Publications by authors named "Hemanta Koley"

Carbapenem resistance mediated by -encoded metallo-beta-lactamases is often linked to IS, an insertion sequence from the IS family, which is widely distributed among critical and high-priority bacterial pathogens. The rapid dissemination of IS-linked in both nosocomial and community-acquired infections presents a serious challenge to healthcare systems and pharmaceutical industries. Despite the urgency of this issue, the factors driving spread and the molecular mechanisms governing IS mobility remain poorly understood.

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Enteroinvasive Escherichia coli (EIEC), known for causing bacillary dysentery akin to Shigella species, comprises both lactose-fermenting (LF) and non-lactose-fermenting (NLF) isolates. While NLF-EIEC is a well-established pathogen associated with acute dysentery and harbours classical Shigella-like virulence factors, the role of LF-EIEC in human disease remains underexplored. In this study, we sought to characterize LF-EIEC clinical isolates and assessed their pathogenic potential in comparison to NLF-EIEC.

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Unlabelled: Cholera, a diarrheal disease caused by the gram-negative bacterium , remains a global health threat in developing countries due to its high transmissibility and increased antibiotic resistance. There is a pressing need for alternative strategies, with an emphasis on anti-virulent approaches to alter the outcome of bacterial infections, given the increase in antimicrobial-resistant strains. causes cholera by secreting virulence factors in the intestinal epithelial cells.

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Vaccination plays a critical role in public health by reducing the incidence and prevalence of infectious diseases. The efficacy of a vaccine has numerous determinants, which include age, sex, genetics, environment, geographic location, nutritional status, maternal antibodies, and prior exposure to pathogens. However, little is known about the role of gut microbiome in vaccine efficacy and how it can be targeted through dietary interventions to improve immunological responses.

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infection poses a significant public health challenge in the developing world. However, lack of a widely available mouse model that replicates human shigellosis creates a major bottleneck to better understanding of disease pathogenesis and development of newer drugs and vaccines. BALB/c mice pre-treated with streptomycin and iron (FeCl) plus desferrioxamine intraperitoneally followed by oral infection with virulent resulted in diarrhea, loss of body weight, bacterial colonization and progressive colitis characterized by disruption of epithelial lining, loss of crypt architecture with goblet cell depletion, increased polymorphonuclear infiltration into the mucosa, submucosal swelling (edema), and raised proinflammatory cytokines and chemokines in the large intestine.

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Campylobacter and invasive non-typhoidal Salmonella (iNTS) are among the most common causative agents of gastroenteritis worldwide. As of now, no single combination licensed vaccine is available for public health use against both iNTS and Campylobacter species. Outer-membrane vesicles (OMVs) are nanoscale proteoliposomes released from the surface of gram-negative bacteria during log phase and harbor a variety of immunogenic proteins.

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Article Synopsis
  • * This study tested the FDA-approved antibiotic minocycline as a potential antiviral against different IAV strains and found that it effectively inhibits viral replication without being toxic.
  • * Minocycline's antiviral action targets the MEK/ERK signaling pathway, blocks the assembly and release of new virus particles, and reduces late-stage cell death caused by the virus, highlighting its potential as an alternative treatment for IAV.
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The dynamic interface between invading viral pathogens and programmed cell death (PCD) of the host is a finely regulated process. Host cellular demise at the end of the viral life cycle ensures the release of progeny virions to initiate new infection cycles. Rotavirus (RV), a diarrheagenic virus with double-stranded RNA genome, has been reported to trigger different types of PCD such as apoptosis and pyroptosis in a highly regulated way to successfully disseminate progeny virions.

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Chronic gastritis is one of the major symptoms of gastro-duodenal disorders typically induced by Helicobacter pylori (H. pylori). To date, no suitable model is available to study pathophysiology and therapeutic measures accurately.

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Background: Salmonella enterica serotype Typhi is one of the major pathogens causing typhoid fever and a public health burden worldwide. Recently, the increasing number of multidrug-resistant strains of Salmonella spp. has made this utmost necessary to consider bacteriophages as a potential alternative to antibiotics for S.

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Diarrhoeagenic Escherichia coli (DEC) pathotypes are one of the major causative agents of diarrhoea induced childhood morbidity and mortality in developing countries. Licensed vaccines providing broad spectrum protection against DEC mediated infections are not available. Outer membrane vesicles (OMVs) are microvesicles released by gram-negative bacteria during the growth phase and contain multiple immunogenic proteins.

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Typhoid and emerging paratyphoid fever are a severe enteric disease worldwide with high morbidity and mortality. Licensed typhoid vaccines are in the market, but no paratyphoid vaccine is currently available. In the present study we developed a bivalent vaccine against Salmonella Typhi and Paratyphi A using a bacterial ghost platform.

