Recently the news has been full of information, some accurate and some not, about MRSA. The following article is in response to many phone inquiries recently received by Ontario County Public Health.

What exactly is Methicillin-Resistant Staphylococcus Aureus (MRSA)?

Let’s start with the abbreviations!

M = Methicillin

Methicillin is a penicillin-related antibiotic that was previously effective in the treatment of staph (staphylococci) infections.

R = Resistant
Antibiotic resistance is not a new phenomenon. Since the discovery of penicillin in the 1940’s, bacteria have been working hard to find ways to avoid being “killed” by antibiotics.

S = Staphlylococcus (“staph”)

Staphylococcus is the general name for the “family” of bacteria responsible for a wide variety of illnesses. Some forms of these bacteria live peacefully on the human body without causing disease. Others, however, can cause infections or produce toxins (by-products) that are very harmful to humans.

A = Aureus

Aureus denotes a specific sub-type of staphylococcus. Though there are many different sub-types, the most recognized is staph aureus.

MRSA therefore can be defined a “staph” infection (staphylococcus aureus) that is difficult to treat because the bacteria are resistant to penicillin-related antibiotics.

How does a person “catch” MRSA?

For years hospitals have been dealing with nosocomial (hospital-acquired) infections, including MRSA. Hospital-Acquired MRSA (HA-MRSA) is an “opportunistic” infection that occurs in a compromised host (a person who is already sick). 85% of all MRSA infections in the US in 2005 were associated with a healthcare setting.

When an individual is sick enough to be hospitalized or has undergone an invasive procedure or surgery his immune system is adversely affected. His ability to fight off infection is impaired and he is susceptible to invasion by bacteria that would usually be unable to harm him. HA-MRSA is very serious. Unfortunately because it does not respond well to antibiotics, it is implicated in thousands of deaths every year in the US.

Risks for HA-MRSA include recent hospitalization, surgery, residence in a long-term care facility, kidney dialysis, and the presence of invasive medical devices (central lines for chemotherapy, tracheotomy tubes, etc.).

Common HA-MRSA scenarios could include a cardiac bypass patient who develops a MRSA infection in his incision site in the days following his surgery or a cancer patient who develops a MRSA infection in his central line through which he receives his chemotherapy.

Recent reports have been about people who have “caught” MRSA in the community. Is this the same “super-bug” as HA-MRSA?
If hospital acquired disease was not bad enough, in 1993 a case of MRSA was diagnosed in a person who had no previous hospital exposure. It was suspected that this infection was acquired in the community (CA). Since that time there have been numerous reports of other cases usually involving the skin.

MRSAA community-acquired MRSA (CA-MRSA) infection is one that is contracted in the “community” (home, school, daycare, jail, playground, work, etc.), rather than in a healthcare setting. Though both types of MRSA are caused by staph aureus, there are significant differences in their genetic appearance (think CSI!). These subtle differences make CA-MRSA easier to transmit to otherwise healthy individuals than HA-MRSA. Fortunately, these differences also make CA-MRSA less resistant, thus easier to treat, than HA-MRSA. It is estimated that about 15% of all MRSA cases in the US in 2005 were acquired in the community.

CA-MRSA usually involves the skin. There is speculation that many cases of CA-MRSA have been misdiagnosed as spider bites in the past. Skin lesions can be small and resemble pimples or can enlarge and become boils or abscesses. Often times, these lesions require only incision and drainage by a physician. Deeper infections may require antimicrobial treatment. There are medications available that are effective in treating CA-MRSA. Unfortunately in rare instances, the bacteria can invade the bloodstream (bacteremia), lungs (pneumonia) deeper skin tissues (necrotizing faciitis) or internal organs. Invasive CA-MRSA is very serious and can be life-threatening. Invasive disease is a very rare complication.

Why am I hearing about so many new cases?

MRSA is not a New York State reportable disease; therefore laboratories, hospitals and private physicians are not required to notify the local health department when a case is identified. For this reason it is very difficult to determine just how many cases exist in the community. Without this baseline rate of illness it is difficult to know for sure if we are truly seeing a significant increase in the number of cases.

It seems that more cases are being identified, recently but is this due to an increase in cases, an increase in testing, or a little of both? As has been the case with other diseases over the years, when awareness is raised, more testing follows. When there is more testing, more disease is diagnosed. In the past an inflamed skin lesion may have been passed off as an infected insect bite without the benefit of physician exam or culture. With recent heightened awareness I suspect more testing has and will continue to be done, possibly inflating the number of new cases.

How do I protect my family and myself?

To understand transmission and thus the prevention of infection it is helpful to consider the “The Five C’s” of CA-MRSA. These are the things that increase an individual’s risk of becoming infected.

  • Crowding (jails, military, schools, etc.)
  • Contact (direct contact with an infected lesion)
  • Compromised skin (scrapes and abrasions provide a “portal of entry” for bacteria)
  • Contaminated surfaces and shared items (gym equipment, towels, razors, etc.)
  • Cleanliness (lack of hand washing, failure to cover wounds, etc.)
Based on “The Five C’s” it is easy to understand why CA-MRSA skin infections are popping up in football players, inmates, wrestlers, and school children.

CA-MRSA prevention measures include:

  • Frequent, thorough hand washing (60% alcohol hand sanitizers are also effective)
  • Covering of cuts or abrasions of the skin to prevent infection
  • Covering of infected lesions to prevent spread to others
  • Seeking medical advice for skin lesions that do not heal in a timely manner
  • Routine disinfection of surfaces that are apt to have been contaminated by secretions/excretions
  • Education of athletes about the dangers of sharing personal care items and the importance of showering after contact sports
  • Education of children about hygiene and disease prevention starting at an early age

Should a person with MRSA be excluded from school or the workplace?

Most individuals with MRSA do not need to be excluded from school or work, unless advised to by their physician. Exclusion should be reserved for two groups: those with wound drainage that cannot be covered and contained with a clean, dry bandage and those who cannot maintain good personal hygiene. Additionally, individuals with active infections should be excluded or refrain from activities where skin-to-skin contact is likely to occur if the infected area cannot be kept covered with a dry bandage during the activity.

Exclusions should be handled on an individual basis taking many factors into consideration: age of the individual (small children may be unpracticed at hygiene or may find it difficult to keep a “boo-boo” covered), mental status (an impaired individual may be unable to comply with instructions), athletes (an individual participating in sports involving skin-to-skin contact may find it difficult to maintain a dry bandage), etc.

What about surface cleaning?

Covering infections greatly reduces the risk of surfaces becoming contaminated with MRSA. Cleaning and disinfection with a detergent-based cleaner or EPA–registered disinfectant (for schools and businesses) should be performed on surfaces that are likely to come into contact with uncovered or poorly covered infection sites.

What is Ontario County Public Health doing about the recent reports of MRSA in the community?

Because MRSA is not a New York State reportable disease, Ontario County Public Health is not alerted when an individual in the community is diagnosed with MRSA. Public Health should be notified, however, about clusters of CA-MRSA: multiple family members, athletes from the same sports team, children who share a classroom, college students who share dorm rooms, etc. If these scenarios arise please contact us at (585) 396-4343. Personnel are available to partner with physicians, schools, coaches, etc. to assist with educational efforts and to explore additional strategies for disease prevention in these cases.

More information about MRSA can be found at: