Journal of Advances in Microbiology

Next-generation Diagnostics for Silkworm Diseases: A Critical Narrative Review of Molecular Markers, Biosensors, Imaging and Artificial Intelligence

Rubi Sut, K. Pramod, Pulak Rabha, Bhaswati Saikia, Priyangana Chetia — Tue, 27 Oct 2026 00:00:00 +0000

Diseases of the domesticated silkworm, Bombyx mori, remain a principal cause of cocoon crop loss, and the inspection systems that protect silkworm egg production still depend heavily on light microscopy and visible symptoms. During the past decade, nucleic-acid amplification, clustered regularly interspaced short palindromic repeats-based detection, electrochemical and lateral-flow biosensing, vibrational spectroscopy, quantitative imaging and machine learning have each been proposed as faster or more sensitive alternatives. Existing reviews have generally treated these technologies separately, and none has judged them against an explicit framework of intended use, reference-standard quality and field validation. This critical narrative review integrates peer-reviewed evidence on diagnostics for microsporidian pébrine, nucleopolyhedrovirus grasserie, the viral and bacterial flacherie complex and fungal muscardine, drawing on international bibliographic databases, regional Japanese and Korean scholarly platforms and citation tracking. The evidence indicates that quantitative polymerase chain reaction is the only modality evaluated at the scale of routine egg-production inspection, where it agreed closely with female moth microscopy on positive samples while detecting additional infections that microscopy missed. Isothermal and clustered regularly interspaced short palindromic repeats-based assays have reached high analytical sensitivity and increasingly portable formats, but most evaluations rely on plasmids, purified genomic DNA or experimentally infected larvae rather than field lots. Electrochemical biosensors report very low detection limits in buffered or spiked samples, yet independent replication and comparison with reference methods are scarce. Spectroscopic and image-based classifiers frequently report accuracies above ninety per cent, although small single-site datasets, visually assigned labels and absent external validation limit confidence in their transferability. Pathogen diversity, latent and mixed infections, and the imperfect nature of microscopy as a reference standard affect every modality. The available evidence supports qualified adoption of quantitative and isothermal nucleic-acid assays for seed inspection, whereas biosensors and artificial intelligence remain at the proof-of-concept stage. Progress now depends on fitness-for-purpose validation, multi-site sample panels with molecularly confirmed labels, lot-level sampling designs and tiered diagnostic architectures that link non-invasive screening to confirmatory testing.

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

Fri, 09 Oct 2026 00:00:00 +0000

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.)

Fri, 09 Oct 2026 00:00:00 +0000

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

Sat, 10 Oct 2026 00:00:00 +0000

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

Wed, 14 Oct 2026 00:00:00 +0000

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

Wed, 14 Oct 2026 00:00:00 +0000

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

Fri, 16 Oct 2026 00:00:00 +0000

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

Thu, 22 Oct 2026 00:00:00 +0000

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.)

S. S. Jadhav, D. P. Deshmukh, R. A. Karande, S. J. Waghmare, S. B. Mahajan — Thu, 22 Oct 2026 00:00:00 +0000

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

O. Ejims-Enwukwe, L. O. Amadi, T. Sampson, C. J. Ugboma — Fri, 23 Oct 2026 00:00:00 +0000

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.

Identification and Partial Genome Characterization of Mungbean Yellow Mosaic India Virus Infecting Soybean via Rolling Circle Amplification and Restriction-based Cloning

Vineeth Vijayan, Venkatesh Iddumu, Ainmisha — Wed, 28 Oct 2026 00:00:00 +0000

Background: Yellow mosaic disease (YMD) is one of the most economically damaging constraints on soybean (Glycine max L.) cultivation across South and Southeast Asia. It is caused by whitefly (Bemisia tabaci)-transmitted, bipartite begomoviruses belonging to the family Geminiviridae. In the present study, a soybean plant showing typical bright yellow mosaic symptoms was investigated to identify and molecularly characterise the causal begomovirus.

