Salmonella in Wastewater: Identification, Antibiotic Resistance and the Impact on the Marine Environment

Many coastal cities around the world discharge their wastewaters into the marine environment. These wastewaters contain a high variety of pathogenic microorganisms that would have a role in the contamination of this ecosystem and may have potential risks for public health and environment. Using an environmental approach, we investigate the presence of Salmonella in wastewater treatment plants and its presence after the treatment in its receiving marine environment. In this environmental approach, we provide information about the inefficiency of wastewater treatment to remove Salmonella, especially that wastewater is considered as a good tank of high diversity of Salmonella serotypes. The identified Salmonella serotypes in the receiving marine environment almost coincide with those identified in wastewater. This characterization of Salmonella strains from wastewater and marine environment involves the direct impact of municipal wastewater discharges on this environment. Antibiotic susceptibility tests reveal generally the presence of multiresistant Salmonella strains in wastewater, which usually end up in the marine environment and may have a significant risk on the public health

Multinational outbreak of travel-related Salmonella Chester infections in Europe, summers 2014 and 2015

Between 2014 and 2015, the European Centre for Disease Prevention and Control was informed of an increase in numbers of Salmonella enterica serotype Chester cases with travel to Morocco occurring in six European countries. Epidemiological and microbiological investigations were conducted. In addition to gathering information on the characteristics of cases from the different countries in 2014, the epidemiological investigation comprised a matched case-case study involving French patients with salmonellosis who travelled to Morocco that year. A univariate conditional logistic regression was performed to quantify associations. The microbiological study included a whole genome sequencing (WGS) analysis of clinical and non-human isolates of S. Chester of varied place and year of isolation. A total of 162 cases, mostly from France, followed by Belgium, the Netherlands, Spain, Denmark and Sweden were reported, including 86 (53%) women. The median age per country ranged from 3 to 38 years. Cases of S. Chester were more likely to have eaten in a restaurant and visited the coast of Morocco. The results of WGS showed five multilocus sequence types (ST), with 96 of 153 isolates analysed clustering into a tight group that corresponded to a novel ST, ST1954. Of these 96 isolates, 46 (48%) were derived from food or patients returning from Morocco and carried two types of plasmids containing either qnrS1 or qnrB19 genes. This European-wide outbreak associated with travel to Morocco was likely a multi-source outbreak with several food vehicles contaminated by multidrug-resistant S. Chester strains.S