Community-acquired MRSA bacteraemia: four additional cases including one associated with severe pneumonia

To the Editor: Collins and colleagues1 reported a case of bacteraemic community-acquired MRSA (CAMRSA) infection that they believed to be the first reported in Australia. One of us (G N) published a reference to a case of septicaemia and osteomyelitis in Brisbane caused by CAMRSA in 2000.2 This severe case occurred in a previously healthy 16-year-old boy with no risk factors for MRSA infection who, after prolonged ventilatory and inotropic support and vancomycin therapy, required a long period of rehabilitation. A further two cases of septicaemia occurred in Ipswich and will soon be published as part of a study of CAMRSA conducted in 2000–2001.3

We recently encountered another case involving a previously well 23-year-old man who presented to the emergency department with a large abscess on his upper lip and extensive cellulitis of the surrounding face and neck, and with left-sided pleuritic chest pain and associated fevers and rigors. The patient denied previous antibiotic use or contact with healthcare facilities at any time in the past. There was no history of injecting drug use or trauma. Staphylococcus aureus was isolated from blood cultures, and resistance to oxacillin and susceptibility to erythromycin, clindamycin, tetracycline, gentamicin, ciprofloxacin, fusidic acid, rifampicin, and vancomycin was shown. Specimens from operative debridement of the facial abscess yielded S. aureus with the same susceptibility pattern. Chest x-rays showed extensive consolidation of the left lower lobe and an associated loculated pleural effusion. Clinical, radiological, and echocardiographic evaluations did not reveal another focus of infection. The patient was treated with intravenous vancomycin for three weeks followed by oral clindamycin, with complete clinical resolution.

It is now clear that CAMRSA infection may result in severe, life-threatening sepsis. The possibility of pneumonia associated with CAMRSA is of particular concern. A 1999 report from Minnesota and North Dakota documented four deaths in children from CAMRSA, including two with necrotising pneumonia.4 A further two fatal cases of necrotising pneumonia caused by CAMRSA were recently reported from France.5 The strains involved in all of these cases carry the gene for Panton-Valentine (P-V) leukocidin, a staphylococcal toxin that has been shown to be strongly associated with cases of severe superficial abscesses and necrotising pneumonia.6

As the strain of CAMRSA most commonly encountered in Eastern Australia also carries the P-V leukocidin gene (Professor J Etienne, Faculty of Medicine, Claude Bernard Lyon 1 University, personal communication), doctors should be aware of the possibility of severe community-acquired pneumonia caused by this organism.