Methods: Total genomic DNA extracted from symptomatic leaf tissue was subjected to rolling circle amplification (RCA) using bacteriophage phi29 DNA polymerase. The resulting high-molecular-weight concatemeric product was digested with four restriction endonucleases (HindIII, EcoRI, NotI and BamHI). The HindIII fragment, which produced the sharpest and most intense band, was cloned into the HindIII site of dephosphorylated pUC18 vector. Recombinant clones were screened by colony PCR using component-specific primers. Plasmid DNA from positive clones was subjected to double digestion with HindIII and BglI to confirm full-length insertion, followed by sequencing of the cloned insert. The resulting sequence was analysed using BLASTn against the NCBI nucleotide database, and viral identity was assigned using pairwise BLAST identity comparisons.

Results: Each restriction enzyme released a single, unit-length fragment of approximately 2.7 kb, consistent with a monopartite circular ssDNA genome component. Colony PCR amplified the expected ~508 bp diagnostic product, confirming successful cloning. Double digestion with HindIII and BglI released the ~2.7 kb insert from the 1.5 kb and 1.2 kb vector backbone fragments, confirming full-length insertion. Sequencing yielded a partial genome sequence of ~2.5 kb, which showed 96–99% nucleotide sequence identity with DNA-A components of Mungbean yellow mosaic India virus (MYMIV) isolates reported from multiple geographic regions of India. As the recovered sequence represented a partial rather than a complete DNA-A component, phylogenetic reconstruction was not performed.

Conclusion: These results confirm that MYMIV, rather than the closely related Mungbean yellow mosaic virus (MYMV), is associated with yellow mosaic disease in the soybean accession examined. The study demonstrates a straightforward RCA–RFLP cloning pipeline for recovering full-length begomoviral genome components directly from field-infected tissue without prior knowledge of the infecting strain.

Screening of Endophytic Bacteria from Azadirachta indica and Tridax procumbens for Waste-Engine-Oil-Associated Redox Activity: A DCPIP and Qualitative GC–MS Study

S. H. Kamble, A. Z. Durugkar, V. S. Sangatekar, K. S. Mudake — Thu, 29 Oct 2026 00:00:00 +0000

Background: Plant-associated endophytic bacteria are a potential source of microorganisms exhibiting oxidative responses to petroleum-derived substrates, but screening assays alone do not establish the mass of oil removed.

Objective: To isolate bacterial endophytes from Azadirachta indica and Tridax procumbens, compare waste-engine-oil-associated redox responses, examine single-factor culture conditions, and describe qualitative gas chromatography–mass spectrometry (GC–MS) profiles.

Methods: Twelve bacterial isolates were recovered, of which two were selected for morphological and biochemical characterisation and screening with the redox dye 2,6-dichlorophenolindophenol (DCPIP). The selected isolates were examined on mineral-salt agar containing waste engine oil. Isolate I underwent 16S rRNA gene analysis and carbon-source, temperature, and pH comparisons; treated and untreated oil samples were examined by GC–MS.

Results: Within 72 h, the initial and final DCPIP absorbances were 0.332 and 0.047 for isolate I and 0.531 and 0.107 for isolate II, corresponding to unadjusted decreases in dye absorbance of 85.84% and 79.85%, respectively. These values are not percentages of oil degraded. Isolate I showed 99.86% sequence similarity to Kytococcus sedentarius. The single-factor tables ranked glucose, ambient incubation and pH 7 highest on the reported assay-response index. Comparative GC–MS peak lists showed differing relative profiles and tentative oxygenated-compound annotations, without demonstrating absolute compound loss or metabolic provenance. The final uninoculated-control value and assay-level replication were not documented, preventing attribution of these optical changes exclusively to oil-associated microbial metabolism.

Conclusion: The observations justify further testing of a neem-associated isolate closely related to K. sedentarius as a candidate for hydrocarbon-related microbial activity. The extent of waste-engine-oil biodegradation, mineralisation, and environmental effectiveness remains undetermined. The experiments are exploratory and do not establish statistically supported differences between isolates.

