Monitoring and Molecular Characterization of Staphylococcus aureus Isolated from Chronic Wounds.

OBJECTIVE

Researchers analyzed chronic wounds treated with 2% hydrogel to determine whether the presence of methicillin-resistant Staphylococcus aureus (MRSA) is related to the presence of clinical signs of infection.

METHODS

Thirty-five patients were recruited for this descriptive study using a quantitative approach. Staphylococcus aureus was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Antibiotic susceptibility was determined using a disk diffusion test according to Clinical and Laboratory Standards Institute standards. Polymerase chain reaction, pulsed-field gel electrophoresis, and multilocus sequence typing were performed. Statistical analyses were performed using Spearman correlation coefficients for the variables MRSA and clinical signs of infection.

MAIN OUTCOME MEASURES

The identification of MRSA or methicillin-sensitive S aureus (MSSA), presence or absence of an infection in the wound, and molecular characterization of bacteria were measured.

MAIN RESULTS

Of the 35 patients analyzed, 8 (22.9%) were classified as having an infection in their wounds. Spearman ρ indicated a strong positive correlation between the increase in the number of clinical signs of infection and MSSA (P =.84), but only a moderate positive correlation with MRSA (P =.60). The S aureus clonal pattern was unique for each of the major bacteria isolated. Global MRSA sequence-type clones (ST-1 and ST-72) were detected in 2 patients.

CONCLUSIONS

Compared with those colonized by MSSA, chronic wounds colonized by MRSA did not display a strong correlation with the presence of a greater number of clinical signs of infection.