© CDC/ Dr. Richard Facklam
Group A streptococcal infection of injured muscle is a virulent vector of deadly necrotizing fasciitis, myonecrosis, and toxic shock syndrome. Mortality rates in these conditions are between 30% and 70%. Approximately 50% of these affected patients have a deep-seated infection with Group A streptococcal having had a nonpenetrating trauma or even a minor muscle strain. The organism, perhaps circulating in the blood stream from oropharyngeal sources, is attracted to the injured muscle site.
Stephanie Hamilton et al (J Infect Dis. 2008; 198(11):1692-1698) describe the attraction of the Streptococci to vimentin, a protein found on the surface of recently injured muscle cells. Inflammation, muscle regeneration, and vimentin expression are tightly linked processes. After muscle damage, neutrophils arrive to remove damaged muscle cells and are followed by macrophages. The macrophages secrete growth factors and prostaglandins to promote new muscle cells which are covered with vimentin.
Nonsteroidal anti-inflammatory drugs (NSAIDS), taken approximately 72 hours after what may have been a minor muscle injury, can prolong the presence of vimentin thus facilitating the arrival and proliferation of Group A streptococci. These streptococci produce sinister toxins. We should be alert to the unfortunate effect NSAIDS can have on the process of injured muscle repair. They can encourage the growth of a particularly nasty streptococcus.
|Blue Notes Editor:|
Charles Sorbie, MB, ChB, FRCS(E), FRCS(C)
Dr. Charles Sorbie is Professor of Surgery at Queen’s University and a member of the Attending Staff at the General and Hotel Dieu Hospitals in Kingston, Ontario.
A former chairman of the Department of Surgery at Queen’s University, Dr. Sorbie has been President of the Canadian Orthopaedic Research Society, the Canadian Orthopaedic Association, and the Societé Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT).