Widespread use of antibiotics has provoked the development of resistance to specific antibiotics among certain strains of disease-causing bacteria. Bacterial strains known as methicillin-resistant Staphylococcus aureus, or MRSA, stand as hallmark examples of the acquisition of antibiotic resistance. Despite the single antibiotic reference in the name, the Centers for Disease Control and Prevention reports that MRSA is resistant to multiple antibiotics, including penicillin, oxacillin, amoxicillin, methicillin and cephalosporins. MRSA infection treatment requires the judicious selection of antibiotics to which the bacteria remain sensitive.
Clindamycin
MRSA infections acquired outside a hospital or long-term care facility are termed community-associated MRSA infections. In 2006, the Centers for Disease Control and Prevention convened a meeting of infectious disease experts to determine the best strategies for treating community-associated MRSA infections. The experts developed a list of possible oral antibiotics to be used for these infections, noting that the final choice remains in the hands of the treating physician. The Centers for Disease Control and Prevention, the American Medical Association and the Infectious Disease Society of America have endorsed the list of antibiotic options set forth by the expert panel.
Clindamycin is a CDC-recommended antibiotic option for the outpatient treatment of MRSA infections. Notably, some MRSA strains are resistant to clindamycin. In a 2008 study published in the "Journal of Antimicrobial Therapy," Vicki Luna, Ph.D., and colleagues report a clindamycin resistance rate of approximately 4 percent among 170 community-associated MRSA bacterial samples.
Tetracyclines
Tetracycline antibiotics, including minocycline and doxycycline, remain a CDC-recommended option for the outpatient treatment of community-associated MRSA infections. CDC notes that tetracyclines are not recommended for pregnant women or children younger than age 8. Although some MRSA strains prove resistant to tetracyclines, Dr. Jose Bordon and colleagues report in a 2010 article published in "Diagnostic Microbiology and Infectious Disease" that the rate of tetracycline resistance decreased from 1996 to 2008.
Trimethoprim-Sulfamethoxazole
The combination antibiotic trimethoprim-sulfamethoxazole is among the CDC-recommended options for the outpatient treatment of community-associated MRSA infections. Trimethoprim-sulfamethoxazole is not recommended for infants younger than 2 months old or women in the third trimester of pregnancy. The 2010 article from Bordon and colleagues reports that the prevalence of trimethoprim-sulfamethoxazole resistance among isolated strains of MRSA fell from 1996 to 2008.
Linezolid
The U.S. Food and Drug Administration has approved linezolid for the treatment of MRSA infections, and the drug is among the CDC-recommended antibiotic options for the treatment of community-associated MRSA infections. CDC additionally recommends consultation with an infectious disease specialist prior to the use of this medication. Linezolid may cause serious side effects, including suppression of bone marrow blood cell production and a severe metabolic disturbance known as lactic acidosis.
References
- Centers for Disease Control and Prevention: National MRSA Education Initiative: Preventing MRSA Skin Infections, Information for Healthcare Professionals
- Centers for Disease Control and Prevention: Strategies for Clinical Management of MRSA in the Community: Summary of an Experts' Meeting Convened by the Centers for Disease Control and Prevention, March 2006
- "Journal of Antimicrobial Therapy"; Susceptibility of 170 Isolates of the USA300 Clone of MRSA to Macrolides, Clindamycin and the Novel Ketolide Cethromycin; Vicki Ann Luna, Ph.D., et al; 2008
- "Diagnostic Microbiology and Infectious Disease"; Methicillin-resistant Staphylococcus aureus Resistance to Non-beta-lactam Antimicrobials in the United States from 1996 to 2008; Jose Bordon, M.D., et al.; August 2010
- Centers for Disease Control and Prevention: Outpatient Management of Skin and Soft Tissue Infections in the Era of Community-Associated MRSA
