Community-Acquired MRSA’s Increasing Prevalence in Pediatric Patients

Once considered a hospital anomaly, community-acquired infections with drug-resistant strains of the bacterium Staphylococcus aureus now turn up regularly among children hospitalized in the intensive-care unit, according to research from the Johns Hopkins Children’s Center.

The Johns Hopkins Children’s team’s findings, to be published in the April issue of the journal Emerging Infectious Diseases, underscore the benefit of screening all patients upon hospital admission and weekly screening thereafter regardless of symptoms because MRSA can be spread easily to other patients on the unit.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a virulent subset of the bacterium and impervious to the most commonly used antibiotics. Most CA-MRSA causes skin and soft-tissue infections, but in ill people or in those with weakened immune systems, it can lead to invasive, sometimes fatal, infections.

In 2007, The Johns Hopkins Hospital began screening all patients upon admission and weekly thereafter until discharge. Some states have made patient screening mandatory but the protocols vary widely from hospital to hospital and from state to state.

“MRSA has become so widespread in the community, that it’s become nearly impossible to predict which patients harbor MRSA on their body,” says lead investigator Aaron Milstone, M.D., M.H.S., a pediatric infectious disease specialist at Hopkins Children’s.

“Point-of-admission screening in combination with other preventive steps, like isolating the patient and using contact precaution, can help curb the spread of dangerous bacterial infections to other vulnerable patients.”

The new Johns Hopkins study found that 6 percent of the 1,674 children admitted to the pediatric intensive-care unit (PICU) at Hopkins Children’s between 2007 and 2008 were colonized with MRSA, meaning they carried MRSA but did not have an active infection. Of the 72 children who tested positive for MRSA, 60 percent harbored the community-acquired strain and 75 percent of all MRSA carriers had no previous history or MRSA. MRSA was more common in younger children, 3 years old on average, and among African-American children. The reasons behind the age and racial disparities in MRSA colonization remain unclear, the investigators say. Patients with MRSA had longer hospital stays (eight days) than MRSA-free patients (five days) and longer PICU stays (three days) than non-colonized patients (two days).

Eight patients who were MRSA-free upon admission became colonized with MRSA while in the PICU. Of the eight, four developed clinical signs of infection, meaning that the other four would have never been identified as MRSA carriers if the hospital was not performing weekly screenings of all patients.

The research was funded in part by the National Institutes of Health, the Thomas Wilson Sanitarium for Children in Baltimore and by the Centers for Disease Control and Prevention.

Source: John Hopkins Medicine (March 26, 2010)

Bacterial Infections

Sometimes, Death Is Good….. For A Vicious Unicellular Microorganism

There are a variety of different types of foreign bacterial infections one can get from many different sources, yet some are more common than others. If they are not beneficial for your physiology, they all should die in order to restore your health.
Bacteria are a simple life form, yet are incredibly productive and efficient. As with other life forms, it exists to reproduce, and does so about every hour, and evolves and adapts to its environment as needed. To do this, it fully utilizes all available resources and energy to develop the protein that is essential for its survival, and bacteria have the ability to adapt as needed to assure this happens.
It needs exactly 7 genes to produce the essential ribosomes for this to occur. Any more or less genes than 7, the bacteria is not maximizing its efficiency to survive and reproduce. Amazing.
Strept infections are caused by what are called gram positive bacteria, and are unique that these bacteria grow in pairs. Staph bacterial invasions are gram positive as well, yet it is the MRSA, Methicillin Resistant Staff Aureous microbes of this type often are very difficult to treat normally when a patient suffers from their damage from being invaded by these bacteria. Another difficult situation is when a patient is infected by VRE, Vancomycin Resistant Enterococci, as well.
These MRSA and VRE pathogenic or disease causing bacteria are the ones that are the most clinically concerning for the health care provider.
Group A strep infections can cause diseases such as strep throat and pneumonia. Since there are several types of bacteria, a diagnostic test called a culture and sensitivity is usually performed to assure the correct antibiotic is selected for treatment, as the bacteria are identified with this method.
Typically, fluid from the area suspected of being infected is obtained from the patient suspected to have an infection and smeared on what is called a petrie dish. And then these dishes are incubated for 2 to 3 days. Gram positive bacteria stain during this process a dark violet or blue. Gram negative bacteria would be pink in color, and are capable of harm as well to a human being.
When the culture is complete, technology offers recommendations on the appropriate class or brand of antibiotic for this bacteria present in another person- presuming the bacteria will not be resistant to the antibiotic recommended, as this happens on occasion.
Usually, classes of antibiotics that are used to treat gram positive strep infections that are not VRE or MRSA are cephalosporins, macrolides, or general penicillins. If the microbe that is causing the infection is resistant to the antibiotic from such classes that are administered to the infected patient, particularly with methicillin and vancomycin, which is the case with VRE and MRSA bacteria, then there are other more aggressive antibiotics that will be chosen for this patient.
Such brands and types of antibiotics for MRSA and VRE bacteria include Zyvox, which has both IV and oral dosage options. There are also other antibiotics, such as Cubicin. However these antibiotics for antibiotic resistant bacteria are given usually due to infections that have progressed to a more serious nature within a patient infected in such a way.
Progressive medical conditions include sepsis, or blood infection, osteomyelitis, or bone infection, or Pneumonia, which is a serious lung infection. A hospital stay is normally required with such patients, as the last antibiotics mentioned for MRSA and VRE bacterial infections are given by IV administration initially for several days, if not several weeks.
There are numerous classes and types of antibiotics available, yet bacterial resistance to most of these antibiotics constantly remains serious concern for the health care provider, and the infected patient, with MRSA at the top of the list of concerns for the health care providers.
Dan Abshear
http://www.cdc.gov/ncidod/dhqp/ar_mrsa_spotlight_2006.html

Study Illuminates How Some Bacteria Survive Antibiotic Treatment

Some bacteria survive antibiotic treatment by activating resistance mechanisms when exposed to antibiotics, according to a recent study in the journal Molecular Cell. The results could lead to more effective antibiotics to treat a variety of infections.

