With the advancements of science, antibiotics have emerged as an amazing gift to the human and animal healthcare sectors for the treatment of bacterial infections and other diseases. However, the evolution of new bacterial strains, along with excessive use and reckless consumption of antibiotics have led to the unfolding of antibiotic resistances to an excessive level. Multidrug resistance is a potential threat worldwide, and is escalating at an extremely high rate. Information related to drug resistance, and its regulation and control are still very little. To interpret the onset of antibiotic resistances, investigation on molecular analysis of resistance genes, their distribution and mechanisms are urgently required. Fine-tuned research and resistance profile regarding ESKAPE pathogen is also necessary along with other multidrug resistant bacteria. In the present scenario, the interaction of bacterial infections with SARS-CoV-2 is also crucial. Tracking and in-silico analysis of various resistance mechanisms or gene/s are crucial for overcoming the problem, and thus, the maintenance of relevant databases and wise use of antibiotics should be promoted. Creating awareness of this critical situation among individuals at every level is important to strengthen the fight against this fast-growing calamity. The review aimed to provide detailed information on antibiotic resistance, its regulatory molecular mechanisms responsible for the resistance, and other relevant information. In this article, we tried to focus on the correlation between antimicrobial resistance and the COVID-19 pandemic. This study will help in developing new interventions, potential approaches, and strategies to handle the complexity of antibiotic resistance and prevent the incidences of life-threatening infections.

Aeromonas hydrophila isolated from fish (Labeo rohita), pond water, river water, raw meat of chicken and mutton and raw cow milk were characterized through Random Amplified Polymorphic DNA (RAPD) analysis and Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE) of cellular proteins. RAPD-PCR amplification of bacterial DNA was done by using ten random primers (OPA-01 to 10) and found some distinct banding pattern on agarose gel. RAPD profile was studied with each isolate and absolute polymorphism indicating its application as an ideal tool for molecular characterization. Other methods like morphological, serological and biochemical characterization gives contradictory results and total cellular protein profiling does not show any significant polymorphism for identification and discrimination.

The pathogenicity of aeromonads produces due to exotoxins such as cytolytic enterotoxin, hemolysin or aerolysin, lipases and proteases. Rapid detection of A. hydrophila cytolytic enterotoxin (AHCYTONE) gene and their characterization has proven importance so that proper and rapid preventive and control measures could be taken up to reduce mortality and loss in fish culture. The main objective of the present study is to genetic identification of AHCYTONE positive Aeromonas hydrophila. Strains were isolated from fishes from different fish market in West Bengal and water samples from different river and ponds. Initially strains were identified by their phenotypic and biochemical characterization. Due to contradiction of those results, molecular characterization was done by polymerase chain reaction, which is proved a suitable and rapid diagnostic tool for identification and characterization of A. hydrophila. We have also evaluated the potential risk to human health that this finding can represent by determining the presence of the cytolytic enterotoxin gene in such isolates.

East Kolkata Wetlands (EKW) is designated as International Ramsar site and are the hotspot for large-scale wastewater aquaculture practices. However, the continued surveillance of physicochemical properties of water and application of an eco-friendly approach are essential to ensure safe aquaculture practices. In the present study, we assessed the seasonal variation in physicochemical parameters of water across EKW and investigated the role of nitrifying bacteria as probiotics. We statistically analyzed various physicochemical properties of water samples from EKW. Results of the statistical analysis indicated a significant variation in all the physicochemical parameters across the selected water bodies of EKW (p < 0.01). We isolated and enumerated Nitrosomonas sp. and Nitrobacter sp. and assessed their ability to degrade trichloroethylene (TCE). The role of Nitrosomonas and Nitrobacter sp. were further investigated and established through a small-scale experiment. Two microbial isolates, NSW3 and NBW2, displayed superior TCE degradation ability at pH 5, and the application of these strains as probiotics were found to improve the quality of water and survival rate of fishes in the treated experimental tanks. Our findings suggest that the application of the above mixed bacterial cultures in aquaculture could be an effective and environment-friendly approach for safe and productive aquaculture operations.

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