Applied Microbiology: Theory ＆ Technology

Bacteriological Quality of Pond Water Used in Aquaculture in Enugu State, Nigeria

2024-12-05T08:51:13+08:00

The bacteriological quality of fish pond water is an essential consideration in fish cultivation. Poor quality water can lead to outbreaks of bacterial infections in fish. Fish pond water can be contaminated due to improper location, inadequate sewage treatment, effluents, and agrochemicals from nearby industries and farms, as well as exposure to poor sanitation systems from various households leaching into water sources used in fish farms. Water from a total of ten fish pond was evaluated for the presence of bacterial pathogens. Microbial isolation, identification, and antibiogram screening were performed using standard methods. The result indicates that microbial bacteria were found in all fish ponds water that was assessed. Fecal coliform counts (cfu/ml) show that pond water was contaminated with pathogens due to pollution from fecal sources. The bacterial isolates were identified and the frequency was recorded as Vibrio spp. (26.2%), Klebsiella spp. (21.4%), Salmonella spp. (9.5%); Staphylococcus spp. (16.7%); Escherichia coli (9.5%) and Shigella spp. (16.7%). The isolates were examined for susceptibility against twelve antibiotics namely; Ciproflox, Norfloxacin, Gentamycin, Amoxil, Streptomycin, Rifampicin, Erythromycin, Chloramphenicol, Amicloxz, Levofloxacin, Augumentin and Cotrimoxazole. The result showed the bacterial isolates had varying levels of susceptibility, and were resistant to the antimicrobials. Therefore, it is imperative to assess pond water used in aquaculture systems periodically to ensure the production of quality and safe fish for human consumption.

A Quorum-Sensing-Based Genetic Circuit for Bioengineered Bacterial Treatment of Bovine Mastitis

2025-01-07T08:48:39+08:00

Bovine mastitis is a significant challenge for the dairy industry, affecting milk production, quality, and cow health. Traditional antibiotic-based treatments raise concerns about resistance and residual antibiotics in dairy products, creating an urgent need for sustainable alternatives. This study explores a genetically modified organism (GMO)-based, antibiotic-free treatment targeting Staphylococcus aureus, a primary mastitis-causing pathogen. This study proposes using the bioengineered defensin Nisin PV, which has enhanced stability and reduced susceptibility to proteolytic degradation compared to Nisin A. This makes it a more effective, pathogen-specific alternative to broad spectrum antibiotics, reducing off-target effects and supporting responsible antimicrobial stewardship. To disrupt biofilm formation, this study utilizes deoxyribonuclease I (DNase I), an enzyme that degrades extracellular deoxyribonucleic acid (DNA), a key structural biofilm component. This genetically modified bacteria detects S. aureus through its agr quorum sensing system and responds by producing Nisin PV and DNase I. Experimental results confirm DNase I’s efficacy asgainst biofilm formation and validate this quorum sensing-based pathogen detection mechanism. Molecular dynamics simulations further suggest that Nisin PV resists cleavage by bacterial strains resistant to Nisin A. A regulated lysis mechanism is proposed to ensure controlled therapeutic release. This study highlights the potential of bioengineered defensins as an effective, sustainable alternative to antibiotics, offering a promising strategy to reduce mastitis incidence and economic losses in the dairy industry.

The Incidence of Non-Tuberculous Mycobacteria (NTM) in TB Culture Samples in a South Indian Sub-Population: A Laboratory-Based Study

2025-02-12T09:27:58+08:00

Non-Tuberculous Mycobacteria (NTM) are now considered globally evolved emerging pathogens, causing infections ranging from self-limiting asymptomatic to life-threatening infections affecting multiple major organs. Numerous directives have been implemented to treat NTM infections, but owing to their innate resistance, complexity, and resemblance to Mycobacterium Tuberculosis (MTB), the diagnosis and treatments have a high failure rate. The study was designed to estimate the incidence of MTB and NTM infection and identify the occurrence of NTM. In our study, a retrospective analysis of 6 years (January 2017 to December 2022) was done using laboratory data. All the samples received for Acid-Fast Bacilli (AFB) culture were included. Standard Auramine O and Ziehl Neelsen (ZN) staining, Lowenstein Jensen (LJ) medium, and an automated BacT Alert Mycobacteria Indicator Tube (MGIT) for inoculation. Differentiation between MTB and NTM was done using a TB antigen MPT64 rapid test kit. Anonymized data resulting from the generalization method was used for statistical analysis. Our study found that the incidence of NTM was 19.8% among the AFB-positive samples. The infection was found to be more common in males (60.6%) than in females (39.3%). The maximum number of samples received was sputum and BAL, indicating that the pulmonary infection was more than extra-pulmonary. The outcome is consistent with reports of pulmonary infections dominating worldwide. Our year-wise report shows that the cases of both MTB and NTM were found to be on the rising trend. Despite the low cases, it was noted that the number increased over time.

Prevalence, Challenges in Diagnosis and Treatment of Non-Tuberculous Mycobacteria

2025-01-26T10:11:34+08:00

Mycobacteria that cause tuberculosis and Non-Tuberculous Mycobacteria (NTM) are the two groups into which mycobacteria are divided. Almost all the NTM are ubiquitous in soil, water, air, etc. During recent years, studies have suggested that they are now considered globally evolved emerging pathogens. The NTM infection can cause self limiting asymptomatic infections to life-threatening diseases, affecting multiple major organs. Several guidelines have been introduced for the treatment of pulmonary and extra-pulmonary NTM infections. Owing to its innate resistance, complexity, and resemblance of the organism to Mycobacterium Tuberculosis (MTB), the diagnosis and treatments have a high failure rate. Moreover, most healthcare workers lack knowledge of NTM infection, as the clinical symptoms and the microscopic morphology resemble MTB. This could lead to NTM becoming resistant to various antibiotics, and the treatment could become challenging in the future. This review article provides details on the prevalence of Tuberculosis (TB) and NTM in India and globally, information on the vulnerable population, complications caused, and means of diagnosis, treatment, and challenges associated with the diagnosis and treatment of NTM are discussed in detail. Additionally, information on various health complications associated with NTM and the challenges of NTM diagnosis is provided in detail. This article also throws light on co-infections associated with TB and NTM disease patterns that may lead to complications, along with treatment options for NTM are discussed in detail.

Understanding of Research Milestones Embedded Within the History of Plant Viruses Especially Tobacco Mosaic Virus

2024-12-19T14:13:11+08:00

Since the discovery of plant viruses, their profound impact on plant sciences and human society has driven extensive research efforts to understand their nature and develop management strategies. This review examines the evolution of plant virus research across six distinct phases, highlighting advancements in biochemical, structural, and molecular characterization. The first phase marked the identification of plant viruses as novel pathogens, introducing them as a unique area of study. The second phase explored the biological aspects, including modes of transmission and the role of vectors in virus spread. The third phase focused on biochemical and biophysical approaches to purify and characterize plant viruses, laying the foundation for structural virology. The fourth phase introduced molecular biology techniques, elucidating viral replication, heredity, and host interactions at a molecular level. In the fifth phase, molecular genetics advanced our understanding of viral genomes, enabling gene mapping, cloning, and silencing approaches to study gene function and pathogenicity. Finally, the sixth phase emphasized modern diagnostic and management strategies, including advanced detection methods, genetic resistance, and integrated approaches for virus control. Together, these phases represent a comprehensive trajectory of plant virology research, underscoring its relevance to global agriculture, food security, and sustainable crop protection strategies. This review not only provides a historical perspective but also highlights the importance of continued innovation in combating plant viruses and mitigating their impact on crop health and productivity.