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Summer Dunshee Microbiology 205 Extra Credit Paper MRSA I am choosing to do a paper on MRSA because my mother in law got it suddenly after a routine hospital visit. It was such a devastating and sudden disease process that I was fascinated to learn more about it. MRSA stands for Methicillin-resistant Staphylococcus aureus. It is caused by a strain of staph bacteria that has become resistant to the antibiotics commonly used to treat typical staph infections. There are many different varieties of Staphylococcus aureus bacteria, called “staph. ” Staph bacteria are normally found on the skin or in the nose of about one-third of the population.
The bacteria are generally harmless unless they enter the body through a cut or other wound, and even then they usually only cause minor skin problems in healthy people. Only about 1 % of the population carries the type of Staph bacteria known as MRSA. Most MRSA infections occur as nosocomial infections, in health care settings, especially hospitals. When it occurs in these settings it is referred to as HA-MRSA, for health care-associated MRSA. HA-MRSA infections typically are associated with invasive procedures or devices, such as surgeries, intravenous tubing or artificial joints.
Another type of MRSA infection can be found in healthy people, in the wider community. This form is called CA-MRSA, for community-associated MRSA. MRSA can begin as many forms: skin boil (pus-filled infections of hair follicles), cellulitis, bumps in the skin, abscesses, sty (in the eye), carbuncles (infections larger than an abscess, usually with several openings to the skin), impetigo (a skin infection with pus-filled blisters), and rash. These are the early signs, symptoms, and stages of MRSA infection. One major problem with MRSA is that occasionally the skin infection can spread to almost any other organ in the body.
When this happens, more severe symptoms develop. MRSA that spreads to internal organs can become life threatening. Fever, chills, low blood pressure, joint pains, severe headaches, shortness of breath, and “rash over most of the body” are symptoms that need immediate medical attention, especially when associated with skin infections. MRSA is spread by skin-to-skin contact. It can be contagious from person to person; sometimes direct contact with an MRSA-infected person is not necessary because people who touch materials or surfaces contaminated with MRSA organisms can also spread the bacteria.
There are two major ways people become infected with MRSA. The first is physical contact with someone who is either infected or is a carrier of MRSA. The second way is indirect, to physically contact MRSA on any objects such as door handles, floors, sinks, or towels that have been contaminated by a MRSA-infected person or carrier. Normal, intact skin tissue in people does not allow MRSA infection to develop; however, if there are cuts, abrasions, or their skin flaws such as psoriasis, MRSA may proliferate. At risk populations include high school wrestlers, childcare workers, armed service personnel, and people who live in crowded conditions.
People with higher risk for MRSA infection are those with obvious skin breaks, (such as post surgery, traumatic wounds, burn patients, intravenous lines, catheters, skin ulcers, etc. ), and people with depressed immune systems, (elderly, HIV patients, infants), or those with chronic diseases, (cancer, diabetes, etc. ). People with pneumonia due to MRSA can transmit MRSA by airborne droplets. Health-care workers as a group are repeatedly exposed to MRSA-positive patients and can have a high rate of infection if precautions are not taken.
As long as people, including carriers, have MRSA organisms in wounds or droplets that are shed into the environment, they are contagious. Carriers must be very careful about personal hygiene, (especially coughs, itching, or scratching skin, and sneezing), as they may be contagious indefinitely. MRSA can be diagnosed by checking a tissue sample or nasal secretion for signs of drug-resistant bacteria. The sample is sent to a lab where it is placed in a dish of nutrients that encourage bacterial growth. This test takes about 48 hours.
Newer tests are now available that test the Staph DNA, they are available in a matter of hours For treatment, both community and health care associated MRSA still respond to certain antibiotics. In some cases, antibiotics may not be necessary. Often the first step in treatment by doctors is to drain the wound, caused by MRSA, rather than treat the infection with drugs. If antibiotic treatment is clinically indicated, it should be guided by the susceptibility profile of the organism. Certain specific antibiotics, such as vancomycin, linezolid, and others, often in combination with vancomycin, an still treat many MRSA infections. Some strains of MRSA are now resistant to vancomycin. It is important to act to prevent MRSA from occurring in the first place. In the hospital, people who are infected or colonized with MRSA often are placed in isolation as a precaution to prevent the spread. Visitors and health care workers caring for people in isolation may be required to wear protective garments and must follow strict hand hygiene procedures. Contaminated surfaces and laundry items should be properly disinfected. To prevent MRSA in the community careful hand washing is the best defense against germs.
Wounds should be kept covered with sterile, dry bandages until they heal. The pus from infected sores may contain MRSA, and keeping wounds covered will help keep bacteria from spreading. People at risk should avoid sharing personal towels, sheets, razors, clothing, athletic equipment, etc. References: D’Agata EM, Webb GF, Horn MA, et al. Modeling the invasion of community-acquired methicillin-resistant Staphylococcus aureus into hospitals. Clin Infect Dis 2009, 48: 274-84. Edelsberg J, Taneja C, Zervos M, et al. Trends in US hospital admissions for skin and soft tissue infections. Emerg Infect Dis 2009; 15;1516-8.