International Journal of Microbiology and Immunology Research Vol. 3(6), pp. 076-083, October 2015 ISSN 2327-7769 ©2015 Academe Research Journals

Full Length Research Paper

Incidence and antibiotic resistant profiles of pathogenic Salmonella spp. from different environmental and food samples

Sureka Indrajith¹, Baskaran Athmanathan¹, Dinesh Kumar Subbaraj¹, Velmurugan Meganathan¹, Jennifer Emelda Edward Arockiaraj¹, Jesuraj Edison Woodrowwilson² and Sathiyamurthy Karuppannan¹*

¹Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli-620024, Tamil Nadu, India.

²Department of Zoology, PMT College, Melaneelithanallur, Tirunelveli-627953, Tamil Nadu, India.

*Corresponding author. E-mail: ksathiyamurthy@yahoo.com.

Accepted 1 September, 2015

Abstract

Salmonella bacteria cause one of the leading foodborne infections resulting in gastroenteritis and salmonellosis in people of all ages. They also cause severe invasive disease in infants, elderly persons and immuno-compromised persons. Here, we report the isolation, identification and antibiotic resistant pattern of Salmonella enterica isolated from water and sediment samples collected from coastal and river sources as well as poultry and seafood samples from retail shops in Tamil Nadu, India. Sampling was done at different intervals. All the samples were primarily enriched with Selenite F broth and plated on Xylose Lysine Deoxycholate (XLD), Deoxycholate Citrate Agar (DCA) and Brilliant Green Agar (BGA). Out of the 121 samples screened for the presence of S. enterica, 97 (80%) samples were found positive. From the 503 suspected S. enterica isolates screened, only 402 (80%) strains were confirmed as S. enterica through phenotypic characters. However, molecular approaches showed that 371 (74%) isolates were S. enterica. Fresh water sample (113), poultry meat (90) and seafood sample (71) had the highest number of S. enterica contamination followed by fresh water sediment (53), coastal water sample (46) and coastal sediment (29). Of all the strains, 371 strains (92%) possessed the gene InvA which helped in confirming the virulence factor through PCR molecular screening. Among these 23 (6%) isolates which exhibited haemolytic activity, antimicrobial susceptibility pattern was tested by the standard disc diffusion technique. A high level of resistance among all the strains was observed against Rifampicin, Vancomycin and Ampicillin. However, 63 (16%) isolates showed multidrug resistance against more than three antibiotics. Multidrug resistant and frequent isolation of S. enterica from various sources of samples are matters of serious concern as they pose threat to public health.

Key words: Salmonella enterica, food borne infection, InvA gene, haemolytic activity, multi drug resistance.