A total of 107 antibiotic-resistant propionibacteria were isolated from the face of 102 Egyptian acne patients, dermatology staff and controls. Erythromycin-clindamycin-resistant propionibacteria were chosen to detect ern(X) gene and it was detected in 29 of 107 (27%) strains. However, just 7 strains had IS 12491, 3 of them had also Tn5432. The erm(X) gene which is not carried on Tn5432 confers inducible resistance to telithromycin by erythromycin or clindamycin. The DNA sequences of the PCR amplification products of this new erm(X)-mediated antibiotic resistance showed >99% identity to the erm(X) gene isolated from a Corynebacterium jeikeium. Southern blotting analysis of the erm(X)-specific probe shows that there were two copies of this resistance gene integrated within the chromosomal DNA. This is the first report of erm(X) being carried by Propionibacterium acnes outside Europe. Whilst the gene is associated with Tn5432 in some strains, the data suggests other genetic element carrying erm(X). The high carriage of erm(X) may affect the efficacy of clindamycin and macrolides for acne treatment in Egypt. (C) 2010 Elsevier Ltd. All rights reserved.