Salmonella outbreaks

Maki DG (2009) Coming to grips with food borne infection - peanut butter, peppers and nationwide salmonella outbreaks. N Engl 1 Med 360 949-953... 

FDA was also very slow in responding to the problem of Salmonella-contaminated eggs. In 1999, FDA announced an Egg Safety Action Plan, and it spent the next five years drafting proposed regulations. After FDA completed the final rule in July 2008, OIRA held it up for the remainder of the Bush Administration. One consequence of the unwarranted delay was a massive Salmonella outbreak in August 2010 that sickened more than 1,200 people and resulted in a recall of more than one-half billion eggs. ... 

National Research Council, National Academy of Sciences, Ensuring Safe Food from Production to Consumption 2 (1998) Dennis G. Maki, Coming to Grips with Food-home Infection—Peanut Butter, Peppers, and Nationwide Salmonella Outbreaks, 360 New Eng. J. Med. 949 (2009) Ben Worthen, Weak Links in the Food (Supply) Chain, WSJ, June 24, 2008, at B5. 

Big Producer in Iowa Have Sickened at Least 1,200, WP, August 20, 2010, at A3 William Neuman, Egg Recall Expanded After Salmonella Outbreak, NYT, August 18, 2010, at Ai. 

Different strains of a number of bacterial species can be distinguished by their sensitivity to a collection of phages. Bacteria which can be typed in this way include Stop/ , aureus and Salmonella typhi. The particular strain ol say, Staph, aureus responsible for an outbreak of infection is characterized by the pattern of its sensitivity to a standard set of phages and then possible sources of infection are examined for the presence of that same phage type of Staph, aureus. 

The Centers for Disease Control (CDC) in the USA has estimated that Campylobacter and Salmonella are the top two bacterial foodbome pathogens as they are responsible for a total of 2 and 1.3 million foodbome infections every year (Mead et al., 1999). Most of the cases of infection with Campylobacter and Salmonella appear to be due to eggs and poultry, but a significant number of cases are related to beef products (CDC, 2005 Jay, 2000). EHEC does not cause as many infections as the top two pathogens (approximately 100,000 in the USA), but EHEC is frequently linked to outbreaks of diarrhea caused by the consumption of contaminated ground beef (Mead et al., 1999, Rangel et al., 2005). Infections caused by EHEC are the major microbial public health concern related to ruminant food products. 

Experiments with gaseous acetic acid have been performed for disinfection of seeds intended for the production of bean sprouts (Delaquis et al., 1999). Salmonella typhimurium and E. coli 0157 H7 were eradicated from the surface of mung bean seeds and it was reported that the seed germination loss was not too large. The seeds have often been the suspected source of contamination in sprout-associated outbreaks and sanitation methods that do not interfere with the germination of the seeds are appreciated. Other volatile chemical treatments have been tested for lethality to Salmonella spp. on alfalfa seeds and sprouts with varying results both on the efficacy of the disinfectant and its effect on sensory qualities (Weissinger et al., 2001). 

Aavitsland, P. and Nygard, K. (2004) Outbreak of Salmonella Thompson Infections. MSIS - Norwegian Surveillance System for Communicable Diseases. 

Anonymous (2002) Multistate outbreaks of Salmonella serotype Poona infections associated with eating cantaloupe from Mexico - United States and Canada, 2000-2002 . MMWR Morbidity and Mortality Weekly Reports, 51, 1044—1047. 

Cummings, K., Barrett, E., Mohle-Boetani, J.C., Brooks, J.T., Farrar, J., Hunt, T., Fiore, A., Komatsu, K., Werner, S.B. and Slutsker, L. (2001) A multistate outbreak of Salmonella enterica serotype Baildon associated with domestic raw tomatoes . Emerging Infectious Diseases, 7, 1046-1048. 

Mahon, B.E., Ponka, A., Hall, W.N., Komatsu, K., Dietrich, S.E., Siitonen, A., Cage, G., Hayes, P.S., Lambert-Fair, M.-A., Bean, N.H., Griffin, P.M. and Slutsker, L. (1997) An international outbreak of Salmonella infections caused by alfalfa sprouts grown from contaminated seeds . Journal of Infectious Diseases, 175, 876-882. 

In the more recent Chicago outbreak of Salmonellosis, which has been attributed to milk contaminated with a tetracycline-resistant strain of Salmonella typhimurium. there were two deaths verified as resulting from infections with the resistant strain of Salmonel la in 16 284 confirmed cases. If one pools these cases with those cited in the NRDC petition then the incidence of mortality (0.09%) is similar or than that of persons affected by antibiotic-sensitive Salmone1 la (0.21%) also cited by NRDC. Thus the similarity of risks of human infections with resistant and sensitive strains of SaImone 11a agrees with research data obtained in controlled experiments (Smith 15). 

For 38 outbreaks of confirmed mode or source (Table II), multiply resistant salmonella were involved in 33% of the community based outbreaks, 40% of the nosocomial, and 75% of the outbreaks involving both community and hospital. In addition, it has been estimated that each culture-documented case among human beings may represent as many as 100 undocumented cases (10). Agency participation for these cases was made at the request of the local health officials and therefore the survey was not random. However, the resistant strains displayed a fatality rate 21 times that of antibiotic sensitive strains. O Brien et al. (10) found that characterization of plasmid DNA from antibiotic resistant salmonella suggests extensive commingling of human and animal bacteria. 

The outbreak of Salmonella foodborne illness in Illinois in April 1985 was attributed to a tetracycline-resistant strain of Salmonella typhimurium. It evidently had no connection with feeding antibiotics in livestock. The resistant strain was of lower virulence than the average sensitive strain. 

The most serious association of antibiotics with salmonellosis was the 1965 outbreak in England of phage type 29 Salmonella typhimurium, resistant to tetracyclines. Six human deaths were attributed to this epidemic. It was traced to "shotgun" treatment of young calves with antibiotics followed by wide dispersal of the calves ( ). Although this epidemic did not involve the use of livestock feeds containing antibiotics, the seriousness of the outbreak led to an inquiry in the UK and a report by the Swann Committee, 1969, into this use. The report of the committee called for a stop to the use of certain common antibiotics in animal feeds in the United Kingdom. 

Salmonella are a frequent cause of foodborne illness, commonly termed "food poisoning," going back long before the use of antibiotics. Salmonellosis is of unusual interest and importance to inhabitants of Chicago because of the outbreak starting in March of 1985, caused by a resistant strain of Salmonella typhimurium. 

The outbreaks described are confined to those investigated by CDC at the request of state health departments and therefore "are not a random sample of all Salmonella oubreaks." However, it is of interest to compare the number of affected persons, 281 per year in the outbreaks studied, with the annual production of 4.2 billion pounds of hamburger in the US, 1982 and 1983. Much of this beef was produced with the aid of antibiotics. 

Holmberg s mortality rate of 0.2% for sensitive Salmonella would have produced 28 deaths in the Illinois outbreak of 14,000 cases. His mortality rate of 4.2% for resistant Salmonella would have led to 588 deaths in the Illinois outbreak, 1985. Clearly the resistant strain in the Illinois outbreak was less virulent than the average sensitive strain. Clearly, we can breathe more freely about antibiotics in livestock feeds, in spite of the "media blitz."... 

There has been a rapid rise in foodborne illness outbreaks linked to fresh produce (Fig. 4.1). The pathogens of main concern are Salmonella and E. coli 0157 H7 although, in principle, a diverse range of pathogenic microbes can contaminate fresh produce at any point in the chain. 

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