Immunogenicity of SARS-CoV-2 vaccines BBV152 (COVAXIN®) and ChAdOx1 nCoV-19 (COVISHIELD™) in seronegative and seropositive individuals in India: a multicentre, nonrandomised observational study.

Background: There are limited global data on head-to-head comparisons of vaccine platforms assessing both humoral and cellular immune responses, stratified by pre-vaccination serostatus. The COVID-19 vaccination drive for the Indian population in the age group 18-45 years began in April 2021 when seropositivity rates in the general population were rising due to the delta wave of COVID-19 pandemic during April-May 2021. Methods: Between June 30, 2021, and Jan 28, 2022, we enrolled 691 participants in the age group 18-45 years across four clinical sites in India. In this non-randomised and laboratory blinded study, participants received either two doses of Covaxin® (4 weeks apart) or two doses of Covishield™ (12 weeks apart) as per the national vaccination policy. The primary outcome was the seroconversion rate and the geometric mean titre (GMT) of antibodies against the SARS-CoV-2 spike and nucleocapsid proteins post two doses. The secondary outcome was the frequency of cellular immune responses pre- and post-vaccination. Findings: When compared to pre-vaccination baseline, both vaccines elicited statistically significant seroconversion and binding antibody levels in both seronegative and seropositive individuals. In the per-protocol cohort, Covishield™ elicited higher antibody responses than Covaxin® as measured by seroconversion rate (98.3% vs 74.4%, p < 0.0001 in seronegative individuals; 91.7% vs 66.9%, p < 0.0001 in seropositive individuals) as well as by anti-spike antibody levels against the ancestral strain (GMT 1272.1 vs 75.4 binding antibody units/ml [BAU/ml], p < 0.0001 in seronegative individuals; 2089.07 vs 585.7 BAU/ml, p < 0.0001 in seropositive individuals). As participants at all clinical sites were not recruited at the same time, site-specific immunogenicity was impacted by the timing of vaccination relative to the delta and omicron waves. Surrogate neutralising antibody responses against variants-of-concern including delta and omicron was higher in Covishield™ recipients than in Covaxin® recipients; and in seropositive than in seronegative individuals after both vaccination and asymptomatic infection (omicron variant). T cell responses are reported from only one of the four site cohorts where the vaccination schedule preceded the omicron wave. In seronegative individuals, Covishield™ elicited both CD4+ and CD8+ spike-specific cytokine-producing T cells whereas Covaxin® elicited mainly CD4+ spike-specific T cells. Neither vaccine showed significant post-vaccination expansion of spike-specific T cells in seropositive individuals. Interpretation: Covishield™ elicited immune responses of higher magnitude and breadth than Covaxin® in both seronegative individuals and seropositive individuals, across cohorts representing the pre-vaccination immune history of most of the vaccinated Indian population. Funding: Corporate social responsibility (CSR) funding from Hindustan Unilever Limited (HUL) and Unilever India Pvt. Ltd. (UIPL).

Anaerobic growth and drug susceptibility of versatile fungal pathogen Scedosporium apiospermum.

Although severe cases of invasive mycoses of different hypoxic and anoxic body parts have been reported, growth and drug susceptibility of fungal pathogens under anaerobic conditions remains understudied. The current study evaluated anaerobic growth potential and drug susceptibility of environmental Scedosporium apiospermum isolates under aerobic and anaerobic conditions. All tested strains showed equivalent growth and higher sensitivity to tested antifungal drugs under anaerobic conditions with lower minimum inhibitory concentration (MIC) as compared to aerobic conditions. Antifungal azoles were effective against isolates under both aerobic and anaerobic conditions. Most strains were resistant to antifungal echinocandins and polyenes under aerobic conditions but exhibited sensitivity under anaerobic conditions. This study provides evidence that resistance of S. apiospermum to antifungal drugs varies with oxygen concentration and availability and suggests re-evaluating clinical breakpoints for antifungal compounds to treat invasive fungal infections more effectively.

Microbial Population Dynamics in Lemnaceae (Duckweed)-Based Wastewater Treatment System.

