O6 gastroenteritis in a patient with lupus nephritis - a report from coastal Karnataka, South India.

Introduction: O1 strains are responsible for pandemics of cholera and major epidemics in the world. All the remaining non-O1/non-O139 strains are less virulent and are responsible for sporadic cases of gastroenteritis. These non-O1/non-O139 serogroups have more than 200 somatic antigens, and mostly lack cholera toxin and toxin co-regulated pilus encoding genes. Toxigenic and non-toxigenic non-O1/non-O139 have caused several diarrhoeal outbreaks in India and other countries. Acute gastroenteritis is the typical clinical sign and symptom of non-O1/non-O139 infection for both periodical and outbreak cases; in contrast, these are rarely associated with extraintestinal infections.

Case Presentation: Here, we present a case of a 27-year-old female with underlying kidney disease (lupus nephritis) presenting with loose stools, vomiting and fever. O6 was isolated from a faecal sample, which was positive for and the type III secretion system. The present case is, to the best of our knowledge, the first such case to be reported from South India.

Conclusion: The O6 associated with autoimmune disease in the present study demonstrates the role of this pathogen in acute gastroenteritis, and if it is left undiagnosed it can lead to septicaemia and other complications. The pathogenic mechanisms of non-O1/non-O139 are multivariate, virulence factors being naturally present in these strains. Therefore, further epidemiological studies are necessary to determine the virulence factors and their pathogenic mechanisms. Non-O1/non-O139 can undoubtedly be the cause of diarrhoea and it would be important to extend bacteriological identification in this line as well as in all cases of gastroenteritis of unknown aetiology.