Journal of Advances in Microbiology

Seroprevalence and Risk Factors Associated with Hepatitis B Virus Infection at the Ngoyo General Hospital, Republic of the Congo

Sat, 06 Jun 2026 00:00:00 +0000

Hepatitis B remains one of the most widespread chronic viral infections and represents a major public health challenge worldwide. This study aimed to determine the seroprevalence of hepatitis B virus infection and to identify associated risk factors in subjects admitted to the Ngoyo General Hospital in Pointe-Noire. This was a cross-sectional analytical study conducted from January 2022 to December 2025. Sociodemographic data were collected using a questionnaire, while HBsAg detection was performed by ELISA. Statistical analyses were performed using GraphPad Prism software. A total of 1,237 patients were included, with a male predominance of 63.05% versus 36.90% females (sex ratio 1.70 ~2). The mean age was 36.72 ± 10.10 years (18 - 65 years). The most represented age group was 31 to 45 years, at 55.69%. The seroprevalence of HBV infection was 5.50%. Lack of vaccination against HBV was associated with a significant increase in the risk of infection (p = 0.033), as were a history of blood transfusion (p = 0.037) and multiple sexual partners (p = 0.038). After adjustment, a history of tattooing or scarification (p < 0.001) and drug use (p < 0.001) were independently associated with a lower probability of HBV infection. This study demonstrated the existence of risk factors related to the hepatitis B virus within the hospital population and contributes to strengthening awareness, regular clinical follow-up, and long-term management of patients infected with HBV.

Freeze-dried Starter Production and Viability Measurements with Bacillus and Lactic Acid Bacteria

Fri, 12 Jun 2026 00:00:00 +0000

Freeze-drying, or lyophilization, is a preservation technique that removes water content from microbial cultures under low temperature and vacuum conditions. This process not only maintains the viability of bacillus and LAB but also retains their functional properties, making them suitable for various culinary applications. The aim of this study is produce freeze-dried starter cultures and assess their viability. Two microbial strains, previously, Bacillus proteolyticus and Lactobacillus plantarum was isoled from african locus bean were used. To the mixture of these strains, protective agents and carrier has been added at a ratio of 1 : 1. The mixtures were freeze-dried. The lyophilized starters were stored at -20 °C, 4 °C, and at room temperature (29 ± 0.67 °C). The viability rate was determined every 14 days for 3 months. The results show that cassava powder and starch allow for better viability of microbial strains. The best storage time is -20°C. For good viability of microbial strains during the production of freeze-dried starters, starch must be used as a protective agent, cassava powder as a carrier and everything must be kept at -20 °C. The viability of strains generally decreases over time, even under optimal conditions. Cumulative damage to cellular structures and nucleic acids would lead to cell death. Exposure to oxygen would cause oxidative stress, particularly for anaerobic microorganisms such as lactic acid bacteria. During the storage of the lyophilised products at −20°C, 4°C, and room temperature, the starch–cassava powder formulation used as a protective agent and carrier support demonstrated the highest viability rate for the multiple starter cultures. This finding suggests that the starch–cassava powder matrix was more effective in preserving microbial cell viability across different storage conditions, thereby enhancing the stability and survivability of the starter cultures during storage.

Sensory Evaluation of Rabri Prepared from Cow Milk as Affected by Various Sugar Levels and Storage Periods

Mon, 22 Jun 2026 00:00:00 +0000

Rabri is a traditional heat-desiccated dairy product prepared by concentrating milk and incorporating successive layers of clotted cream formed during slow heating. The present investigation was conducted in the Department of Animal Husbandry and Dairying (Dairy Technology), C.S.A. University of Agriculture and Technology, Kanpur, to evaluate the influence of milk fat level, sugar level and refrigerated storage period on the sensory quality of rabri prepared from cow milk. Milk was standardised to two fat levels, 4.0% (A1) and 4.5% (A2), and rabri was prepared with four sugar levels, namely 2% (B1), 4% (B2), 6% (B3) and 8% (B4). The samples were packed in plastic cups and stored at 5 ± 1°C for 0, 5, 10, 15, 20 and 25 days. Sensory attributes, including flavour, body and texture, colour and appearance, sweetness and overall acceptability, were evaluated by a five-member panel using a 9-point hedonic scale. The experiment included 48 treatment combinations with three replications under a factorial completely randomised design, and the data were analysed using analysis of variance. Rabri prepared from milk containing 4.5% fat recorded higher mean scores than that prepared from milk containing 4.0% fat for flavour (7.513), body and texture (7.386), colour and appearance (7.409), sweetness (7.379) and overall acceptability (7.412). Among the sugar treatments, 2% sugar gave the highest mean scores for all sensory attributes. Fresh rabri obtained the highest acceptability, while all sensory scores declined progressively during storage, with the lowest overall acceptability score observed on day 25 (5.704). Overall, rabri prepared with 4.5% fat and 2% sugar showed the most acceptable sensory quality under refrigerated storage conditions.

