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Introduction
Methillin-Resistant Staphylococcus Aureus (MRSA) infection is caused by staphylococcus bacteria that is resistant to beta-lactam antibiotics (e.g. penicillin, methicillin, and amoxicillin), which are normally used to treat staphylococcus infections. Studies have shown that about 40% of Staphylococcus aureus strains have developed resistance to methicillin (Durai, Ng, & Hoque, 2010). Most of the MRSA infections occur in people, who have been admitted in hospitals or other such healthcare settings as, for example, dialysis centers and nursing homes. In case of the development of infection in healthcare settings, it is also known as healthcare-associated (HA) MRSA infections. Usually, HA-MRSA infections are related to invasive procedures such as surgeries, and/or instruments such as artificial joints or intravenous tubing. Another form of MRSA infections is known as community-associated (CA) MRSA infection as it occurs in the normal community and in healthier people. CA-MRSA infection starts as a painful skin boil. Usually, it spreads as a result of skin-to-skin contact. Child care workers, high school wrestlers, and people living in crowded conditions have higher risk of getting the infection as compared to other people.
Etiology
Risk factors for HA-MRSA and CA-MRSA infections can be different as they appear in different settings. However, it has been found it is not essential for a person to transmit the infection as they can be transmitted with the help of people, who have been colonized and become carriers for infection (Jacobs, 2014).
Chances of developing HA-MRSA infection increase in hospitals as hospitalized patients are most vulnerable in this case. This infection can increasingly be occurred in elderly patients and patients having weakened immune system. Risk of developing the infection also increases in patients having a medical instrument such as intravenous line or catheter inserted in their body. Chances of getting the infection also increase in long-term healthcare facilities as, for example, nursing homes as these facilities have a close contact between patients and healthcare providers. Moreover, these facilities have patients having disturbed and declining immune systems (Jacobs, 2014).
Chances of developing CA-MRSA infection increase in those areas, where many people having high risk of cross-infection as, for example, poor people, schoolchildren, homeless young adults, athletes, military personnel, and day-care center personnel as well as clients. Athletes and sportsmen have high risk of infection, when they have close contact with other people while taking part in sports and contact in shower facilities and locker rooms (Jacobs, 2014).
Pathophysiological Processes
A MRSA infection is similar to Staphylococcus aureus infection, but in MRSA infection, bacteria is resistant to commonly used antibiotics. Generally, MRSA infection is related to higher mortality rates as compared to methicillin-sensitive Staphylococcus aureus infections. MRSA bacteremia have up to 40% of mortality rate. It has been found that resistance of Staphylococcus aureus to methicillin develops due to a protein known as penicillin-binding protein 2a (PBP2a). This protein is present in the membrane of MRSA (Durai et al., 2010), and produces by the mecA gene. This gene is component of a bigger Staphylococcus cassette chromosome (SCC)mec gene pattern. It is due to this gene that is used to determine whether MRSA is healthcare-associated or community-associated (Jacobs, 2014).
Various proteins or toxins are produced by MRSA bacterium as, for example, α, β, γ, δ enterotoxin, and Panton-Valentine leukocidin. Panton-Valentine leukocidin results in necrotizing pneumonia and necrotizing cellulitis. CA-MRSA may result in secretion of peptides that can stimulate and lyse human neutrophils. These strains can cause infection in young children, and has the ability to spread easily. However, it can respond to non-β-lactam antibiotic treatment (Durai et al., 2010).
Clinical Manifestations & Complications
Signs and symptoms of MRSA infection are similar to those of staphylococcus infections. In MRSA infections, small red bumps appear resembling pimples, spider bites, or boils. The area of infection can become red, pus filled, swollen, warm to the touch, highly painful (extreme level of pain that is more than the pain for the sore), or a combination of these issues. MRSA skin infections can appear anywhere on any body part but they commonly appear on the back of the neck, groin, the legs, or buttocks. With the progress of infection, it can spread to other body parts from the original site and fever could develop. If the problem is not treated soon after the appearance of signs and symptoms, the infection can go deeper in body parts that may result in painful abscesses requiring surgical draining or subcutaneous tissue removal from the infected area. MRSA infection can also result in pneumonia, if it infects the lungs, resulting in shortness of breath, coughing, and fever in the patient (Jacobs, 2014).
Diagnostics
Various diagnostic tests can be performed to determine MRSA infection. These tests may include in-vitro culture on plates, polymerase chain reactions (PCRs), and cultures in specially developed liquid broths. According to experts, a PCR infection is the most efficient way of detecting MRSA infection but sometimes this diagnostic test can show no results, so cultures can also be used when the spread of MRSA infection can be harmful and lethal as, for example, those vulnerable patients, who are in an intensive care unit. Researchers have found that MRSA detection is maximum on nasal swabs, but some other researchers have found that nasal swabs, if taken alone, are not able to identify MRSA colonization in about 24% of colonized patients. On a further note, researchers have found that rectal and throat swabs are better than nasal swabs in detecting MRSA infection. Liquid broths are also efficient in the identification of MRSA infection but they are not most sensitive methods of detecting the infection. Liquid broths are often used in intensive care units, where rapid administration of proper antibiotics are required to save lives (Durai et al., 2010).
Affected Health Patterns with Specific Impact
One of the most important health patterns are susceptibility patterns of Staphylococcus aureus isolates. Nearly, 10% of Staphylococcus aureus are susceptible to penicillin in the U.S. Although many strains of Staphylococcus aureus are resistant to penicillin, they are susceptible to penicillinase-stable penicillins such as methicillin and oxacillin. Strains that are resistant to both methicillin and oxacillin (MRSA strains) are resistant to almost all β-lactam agents such as carbapenems and cephalosporins, but they may show susceptibility to the novel class of MRSA-active cephalosporins such as ceftaroline. It has been found that HA-MRSA strains are multiply resistant to many antimicrobial agents such as fluoroquinolones, erythromycin, and tetracycline, but CA-MRSA strains are resistant only to ß-lactam agents as well as erythromycin. Researchers have reported that since 1996, MRSA strains have been reported, which show either decreased susceptibility to vancomycin or complete resistance to vancomycin (Centers for Disease Control and Prevention, 2013).
These susceptibility patterns have shown that MRSA infections can affect bloodstream, heart, lungs, joints, bones, and sometimes brain. After affecting the lungs, they can result in pneumonia, thereby leading to the increased chances of lung failure. After affecting the bones, they may cause bones to become brittle. MRSA infection can affect cells resulting in cellular failure, thereby leading to organ failure. MRSA can also affect the healthy heart (NHS Choices, 2015). All these things show that the quality-of-life of patients is decreased.
References
Centers for Disease Control and Prevention. (2013). Methicillin-resistant Staphylococcus aureus (MRSA) Infections. Retrieved January 24, 2016, from http://www.cdc.gov/mrsa/lab/index.html
Durai, R., Ng, P. C., & Hoque, H. (2010). Methicillin-resistant Staphylococcus aureus: an update. AORN journal, 91(5), 599-609.
Jacobs, A. (2014). Hospital-acquired methicillin-resistant Staphylococcus aureus: status and trends. Radiologic technology, 85(6), 623-648.
NHS Choices. (2015). MRSA infection - Symptoms. Retrieved January 24, 2016, from http://www.nhs.uk/Conditions/MRSA/Pages/Symptoms.aspx
Tarzi, S., Kennedy, P., Stone, S., & Evans, M. (2001). Methicillin-resistant Staphylococcus aureus: psychological impact of hospitalization and isolation in an older adult population. J Hosp Infect, 49(4), 250-254. doi: 10.1053/jhin.2001.1098
