A study on the prevalence of Aeromonas spp. and its enterotoxin genes in samples of well water, tap water, and bottled water

Research (Published online: 28-10-2015)

14. A study on the prevalence of Aeromonas spp. and its enterotoxin genes in samples of well water, tap water, and bottled water -Hareesh Didugu, Madhavarao Thirtham, Krishnaiah Nelapati, K Kondal Reddy, Baba Saheb Kumbhar, Anusha Poluru and Guruvishnu Pothanaboyina

Veterinary World, 8(10): 1237-1242

   doi: 10.14202/vetworld.2015.1237-1242

Abstract

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Aim: The aim of this work was to study the prevalence of Aeromonas spp. and its enterotoxin genes in various water sources.

Materials and Methods: 125 samples (50 from well water, 50 from tap water, and 25 from bottled water) were collected from various sources in and around Greater Hyderabad Municipal Corporation and examined for the presence of aeromonads by both cultural and polymerase chain reaction (PCR) assay. Alkaline peptone water with ampicillin was used as enrichment. Aeromonas isolation medium and ampicillin dextrin agar were used as selective media. The boiling and snap chilling method was used for DNA extraction. Primers targeted against 16S rRNA, aer, and ast were used to identify aeromonads and its enterotoxins.

Results: 48%, 18%, and 12% of well water, tap water, and bottled water samples were found positive by cultural assay with an overall prevalence of 28.8%. Aeromonads were detected in 32 % (52% in well water, 20% in tap water, and 16% in bottled water) of samples by PCR assay. Aerolysin (aer) gene was noticed in 34.6%, 20%, and 0% of well water, tap water, and bottled water samples, respectively, with an overall prevalence of 27.5%. Thermostable cytotonic enterotoxin (ast) was observed in 37.5% (42.3% in well water, 30% in tap water, and 25% in bottled mineral water) of samples.

Conclusions: Presence of aeromonads and its toxin genes in various sources of water is of public health concern and emphasizes the need for necessary preventive measures to tackle the problem.

Keywords: Aeromonas spp., enterotoxins, polymerase chain reaction, prevalence, water.