Dataset Information

H(2)O(2), which causes macrophage-related stress, triggers induction of expression of virulence-associated plasmid determinants in Rhodococcus equi.

ABSTRACT: The response of the intracellular pathogen Rhodococcus equi to H(2)O(2) treatment, a situation potentially encountered after the oxidative burst of alveolar macrophages, was analyzed. Compared to other bacteria, including Deinococcus radiodurans, R. equi showed exceptionally high resistance to this stress. A proteomic approach showed that four polypeptides present in the wild-type strain (85F) are missing in the plasmid-cured strain 85F(P-), and by using a DNA macroarray, we identified two plasmid-encoded vap genes, vapA and vapG, whose expression was highly induced by H(2)O(2) treatment. Whereas the transcript size of vapA was compatible with a monocistronic mRNA, the transcript of vapG was considerably longer. Rapid amplification of cDNA ends PCRs showed that the transcriptional start sites of the two operons were 69 and 269 nucleotides (nt) upstream of the start codon, respectively. Analysis of these leader sequences revealed the presence of a small open reading frame named podG, which encodes a sequence of 55 amino acids preceded by a putative ribosome binding site sequence in the vapG transcript. Taking this result into account, the untranslated leader of the podG/vapG operon is 87 nt. Alignment of this sequence with the leader sequences of vapA and vapD, genes previously shown to be induced by acid, revealed significant homologies. Since our results showed that vapA, vapD, and vapG are genes highly induced by macrophage-related stresses, their gene products may, within the Vap protein family, play a dominant role inside these phagocytic cells and may be the most promising candidates for vaccination strategies.

SUBMITTER: Benoit S

PROVIDER: S-EPMC128077 | biostudies-literature | 2002 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

H(2)O(2), which causes macrophage-related stress, triggers induction of expression of virulence-associated plasmid determinants in Rhodococcus equi.

Benoit Stephanie S Benachour Abdellah A Taouji Said S Auffray Yanick Y Hartke Axel A

Infection and immunity 20020701 7

The response of the intracellular pathogen Rhodococcus equi to H(2)O(2) treatment, a situation potentially encountered after the oxidative burst of alveolar macrophages, was analyzed. Compared to other bacteria, including Deinococcus radiodurans, R. equi showed exceptionally high resistance to this stress. A proteomic approach showed that four polypeptides present in the wild-type strain (85F) are missing in the plasmid-cured strain 85F(P-), and by using a DNA macroarray, we identified two plasm ...[more]

PMID: 12065520

Similar Datasets

Project description:Conjugation is one of the main mechanisms involved in the spread and maintenance of antibiotic resistance in bacterial populations. We recently showed that the emerging macrolide resistance in the soilborne equine and zoonotic pathogen Rhodococcus equi is conferred by the erm(46) gene carried on the 87-kb conjugative plasmid pRErm46. Here, we investigated the conjugal transferability of pRErm46 to 14 representative bacteria likely encountered by R. equi in the environmental habitat. In vitro mating experiments demonstrated conjugation to different members of the genus Rhodococcus as well as to Nocardia and Arthrobacter spp. at frequencies ranging from ∼10-2 to 10-6 pRErm46 transfer was also observed in mating experiments in soil and horse manure, albeit at a low frequency and after prolonged incubation at 22 to 30°C (environmental temperatures), not 37°C. All transconjugants were able to transfer pRErm46 back to R. equi Conjugation could not be detected with Mycobacterium or Corynebacterium spp. or several members of the more distant phylum Firmicutes such as Enterococcus, Streptococcus, or Staphylococcus Thus, the pRErm46 host range appears to span several actinobacterial orders with certain host restriction within the Corynebacteriales All bacterial species that acquired pRErm46 expressed increased macrolide resistance with no significant deleterious impact on fitness, except in the case of Rhodococcus rhodnii Our results indicate that actinobacterial members of the environmental microbiota can both acquire and transmit the R. equi pRErm46 plasmid and thus potentially contribute to the maintenance and spread of erm(46)-mediated macrolide resistance in equine farms.IMPORTANCE This study demonstrates the efficient horizontal transfer of the Rhodococcus equi conjugative plasmid pRErm46, recently identified as the cause of the emerging macrolide resistance among equine isolates of this pathogen, to and from different environmental Actinobacteria, including a variety of rhodococci as well as Nocardia and Arthrobacter spp. The reported data support the notion that environmental microbiotas may act as reservoirs for the endemic maintenance of antimicrobial resistance in an antibiotic pressurized farm habitat.

Dataset Information

H(2)O(2), which causes macrophage-related stress, triggers induction of expression of virulence-associated plasmid determinants in Rhodococcus equi.

Publications

H(2)O(2), which causes macrophage-related stress, triggers induction of expression of virulence-associated plasmid determinants in Rhodococcus equi.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets