Differential Gene Expression of Three Mastitis-CausingEscherichia coliStrains Grown under Planktonic, Swimming, and Swarming Culture Conditions.
Bacterial motility is thought to play an important role in virulence. We have previously shown that proficient bacterial swimming and swarmingin vitrois correlated with the persistent intramammary infection phenotype observed in cattle. However, little is known about the gene regulation differences important for different motility phenotypes inEscherichia coli. In this work, threeE. colistrains that cause persistent bovine mastitis infections were grown in three media that promote different types of motility (planktonic, swimming, and swarming). Using whole-transcriptome RNA sequencing, we identified a total of 935 genes (~21% of the total genome) that were differentially expressed in comparisons of the various motility-promoting conditions. We found that approximately 7% of the differentially expressed genes were associated with iron regulation. We show that motility assays using iron or iron chelators confirmed the importance of iron regulation to the observed motility phenotypes. Because of the observation thatE. colistrains that cause persistent infections are more motile, we contend that better understanding of the genes that are differentially expressed due to the type of motility will yield important information about how bacteria can become established within a host. Elucidating the mechanisms that regulate bacterial motility may provide new approaches in the development of intervention strategies as well as facilitate the discovery of novel diagnostics and therapeutics.IMPORTANCEBacteria can exhibit various types of motility. It is known that different types of motilities can be associated with virulence. In this work, we compare gene expression levels in bacteria that were grown under conditions that promoted three different types ofE. colimotility. Better understanding of the mechanisms of how bacteria can cause an infection is an important first step to better diagnostics and therapeutics.
Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
John D
JD
Lippolis
Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Brian W
BW
Brunelle
Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Timothy A
TA
Reinhardt
Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Randy E
RE
Sacco
Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Tyler C
0000-0001-6779-7649
TC
Thacker
Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Torey P
TP
Looft
Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Ames, Iowa, USA.
Thomas A
TA
Casey
motility; pathogenesis; virulence