chapter 9

Chapter 9Chapter 9

Question 6:Question 6:Last semester, several students at CCRI were hospitalized with Last semester, several students at CCRI were hospitalized with

potentially life-threatening MRSA infections. potentially life-threatening MRSA infections.

What is MRSA?What is MRSA?

How did this dangerous bacterial strain evolve? How did this dangerous bacterial strain evolve?

Explain.Explain.

Carl Tuoni Beth Miller

Silvio Penta

What is MRSA and its Signs and SymptomsWhat is MRSA and its Signs and Symptoms

Methicillin-resistant Staphylococcus aureus (MRSA) Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by Staphylococcus aureus bacteria, infection is caused by Staphylococcus aureus bacteria, often called "staph.” often called "staph.”

Staph or MRSA infections usually start as small red Staph or MRSA infections usually start as small red bumps that resemble pimples, boils or spider bites. bumps that resemble pimples, boils or spider bites. These can swiftly turn into deep, sore abscesses that These can swiftly turn into deep, sore abscesses that require surgical draining. Sometimes the bacteria require surgical draining. Sometimes the bacteria remain restricted to the skin. But they can also burrow remain restricted to the skin. But they can also burrow deep into the body, causing potentially life-threatening deep into the body, causing potentially life-threatening infections in bones, joints, surgical wounds, the infections in bones, joints, surgical wounds, the bloodstream, heart valves and lungs.bloodstream, heart valves and lungs.

Staph skin infections often start out as small red bumps (right) and then turn into deep abscesses (left.)

Photo courtesy: The Mayo Clinic

AdvancedAdvanced MRSA Infection MRSA Infection

In 2005, according to CDC reports more people died from MRSA than AIDS. Most of these infections were contracted

in a healthcare setting.

http://education-portal.com/articles/MRSA_Outbreak_Threatens_U.S._Schools.html

CausesCauses• MSRA is the result of decades of excessive and MSRA is the result of decades of excessive and

unnecessary antibiotic use unnecessary antibiotic use

• Antibiotics that have been prescribed for colds, Antibiotics that have been prescribed for colds, flu, and other viral infections that do not respond flu, and other viral infections that do not respond to these drugs to these drugs

• Antibiotics found in food and water, antibiotics Antibiotics found in food and water, antibiotics can be found in beef, pigs and chickenscan be found in beef, pigs and chickens

• Even antibiotics that are used correctly they can Even antibiotics that are used correctly they can contribute to the rise of drug-resistant bacteriacontribute to the rise of drug-resistant bacteria

http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=1http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=1

Some Common ExamplesSome Common Examples::

1) You have a sore throat and go to the dr. he gives you an 1) You have a sore throat and go to the dr. he gives you an antibiotic called Augmentin because it is strep throat. Even antibiotic called Augmentin because it is strep throat. Even though the dr. told you to finish all of the medication, you feel though the dr. told you to finish all of the medication, you feel better and stop taking it after 5 days.better and stop taking it after 5 days.

2) You have a sore throat again, you have had strep before and 2) You have a sore throat again, you have had strep before and still have about half of that bottle of Augmentin you did not still have about half of that bottle of Augmentin you did not finish last time. So you decide to take the other half. Only this finish last time. So you decide to take the other half. Only this time the medicine doesn’t work. You have created a strain of time the medicine doesn’t work. You have created a strain of strep at least in your own body, which can no longer be fought strep at least in your own body, which can no longer be fought with Augmentin. Had you finished the medicine the first time with Augmentin. Had you finished the medicine the first time not only would you not have gotten it again so soon, but if you not only would you not have gotten it again so soon, but if you did get it agian the Augmentin would have worked again.did get it agian the Augmentin would have worked again.

Discovery, History & EvolutionDiscovery, History & Evolution• First identified in 1961 in the UK, MRSA was referred to in the press as “the First identified in 1961 in the UK, MRSA was referred to in the press as “the

superbug” because it resisted the broad spectrum of beta lactin (a natural antibiotic superbug” because it resisted the broad spectrum of beta lactin (a natural antibiotic produced by fungi) derived antibiotics. produced by fungi) derived antibiotics.

• Through the process of natural selection, the more resistant mutants of the species Through the process of natural selection, the more resistant mutants of the species became more prevalent, as the drug vulnerable strain died.became more prevalent, as the drug vulnerable strain died.

There is no question that MRSA evolved in the hospital setting. No one knows There is no question that MRSA evolved in the hospital setting. No one knows for sure how MRSA evolved into the community known as CA-MRSA. It did for sure how MRSA evolved into the community known as CA-MRSA. It did not however derive from the hospital strain. The theory that makes the most not however derive from the hospital strain. The theory that makes the most sense is that due to the over use of antibiotics, a stronger, more resistant sense is that due to the over use of antibiotics, a stronger, more resistant bacteria evolved.bacteria evolved.

