The discovery and development of antibiotics is one of the medical community’s greatest achievements. Before the advent of antibiotics in 1928, life expectancy in the US was only 47 years. Communicable infectious diseases that once laid waste to entire households were suddenly rendered toothless and innocuous. Antibiotics changed clinical outcomes across virtually every specialty, including childbirth, surgery, trauma, pediatrics, and geriatrics. There is a dark side to this medical triumph, however; as we destroyed the offending microorganisms, we changed them. Many pathogens have now evolved their own defenses against our best arsenal of drugs. Staphylococcus aureus, a common opportunistic bacteria that occupies the surface of nearly everything, has been the target of antimicrobial efforts for many decades. S. aureus has evolved a particular strain that inactivates the drug that originally treated and has become methicillin-resistant Staphylococcus aureus, the dreaded MRSA.
Causes of MRSA
As a result of drug resistance, MRSA was once characterized as a nosocomial or hospital-acquired infection. It was a strain that existed within hospital settings, waiting to infect the old, immunocompromised, or recently incised. However, epidemiology studies have revealed that sometime within the past two decades, MRSA eloped from the clinic and into the general population. Today, many people carry MRSA in their noses, armpits, or groins without knowing it, which has made controlling its spread more difficult. MRSA is “opportunistic” because it does not cause disease until an open wound or a drop in immunity presents a window of opportunity to colonize tissues. These infections cause a host of miseries, including surgical-site infections, pneumonia, sepsis, renal failure, and even death in about 20% of cases. MRSA infections can be the result of inadequate disinfection of a surgical site prior to surgery, an open wound on the body, or from ineffective hand cleansing by hospital staff. Long or synthetic fingernails are very good at harboring MRSA and other pathogens, and as a consequence most healthcare facilities now prohibit anyone with direct patient care duties from wearing them.
Symptoms of MRSA infection
The symptoms of MRSA resemble any other type of infection. If superficial, symptoms include redness, swelling, heat, and pain to the touch. Purulent drainage may be present. An infection of deeper layers of the skin may lead to cellulitis, characterized by large areas of swollen, red, shiny skin that can be very tender, which most commonly occurs on the distal extremities such as the lower legs. MRSA infections within a joint cause severe pain, swelling, and loss of joint mobility. Respiratory MRSA causes severe symptoms, such as high fever, bloody sputum, chest pain, shortness of breath, chills, and significant malaise. Any suspicion of MRSA infection should be treated as an emergency. Since these symptoms mimic other types of infections, a tissue culture must be performed with the appropriate laboratory testing to distinguish MRSA from other pathogens and inform the correct treatment plan.
Treating MRSA infection
The treatment of a MRSA infection depends on the severity and location. Sometimes an infection is very superficial or just contained within a boil, in which case the doctor can make an incision to drain and clean the wound. In this case, only topical antibiotic cream or simple dressing changes and wound care can be used to get rid of the infection. In many cases, though, MRSA can invade deeper tissues of the skin or joint, infect the lungs, or progress to a dangerous blood infection called septicemia, calling for strong antibiotics. Medications can be provided orally or through an IV. For severe or recurrent MRSA infections, the doctor may order placement of a PICC line in the upper arm, which allows for IV administration extended periods of time at home, usually with the assistance of a home health nurse.