Epidemiological differences between the UK and Ireland versus France in Staphylococcus aureus isolates resistant to fusidic acid from community-acquired skin and soft tissue infections.

OBJECTIVES

To characterize the epidemiology of Staphylococcus aureus isolates resistant to fusidic acid isolated from patients with skin and soft tissue infections (SSTIs) in France, the UK and Ireland.

METHODS

One hundred and thirty-six S. aureus isolates with an MIC of fusidic acid above 1 mg/L were isolated during the EPISA study from patients more than 2 years old attending their general practitioners for SSTIs. All isolates were related to clonal complex by a combination of PFGE, spa typing and multilocus sequence typing. The presence of toxin genes and of the fusB determinant was monitored to characterize each represented clonal complex.

RESULTS

Eight different clonal complexes were identified. CC121 constituted the majority of the isolates from Ireland and the UK but was not represented in France. Among the other clonal complexes, CC8 and CC5 were the most common in the three countries, although the number of French isolates was limited. CC121 was the only clonal complex significantly associated with a skin infection, namely impetigo (P < 0.05). Toxin genes were present in CC121 and CC80. The fusB determinant was also detected in the same clonal complexes. Enterotoxins were found in four clonal complexes (CC1, CC5, CC8 and CC22).

CONCLUSIONS

The impetigo clone (CC121: ST123) was present in the majority of S. aureus isolates from the UK and Ireland but was not detected in France. This strain was associated with impetigo, exfoliative toxins and the fusB determinant. No other clonal complex appeared to be dominant in other types of skin infections.