Synthesis of a tetralone derivative of ampicillin to control ampicillin-resistant Staphylococcusaureus.

Due to the rapid emergence of antibiotic resistant new bacterial strains and new infections, there is an urgent need for novel or newly modified and efficient alternatives of treatment. However, conventional antibiotics are still used in therapeutic settings but their efficacy is uncertain due to the rapid evolution of drug resistance. In the present study, we have synthesized a new derivative of conventional antibiotic ampicillin using SN2-type substitution reaction. NMR and mass analysis of the newly synthesized derivative of ampicillin confirmed it as ampicillin-bromo-methoxy-tetralone (ABMT). Importantly, ABMT is revealed to have efficient activity against Staphylococcus aureus (S. aureus) with a MIC value of 32 µg ml-1 while ampicillin was not effective, even at 64 µg ml-1 of concentration. Electron microscopy results confirmed the membrane-specific killing of S. aureus at 1 h of treatment. Additionally, molecular docking analysis revealed a strong binding affinity of ABMT with ß-lactamase via the formation of a closed compact bridge. Our findings, avail a new derivative of ampicillin that could be a potential alternative to fight ampicillin-resistant bacteria possibly by neutralizing the ß-lactamase action.

Biologia Futura: use of biocides during COVID-19-global reshuffling of the microbiota.

Aim The article reviews the current usage of biocides during this lockdown period for sanitizing our living areas due to the pandemic and discusses the pros and cons. Subject COVID-19 spread like wildfire to over 200 countries of the world across all continents. The causative agent, novel coronavirus (SARS-CoV-2) is being counter attacked by a thorough application of disinfectants and sterilants. However, the virus mutated over 30 times during this global pandemic, creating panic and leading to enhanced pathogenicity and consequently to more stringent sanitation measures for controlling it. However, excessive use of different types of biocides for disinfecting surfaces is highly alarming in several cases. Extensive application of biocides affects the microbial flora, leading to an abrupt decrease in the number and diversity of beneficial microbes that may directly affect the functioning of nutrient cycles. Results The increased concentration of biocides in agricultural land via surface water or pond water indirectly affect the soil and water ecosystem, soil aggregation and fertility. This will also lead to the flourishing of resistant strains due to loss of competition from the other species, which fail to persist after prolonged use of biocides. Conclusion It is necessary to realize the environmental impacts of biocides and sterilants. It is the right time to stop their entry into the agricultural ecosystem by following adequate management strategies and complete neutralization.

Trends of mutation accumulation across global SARS-CoV-2 genomes: Implications for the evolution of the novel coronavirus.

To understand SARS-CoV-2 microevolution, this study explored the genome-wide frequency, gene-wise distribution, and molecular nature of all point-mutations detected across its 71,703 RNA-genomes deposited in GISAID till 21 August 2020. Globally, nsp1/nsp2 and orf7a/orf3a were the most mutation-ridden non-structural and structural genes respectively. Phylogeny of 4618 spatiotemporally-representative genomes revealed that entities belonging to the early lineages are mostly spread over Asian countries, including India, whereas the recently-derived lineages are more globally distributed. Of the total 20,163 instances of polymorphism detected across global genomes, 12,594 and 7569 involved transitions and transversions, predominated by cytidine-to-uridine and guanosine-to-uridine conversions, respectively. Positive selection of nonsynonymous mutations (dN/dS >1) in most of the structural, but not the non-structural, genes indicated that SARS-CoV-2 has already harmonized its replication/transcription machineries with the host metabolism, while it is still redefining virulence/transmissibility strategies at the molecular level. Mechanistic bases and evolutionary/pathogenicity-related implications are discussed for the predominant mutation-types.