Deletion of theaceEgene (encoding a component of pyruvate dehydrogenase) attenuatesSalmonella entericaserovar Enteritidis

Abstract

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major food-borne pathogen. From a transposon insertion mutant library created previously using S. Enteritidis 10/02, one of the mutants was identified to have a 50% lethal dose (LD(50) ) at least 100 times that of the parental strain in young chicks, with an attenuation in a poorly studied gene encoding a component of pyruvate dehydrogenase, namely the aceE gene. Evaluation of the in vitro virulence characteristics of the ΔaceE∷kan mutant revealed that it was less able to invade epithelial cells, less resistant to reactive oxygen intermediate, less able to survive within a chicken macrophage cell line and had a retarded growth rate compared with the parental strain. Young chicks vaccinated with 2 × 10(9) CFU of the ΔaceE∷kan mutant were protected from the subsequent challenge of the parental strain, with the mutant colonized in the liver and spleen in a shorter time than the group infected with the parental strain. In addition, compared with the parental strain, the ΔaceE∷kan mutant did not cause persistent eggshell contamination of vaccinated hens.

Disruption of the pdhB Pyruvate Dehydrogenase Gene Affects Colony Morphology, In Vitro Growth and Cell Invasiveness of Mycoplasma agalactiae

“…Even though PDH mutants have slower in vitro growth phenotypes, they have often been detected in STM screens, and PDH has been suggested to play important roles in the pathogenicity of other bacterial pathogens [ 44 , 45 ]. Recently, PDHB of M .…”

Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection

“…Interestingly, only 6-29 (pdhB) showed slower log-phase growth (40). Nevertheless, this mutant also was included in the current in vivo study, because pyruvate dehydrogenase mutants in other bacteria also are known to exhibit in vitro slow-growth phenotypes, yet they have been used in STM screens and are accepted as playing important roles in the pathogenicity of these bacteria (41,42). An in vitro growth competition assay performed with the pool of 14 selected mutants used as inocula for confirmatory screening did not reveal any growth retardation (P Ͼ 0.05) for any of the 7 mutants that showed 100% absence in vivo.…”

Pyruvate dehydrogenase complex—enzyme 2, a new target for Listeria spp. detection identified using combined phage display technologies

“…In another study, PDC-E1 of Salmonella enterica subsp. enterica serovar Enteritidis was described as a virulence factor, once mutants with deletions or without the gene showed to be less capable of causing important symptoms of the disease 67 . Characteristics such as slower growth and increased membrane fluidity also occur in PDC-deficient Staphylococcus aureus, indicating a structural impact of the enzyme 68 .…”