Molecular Detection of Esp and qnrA Genes in Biofilm-Producing Multidrug-Resistant Proteus mirabilis from Catheter-Associated Urinary Tract Infections in Bauchi Metropolis, Nigeria

Thu, 29 Oct 2026 00:00:00 +0000

Background and Aims: Catheter-associated urinary tract infections may involve multidrug-resistant (MDR) Proteus mirabilis capable of biofilm formation. Molecular data on such isolates in Bauchi Metropolis, Nigeria, are limited. This study investigated antimicrobial resistance, biofilm formation and PCR detection of esp-targeted and qnrA amplicons in P. mirabilis from catheterised patients.

Methods: In this cross-sectional, laboratory-based study, 227 urine specimens were collected from catheterised inpatients at Abubakar Tafawa Balewa University Teaching Hospital (n = 130) and Specialist Hospital Bauchi (n = 97) between January and July 2025. Isolates were identified using culture characteristics, microscopy and biochemical tests. Disc diffusion was used for antimicrobial susceptibility testing, and the tube method was used to assess biofilm formation. Five MDR, biofilm-producing isolates underwent conventional PCR.

Results: Among 173 microbial isolates, 12 (6.9%) were P. mirabilis (six each from ATBUTH and SHB). A higher proportion of isolates was recovered from female patients (58.3%) and from patients aged ≥60 years (83.3%), with more isolates recovered following longer durations of catheterisation (≥30 days: 33.3%). The isolates showed high resistance to amoxicillin (66.7-100%), cefotaxime (83.3-100%), ceftazidime (66.7-83.3%), cotrimoxazole (66.7-100%), and fluoroquinolones (66.6-100%) based on hospital-specific denominators (ATBUTH n=6, SHB n=6). Among the five biofilm-producing MDR isolates subjected to molecular analysis, Esp was detected in 5/5 (100%) and qnrA in 4/5 (80.0%). These results apply only to the tested subset and cannot be generalised to all 12 P. mirabilis isolates

Conclusion: Multidrug-resistant, biofilm-producing P. mirabilis with Esp-targeted and qnrA amplicons were detected among catheterised patients in Bauchi. These findings underscore the need for strengthened catheter care, antimicrobial stewardship and continued surveillance to control CAUTIs.

GC-MS Profiling and Solvent-dependent in Vitro Antibacterial Activity of Zingiber officinale Roscoe Rhizome Extracts against Clinical Bacterial Isolates

Fri, 30 Oct 2026 00:00:00 +0000

The global rise in antimicrobial resistance among clinically significant bacteria has intensified interest in plant-derived antibacterial agents. Zingiber officinale Roscoe (ginger) is a widely used medicinal spice whose rhizome extracts have long been associated with antimicrobial activity, but the influence of extraction solvent polarity on this activity against defined clinical isolates remains incompletely characterised. This study characterised the chemical profile of a crude Zingiber officinale rhizome extract and compared the antibacterial activity of five solvent extracts against four clinical isolates. The chemical composition of a crude ginger rhizome extract was profiled by gas chromatography-mass spectrometry (GC-MS). Antibacterial activity of five solvent extracts (aqueous, ethanolic, hexane, acetone, and ethyl acetate) was evaluated by agar well diffusion against four hospital-sourced clinical isolates (Klebsiella pneumoniae, Proteus mirabilis, Staphylococcus aureus, and Streptococcus pneumoniae) across a concentration gradient (12.5-100 mg/mL). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each solvent-isolate combination, and the MBC/MIC ratio was used to classify bactericidal versus bacteriostatic activity. GC-MS analysis of the crude extract resolved twenty-one reliably identified compounds, dominated by long-chain aliphatic hydrocarbons, fatty acids (n-hexadecanoic acid, 9-octadecenoic acid), and the triterpene squalene. All five solvent extracts produced concentration-dependent zones of inhibition against all isolates, with hexane and ethyl acetate extracts generally producing the largest zones at 100 mg/mL. In Table 5, the ethanolic extract had the lowest reported MIC for P. mirabilis (16.66 ± 0.95 mg/mL) and S. aureus (8.32 ± 0.67 mg/mL), whereas acetone was numerically lowest for K. pneumoniae (30.70 ± 2.90 mg/mL) and S. pneumoniae (8.13 ± 0.92 mg/mL). The reported antibacterial responses varied with extraction solvent and test isolate.

