Staphylococcus aureus is a bacterium that exists in two strains, methicillin-sensitive and methicillin-resistant, or MRSA. The latter strain of staph has become resistant to the antibiotics commonly used to treat ordinary staph infections, according to MayoClinic.com.
According to "Harrison's Principles of Internal Medicine," the prevalence of methicillin-resistant S. aureus in hospitals increased from 2 percent to 64 percent between 1974 and 2005. Over the past decade, MRSA infections have become commonplace in communities outside the hospital setting, as stated by Dr. AW Karchmer in the journal "Clinical Infectious Diseases."
MRSA Pneumonia
A1999 study in the journal "Clinical Infectious Diseases" compared 86 ICU patients with MRSA pneumonia and MSSA pneumonia. The MRSA pneumonia patients had significantly greater rates of bacteremia, septic shock and mortality than the MSSA patients.
The increase in MRSA in hospitals, combined with prolonged intubation and respiratory support of elderly patients, has resulted in an increase of MRSA pneumonia, according the journal "Clinical Infectious Diseases." MRSA now accounts for 20 to 40 percent of all hospital-acquired pneumonia and ventilator-associated pneumonia. Community-acquired MRSA has also been associated with sepsis and rapidly fatal pneumonia.
MRSA Bacteremia
According to a 2008 article in the journal "Clinical Infectious Diseases," the management of methicillin-resistant S. aureus bacteremia and infection of the heart, or endocarditis, is a challenge due to the increasing rates of this infection globally. Establishing the extent of infection is considered an important aspect of the management of S. aureus bacteremia.
MRSA Skin Infections
According to the "New England Journal of Medicine," community-acquired methicillin-resistant S. aureus has become the most frequent cause of skin and soft tissue infections presenting to emergency departments in 11 cities in the United States. This infection often begins as a painful boil. Community-acquired outbreaks of MRSA skin infection have occurred among prisoners, intravenous drug users, athletes, military and men who have sex with men, according to a study in the "New England Journal of Medicine."
Most patients in the study were treated with cephalexin and dicloxacillin, to which MRSA isolates are not susceptible. Consequently, other antibiotics like clindamycin, trimethoprim--sulfamethoxazole and doxycycline have been recommended to cover MRSA skin infections acquired in the community.
References
- "Harrison's Principles of Internal Medicine"; Dennis Kasper, M.D., et al.; 2005
- "Clinical Infectious Diseases"; Methicillin-Resistant Staphylococcus aureus: An Evolving Clinical Challenge; AW Karchmer; June 2008
- "New England Journal of Medicine"; Methicillin-resistant S. aureus infections among patients in the emergency department; GJ Moran; August 2006
- Mayo Clinic: MRSA Infection
- "Clinical Infectious Diseases"; Pneumonia caused by methicillin-resistant Staphylococcus aureus; Ethan Rubinstein, M.D.; June 2008
