The Effect of Bacterial Colonization on Venous Ulcer Healing

Abstract

To determine the effect of bacterial colonization on venous ulcer healing, 82 patients with 100 venous ulcerated limbs were each studied prospectively for six months. Despite bacteriological swab results, topical or systemic antibiotics were not administered unless cellulitis supervened. Initial ulcer size, length of ulcer history and time to complete healing of colonized and uncolonized ulcers were determined and compared. Organisms were cultured from 83 limbs prior to commencement of treatment, the commonest isolates being Staphylococcus aureaus (48%), mixed coliforms (28%), Pseudomonas aeruginosa (21%) and anaerobes (17%). When compared with ulcers with no bacterial growth, colonized ulcers were of longer duration (p [symbol: see text] 0.01), had a larger initial size (p [symbol: see text] 0.001) and had significantly longer healing time (p [symbol: see text] 0.001). When analysed individually beta-haemolytic streptococci, anaerobes, Staphylococcus aureus and coliforms were associated with delayed healing. Delayed healing was not found with Pseudomonas aeruginosa, although pseudomonas-colonized ulcers were significantly larger and of longer duration than uncolonized ulcers. Bacterial colonization is associated with delayed venous ulcer healing. To further clarify the pathogenicity of colonizing bacteria, however, the effect of their eradiction on healing of venous ulcers needs to be established.

Community surveillance enhances Pseudomonas aeruginosa virulence during polymicrobial infection

“…Recent evidence suggests that the prevalence may be higher because P. aeruginosa occupies deeper sites within the wound, hampering identification via some conventional sampling techniques (20). In addition, chronic wounds containing P. aeruginosa are more severe and heal at a slower rate (10,18,21), which is hypothesized to be mediated in part by synergistic interactions with Gram-positive bacteria, including Staphylococcus aureus. Indeed, in a murine chronic wound model, P. aeruginosa-S. aureus coinfections were shown to be more severe and recalcitrant to antimicrobial treatment than P. aeruginosa monoculture infections (10).…”

Association Between Microbial Bioburden and Healing Outcomes in Venous Leg Ulcers: A Review of the Evidence

“…10,14 Fewer studies comment on anaerobes and the rigor of anaerobic cultivation methods vary widely, but even these studies disagree on the association of anaerobes with healing. 24,34,35,37 Results for Streptococcus species are most consistent, with most studies showing association with ulcers of increased size, longer duration, and healing delay. 24,[34][35][36] Interestingly, the studies that did not find associations between bacterial populations and healing were more likely to exclude patients with clinical signs of infection in the study design (Table 1 vs. Table 2).…”

“…24,34,35,37 Results for Streptococcus species are most consistent, with most studies showing association with ulcers of increased size, longer duration, and healing delay. 24,[34][35][36] Interestingly, the studies that did not find associations between bacterial populations and healing were more likely to exclude patients with clinical signs of infection in the study design (Table 1 vs. Table 2). In all of the studies examined, clinical signs of infection were not defined, except for the report by Moffatt et al, which listed pain, odor, swelling, erythema, and confirmation by microbiological results without further definition.…”

“…24,34,35 However, there are studies that associate S. aureus both with delayed healing 14,36 and smaller, healing ulcers. 23,37 Similarly, Pseudomonas species have been associated both with larger ulcers and delayed healing, 24,[34][35][36]38 whereas other (although fewer) studies have found that ulcers harboring Pseudomonas were more likely to heal normally. 10,14 Fewer studies comment on anaerobes and the rigor of anaerobic cultivation methods vary widely, but even these studies disagree on the association of anaerobes with healing.…”

Management of large chronic venous leg ulcers with negative pressure wound therapy

“…22 Silver is regarded as a broadspectrum agent and shows activity against the pathogens such as Stapylocoocus aureus and Pseudomonas spp., which frequently colonizes chronic venous ulcers. 23 Despite its advantages in treating infected wounds, silver has been demonstrated to be cytotoxic to human keratinocytes and fibroblasts in vitro. 21,24 However, the clinical correlation to support this finding remains unclear.…”