Shivranjani Chandrashekhar Moharir

The spillover of pathogenic organisms across the livestock-environmental interface is a major OneHealth concern. To investigate the co-occurrence, antimicrobial resistance profiles, and genomic characteristics of ESBL-E. coli in healthy migratory sheep flocks and associated farm environments, a cross-sectional study was conducted in South Karnataka, India. 9124 animals from 60 farms were included in the study, and 701 samples from sheep and environmental were analysed, during 2023-2025. The occurrence of ESBL-E. coli was comparable in sheep and environmental samples, and exhibited high multidrug resistance patterns. Whole-genome-sequencing and comparative genomic analysis of ESBL-E. coli isolates revealed substantial diversity in antimicrobial resistance genes including resistance-nodulation-cell division family efflux pumps, alterations in β-lactam target proteins such as penicillin-binding proteins, and a wide range of β-lactamase genes, including CTX-M, TEM, DHA, AmpC, and SHV variants. Several plasmid replicon types were detected in both sheep and environmental isolates, suggesting potential plasmid-mediated horizontal gene transfer at the livestock-environment interface. Notably, phenotypic resistance to imipenem was detected in 16.6% of sheep isolates, and stx genes were identified in 19% of isolates, raising additional public health concerns. Overall, the detection of multidrug-resistant ESBL-E. coli in migratory sheep and their surrounding environments, together with shared resistomes, plasmids, and lineages, underscores the role of small non-sedentary ruminants as overlooked nodes in AMR dissemination and highlights the need for targeted OneHealth surveillance strategies.

The detection of diverse pathogens and chemical compounds in community wastewater facilitates the monitoring of public health trends of emerging diseases and health conditions. During the COVID-19 pandemic, detection of viral RNA in wastewater assisted in monitoring the infection rates in different geographies and this drew attention to the method of wastewater-based epidemiology (WBE). In contrast to individual clinical testing, WBE offers an affordable, population-wide overview of the infection status of a community including asymptomatic carriers and those without access to healthcare facilities. To understand the community status of the infections caused by respiratory syncytial virus, SARS-CoV-2 and influenza virus subtypes in the monsoon season in Vijayawada city in the state of Andhra Pradesh in India, we longitudinally analyzed wastewater samples once a week between July-August 2024 from 7 sewage treatment plants in the city. The data obtained from the multiplexed RT-qPCR was used to calculate the viral loads in the wastewater samples at the city level and the proportion of population shedding the virus was estimated. All three viruses RSV A+B, SARS-CoV-2 and Influenza A+B were detected in the wastewater during our sampling period. Amongst the three viruses, the city had the largest load of SARS-CoV-2 RNA in the wastewater followed by RSV A+B and Influenza A+B. The study demonstrates the potential of utilizing wastewater surveillance system coupled to multiplexed RT-PCR to understand the population level dynamics of co-existence of multiple pathogens during the monsoon season in the urban settings.

Spinal muscular atrophy (SMA) is a neuromuscular, rare genetic disorder caused due to loss-of-function mutations in the survival motor neuron-1 (SMN1) gene, leading to deficiency of the SMN protein. The severity of the disease phenotype is inversely proportional to the copy number of another gene, SMN2, that differs from SMN1 by a few nucleotides. The current diagnostic methods for SMA include symptom-based diagnosis, biochemical methods like detection of serum creatine kinase, and molecular detection of disease-causing mutations using polymerase chain reaction (PCR), multiplex ligation-dependent probe amplification (MLPA), and exome or next-generation sequencing (NGS). Along with detection of the disease-causing mutation in the SMN1 gene, it is crucial to identify the copy number of the SMN2 gene, which is a disease modifier. Therapeutic options like gene therapy, antisense therapy, and small molecules are available for SMA, but, the costs are prohibitively high. This review discusses the prevalence, diagnosis, available therapeutic options for SMA, and their clinical trials in the Indian context, and highlights the need for measures to make indigenous diagnostic and therapeutic interventions.