Acidification, Presumptive Microbial Dynamics, and Illustrative Dose–response Modelling in Two Tepache Fermentations: An Exploratory Two-Vessel Case Comparison

L. C. Nnodim, C. Njoku, S. Atah, P. I. Lawrence, P. K. Mballey, C. J. Onwuachu — Sat, 31 Oct 2026 00:00:00 +0000

Acidification is widely associated with microbial control during spontaneous fermentation, but its relation to culture-dependent indicators is affected by microbial identity, matrix composition and process conditions. This exploratory case comparison followed one Traditional tepache preparation containing cinnamon, cloves and star anise and one Modified preparation containing Hibiscus sabdariffa, Xylopia aethiopica, Monodora myristica, Piper guineense and African lemon. Each formulation was prepared in a single vessel and sampled at 0, 24, 48 and 72 h; duplicate laboratory determinations were analytical rather than independent fermentation replicates. Measured pH and operational chemical assays were described alongside presumptive culture-group counts. Conditional Beta-Poisson scenarios and primary kinetic fits were examined only as mathematical illustrations. At 72 h, pH was 2.875 in the Traditional vessel and 2.775 in the Modified vessel. The corresponding titrimetric outputs labelled lactic acid were 13.050 and 18.675 g/L, respectively, but species-specific acid identity was not established. In the Modified vessel, presumptive thermotolerant coliform-like counts changed from 5.150 log10 CFU/mL at 0 h to 4.300 at 24 h and 5.400 at 48 h, followed by a negative enrichment result at 72 h. In the Traditional vessel, enrichment was negative from 24 h onward. Salmonella-like colonies were observed initially without confirmatory identification. Monotonic microbial models could not represent the Modified vessel's count reversal, and short-term extrapolation did not reproduce its 48-h scenario output. In these two particular preparations, declining pH did not consistently parallel culturable coliform-like counts. Neither formulation effects nor product safety can be established without independent fermentations, species-selective chemical measurements and confirmatory microbiological testing.

Antibacterial Effects of Two Banana Varieties: A Comparative Study of Methanolic and Ethanolic Leaf Extracts of Banana Varieties against Selective Pathogenic Bacteria

Tue, 03 Nov 2026 00:00:00 +0000

Background: Increasing antimicrobial resistance has encouraged the investigation of plant-derived antibacterial agents. Banana leaves, traditionally used for food preparation and serving, may contain constituents with antimicrobial activity, although comparative evidence for different cultivars remains limited.

Aim: To compare the antibacterial effects of methanolic and ethanolic extracts of dried leaves from the grand naine and agnishwar banana cultivars against selected pathogenic bacteria.

Method: Dried banana leaves were extracted separately using methanol and ethanol, and the resulting extracts were prepared at 100 mg/mL. Antibacterial activity was assessed using the disc diffusion method against Staphylococcus aureus (ATCC 25953), Escherichia coli (ATCC 25922) and Salmonella typhi (ATCC 14028). Gentamicin and the corresponding solvents served as positive and negative controls, respectively. Assays were performed in triplicate, and inhibition zones were expressed as mean ± standard deviation.

Results: Grand naine methanolic extract inhibited all three organisms, producing inhibition zones of 8 ± 0.50, 7 ± 0.30 and 9 ± 0.57 mm, respectively. Its ethanolic extract inhibited only S. typhi (8 ± 0.40 mm). Agnishwar methanolic and ethanolic extracts inhibited only S. aureus, producing inhibition zones of 7 ± 0.35 and 7 ± 0.30 mm, respectively. Gentamicin produced larger inhibition zones (19–24 mm), whereas negative controls showed no inhibition.

