MRSA infections facts
What is methicillin-resistant Staphylococcus aureus (MRSA)?
MRSA stands for methicillin-resistant Staphylococcus aureus (S. aureus) bacteria. This organism is known for causing skin infections in addition to many other types of infections. There are other designations in the scientific literature for these bacteria according to where the bacteria are acquired by patients, such as community-acquired MRSA (also termed CA-MRSA or CMRSA), hospital-acquired or health-care-acquired MRSA (also termed HA-MRSA or HMRSA), or epidemic MRSA (EMRSA). Statistical data suggest that as many as 19,000 people per year have died from MRSA in the U.S. Data supplied by the CDC in 2011 suggests this number has declined by about 54% from 2005 to 2011, in part, because of prevention practices at hospitals and home care. In addition, hospital deaths from MRSA infection have declined by about 9,000 per year from 2005-2011. However, the CDC recently estimated about 80,000 infections with 11,000 deaths occurred in 2011, but they suggest that a far greater number of minor infections occurred in both the community and in hospitals.
Although S. aureus has been causing infections (staph infections) probably as long as the human race has existed, MRSA has a relatively short history. MRSA was first noted in 1961, about two years after the antibiotic methicillin was initially used to treat S. aureus and other infectious bacteria. The resistance to methicillin was due to a penicillin-binding protein coded for by a mobile genetic element termed the methicillin-resistant gene (mecA). In recent years, the gene has continued to evolve so that many MRSA strains are currently resistant to several different antibiotics such as penicillin, oxacillin, and amoxicillin (Amoxil, Dispermox, Trimox). HA-MRSA are often also resistant to tetracycline (Sumycin), erythromycin (E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone), and clindamycin (Cleocin). In 2009, research showed that many antibiotic-resistant genes and toxins are bundled and transferred together to other bacteria, which speed the development of toxic and resistant strains of MRSA. S. aureus is sometimes termed a superbug because of its ability to be resistant to several antibiotics.
In addition, these organisms have been termed "flesh-eating bacteria" because of their occasional rapid spread and destruction of human skin. Additionally, a number of older (2004-2008) web and popular press articles are titled or include the erroneous term "MRSA virus." This is a misnomer that has confused many people; there is no contagious MRSA virus, and if readers examine these articles, they may realize the content is usually about MRSA bacteria.
Learn more about: oxacillin | Sumycin | Eryc | Ery-Tab | PCE | Pediazole
Unfortunately, MRSA strains of bacteria can be found worldwide. In general, healthy people with no cuts, abrasions, or breaks on their skin are at low risk for getting infected. However, the bacteria can be passed from person to person by direct contact with infected skin, mucus, or droplets spread by coughs in both adults and children. Indirect contact also can spread the bacteria; for example, touching items like towels, utensils, clothing, or other objects that have been in contact with an infected person can spread the bacteria to other uninfected individuals. Investigators estimate that about one out of every 100 people in the U.S. are colonized with MRSA (have the organisms in or on their body but not causing infection), and these individuals may transmit MRSA bacteria to others by the same methods listed above. Another term for people colonized with MRSA is "carrier" which means the person carries the organism in or on the body and may transfer the organism to another person who subsequently may become infected. A common place for carriers to harbor MRSA organisms is the nose.
What does a MRSA infection look like?
On the skin, MRSA infection may begin as a reddish rash with lesion(s) that looks like a pimple or small boil. Often it progresses to an open, inflamed area of skin (as pictured below) that may weep pus or drain other similar fluid. In some instances, it may appear as an abscess, a swollen, tender area, often with reddish skin covering. When the abscess is cut open or spontaneously bursts open, pus drains from the area.
What does a MRSA infection look like?What are the risk factors for MRSA infections?
People with higher risk of MRSA infection are those with obvious skin breaks (for example, patients with surgical or traumatic wounds or hospital patients with intravenous lines, burns, or skin ulcers) and people with depressed immune systems (infants, the elderly, or HIV-infected individuals) or those with chronic diseases (diabetes or cancer). People with pneumonia (lung infection) 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. Consequently, health-care workers and patient visitors should use disposable masks, gowns, and gloves when they enter the MRSA-infected patient's room. 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.
What are the signs and symptoms of a MRSA infection?
Most MRSA infections are skin infections that produce the following signs and symptoms:
Most of the above signs and symptoms represent the early stages of MRSA infections. One major problem with MRSA (and occasionally with other staph infections) 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. However, some infections can spread to or originate in areas like the lungs, ears, or sinuses. Some CA-MRSA and HA-MRSA infections become severe, and complications such as endocarditis, necrotizing fasciitis, osteomyelitis, sepsis, and death may occur.
