External biosecurity protocols, aimed at preventing the introduction of new pathogens to the farm... more External biosecurity protocols, aimed at preventing the introduction of new pathogens to the farm environment, are becoming increasingly important in the swine industry. Although assessments at the individual farm level occur regularly, efforts to cluster swine herds into meaningful biosecurity groups and to summarize this information at the regional level are relatively infrequent. The objectives of this study were: (i) to summarize external biosecurity practices on sow farms in southern Ontario; (ii) to cluster these farms into discrete biosecurity groups and to describe their characteristics, the variables of importance in differentiating between these groups, and their geographic distribution; and (iii) to identify significant predictors of biosecurity group membership. Data were collected using the Production Animal Disease Risk Assessment Program's Survey for the Breeding Herd. A subset of variables pertaining to external biosecurity practices was selected for two-step cluster analysis, which resulted in 3 discrete biosecurity groups. These groups were named by the authors as: (i) high biosecurity herds that were open with respect to replacement animals, (ii) high biosecurity herds that were closed with respect to replacement animals, and (iii) low biosecurity herds. Variables pertaining to trucking practices and the source of replacement animals were the most important in differentiating between these groups. Multinomial logistic regression provided insight into which demographic and neighborhood variables serve as significant predictors of biosecurity group membership (p<0.05). Variables in the final regression model include: herd density within a 4.8 km radius, number of sows on the premises, and site production type. The odds of belonging to the high biosecurity group that was open with respect to replacement animals, relative to the low biosecurity group, increased 1.001 times for each additional sow (p=0.001). The odds of belonging to the high biosecurity group that was open with respect to replacement animals, relative to the low biosecurity group, were 6.5 times greater for farms that produced genetic animals than for farms that produced commercial animals (p=0.003). The information obtained through this work allows a better understanding of biosecurity in sow herds at the regional level, and the implementation of biosecurity protocols in North American swine herds in general.
PCR or hybridization assays are widely used for the identification and detection of various Esche... more PCR or hybridization assays are widely used for the identification and detection of various Escherichia coli serogroups and serotypes. This study explored this approach for the detection of E. coli O149 in pigs, a dominant serogroup among those associated with porcine post-weaning diarrhea (PWD) worldwide. For this purpose, we sequenced the O antigen (rfb) gene cluster of a representative enterotoxigenic E. coli (ETEC) O149:H10 strain and identified a 2kbp region specific for the O149 rfb gene cluster. This region lacked similarity with sequences in GenBank, except for the rfb gene cluster of the human pathogen Shigella boydii O1 with which it shares 99% sequence identity. Southern blot hybridization with 91 E. coli strains belonging to 62 serogroups confirmed the specificity of the identified region. Restriction analysis of the rfb gene cluster of 38 geographically and chronologically diverse E. coli O149 strains with the endonucleases HindIII, PstI and XhoI demonstrated that this cluster is highly conserved across the serogroup O149. Analysis of the O antigen of a representative O149:H10 ETEC strain by nuclear magnetic resonance confirmed the identity of the O antigen structure in recent and older O149 ETEC strains. Finally, we developed a real-time PCR assay for the detection of E. coli O149 in pig fecal samples by targeting the part of the rfb sequence specific for this serogroup. This method was suitable for a sensitive qualitative detection of O149 E. coli in pig fecal samples after enrichment, but further investigations are needed to find a suitable method for a direct, reproducible and sensitive quantification of O149 E. coli in pig feces.
Methicillin resistant Staphylococcus aureus (MRSA) colonization has recently been identified in p... more Methicillin resistant Staphylococcus aureus (MRSA) colonization has recently been identified in pigs and people that work with pigs, raising concerns about the role of pigs as reservoirs of MRSA for human infection. The objectives of this study were to evaluate the prevalence of ...
External biosecurity protocols, aimed at preventing the introduction of new pathogens to the farm... more External biosecurity protocols, aimed at preventing the introduction of new pathogens to the farm environment, are becoming increasingly important in the swine industry. Although assessments at the individual farm level occur regularly, efforts to cluster swine herds into meaningful biosecurity groups and to summarize this information at the regional level are relatively infrequent. The objectives of this study were: (i) to summarize external biosecurity practices on sow farms in southern Ontario; (ii) to cluster these farms into discrete biosecurity groups and to describe their characteristics, the variables of importance in differentiating between these groups, and their geographic distribution; and (iii) to identify significant predictors of biosecurity group membership. Data were collected using the Production Animal Disease Risk Assessment Program's Survey for the Breeding Herd. A subset of variables pertaining to external biosecurity practices was selected for two-step cluster analysis, which resulted in 3 discrete biosecurity groups. These groups were named by the authors as: (i) high biosecurity herds that were open with respect to replacement animals, (ii) high biosecurity herds that were closed with respect to replacement animals, and (iii) low biosecurity herds. Variables pertaining to trucking practices and the source of replacement animals were the most important in differentiating between these groups. Multinomial logistic regression provided insight into which demographic and neighborhood variables serve as significant predictors of biosecurity group membership (p<0.05). Variables in the final regression model include: herd density within a 4.8 km radius, number of sows on the premises, and site production type. The odds of belonging to the high biosecurity group that was open with respect to replacement animals, relative to the low biosecurity group, increased 1.001 times for each additional sow (p=0.001). The odds of belonging to the high biosecurity group that was open with respect to replacement animals, relative to the low biosecurity group, were 6.5 times greater for farms that produced genetic animals than for farms that produced commercial animals (p=0.003). The information obtained through this work allows a better understanding of biosecurity in sow herds at the regional level, and the implementation of biosecurity protocols in North American swine herds in general.
PCR or hybridization assays are widely used for the identification and detection of various Esche... more PCR or hybridization assays are widely used for the identification and detection of various Escherichia coli serogroups and serotypes. This study explored this approach for the detection of E. coli O149 in pigs, a dominant serogroup among those associated with porcine post-weaning diarrhea (PWD) worldwide. For this purpose, we sequenced the O antigen (rfb) gene cluster of a representative enterotoxigenic E. coli (ETEC) O149:H10 strain and identified a 2kbp region specific for the O149 rfb gene cluster. This region lacked similarity with sequences in GenBank, except for the rfb gene cluster of the human pathogen Shigella boydii O1 with which it shares 99% sequence identity. Southern blot hybridization with 91 E. coli strains belonging to 62 serogroups confirmed the specificity of the identified region. Restriction analysis of the rfb gene cluster of 38 geographically and chronologically diverse E. coli O149 strains with the endonucleases HindIII, PstI and XhoI demonstrated that this cluster is highly conserved across the serogroup O149. Analysis of the O antigen of a representative O149:H10 ETEC strain by nuclear magnetic resonance confirmed the identity of the O antigen structure in recent and older O149 ETEC strains. Finally, we developed a real-time PCR assay for the detection of E. coli O149 in pig fecal samples by targeting the part of the rfb sequence specific for this serogroup. This method was suitable for a sensitive qualitative detection of O149 E. coli in pig fecal samples after enrichment, but further investigations are needed to find a suitable method for a direct, reproducible and sensitive quantification of O149 E. coli in pig feces.
Methicillin resistant Staphylococcus aureus (MRSA) colonization has recently been identified in p... more Methicillin resistant Staphylococcus aureus (MRSA) colonization has recently been identified in pigs and people that work with pigs, raising concerns about the role of pigs as reservoirs of MRSA for human infection. The objectives of this study were to evaluate the prevalence of ...
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