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Running Head: METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
The Epidemiology of Methicillin-Resistant Staphylococcus Aureus
Stefanie Varno
Concordia University
24 July 2013
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Running Head: METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
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Staphylococcus Aureus (“staph”) is a type of bacteria often found on the skin or in the
nose of healthy individuals. Nearly 30% of people have “staph” and do not have any symptoms
(Center for Disease Control and Prevention Frequently Asked Questions, 2008). It is a type of
bacteria that is normally harmless and is easily spread through contact (Nordqvist, 2009).
Methicillin-Resistant Staphylococcus Aureus (MRSA) is a staph that is resistant to frequently
used drugs in the penicillin family and certain cephalosporins. Table 1 below depicts CA- and
HA-MRSA drug resistance. MRSA used to predominately be a problem in the hospital setting
(Hospital Acquired-Methicillin-Resistant Staphylococcus Aureus HA-MRSA) but recently has
become a community-acquired (CA-MRSA) problem and affects apparently healthy individuals.
MRSA can cause different types of infection to include asymptomatic colonization where
the bacteria is not directly affecting the host, but could flare up or easily spread to other people
(Pal, Julie). Usually MRSA causes minor skin infections that appear as painful and reddish
colored sores or boils (Center for Disease Control and Prevention, 2010) (Photos of MRSA can
Running Head: METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
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be seen at the following website: http://www.cdc.gov/mrsa/symptoms/index.html). Recognizing
the signs and early treatment are key factors in preventing an infection from becoming serious or
rapidly spreading. Generally MRSA looks like a bug bite at first, it typically has some drainage
and occurs near wounds or areas of hair growth (Center for Disease Control and Prevention,
2010). Staphylococcus Aureus is the most common cause of wound infection due to an
accidental injury or surgery (Pal, Julie). Other factors, such as diabetes, can increase the risk of
MRSA due to poor blood supply and skin damage allowing MRSA to easily enter the body with
little to no resistance.
MRSA cannot only affect the skin, causing sores and open wounds; it can also cause
superficial ulcers, bacteraemia (blood infections), deep abscesses and lung infections (Pal, Julie).
Most of the above listed ailments are very serious and can be prevented if proper precautions are
taken. Practicing proper personal hygiene and equipment sanitation are necessity in decreasing
the severity and spread of MRSA. Hand washing is not only the single greatest method of
prevention but it is very simple. The problem with hand washing is that “there is no technology
that will ensure that health care workers disinfect their hands…” (Noskin, 2008). Although
overall rates of compliance are unacceptably low, that may be changing soon due to the financial
impact. Medicare and Medicaid no longer pay for certain conditions that were not present upon
admission to the hospital. Hopefully with this change the number of patients affected will
decrease by hospital administration putting more emphasis on the importance of hand washing.
According to the CDC from 2005-2008 invasive infections of MRSA fell 28% for in
hospital-acquired cases, yet the total number of infections rose drastically from 21/1000 to
42/1000 (Fung, 2012). Today the total number of people checking into the hospital to be treated
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for MRSA is greater than the number checking in for HIV and influenza combined (Fung, 2012).
MRSA is becoming a superbug, it is difficult to treat yet easily spread.
“The increase in MRSA infections most likely reflects the growing impact of medical
interventions, devices, older age, and comorbidities of patients. Antibiotic use and overuse
probably also contribute to the emergence of resistance.” (Boucher and Corey, 2008). According
to a study by Rupak Datta and Susan S Huang (2008); “Individuals who are known to have
harbored MRSA for > 1 year are at high risk for subsequent MRSA morbidity and mortality and
should be considered to be targets for intervention…” In 2008 it was estimated that 94,000
people developed a serious MRSA infection, which lead to 18,650 fatalities (Noskin, 2008). It is
calculated that 15% of these cases occurred with no connection to a healthcare facility (Noskin,
2008). In Table 2 below it shows the number of deaths for different diseases in different years
with MRSA being the leading cause (Boucher and Corey, 2008).
Table 2
Annual death rates in the United States for selected infectious diseases.
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MRSA was first recognized about 50 years ago and quickly became a problem, which it
remains today (Noskin, 2008). In the hospital setting MRSA is found in the greatest quantity in
the Intensive Care Units (ICU). Since 1995 the rate of MRSA in the ICU has increased more
than 20%. But the hospital is not the only venue for MRSA; in the community person-to-person
spread of MRSA is reported regularly. “Several factors have been shown to predict disease (table
3). Outbreaks have been reported among men having sex with men, medically underserved
individuals, military recruits, prison inmates, athletes, postpartum women, individuals who use
intravenous drugs, and heterosexual couples (razors were implicated in 2 of 3 cases of
heterosexually transmitted community-associated MRSA” (Boucher & Corey, 2008).
Table 3
Epidemiologic risk factors for infection with community-associated methicillin-resistant
Staphylococcus aureus (MRSA).
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When it comes to who is at risk for MRSA everyone needs to be cautious and take
preventative measures. “Geographic variation in the United States has been observed, with more
MRSA infections seen in the South. Similarly, in Europe, considerable variation exists in the
incidence of MRSA, with only 0.5% in Iceland but 44% in Greece from 1999 to 2002.” (Boucher
and Corey, 2008). Studies have also observed that MRSA fluctuates geographically, outbreaks
have been reported from the U.S. to Saudi Arabia to New Zealand. A study in 2001-2002
revealed a disease incidence of 25.7/100,000 persons in Atlanta and 18/100,000 persons in
Baltimore (Boucher and Corey, 2008).
There are many risk factors for MRSA to include close contact with others, lack of hand
washing, unsterilized surgical tools, prolonged exposure in a health care facility, etc. Doctors
and nurses can even spread MRSA. “Sixty percent of doctor’s uniforms and 65% of nurses’ were
found to carry dangerous bacteria, including MRSA. Out of 75 nurses' uniforms that were tested,
the researchers detected the superbug in 21 of them, and in 6 out of 60 doctors' uniforms”
(Nordqvist, 2009). Hospitals are particularly dangerous when it comes to MRSA because they
provide not only a breeding ground for the bacteria, but also a multitude of susceptible patients.
Nordqvist (2009) gives several examples of concern for HA-MRSA:

