Progress 09/01/08 to 08/31/12
Outputs
OUTPUTS: The aim of this longitudinal study was to determine the dynamics of Salmonella in 30 conventional and 8 ABF cohorts at farm, slaughter and in their environment. Overall, a total of 2889 fecal and 2122 environmental samples were collected at farm. In addition, 1363 slaughter and 205 lairage and truck samples each were collected at slaughter. The overall prevalence of Salmonella in conventional and ABF pigs was 4.0% (n=66) and 0.2% (n=2), respectively. At the environment level, 11.8% (n=156) of conventional and 0.6% (n=5) ABF samples tested positive. Salmonella was isolated from 8.3% (conventional) and 5.5% (ABF) slaughter samples. In this study we identified 25 different serotypes among pigs and their environment. In the conventional system, S. Typhimurium (33.7%) was predominant among pig and their environment at farm and slaughter, followed by S. Infantis (16.4%), S.Derby (11.4%), S. Anatum (9.1%) and S. Ouakam (7.8%). In the ABF system, S. Infantis (42.8%) was the predominant serotype followed by S. Anatum (17.8%) and S. Inverness (7.7%). In addition, our study highlights the identification of S. Rissen in pigs and environment, which is rarely found in the US. The isolates were tested as per the CLSI recommended protocol against a panel of 15 antimicrobials. Isolates from conventional pigs were showed highest frequency of resistance to tetracycline (82%) followed by sulfisoxazole (48%), and ampicillin (17%). Whereas isolates from conventional environment showed highest frequency of resistance to tetracycline (88%) followed by sulfisoxazole (49%). ABF isolates from pigs and environment both showed highest frequency of resistance to tetracycline (23%). Multi drug resistant (MDR) (resistance to ≥ 3 antimicrobials) Salmonella were detected in 23% (n=257) of the isolates. Salmonella were characterized for their antimicrobial resistance profile, resistance genes, class I integrons. We detected blaTEM, blaPSE, cmlA, strA, strB, aadA1, aadA2, tetG and blaCMY-2 resistance genes by PCR. Genotypic relationships among Salmonella isolated from the pigs and their environment were detected by Pulsed Field Gel Electrophoresis (PFGE). PARTICIPANTS: Dr. Morgan Morrow: He is a swine extension veterinarian in the Department of Animal Science at NCSU. His primary role was to talk to the swine companies and producers and get them to agree to participate in this USDA project. Dr. Morgan Scott: He is an epidemiologist and his primary role has been in helping with the study design, conduct and oversight, as well as analysis and reporting of these studies as we progress in this project. Dr. Wondwossen Gebreyes: His role in the project is to genotype the Salmonella isolates in years two and three. At this stage, Dr. Gebreyes has provided us input with sample collection and technical information. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This study highlights the prevalence of antimicrobial resistant Salmonella from the conventional and ABF systems at farm and slaughter. The phenotypic and genotypic results of our study indicate that the environment plays an important role in transmission of antimicrobial resistant Salmonella to the conventional and ABF pigs at different stages of production. The prevalence of AR Salmonella in ABF pigs in the absence of selection pressure is concerning.
