QUALITATIVE AND QUANTITATIVE MICROBIOLOGICAL INVESTIGATION IN CHRONIC LEG ULCERS

The purpose of the study was to identify qualitative and quantitative variability of bacteria species in 18 chronic leg wounds.

We enrolled 18 patients (2 men and 16 women) with chronic ulcers (12 venous ulcers and 6 pyoderma gangrenosum). The ulcers were characterized by different duration (from 6 months to 20 years) and by different clinical situations.

Biopsy samples were collected with a biopsy punch in local anesthesia at 2 different depth (- 3 mm and -5 mm) on the edges and on the wound beds. The specific and detailed analysis of the microbiological parameters was determined by qualitative and quantitative evaluation of the bacterial component by mass spectrometry (Maldi Tof).

Heterogeneous bacteria (Gram+ and Gram-) were present at – 3and -5 mm in the tested samples. The same bacteria were found at -3 and -5mm in the presence of infection, while in case of critical colonization, the bacterial species were different in the two samples. Another interesting aspect that emerged was that half of the patients with microbiological signs of deep infection didn’t have clinical signs of infection at the time of the visit. In addition, in chronic venous ulcers the bacterial species were polymicrobial (Gram+ and Gram-), whereas in pyoderma gangrenosum the bacterial species found were monomicrobial, with predominance of Gram +.

This study highlights the importance of carrying out more quantitative type of laboratory investigation to support optimal therapeutic management.