Conclusion: Antibacterial activity varied according to banana cultivar, extraction solvent and bacterial species. Grand naine methanolic extract exhibited the broadest antibacterial activity, although all active extracts were less effective than gentamicin under the experimental conditions.

Resistance of Avian Salmonella spp. Strains to Critical Antibiotics: The Case of Quails at the SAP in La Mé, Côte d’Ivoire

Tue, 03 Nov 2026 00:00:00 +0000

Background and Aims: Contamination of poultry products with bacteria of the genus Salmonella is a major public health problem worldwide. The aim of this study was to assess the prevalence of Salmonella spp. in faecal samples from Japanese quails (Coturnix japonica) reared on a commercial farm in the La Mé region of Côte d’Ivoire, to determine the antibiotic susceptibility profile of the isolates, and to characterise their genetic profiles by detecting the aminoglycoside resistance gene aac(6′)-Ib.

Methodology: A total of 18 faecal samples were collected from different batches of quails, grouped according to age. Strain isolation was carried out in accordance with ISO 6579-1:2017. The isolates were identified using conventional bacteriological methods and then subjected to antibiotic susceptibility testing using the Mueller-Hinton agar diffusion method, in accordance with EUCAST-CASFM recommendations. The gentamicin-resistant strains were then analysed by PCR to detect the aac(6′)-Ib gene.

Result: A prevalence of 61.11 % of Salmonella spp. was observed. This prevalence varied across age groups, but no statistically significant difference was observed (p = 0.49). All isolated strains were resistant to colistin (100 %); 54.54 % were resistant to Augmentin, 36.36 % to gentamicin, 27.27 % to cefotaxime and cefixime, 18.2 % to norfloxacin, and 9.09 % to ceftriaxone. Three strains exhibited a multidrug-resistance profile involving three families of antibiotics. However, none of the strains analysed by PCR harboured the aac(6′)-Ib gene.

Conclusion: This study highlights the circulation of multidrug-resistant Salmonella strains in Japanese quail farms in Côte d’Ivoire, suggesting that quails may act as potential reservoirs for the transmission of antibiotic-resistant pathogens to humans via the food chain. The absence of the aac(6′)-Ib gene suggests that other genetic mechanisms may explain the observed resistance to aminoglycosides. The findings indicate a need to establish continuous surveillance of antibiotic resistance and to ensure the prudent use of antibiotics in poultry production.

Optimizing the Carbon and Nitrogen Concentrations and Ratio for the Growth of Bacterial Consortia-based Biofertilizers