Hantavirus at the Human–rodent Interface: A Global Review and Meta-analysis of Occupational Exposure

Thu, 11 Jun 2026 00:00:00 +0000

Hantaviruses are zoonotic negative-sense RNA viruses transmitted to humans principally through inhalation of aerosolised excreta from persistently infected rodent reservoir hosts. They cause two major clinical syndromes: haemorrhagic fever with renal syndrome (HFRS), predominant across Eurasia, and hantavirus pulmonary syndrome (HPS) or hantavirus cardiopulmonary syndrome (HCPS), occurring predominantly in the Americas. Together, these syndromes account for an estimated 150,000–200,000 clinical cases annually, with case fatality rates ranging from less than 0.1% in mild Puumala virus nephropathia epidemica to greater than 50% in Araraquara virus-associated HCPS. Occupational cohorts—including agricultural and forestry workers, military personnel, and laboratory researchers—face disproportionately elevated exposure risks at the human–rodent interface, yet this occupational burden remains inadequately characterised in the global health literature. This critical narrative review, augmented by meta-analytic synthesis of published seroprevalence data, assembles and evaluates the global evidence for hantavirus epidemiology, ecology, transmission, clinical disease, diagnostics, and prevention, with particular focus on occupational risk. Structured searches of multiple biomedical and specialised databases identified peer-reviewed studies published between 2000 and 2024. Pooled seroprevalence estimates across occupational cohorts consistently exceed background population rates by 2- to 10-fold, with the highest estimates observed in Chinese and Korean farmers (8–26%) and European forestry workers (5–15%). Occupational risk is modulated by rodent population dynamics, climate variability, land-use change, and individual behavioural factors. The review critically appraises current diagnostic tools, surveillance frameworks, therapeutic options, and vaccine development, identifies key gaps in occupational health policy, and argues for a strengthened One Health approach to hantavirus surveillance and prevention, particularly in low- and middle-income countries where the burden is least well characterised.

Extraction Methods for Plant-derived Antimicrobial Phytochemicals and Their Testing Techniques: A Scoping Review

Fri, 12 Jun 2026 00:00:00 +0000

Plant-derived antimicrobials have demonstrated significant potential for therapeutic applications. However, the extraction of antimicrobial compounds from plants is a complex process involving various methods used to isolate and concentrate bioactive molecules responsible for antibacterial, antifungal, and antiviral activities. This review study aims to thoroughly investigate and evaluate the process of extracting antibacterial substances from plants and the many techniques used to assess their antimicrobial effectiveness in recent studies. This scoping review study was carried out in accordance with the PRISMA-ScR 2018 checklist guidelines. Google Scholar, PubMed, and PubMed Central were the electronic databases utilised in the search for articles. 84 articles published from January 2020 to December 2024 were included for the review. Among the conventional extraction methods, crude solvent extraction was the most prevalent extraction method, followed by maceration, Soxhlet extraction 11 (11.7%), distillation, and the conventional shaking process. The most predominantly applied advanced extraction techniques were ultrasonification-assisted extraction, followed by the microwave-assisted extraction technique. Assessing the most applied antimicrobial assay technique, Agar well diffusion was the most employed technique, followed by disc diffusion, Broth dilution, Microwell dilution, and time-kill assay. The bacterial and fungal isolates used for testing across the study are of pathological importance and readily available, including bacterial species such as Staphylococcus sp., Escherichia sp., Salmonella sp., Klebsiella sp., and Pseudomonas sp., as well as Shigella sp. Fungal isolates used across the studies included Candida sp., Aspergillus sp., Penicillium, Fusarium, and Rhizopus, among others. While conventional methods are mainly utilised for small-scale research purposes due to their less cost-intensive nature, advanced methods of extraction are gradually taking over the scene; it is important to ascertain in further studies to what extent the method of extraction affects the efficacy of the antimicrobial substances.