YfbA, a Yersinia pestis Regulator Required for Colonization and Biofilm Formation in the Gut of Cat Fleas

For transmission to new hosts,Yersinia pestis , the causative agent of plague, replicates as biofilm in the foregut of fleas that feed on plague-infected animals or humans.Y. pestis biofilm formation has been studied in the rat flea; however, little is known about the cat flea, a species that may bridge zoonotic and anthroponotic plague cycles. Here, we show thatY. pestis infects and replicates as a biofilm in the foregut of cat fleas in a manner requiringhmsFR , two determinants for extracellular biofilm matrix. Examining a library of transposon insertion mutants, we identified the LysR-type transcriptional regulator YfbA, which is essential forY. pestis colonization and biofilm formation in cat fleas.