MRSA Topic

I couldn’t conceive of what it would be like for my daughter to lose her hands and the only other foot she has, as well, and that appears to be what is going to happen– Aimee Copeland’s Father

What is necrotizing fasciitis? The mention of this bacterial infection is often met with blank stares. However, those in the know, like Andy Copeland, will tell you of the horrific nature of the rare flesh-eating infection.  Copeland’s 24 year-old daughter, Aimee, contracted the infection a few days after suffering a nasty fall off of a homemade zip line on May 1. The accident resulted in a deep gash on her left calf which required nearly two dozen staples.

Three days later, Aimee began to complain of severe pain in her leg and was rushed back to the emergency room. Aimee was quickly diagnosed with necrotizing fasciitis caused by Aeromonas hydrophila, bacteria commonly found in brackish waters, and was flown to Augusta for surgery. Unable to treat her using antibiotics, Aimee’s physicians were forced to amputate her left foot. However, the bacteria continued to spread and her hands and remaining foot now require amputation. Read More

The community-acquired bacteria has evolved further, and is able to maintain a higher level of toxicity while also resisting treatment from antibiotics, making it a much larger problem- Journal of Infectious Diseases

The highly infectious strain, MRSA USA300 , is resistant to many front-line antibiotics and has now been discovered in public places, such as buses and trains. Though people can avoid direct contact with a sneeze or cough, Professor Thomas from the University of Birmingham highlights the possibility of becoming infected from touching surfaces.  In this way, every day settings and public surfaces act as viable means to contract an infection.  According to the Daily Mail, MRSA USA300 has been called “flesh-eating” due to its ability to lead to large skin boils, abscesses, blood poisoning and even fatal forms of pneumonia that destroy lung tissue.

The Daily Mail reports Dr. Ruth Massey of the Department of Biology and Biochemistry at the University of Bath warns people to take care in guarding against MRSA, especially strains that carry genes for Panton-Valentine leukocidin (PVL). This cytotoxin can destroy white blood cells and cause extensive tissue necrosis. According to Massey, more than a thousand PVL positive-community-acquired cases were reported in England last year. Of these, 1 in 5 were caused by the USA300 strain. Read More

At the very heart of the growing MRSA crisis in North America is the concept of bacterial resistance to antibiotic therapies. MRSA has found its way into the popular media, and people are becoming accustomed to reading stories about bacterial infections that can’t be treated with standard antibiotics. These stories, however, often gloss over or completely skip one important part – how did these bacteria become impervious to our best medicines in the first place? I’m not talking now about why or how antibiotic overuse and improper use has increased the number of resistant bacterial strains in recent years. Not that that isn’t important, but it’s something I’ve addressed in previous posts. No, I’m talking about how, down at the nitty-grittiest level, one little bacterial cell decides one day that it will no longer be affected by the very poison that was designed specifically to kill it?

I’m going to try not to get too technical in discussing a subject that is inherently technical and scientific in nature. Many clinicians and researchers dedicate entire careers to studying mechanisms of antibiotic resistance, and the detail of understanding now goes right down to the molecular level. Firstly, it must be understood that in many ways a bacterial cell looks and works differently than a cell from our bodies. Bacteria still have a genetic code contained within DNA, but in bacteria some of this DNA floats freely inside the cell, often in circular structures called plasmids. The interesting thing about bacteria is that they can pass plasmids (and thus, genetic code information) amongst each other through a process called plasmid transfer. This process allows certain traits that a single bacterial cell might possess to be shared with nearby bacteria quickly. A second key difference is that a single bacterium can divide into two new cells on its own, without the need for sexual reproduction between two parent cells.

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Question – What do you do when bacterial pathogens are developing resistance to available medicines faster than new therapies are being introduced to take their place?

Doesn’t sound like a sustainable situation, does it? Unfortunately it’s a very real situation in developed countries around the world. Strains of bacteria like methicillin-resistant Staphylococcus aureus (MRSA) have evolved in both hospital and community settings, and while MRSA is currently getting most of the press, the scary reality is that other strains are emerging that are even more deadly. Today, even most MRSA infections can be treated using a last-line antibiotic such as vancomycin. The problem arises when drugs like vancomycin are used more frequently because they are the only effective alternatives available. Only slightly less sure than death and taxes, is the relationship between use of an antibiotic and the subsequent ability of bacteria to develop and pass on resistance to that antibiotic. This is why original life-savers like first generation penicillins are no longer generally useful to us for treating modern day infections. It’s also why we have to be very careful about the use of vancomycin and our other last-line antibiotics. Read More

It is often that hospitals in a region share patients. Up until now, most studies on methicillin-resistant Staphylococcus aureus (MRSA) have focused on one hospital or a small group of hospitals. A recent study published in Infection Control and Hospital Epidemiology shows the impact of a MRSA outbreak on all hospitals in a large metropolitan county. It was found that an outbreak of MRSA at one hospital can impact other hospitals in the same area.

The study used extensive data collected from Orange County, California. Collectively, the hospitals in Orange County serve a population of 3.1 million people. An agent-based model was used to simulate patient movement throughout 29 Orange County hospitals. Valuable information was gained from the results of this study. It was found that increasing MRSA prevalence at a single hospital resulted in an up to 46% increase in relative MRSA prevalence at other hospitals.  This is cause for great concern as a MRSA outbreak at one hospital can affect all hospitals in the area. Hospitals therefore should not consider themselves an “island”, but part of an interconnected system.

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A few weeks back I wrote about the new (first) IDSA guidelines on MRSA treatment in hospitals. Not to be outdone, the Association for Professionals in Infection Control (APIC) has now released its second edition guidelines for MRSA treatment. APIC first put out guidelines on MRSA back in 2007, and with the recent explosion of MRSA-related research it was high time to take another look at new evidence and best practices in the field. Read More

In a previous post I touched on the infection risk associated with surgical procedures in hospitals, and the very real health threat posed by surgical site infections (SSI’s). I’d like to revisit SSI’s (and will likely do so again in the future), since they represent the largest subset of hospital-acquired infections and are particularly related to Staphylococcus aureus and MRSA.

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So how did you ring in the New Year….champagne?…fireworks?…resolutions? The Infectious Disease Society of America (IDSA) marked the occasion by releasing its very first official practice guidelines on treatment of MRSA infections in hospitals. These guidelines, published in the latest issue of the journal Clinical Infectious Diseases,¹ are the first from this organization to specifically address MRSA as opposed to more general infection control procedures. Read More

Staphylococcus aureus is a pretty versatile bug, meaning it dedicates a lot of its time and resources to developing ways to live happily on all kinds of tissue surfaces. As you’ve probably heard, we all have bacteria living all over on us and in us at all times. From the time you eat your first meal, you’ve got them throughout your digestive tract, and even earlier than that every inch of your skin is covered with bacterial cells. Fun fact – you have far, far more bacterial cells associated with you than you actually have of your own cells (by about 10 to 1)! Read More

Every year tens of millions of people undergo elective surgeries in U.S. hospitals (40 million in 2000 according to the National Office for Health Statistics). The term “elective” refers to a pre-planned, non emergency surgical procedure. Due to advances in modern medicine, over half of elective surgeries are now performed on an outpatient basis, meaning the patient is admitted and discharged in the same day, without the need for an overnight stay in the hospital. However, even with these surgical advances, there remains a significant risk of developing a surgical site infection (SSI) after an elective procedure. Read More