Herd prevalence of Salmonella enterica infections in Danish slaughter pigs determined by microbiological testing

Abstract As a part of a nationwide programme to survey and control salmonella in pig herds, a microbiological survey of 1363 pig herds was performed in Denmark. A total of 13 468 slaughter pigs were examined at slaughter by culture of 5 g of caecal contents. Overall, 30 different serotypes of Salmonella enterica were isolated from 832 pigs (6.2%). The predominant serotype was S. Typhimurium, comprising 536 (64.4%) of the isolates. Four hundred and forty-eight isolates of S. Typhimurium were examined by phage typing, resulting in detection of 17 different phage types (definitive types, DT) with DT12 being the most frequent (49.1%). Salmonella enterica was found in 302 herds (22.2%), S. Typhimurium was found in 61.1% of these. 279 (23.1%) large herds (producing more than 2600 slaughter pigs per year) were found to be salmonella positive compared with 23 (14.7 %) small herds (annual production of 500 to 550 slaughter pigs). Practical constraints in the study design did not allow for a firm conclusion on the interplay among herd size, geographical location and occurrence of salmonella. In 284 of 302 infected herds (94.0%) only one serotype was detected. Infections with two different serovars were seen in 18 herds (6.0%).

[1]  M. Popoff.  Antigenic formulas of the Salmonella serovars , 1997 .

[2]  P. Guiñee,et al.  Experimental salmonella infections in pigs. , 2010, Zentralblatt fur Veterinarmedizin. Reihe B. Journal of veterinary medicine. Series B.

[3]  A. Rambach.  New plate medium for facilitated differentiation of Salmonella spp. from Proteus spp. and other enteric bacteria , 1990, Applied and environmental microbiology.

[4]  D. Baggesen,et al.  The serological response to Salmonella serovars typhimurium and infantis in experimentally infected pigs. The time course followed with an indirect anti-LPS ELISA and bacteriological examinations. , 1995, Veterinary microbiology.

[5]  Preben Willeberg,et al.  Veterinary epidemiology: Principles and methods: by S.W. Martin, A.H. Meek and P. Willeberg. Iowa State University Press, Ames, IA 50010, 1987, 343 pp., price US$30.95 (plus US$1.50 postage/handling for first copy; US$0.75 for additional copies), ISBN 0-8138-1856-7 , 1989 .

[6]  P. Guiñee,et al.  Salmonella in pigs on farms feeding pellets and on farms feeding meal. , 1974, Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene. Erste Abteilung Originale. Reihe A: Medizinische Mikrobiologie und Parasitologie.

[7]  Mohamed Shoukri,et al.  Evaluating the health status of herds based on tests applied to individuals , 1992 .

[8]  A. Pospischil,et al.  Distribution of persistent Salmonella typhimurium infection in internal organs of swine. , 1989, American journal of veterinary research.

[9]  S. T. Jørgensen.  Prevalence and molecular epidemiology of antibiotic-resistant Salmonella typhimurium and Salmonella dublin in Danish cattle. , 2009, Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology.

[10]  P. Fedorka-Cray,et al.  Alternate routes of invasion may affect pathogenesis of Salmonella typhimurium in swine , 1995, Infection and immunity.

[11]  T. Humphrey,et al.  Poultry meat as a source of human salmonellosis in England and Wales , 1988, Epidemiology and Infection.

[12]  R. Rose,et al.  Populations of Salmonella typhimurium in internal organs of experimentally infected carrier swine. , 1992, American journal of veterinary research.

[13]  Y. Tanaka,et al.  Salmonella carriers in swine. , 1973, Nihon juigaku zasshi. The Japanese journal of veterinary science.

[14]  E. S. Anderson,et al.  Bacteriophage-typing designations of Salmonella typhimurium , 1977, Journal of Hygiene.

[15]  H. Maguire,et al.  A large outbreak of human salmonellosis traced to a local pig farm , 1993, Epidemiology and Infection.

[16]  R. Rose,et al.  Experimental establishment of persistent infection in swine with a zoonotic strain of Salmonella newport. , 1991, American journal of veterinary research.

[17]  R. Harvey,et al.  Salmonella surveillance with reference to pigs – Cardiff abattoir, 1968–1975 , 1977, Journal of Hygiene.

[18]  Martin Currier,et al.  Salmonella in Swine at Slaughter: Incidence and Serovar Distribution at Different Seasons. , 1986, Journal of food protection.

[19]  D. O'boyle,et al.  The isolation of Salmonella from jejunal and caecal lymph nodes of slaughtered animals. , 1980, Australian veterinary journal.

[20]  H C Wegener,et al.  Phage Types of Salmonella enterica ssp. enterica serovar Typhimurium Isolated from Production Animals and Humans i Denmark , 1994, Acta Veterinaria Scandinavica.

[21]  Alvin D. Wiggins,et al.  Cut-off points for aggreate herd testing in the presence of disease clustering and correlation of test errors , 1994 .

[22]  H C Wegener,et al.  Salmonella Typhimurium phage types from human salmonellosis in Denmark 1988–1993 , 1994, APMIS : acta pathologica, microbiologica, et immunologica Scandinavica.

[23]  A. Donner,et al.  The statistical analysis of multiple binary measurements. , 1988, Journal of clinical epidemiology.

[24]  J. Cowden,et al.  Case-control study of infections with Salmonella enteritidis phage type 4 in England. , 1989, BMJ.

[25]  H. Layton,et al.  Influence of antibiotic-supplemented feed on occurrence and persistence of Salmonella typhimurium in experimentally infected swine. , 1976, American journal of veterinary research.

[26]  B. R. Callow.  A new phage-typing scheme for Salmonella typhi-murium , 1959, Journal of Hygiene.