 6000induced osmotic stress can vary independently among isolates. These results provide a basis for selecting functionally distinct PPFM isolates for further evaluation as plant associated microbial inoculants.

Kutai Clay Granules for Reducing Escherichia coli and Coliform Bacteria in Hospital Wastewater

2026-10-10T11:04:47+00:00

Aims: This study evaluated the capacity of activated Kutai clay granules to reduce Escherichia coli and coliform bacteria in hospital wastewater and to characterise the clay by particle composition and cation-exchange capacity (CEC).

Study Design: Laboratory experimental study comparing untreated hospital wastewater with four Kutai clay doses.

Place and Duration of Study: Hospital wastewater was obtained from Abdoel Wahab Sjahranie Hospital, Samarinda, Indonesia, and laboratory analyses were performed using facilities associated with Mulawarman University. The study period was not reported in the source manuscript.

Methodology: Activated Kutai clay granules were heated at 121°C for 30 minutes. Four doses (2.5, 5.0, 7.5, and 10.0 g) were separately added to 100 mL of hospital wastewater. Samples were stirred at 2500 rpm for 5 minutes and allowed to settle for 1–3 minutes. E. coli and coliform concentrations were measured using the Most Probable Number (MPN) method. Clay particle composition and CEC were also determined.

Results: Kutai clay contained 59.0% clay, 26.0% silt, and 15.0% fine sand, with a reported CEC of 19.03 meq/100 g. Untreated wastewater contained 1.1 × 10⁵ MPN/100 mL of both E. coli and coliform bacteria. After treatment, all four clay doses produced a reported concentration of 3.0 × 10² MPN/100 mL for both indicators, corresponding to 99.73% removal. No dose-response difference was observed in the reported measurements.

Conclusion: Under the reported laboratory conditions, Kutai clay granules substantially reduced E. coli and coliform concentrations in hospital wastewater. Because all tested doses yielded the same reported endpoint, the lowest dose (2.5 g/100 mL) may warrant further evaluation for treatment efficiency. Replicated experiments, statistical analysis, and physicochemical characterisation are needed before scale-up or routine application.

Prevalence and Epidemiological Distribution of Mycobacterium tuberculosis and Rifampicin-Resistant Tuberculosis Among Patients Attending Selected Health Facilities in South-Western Nigeria

2026-10-14T11:14:59+00:00

Tuberculosis (TB) remains a major public health challenge in Nigeria, with emerging concerns regarding rifampicin-resistant tuberculosis (RR-TB). Geographic variations in Mycobacterium tuberculosis (MTB) prevalence and drug resistance patterns necessitate localised surveillance to inform evidence-based control strategies. This study aimed to determine the prevalence of MTB and rifampicin resistance among presumptive TB patients attending selected health facilities in south-western Nigeria, and to describe the epidemiological distribution across demographic variables. A cross-sectional, laboratory-based study was conducted among 324 presumptive TB patients recruited from health facilities in Osun, Oyo, and Lagos States. Sputum specimens were analysed using the Xpert MTB/RIF assay. Data were analysed using SPSS, with frequencies, percentages, and chi-square tests employed to examine associations between demographic variables and MTB detection. Statistical significance was set at p < 0.05. Overall MTB prevalence was 24.7% (80/324), with state-specific prevalence of 26.6% in Osun, 23.1% in Oyo, and 15.4% in Lagos. Among MTB-positive cases, 38.8% (31/80) exhibited rifampicin resistance. MTB-positive cases were equally distributed between males and females (50.0% each). The 20–29 and 30–39 years age groups accounted for 56.3% of MTB-positive cases. Artisans and traders together constituted 62.5% of MTB-positive participants. Among RR-TB cases, males represented 61.3%, and Osun State accounted for 67.7%. No statistically significant associations were observed between MTB detection and age (p = 0.081) or sex (p = 0.178). The findings indicate a substantial burden of MTB (24.7%) and an alarmingly high prevalence of rifampicin resistance (38.8%) in south-western Nigeria, exceeding global and several regional estimates. This study had several limitations. The unequal state-specific sample sizes limited the precision of comparisons, particularly in Oyo and Lagos States. Second, the facility-based design limits generalisation to the wider population. Finally, the cross-sectional design limits causal interpretation of the findings. These data emphasise the urgent need for enhanced diagnostic capacity, strengthened drug-resistance surveillance, and targeted interventions to mitigate transmission and improve treatment outcomes.

