Antibiotic resistance in Prevotella species isolated from patients with cystic fibrosis

Laura J Sherrard, Kathryn A Graham, Stef J McGrath, Leanne McIlreavey, Joseph Hatch, Marianne S Muhlebach, Matthew C Wolfgang, Deirdre F Gilpin, J Stuart Elborn, Thamarai Schneiders, Michael M Tunney

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24 Citations (Scopus)

Abstract

Objectives

Chlamydia pneumoniae, an obligate intracellular bacterium, has been associated with asthma and the induction of immunoglobulin E (IgE) responses. Whereas tetracyclines have anti-chlamydial activity, their effect on human IgE responses to C. pneumoniae has not been studied.

Methods

Peripheral blood mononuclear cells (PBMCs) from serum IgE+ allergic asthmatic subjects (n = 11) and healthy controls (n = 12) were infected with C. pneumoniae and cultured for 12 days with or without doxycycline (0.01–1.0 mg/L). IgE, interferon (IFN)-γ and interleukin (IL)-4 levels in supernatants were determined on days 1–12 post-infection, and C. pneumoniae DNA copy numbers in PBMC culture were measured on day 2 (quantitative PCR).

Results

C. pneumoniae-infected PBMCs from allergic asthmatic individuals had increased levels of IgE in supernatants compared with uninfected PBMCs (520% on day 10 post-infection, P = 0.008). IgE levels in PBMC cultures from controls were undetectable (<0.3 ng/mL). Increases in C. pneumoniae-induced IgE in asthmatics correlated with those of C. pneumoniae-induced IL-4 (r = 0.98; P < 0.001), but not with IFN-γ. The addition of doxycycline (1.0 mg/L) to the culture strongly suppressed the production of IgE (>70%, P = 0.04) and IL-4 (75%, P = 0.018), but not IFN-γ. The suppressive effect on IL-4 production remained significant even at concentrations of doxycycline that were subinhibitory (0.01 mg/L) for C. pneumoniae. In both asthmatic participants and controls, no significant effect of doxycycline on DNA copy numbers of C. pneumoniae was observed.

Conclusions

Doxycycline suppressed the C. pneumoniae-induced production of IgE and IL-4, but not IFN-γ, in PBMCs from IgE+ allergic asthmatic subjects. These findings resulted from the immunomodulatory anti-allergic properties of tetracyclines.

Original languageEnglish
Pages (from-to)2369-2374
JournalJournal of Antimicrobial Chemotherapy
Volume68
Issue number10
Early online date21 May 2013
DOIs
Publication statusPublished - Oct 2013

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