Microbiology Research Journal International

Exploring Marine Microorganisms for Antibacterial Activity against Pathogenic Bacteria: A Susceptibility-Based Approach

Kennedy D. Mwambete — 2026-01-27

Aim: To isolate and identify marine microorganisms, assess their antibiotic sensitivity patterns against commonly used antibiotics, and evaluate their potential antibacterial activity against pathogenic Staphylococcus aureus and Escherichia coli.

Study Design: This study investigated the diversity, antimicrobial resistance (AMR), and antibacterial potential of marine microorganisms isolated from Coco Beach, Dar es Salaam, Tanzania. Water samples were randomly collected from three different sites along the beach at depths of 0.5–1.0 meters using pre-sterilized bottles. Samples were transported in a cool box to the Pharmaceutical Microbiology Laboratory at Muhimbili University of Health and Allied Sciences for analysis.

Duration of Study: The study was conducted between February 2025 and June 2025.

Methodology: Conventional microbiological methods were used for the isolation and identification of microorganisms. Antibiotic sensitivity testing was performed using the Kirby–Bauer disc diffusion method on the Mueller Hinton agar. Discrete marine microbial colonies were sonicated, and the resulting suspensions were screened for antibacterial activity against pathogenic S. aureus and E. coli.

Results: A total of 63 water samples yielded 73 marine microorganisms, categorized into Vibrio cholerae, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus flavus, and Rhizopus species. V. cholerae was the predominant organism, accounting for 56 of the 73 isolates. Antibiotic resistance levels ranged from 30% to 100%. All fungal isolates were resistant to fluconazole, while Rhizopus species also showed resistance to amphotericin B. Notably, seven microbial suspensions (9.6%) demonstrated antibacterial activity against pathogenic S. aureus and E. coli, with most activity observed among V. cholerae isolates.

Conclusion: The marine microorganisms from Coco Beach exhibit high levels of antibiotic resistance but also possess notable antibacterial potential. Further research is recommended to identify bioactive compounds and improve waste and pharmaceutical disposal practices to curb AMR spread and protect marine ecosystems.

Gut microbiota Alterations Associated with 1-kestose Supplementation and Owner-reported Aggression-related Behaviors in Dogs

Tadashi Fujii — 2026-01-28

Aims: To characterize fecal gut microbiota features associated with a history of aggression in dogs and to explore whether supplementation with the prebiotic fructooligosaccharide 1-kestose is associated with alterations in gut microbiota composition and owner-reported aggression-related behaviors.

Study Design: An exploratory, non-randomized field study comparing aggressive and non-aggressive client-owned dogs, followed by a single-arm pre–post supplementation study in aggressive dogs with owner-reported behavioral outcomes.

Place and Duration of Study: The study was conducted in Japan between 2021 and 2023, with a 60-day 1-kestose supplementation period for the intervention group.

Methodology: Fecal samples from aggressive toy poodles (Agg; n = 10) and non-aggressive controls (N-Agg; n = 6) were analyzed using 16S rRNA gene sequencing. Dogs in the Agg group received 1-kestose (400 mg/day) for 60 days. Behavioral outcomes were assessed before and after supplementation using the shortened, owner-reported Canine Behavioral Assessment and Research Questionnaire (C-BARQ). Genome analysis of Blautia caecimuris was conducted to identify glycoside hydrolase family 32 (GH32) enzymes, and a recombinant GH32 enzyme was functionally characterized for fructooligosaccharide hydrolysis.

Results: At baseline, Agg dogs differed in gut microbial β-diversity from N-Agg dogs and showed higher relative abundances of Mediterraneibacter gnavus, the Segatella copri group, and the Phocaeicola vulgatus group. Following 1-kestose supplementation, M. gnavus was lower, the B. caecimuris group was higher, and the β-diversity difference between groups diminished. In parallel, owner-reported aggression-related C-BARQ items—particularly responses to unfamiliar dogs and strangers near the home—were lower after supplementation. The characterized GH32 enzyme from B. caecimuris hydrolyzed 1-kestose and nystose.

Conclusion: These findings indicate that 1-kestose supplementation is associated with concurrent alterations in the canine gut microbiota and owner-reported aggression-related behavioral scores. While causality cannot be established, the results support further investigation of microbiota–behavior associations using larger, well-controlled study designs incorporating objective physiological and microbial measurements.