Evaluation of Antagonistic Properties of Indigenous Biological Control Agents against Fusarium oxysporum, Causal Agent of Tomato Vascular Wilt in Burkina Faso

2026-10-14T11:26:38+00:00

This study aims to contribute to the improvement of plant health through the use of beneficial microorganisms, isolated from soil samples in Burkina Faso to control Fusarium oxysporum. The suspension dilution method was used for isolation from soil samples. King's B and LBA media were used to isolate bacteria of the Pseudomonas and Bacillus species, respectively. The antagonistic potential of the different colonies isolated was evaluated using the co-culture method and in vivo in vegetation pots. Two tests were carried out in the greenhouse using a completely randomised block design. Seedling treatment was carried out by immersing their roots in the bacterial solution beforehand. The results revealed the presence of bacteria with antagonistic properties. Identification of the bacteria based on sequencing of the 16S region of ribosomal DNA, revealed that they belonged to three genera composed of Bacillus (B. subtilis, B. amyloliquefasciens and B. thuringiensis), Pseudomonas (P. fluorescens) and Burkholderia (Burkholderia sp.). The strains exhibited antagonistic activity, significantly inhibiting the mycelial growth of F. oxysporum, F. duofalcatisporum and E. sorghinum, except L. theobromae. The results indicated that the soil treatments provided control of tomato vascular wilt. The rhizobacteria tested were more effective (with protection indices (PI) ranging from 87.1% to 96.1%) when applied a week before the pathogen in the soil than with seedling treatments where the pathogen and antagonists were applied at the same time (PI ranging from 54% to 77%). In addition, all bacteria promoted the growth of tomato plants irrespective of treatment. Finally, they are not only potential biocontrol agents against tomato vascular wilt, but also also contributed to seedling growth. These antagonistic bacteria could be proposed as microbial biopesticides for a biological control strategy against Fusarium wilt.

Impact of Public Health and Occurrence of Multidrug-resistant Bacteria Isolated from Lettuce (Lactuca sativa) Sold in Kpirikpiri Market, Ebonyi State, Nigeria

2026-10-16T14:19:32+00:00

Vegetables, including lettuce (Lactuca sativa), can be exposed to pathogenic microorganisms during production, transportation, handling, processing, and selling through handling by vendors and consumers. Microbial contamination of vegetables could result from the use of animal waste containing antibiotic-resistant bacteria as fertiliser to enhance plant growth. The study aimed to assess the impact on public health and the occurrence of multidrug-resistant bacteria isolated from lettuce (Lactuca sativa) sold in Kpirikpiri Market, Ebonyi State, Nigeria. Twenty (20) lettuce samples collected from Kpirikpiri Market in Ebonyi Local Government Area were analysed bacteriologically using standard microbiological procedures. The bacterial isolates were subjected to antibiotic susceptibility testing using the Kirby–Bauer method. The bacterial counts showed a total aerobic count within the range of 9.4x 10^-4–1.1 x 10^-4cfu/g, with a mean value of 2.96 x 10^-4cfu/g. Morphological and biochemical characterisation of the isolates identified six bacterial groups (Escherichia coli, Pseudomonas species, Salmonella species, Shigella species, Staphylococcus aureus and Proteus species) were identified from the samples. The percentage occurrence of isolates showed that Staphylococcus aureus and Escherichia coli each accounted for 3 (18.75%); Proteus species accounted for 4 (25%), while Salmonella species, Shigella species, Pseudomonas species each accounted for 2 (12.5%). Antibiotic susceptibility testing showed that Pseudomonas species were 100% resistant, Proteus species and Shigella species were 90% resistant, Escherichia coli and Salmonella species were 80% resistant, while Staphylococcus aureus showed 70% resistance to the tested antibiotics. The six bacterial isolates had an average MARI value of 0.57, indicating resistance to five different classes of antibiotics. The findings suggest that lettuce may harbour potentially pathogenic bacteria with resistance to several tested antibiotics. Concerted efforts are therefore warranted to monitor the use of animal dung as fertiliser in vegetable cultivation. Furthermore, appropriate processing and improved market sanitation may help to reduce such contamination.

Helicobacter pylori Infection among Patients Seen at Federal Medical Centre Asaba, Delta State: A Comparison of Serological and Faecal Antigen Testing Methods

2026-10-22T05:33:37+00:00

Background: Helicobacter pylori is a Gram-negative, microaerophilic bacterium that has been established as the primary aetiological agent responsible for chronic gastritis and peptic ulcer disease.

Aim: This study aimed to compare the diagnostic performance of serological testing with faecal antigen testing for the diagnosis of H. pylori infection in subjects attending Federal Medical Centre, Asaba. Accurate diagnosis of infection is important for effective management and control.

Methodology: A comparison of the performance of two diagnostic test methods, serology and stool antigen testing, for Helicobacter pylori infection was conducted among 397 patients using a prospective cross-sectional study design. Blood and fresh stool samples were collected from eligible patients after consent. Serum samples were tested for H. pylori antibodies using a serological method, whereas stool samples were tested for H. pylori antigen. The stool antigen method was used as the reference method for assessing the diagnostic performance of serology. Sensitivity, specificity, positive predictive value, negative predictive value, and the level of agreement between the two methods were also analysed.

Results: The age distribution of participants was similar across genders, with a mean age of approximately 38 years. Serology and stool antigen testing showed similar positivity rates of 43.07% and 42.57%, respectively. Using stool antigen testing as the reference method, the serological test showed a sensitivity of 93.5% and specificity of 94.3%, with a positive predictive value (PPV) of 92.4% and a negative predictive value (NPV) of 95.1%. However, Cohen’s kappa analysis showed 0.877 (95% CI:0.83-0.92) indicating almost perfect agreement.

