Salmonella enterica Subclinical Infection: Bacteriological, Serological, Pulsed-Field Gel Electrophoresis, and Antimicrobial Resistance Profiles—Longitudinal Study in a Three-Site Farrow-to-Finish Farm

• Published in: Foodborne pathogens and disease Vol. 6; no. 8; pp. 965 - 972
• Main Authors: Vigo, German B, Cappuccio, Javier A, Pineyro, Pablo E, Salve, Angela, Machuca, Mariana A, Quiroga, Maria A, Moredo, Fabiana, Giacoboni, Gabriel, Cancer, Jose L, Caffer, Ines G, Binsztein, Norma, Pichel, Mariana, Perfumo, Carlos J
• Format: Journal Article
• Language: English
• Published: United States 01.10.2009
• Subjects: Aging; Animal Husbandry - methods; animal pathogenic bacteria; Animals; antibiotic resistance; Argentina - epidemiology; bacterial contamination; Bacterial Shedding; bacteriology; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; Drug Resistance, Bacterial - genetics; Electrophoresis, Gel, Pulsed-Field - veterinary; farrowing; feces; Feces - microbiology; Female; finishing; food pathogens; Genetic Variation; immunologic techniques; isolation; Longitudinal Studies; Male; multiple drug resistance; Phylogeny; pulsed-field gel electrophoresis; Rectum - microbiology; Salmonella enterica; Salmonella enterica - classification; Salmonella Infections, Animal - epidemiology; Salmonella Infections, Animal - microbiology; Salmonella Infections, Animal - prevention & control; Salmonella typhimurium; salmonellosis; Seroepidemiologic Studies; serotypes; Serotyping - veterinary; sows; Swine; Swine Diseases - epidemiology; Swine Diseases - microbiology; swine feeding; swine housing; Time Factors; virulence; Argentina
• ISSN: 1535-3141; 1556-7125
• DOI: 10.1089/fpd.2008.0239

The aim of this surveillance was to study both Salmonella spp. shedding patterns and the time course of serological response in farrow-to-finish reared pigs from a subclinically infected farm. Antimicrobial resistance profile, molecular subtyping, and the relationship among the isolates were determined by pulsed-field gel electrophoresis (PFGE). A farrow-to-finish farm of 6000 sows, with a history of Salmonella Typhimurium septicemia, was selected. A longitudinal bacteriological and serological study was conducted in 25 sows before farrowing (M/S1) and in 50 offspring at 21 (M/S2), 35 (M/S3), 65 (M/S4), 86 (M/S5), 128 (M/S6), and 165 (M/S7) days of age. Serum antibodies were tested using Herdcheck Swine Salmonella antibody test kit (Idexx Laboratories, ME). Bacteria were isolated from pooled fecal samples. Suspected isolates were confirmed by conventional biochemical assays, and those identified as Salmonella spp. were serotyped. A variation between seropositive percentages and positive fecal samples was observed. Serologically positive pigs decreased from S1 to S4, and subsequently increased from S4 to S7. The percentages of fecal positive culture increased from M1 to M3, and then declined in M4, increased in M5, and were negative in M6 and M7.