The One Health concept recognizes the inextricable interactions of the diverse ecosystems and their subsequent effect on human, animal and plant health. Antimicrobial resistance (AMR) is a major One Health concern and is predicted to cause catastrophes if appropriate measures are not implemented. In this study, to understand the AMR landscape in metropolitan city context, we performed metagenomic analysis of open drain wastewater samples. We analysed 17 samples from open drains that receive influx from human, animal, agricultural and industrial wastes. Our data suggests that macrolide antibiotics have developed the highest resistance in the city through mutations in the 23S rRNA gene, which is present in multiple pathogens including Escherichia coli, Campylobacter jejuni, Acinetobacter baumannii, Streptococcus pneumoniae, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Klebsiella pneumoniae and Helicobacter pylori . Except for a few geographical locations, most other locations show a similar landscape for AMR. Considering human mobility and other similar anthropogenic activities, we suggest that such an AMR landscape may be common across other regions.

Transferrin and its receptor play an important role in iron homeostasis. Binding of transferrin to its receptor (TFRC, transferrin receptor protein 1) initiates endocytic trafficking and subsequent recycling of TFRC to the plasma membrane. RAB8-positive tubules emanating from the endocytic recycling compartment play an important role in receptor recycling. However, the signaling pathways or mechanisms that mediate formation of RAB8-positive tubules are not clear. Here, we have investigated the role of transferrin-induced signaling in the regulation of RAB8- and MICAL-L1-positive tubules. Addition of transferrin to the serum starved HeLa cells resulted in enhanced recruitment of RAB8 as well as MICAL-L1 to the tubules, which was mediated by TFRC. Dynasore, an inhibitor of dynamin and endocytosis, completely blocked transferrin-induced formation of RAB8/MICAL-L1-positive tubules. RAB8 showed strong colocalization with MICAL-L1 on the tubules. Blocking of SRC or AKT kinase activity by specific inhibitors abolished transferrin-induced recruitment of RAB8 and MICAL-L1 to the tubules. Recycling of transferrin receptor was inhibited by blocking of AKT activity. TBC1D17, a GTPase activating protein for RAB8, inhibited RAB8/MICAL-L1-positive tubule formation. A phospho-mimicking mutant S366D of TBC1D17 did not inhibit formation of RAB8-positive tubules. Overall, these results show that transferrin induces TFRC mediated signaling dependent on endocytosis that is essential for the formation of RAB8- and MICAL-L1-positive tubules involved in recycling of transferrin receptor. Our results also show that AKT regulates transferrin-induced formation of RAB8- and MICAL-L1-positive tubules, which might be mediated by phosphorylation of TBC1D17.

Wastewater-based epidemiology (WBE) is emerging as a potential approach to study the infection dynamics of SARS-CoV-2 at a community level. Periodic sewage surveillance can act as an indicative tool to predict the early surge of pandemic within the community and understand the dynamics of infection and, thereby, facilitates for proper healthcare management. In this study, we performed a long-term epidemiological surveillance to assess the SARS-CoV-2 spread in domestic sewage over one year (July 2020 to August 2021) by adopting longitudinal sampling to represent a selected community (~2.5 lakhs population). Results indicated temporal dynamics in the viral load. A consistent amount of viral load was observed during the months from July 2020 to November 2020, suggesting a higher spread of the viral infection among the community, followed by a decrease in the subsequent two months (December 2020 and January 2021). A marginal increase was observed during February 2021, hinting at the onset of the second wave (from March 2021) that reached it speak in April 2021. Dynamics of the community infection rates were calculated based on the viral gene copies to assess the severity of COVID-19 spread. With the ability to predict the infection spread, longitudinal WBE studies also offer the prospect of zoning specific areas based on the infection rates. Zoning of the selected community based on the infection rates assists health management to plan and manage the infection in an effective way. WBE promotes clinical inspection with simultaneous disease detection and management, in addition to an advance warning signal to anticipate outbreaks, with respect to the slated community/zones, to tackle, prepare for and manage the pandemic.

Genetic alterations and environmental factors contribute towards pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Various types of mutations in the autophagy receptor protein optineurin (coded by OPTN gene) including deletions are causatively associated with ALS. To explore the role of OPTN in ALS pathogenesis, we used Optn knockout mice to study the features of ALS. The Optn-deficient mice did not show kyphosis, loss of body weight, weakening of front paw-grip strength or limb muscle strength. However, several Optn-deficient mice showed patchy loss of hair, which increased with age. Our results suggest that optineurin deficiency alone is not sufficient to induce ALS-like symptoms in mice. We suggest that optineurin deficiency may require cooperation with other genetic or environmental factors to cause ALS. Since endoplasmic reticulum (ER) stress plays an important role in ALS pathogenesis, and Optn modulates ER stress response signaling, Optn deficiency may contribute to ALS pathogenesis partly by potentiating ER stress response signaling.