Can A New Molecular Test Enhance MRSA Detection?

Pages: 8 - 14
By Brian McCurdy, Associate Editor

Given the substantial rates of methicillin resistant Staphylococcus aureus (MRSA) infection in hospitals, early detection is vital to ensure timely and appropriate treatment. A new molecular test may significantly decrease the amount of time it takes to detect MRSA and possibly reduce transmission of the bacteria, according to the authors of a new study. Researchers who conducted the two-year study, recently published in Critical Care, evaluated over 1,000 patients who had been admitted for longer than 24 hours to a medical intensive care unit (ICU) or surgical ICU. Authors of the study used the quick, multiplex immunocapture-coupled PCR (qMRSA) test to identify MRSA in the DNA on patient swabs. The median time between admission to the ICU and the notification of MRSA colonization decreased with the qMRSA test from 87 to 21 hours in the surgical ICU, compared with historical culture results, according to the study. Researchers say the quicker testing saved 1,227 preemptive hours of isolation for the 245 patients who were negative for MRSA. In addition, the study says the notification time in the medical ICU decreased from 106 to 23 hours. Furthermore, the on-admission screening identified the prevalence of MRSA to be 6.7 percent in the ICU patients, notes the study. Without the qMRSA test, researchers say hospital clinicians would have missed MRSA in 55 carriers. The on-admission screening and preemptive isolation led to a decrease in MRSA infections acquired in the medical ICU but did not affect the infections acquired in the surgical ICU, according to the study. What Are The Implications Of The Test? David G. Armstrong, DPM, MSc, PhD, who is “very familiar” with the promise of the qMRSA test, feels the testing, once perfected and disseminated, would permit quicker screening of MRSA and clinicians would be able to isolate infected patients more quickly. While the test would not immediately impact MRSA rates, it would give clinicians the capability of narrowing the spectrum of their antibiotic regimen more quickly, notes Dr. Armstrong, a Professor of Surgery, Chair of Research and Assistant Dean at the William M. Scholl College of Podiatric Medicine at the Rosalind Franklin University of Medicine in Chicago. Accordingly, he says practitioners would be less likely to use anti-MRSA drugs inappropriately. Benjamin A. Lipsky, MD, says the new test could potentially reduce MRSA transmission. “If the test quickly identified colonized/ infected patients, were safe and reasonably priced, and positive cultures resulted in effective MRSA eradication, it might reduce MRSA transmission among patients and between hospital and community,” says Dr. Lipsky, a Professor of Medicine at the University of Washington School of Medicine. While the testing appears helpful in the earlier identification of MRSA, Dr. Lipsky would prefer to see the study replicated in other institutions and for the comparator to be standard culture rather than historical controls. As he notes, the efficacy of cohorting patients infected or colonized with MRSA (or other epidemiologically significant organisms) remains unclear and the results may depend on the background prevalence of MRSA in a particular hospital. Dr. Armstrong feels the testing would be practical in a hospital or VA setting. However, Dr. Lipsky says the practicality of such testing in those settings depends on the validated accuracy and cost of the testing. As he points out, once a hospital’s prevalence of methicillin resistance among S. aureus isolates reaches a certain threshold, perhaps 30 percent, it is difficult to eradicate the MRSA from the center. BMS Revises Prescribing Data For Gatifloxacin By Brian McCurdy, Associate Editor Following reports that gatifloxacin (Tequin) may not be safe for use in patients with diabetes, the drug’s manufacturer, Bristol-Myers Squibb, has revised the drug’s prescribing information. Accordingly, gatifloxacin is now contraindicated in diabetic patients due to serious reports of hypoglycemia and hyperglycemia. Tequin is a newer generation quinolone with an FDA indication for uncomplicated skin and skin structure infections. A recent study in Clinical Infectious Diseases documented the rates of glucose homeostasis abnormality (GHA) adverse event reports (AERs) of gatifloxacin as compared to fellow quinolones levofloxacin, ciprofloxacin and moxifloxacin. All four drugs were responsible for a total of 568 GHA AERs in the United States between 1997 and 2003, according to the study. Of those 568 adverse