Hospitals contain a large number of people with weakened immune systems who could
become infected with MRSA and develop unwanted symptoms

Many of the patients in a hospital have an intravenous drip or a catheter that creates a
"wound" through which MRSA can enter the body
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In some hospitals, people are in close proximity to each other, which increases the
chances of MRSA infecting patients. However, in others patients stay in separate rooms
which helps to lower this risk
Running Head: METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
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Hospitals offer many opportunities for Staphylococcus aureus bacteria to encounter a
wide range of antibiotics and, through genetic change and survival, develop resistance
to all of them.
Some specific risk factors for CA-MRSA include (Mayo Clinic):

Participating in contact sports where the bacteria can spread easily through cuts and
abrasions and skin-to-skin contact

Living in crowded or unsanitary conditions such as military training facilities, child care
centers and jails
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Men having sex with men
“MRSA infections can occur in any geographic location and anywhere on a person’s body
and can affect anyone (Center for Disease Control, 2010). It used to be that hospitals were the
primary culprits but that is no longer the case. The leading cause for MRSA is an open wound or
broken skin. MRSA does not discriminate, if the bacteria are present and there is an entry point
on the skin it will invade. Everyone needs to take necessary precautions such as hand washing
because not only is each individual at risk, but when they are infected they also put those around
them at risk.
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References
Boucher, Helen W. and Corey, Ralph G. (2008). Oxford Journal. Epidemiology of MethicillinResistant Staphylococcus Aureus. Retrieved from
http://cid.oxfordjournals.org/content/46/Supplement_5/S344.full
http://cid.oxfordjournals.org/content/46/Supplement_5/S344.full
Center for Disease Control and Prevention (2011). Methicillin-Resistant Staphylococcus Aureus.
Retrieved from http://www.cdc.gov/mrsa/
Datta, Rupak and Huang, Susan S. (2008). Journal of the Royal Society of Tropical Medicine
and Hygiene. Risk of Infection and Death due to Methicillin-Resistnat Staphylococcus
Aureus in Long Term Carriers. Retrieved from
http://cid.oxfordjournals.org/content/47/2/176.full
Fung, Brian (2012). The Atlantic. MRSA On the Rise: Infections Have Doubled in 5 Years.
Retrieved from http://www.theatlantic.com/health/archive/2012/07/mrsa-on-the-riseinfections-have-doubled-in-5-years/260495/
Mayo Clinic (date unk). MRSA Infection. Retrieved from http://www.mayoclinic.org/mrsa/risksfactors.html
Nordqvist, Christian (2009). What is MRSA? Why is MRSA a Concern? How is MRSA
Treated? Retreived from http://www.medicalnewstoday.com/articles/10634.php
Noskin, Gary A. (2008). Methicillin-Resistant Staphylococcus Aureus. Retrieved from
http://www.webmm.ahrq.gov/perspective.aspx?perspectiveID=57
Pal, Julie (date unk). Methicillin Resistant Staphylococcus Aureus (MRSA). Retrieved from
http://www.slideshare.net/jsna/mrsa-1163155