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

Abstract

BackgroundThis 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.ResultsSalmonella 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% harboured plasmids. Salmonella Typhimurium strains were isolated harbouring at least one of the following virulence genes: spvC, invA or 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.ConclusionsThe results obtained demonstrated that Salmonella spp. have been found in sewage sludge, thus it is essential to set measures to mitigate human health risks when it is intended to be applied on agricultural soils.

Eastern China coastal mudflats: Salt‐soil amendment with sewage sludge

“…Previous studies mainly focused on risk of pathogens contamination from applying sludge in farmlands (Gondim-Porto et al, 2016;Krzyzanowski et al, 2014;Peyton et al, 2016)…”

Salmonella in Indian ready-to-cook poultry: antibiotic resistance and molecular characterization

“…24 Whereas another study reported the presence of invA gene in Salmonella is not universal, as during their study out of 35 tested strains of Salmonella, 33 harboured sseL as well as invA virulence genes, however two strains (Salmonella Molade and Salmonella München), did not harbour the invA virulence gene. 25 Seventy percent of the Salmonella isolates carried the class 1 integron. Class 1 integron specific PCR detected double amplicons (1 kb and 1.2 kb) in 53.9% isolates (Supplementary Figure S1).…”

Avaliação da presença de elementos potencialmente tóxicos decorrentes da produção informal e domiciliar de joias e bijuterias na rede de esgoto sanitário de Limeira-SP

“…The disposal of PTEs in the sludge in regions where electroplating occurs is proven and some studies have discussed different methods of toxic metal removal from electroplating wastewater and sludge to avoid the leaching of toxic elements Sousa et al, 2009;Peng and Tian, 2010;Wuana and Okieimen, 2011;Chou et al, 2011;Zhuang et al, 2012;Huang et al, 2013). In Brazil, one of the alternatives used for final sludge disposal is the composting for agricultural (Krzyzanowski et al, 2014;. The increase in PTEs concentration in the soil and agricultural plants, after compost application, has been observed (Gonçalves et al, 2014;Grotto et al, 2015;Nascimento et al, 2015).…”

“…O lodo de esgoto pode ser usado para recuperação energética, como fonte de extração de compostos, como por exemplo, a recuperação de fósforo ou pode ser tratado e usado em terra como fertilizante e condicionador de solo (Fijalkowski et al, 2017). A aplicação agrícola ou disposição em aterros são as opções de menor custo e comumente utilizadas no mundo (Cai et al, 2007;Krzyzanowski et al, 2014Krzyzanowski et al, , 2016Grotto et al, 2015). Considerando que as constituições dos lodos de esgoto podem apresentar tanto patógenos como substâncias tóxicas e os elementos podem se acumular ou mobilizar no solo, sua aplicação na agricultura pode representar um risco ambiental que deve ser monitorado (Cai et al, 2007;Chen et al, 2008;Grotto et al, 2015;Fijalkowski et al, 2017).…”