nonO1O139

Non-O1/non-O139 Vibrio cholerae refers to Vibrio cholerae strains that do not belong to the O1 or O139 serogroups. Unlike the epidemic-causing O1 and O139 lineages, most non-O1/non-O139 strains do not carry the cholera toxin gene ctxAB and are not associated with large cholera outbreaks.

Ecology and transmission: These strains are widespread in marine and estuarine environments, especially in warmer months, and can be found in seawater, sediment, and seafood. Human infections commonly follow ingestion of contaminated seafood, particularly raw or undercooked shellfish, or exposure of wounds to seawater or brackish water. Transmission is typically sporadic rather than outbreak-driven.

Clinical manifestations: Many non-O1/non-O139 strains cause mild gastroenteritis with diarrhea and abdominal cramps, but symptoms can range from self-limited illness to more severe diarrhea. In some cases, especially among people with underlying liver disease, diabetes, or immunocompromise, these strains can cause invasive infections such as bacteremia, focal wound infections, or septicemia.

Virulence and diagnosis: Most non-O1/non-O139 strains lack the cholera toxin genes and are less likely to cause epidemic disease. They may possess other virulence determinants, including hemolysins or secretion systems, which contribute to virulence in certain contexts. Diagnosis relies on laboratory culture and serogroup testing to establish non-O1/non-O139 status and to differentiate them from epidemic serogroups; selective media such as TCBS agar are commonly used.

Treatment and management: For gastroenteritis, management emphasizes rehydration and electrolyte replacement; antibiotics are not routinely required but may be used in severe or invasive cases, guided by susceptibility testing. Commonly considered agents include doxycycline, azithromycin, or fluoroquinolones, with therapy tailored to local resistance patterns. Prevention focuses on safe seafood handling and thorough cooking, plus wound care for seawater exposure.