eComment. A change in the microbial spectrum in deep sternal wound infections

I read the article by Steingrimsson et al. with interest [1].

Since the introduction of negative-pressure wound therapy in the management of deep sternal wound infection (DSWI) in 1999, various centres, albeit without absolute comparable study populations, have reported an alarming increase in the incidence of the deceptive coagulase-negative Staphylococcus (CoNS) as the major causative organism [2]. This elegant study by Steingrimsson and colleagues supports the concern. They identified CoNS as the sole pathogen in 70% of cases with DSWI between 2005–2010, when compared to 30% between 2000–2005 (p = 0.01). Up to 2007, Staphylococcus aureus and/or CoNS were the most prevalent pathogens encountered in DSWI [3]. Recently in 2009, Ennker et al. and Eriksson et al. reported a CoNS incidence of 38% and 62% in their single-institution case-series of DSWI, respectively. One could be forgiven in thinking this to be a purely Nordic phenomenon – this is not the case. In their study over a period of 15 years, Matros and colleagues [4] found CoNS, cultured in 49% of 285 sternal wounds, to be the most prevalent pathogen. Patients with CoNS-related DSWI may present late (> 3 weeks), with less obvious symptoms and less pronounced infective markers (C-reactive protein, white blood cell count). Furthermore, these patients are often afflicted with diabetes mellitus, chronic obstructive pulmonary disease (COPD) or suffer from obesity. According to some, methicillin-resistance of the Staphylococci can be above 90% in DSWI associated with CoNS. Fortunately, as Steingrimsson and colleagues point out, the incidence of MRSA in Iceland has remained low.

A point of further interest is that bleeding occurred in both groups [1]. As expounded elsewhere, the exact relation to negative-pressure wound therapy has yet to be clarified [5].

Note: complete list of references is available from the author.

Conflict of interest: none declared.