S. Ahmed, J. N. Bhakta — Tue, 03 Nov 2026 00:00:00 +0000

The reliance on synthetic agrochemicals has contributed to soil degradation, highlighting the need for sustainable, cost-effective alternatives. Microbial biofertilisers containing beneficial bacteria present an effective solution for enhancing nutrient availability and supporting agricultural productivity. However, their performance is significantly influenced by nutritional conditions, specifically the carbon-to-nitrogen (C/N) ratio, making its optimisation crucial for effective bacterial growth and biofertiliser development. The objective of this study was to optimise carbon (C) and nitrogen (N) concentrations and their ratio to maximise the growth of bacterial consortia-based biofertilizers. Nutrient-specific bacterial consortia comprising nitrogen-fixing bacteria (NFB_RS), phosphate-solubilising bacteria (PSB_SS) and potassium-solubilising bacteria (KSB_SS) derived from biowaste organic resources were obtained from the present laboratory and cultivated in batch culture experiments. Batch culture experiments were conducted to evaluate the growth dynamics of the NFB_RS, PSB_{SS and} KSB_SSconsortia inoculated in nutrient broth across various carbon concentrations (3, 5, 7, 11, 15, 19, 27, and 35 g/L), nitrogen concentrations (1.06, 1.75, 2.45, 3.84, 5.23, 6.62, 8.01, 9.4 g/L), and initial C:N ratios (3:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 40:1). Growth kinetics were quantified by measuring OD₆₀₀ over 24 h and specific growth rates were calculated during the exponential growth phase. The growth of NFB_RS, PSB_SS and KSB_SS consortia ranged from 0.009 to 1.828 OD, 0.017 to 1.861 OD, 0.025 to 1.756 OD in different C concentrations, 0.02 to 1.828 OD, 0.02 to 1.820 OD, 0.023 to 1.802 OD in various N concentrations, 0.01 to 1.828 OD, 0.02 to 1.850 OD, 0.011 to 1.802 OD in various carbon to nitrogen ratios, respectively. Optimal C concentrations were identified at 15 g/L for the PSB_SS consortium (7.35X), at 11 g/L for NFB_RS (7.76X) and the KSB_SS (6.33X) consortium. Peak proliferation of the bacterial consortia was found at 2.45 g/L for the PSB_SS (7.61X) and KSB_SS (7.85X) consortia, and at an N concentration of 5.23 g/L for NFB_RS (8.03X). The NFB_RS, PSB_{SS and} KSB_SSconsortia showed 8.03X, 7.64X, 7.85X the highest growth increments at a 25:1 C/N ratio compared with the remaining ratios. The findings indicate that C and N concentrations and their ratio significantly influence the growth kinetics and functional efficiency of the consortia. The study concluded that optimised C and N concentrations and their ratio for the maximum growth of bacterial consortia can provide a practical and environmentally friendly method to enhance soil fertility and productivity through improved nutrient solubilisation and cycling.

Molecular Identification of Salmonella in Poultry and Humans in Daloa, Côte d’Ivoire: PCR Detection and Confirmation by invA Gene Sequencing

Wed, 04 Nov 2026 00:00:00 +0000

Background: Molecular documentation of Salmonella isolates from poultry and human sources in Daloa, Côte d’Ivoire, remains limited. This study examined selected isolates using culture-based methods, PCR and sequence analysis.

Aims: To detect the invA gene in isolates of poultry and human origin and assess the similarity of amplified sequences to GenBank references.

Study Design and Methods: A descriptive cross-sectional study was conducted from March to April 2026. Fifty poultry faecal samples were collected at Lobia Market, and three human clinical isolates were obtained from a hospital microbiology laboratory. Presumptive poultry isolates were selected following microbiological enrichment and culture on Hektoen agar. Selected bacterial cultures underwent invA-targeted PCR, Sanger sequencing and BLASTn comparison with reference sequences.

Results: Of the 50 poultry samples, 37 showed bacterial growth on Hektoen agar, and 29 yielded presumptive Salmonella isolates. All 29 selected poultry isolates and three human isolates were PCR-positive (32/32; 100%). Thirty-two sequences were analysed; their lengths ranged from 181 to 223 bp, and nucleotide identities ranged from 95.68% to 99.52%. The 100% positivity refers only to the selected cultures and does not estimate infection prevalence in poultry or humans.

Conclusion: Combined PCR and sequence comparisons supported molecular identification of the investigated isolates. Short invA fragments did not permit serovar identification or establish transmission between poultry and humans. The findings provide local evidence relevant to further One Health surveillance.

