Bacterial colonization of chronic leg ulcers: current results compared with data 5 years ago in a specialized dermatology department

Background In nearly every chronic wound different bacteria species can be detected. Nevertheless, the presence of such microorganisms is not necessarily obligatory associated with a delayed wound healing. But from this initially unproblematic colonization an infection up to a sepsis can arise in some patients. The aim of our clinical investigation was to analyse the spectrum of microbial colonization of patients with a chronic leg ulcer in our specialized dermatological outpatient wound clinic, and to compare them with the results of comparable data already collected 5 years ago. Objectives In our retrospective investigation the results of bacteriological swabs were documented in 100 patients with a total of 107 chronic leg ulcers. All patients visited the specialized wound outpatient clinic, Department of Dermatology, University of Essen in Germany. Methods A total of 60 patients were female, 40 were male. The mean age was 65 years. Altogether a total of 191 bacterial isolates and 25 different bacterial species could be identified. Results The most often detected species were Staphylococcus aureus (n = 60), Pseudomonas aeruginosa (n = 36) as well as Proteus mirabilis (n = 17). In 10 patients (10%) we identified a colonization with methicillin resistant S. aureus (MRSA). Merely in 6 patients the taken swabs were sterile. Five years ago a comparable investigation was already carried out in our wound outpatient clinic. At that time we could detect in particular more frequent MRSA (21.5% vs. 10%) and rarely P. aeruginosa (24.1% vs. 33.6%). Conclusion The results of our investigation demonstrate the current spectrum of the bacterial colonization in patients with chronic leg ulcers in a university dermatological wound centre in comparison to the last 5 years. In our institution we were able to demonstrate a shift of the detected bacterial species from gram‐positive in direction to gram‐negative germs. Beside the already known problems with MRSA, in future therapeutic strategies in patients with chronic leg ulcers the increasing amount of gram‐negative bacteria and especially of P. aeruginosa should considered.