One Third of the population are One Third of the population are carrying the infection carrying the infection

• Normally found on the skin or in the nose of around Normally found on the skin or in the nose of around one third of the populationone third of the population

• People carrying staph are said to be colonized but People carrying staph are said to be colonized but not infected with MRSA not infected with MRSA

• Healthy people can be colonized with MRSA and Healthy people can be colonized with MRSA and have no ill effects, however they can pass the germ have no ill effects, however they can pass the germ to othersto others

http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=1

Staph is generally Staph is generally harmlessharmless

• Staph bacteria are generally harmless unless Staph bacteria are generally harmless unless they enter the body through a cutthey enter the body through a cut

• Only causes minor skin problems in healthy Only causes minor skin problems in healthy peoplepeople

• Staph infection may cause serious illness in Staph infection may cause serious illness in older adults, or people who are ill, or have older adults, or people who are ill, or have weakened immune systemsweakened immune systems

http://www.mayoclinic.com/health/mrsa/DS00735/http://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=1DSECTION=1

The “Super-bug Hype”The “Super-bug Hype”As serious as MRSA is, it has been around for a long time, look at the graph below and you will see that the incidence of the infection has not gone up much from 2001, yet from 2005-07 it was in the news much more than earlier in the decade. http://www.hpa.org.uk/cdr/images/2006/0606_mrsa.gif

Risk FactorsRisk Factors• Because hospital and community strains of Because hospital and community strains of

MRSA generally occur in different settings the MRSA generally occur in different settings the risk factors for the two strains differ risk factors for the two strains differ

Risk factors for (HA) MRSA Include Risk factors for (HA) MRSA Include • Current or recent hospitalization- Current or recent hospitalization- MRSA is MRSA is

a concern among hospitals where it can attack a concern among hospitals where it can attack those most vulnerable those most vulnerable

• Residing in a long term care facility- Residing in a long term care facility- MRSA MRSA is far more prevalent in these facilities than in is far more prevalent in these facilities than in hospitalshospitals

• Invasive devices- Invasive devices- People who are on dialysis, People who are on dialysis, are catheterized, have feeding tubes, or other are catheterized, have feeding tubes, or other invasive devices are at a higher riskinvasive devices are at a higher risk

• Recent antibiotic use Recent antibiotic use


Risk factors for community Risk factors for community acquired (CA) MRSAacquired (CA) MRSA

• Young Age- Young Age- CA-MRSA can be particularly CA-MRSA can be particularly dangerous in children often entering the body dangerous in children often entering the body through a cut or a scrape. Their immune through a cut or a scrape. Their immune system may not be fully developed system may not be fully developed

• Participating in contact sports- Participating in contact sports- the the bacteria spread easily throbacteria spread easily thro

• ugh cuts and abrasions and skin to skin ugh cuts and abrasions and skin to skin contact. contact.

• Sharing towels or athletic equipment- Sharing towels or athletic equipment- CA-CA-MRSA has spread among athletes sharing MRSA has spread among athletes sharing razors, towels, uniforms, or equipment razors, towels, uniforms, or equipment


• Having a weakened immune system- Having a weakened immune system- People with a weakened immune system are People with a weakened immune system are more likely to have severe CA-MRSA more likely to have severe CA-MRSA infections infections

• Living in crowded or unsanitary Living in crowded or unsanitary conditions- conditions- Outbreaks of CA-MRSA have Outbreaks of CA-MRSA have occurred in military training camps and in occurred in military training camps and in prisonsprisons

• Association with health care workers- Association with health care workers- People who are in close contact with health People who are in close contact with health care workers are at serious risk of infections.care workers are at serious risk of infections.


Prevention is the Best Prevention is the Best MedicineMedicine

http://www.cdc.gov

Avoid contactAvoid contact with the wounds or with the wounds or bandages of othersbandages of othersKeep personal items personal . Keep personal items personal . Avoid sharing towels, razors, clothing, Avoid sharing towels, razors, clothing, and athletic equipmentand athletic equipmentKeep wounds covered. Keep wounds covered. Keep cuts and Keep cuts and abrasions clean and covered with abrasions clean and covered with sterile dry bandages until they heal sterile dry bandages until they heal Shower after athletic games or Shower after athletic games or practices practices Sanitize linens Sanitize linens if you have a cut or if you have a cut or sore wash towels and bed linens in a sore wash towels and bed linens in a washing machine using hot water. washing machine using hot water. Wash gym and athletic clothes after Wash gym and athletic clothes after each wearingeach wearing

http://www.mayoclinic.com/health/mrsahttp://www.mayoclinic.com/health/mrsa/DS00735/DSECTION=1/DS00735/DSECTION=1

chapter 9

Documents