Publications
- Keelara, S., Gebreyes, W. A., Morrow, W. A., Scott, H. M. Correa, M., and Thakur, S. (2012). Role of environment in the persistence of antimicrobial resistant Salmonella in antimicrobial free (ABF) and conventional pigs at farm and slaughter. Conference of Research Workers in Animal Diseases (CRWAD). December 2-4, Chicago, Illinois.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: The aim of this longitudinal study was to determine the dynamics of Salmonella in 30 conventional and 8 ABF pigs at farms and slaughter and in their environment. Overall, a total of 2889 fecal and 2122 environmental samples were collected at farm. In addition, 1363 slaughter and 205 lairage and truck samples each were collected at slaughter. The overall prevalence of Salmonella in conventional and ABF pigs was 4.7% (n=78) and 0.4% (n=5), respectively. At the environment level, 12% (n=159) of conventional and 0.75% (n=6) ABF samples tested positive. Salmonella was isolated from 8% (conventional) and 6% (ABF) slaughter samples. The isolates were tested as per the CLSI recommended protocol against a panel of 15 antimicrobials. Isolates from conventional pigs were showed highest frequency of resistance to tetracycline (83%) followed by sulfisoxazole (52%), streptomycin (26%) and ampicillin (13%). Whereas isolates from conventional environment showed highest frequency of resistance to tetracycline (78%) followed by sulfisoxazole (32%). ABF isolates from pig and environment showed highest frequency of resistance to tetracycline (29%). Salmonella was characterized for their antimicrobial resistance profile, resistance genes, class I integrons. We detected blaTEM, blaPSE, cmlA, strA, strB, aadA1, aadA2, tetG and blaCMY-2 resistance genes by PCR. Genotypic relationships among Salmonella isolated from the pigs and their environment were detected by Pulsed Field Gel Electrophoresis (PFGE). PARTICIPANTS: 1. Dr. Morgan Morrow: He is a swine extension veterinarian in the Department of Animal Science at NCSU. His primary role was to talk to the swine companies and producers and get them to agree to participate in this USDA project. 2. Dr. Morgan Scott: He is an epidemiologist and his primary role has been in helping with the study design, conduct and oversight, as well as analysis and reporting of these studies as we progress in this project. 3. Dr. Wondwossen Gebreyes: His role in the project is to genotype the Salmonella isolates in years two and three. At this stage, Dr. Gebreyes has provided us input with sample collection and technical information. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This study highlights the prevalence of antimicrobial resistant Salmonella from the conventional and ABF at farm and slaughter. The phenotypic and genotypic results of our study indicate that the environment plays an important role in transmission of antimicrobial Salmonella to the conventional and ABF pigs at different stages of production.
Publications
- Keelara, S., Zou, M., Pierce, H., Whitsell, A., Susick, E., and Thakur, S. (2011). Prevalence, molecular characterization and genotypic analysis of Campylobacter and Salmonella from commercial poultry farms. Sigma Xi Annual Meeting and International research Conference. November 10-13, Raleigh, North Carolina.
- Veerappa, S. K., and Thakur, S. (2011). Genotypic and molecular characterization of multidrug resistant (MDR) Salmonella Typhimurium of swine and human origin. Annual CVM Research Forum, Raleigh, North Carolina.
- Veerappa, S. K., and Thakur, S. (2010). Molecular characterization and Genotypic analysis of Multidrug Resistant (MDR) Salmonella Typhimurium of swine and human origin. Sigma Xi Symposium on Food Safety and Security: Science and Policy, November 11-13, Raleigh, North Carolina.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: The aim of this longitudinal study was to determine the dynamics of Salmonella in conventional and ABF pigs at 10 different farms and slaughter and in their environment. Overall, a total of 2672 fecal and 1942 environmental samples were collected at farm. In addition, 1026 slaughter and 175 lairage and truck samples each were collected at slaughter. The overall prevalence of Salmonella in conventional and ABF pigs was 4% (n=63) and 0.5% (n=5), respectively. At the environment level, 11% (n=141) of conventional and 0.7% (5) ABF samples tested positive. Salmonella was isolated from 8% (conventional) and 7% (ABF) slaughter samples. The isolates were tested as per the CLSI recommended protocol against a panel of 15 antimicrobials and the highest frequency of resistance was detected to tetracycline in pigs and environment. Salmonella was characterized for their antimicrobial resistance profile, resistance genes, class I integrons. We detected blaTEM, blaPSE, cmlA, strA, strB, aadA1, aadA2, tetG and blaCMY-2 resistance genes by PCR. Genotypic relationships among Salmonella isolated from the pigs and their environment were detected by Pulsed Field Gel Electrophoresis (PFGE). PARTICIPANTS: Dr. Morgan Morrow: He is a swine extension veterinarian in the Department of Animal Science at NCSU. His primary role was to talk to the swine companies and producers and get them to agree to participate in this USDA project. Dr. Morgan Scott: He is an epidemiologist and his primary role has been in helping with the study design, conduct and oversight, as well as analysis and reporting of these studies as we progress in this project. Dr. Wondwossen Gebreyes: His role in the project is to genotype the Salmonella isolates in years two and three. At this stage, Dr. Gebreyes has provided us input with sample collection and technical information. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This study highlights the prevalence of antimicrobial resistant Salmonella from the conventional and ABF at farm and slaughter. The phenotypic and genotypic results of our study indicate that the environment plays an important role in transmission of antimicrobial Salmonella to the conventional and ABF pigs at different stages of production.
Publications
- Veerappa, S. K., and Thakur, S. 2010. Environmental role in the transmission of multidrug resistant (MDR) Salmonella to conventional pigs at different stage of production at farm and slaughter. Conference of Research Workers in Animal Diseases (CRWAD). December 5-7, Chicago, Illinois.
