Intrinsic insights to antimicrobial effects of Nitrofurantoin to multi drug resistant Salmonella enterica serovar Typhimurium ms202.

Emerging multidrug resistant (MDR) serovar of Salmonella has raised the concern of their impactful effect on pathogenic infection and mortality in human lead by the enteric diseases. In order to combat the battle against these MDR Salmonella pathogen, new drug molecules need to be evaluated for their potent antibacterial application. This study evaluates the mechanistic antimicrobial effect of nitrofurantoin against a MDR strain of Salmonella named S. enterica Typhimurium ms202. The antimicrobial effect of nitrofurantoin was studied through experimental and computational approach using standard microbiological and molecular techniques like growth curve analysis, live-dead analysis, oxidative stress evaluation using high throughput techniques like flow cytometry and fluorescent microscopy. The result showed a potent dose dependent antibacterial effect of nitrofurantoin against S. enterica Typhimurium ms202 with a MIC value of 64 µg/ml. Moreover, the mechanistic excavation of the phenomenon described the mechanism as an effect of molecular interaction of nitrofurantoin molecule with membrane receptor proteins OmpC of S. enterica Typhimurium ms202 leading to internalization of the nitrofurantoin heading towards the occurrence of cellular physiological disturbances through oxidative stress impeded by nitrofurantoin-Sod1 C protein interaction. The results indicated towards a synergistic effect of membrane damage, oxidative stress and genotoxicity for the antibacterial effect of nitrofurantoin against S. enterica Typhimurium ms202. The study described the potent dose-dependent application of nitrofurantoin molecule against MDR strains of Salmonella and guided towards their use in further discovered MDR strains.

Genome analysis and virulence gene expression profile of a multi drug resistant Salmonella enterica serovar Typhimurium ms202.

BACKGROUND: In India, multi-drug resistance in Salmonella enterica serovar Typhimurium poses a significant health threat. Indeed, S. Typhimurium has remained unknown for a large portion of its genome associated with various physiological functions including mechanism of drug resistance and virulence. The whole-genome sequence of a Salmonella strain obtained from feces of a patient with gastroenteritis in Odisha, India, was analyzed for understanding the disease association and underlying virulence mechanisms. RESULTS: The de novo assembly yielded 17 contigs and showed 99.9% similarity to S. enterica sub sp enterica strain LT2 and S. enteric subsp salamae strain DSM 9220. S. Typhimurium ms202 strain constitutes six known Salmonella pathogenicity islands and nine different phages. The comparative interpretation of pathogenic islands displayed the genes contained in SPI-1 and SPI-2 to be highly conserved. We identified sit ABCD cluster regulatory cascade in SPI-1. Multiple antimicrobial resistance genes were identified that directly implies antibiotic-resistant phenotype. Notably, seven unique genes were identified as "acquired antibiotic resistance". These data suggest that virulence in S. enterica Typhimurium ms202 is associated with SPI-1 and SPI-2. Further, we found several virulent genes encoding SPI regions belonging to type III secretion systems (T3SS) of bacteria were significantly upregulated in ms202 compared to control LT2. Moreover, all these genes were significantly downregulated in S. enterica Typhimurium ms202 as compared to control LT2 on adding Mn2+ exogenously. CONCLUSIONS: Our study raises a vital concern about the potential diffusion of a novel multi-drug resistant S. enterica Typhimurium ms202. It justifies this clinical pathogen to demonstrate a higher degree survival due to higher expression of virulent genes and enhanced ability of metallic ion acquisition.

Prevalence and multidrug resistance in Salmonella enterica Typhimurium: an overview in South East Asia.

