Research Paper on Methicillin-Resistant Staphylococcus Aureus (MRSA)

1 Introduction The methicillin-resistant Staphylococcus aureus (MRSA), also known as the “superbug,” is a source of major concern for public health. First reported in 1961, the disease is no longer a sole property of inpatients’ infections, but spreads rapidly in the community, underlying more deaths in the US than AIDS (Boyles) and shows increasing prevalence not only among people with weak immune system, but also among those who would otherwise be the healthiest among us, such as athletes, military personnel and school-age children (Fang). This paper will shed light on the nature of the disease, its etiology, its agents and the current ways of treatment and prevention.

2 History, Occurrence and Etiology

In its most simple sense, MRSA is a skin infection, whose early symptoms are an infected area on the skin that may look like a bump, pimple or a minor rash. As any Staphylococcus-induced (“staph”) infections, the surface of an infected skin is likely to be “red, swollen, painful, warm to the touch, full of pus or other drainage [and often] accompanied by a fever” (CDC).

When left untreated, staph bacteria can find a way into the body through open wounds, needles and any other element which penetrates the epithelium that protects us from the outside. After penetrating the body, a stage known as invasive MRSA, the staph enters the blood circulation, dissolve many white blood cells and may cause severe infections, primarily Bacteremia, Pneumonia, Cellulitis, Osteomyelitis, Endocarditis and Septic shock (Klevens et al., 1768).

MRSA was first reported in Britain in 1961, when researchers identified that Staphylococcus bacteria developed resistance to methicillin and cloxacillin, two powerful antibiotics from thr penicillin family that were used against them. The staph’s ability to genetically modify their responsiveness to antibiotics was made possible in hospital conditions, which are characterized by inpatients with weak immune systems, a plentiful of invasive medical procedures and numerous transfer opportunities (e.g. through instruments and the medical staff).

Community-associated MRSA, a subtype of staph with some distinct biomarkers, was first reported among injecting drug users and children since the 1980s. Based on 2005 prevalence and infections data of the Centers for Disease Control and Prevention (CDC), Klevens et al. (1763) estimated incidence rate of the disease in the US at about 31.8 per 100,000 inhabitants, with the highest rates among people above 65 years of age, males and blacks. Interestingly, Fang points out that about 20% of the hospital-onsets of MRSA is due to the community-associated staph, indicating a change in the infection trend – the community “imports” staph into hospitals instead of visa versa.

3 Description of the Microorganism

The microbiological underpinning of MRSA is a subtype of the Staphylococcus bacteria, which is about 0.6 µm in diameter and looks lives in groups that look like small masses of grapes, as implied by its name (Greek for “bunch of grapes”).

The Staphylococci genus is known for decades as a primary cause of skin infection. MRSA bacteria, however, have developed the ability to produce Penicillinase, a bacterial enzyme that neutralizes antibacterial properties of penicillin, and therefore are resistant to most types of antibiotics.

MRSA are not more virulent than other staphylococci. They are, however, much more dangerous because they do not respond to the mainstream of antibiotics, which are considered as safer and more effective than the hard line treatments offered to MRSA patients. A further threat in that matter is the prospective ability of the bacteria to continue modifying itself, especially in hospital environment, a situation that may turn the still remaining effective antibiotics obsolete.

4 Treatments for MRSA

MRSA is being transferred through direct skin contact, touching contaminated surfaces and through equipment such as towels and razors. Thus, the main preventive measures are early detection, proper bandaging of cuts and scrapes, avoiding sharing personal items and, most importantly, frequently washing the hands and using decontamination materials in hospitals (CDC).

Treatments in early onsets are based on draining the infected surface and usage of several types of antibiotics such as Rifampicin, Vancomycin and Teicoplanin, which are still effective against most penicillinase-producing bacteria (Fang). Most cases of the invasive phase will be treated in ICUs, often requiring a considerably long stay of inpatients and isolations. Finally, as reported by Klevens et al. (1766), the average MRSA-induced mortality rate among the general population is 6.3 per 100,000 (indicating about 20% rate among those infected), although this figure is much higher among weak populations such as HIV-positive patients and the elderly.

References

  • Boyles, Salynn. “More U.S. Deaths From MRSA Than AIDS.” WebMD. 16 Oct. 2007. 7 July 2009 http://www.webmd.com/news/20071016/more-us-deaths-from-mrsa-than-aids
  • Fang, Ferric. “MRSA – The Bug Stops Here.” Laboratory Medicine Ground Rounds. University of Washington. 19 Nov. 2008. 7 July 2009 http://www.researchchannel.org/prog/displayevent.aspx?fID=567&rID=28237
  • Klevens, Monina R., Morrison, Melissa A., Nadle, Joelle, et al. “Invasive Methicillin-Resistant Staphylococcus aureus Infections in the United States.” Journal of the American Medical Association 298.15 (2007): 1763-71.
  • National MRSA Education Initiative: Preventing MRSA Skin Infections. 11 Sept. 2008. Centers for Disease Control and Prevention (CDC). 7 July 2009 http://www.cdc.gov/mrsa/