South Asian Journal of Research in Microbiology

Bacteriological Quality of Domestic Water Sources and Household Sanitation Practices in a Tin Mining–impacted Settlement in Jos, Nigeria

Sat, 11 Apr 2026 00:00:00 +0000

Water, sanitation, and hygiene (WASH) remain critical public health challenges in low-income and environmentally degraded communities. This study assessed household sanitation and hygiene practices alongside the bacteriological quality of domestic water sources in Twanchik community, a tin mining–impacted settlement in Jos, Nigeria. A cross-sectional survey of 100 randomly selected households collected data on WASH using a structured questionnaire, while 50 water samples were analyzed for total heterotrophic bacterial counts (THBC) and fecal coliform counts (FCC) using membrane filtration, with bacteria species identified using conventional microbiological procedures. Results revealed suboptimal WASH conditions, including toilet sharing (45%), open defecation (21%), indiscriminate waste disposal into streams (68%) and open areas (26%), limited handwashing facilities (16%), and handwashing frequency (52%). Of the households, 63% lived in private residences and 37% in shared compounds, with 53% comprising 1–5 occupants. Livelihoods of residents were mainly trading (34%) and 46% had attained secondary education. Water sources varied seasonally: protected wells dominated the dry season (65%), while rainwater harvesting (42%) and wells (52%) were primary in the rainy season; 58% of households did not treat water. Residents reported dissatisfaction with water availability (60%) and access (68%), and noted seasonal changes in taste (72%), color (45%), and odor (25%). Bacteriological quality of water sources revealed elevated THBC (1.40 × 10² ± 7.39 × 10¹ CFU/100 mL (control) to 9.75 × 10² ± 4.50 × 10¹ CFU/100 mL (spring water) and FCC from 1.80 × 10¹ ± 5.83 × 10⁰ to 1.95 × 10² ± 3.50 × 10¹ CFU/100 mL, exceeding WHO limits. Escherichia coli (36.5%) predominated, followed by Klebsiella spp. (18.8%) and Enterobacter spp. (14.1%). These findings indicate substantial deficiencies in WASH and bacteriological quality of water sources, driven by both behavioral practices and environmental constraints. Therefore, improved WASH practices and environmental remediation are integrated interventions required to reduce risk of waterborne disease infections in the mining-impacted settlement.

Valorization of Wheat Bran for PHBV Copolymer Production by Bacillus subtilis SMI3: Optimization, Structural Characterization, and Biodegradability

Thu, 30 Apr 2026 00:00:00 +0000

Background: Selecting an appropriate microbial host is as critical as choosing a suitable feedstock. Gram-negative bacteria such as Cupriavidus necator are known for their high polyhydroxybutyrate (PHB) yields; however, the presence of lipopolysaccharide endotoxins complicates downstream purification, particularly for applications in food and medicine.

Aims: The present study evaluates the potential of wheat bran, an abundant agricultural by‑product, as a low‑cost substrate for polyhydroxyalkanoate (PHA) production using a newly isolated Bacillus subtilis strain SMI3, and to optimize fermentation conditions, characterize the polymer, and assess its biodegradability.

Study Design: Laboratory‑scale experimental study for bioprocess optimization and polymer characterization.

Place and Duration of Study: Department of Microbiology, Faculty of Life Sciences, Bayero University, Kano, Nigeria; between March 2024 and February 2025.

Methodology: Bacillus subtilis SMI3 was isolated from fadama soil, screened for intracellular PHA accumulation using Sudan Black B and Nile Blue A, and identified by 16S rRNA gene sequencing. Wheat bran was hydrolyzed by dilute acid (5% H₂SO₄, 121°C, 30 min) to obtain fermentable sugars. One‑factor‑at‑a‑time (OFAT) screening evaluated incubation time (24–120 h), pH (6.5–8.5), temperature (25–45°C), substrate concentration (1–5% w/v), and inoculum size (0.5–4 McFarland). Response surface methodology (RSM) with a four‑factor central composite design (CCD) was then applied. The polymer was extracted and characterized by Fourier transform infrared (FTIR) spectroscopy and gas chromatography–mass spectrometry (GC‑MS). Biodegradability was tested by soil burial over 60 days.

Results: OFAT identified baseline conditions: 72 h, pH 7.0, 35°C, 3 g/L wheat bran, and 3.0 McFarland inoculum. The RSM model was highly significant (R² = 0.9706, p < 0.0001), predicting a maximum yield of 660.00 mg/L, which was experimentally validated. Substrate concentration and inoculum size showed the strongest interactive effect (p = 0.0037). FTIR spectroscopy confirmed the PHA ester carbonyl peak at 1737 cm⁻¹, characteristic of the polyhydroxyalkanoate backbone. GC‑MS revealed a PHBV copolymer containing 28.18% 3‑hydroxybutyrate and 19.66% 3‑hydroxyvalerate – produced without adding any precursor. Soil burial caused 72.5% weight loss after 60 days.

