Quantification and characterization of Salmonella spp. isolates in sewage sludge with potential usage in agriculture

• Grant number: 14/50731-4
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: December 01, 2014
• End date: May 31, 2015
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Maria Tereza Pepe Razzolini
• Grantee: Maria Tereza Pepe Razzolini
• Host Institution: Faculdade de Saúde Pública (FSP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This study aims to scrutinize Salmonella spp. and its serotypes in sewage sludge samples from wastewater treatment plants, and assesses the presence of virulence genes and antibiotics resistant to the profile. Samples (n=54) were collected and analyzed in accordance with the EPA Method 1682/2006. For positive serological reaction, 40 strains were selected for PCR analyses and detection of spvC, invA and sseL virulence genes, plasmid presence and resistance to antibiotics. Salmonella spp. was detected in 38.9% of the samples collected «0.006473 to 12.19 MPN/gTS). The most prevalent serotype was Salmonella infantis. All Salmonella spp. (n=35) presented at least one of the three virulence genes mentioned above and 40% harbored plasmids. Salmonella Typhimurium strains were isolated harboring at least one of the following virulence genes: spvC, invA ar sseL. Four Salmonella spp. isolates were resistant to tetracycline; three were resistant to trimethoprim-sulfamethoxazole, and one isolate was resistant to ciprofloxacin. Two Salmonella spp. strains presented multi resistance to antimicrobial agents. (AU)