Meszaros, L. | Search bioRxiv

bioRxiv2026

A preclinical resistance framework discovers the virulence risks of antibiotics in development

Several new antibiotics target multidrug-resistant pathogens, yet resistance is still evaluated mainly by drug-susceptibility, leaving consequences for bacterial pathogenicity poorly understood. Here, we develop a framework integrating resistance evolution, genomic surveillance and host-pathogen phenotyping to classify antibiotics by resistance potential and pathogenic consequences. Applying this framework to Klebsiella pneumoniae identified functionally distinct antibiotic candidates associated with elevated virulence risk. Resistance evolution rapidly increased virulence through clinically-relevant mutations, without direct selection for pathogenicity. Despite distinct genetic routes, resistance converged on cell-envelope rewiring. A single resistance mutation increased epithelial adhesion, intracellular colonization, macrophage immune-evasion, and tissue persistence in murine infection models, transforming K. pneumoniae into a more invasive and cytotoxic pathogen. Risk-profile analysis revealed partial decoupling of resistance and pathogenicity, with some low-resistance antibiotics yielding highly-virulent populations. These findings establish resistance-driven virulence as an underappreciated translational hazard and call for incorporating host-pathogen interactions into resistance surveillance and preclinical antibiotic development.

microbiology↗

bioRxiv2026

Hemoperfusion of pigs with a carbon-cellulose cartridge: a pilot study revealing a new animal model of extended anaphylactic shock

To investigate the immune mechanisms underlying extracorporeal circulation-associated anaphylactoid reactions, we inserted externally perfused cartridges into the venous circulation of pigs, including a cellulose-coated activated-charcoal adsorbent (Adsorba(R) 300C), a polysulfone hollow-fiber membrane hemofilter, and polypropylene hollow-fiber-based heart-lung machine gas-exchange oxygenators. Blood was circulated using a roller pump, and the animals were monitored for systemic and pulmonary arterial pressures (SAP, PAP) changes, blood levels of complement C3a, thromboxane B2, and hemoglobin, blood cell counts and hematocrit. None of the cartridges caused major changes in these endpoints except the Adsorba(R) 300C, which displayed a fulminant anaphylactoid reaction characterized by profound hypotension, maximal pulmonary hypertension, hemoconcentration, thrombocytopenia and a surge of C3a and thromboxane B2, i.e., hallmarks of complement activation-related pseudoallergy. Within 15 min, the reaction advanced to profound hemodynamic collapse, which was managed with norepinephrine and cardiopulmonary resuscitation. After brief rebound hypertension, shock recurred despite repeated rounds of resuscitation until death. Considering that major adverse reactions with overlapping symptoms have been reported in humans subjected to hemoperfusion with the same cartridge, this porcine model provides clinically relevant insights into the mechanisms of extracorporeal circulation-induced anaphylactoid responses. Furthermore, the Adsorba(R) 300C-induced physiological changes along the immune-cardiopulmonary axis represents a new animal model for irreversible cardiovascular collapse escalating into shock.

immunology↗