A national outbreak of multi-resistant Salmonella enterica serovar Typhimurium definitive phage type (DT) 104 associated with consumption of lettuce

Abstract

Between 1 August and 15 September 2000, 361 cases of Salmonella enterica serotype Typhimurium definitive phage type (DT) 104, resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, spectinomycin and tetracycline (R-type ACSSuSpT), were identified in England and Wales residents. Molecular typing of 258 isolates of S. Typhimurium DT104 R-type ACSSuSpT showed that, although isolates were indistinguishable by pulsed-field gel electrophoresis, 67% (174/258) were characterized by a particular plasmid profile. A statistically significant association between illness and consumption of lettuce away from home was demonstrated (OR = 7.28; 95% CI=2.25-23.57; P=0.0006) in an unmatched case-control study. Environmental investigations revealed that a number of food outlets implicated in the outbreak had common suppliers of salad vegetables. No implicated foods were available for microbiological testing. An environmental audit of three farms that might have supplied salad vegetables to the implicated outlets did not reveal any unsafe agricultural practices. The complexity of the food supply chain and the lack of identifying markers on salad stuffs made tracking salad vegetables back to their origin extremely difficult in most instances. This has implications for public health since food hazard warnings and product withdrawal are contingent on accurate identification of the suspect product.

Distribution and Characterization of Salmonella enterica Isolates from Irrigation Ponds in the Southeastern United States

“…Montevideo and Newport have been identified in several multistate outbreaks associated with fresh produce (4,6,37,49), while Hadar was more associated with meat or poultry (50,51). Strains with genetic similarity to serotypes Saintpaul, Braenderup, Thompson, and Javiana have also been recovered in produce-related outbreaks (6,42,(52)(53)(54), and Javiana is the most commonly reported serotype for salmonellosis in Florida (Carina Blackmore, Florida Department of Health, personal communication). Recently, Newport, Cerro, and Thompson were reported as the most common serovars of isolates from produce-growing regions of New York State, while Saphra, Newport, and S. enterica subsp.…”

Investigation of Routes of Salmonella Contamination Via Soils and the Use of Mulch for Contamination Control during Lettuce Cultivation

“…For instance, outbreaks of Salmonella Typhimurium and Escherichia coli O157:H7 in Europe and USA were linked to leafy vegetables such as lettuce and spinach (Horby et al, 2003;Heaton and Jones, 2008;Parker et al, 2012). Epidemic survey also showed a high possibility of leafy vegetables infected with E. coli O157:H7 at the farm (Parker et al, 2012;Cooley et al, 2007).…”

Escherichia coli Common Pilus (ECP) Targets Arabinosyl Residues in Plant Cell Walls to Mediate Adhesion to Fresh Produce Plants

“…Several bacterial pathogens have been involved in different foodborne outbreaks, including pathogenic Escherichia coli and Salmonella enterica (5)(6)(7)(8)(9)(10).…”