Bartonella quintana Deploys Host and Vector Temperature-Specific Transcriptomes

Abstract

The bacterial pathogen Bartonella quintana is passed between humans by body lice. B. quintana has adapted to both the human host and body louse vector niches, producing persistent infection with high titer bacterial loads in both the host (up to 105 colony-forming units [CFU]/ml) and vector (more than 108 CFU/ml). Using a novel custom microarray platform, we analyzed bacterial transcription at temperatures corresponding to the host (37°C) and vector (28°C), to probe for temperature-specific and growth phase-specific transcriptomes. We observed that transcription of 7% (93 genes) of the B. quintana genome is modified in response to change in growth phase, and that 5% (68 genes) of the genome is temperature-responsive. Among these transcriptional changes in response to temperature shift and growth phase was the induction of known B. quintana virulence genes and several previously unannotated genes. Hemin binding proteins, secretion systems, response regulators, and genes for invasion and cell attachment were prominent among the differentially-regulated B. quintana genes. This study represents the first analysis of global transcriptional responses by B. quintana. In addition, the in vivo experiments provide novel insight into the B. quintana transcriptional program within the body louse environment. These data and approaches will facilitate study of the adaptation mechanisms employed by Bartonella during the transition between human host and arthropod vector.

A family of genus‐specific RNAs in tandem with DNA‐binding proteins control expression of the badA major virulence factor gene in Bartonella henselae

“…Several regulatory proteins of Bartonella have been proposed to play a role in this response (Battisti et al., ; Quebatte et al., , ; Roden et al., ). The adaptive response is also thought to be controlled by an alternate sigma factor RpoE of the general stress response system found in both B. quintana (Abromaitis & Koehler, ; Abromaitis et al., ) and B. henselae (Tu et al., ). Genes in the B. henselae general stress response regulon include the hemin‐binding proteins and the badA adhesin (Tu et al., ).…”

“…Recently, a novel alternate sigma factor activation mechanism has been shown to induce a general stress response in B. quintana (Abromaitis & Koehler, ). This general stress response was shown to regulate genes in response to temperature that corresponds to a shift from the vector to humans and vice versa (Abromaitis et al., ). This same general stress response has been described in B. henselae and shown to play a role in regulating badA (Tu, Lima, Bandeali, & Anderson, ).…”

Assessment of vector-host-pathogen relationships using data mining and machine learning

“…Moreover, there is evidence to suggest that the process of adaptation to particular arthropod vectors can influence microbial pathogenicity in vertebrates. The latter may occur either through microbial genome degradation as a result of the adaptation process and/or as a result of changes in microbial transcriptomes driven by the arthropod host [10] , [11] , [12] .…”

Iron Starvation Conditions Upregulate Ehrlichia ruminantium Type IV Secretion System, tr1 Transcription Factor and map1 Genes Family through the Master Regulatory Protein ErxR

“…This is particularly true for bacterial pathogens whose expression of virulence factors is tightly regulated in response to host and non-host environments (Hyytiäinen et al, 2003 ). Thus, the regulation of T4SS in response to host cues enables the efficient use of bacterial resources and facilitates colonization, leading to full infection (Abromaitis et al, 2013 ). One such environmental signal is iron, which is an essential cofactor in various enzymatic reactions like respiration, DNA replication, oxygen transport, response to oxidative stress, but can be toxic at excessive intracellular concentrations (Andrews et al, 2003 ).…”