The human pathogen Vibrio cholerae has stumped scientists since its discovery 150 years ago. Experts who studied the bacterium were puzzled that the bacterium was unable to grow under anaerobic conditions although it was equipped with active metabolic machinery to breathe nitrate instead of oxygen, conditions that typically exist in the gastrointestinal tract. The common opinion was that the bacteria accumulates the intermediate product nitrite, which inhibits further growth. The research group of Felipe Cava at the Laboratory for Molecular Infection Medicine Sweden has now studied this bacteria under low-oxygen and varied pH-conditions. Together with their colleagues in Boston, U.S., the scientists at Umeå University discovered an elegant pH-dependent metabolic mechanism that permits the pathogen to switch to a resting mode with preserved viability. The strategy provides a competitive advantage against commensal bacteria to better colonize and infect the intestine. The group have published their results in Nature Microbiology.