Severe Childhood Pneumonia Linked To Specific Strain Of Staphylococcus Aureus

Authors of a French study in this week’s issue of THE LANCET highlight the link between a specific strain of the bacterium Staphylococcus aureus and a severe form of pneumonia in children.

Between 1986 and 1998, eight cases of community-acquired pneumonia due to S aureus strains carrying the gene for the Panton-Valentine leukocidin (PVL) were recorded in France, six of which were fatal. Jerome Etienne from the Centre Hospitalo-Universitaire of Lyon, France, aimed to assess the clinical features of these eight cases, and those of other cases identified prospectively, and to compare them with the characteristics of patients with pneumonia caused by PVL-negative strains.

Eight retrospective and eight prospective cases of PVL-positive S aureus pneumonia were compared with 36 cases of PVL-negative S aureus pneumonia. The investigators recorded age, length of hospital stay, risk factors for infection, signs and symptoms, laboratory findings, antibiotic treatment, and serial radiological findings for all patients.

The average age was around 15 years for patients with PVL-positive S aureus compared with 70 years for patients who had PVL-negative strains. Influenza-like illness had occurred during the 2 days before hospital admission in 12 of the 16 PVL-positive patients, but in only three of 33 PVL-negative patients. Markers for PVL-positive infections included temperature (greater than 39°C), heart rate above 140 beats per minute, and a reduction in white-blood cells (leucopenia). The survival rate two days after admission was 63% for the PVL-positive patients and 94% for PVL-negative individuals.

Jerome Etienne comments: “PVL-positive strains of S aureus can complicate influenza-like illness in otherwise healthy children and young adults, with rapid progression to severe pneumonia. Although the comparison of the disease manifestations after infection with PVL-positive or PVL-negative S aureus is complicated by the difference in age of the typical patients, we note that the younger and previously healthier group are more at risk of death than their elderly and infirm counterparts.”