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Antibiotic-resistant Propionibacterium acnes among acne patients in a regional skin centre in Hong Kong


  • Conflict of interest
    None declared.

  • Funding sources
    This work was not supported by any funding. The authors have no relationship with any pharmaceutical companies.

N.-M.T. Luk.


Background  There has been no study on antibiotic-resistant Propionibacterium acnes in Hong Kong.

Objective  We investigated the prevalence and pattern of antibiotic-resistant P. acnes and to identify any associated factors for harbouring the resistant strains.

Methods  Culture and sensitivity testing of P. acnes to commonly used antibiotics were performed. Resistance to tetracycline was defined at a minimal inhibitory concentration (MIC) of 2 μg/mL or more; erythromycin at an MIC of 0.5 μg/mL or more; clindamycin at an MIC of 0.25 μg/mL or more according to EUCAST. For breakpoints of doxycycline and minocycline, those with an MIC of 1 μg/mL or more were defined as resistant strains.

Results  Among the 111 specimens collected from 111 patients, 86 strains of P. acnes were recovered, one from each specimen. Twenty-five specimens had no growth. Forty-seven (54.8%) strains were found to be resistant to one or more antibiotics. Forty-six (53.5%), 18 (20.9%), 14 (16.3%), 14(16.3%) and 14 (16.3%) strains were resistant to clindamycin (CL), erythromycin (EM), tetracycline (TET), doxycycline (DOX) and minocycline (MR) respectively. Ten strains (11.6%) had cross resistance between the MLS antibiotics (erythromycin or clindamycin), one strain (1.2%) had cross resistance among the cyclines and 14 strains (16.4%) had cross resistance between the MLS and cycline antibiotics. Binary logistic regression showed an association between MLS antibiotic resistance with an increased age whereas cycline resistance was associated with the duration of treatment.

Conclusions  Antibiotic-resistant P. acnes is prevalent in Hong Kong. Dermatologists should be more vigilant in prescribing antibiotics for acne patients.