Wednesday, March 29, 2017

MRSA, An Increasingly Common Super Bug


By Terence Chu, M.D.
March, 2008

The contents of this web site are provided as an informational tool. This is not intended to replace medical advice or care administered by a healthcare professional. Common sense should always be used when referencing this site. If, at any time, you feel your child is experiencing a medical emergency, call 911 immediately.

Over the last several years the popular press has talked about the potential for “super bugs” or resistant bacteria to develop. These resistant bacteria occur when antibiotics are used because some of the bacteria that are not killed by the antibiotics mutate to develop resistance against the antibiotic. Well, one of the super bugs is here and quite alive in Orange County. This pesky little critter is called Community Acquired – MRSA (CA-MRSA). MRSA stands for methicillin resistant Staphylococcus aureus. Staphylococcus aureus is a bacterium that causes mainly skin and soft tissue infections but also causes bone and joint infections and pneumonias as well as other infections if given the chance. S. aureus was originally sensitive to (or able to be killed by) regular penicillin. However by 1960 the vast majority of S. aureus was resistant to penicillin. Luckily new antibiotics that could combat this resistance became available and we could still treat S. aureus infections. However, hospitals eventually developed Hospital Acquired – MRSA (HA-MRSA) which were resistant to most antibiotics including antibiotics like methicillin, nafcillin, Keflex, and Augmentin (to name a few that you may have heard of). Luckily, this was mainly only a problem in hospitals and nursing homes. Patients who were hospitalized for extended periods of time and/or who were on several different antibiotic courses were more likely to become colonized with HA-MRSA. Then ultimately they could develop an infection from the HA-MRSA when the bacteria were given the opportunity (like a skin infection from a break in the skin or pneumonia in a patient on a ventilator). These bacteria were difficult to treat but most of the time could be treated by an intravenous antibiotic called vancomycin.

Unfortunately in the last 10 years, the super bug we call CA-MRSA has emerged in the community. Like the old hospital super bugs these bacteria are resistant to most antibiotics however they are often sensitive to some antibiotics that we can give orally if a patient is well enough to be treated as an outpatient. The most common diseases we see from these bacteria are mainly skin and soft tissue infections. We are seeing a lot of impetigo and folliculitis (superficial skin infections) and a lot of boils (deeper skin infections). The boils often look like spider bites but they have nothing to do with spiders. Occasionally we have patients that develop more serious CA-MRSA infections such as pneumonias or bone infections. Unfortunately these infections can be severe with much tissue damage and often tend to occur again and again because the patient keeps getting recolonized with the bacteria. The infections are also becoming more difficult to treat as the bacteria become resistant to more antibiotics.

Why has this CA-MRSA emerged? The answer is simple: overuse of antibiotics. The more we use antibiotics, the more resistant bacteria we develop. Doctors over prescribe antibiotics and parents/patients request antibiotics when the antibiotics are not needed. So the charge for us all in our communities is to use antibiotics when a bacterial infection is present and antibiotics are felt necessary to help eliminate the infection, but to avoid antibiotics if we have just a viral infection (like colds) or a very local bacterial infection that may resolve with just local care (like with warm compresses, cleaning and drainage). So doctors need to better educate their patients’ families and parents need to ask themselves and the doctor if antibiotics are likely to help when their child is sick.