Diversity and Salinity Tolerance of Indigenous Bradyrhizobium japonicum Isolates Recovered from Saline Areas

Thu, 12 Nov 2026 00:00:00 +0000

Soil salinity can restrict soybean production and the activity of beneficial nitrogen-fixing rhizobia. This study investigated the recovery, phenotypic characteristics and in vitro salinity tolerance of indigenous Bradyrhizobium japonicum isolates from salt-affected soybean-growing areas of Sangli and Kolhapur districts, Maharashtra, India. Twenty-five soybean root nodule and rhizosphere soil samples were processed, yielding 15 isolates, equivalent to a recovery frequency of 60%. Four selected isolates (Iso-7, Iso-9, Iso-11 and Iso-21) were screened on yeast extract mannitol agar containing 2–10% NaCl. The highest NaCl concentrations supporting growth were 8% for Iso-7, 6% for Iso-21, 4% for Iso-9 and 2% for Iso-11. None grew at 10% NaCl. Only Iso-7 exhibited detectable phosphate solubilisation, producing a 4.5 mm halo, while potassium solubilisation was not detected in any of the four isolates. All four produced hydrogen cyanide; ammonia production was strong in Iso-7, weak in Iso-21 and undetectable in Iso-9 and Iso-11. All four isolates tested positive for catalase, oxidase and starch hydrolysis and negative for indole production, gelatin liquefaction and methyl red reactions. Nitrate reduction varied among isolates. Their cells were Gram-negative and rod-shaped. These findings identify Iso-7 as the most salt-tolerant of the selected isolates and a candidate for subsequent confirmation of identity, symbiotic performance and evaluation under saline growing conditions.

Shotgun Metagenomics of Multi-Kingdom Microbial Adaptation in Sponge Iron Industry-contaminated Soil

Kajari Roy, Palash Pan, Nandan Bhattacharyya, Neeta Shweta Kerketta — Fri, 13 Nov 2026 00:00:00 +0000

Background: Sponge iron industries release heavy metals and other industrial pollutants that can alter soil physicochemical properties and disrupt native microbial communities. These changes may influence microbial diversity, ecological interactions and functional processes. However, the combined diversity and functional adaptation of bacterial, fungal and viral communities in sponge iron industry-contaminated soils remain insufficiently characterised, highlighting the need for an integrated metagenomic investigation.

Aims: To investigate the taxonomic composition, functional potential, and multi-kingdom ecological adaptation of microbial communities in sponge iron industry-impacted soil using whole-genome shotgun metagenomic sequencing, with a focus on identifying microbial taxa and metabolic pathways associated with tolerance to heavy-metal stress and ecological resilience.

Study Design: An observational, cross-sectional, culture-independent metagenomic study integrating physicochemical characterisation, whole-genome shotgun sequencing, and bioinformatics analyses.

Place and Duration of Study: Soil affected by the sponge iron industry in Barjora, West Bengal, India. Laboratory investigations, sequencing, and computational analyses were conducted during the study period.

Methodology: Soil physicochemical properties and concentrations of heavy metals, including Fe, Pb, Cd, and As, were assessed. Illumina whole-genome shotgun sequencing generated approximately 51.199 million raw reads, with 44.257 million cleaned reads reported after quality filtering. Bacterial, fungal, and viral communities were characterised through taxonomic profiling. Functional annotation was performed using KEGG Orthology (KO), Enzyme Commission (EC), and Pfam databases to investigate metabolic pathways, functional enrichment, and microbial diversity.

Results: Bacterial communities were dominated by Proteobacteria (58.78%) and Actinobacteria (21.32%), whereas Acidobacteria accounted for only 0.86%. Ascomycota dominated the fungal communities (87.49%), particularly Thermothielavioides terrestris and Thermothelomyces thermophilus. Viral communities were predominantly represented by Caudovirales bacteriophages, including Siphoviridae and Myoviridae. Functional annotation revealed enrichment of fatty acid metabolism, β-oxidation, aldehyde detoxification, and ABC and MFS transport systems, suggesting adaptive responses associated with oxidative-stress management and cellular homeostasis. Rarefaction analyses indicated greater bacterial and viral richness than fungal richness.

Conclusion: The findings indicate multi-kingdom microbial restructuring and functional adaptation under chronic industrial contamination. The proposed Multi-Kingdom Adaptation Workflow (MKAW) provides a systems-level framework for understanding microbial resilience and identifying potential bioindicators and functional targets for industrial soil bioremediation.