- Thakur, S., Correa, M., Morrow, W. M., and Scott, H. M. 2010. Molecular Epidemiology of Salmonella in Conventional and Antimicrobial Free Swine Production (ABF) Systems. USDA National Research Initiative Principal Investigator Annual Meeting and Institute of Food Technologists Annual Meeting. July, Chicago, Illinois.
- Veerappa., S. K., Morrow, W. E., Gebreyes, W. A., Correa, M., Scott, H. M., and Thakur, S. 2010. Role of environment in transmission of antimicrobial resistant salmonella in antimicrobial free (ABF) pigs at farm and slaughter. 110th General ASM Meeting in San Diego, California.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: Sample Collection at commercial and antimicrobial free (ABF) swine production systems in North Carolina Sample collection is currently underway in North Carolina. Every pig selected in this study will be sampled five times as it moves from farrowing to the finishing farms. The pigs will again be sampled at the slaughter plant at post-evisceration and post-chill stages. In addition, environmental samples will be collected at every stage at farm and slaughter. Multiple Salmonella isolates (up to three) will be collected from every positive sample to determine the diversity of the pathogen within individual pigs. To date, we have completed sample collection at five ABF farms including the farm and slaughter stages. In addition, two commercial farms are currently being sampled in their final sampling stages at the finishing farms. Questionnaires and other related information at farm and slaughter is being collected from individual farm owners and currently being coded and analyzed. Salmonella prevalence among pigs and carcasses in North Carolina: Two pigs out of 706 pigs in ABF farm (0.28%) and four pigs out of 197 pigs in Commercial farm (1.93%) were positive. Salmonella prevalence at slaughter level is 15.6% (35 positive out of 223 samples). At post chill we isolated the pathogen from five carcass of pigs reared in the ABF production system. A total of 183 isolates were isolated from both ABF and Commercial farms (farm: 83 and slaughter: 100). Antimicrobial susceptibility testing of Salmonella isolates: We are in the process of testing the Salmonella isolates for their antimicrobial susceptibility profile. The isolates were tested as per the CLSI recommended protocol. The isolates were tested for their susceptibility against 15 antimicrobials namely: Amikacin, ampicilin, amoxicillin/clavulanic acid, ceftriaxone, chloramphenicol, ciprofloxacin, trimethoprim/sulfamethaxazole, cefoxitin, gentamycin, kanamycin, nalidixic acid, sulfisoxazole, streptomycin, tetracycline and ceftiofur. So far we have tested 55 isolates out of 183 isolates. Salmonella isolates from slaughter exhibited maximum frequency of resistance against tetracycline (69.09%, n=38) where as only two out of 16 from farm were resistant to tetracycline, streptomycin and kanamycin. PARTICIPANTS: Individuals 1. Dr. Morgan Morrow: He is a swine extension veterinarian in the Department of Animal Science at NCSU. His primary role is to talk to the swine companies and producers and get them to agree to participate in this USDA project. All the farms that we have enrolled and sampled in this project so far have been arranged through the extension work done by him. Dr. Morrow will also be responsible for the extension and education aspects of this proposal as the project enters in years two and three. 2. Dr. Morgan Scott: He is an epidemiologist and his primary role has been in helping with the study design, conduct and oversight, as well as analysis and reporting of these studies as we progress in this project. The specific tasks that he will contribute to in the proposed research relate to initial design and implementation of the study, oversight of conduct and compliance and sample size issues, descriptive and analytical approaches for data and reporting. He will assist with presenting and discussing the findings at key scientific meetings. So far, we have utilized his expertise in designing the questionnaires. 3. Dr. Wondwossen Gebreyes: His role in the project is to genotype the Salmonella isolates in years two and three. At this stage, Dr. Gebreyes has provided us input with sample collection and technical information. 4. Deena Bermudez: Deena has been hired through this USDA grant to work as a field technician. She has been responsible for scheduling, arranging and packing for the farm trip. She has also aided in sample processing and Salmonella isolation in this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Impact This study highlights the prevalence of antimicrobial resistant Salmonella from both the commercial and the ABF at farm and slaughter. Even though only a few pigs were positive at the farm level, a higher number of carcass swabs came out positive at the slaughter plant indicating that the slaughter plant environment is possibly playing an important role in Salmonella transmission.
Publications
- No publications reported this period
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