Effective characterization of Salmonella Enteritidis by most probable number (MPN) followed by multiplex polymerase chain reaction (PCR) methods

Abstract

Nontyphoidal Salmonella (NTS) is a relevant pathogen involved in gastroenteritis outbreaks worldwide. In this study, we determined the capacity to combine the most probable number (MPN) and multiplex polymerase chain reaction (PCR) methods to characterize the most important Salmonella serotypes in raw sewage. A total of 499 isolates were recovered from 27 raw sewage samples and screened using two previously described multiplex PCR methods. From those, 123 isolates were selected based on PCR banding pattern-identical or similar to Salmonella Enteritidis and Salmonella Typhimurium-and submitted to conventional serotyping. Results showed that both PCR assays correctly serotyped Salmonella Enteritidis, however, they presented ambiguous results for Salmonella Typhimurium identification. These data highlight that MPN and multiplex PCR can be useful methods to describe microbial quality in raw sewage and suggest two new PCR patterns for Salmonella Enteritidis identification.

Antimicrobial profile of non-typhoidal Salmonella isolated from raw sewage in the Metropolitan Region of São Paulo, Brazil

“…The strains were isolated from raw sewage, which was treated by activated sludge and then released into natural rivers. Therefore, it is possible that these pathogens have reached the environment [26,35,41]. While most human Salmonella infections appear to be foodborne, salmonellosis can also be acquired through contaminated drinking water [42,43].…”

“…One-hundred and four (104) non-typhoidal Salmonella enterica subsp. enterica isolates were previously recovered from raw sewage samples in 2013, according to the USEPA 2012 guidelines [26]. For the present study, enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) method [27] was used to assess the genetic similarity amongst the isolates (data not shown) and select 45 non-clonal strains for this study: 25 S.1,4, [5],12:i:-, seven Salmonella Cerro, six Salmonella Enteritidis, four Salmonella Braenderup and three Salmonella Typhimurium.…”

“…In a recent study in Brazil, our group isolated several non-typhoidal Salmonella serovars in sewage sludge [25] and raw sewage samples [26] from the Metropolitan Region of São Paulo. In this study, we investigated the antimicrobial susceptibility profile and the primary AMR genes carried by those strains.…”

Yaygın Salmonella Serovarlarının Moleküler Tekniklerle Tiplendirilmesi

“…Salmonella serotipleri arasında veya özel bir serotip içerisinde ayrım yapmak için tanımlanan PZR-tabanlı metotlar optimize edilmiştir. (1,7,12,18,19,24). PCR-tabanlı metotlar ile direk somatik antijenlerin (10,11,14,21), ve/veya flagellar antijenlerin (4,5,9) tespit edilmesine yönelik çalışmalar da mevcuttur.…”