How is a MRSA infection transmitted or spread?
MRSA infections are contagious from person to person; occasionally direct contact with a MRSA-infected person is not necessary because the bacteria can also be spread by people who touch materials or surfaces contaminated with MRSA organisms. 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 (people who are not infected but are colonized with the bacteria on their body) of MRSA. The second way is for people to physically contact MRSA on any objects such as door handles, floors, sinks, or towels that have been touched by a MRSA-infected person or carrier. Normal skin tissue in people usually does not allow MRSA infection to develop; however, if there are cuts, abrasions, or other skin flaws such as psoriasis (a chronic inflammatory skin disease with dry patches, redness, and scaly skin), MRSA may proliferate. Many otherwise healthy individuals, especially children and young adults, do not notice small skin imperfections or scrapes and may be lax in taking precautions about skin contacts. This is the likely reason MRSA outbreaks occur in diverse types of people such as school team players (like football players or wrestlers), dormitory residents, and armed-services personnel in constant close contact. A recent example of this spread of MRSA occurred in three NFL football players, all members of the same team, Tampa Bay. Three players got skin infections, and one had to undergo foot surgery to rid the player of recurrent MRSA infection.
How is a MRSA infection diagnosed?
Most doctors start with a complete history and physical exam of the patient to identify any skin changes that may be due to MRSA, especially if the patient or caretaker mentions a close association with a person who has been diagnosed with MRSA. A skin sample, sample of pus from a wound, or blood, urine, or biopsy material (tissue sample) is sent to a microbiology lab and cultured for S. aureus. If S. aureus is isolated (grown on a Petri plate), the bacteria are then exposed to different antibiotics, including methicillin. S. aureus bacteria that grow well when methicillin is in the culture are termed MRSA, and the patient is diagnosed as MRSA infected. The same procedure is done to determine if someone is a MRSA carrier (screening for a carrier), but sample skin or mucous membrane sites are only swabbed, not biopsied. These tests help distinguish MRSA infections from other skin changes that often appear initially similar to MRSA, such as spider bites and skin changes that occur with Lyme disease. These tests are very important; misidentification of a MRSA infection may cause the patient to be treated with other agents like dapsone (used for spider bites). This can result in progression of the MRSA infection and even other complications due to the dapsone.
In 2008, the U.S. Food and Drug Administration (FDA) approved a rapid blood test (StaphSR assay) that can detect the presence of MRSA genetic material in a blood sample in as little as two hours. The test is also able to determine whether the genetic material is from MRSA or from less dangerous forms of staph bacteria. The test (PCR based) is not recommended for use in monitoring treatment of MRSA infections and should not be used as the only basis for the diagnosis of a MRSA infection. In addition, there are new screening tests that report detecting or ruling out MRSA infections in about five hours.
How should caregivers treat MRSA patients at home?
The CDC states that healthy caregivers are unlikely to become infected while caring for MRSA patients at home if they do the following:
What is the treatment for a MRSA infection?
As stated by the U.S. Centers for Disease Control and Prevention (CDC):
Fortunately, many MRSA infections still can be treated by certain specific antibiotics (for example, vancomycin [Vancocin], linezolid [Zyvox], and others, often in combination with vancomycin). Most moderate to severe infections need to be treated by intravenous antibiotics, usually given in the hospital setting. Some CA-MRSA strains are susceptible to trimethoprim-sulfamethoxazole (Bactrim), doxycycline (Vibramycin), and clindamycin (Cleocin); although reports suggest clindamycin resistance is increasing rapidly. In addition, some strains are now resistant to vancomycin. In 2011, researchers developed a chemical change in the antibiotic vancomycin that rendered vancomycin-resistant MRSA susceptible to the drug. It is not available commercially, but this discovery, along with ongoing research, is important because it may expand treatment possibilities for MRSA and other drug-resistant bacteria such as VRE (vancomycin-resistant enterococci). Another drug, Teflaro, has been approved for treatment by the FDA for MRSA infections.
Learn more about: Zyvox | Bactrim | Vibramycin
A good medical practice is to determine, by microbiological techniques done in a lab, which antibiotic(s) can kill the MRSA and use it alone or, more often, in combination with additional antibiotics to treat the infected patient. Since resistance can change quickly, antibiotic treatments may need to change also. Many people think they are "cured" after a few antibiotic doses and stop taking the medicine. This is a bad decision because the MRSA may still be viable in or on the person and thus is capable of reinfecting the person or others. Also, the surviving MRSA may be exposed to low antibiotic doses when the medicine is stopped too soon; this low dose may allow MRSA enough time to become resistant to the medicine. Consequently, MRSA patients (in fact, all patients) treated with appropriate antibiotics should take the entire course of the antibiotic as directed by their doctor. A note of caution is that, in the last few years, there have been reports of a new strain of MRSA that is resistant to vancomycin (VRSA or vancomycin-resistant S. aureus) and other antibiotics. Currently, VRSA is detected more often than a few years ago, but if it becomes widespread, it may be the next superbug.
