Methods: A prospective detailed microbiological analysis was performed in 150 out-patients attending the Wound Healing Research Unit, Cardiff. In addition to routine microbiological analysis, antibiotic susceptibility profiles were determined for all Staphylococcus and Pseudomonas aeruginosa isolates, using disk and strip testing methods. PCR was utilised to identify the mecA gene carriage. Further phenotypic and genotypic analysis of these wound isolates was undertaken using Random Amplified Polymorphic DNA, Pulse Field Gel Electrophoresis and Multi-Locus Sequence Typing.
Results: As part of an audit, 150 patients (attending consecutively) participated in the study, age range 30–88 years, mean wound duration 3.7 years (range 3 months–21 years); mean surface area of the wound 30.3 cm2 (range 5.5 – 306 cm2). Resistance studies demonstrated that S. aureus isolates from 11.3% of patients carried Methicillin resistant Staphylococcus aureus MRSA with PCR revealing that 100% of these carried the mecA gene. Of those wounds that carried MRSA, 4 patients were found to have lost MRSA within a 3 month interval and 2 patients had acquired MRSA. Pseudomonas aeruginosa was isolated from 48 patients (31.8%), with 31.3% of these isolates found to be ciprofloxacin resistant. Other resistances observed were to piperacillin and imipenem (10.4% and 14.6%) respectively.
Conclusion: The results clearly demonstrate the potential role of importance of antibiotic resistant microorganisms in mediating impaired healing and the potential problems they may present in the spread of antimicrobial resistance in the hospital and out-patient settings.