Acute/chronic gastroenteritis is caused by a few serovars of Salmonella enterica. Among different serovars, S. enterica Typhimurium is a potent pathogen that contributes significantly to self-limiting diarrhea related mortality worldwide. With no successful vaccine in hand against this pathogen, antibiotics are used as for gold standard for treatment against Salmonella induced gastroenteritis. Indispensably, rise in multi drug resistance against Salmonella Typhimurium poses challenge to treatment options. South East Asia, with 11 different countries, stands 3rd as super region for global burden of Salmonella induced gastroenteritis. In this review, we made an attempt to discuss on prevalence and multidrug resistance in Salmonella Typhimurium in 11 countries of South East Asia-the issue that has not been seriously addressed so far. By thorough analysis of reported data, we found varying frequencies for prevalence of Salmonella Typhimurium as well as subtle evidences on resistance of this pathogen to multiple antibiotics in different countries. Vietnam ranked top in terms of reports for prevalence and antimicrobial resistance. However, in countries such as Brunei and Timor Leste, no study has been performed so far to track the frequency of incidence and drug resistance of this pathogen. Our review, the first of its kind, emphasizes that, although the pathogen was not found as dominant serovar in South East Asia in last 20 years unlike sub-Saharan Africa, it may be still considered as a major threat in this region due to available evidences for infection in humans as well as contamination in several animal and food sources. More importantly, the importance as a public threat in this subregion of Asia is also due to resistance of this pathogen to multiple antibiotics. South East Asian countries showing incidence and multi drug resistance of Salmonella enterica Typhimurium in human and non-human sources (1969-2020). -Drug resistant S. enterica Typhimurium.

Role of OB-Fold Protein YdeI in Stress Response and Virulence of Salmonella enterica Serovar Enteritidis.

An essential feature of the pathogenesis of the Salmonella enterica serovar Enteritidis wild type (WT) is its ability to survive under diverse microenvironmental stress conditions, such as encountering antimicrobial peptides (AMPs) or glucose and micronutrient starvation. These stress factors trigger virulence genes carried on Salmonella pathogenicity islands (SPIs) and determine the efficiency of enteric infection. Although the oligosaccharide/oligonucleotide binding-fold (OB-fold) family of proteins has been identified as an important stress response and virulence determinant, functional information on members of this family is currently limited. In this study, we decipher the role of YdeI, which belongs to OB-fold family of proteins, in stress response and virulence of S Enteritidis. When ydeI was deleted, the ΔydeI mutant showed reduced survival during exposure to AMPs or glucose and Mg2+ starvation stress compared to the WT. Green fluorescent protein (GFP) reporter and quantitative real-time PCR (qRT-PCR) assays showed ydeI was transcriptionally regulated by PhoP, which is a major regulator of stress and virulence. Furthermore, the ΔydeI mutant displayed ∼89% reduced invasion into HCT116 cells, ∼15-fold-reduced intramacrophage survival, and downregulation of several SPI-1 and SPI-2 genes encoding the type 3 secretion system apparatus and effector proteins. The mutant showed attenuated virulence compared to the WT, confirmed by its reduced bacterial counts in feces, mesenteric lymph node (mLN), spleen, and liver of C57BL/6 mice. qRT-PCR analyses of the ΔydeI mutant displayed differential expression of 45 PhoP-regulated genes, which were majorly involved in metabolism, transport, membrane remodeling, and drug resistance under different stress conditions. YdeI is, therefore, an important protein that modulates S Enteritidis virulence and adaptation to stress during infection.IMPORTANCES Enteritidis during its life cycle encounters diverse stress factors inside the host. These intracellular conditions allow activation of specialized secretion systems to cause infection. We report a conserved membrane protein, YdeI, and elucidate its role in protection against various intracellular stress conditions. A key aspect of the study of a pathogen's stress response mechanism is its clinical relevance during host-pathogen interaction. Bacterial adaptation to stress plays a vital role in evolution of a pathogen's resistance to therapeutic agents. Therefore, investigation of the role of YdeI is vital for understanding the molecular basis of regulation of Salmonella pathogenesis. In conclusion, our findings may contribute to finding potential targets to develop new intervention strategies for treatment and prevention of enteric diseases.

Major enteropathogens in humans, domestic animals, and environmental soil samples from the same locality: prevalence and transmission considerations in coastal Odisha, India.

