Enterococcus faecalis as a cause of perianal dermatitis

Abstract

I read with interest the report by Theotokatou and colleagues [1] of intra-family spread of perianal dermatitis that was attributed to Enterococcus faecalis. This is said to be the first report attributing Enterococcus spp. as a cause of perianal dermatitis in children, although enterococci have previously been reported as a cause of perianal infections in adult patients with neutropenia [2]. However, before enterococci can be added to the list of microbial causes of perianal cellulitis in otherwise healthy children it is important to consider the strength of the evidence for attributing a direct pathogenic role to a microorganism that is a ubiquitous lower gastrointestinal tract commensal. The report by Theotokatou and colleagues [1] falls short of establishing a direct causal relationship in a number of aspects. First, the index case had been symptomatic for at least two weeks before he underwent microbiological investigation. This raises the possibility that enterococci may have secondarily colonised or infected perianal skin that had been infected earlier by another microorganism. Although the second case had a much shorter symptomatic period before being investigated and treated I note that E. faecalis was only isolated from faeces, a not unexpected finding. Second, it is not clear how the authors concluded that E. faecalis was the responsible organism after culture of perianal skin and faeces; presumably enterococci were not isolated in pure culture from these samples. Finally, the apparent response to treatment with cefuroxime, an antibiotic to which enterococci are intrinsically resistant, is surprising. The authors do not describe how E. faecalis was identified by their laboratory; however, the antibiotic susceptibility results they report are untypical of E. faecalis (resistant to coamoxiclav and susceptible to cefuroxime) [3]. In summary, the detection of enterococci in these cases seems more likely to represent colonisation or secondary infection, rather than E. faecalis being the primary cause of the perianal dermatitis.