ABSTRACTLeptospira interrogansis a global zoonotic pathogen and is the causative agent of leptospirosis, an endemic disease of humans and animals worldwide. There is limited understanding of leptospiral pathogenesis; therefore, further elucidation of the mechanisms involved would aid in vaccine development and the prevention of infection. HtpG (high-temperatureproteinG) is the bacterial homolog to the highly conserved molecular chaperone Hsp90 and is important in the stress responses of many bacteria. The specific role of HtpG, especially in bacterial pathogenesis, remains largely unknown. Through the use of anL. interroganshtpGtransposon insertion mutant, this study demonstrates thatL. interrogansHtpG is essential for virulence in the hamster model of acute leptospirosis. Complementation of thehtpGmutant completely restored virulence. Surprisingly, thehtpGmutant did not appear to show sensitivity to heat or oxidative stress, phenotypes common inhtpGmutants in other bacterial species. Furthermore, the mutant did not show increased sensitivity to serum complement, reduced survival within macrophages, or altered protein or lipopolysaccharide expression. The underlying cause for attenuation thus remains unknown, but HtpG is a novel leptospiral virulence factor and one of only a very small number identified to date.
Nudix-type RNA pyrophosphohydrolase provides homeostasis of virulence factor pyocyanin and functions as a global regulator inPseudomonas aeruginosa
