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Bacterial Type VI Secretion System (T6SS) Driven Microbial Warfare for Improving Gut Health
Volume 11| Issue 2 | December 2025
AUTHOR(S)
Aditya Ghosh, Subhadeep Gupta, Prakash Biswas, Amirul Islam Mallick

ABSTRACT

Campylobacter jejuni (C. jejuni) is a leading cause of foodborne diseases, with poultry serving as a major source of transmission. Like other Gram-negative pathogens, C. jejuni employs diverse toxin secretion systems, including the recently characterized Type VI Secretion System (T6SS), to facilitate pathogenesis, self-survival, and interspecies competition in the gut environment. Our previous findings demonstrated that C. jejuni T6SS functionality can induce “self-depletion” when interacting with appropriate target cells, such as E. coli, particularly under environmental stress. We hypothesized that exploiting T6SS-driven “predation cost” could improve gut health by employing selective targets or interacting bacteria. Using in vitro co-culture assays with the probiotic Lactobacillus johnsonii (L. johnsonii), revealed significant growth inhibition and membrane damage in T6SS-positive C. jejuni compared to T6SS-negative strains. This differential response was associated with a modest increase in the release of hemolysin co-regulated protein (Hcp), a hallmark of T6SS effector. Scanning electron microscopy further revealed surface damage consistent with bacteriocin-mediated stress. We propose that the activation of T6SS may have some role in sensitizing C. jejuni to anti-microbial metabolites or bacteriocins produced by L. johnsonii, enhancing the vulnerability of the bacteria. These findings underscore the potential of manipulating microbial competition and T6SS dynamics as a novel strategy for gut microbiota modulation and pathogen control.

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DOI
https://www.doi.org/10.62418/ijvph.11.2.2025.15-22
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Corresponding author’s email ID: amallick@iiserkol.ac.in
Citation: Ghosh A, Gupta S, Biswas P, Mallick AI. Bacterial Type VI Secretion System (T6SS) Driven Microbial Warfare for Improving Gut Health. Indian Journal of Veterinary Public Health. 2025; 11(2): 15-22.
DOI: https://www.doi.org/10.62418/ijvph.11.2.2025.15-22