Screening of Aeromonads as associated pathogens from Non-Tuberculous Mycobacterial infections in the aquaculture industry, West Bengal, India

The disease termed as ‘Ulcerative disease' or ‘Erythematous disease' is found in fishes and fish handlers and is caused by a group of waterborne Mycobacterium spp. called non-tuberculous mycobacteria (NTM). The wounds are frequently invaded by secondary pathogens like Aeromonas spp. which is ubiquitous in nature. NTMs are free-living bacterium inhabiting water bodies, causing skin lesions in fish and fish handlers. The secondary invaders are natural inhabitants and are found in excess due to anthropogenic pollution in aquatic environments affecting the fishes and human subjects as low-level latent infectants in wounds caused by NTM. This study highlights the various aspects mycobacteriosis followed by secondary infection and hemorrhagic septicemia caused by Aeromonas spp. in the state of West Bengal (WB), India. NTM and Aeromonas spp. samples were examined from different districts of WB. In the case of Fish handlers, NTM infection as well as Aeromonas spp. infected wounds were highly significant (correlation coefficient (ρ) 0.859, p<0.01). Ulcerative fishes predominant with NTMs were significantly higher in the total samples studied (correlation coefficient 0.718, p<0.01) than the fishes infected with both Aeromonas spp. and NTM (ρ 0.188, p< 0.5). Systematic reporting of mycobacteriosis and associated pathogens studied here will help to improvise the drug regimes used in culture-based fisheries systems.