“When patients are treated with antibiotics some pathogenic microbes can turn on the genes that protect them from the action of the drug,” said Alexander Mankin, professor and associate director of the University of Illinois at Chicago’s Center for Pharmaceutical Biotechnology and lead investigator of the study. “We studied how bacteria can feel the presence of erythromycin and activate production of the resistance genes.”

Sensing the presence of an antibiotic in the ribosomal tunnel, some bacteria have learned how to switch on genes that make them resistant to the drug. The phenomenon of inducible antibiotic expression was known decades ago, but the molecular mechanism was unknown. Mankin’s team of researchers include Nora Vazquez-Laslop, assistant professor in the Center for Pharmaceutical Biotechnology, and undergraduate student Celine Thum. assistant professor in the Center for Pharmaceutical Biotechnology, and undergraduate student Celine Thum.

“Combining biochemical data with the knowledge of the structure of the ribosome tunnel, we were able to identify some of the key molecular players involved in the induction mechanism,” said Vazquez-Laslop. “We only researched response to erythromycin-like drugs because the majority of the genetics were already known,” she said. “There may be other antibiotics and resistance genes in pathogenic bacteria regulated by this same mechanism. This is just the beginning.”

Source: Molecular Cell, April 24, 2008

Infection Expert Warns That MRSA May Be Unstoppable

Dr. Ron Najafi, CEO of NovaBay, describes MRSA (methicillin-resistant Staphylococcus aureus) as a slow-moving hurricane. "Once the ‘superbug’ hits a community or hospital," asks Dr. Najafi, "are populations ready to deal with it?"

His comment was prompted by the untimely death of college student Chris Steden to the disease, which infects 90,000 Americans in our hospitals every year, with 19,000 deaths reported annually.

The company is working on a compound, NVC-422, which may successfully fight many pathogens including MRSA. S. aureua breeds in the nose and on the skin. NovbaBay’s AgaNase formulation of NVC-422 for nasal applications, is an anti-infective, but not a conventional antibiotic. Topically applied to the lower nasal passage to eliminate colonization of S. aureus, including MRSA, AgaNase rapidly destroys a range of pathogens that include bacteria, yeast, and viruses.

Source: NobaBay Pharmaceuticals

Mathematical Model for Prescribing Antibiotics May Help Control Antibiotic Resistant Bacteria

In the United States some 100,000 people die every year because they become infected in hospital with a strain of antibiotic-resistant bacteria. To combat this problem, a sophisticated mathematical model has been developed that changes the way that antibiotics are prescribed and administered.

"We have developed the mathematical model in order to identify the key factors that contribute to this problem and to estimate the effectiveness of different types of preventative measures in typical hospital settings," said Vanderbilt mathematician Glenn F. Webb, who described the results at a presentation at the annual meeting of the American Association for the Advancement of Science on Feb. 17, 2008 in Boston, Massachusetts.

The most effective way to combat this growing problem, said Mr. Webb, was to minimize the use of antibiotics. It was no secret, he continued, that antibiotics were overused in hospitals. How to optimize its administration was a difficult issue. But the excessive use of antibiotics, which may benefit individual patients, was creating a serious problem for the general patient community.

The model, developed by an inter-disciplinary team of researchers, showed that in a hospital where antibiotic treatments were begun 3 days after diagnosis and continued for 18 days, the number of cross-infections by resistant bacteria increased and decreased but never disappeared completely. When antibiotic treatments started the day of diagnosis and continued for 8 days, however, the cross-infection rate fell to nearly zero within 20 days.

. The mathematical analysis reveals that the "optimal strategy" for controlling hospital epidemics is to start antibiotic treatments as soon as possible and administer the drugs for the shortest possible time. Beginning treatment as early as possible is the most effective in knocking down the population of the non-resistant bacteria that is causing a patient’s initial illness and minimizing the length of treatment shortens the length of time when each patient acts as a source of infection. "Our results point out an urgent need for more research into the issue of the best timing for the administration of antibiotics and how to reduce its misuse and overuse," said Webb.

The model was developed by an interdisciplinary team of researchers. In addition to Webb, the contributors are Erika M.C. D’Agata at Harvard University’s Beth Israel Deaconess Medical Center, Pierre Magal and Damien Olivier at the Université du Havre in France and Shigui Ruan at the University of Miami, Coral Gables. It is described in the paper "Modeling antibiotic resistance in hospitals: The impact of minimizing treatment duration" published in the Journal of Theoretical Biology.

Source: Journal of Theoretical Biology, December, 2007.