Does pH Influence the Bacterial Profile of Chronic Lesions? An Analysis of Venous Ulcer Samples.

Objective: To analyze the pH of venous ulcers and their relationship with the quantitative and qualitative bacterial profile of the wounds.

Methods: Cross-sectional study carried out through data collection and microbiologic analyses of samples obtained from 35 venous ulcers. Investigators performed pH measurement with indicator strips and collected biologic material using swabs. After aerobic and anaerobic cultivation, colony-forming units (CFUs) were counted and used for bacterial identification via mass spectrometry.

Results: The pH values ranged from 7.9 to 8.7; 8.5 (37.1%) was the most frequent, followed by 8.3 (28.6%). The most common species were Staphylococcus aureus (68.6%), Pseudomonas aeruginosa (62.9%), Proteus mirabilis (45.7%), and Corynebacterium striatum (40.0%). The number of CFUs ranged from 0 to 200,000 in both anaerobiosis and aerobiosis and was predominantly between 1,000 and 10,000 (37.1%) in anaerobiosis and between 10,000 and 100,000 (37.1%) in aerobiosis. No association was found between the different pH values and the variation in CFUs in anaerobiosis (P = .21) and aerobiosis (P = .55) or by bacterial species identified: S aureus (P = .41), P aeruginosa (P = .29), P mirabilis (P = .19), and C striatum (P = .96).

Conclusions: The pH of venous ulcers did not influence bacterial profile in quantitative or qualitative parameters.