Long-term treatment with sub-antimicrobial dose doxycycline has no antibacterial effect on intestinal flora
Authors: Walker, Clay1; Preshaw, Philip M.2; Novak, John3; Hefti, Arthur F.4; Bradshaw, Mark5; Powala, Christopher5
Source: Journal of Clinical Periodontology, Volume 32, Number 11, November 2005 , pp. 1163-1169(7)
Publisher: Blackwell Publishing
Abstract:
Walker C, Preshaw PM, Novak J, Hefti AF, Bradshaw M, Powala C. Long-term treatment with sub-antimicrobial dose doxycycline has no antibacterial effect on intestinal flora. J Clin Periodontol 2005; 32: 1163-1169. doi: 10.1111/j.1600-051X.2005.00840.x. © Blackwell Munksgaard 2005. Abstract Aim: The purpose of this study was to determine if a 9-month regimen of sub-antimicrobial doxycycline (20 mg, bid) had an effect on either the intestinal or the vaginal microflora. Material and Methods: A total of 69 periodontally diseased subjects were randomized to receive drug or placebo control for a 9-month period. Stool specimens and vaginal swabs were collected at baseline and after 3 and 9 months of therapy. Samples were examined for total anaerobic counts, opportunistic pathogens, and doxycycline-resistant (⩾4 μg/ml) bacteria. All isolates that survived sub-culture were identified and their susceptibilities determined to six antibiotics. Analyses were performed to determine if treatment differences were present. Results: The only statistically significant differences (p<0.05) between the two treatment groups occurred in the doxycycline-resistant counts at the baseline sample period for the faecal samples. This imbalance was before treatment initiation and the administration of the study drug. No between-treatment differences were detected at either the 3- or 9-month sample period either in the predominant bacterial taxa present or in their antibiotic susceptibilities. Conclusions: There was no evidence that sub-antimicrobial doxycycline treatment exerted an effect on the composition or doxycycline resistance level of either the faecal or the vaginal microflora.Keywords: antibiotics; doxycycline; human flora; microbiology; sub-antimicrobial dosage
Document Type: Research article
DOI: 10.1111/j.1600-051X.2005.00840.x
Affiliations: 1: Periodontal Disease Research Clinics, University of Florida, Gainesville, FL, USA; 2: University of Newcastle, Newcastle, UK; 3: University of Kentucky, Lexington, KY, USA; 4: Philips Oral Healthcare, Snoqualmie, WA, USA; 5: CollaGenex Pharmaceuticals Inc., Newtown, PA, USA

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