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Article Synopsis
  • The study focused on a patient with diarrhea linked to extensively drug-resistant bacteria, using disk diffusion to test for antimicrobial susceptibility.
  • The genome sequencing revealed 76 genes related to antibiotic resistance and potential virulence factors, indicating a broad resistance profile.
  • The findings suggest that the patient's diarrhea was likely due to antibiotic-associated dysbiosis, exacerbated by the pathogen's toxicity, potentially linked to its type three secretion system (T3SS).
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The widespread increase in broad-spectrum antimicrobial resistance is making it more difficult to treat gastrointestinal infections. Enteroinvasive is a prominent etiological agent of bacillary dysentery, invading via the fecal-oral route and exerting virulence on the host via the type III secretion system. IpaD, a surface-exposed protein on the T3SS tip that is conserved among EIEC and , may serve as a broad immunogen for bacillary dysentery protection.

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Background: No commercial vaccines are available against drug-resistant Shigella due to serotype-specific/narrow-range of protection. Nanoparticle-based biomimetic vaccines involving stable, conserved, immunogenic proteins fabricated using facile chemistries can help formulate a translatable cross-protective Shigella vaccine. Such systems can also negate cold-chain transportation/storage thus overcoming challenges prevalent in various settings.

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In today's world and mostly in low and middle income countries, Shigella flexneri and Shigella sonnei remains the major causative agent of clinical bacillary dysentery. Based on contemporary epidemiology, a tetravalent Outer Membrane Vesicle (OMVs) based immunogen was formulated using the most commonly circulating Shigella strains, namely, S. flexneri 2a, S.

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Background: Rotavirus is the foremost cause of acute gastroenteritis among infants in resource-poor countries, causing severe morbidity and mortality. The currently available rotavirus vaccines are effective in reducing severity of the disease but not the infection rates, thus antivirals as an adjunct therapy are needed to reduce the morbidity in children. Viruses rely on host cellular machinery for nearly every step of the replication cycle.

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Shigellosis, caused by the bacteria , is the leading cause of bacterial diarrhea and the second leading cause of diarrheal death among children under the age of five. Unfortunately, strains have acquired resistance to antibiotics, and a commercial vaccine is yet to be available. We have previously demonstrated that serotype 1 (Sd1)-based recombinant, stabilized, "invasion plasmid antigen C" (IpaC; 42 kDa) protein can induce robust immune responses in BALB/c mice against a challenge of a high dose of heterologous when immunized via three intranasal doses of IpaC without an adjuvant.

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Non-typhoidal serotypes are well adapted to utilize the inflammation for colonization in the mammalian gut mucosa and cause loss of the integrity of the epithelial barrier in the mammalian intestine. The present study assessed the protective efficacy of fish oil-in-water nanoemulsion, compared to the conventional emulsion, towards the intestinal epithelial barrier against invasive infection of serovar Typhimurium strain SL1344 in an streptomycin-treated mouse model. Non-typhoidal serovar Typhimurium strain SL1344 expresses its invasiveness by creating extreme inflammatory assault in the mammalian host lumen its repertoire of secretory or membrane-bound proteins.

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Rotavirus (RV) is the leading cause of acute gastroenteritis and watery diarrhea in children under 5 years accounting for high morbidity and mortality in countries with poor socioeconomic status. Although vaccination against RV has been implemented in more than 100 countries, the efficacy of vaccine has been challenged in low-income settings. The lack of any FDA-approved drug against RV is an additional concern regarding the treatment associated with rotavirus-induced infantile death.

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Shigellosis has been a menace to society for ages. The absence of an effective vaccine against , improper sanitation, and unhygienic use of food and water allow the disease to flourish. can also be transmitted via natural water bodies.

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Poultry animals act as natural reservoirs of invasive non-typhoidal Salmonella [iNTS] serovars and consumption of iNTS contaminated poultry meat and eggs is one of the major sources of iNTS infection in developed and developing countries. Irrational use of antibiotics in the poultry industry gives rise to the global emergence of multi drug resistant iNTS strains. Among different strategies to control iNTS infection in poultry farms, vaccination is now being widely used.

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With the acquirement of antibiotic resistance, has resulted in multiple epidemics of shigellosis, an infectious diarrheal disease, causing thousands of deaths per year. Unfortunately, there are no licensed vaccines, primarily due to low or serotype-specific immunogenicity. Thus, conserved subunit vaccines utilizing recombinant invasion plasmid antigens (Ipa) have been explored as cross-protective vaccine candidates.

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