Changes in skin microbiota of patients associated with treatment by Isotretinoin

Williams , D. Ross and Thomas, Angela E. and Hepburn, Neil C. and Watts, Toni and Dixon, Ron A. (2004) Changes in skin microbiota of patients associated with treatment by Isotretinoin. In: 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy, November 2004, Washington, DC.

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Abstract

Isotretinoin, a retinoid – can be used to treat patients with moderate to severe acne despite the adverse effects of mucosal surface drying and the contraindication of use during pregnancy. Commonly, in clinical practice, patients prescribed systemic isotretinoin have previously not responded to treatment with oral or topical antibiotics. Broad-spectrum antibacterial therapy attempts have never the less promoted changes in the diversity and antibiotic resistance status of the patients’ skin microbiota. The present study investigated the recovery and analysis of skin organisms from 56 patients (mean age 23 y range 15-37 y) before, during and after treatment with a 16-week course of isotretinoin (1 mg/kg body weight).
The number of aerobic bacterial isolates (presumptive staphylococci) recovered from Baird-Parker agar (BP) and from Mueller-Hinton agar (MH) and also anaerobic isolates on Tryptone Yeast extract glucose agar (TYEg) (presumptive Propionibacterium acnes) from each of three specific sites per patient were compared with age-matched controls of healthy volunteers. Both patients and controls had generally similar numbers of organisms on the nares, cheek and toe webs, before treatment, whereas all patients showed a significant reduction in bacteria recovered from one site during and after 16 weeks of isotretinoin treatment. The majority of the patients had a greater reduction (1-2 log) for the cheek site than either nares or toe webs both of which showed minimal reduction if any. Results from this study show a pronounced reduction in the number of bacteria recovered from the treated group immediately following isotretinoin compared to untreated controls. Since isotretinoin has little known antibacterial activity the observed reductions would suggest that the effect is mediated through changes in the skin nutritional micro-environment.

Item Type:Conference or Workshop Item (Poster)
Additional Information:Isotretinoin, a retinoid – can be used to treat patients with moderate to severe acne despite the adverse effects of mucosal surface drying and the contraindication of use during pregnancy. Commonly, in clinical practice, patients prescribed systemic isotretinoin have previously not responded to treatment with oral or topical antibiotics. Broad-spectrum antibacterial therapy attempts have never the less promoted changes in the diversity and antibiotic resistance status of the patients’ skin microbiota. The present study investigated the recovery and analysis of skin organisms from 56 patients (mean age 23 y range 15-37 y) before, during and after treatment with a 16-week course of isotretinoin (1 mg/kg body weight). The number of aerobic bacterial isolates (presumptive staphylococci) recovered from Baird-Parker agar (BP) and from Mueller-Hinton agar (MH) and also anaerobic isolates on Tryptone Yeast extract glucose agar (TYEg) (presumptive Propionibacterium acnes) from each of three specific sites per patient were compared with age-matched controls of healthy volunteers. Both patients and controls had generally similar numbers of organisms on the nares, cheek and toe webs, before treatment, whereas all patients showed a significant reduction in bacteria recovered from one site during and after 16 weeks of isotretinoin treatment. The majority of the patients had a greater reduction (1-2 log) for the cheek site than either nares or toe webs both of which showed minimal reduction if any. Results from this study show a pronounced reduction in the number of bacteria recovered from the treated group immediately following isotretinoin compared to untreated controls. Since isotretinoin has little known antibacterial activity the observed reductions would suggest that the effect is mediated through changes in the skin nutritional micro-environment.
Keywords:ac
Subjects:C Biological Sciences > C180 Ecology
C Biological Sciences > C440 Molecular Genetics
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
ID Code:6077
Deposited By:INVALID USER
Deposited On:25 Aug 2012 22:07
Last Modified:25 Aug 2012 22:07

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