Conclusion: The study demonstrated that the serological method showed high diagnostic performance compared with stool antigen testing and may be useful as a screening method for H. pylori infection when the serology result is negative. However, stool antigen testing remains useful for confirming active infection because it detects active infection rather than past exposure.

Effect of Azotobacter and Phosphate Solubilizing Bacteria (PSB) on Growth and Yield of Spinach (Spinacia oleracea L.)

2026-10-22T13:10:23+00:00

Spinach (Spinacia oleracea L.) is an important leafy vegetable whose growth and productivity depend on adequate nutrient availability. The use of beneficial microorganisms, particularly Azotobacter and phosphate-solubilising bacteria (PSB), offers a potential approach to improving nutrient availability and reducing dependence on chemical fertilisers. However, the effectiveness of native bacterial isolates under reduced nitrogen and phosphorus fertiliser application requires further field evaluation. The present investigation was undertaken to isolate, characterise and select efficient native Azotobacter and phosphate-solubilising bacteria (PSB) from the rhizosphere of spinach and to evaluate their individual and combined effects with different fertiliser levels on the growth, yield and quality of spinach (Spinacia oleracea L.). Six Azotobacter and four PSB isolates were obtained from sixteen rhizospheric soil samples collected from Kolhapur district. Based on nitrogen-fixing ability and phosphate-solubilising efficiency, Azotobacter isolate-III (11.35 mg N ml⁻¹) and PSB-I (solubilization index 4.0) were selected for field evaluation. The field experiment was conducted during rabi 2025–26 at the Instructional-cum-Research Farm, RCSM Government College of Agriculture, Kolhapur. Among the treatments, T₇ (Azotobacter + PSB + 75% N and P₂O₅ + recommended dose of K₂O) recorded superior performance. The minimum number of days to germination (4.0 days) and the maximum germination percentage (91.33%) were recorded under treatment T₇. Plant heights under T₇were 31.43, 25.93 and 22.13 cm, leaf areas were 132.00, 105.33 and 103.33 cm², total number of leaves was 43.33, fresh weights were 36.00, 33.56 and 26.28 g plant⁻¹ and dry weights were 18.93, 18.41 and 15.77 g per 100 g fresh weight during the first, second and third cuttings, respectively. T₇ also recorded the highest total yield of 18.96 t ha⁻¹, ascorbic acid content of 62.83 mg 100 g⁻¹ and chlorophyll content of 2.27 mg g⁻¹. Root length reached 28.33 cm under T7. The findings demonstrated that combined application of native Azotobacter and PSB with 75% N and P₂O₅ and recommended K₂O improved growth, biomass, yield and quality of spinach and showed potential for efficient nutrient management with reduced N and P fertiliser use.

Prevalence and Virulence Potentials of Staphylococcus aureus and Escherichia coli Associated with Public Toilets in Port Harcourt Metropolis, Nigeria

2026-10-23T11:33:13+00:00

Background and Aims: Shared public toilets may harbour bacteria of relevance to environmental hygiene. The study determined the prevalence and virulence potentials of S. aureus and E. coli in samples collected from toilet bowls and seats in selected public facilities in Port Harcourt Metropolis, Nigeria.

Methodology: Water and swab samples were collected from public toilets in banks, secondary schools, shopping malls, hospitals and universities, and these samples were examined. Samples were cultured, and presumptive isolates were identified by colony morphology, Gram staining and biochemical tests. Prevalence, biofilm formation and the ability to lyse red blood cells were determined.

Results: Among the 186 isolates reported, the overall prevalence was 15.5% for S. aureus and 9.4% for E. coli. Both organisms were reported more frequently in toilet bowls than on seats: S. aureus, 45.6% and 23.3%, and E. coli, 36.7% and 10.0%, respectively. Bowl contamination varied by location; the prevalence of S. aureus ranged from 44.4% in malls to 66.7% in secondary schools, while that of E. coli ranged from 22.2% in banks and malls to 61.1% in secondary schools. The distribution of hemolysis patterns among the bacterial isolates showed that among the 28 S. aureus isolates, β-haemolysis was observed in 13 (46%) isolates, followed by α-haemolysis in 10 (36%) isolates, while γ-haemolysis was the least common, occurring in 5 (18%) isolates. Among the E. coli isolates, γ-haemolysis was predominant, accounting for 13 (76%). The biofilm production results for S. aureus showed that 22 (79%) isolates were positive, while 6 (21%) were negative. Among the E. coli isolates, 6 (65%) were biofilm producers and 11 (35%) were non-biofilm producers.

Conclusion: The study indicates that frequently used public toilet facilities can serve as reservoirs for bacterial contamination and potential transmission because the recovered isolates are of potential public health importance. Routine cleaning and disinfection, hand hygiene promotion, and periodic microbiological surveillance are warranted.