The dynamic microflora associated within, and in the surrounding aquatic environment, has been found to be responsible for the functional properties of many aquatic plants. The aim of the current work was to evaluate the effectiveness of Lemnaceae-based wastewater treatment system under tropical conditions and investigate the changes in the aquatic microflora upon plant growth. A biological wastewater treatment system was designed and investigated using mixed Lemnaceae culture comprising Lemna minor and Spirodela polyrhiza in a batch mode. A significant reduction in total solids (31.8%), biochemical oxygen demand (93.5%), and chemical oxygen demand (73.2%) was observed after seven days of duckweed growth using a low inoculum. A preliminary study on the change in the microbial population diversity and functionality, in the wastewater before and after treatment, revealed an increase in the denitrifying microflora in wastewater post-Lemnaceae treatment. Dominance of 10 bacterial phyla, contributing for 98.3% of the total bacterial communities, was recorded, and ~ 50.6% loss of diversity post-treatment of wastewater was revealed by the Shannon Index. Among 16 bacterial families showing relative abundance of ≥ 1% in untreated wastewater, Methylobacteriaceae, Pseudomonadaceae, Brucellaceae, Rhodobacteraceae, and Acetobacteraceae prevailed in the water post-treatment by duckweeds. This is a novel work done on the dynamics of aquatic microflora associated with Lemnaceae under tropical Indian conditions. It confirms the application of Lemnaceae-based wastewater treatment system as effective biofilter and calls for further studies on the active involvement of the endophytic and aquatic microflora in the functions of these plant.

Percent positivity and phylogenetic analysis of Mycoplasma gallisepticum and Mycoplasma synoviae in commercial poultry from the different States of India.

Background and Aim: The Indian and global poultry industries suffer significant economic losses due to Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) infections, which adversely affect egg production, hatchability, weight gain, and feed efficiency in farms, thus decreasing the overall production efficiency. This study aimed to determine the percent positivity and phylogenetic analysis of MG, MS, and co-infection of both mycoplasmas in commercial poultry farms across different states of India from 2017 to 2021. Materials and Methods: A total of 3620 tracheal or choacal swabs were collected from breeder and layer farms showing clinical signs of avian mycoplasma infections from commercial poultry farms across India, and the percent positivity for MG, MS, and co-infection of both mycoplasmas were determined by Polymerase chain reaction using the 16S rRNA and vlhA genes amplification, respectively. Phylogenetic analysis was carried out by sequencing the mgc2 and vlhA genes of 2 samples of MG and 24 samples of M. synoviae to gain insight into the genetic variability of Indian strains. The data were then compared with other Indian strains, vaccines strains, and strains from other countries. Results: Our data shows the percent positivity of MG, MS, and co-infection of both MG and MS was 6.43%, 23.61%, and 15.49%, respectively. The phylogenetic relationship between MG and MS was determined using the vlhA and mgc2 genes, revealing two samples of MG and 24 samples of MS clustered with other Indian strains. M. synoviae MSM22 and previously studied M. synoviae MGS 482 clustered with vaccine strain M. synoviae MS-H. Conclusion: Mycoplasma synoviae infections in breeder, layer, and in both is predominant compared to MG across the states investigated in India. Sequenced samples of MG and MS showed evolutionary relationships with the previously studied Indian strains of MG and MS. These findings support our view that monitoring chickens for avian mycoplasma infections are of paramount significance. It further lends credence to the contention that such information will pave the way for the development of a home-grown vaccination control program and thus safeguard the poultry sector against mycoplasma infections.

Oligotrophy vs. copiotrophy in an alkaline and saline habitat of Lonar Lake.

We reported our comparative observations on oligotrophs vs. copiotrophs from a hyper-alkaline and hypersaline habitat, Lonar Lake, situated in the Buldhana district of Maharashtra, India. Cell numbers of oligotrophic and copiotrophic microbes from the sediment were enumerated by the three-tube most probable number (MPN) method using an array of nutrient-rich and oligotrophic (≈10-20 mg carbon L-1) media offering simulated natural conditions of pH and salinity. A total of 50 strains from 15 different genera and 30 different species were isolated from the highest positive dilutions of MPN to identify the taxa of oligotrophs and copiotrophic microorganisms dominating in Lonar Lake. We did not get any true oligotrophs due to their adaptation to higher carbon levels during the isolation procedure. On the contrary, several true copiotrophs, which could not adapt and survive on a low-carbon medium, were isolated. It is also observed that changes in medium composition and nutrient level altered the selection of organisms from the same sample. Our data indicate that copiotrophic microorganisms dominate the eutrophic Lonar Lake, which is also supported by the past metagenomics studies from the same site. We also reported that quick depletion of carbon from oligotrophic medium worked as a limiting factor, inducing cell death after 2-3 generations and preventing the development of visible colonies on plates and sufficient optical density in liquid medium. Therefore, a long-term supply of low levels of carbon, followed by isolation on enriched media, can serve as a good strategy in isolation of novel taxa of microorganism, with industrial or environmental importance.

