Staph Infections Prevalent in EB Skin Wounds

Infection by the bacteria Staphylococcus aureus is detected in most wounds of patients with epidermolysis bullosa (EB), according to an analysis of a U.S. and Canadian database.

The study “Characterization of wound microbes in epidermolysis bullosa: Results from the epidermolysis bullosa clinical characterization and outcomes database” was published in the journal Pediatric Dermatology.

People with EB have fragile skin that can be wounded easily by minor injuries or friction. Despite proper care, patients are at risk of developing chronic wounds that are colonized by bacteria. That can contribute to worsening of the wounds and increases the risk for squamous cell carcinoma (SCC), which is  the second most common form of skin cancer.

In this study, a group of researchers performed an analysis of EB patients registered in the EB Clinical Characterization and Outcomes Database (EBCCOD), which collects information about patients at centers in the U.S. and Canada.

They sought to evaluate the types of bacteria found in wounds of EB patients and better assess their association with risk of SCC.

Of the 717 patients registered in the EBCCOD, 158 (mean age 12.8 years) had at least one sample of their wounds collected for analysis. The majority had been diagnosed with recessive dystrophic EB and 57% had wounds that appeared clinically infected.

In total, the researchers analyzed data from 739 wound cultures. Among the 158 patients, 152 tested positive for a bacterial infection in their wounds. A total of 113 patients (72%) were positive for more than one bacterium.

The most common bacteria were Staphylococcus aureus (detected in 131 patients, 86%), followed by Pseudomonas aeruginosa in 56 patients /37%), Streptococcus pyogenes (34 patients, 22%), Corynebacterium spp. (31 patients, 20%), and Proteus spp. (17 patients, 11%). Other less common bacteria included the coagulase-negative staphylococci (7%), Streptococcus agalactiae (7%), and Serratia marcescens (5%).

Among the patients positive for Staphylococcus aureus, nearly half were positive for the methicillin-resistant Staphylococcus aureus (MRSA), which does not respond to many antibiotics used to treat ordinary staph infections. Another six patients were positive for Staphylococcus aureus resistant to the topical antibiotic mupirocin.

SCC was found in 23 patients. Among the 10 patients with skin cancer and with a bacterial analysis of their wounds, nine were positive for Staphylococcus aureus. Pseudomonas aeruginosa was detected in five and Proteus spp in two. Among the group without skin cancer, Staphylococcus aureus was found in 83% of patients, Pseudomonas aeruginosa in 34%, and Proteus spp in 11%.

Notably, the limited number of patients with skin cancer and recorded wound culture data precluded comparisons between the two groups to identify which microbes confer a significant risk to develop SCC.

Overall, these findings highlight the need for “ongoing antimicrobial strategies to limit antibiotic resistance” among EB patients, the researchers wrote.

“Resistance to many systemic [whole-body] and topical antibiotic agents in individuals with EB supports surveillance cultures with routine testing for mupirocin resistance as a means to guide antibiotic stewardship and patient counselling,” they concluded.