Rates of pyomyositis and myositis also have been on the rise at Texas Children's, and can be correlated to the emergence of CA-MRSA. Among 45 previously healthy children with bacterial pyomyositis or myositis, the cause was S. aureus in 58%. Of 24 community-acquired S. aureus isolates that were available, 15 were MRSA and 9 were MSSA. A total of 16 (including all the MRSA) isolates were found to be USA300, and 17 carried the PVL genes. The presence of MRSA, USA300, and/or the PVL genes was associated with a greater requirement for drainage procedures (Clin. Infect. Dis. 2006;43:953-60).
“Infection of muscles is something we just never saw in the past,” Dr. Kaplan commented.
Pulmonary manifestations are another increasingly common complication of CA-MRSA. An investigation of 70 children with invasive staphylococcal infections at Texas Children's between 2001 and 2004 showed that 47 had MRSA. Compared with 10 who had MSSA, those with MRSA were more likely to have pneumonia, empyema, lung abscess, and atelectasis. The presence of PVL was associated with abnormal chest image findings in patients with secondary pneumonia (Clin. Infect. Dis. 2005;41:583-90).
Influenza complicated by staph infections is also becoming more common, with most of these cases attributable to MRSA. A study by the Centers for Disease Control and Prevention comparing pediatric deaths during three influenza seasons revealed that bacterial coinfection increased substantially, from 6% in 2004-2005 to 15% in 2005-2006 to 34% in 2006-2007. Isolation of S. aureus from a sterile site rose from just 1 case in 2004-2005 to 22 in 2006-2007, of which two-thirds were MRSA.
Disclosures: Dr. Kaplan has received research grants from Pfizer and Cubist Pharmaceuticals.
'Infection of muscles is something we just never saw in the past.'
Source DR. KAPLAN
An axial view of proximal left tibial osteomyelitis with subperiosteal abscess and extraosseous soft tissue inflammation is shown (top). A sagittal view is also shown (bottom).
Source Images courtesy Dr. Sheldon L. Kaplan