OBJECTIVES: Regions with limited sanitation facilities have higher rates of infections with various enteric pathogens. It is therefore important to identify different hosts and their relative contribution to pathogen shedding into the environment, and to assess the subsequent health risks to humans. METHODS: In this study, human faecal (n=310), animal faecal (n=150), and environmental (soil) samples (n=40) were collected from the same locality and screened for selected enteric pathogens by immunochromatography and/or polymerase chain reaction. RESULTS: At least 1 microbial agent was detected in 49.0%, 44.7%, and 40.0% of the samples from human, animals, and soil, respectively. Among humans, rotavirus was predominantly detected (17.4%) followed by enteropathogenic Escherichia coli (EPEC) (15.4%), Shigella (13.8), and Shiga toxin-producing E. coli (STEC) (9.7%). Among animals, STEC was detected most frequently (28.0%), and EPEC was the major enteric pathogen detected in soil (30.0%). The detection rate of rotavirus was higher among younger children (≤2 years) than among older children. Single infections were more commonly detected than multiple infections in humans (p<0.01), unlike the observations in animal and soil samples. For diarrhoeagenic E. coli and Shigella, most of the human and animal isolates showed close relatedness, suggesting possible cross-infection between humans and domesticated animals in the area studied. CONCLUSIONS: The present study provides an improved understanding of the distribution of major enteric pathogens coexisting in humans and animals in the region, thereby suggesting a high potential for possible transmission among livestock and communities residing in the studied locality.

Is Lower Vitamin D Level Associated with Increased Risk of Neonatal Sepsis? A Prospective Cohort Study.

OBJECTIVE: To evaluate the effect of maternal/ neonatal vitamin D levels on culture positive neonatal sepsis. METHODS: This prospective cohort study was conducted in the NICU of a tertiary care teaching hospital in Odisha, Eastern India from January 2015 through December 2016. Forty (40) neonates with culture positive sepsis were included in the study group. Forty (40) healthy neonates admitted for evaluation of neonatal jaundice who are similar in gender, gestational age, postnatal age and without any clinical signs of sepsis were recruited as control group after informed consent. Vitamin D level (25 OH D) was assessed in the neonates and their mothers in both the groups. RESULTS: Neonatal 25 OH vitamin D level in the study group (12.71 ± 2.82 ng/ml) was significantly lower than in the control group (25.46 ± 7.02 ng/ml). The Odds ratio was 273 (95% CI 30.39-2451.6) for culture positive sepsis in neonates with vitamin D deficiency/insufficiency. Mothers of septic neonates had significantly lower 25 OH vitamin D level (20.92 ± 3.92 ng/ml) than the mothers of healthy neonates in control group (27.31 ± 6.83 ng/ml). The Odds ratio was 4.71 (95% CI 1.69-13.1) for culture positive sepsis in babies born to mothers with vitamin D deficiency/insufficiency. CONCLUSIONS: Neonates with vitamin D deficiency/insufficiency are at higher risk for developing sepsis than those with sufficient vitamin D levels. Lower vitamin D levels in mothers is also associated with increased risk of sepsis in the neonates.

Detection and molecular typing of campylobacter isolates from human and animal faeces in coastal belt of Odisha, India.

Introduction: Campylobacter-mediated diarrhoea is one of the major causes of gastroenteritis globally. A majority of the Campylobacter spp. that cause disease in humans have been isolated from animals. Faecal contamination of food and water is the identified frequent cause of human campylobacteriosis. Methodology: In the present study, faecal samples from patients with symptoms of acute diarrhoea (n = 310) and domestic animals including cows (n = 60), sheep (n = 45) and goats (n = 45) were collected from the same localities in the peri-urban Bhubaneswar city. Genomic DNA isolation followed by polymerase chain reaction and sequencing was employed to analyse Campylobacter spp.-positive samples. Results: Of the 460 faecal samples, 16.77% of human samples and 25.33% of animal samples were found to be positive for Campylobacter spp. Among animals, the isolation rate was highest in sheep followed by cows and goats with 9.33%, 8.66% and 7.33%, respectively. The highest number of Campylobacter-positive cases was diagnosed in infants of 2-5 years age. Concurrent infection of other pathogens in addition to Campylobacter spp. was frequently detected in the samples. Conclusion: The present study showed the incidence of Campylobacter infections in human and different animal species in and around Bhubaneswar, Odisha. The analysis suggested that domestic animals can be the potential sources for human campylobacteriosis in the region.