Shewanella oneidensis employs both β-lactam resistance and tolerance controlled by the PghKR system.

Shewanella oneidensis uses a single regulatory system, PghKR, to control both β-lactam resistance and tolerance, enabling survival under antibiotic stress.

• Why it matters: Understanding how bacteria simultaneously employ resistance and tolerance is crucial because it complicates treatment strategies and may lead to antibiotic failure, especially with combination therapies.
• What they did: The study analyzed a β-lactamase-deficient S. oneidensis strain, demonstrating that PghKR regulates tolerance through the protein SO2195, which maintains cell envelope integrity under cell wall stress.
• The result: This regulatory pathway allows bacteria to dynamically balance resistance and tolerance, suggesting that targeting both mechanisms is essential for effective antimicrobial strategies.