|Carlson, Steve - COLLEGE OF VET MED,ISU|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 30, 2008
Publication Date: May 12, 2009
Citation: Patton, T.G., Scupham, A.J., Bearson, S.M., Carlson, S.A. 2009. Characterization of Fecal Microbiota from a Salmonella Endemic Cattle Herd as Determined by Oligonucleotide Fingerprinting of rDNA Genes. Veterinary Microbiology. 136(3-4):285-292. Interpretive Summary: Recent outbreaks of food-borne salmonellosis highlight the need for reducing bacterial pathogens in food animals. Intestinal pathogens of livestock serve as direct sources of meat contamination and as indirect sources of fruit and vegetable contamination when manure is used to fertilize crops. Understanding the ecology of bacterial pathogens in the environment and in the animal host is essential for protecting the nation’s food supply. The first step in any ecological study is a complete description of the organisms. In this work, the population of fecal bacteria from cattle was described. An individual cow can host greater than 500 different intestinal bacterial species, and although the majority of bacteria described from 19 different cows belonged to three dominant phyla, very few specific species were detected in more than one animal. One Ruminobacter species was detected only in Salmonella- free cows. Further examination of this species will determine whether its presence is inhibitory to Salmonella colonization of the cattle intestinal tract.
Technical Abstract: The gastrointestinal (GI) tract microbiota is composed of complex communities. For all species examined thus far, culture and molecular analyses show that these communities are highly diverse and individuals harbor unique consortia. These microorganisms are influenced by the diet, host, and environment and play important roles in health and disease of the host. Bovine fecal microbiota has been previously analyzed using both culture and molecular methods. The objective of this work was to extensively analyze the composition of fecal microbiota of cattle using a ribosomal gene array-based approach, oligonucleotide fingerprinting of ribosomal genes (OFRG). The OFRG analysis included 1440 16S genes from 19 fecal samples obtained from a cattle herd with a history of salmonellosis. Identified bacteria belonged to the phyla Firmicutes (53%), Bacteroidetes (17%), and Proteobacteria (17%). Sequence analysis of 16S rDNA gene clones revealed that Spirochaetes were also present in the feces. The majority of Firmicutes present in the feces belonged to the order Clostridiales, which was verified via dot blot analysis. Beta-proteobacteria were determined by real-time PCR to represent 1.5% of the bacterial community. Clones with 16S sequences similar to Ruminobacter amylophilus were unique to samples from Salmonella- negative cattle. This analysis provides basal information on the bacterial composition of cattle feces that can be used to establish a profile of GI inhabitants relevant to animal health and food safety.