Pathogens (Basel, Switzerland)Sep 26, 2026

mRNA Vaccine Combining PstS and YidR Protects Against Different Strains of Dangerous Klebsiella pneumoniae Infections, Including Eye Infection

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Updated Sep 27, 2026

Abstract

The PstS-YidR fusion mRNA vaccine significantly reduced systemic symptoms and bacterial spread in a mouse model of hypervirulent Klebsiella pneumoniae infection.

The vaccine suppressed bacterial dissemination across multiple tissues including the peritoneum, blood, liver, lungs, and eyes.
Excessive release of inflammatory factors IL-1β, IL-6, and TNF-α was reduced following vaccination.
Intraocular suppurative lesions were alleviated, and ocular structure was preserved.
Liver abscess formation and hepatocellular necrosis were mitigated by the vaccine.
Equal protective efficacy was observed against hypervirulent K1 and K2 strains, indicating broad effectiveness.
The vaccine demonstrated favorable safety in vivo.

Simplified

Background: Hypervirulent Klebsiella pneumoniae (K. pneumoniae) easily causes bacteremia and liver abscess, and invades the eye via blood circulation to trigger blinding endogenous endophthalmitis. Widespread multidrug resistance limits antibiotic treatment, while traditional capsular polysaccharide vaccines cannot provide cross-serotype protection. Methods: We established a mouse model of intraperitoneal infection-induced endogenous endophthalmitis. BALB/c mice received two intramuscular injections of LNP-encapsulated PstS-YidR fusion mRNA vaccine, followed by challenge with hypervirulent K1 or K2 strains. We monitored body weight, quantified multi-tissue bacterial loads, detected IL-1β, IL-6 and TNF-α, and performed slit-lamp observation and liver/ocular histopathology. Results: The vaccine relieved systemic symptoms and weight loss, suppressed bacterial dissemination across peritoneal, blood, liver, lung and eye tissues, and reduced excessive inflammatory factor release. It alleviated intraocular suppurative lesions, preserved ocular structure, and mitigated liver abscess and hepatocellular necrosis, with equal protective efficacy against K1 and K2 and favorable in vivo safety. Conclusions: The PstS-YidR fusion mRNA vaccine blocks systemic spread and intraocular invasion of hypervirulent K. pneumoniae and alleviates multi-organ inflammatory damage. It serves as a safe candidate vaccine for preventing K1/K2-type hypervirulent Klebsiella infections and endogenous endophthalmitis.

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mRNA Vaccine Combining PstS and YidR Protects Against Different Strains of Dangerous Klebsiella pneumoniae Infections, Including Eye Infection

Abstract

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