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

Abstract

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.

Evolution of the Chronic Venous Leg Ulcer Microenvironment and Its Impact on Medical Devices and Wound Care Therapies

“…Chronic VLU is characterized by an alkaline pH ranging from 7.9 to 8.7, along with bacteria such as S. aureus and P. aeruginosa. Interestingly, no direct association has been found between the bacterial profile and pH levels in these ulcers, although infection indeed raises the wound pH [30]. Additionally, for every 1-unit change in pH, a corresponding change in wound size of approximately 116.05 mm 2 can be expected [32].…”

“…According to the studies conducted by Serra et al [36], Rabello Sergio et al (2022) [30], and Thomsen et al (2010) [66], the most common bacteria found in infected venous ulcers include Staphylococcus aureus, Pseudomonas aeruginosa, and Corynebacterium striatum. S. aureus and P. aeruginosa were identified as the most frequently observed bacterial species in venous ulcers, according to both Serra et al (2014) and Rabello Sergio et al (2022) [30] studies. Thomsen et al (2010) [66] also reported that S. aureus, P. aeruginosa, and Enterococcus faecalis were frequently observed in chronic VLU when culture-based methods were used.…”

“…This environment can damage the tissue and further reduce tissue oxygenation, leading to potential complications in the healing process. Additionally, the alkaline wound environment can impair the regulation of metalloproteinases' proteolytic activity, resulting in excessive degradation of extracellular matrix and growth factors, ultimately hindering the healing process [30].…”

“…Even though it may not initially cause a harmful immune response, the microorganisms can express virulence factors, such as the development of biofilms. These biofilms can be tolerant of the host's defense mechanisms, thus creating a risk for infections [30].…”

A importância do enfermeiro para a eficiência da cicatrização de lesões ulcerativas de origem venosa, arterial e mista

“…São necessárias várias etapas de um processo de avaliação para identificar problemas que possam contribuir para o agravo desse tipo de lesão. A avaliação da Brazilian Journal of Development, Curitiba, v.9, n.5, p. 18298-18312, may., 2023 deficiência circulatória, profundidade, extensão, estado nutricional, raça, idade e tempo de início da ferida (9).…”