The CDC recommends clinicians use the 2011 guidelines published by the Infectious Diseases Society of America (IDSA) that details treatments. The 38-page set of guidelines can be found at http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/MRSA.pdf.
Research is ongoing; in 2013, new discoveries about the bacterial cell wall configuration are leading researchers to try new drugs that may breach this protective area and cause the MRSA bacteria to be susceptible to certain antimicrobial drugs.
What is methicillin-resistant Staphylococcus aureus (MRSA)?
MRSA stands for methicillin-resistant Staphylococcus aureus (S. aureus) bacteria. This organism is known for causing skin infections in addition to many other types of infections. There are other designations in the scientific literature for these bacteria according to where the bacteria are acquired by patients, such as community-acquired MRSA (also termed CA-MRSA or CMRSA), hospital-acquired or health-care-acquired MRSA (also termed HA-MRSA or HMRSA), or epidemic MRSA (EMRSA). Statistical data suggest that as many as 19,000 people per year have died from MRSA in the U.S. Data supplied by the CDC in 2011 suggests this number has declined by about 54% from 2005 to 2011, in part, because of prevention practices at hospitals and home care. In addition, hospital deaths from MRSA infection have declined by about 9,000 per year from 2005-2011. However, the CDC recently estimated about 80,000 infections with 11,000 deaths occurred in 2011, but they suggest that a far greater number of minor infections occurred in both the community and in hospitals.
Although S. aureus has been causing infections (staph infections) probably as long as the human race has existed, MRSA has a relatively short history. MRSA was first noted in 1961, about two years after the antibiotic methicillin was initially used to treat S. aureus and other infectious bacteria. The resistance to methicillin was due to a penicillin-binding protein coded for by a mobile genetic element termed the methicillin-resistant gene (mecA). In recent years, the gene has continued to evolve so that many MRSA strains are currently resistant to several different antibiotics such as penicillin, oxacillin, and amoxicillin (Amoxil, Dispermox, Trimox). HA-MRSA are often also resistant to tetracycline (Sumycin), erythromycin (E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone), and clindamycin (Cleocin). In 2009, research showed that many antibiotic-resistant genes and toxins are bundled and transferred together to other bacteria, which speed the development of toxic and resistant strains of MRSA. S. aureus is sometimes termed a superbug because of its ability to be resistant to several antibiotics.
In addition, these organisms have been termed "flesh-eating bacteria" because of their occasional rapid spread and destruction of human skin. Additionally, a number of older (2004-2008) web and popular press articles are titled or include the erroneous term "MRSA virus." This is a misnomer that has confused many people; there is no contagious MRSA virus, and if readers examine these articles, they may realize the content is usually about MRSA bacteria.
Learn more about: oxacillin | Sumycin | Eryc | Ery-Tab | PCE | Pediazole
Unfortunately, MRSA strains of bacteria can be found worldwide. In general, healthy people with no cuts, abrasions, or breaks on their skin are at low risk for getting infected. However, the bacteria can be passed from person to person by direct contact with infected skin, mucus, or droplets spread by coughs in both adults and children. Indirect contact also can spread the bacteria; for example, touching items like towels, utensils, clothing, or other objects that have been in contact with an infected person can spread the bacteria to other uninfected individuals. Investigators estimate that about one out of every 100 people in the U.S. are colonized with MRSA (have the organisms in or on their body but not causing infection), and these individuals may transmit MRSA bacteria to others by the same methods listed above. Another term for people colonized with MRSA is "carrier" which means the person carries the organism in or on the body and may transfer the organism to another person who subsequently may become infected. A common place for carriers to harbor MRSA organisms is the nose.
What does a MRSA infection look like?
On the skin, MRSA infection may begin as a reddish rash with lesion(s) that looks like a pimple or small boil. Often it progresses to an open, inflamed area of skin (as pictured below) that may weep pus or drain other similar fluid. In some instances, it may appear as an abscess, a swollen, tender area, often with reddish skin covering. When the abscess is cut open or spontaneously bursts open, pus drains from the area.
What does a MRSA infection look like?What are the risk factors for MRSA infections?
