Characterization of Stress and Innate Immunity Resistance of Wild-Type and Δp66 Borrelia burgdorferi

Abstract

is a causative agent of Lyme disease, the most common arthropod-borne disease in the United States. evades host immune defenses to establish a persistent, disseminated infection. Previous work showed that P66-deficient (Δ) is cleared quickly after inoculation in mice. We demonstrate that the Δ strain is rapidly cleared from the skin inoculation site prior to dissemination. The rapid clearance of Δ bacteria is not due to inherent defects in multiple properties that might affect infectivity: bacterial outer membrane integrity, motility, chemotactic response, or nutrient acquisition. This led us to the hypothesis that P66 has a role in mouse cathelicidin-related antimicrobial peptide (mCRAMP; a major skin antimicrobial peptide) and/or neutrophil evasion. Neither wild-type (WT) nor Δ was susceptible to mCRAMP. To examine the role of neutrophil evasion, we administered neutrophil-depleting antibody anti-Ly6G (1A8) to C3H/HeN mice and subsequently monitored the course of infection. Δ mutants were unable to establish infection in neutrophil-depleted mice, suggesting that the important role of P66 during early infection is through another mechanism. Neutrophil depletion did not affect WT bacterial burdens in the skin (inoculation site), ear, heart, or tibiotarsal joint at early time points postinoculation. This was unexpected given that prior studies demonstrated neutrophils phagocytose and kill These data, together with our previous work, suggest that despite the ability of host innate defenses to kill , individual innate immune mechanisms have limited contributions to controlling early infection in the laboratory model used.

The Lon‐2 protease of Borrelia burgdorferi is critical for infection in the mammalian host

“…In order to delineate the molecular mechanisms underlying the critical role of Lon‐2 in mammalian infection, we examined the tolerance of B. burgdorferi to high‐salt conditions by growing spirochetes in BSK‐II medium with varying concentrations of NaCl. Based on a previous study (Curtis et al, ), normal BSK‐II contains ~ 120 mM NaCl. In our experiments, we added NaCl to BSK‐II to a final concentration of 150‐, 200‐, or 300‐mM and growth of B. burgdorferi in these modified media were determined.…”

“…The resistance of B. burgdorferi to osmotic stress was determined as previously described (Curtis et al, ). In brief, a starter culture of B. burgdorferi was cultivated in BSK‐II until late logarithmic phase.…”

Biofilm/Persister/Stationary Phase Bacteria Cause More Severe Disease Than Log Phase Bacteria – I BiofilmBorrelia burgdorferiNot Only Display More Tolerance to Lyme Antibiotics But Also Cause More Severe Pathology In a Mouse Arthritis Model: Implications for Understanding Persistence, PTLDS and Treatment Failure

“…It 83 is generally assumed that all bacteria are created equal and are equally able to cause disease in a host. Most 84 studies use log phase bacteria for infections and pay more attention to the number of bacteria used for infection 85 rather than the quality of the bacterial inocula [19][20][21][22]. Our findings that biofilm/persister inocula produce a 86 more severe disease than log phase bacteria call attention to quality of the bacteria inocula used for infection 87…”

BBB07 contributes to, but is not essential for, Borrelia burgdorferi infection in mice

“…burgdorferi WT, T184-5, or T184-7, or with phosphate-buffered saline (PBS) supplemented with 0.2 % heat-inactivated C3H/HeN serum as the vehicle control. Mice were euthanized at 1 week or 4 weeks following inoculation, and tissue samples or organs were cultured in BSK II supplemented with 50 µg ml −1 rifampin, 20 µg ml −1 phosphomycin and 2.5 µg ml −1 amphotericin B [6–8] to assess the presence of live Borrelia . Cultures were followed for up to 8 weeks post-inoculation before being declared negative.…”

“…Bacterial burdens in a variety of tissues were measured by quantitative PCR (qPCR) using primers targeting recA ( B. burgdorferi ) and mouse (nidogen) DNA [6–11]. The quantitative PCR (qPCR) data were analysed for statistical significance using Kruskal–Wallis followed by Dunn’s multiple comparisons test in GraphPad Prism.…”