Conclusion: Wheat bran hydrolysate is an effective, low‑cost feedstock for PHBV production by Bacillus subtilis SMI3. The high yield, novel precursor‑free 3HV incorporation, and rapid biodegradability make this process a promising sustainable route for bioplastics within a circular bioeconomy.

Molecular Characterization and Biotechnological Potential of Thermostable Alkaline Lipase-Producing Bacillus Subtilis RSMLLP01 Isolated from Lonar Crater Lake

Sonali Shrikant Patil, Sanchit Rajendra Patil — Fri, 29 May 2026 00:00:00 +0000

Lonar Crater Lake represents a unique haloalkaline ecosystem containing extremophilic microorganisms with significant industrial relevance. The present study aimed to isolate, identify, and characterize alkaline thermostable lipase-producing bacteria from Lonar Lake and evaluate their potential biotechnological applications. Water and sediment samples were subjected to alkaline enrichment and selective screening using olive oil agar medium. Four bacterial isolates were obtained, among which RSMLLP01 showed maximum lipase activity with a hydrolysis zone diameter of 28.4 ± 1.2 mm. Morphological and biochemical analyses identified the isolate as a Gram-positive rod-shaped bacterium with thermotolerant properties. Molecular identification through 16S rRNA sequencing revealed ≥99% similarity with Bacillus subtilis. Partial purification of lipase by ammonium sulfate precipitation demonstrated progressive hydrolytic activity with zone diameters increasing from 8.2 ± 0.4 mm to 24.5 ± 1.1 mm after incubation. UV-visible spectroscopic analysis showed a characteristic absorbance peak at 210 nm confirming the proteinaceous nature of the enzyme preparation. The findings indicate that Bacillus subtilis RSMLLP01 may serve as a promising source of alkaline thermostable lipase with potential applications in detergents, biodiesel production, leather processing, and wastewater treatment. However, further studies involving enzyme kinetics and process optimization are required.

Impact of Haemophilus influenzae Type B Vaccination on Nasal Carriage of Haemophilus influenzae in Children under Five (5) Years of Age in Obio-Akpor LGA, Nigeria

O. N. Abraham, O. A. Ollor, E. G. Nwokah — Thu, 04 Jun 2026 00:00:00 +0000

Background: Haemophilus influenzae type b (Hib) remains an important paediatric pathogen, and Hib-containing vaccines have substantially reduced invasive Hib disease; however, the effect on nasopharyngeal carriage and concurrent antimicrobial resistance patterns remains relevant for ongoing surveillance in Nigeria, where the pentavalent (Hib-containing) vaccine was introduced into routine immunisation in 2012.

Aim: This study assessed the impact of Hib vaccination on nasal carriage of Haemophilus influenzae among children aged five (5) years or less in Obio-Akpor Local Government Area, Nigeria, and described the antimicrobial susceptibility patterns of nasal bacterial isolates, with molecular evaluation of selected samples.

Methodology: A cross-sectional study was conducted among 198 children. Nasal swabs were processed using conventional culture and biochemical identification methods, antimicrobial susceptibility testing was performed using the Kirby–Bauer disc diffusion method in line with CLSI 2021 guideline, and molecular analysis (PCR) was conducted on 30 nasal samples. Data were analysed using GraphPad Prism 9, with statistical significance set at p < 0.05.

Results: Culture yielded no H. influenzae isolates; instead, Staphylococcus aureus (44.4%) predominated, followed by Corynebacterium species (26.3%), Staphylococcus epidermidis (7.1%), and alpha-haemolytic Streptococcus (6.1%). PCR detected H. influenzae DNA in 7 (23.3%) of 30 samples despite negative cultures. Antimicrobial susceptibility testing showed widespread multidrug resistance across nasal isolates, with Augmentin resistance of 2 (100.0%), 19 (100.0%), 55 (100.0%), and 9 (100.0%) among alpha-haemolytic Streptococcus (N = 2), Corynebacterium spp. (N = 19), S. aureus (N = 55), and S. epidermidis (N = 9), respectively, and similarly high resistance to multiple cephalosporins and other agents; cefoxitin resistance was particularly high in S. aureus (50 (90.9%)). In contrast, meropenem resistance was 0 (0.0%) across all isolates, while levofloxacin resistance was variable, including 30 (54.5%) in S. aureus and 1 (11.1%) in S. epidermidis.

Conclusion: H. influenzae carriage may persist at levels not detectable by culture in this setting, supporting the integration of molecular methods into carriage surveillance, while the observed resistance patterns among common nasal isolates highlight the need for strengthened antimicrobial stewardship and continued monitoring of community antimicrobial resistance.