Effect of Encapsulated Ferrous Sulphate Fortified Salt on Hemoglobin Levels in Anemic Rats.

(1) Background: Iron deficiency anemia is a significant nutritional problem all over the world. Salt formulations supplemented with encapsulated iron and iodine (double-fortified) were tested for their efficacy in managing iron deficiency anemia. In this study, we have checked the effect of these double-fortified salt formulations (iron and iodine) on hemoglobin (Hb) levels in anemic Wistar male rats. (2) Methods: The study was divided into two phases, viz., the development of anemia in the first phase and then the random division of anemic rats into five groups (Groups A to E). These rats were fed with three different salt formulations (Groups A to C); Group D was continued on a low iron diet, and Group E was on a normal pellet diet over a period of 84 days. The level of Hb was tested in each group. (3) Results: The rats in Groups A, B, C, and E recovered from anemia significantly, with higher Hb levels. On day 84, however, the Hb level in Group D continued to decrease. The bodyweight of the rats was not affected in any way. In all of the groups, histopathology examinations in various organs revealed no significant changes. (4) Conclusions: All of the three different salt formulations showed significant recovery in the anemic rats as compared to the rats fed with a normal pelleted diet.

Recent trend, biases and limitations of cultivation-based diversity studies of microbes.

The current study attempts to analyze recent trends, biases and limitations of cultivation-based microbial diversity studies based on published, novel species in the past 6 years in the International Journal of Systematic and Evolutionary Microbiology (IJSEM), an official publication of the International Committee on Systematics of Prokaryotes (ICSP) and the Bacteriology and Applied Microbiology (BAM) Division of the International Union of Microbiological Societies (IUMS). IJSEM deals with taxa that have validly published names under the International Code of Nomenclature of Prokaryotes (ICNP). All the relevant publications from the last 6 years were retrieved, sorted and analyzed to get the answers to What is the current rate of novel species description? Which country has contributed substantially and which phyla represented better in culturable diversity studies? What are the current limitations? Published data for the past 6 years indicate that 500-900 novel species are reported annually. China, Korea, Germany, UK, India and the USA are at the forefront while contributions from other nations are meager. Despite the recent development in culturomics tools the dominance of Proteobacteria, Bacteroidetes and Actinobacteria are still prevalent in cultivation, while the representation of archaea, obligate anaerobes, microaerophiles, synergistic symbionts, aerotolerant and other fastidious microbes is poor. Single strain-based taxonomic descriptions prevail and emphasis on objective-based cultivation for biotechnological and environmental significance is not yet conspicuous.

Antimicrobial resistance pattern of microorganisms isolated and identified from Godavari River across the mass gathering event.

The Kumbh Mela is considered the world's largest mass gathering event (MGE). It represents a unique anthropogenic burden on the river ecosystem and may confer antimicrobial resistance among microbial communities. The present study explains the characterization of microbial isolates associated with Godavari River under the advent of the mass bathing event using culture dependent approach. The isolates were identified by sequencing of 16S rRNA gene and ITS region. Further, the isolates were screened for antibiotic susceptibility against 22 antibiotics using disc diffusion method. A total of 63 bacterial and 21 fungal isolates were isolated under the temporal variation of the event. Kocuria and Staphylococcus were the most prevalent bacterial genera in the samples collected before and during the event, while Meyerozyma and Candida predominate among fungal communities. A group of antibiotics impeding the bacterial protein synthesis were found to be most effective against greater than or equal to 67% of bacterial isolates. However, greater than or equal to 37-67% of isolates could escape the action of inhibitors of bacterial cell wall synthesis. Moreover, bacterial isolates belonging to genera Acinetobacter, Corynebacterium and Brevibacterium showed higher resistance towards the antibiotics. Observations from the current study suggest likely microbial taxa as targets to mitigate the waterborne infections during the MGE.

