S.E. Donoghue , , D.A. Vekic , R. McFarlane, M.J. Whitfeld
A 59 HIV positive male presented with a multi-loculated abscess to his lower back. A similar lesion had been incised and drained previously with a healing time of 4 weeks observed. There was no associated fever, CD4 count was > 800 and viral load undetectable. The lesion was drained and the seropurulent fl uid sent for culture and microscopy. Leucocytes were observed with no bacteria. Culture demonstrated a pure growth of a coagulase-negative staphylococccus, subsequently identifi ed as Staphylococcus lugdunensis, sensitive to all antibiotics tested, including penicillin. Following drainage and instigation of antibiotic treatment, gradual yet complete resolution was observed. Staph. lugdunensis, like Staph. epidermidis is a coagulase negative staphylococcus although in many respects behaves more like Staph. aureus 1 . It is most commonly isolated as a commensal from the groin although has recently been shown to cause serious infections with high morbidity and mortality, such as endocarditis and infected joint prostheses 2 .
It is now also recognised as being able to cause abscesses, wound infection and cellulitis, with most infec- tions secondary to trauma, surgery or skin disease. This clinical case highlights the need for dermatologists to be aware that laboratory reports stating “no pathogenic organisms identifi ed” do not exclude opportunistic pathogens such as Staph. ludgunensis which have been previously considered only as normal fl ora.