People with higher risk of MRSA infection are those with obvious skin breaks (for example, patients with surgical or traumatic wounds or hospital patients with intravenous lines, burns, or skin ulcers) and people with depressed immune systems (infants, the elderly, or HIV-infected individuals) or those with chronic diseases (diabetes or cancer). People with pneumonia (lung infection) 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. Consequently, health-care workers and patient visitors should use disposable masks, gowns, and gloves when they enter the MRSA-infected patient's room. 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.
What are the signs and symptoms of a MRSA infection?
Most MRSA infections are skin infections that produce the following signs and symptoms:
Most of the above signs and symptoms represent the early stages of MRSA infections. One major problem with MRSA (and occasionally with other staph infections) 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. However, some infections can spread to or originate in areas like the lungs, ears, or sinuses. Some CA-MRSA and HA-MRSA infections become severe, and complications such as endocarditis, necrotizing fasciitis, osteomyelitis, sepsis, and death may occur.
How is a MRSA infection transmitted or spread?
MRSA infections are contagious from person to person; occasionally direct contact with a MRSA-infected person is not necessary because the bacteria can also be spread by people who touch materials or surfaces contaminated with MRSA organisms. 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 (people who are not infected but are colonized with the bacteria on their body) of MRSA. The second way is for people to physically contact MRSA on any objects such as door handles, floors, sinks, or towels that have been touched by a MRSA-infected person or carrier. Normal skin tissue in people usually does not allow MRSA infection to develop; however, if there are cuts, abrasions, or other skin flaws such as psoriasis (a chronic inflammatory skin disease with dry patches, redness, and scaly skin), MRSA may proliferate. Many otherwise healthy individuals, especially children and young adults, do not notice small skin imperfections or scrapes and may be lax in taking precautions about skin contacts. This is the likely reason MRSA outbreaks occur in diverse types of people such as school team players (like football players or wrestlers), dormitory residents, and armed-services personnel in constant close contact. A recent example of this spread of MRSA occurred in three NFL football players, all members of the same team, Tampa Bay. Three players got skin infections, and one had to undergo foot surgery to rid the player of recurrent MRSA infection.
How is a MRSA infection diagnosed?
Most doctors start with a complete history and physical exam of the patient to identify any skin changes that may be due to MRSA, especially if the patient or caretaker mentions a close association with a person who has been diagnosed with MRSA. A skin sample, sample of pus from a wound, or blood, urine, or biopsy material (tissue sample) is sent to a microbiology lab and cultured for S. aureus. If S. aureus is isolated (grown on a Petri plate), the bacteria are then exposed to different antibiotics, including methicillin. S. aureus bacteria that grow well when methicillin is in the culture are termed MRSA, and the patient is diagnosed as MRSA infected. The same procedure is done to determine if someone is a MRSA carrier (screening for a carrier), but sample skin or mucous membrane sites are only swabbed, not biopsied. These tests help distinguish MRSA infections from other skin changes that often appear initially similar to MRSA, such as spider bites and skin changes that occur with Lyme disease. These tests are very important; misidentification of a MRSA infection may cause the patient to be treated with other agents like dapsone (used for spider bites). This can result in progression of the MRSA infection and even other complications due to the dapsone.
In 2008, the U.S. Food and Drug Administration (FDA) approved a rapid blood test (StaphSR assay) that can detect the presence of MRSA genetic material in a blood sample in as little as two hours. The test is also able to determine whether the genetic material is from MRSA or from less dangerous forms of staph bacteria. The test (PCR based) is not recommended for use in monitoring treatment of MRSA infections and should not be used as the only basis for the diagnosis of a MRSA infection. In addition, there are new screening tests that report detecting or ruling out MRSA infections in about five hours.
How should caregivers treat MRSA patients at home?
The CDC states that healthy caregivers are unlikely to become infected while caring for MRSA patients at home if they do the following:
What is the treatment for a MRSA infection?
As stated by the U.S. Centers for Disease Control and Prevention (CDC):
Fortunately, many MRSA infections still can be treated by certain specific antibiotics (for example, vancomycin [Vancocin], linezolid [Zyvox], and others, often in combination with vancomycin). Most moderate to severe infections need to be treated by intravenous antibiotics, usually given in the hospital setting. Some CA-MRSA strains are susceptible to trimethoprim-sulfamethoxazole (Bactrim), doxycycline (Vibramycin), and clindamycin (Cleocin); although reports suggest clindamycin resistance is increasing rapidly. In addition, some strains are now resistant to vancomycin. In 2011, researchers developed a chemical change in the antibiotic vancomycin that rendered vancomycin-resistant MRSA susceptible to the drug. It is not available commercially, but this discovery, along with ongoing research, is important because it may expand treatment possibilities for MRSA and other drug-resistant bacteria such as VRE (vancomycin-resistant enterococci). Another drug, Teflaro, has been approved for treatment by the FDA for MRSA infections.
