Screening for virulence gene markers in clinical a. hydrophila isolates from southern chennai (India)

The opportunistic and ubiquitous Aeromonas spp., is receiving growing importance since its implication in a wide spectrum of human diseases few decades ago. The enteric pathogen A.hydorphila, is the most commonly associated pathogen with acute diarrhoea, with a similar prevalence world-wide. While the host susceptibility to the disease depends on various risk factors that includes food and water source contaminations, the myriad of virulence factors- Haemolyin, exotoxins etc., craft the complex pathogenicity of A.hydrophila and thus, extensive studies on this bacteria is imperative, especially in developing nations were hygiene measure controls are often neglected. In the present case-control study, PCR was employed to screen two extensively investigated A.hydrophila virulence determinants-aerA and hlyA genes- in clinical bacterial isolates to ascertain the bacterial strain’s pathogenicity in acute diarrhoea from the chosen geographical region. 107 (20.89%) out of 512 acute diarrhoeal patients screened harboured the enteric pathogen, A. hydrophila, while the asymptomatic control subjects (n=200) showed no faecal carriage of this micro-organism. Consistent with previous reports the clinical A.hydrophila isolates screened carried the aerA+, hlyA+, aerA+ hlyA+-virulent genotypes (albeit at varying frequencies) ascertaining the role of the two toxins –Haemolysin (HlyA) and Aerolysin (AerA)-in influencing the pathogenesis of acute diarrhoea in Southern Chennai (India).