A Hospital-based Study on the Detection of Fluconazole-resistant Candida albicans from Women with Vulvovaginal Candidiasis in Port Harcourt

Giami, Lynda Kadi — 2026-01-28

Fluconazole resistance in Candida albicans represents a significant global public health challenge. This study aimed to assess the susceptibility of C. albicans isolates from women with vulvovaginal candidiasis in Port Harcourt to fluconazole. Standard microbiological techniques were employed for the isolation and identification of C. albicans, including culture on Sabouraud dextrose agar (SDA) and microscopic examination using lactophenol cotton blue staining for presumptive identification. Antifungal susceptibility was evaluated using the agar well diffusion method. Of the twenty-five (25) samples analyzed, fifteen (15) yielded positive C. albicans isolates. These isolates were exposed to fluconazole at varying concentrations: 200 mg/mL (100%), 100 mg/mL (50%), 50 mg/mL (25%), and 25 mg/mL (12.5%). The results demonstrated that 60% of the isolates were fully susceptible to fluconazole, whereas 40% exhibited complete resistance. These findings underscore the importance of avoiding unnecessary or inappropriate fluconazole prescriptions, and highlight that long-term therapy should be guided by laboratory confirmation of susceptibility.

Multidrug-Resistant Aeromonas hydrophila in Retail Fish Markets: Prevalence, Survival and Public Health Implications

P. Siva Sankar — 2026-02-03

Aeromonas hydrophila is a widespread opportunistic pathogen commonly associated with aquatic environments and is responsible for infections in fish and other aquatic organisms. This study investigated during January to February 2025, the prevalence, survival ability and antibiotic resistance of Aeromonas hydrophila isolated from local fish markets in and around Salem, Tamil Nadu. The bacterium was detected in 33.29% out of 48 fish samples obtained, indicating a significant level of contamination, while 20% of Musca domestica samples (1/5), also tested positive, suggesting their role as potential mechanical vectors. Antibiotic susceptibility profiling revealed that the potential isolate (CS1) showed resistant to ampicillin, amoxyclav, cephalexin, cefazolin, methicillin, oxacillin and vancomycin, indicating the presence of multidrug resistant strains. Survival studies showed that Aeromonas hydrophila could adhere to and persist on commonly used market surfaces such as stainless steel, wood, iron and thermocol. It also exhibited tolerance to a wide range of pH and temperature conditions. Experiments with common Indian cooking ingredients demonstrated varying inhibitory effects and several disinfectants and antiseptics were effective against the isolates. These findings highlight Aeromonas hydrophila contamination may cause public health issues such as gastrointestinal tract infections, septicemia, peritonitis in specifically in immunosuppressive persons. Emphasize the need for improved hygiene and handling practices in fish markets.

Isolation and Biochemical Characterization of Yeast Strains from Fruits

Misbahfathima G — 2026-02-03

The present study focused on the isolation and biochemical characterization of yeast strains from fruits to evaluate their metabolic and functional diversity. Yeasts were isolated from fresh fruit samples such as grape, orange, pineapple, lychee, sugarcane juice, using Yeast Glucose Agar supplemented with chloramphenicol. Five yeast isolates (YS1–YS5) were obtained and highest count of 2.56 log₁₀ CFU/mL in sugarcane juice. Morphological characterization using lactophenol cotton blue staining revealed oval to round yeast cells with budding and occasional ascospores. Biochemical characterization demonstrated considerable variability among the isolates. Sugar fermentation tests showed positive fermentation for YS2, YS3 and YS4. Nitrogen utilization studies indicated that all isolates could utilize ethylamine and tryptophan, while only YS5 was able to utilize DL-lysine. Complementary tests revealed that most isolates tolerated 5–10% NaCl (YS1-YS5) and 1% acetic acid (except YS 1), with several strains showing delayed but measurable growth even at 16% NaCl, indicating strong stress tolerance. Urease activity was not detected in any isolates. Oxidation–fermentation tests showed predominantly oxidative metabolism, Overall, the results highlight significant physiological and metabolic diversity among yeast isolates from food sources, suggesting their potential applicability in fermentation processes and functional food development.

