EVALUATE THE DISSEMINATION OF SAMONELLA IN THE ENVIRONMENT FOLLOWING LAND APPLICAITON OF SWINE MANURE

• Sponsoring Institution: Cooperating Schools of Veterinary Medicine
• Project Status: COMPLETE
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 1001703
• Project Start Date: Sep 30, 2013
• Project End Date: Jul 1, 2015
• Program Code: [(N/A)]- (N/A)

Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695

Performing Department
Population Health and Pathobiology

Non Technical Summary
There is tremendous pressure on the US pork industry to ban the prophylactic use of antimicrobials in feed due to generation of antimicrobial resistant (AR) bacterial strains. An important concern is the dissemination of AR Salmonella in the environment after swine manure application. We propose to conduct a study on 15 commercial swine farms, which will provide important information on the dissemination of AR Salmonella in the environment following land application of swine manure. The study will be conducted in leading pork producing states in the US including North Carolina, Iowa and Indiana. We will identify swine farms that have a Salmonella positive status in the three states to conduct the study. Salmonella prevalence will be compared before and after days 0 (2 hours), 7, 14 and 28 post manure application on specific land locations on every site.

Animal Health Component

(N/A)

Research Effort Categories

Basic

100%

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
104	0199	1103	100%

Knowledge Area
104 - Protect Soil from Harmful Effects of Natural Elements;

Subject Of Investigation
0199 - Soil and land, general;

Field Of Science
1103 - Other microbiology;

Keywords

swine

salmonella

environment

Goals / Objectives
We have designed this field based research study that will be conducted on commercial swine farm locations to determine the dissemination of AR Salmonella on application of swine manure in the environment in accordance with their waste management program. The proposed research study will provide information on the occurrence and distribution of AR Salmonella, its antimicrobial resistance phenotypes and genotypes in swine manure which is directly applied in the field. The objectives are: 1) To determine the dissemination of AR Salmonella on land following manure application from commercial swine farms, 2) To characterize and compare the Salmonella isolated from different sources on farm and environment using phenotypic and genotypic approaches, and; 3) To analyze whether the different farm variables like soil type and antimicrobial use on farm impact the dissemination of AR Salmonella from the farm to the environment. The proposed field based research study will be conducted on actual commercial swine farms in North Carolina, Iowa and Indiana who have agreed to cooperate on this important project. The baseline data generated in this study will help us to apply for future multi institutional and multistate longitudinal studies.

Project Methods
The swine farm samples will consist of the following sample type (quantity; amount): a) lagoon (n=10; 25 ml including two each from the center and the four corners) OR b) swine manure pit slurry (n=10; 25 ml). The lagoon or manure pit samples will be collected only once on day 0 at the start of sampling. The environment samples will consist of soil samples following the scheme described in the previous section. We have identified farms with deep sandy soils (i.e. greater than 30 inches to a sandy clay loam horizon) and with soils that have a sandy surface horizon over a sandy clay loam horizon 10 to 12 inches below the surface. Samples will be placed in whirl pack bags (50 gm) for transport from the farm premises. Soil samples will be collected from the surface as described previously (Boes et al., 2005). We will collect five soil samples weighing 100 gm each and 10 inches deep from every grid on the land. Samples will be placed in whirl pack bags for transport from the farm premises. All the samples will be stored in an ice cooler at 4ºC and transported to the laboratory for further analysis. Daily maximum and minimum temperatures will be recorded at every sample collection day besides measuring other environmental conditions as indicated in the questionnaire. Samples collected in North Carolina (Dr. Thakur lab), Iowa (Dr. McKean Lab) and Indiana (Dr. Rostagno lab) will be processed in the respective laboratories. All the labs will use the same protocols for Salmonella isolation. Salmonella isolated in Indiana and Iowa will subsequently be shipped to North Carolina to Dr. Thakur`s lab for further phenotypic and genotypic characterization.

Progress 09/30/13 to 07/01/15

Outputs
Target Audience:Pork industry, National Pork Board Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Final report submitted to the sponsor, National Pork Board. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? There is tremendous pressure on the US pork industry to ban the prophylactic and growth promotion use of antimicrobials in feed due to generation of antimicrobial resistant (AMR) bacterial strains. An important concern is the dissemination of AMR Salmonella in the environment after swine manure application. The main objective of this study was to determine the potential role of lagoons and manure pits in the transmission of AMR Salmonella in in the environment following land application of swine manure on commercial swine farms in Iowa (n=7) and North Carolina (n=6). In Iowa the manure is stored in pits and applied using an injection system while manure in NC is stored in lagoons and applied directly on the soil using a spray method. Salmonella prevalence was compared on these conventional swine farms at different time points including day 0 (before and after manure application) and subsequently on days 7, 14 and 28 post manure application on specific land locations at every site. The samples consisted of lagoon/manure pit and soil on day 0 while only soil samples were collected on the following sampling time points. Overall, we collected a total of 1,200 soil samples (IA=700; NC=500) and 50 lagoon and 70 manure pit samples from NC and IA, respectively. Overall Salmonella prevalence was 13.33% (176/1320) while the prevalence in soil and lagoon were 10.92% and 37.5%, respectively. The Salmonella prevalence in North Carolina (28.18%) was significantly higher than in Iowa (2.73%) (p < 0.001). We detected a significant decrease in prevalence of Salmonella from the marked areas as we moved from Day0 to Day21. We identified 12 serotypes, however, it is important to note that no serotype found in one state was detected from the other highlighting serotype associated based on geographic region. For example, we detected Anatum (7.39%), Litchffield (3.98%), and Infantis (0.57%) in IA, while Altona (7.95%), Derby (3.98%), Johannesburg (3.98%), Mbandaka (1.70%), Muenster (9.09%), Rissen (0.57%), Typhimurium var5- (20.45%), Uganda (2.27%), and Worthington (5.68%) in NC. A total of 80.47% of the Salmonella isolates were multidrug resistant (MDR; resistance to three or more antimicrobials) with the most frequent AMR against Streptomycin (82.81%), sulfisoxazole (73.44%), and kanamycin (61.72%). PFGE genotyping revealed genotype relatedness among Salmonella recovered from lagoon and soil at multiple time points with relatively close geographic proximity and serotypes. Our study highlights Salmonella transmission in the environment in commercial swine farms is dependent on the type of manure storage and its application method. Finally, the rapid decline in the prevalence of Salmonella in soil samples on subsequent collection days (Days 7, 14, 21) clearly indicates the inability of this pathogen to survive in the environment for longer durations.

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