Learn more about: Zyvox | Bactrim | Vibramycin
A good medical practice is to determine, by microbiological techniques done in a lab, which antibiotic(s) can kill the MRSA and use it alone or, more often, in combination with additional antibiotics to treat the infected patient. Since resistance can change quickly, antibiotic treatments may need to change also. Many people think they are "cured" after a few antibiotic doses and stop taking the medicine. This is a bad decision because the MRSA may still be viable in or on the person and thus is capable of reinfecting the person or others. Also, the surviving MRSA may be exposed to low antibiotic doses when the medicine is stopped too soon; this low dose may allow MRSA enough time to become resistant to the medicine. Consequently, MRSA patients (in fact, all patients) treated with appropriate antibiotics should take the entire course of the antibiotic as directed by their doctor. A note of caution is that, in the last few years, there have been reports of a new strain of MRSA that is resistant to vancomycin (VRSA or vancomycin-resistant S. aureus) and other antibiotics. Currently, VRSA is detected more often than a few years ago, but if it becomes widespread, it may be the next superbug.
The CDC recommends clinicians use the 2011 guidelines published by the Infectious Diseases Society of America (IDSA) that details treatments. The 38-page set of guidelines can be found at http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/MRSA.pdf.
Research is ongoing; in 2013, new discoveries about the bacterial cell wall configuration are leading researchers to try new drugs that may breach this protective area and cause the MRSA bacteria to be susceptible to certain antimicrobial drugs.
What is the prognosis (outlook) of a MRSA infection?
The prognosis of MRSA infections depends on the severity of the infection when first diagnosed, the overall condition of the patient, and the patient's response to appropriate treatments and supportive treatments, if needed. Mild to moderate skin infections (boils, small abscesses) in patients with otherwise good health almost always have a good prognosis with full recovery if treated appropriately. However, patients with more severe disease and/or additional health problems (for example, diabetes, immunocompromised status, infected trauma wound) or those who acquire MRSA in an ICU or hospital while recovering from another problem have prognoses that vary from good to poor. MRSA pneumonia or sepsis has a death rate of about 20%. In addition, patients that are treated and do well still have a high risk of recurrent infection that may vary from 20%-40%. In addition, treatment with multiple antibiotics can lead to other infections such as pseudomembranous colitis caused by Clostridium difficile.
How can people prevent a MRSA infection?
Not making direct contact with skin, clothing, and any items that come in contact with either MRSA patients or MRSA carriers is the best way to avoid MRSA infection. In many instances, this situation is simply not practical because such infected individuals or carriers are not immediately identifiable. What people can do is to treat and cover (for example, antiseptic cream and a Band-Aid) any skin breaks or wounds and use excellent hygiene practices (for example, hand washing with soap after personal contact or toilet use, washing clothes that potentially came in contact with MRSA patients or carriers, and using disposable items when treating MRSA patients). Also available at most stores are antiseptic solutions and wipes to both clean hands and surfaces that may contact MRSA. These measures help control the spread of MRSA.
Pregnant women need to consult with their doctors if they are infected with or are carriers of MRSA. Although MRSA is not transmitted to infants by breastfeeding, there are a few reports that infants can be infected by their mothers who have MRSA, but this seems to be an infrequent situation. Some pregnant MRSA carriers have been successfully treated with the antibiotic mupirocin cream (Bactroban).
In 2007, the first incidence of MRSA in a pet was recorded. Although relatively rare, MRSA can be transferred between pets and humans. MRSA has been documented in dogs, cats, and horses but may be found in other animals in the future. Care and treatments are similar to those in humans, but a veterinarian should be consulted on all potential cases.
MRSA has been isolated from the environment (for example, beach sand and water), but there is no good documentation that people have become infected from these sources. Most authors suggest prevention methods should consist of a good soap and water shower after visiting the beach.
The CDC does not recommend (2012 guidelines) general screening of patients for MRSA. However, the CDC does recommend that high-risk patients who are being admitted to the hospital be screened for MRSA and then, if positive for MRSA, follow infection-control guidelines during the hospital stay. A recent study showed that the number of infections with both HA-MRSA and CA-MRSA has dropped since 2005-2008, and authorities speculate that such drops are due to infection-control measures in hospitals and better home-care measures (listed below).
Source: http://www.rxlist.com
Source: http://www.rxlist.com
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