Host Plant Resistance to Important Viruses in Cucurbits- Current Challenges and Advances

Chandrika Ghoshal — 2026-01-27

Cucurbit crops like cucumber, melon, squash, and watermelon are vital vegetables grown globally. Their production is under serious threat by viral diseases caused by a wide array of plant viruses including Cucumber mosaic virus (CMV), Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), and Papaya ringspot virus (PRSV). They cause severe yield losses and reduced fruit quality, forming a significant challenge for sustainable cucurbit production. Host plant resistance (HPR) provides a viable, environmentally friendly, and economically sound approach for controlling viral diseases in cucurbits. The present review presents an overview of the status of host resistance to major cucurbit-infecting viruses, including the origin of natural resistance, the pattern of inheritance, and the progress of breeding strategies. Conventional breeding, marker-assisted selection (MAS), transgenic methodology, and genome editing tools have all played roles in generating virus-resistant varieties. Nonetheless, the speedy development of viral strains, collapse of resistance, and narrow genetic diversity in certain cucurbit crops are still challenges. Combining genomic resources, high-density phenotyping, and bioinformatics is enabling the discovery and deployment of enduring resistance genes. In addition, utilization of wild relatives and landraces as a source of resistance is receiving increased interest. This review highlights the importance of interdisciplinarity to engineer broad-spectrum and lasting resistance. Host plant resistance will be critical for food security and decreasing the dependency on chemical controls in cucurbit production systems.

Advances in Breeding, Nutrition and Culture Practices of Indian Major Carps for Sustainable Aquaculture

G. Ganesh — 2026-01-30

Indian Major Carps Catla catla, Labeo rohita and Cirrhinus mrigala constitute the foundation of freshwater aquaculture in India and significantly contribute to fish production in Telangana. This review synthesizes current knowledge on taxonomy, biology, broodstock management, induced breeding, seed rearing, nutrition, pond preparation and health management to provide an integrated understanding of IMC culture systems. Advances in broodstock nutrition, genetic management and hormone based spawning (Ovaprim, Ovatide, GnRH analogues) have improved seed quality and hatchery reliability. Recent integrated advances in Indian major carp aquaculture include selective breeding of improved carp strains, use of nutritionally balanced low-fishmeal diets supplemented with probiotics and immunostimulants, and adoption of advanced culture systems such as biofloc, RAS, and improved polyculture models. Together, these innovations enhance growth, resource-use efficiency, environmental sustainability, and resilience of carp farming systems. Enhanced nursery and grow-out practices, including optimized fertilization regimes, zooplankton production and species specific stocking densities, support high fry survival and fingerling growth. Nutritional developments particularly balanced pelleted feeds rich in essential amino acids, PUFA, vitamins and minerals have markedly increased growth performance and feed efficiency. Water quality regulation, through liming, aeration and routine monitoring of key parameters (DO, pH, alkalinity, ammonia) ensures optimal pond ecology and fish health. Disease management strategies addressing bacterial, parasitic and fungal infections further strengthen overall system resilience. Collectively these technological and management advancements have substantially elevated productivity, sustainability and economic outcomes in IMC aquaculture. The review underscores the need for continued integration of genetics, nutrition and environmental management to support future intensification and blue economy goals.

New World Arenaviruses: Host Reservoirs, Viral Diversity and Pathogenic Mechanisms

DINIZ PEREIRA LEITE JÚNIOR — 2026-02-04

Introduction: Arenaviridae can cause diseases such as lymphocytic choriomeningitis, Lassa fever, Argentine hemorrhagic fever, Bolivian hemorrhagic fever, and Brazilian hemorrhagic fevers. Their main etiological agents are Sabiá virus, Flexal virus, Amapari virus, Juquitiba virus, lymphocytic choriomeningitis virus, Lassa virus, Junin virus, and Machupo virus.

Objective: Show the degree of infection of New World arenaviruses associated with rodents of the genera Calomys, Necomys, Neotoma, Oryzomys, and Sigmodon, subfamily Sigmodontinae and family Cricetidae, and Old World arenaviruses associated with rodents of the genera Mastomys and Praomys of the subfamily Murinae and family Muridae. The exception is the Tacaribe virus, which was isolated from bats of the genus Artibeus spp.

Methodology: Infected urine from various rodent species and person-to-person transmission are the modes of infection for this disease.

Results: Infections range from asymptomatic in all cases to fatal in some, or even febrile illness with systemic symptoms generally including headache, myalgia, weakness, sore throat, and gastrointestinal symptoms, as well as hemorrhage and late neurological disease. Differential immune responses, destruction of T cells from infected cells in the central nervous system, can be observed, creating disturbances in the hemostatic system and endothelium, resulting in bleeding and shock. Isolation of the virus from blood, cerebrospinal fluid, or tissues, with evaluation of IgG and IgM antibodies, are specific for virus recognition.

Conclusion: LCM occurs throughout the Americas, Europe, and Asia. All result from contact with infected rodent urine, usually through contamination of cuts and scratches on the skin.