Antimicrobial Resistance in the Environment

Phytomolecules as potential candidates to intervene the function of E. coli sodium-proton antiporters; Ec-NhaA

Sodium-Proton antiporter, NhaA is a ubiquitous protein found in cytoplasmic membranes of all the prokaryotic and eukaryotic systems. These antiporters have been widely studied in E. coli and their homologs, observed in humans, are found to be crucial for various pathophysiological conditions, such as hypertension, cardiac diseases, blood pressure fluctuation etc. NhaA is responsible for the virulent properties of many pathogens like Vibrio cholerae, Yersinia pestis etc. In the present work, we have exploited in silico approaches to find lead phytomolecules that have the efficacy to interfere with the activities of sodium-proton antiporters in E. coli. A database of the plant-based natural bioactive compounds was used to screen 350 phytochemicals from various plant sources as potential ligands for the Ec-NhaA protein (PDB ID: 4ATV). Further interactions between Ec-NhaA and ligands were analyzed by AutoDock Vina and proposed 46 ligands with a significant affinity for NhaA where the binding energy range from -7.5 to -9.3 kcal/mol. Physiochemical characterization suggested 26 ligands with non-BBB permeability, good GI absorption and solubility. As a final step, MD simulation for more than 100 ns duration suggested Luteolin, Apigenin and Rhamnocitrin with the best affinity and showing potential stable interaction with the target protein. This study proposed the potential compounds of natural origin as an interfering agent against sodium-proton transport activity that may lead to affect the survival of various pathogenic bacteria.Communicated by Ramaswamy H. Sarma.

Spatiotemporal distribution of antimicrobial resistant organisms in different water environments in urban and rural settings of Bangladesh

The spatial distribution of clinically important antibiotic resistant bacteria (ARB) and associated genes is important to identify the environmental distribution of contamination and 'hotspots' of antimicrobial resistance (AMR). We conducted an integrated survey of AMR in drinking water, wastewater and surface water (rivers and ponds) in three settings in Bangladesh: rural households, rural poultry farms, and urban food markets. Spatial mapping was conducted via geographic information system (GIS) using ArcGIS software. Samples (n = 397) were analyzed for the presence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec), carbapenem-resistant E. coli (CR-Ec) and resistance genes (bla_CTX-M-1,bla_NDM-1). In rural households, 5% of drinking water supply samples tested positive for ESBL-Ec, and a high proportion of wastewater, pond and river water samples were positive for ESBL-Ec (90%, 76%, and 85%, respectively). In poultry farms, 10% of drinking water samples tested positive for ESBL-Ec compared to a high prevalence in wastewater, pond and river water (90%, 68%, and 85%, respectively). CR-Ec prevalence in household wastewater and pond water was relatively low (8% and 5%, respectively) compared to river water (33%). In urban areas, 38% of drinking water samples and 98% of wastewater samples from food markets tested positive for ESBL-Ec while 30% of wastewater samples tested positive for CR-Ec. Wastewaters had the highest concentrations of ESBL-Ec, CR-Ec, bla_CTXM-1 and bla_NDM-1 and these were significantly higher in urban compared to rural samples (p < 0.05). ESBL-Ec is ubiquitous in drinking water, wastewater and surface water bodies in both rural and urban areas of Bangladesh. CR-Ec is less widespread but found at a high prevalence in wastewater discharged from urban food markets and in rural river samples. Surveillance and monitoring of antibiotic resistant organisms and genes in waterbodies is an important first step in addressing environmental dimensions of AMR.

Occurrence of Antibiotic Resistance in the Mediterranean Sea

Seawater could be considered a reservoir of antibiotic-resistant bacteria and antibiotic resistance genes. In this communication, we evaluated the presence of bacterial strains in seawater collected from different coasts of Sicily by combining microbiological and molecular methods. Specifically, we isolated viable bacteria that were tested for their antibiotic resistance profile and detected both antibiotic and heavy metal resistance genes. Both antibiotic-resistant Gram-negative bacteria, Vibrio and Aeromonas, and specific antibiotic resistance genes were found in the seawater samples. Alarming levels of resistance were determined towards cefazolin, streptomycin, amoxicillin/clavulanic acid, ceftriaxone, and sulfamethoxazole/trimethoprim, and mainly genes conferring resistance to β-lactamic and sulfonamide antibiotics were detected. This survey, on the one hand, presents a picture of the actual situation, showing the pollution status of the Tyrrhenian coast of Sicily, and, on the other hand, can be considered as a baseline to be used as a reference time for future analysis.

Unveiling the Potential Role of Nanozymes in Combating the COVID-19 Outbreak

The current coronavirus disease 2019 (COVID-19) outbreak is considered as one of the biggest public health challenges and medical emergencies of the century. A global health emergency demands an urgent development of rapid diagnostic tools and advanced therapeutics for the mitigation of COVID-19. To cope with the current crisis, nanotechnology offers a number of approaches based on abundance and versatile functioning. Despite major developments in early diagnostics and control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is still a need to find effective nanomaterials with low cost, high stability and easy use. Nanozymes are nanomaterials with innate enzyme-like characteristics and exhibit great potential for various biomedical applications such as disease diagnosis and anti-viral agents. Overall the potential and contribution of nanozymes in the fight against SARS-CoV-2 infection i.e., rapid detection, inhibition of the virus at various stages, and effective vaccine development strategies, is not fully explored. This paper discusses the utility and potential of nanozymes from the perspective of COVID-19. Moreover, future research directions and potential applications of nanozymes are highlighted to overcome the challenges related to early diagnosis and therapeutics development for the SARS-CoV-2. We anticipate the current perspective will play an effective role in the existing response to the COVID-19 crisis.

Detection of Carbapenem-Resistance Genes in Klebsiella Species Recovered from Selected Environmental Niches in the Eastern Cape Province, South Africa

Carbapenemase-producing Enterobacteriaceae (CPE) have been heavily linked to hospital acquired infections (HAI) thereby leading to futility of antibiotics in treating infections and this have complicated public health problems. There is little knowledge about carbapenemase-producing Klebsiella spp. (CPK) in South Africa. This study aimed at determining the occurrence of CPK in different samples collected from selected environmental niches (hospitals, wastewater treatment plants, rivers, farms) in three district municipalities located in the Eastern Cape Province, South Africa. Molecular identification and characterization of the presumptive isolates were determined using polymerase chain reaction (PCR) and isolates that exhibited phenotypic carbapenem resistance were further screened for the possibility of harbouring antimicrobial resistance genes. One hundred (43%) of the 234 confirmed Klebsiella spp. isolates harboured carbapenem-resistance genes; 10 isolates harboured blaOXA-48-like; 17 harboured blaKPC; and 73 isolates harboured blaNDM-1. The emergence of blaKPC, blaOXA-48-like, and blaNDM-1 carbapenem-resistance genes in Klebsiella species associated with environmental sources is of great concern to public health.