Chakrabartia godavariana gen. nov., sp. nov., a novel member of the family Sphingomonadaceae isolated from the Godavari River, India.

A Gram-stain-negative, aerobic, yellow-pigmented, oxidase-positive and rod-shaped bacterium, designated PRB40T, was isolated from the Godavari River in India during the course of 'Kumbh Mela', the world's largest mass gathering event. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain PRB40T formed a lineage within the family Sphingomonadaceae and was distinct from the most closely related genera Sphingorhabdus, Novosphingobiumand Sphingomonas with sequence similarity values ≤95.2 %. Growth of strain PRB40T occurred at 10-40 °C (optimum 30 °C), at pH 6.0-9.0 (pH 7.0) and with 0-0.5 % (w/v) NaCl concentration (0 %). The major respiratory quinone was ubiquinone-10 (Q-10). It contained C17 : 1ω6c, C14 : 0 2-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) as the major cellular fatty acids. The predominant polar lipids were phospholipid, phosphatidylethanolamine and sphingoglycolipid. It took sym-homospermidine as the major polyamine. The DNA G+C content based on its draft genome sequence was 63.7 mol%. The polyphasic taxonomic analyses indicated that strain PRB40T represents a novel species of a novel genus within the family Sphingomonadaceae, for which the name Chakrabartia godavariana gen. nov., sp. nov. is proposed. The type strain of Chakrabartia godavariana is PRB40T (=MCC 3406T=GDMCC 1.1197T=KCTC 52678T=LMG 29985T).

World's Largest Mass Bathing Event Influences the Bacterial Communities of Godavari, a Holy River of India.

Kumbh Mela is one of the largest religious mass gathering events (MGE) involving bathing in rivers. The exponential rise in the number of devotees, from around 0.4 million in 1903 to 120 million in 2013, bathing in small specified sites can have a dramatic impact on the river ecosystem. Here, we present the spatiotemporal profiling of bacterial communities in Godavari River, Nashik, India, comprising five sites during the Kumbh Mela, held in 2015. Assessment of environmental parameters indicated deterioration of water quality. Targeted amplicon sequencing demonstrates approximately 37.5% loss in microbial diversity because of anthropogenic activity during MGE. A significant decrease in phyla viz. Actinobacteria, Chloroflexi, Proteobacteria, and Bacteroidetes was observed, while we noted substantial increase in prevalence of the phylum Firmicutes (94.6%) during MGE. qPCR estimations suggested nearly 130-fold increase in bacterial load during the event. Bayesian mixing model accounted the source of enormous incorporation of bacterial load of human origin. Further, metagenomic imputations depicted increase in virulence and antibiotic resistance genes during the MGE. These observations suggest the striking impact of the mass bathing on river ecosystem. The subsequent increase in infectious diseases and drug-resistant microbes pose a critical public health concern.

Corynebacterium godavarianum sp. nov., isolated from the Godavari river, India.

A Gram-stain-positive, rod-shaped, non-motile bacterium, strain PRD07T, was isolated from Godavari river, India during the world's largest spiritual and religious mass bathing event 'Kumbh Mela'. Molecular analysis using 16S rRNA gene sequencing and phylogenetic analysis reveals the distinct phylogenetic positioning of strain PRD07T within the genus Corynebacterium. The strain demonstrated highest sequence similarity to Corynebacterium imitans DSM 44264T (97.9 %), Corynebacterium appendicis DSM 44531T (97.1 %) and <96.7 % with all other members of the genus Corynebacterium. The G+C content of PRD07T was 68.5 mol% (Tm) and the DNA-DNA hybridization depicts 61.09 % genomic relatedness with C. imitans DSM 44264T. Chemotaxonomic assessment of strain PRD07T suggested presence of C16 : 0 (31.6 %), C18 : 0 (3.5 %) and C18 : 1ω9c (58.6 %) as the major cellular fatty acids. The major polar lipids of strain PRD07T were phosphatidylglycerol, diphosphatidylglycerol and glycophospholipid. Differentiating molecular, phylogenetic and chemotaxonomic characteristics of strain PRD07T with its closest relatives necessitated the description of strain PRD07T as a novel species of genus Corynebacterium for which the name Corynebacteriumgodavarianum sp. nov., has been proposed. The type strain is PRD07T (=MCC 3388T=KCTC 39803T=LMG 29598T).