events, researchers note gatifloxacin was responsible for 453, or 80 percent, including 17 fatal GHA AERs. As the study notes, patients who had GHA AERs were more likely older and being treated for diabetes. Researchers recommended that practitioners use alternatives to gatifloxacin in patients with diabetes. Gatifloxacin’s effect on glucose homeostasis may not be limited to patients with diabetes. A case study in the Annals of Pharmacotherapy examined a non-diabetic patient with progressive renal dysfunction, who was treated for severe hyperglycemia. On day nine of a 10-day course of gatifloxacin 200 mg/day, doctors discovered her blood glucose was 1121 mg/dL, and accordingly discontinued her gatifloxacin regimen, notes the case study. Sifting Through Alternative Antibiotics For Diabetic Foot Infections What alternatives to gatifloxacin are feasible for diabetic patients with lower extremity infections? Mark Kosinski, DPM, cites levofloxacin (Levaquin, Ortho-McNeil) and moxifloxacin (Avelox, Schering-Plough). While both have been reported to cause GHA AERs, Dr. Kosinski says these are “rare,” a finding supported by the Clinical Infectious Diseases study. Dr. Kosinski describes levofloxacin as “the workhorse drug of its class,” with an FDA indication for uncomplicated and complicated skin and skin structure infections. Levofloxacin has better activity than ciprofloxacin against Staphylococcus aureus, according to Dr. Kosinski, a Professor in the Department of Medicine at the New York College of Podiatric Medicine. Moxifloxacin recently received an indication for complicated skin and skin structure infections and has good activity against anaerobes such as B. fragilis, unlike levofloxacin, says Dr. Kosinski, a member of the Infectious Diseases Society of America. “Quinolones are running the risk of becoming an overused class of antibiotic with an increasing incidence of resistance being reported,” says Dr. Kosinski, adding that gatifloxacin is not the first quinolone to be associated with an unacceptably high rate of side effects. He says temafloxacin, grepafloxacin and trovafloxacin have been withdrawn or restricted because of adverse events. DPMs Gain Access To Medication Histories Provided By Pharmacies By Brian McCurdy, Associate Editor Physicians and their patients may gain easier access to medication histories, thanks to an emerging program by a company that provides electronic prescribing services. The plan by SureScripts is to garner patients’ medication histories from pharmacies. The company will also collaborate with doctors to make these medication histories available to patients. Doctors will be able to access a view of the patient’s medication history across all prescribers and SureScripts notes that physicians will get a complete view of current and past medications. With the system, DPMs will have a consistent view of the pharmacy’s instructions that accompany the prescription as well as data on patient allergies and the dispensation date of the medication, according to SureScripts. The company uses the software Certified Solutions Provider. What advantages can podiatrists gain from the program? Steven Peltz, CHBC, says estimates show that many negative drug interactions occur because the prescribing doctor may not know all the drugs the patient is taking. Accordingly, he says the plan will make physicians more aware of the medication history to alert them to potential drug-drug interactions. “Many patients travel around the country and may have more than one primary care physician. This will help all of the patient's doctors see what every other doctor has prescribed and confirm that all prescriptions are consistent,” says Peltz, the President of Peltz Management and Consulting Services. In addition, Peltz notes that with all the new drugs on the market, it may be difficult for DPMs to stay on top of all the potential side effects and he feels this system will help facilitate appropriate prescription writing. Since some pharmacists cannot read a doctor’s handwriting, he feels another advantage of the SureScripts plan is its elimination of the prescription pad and the correct and rapid transmit of information. What about privacy concerns? SureScripts notes that the process will be guided by both HIPAA regulations and state privacy rules, and will follow rigorous processes for authentication and confidentiality. Peltz says privacy is always a concern and while the company has made assurances, the project is ongoing. SureScripts says the pharmacies participating in the project include Ahold (Giant and Stop & Shop), Albertsons (Sav-On and Osco), Brooks-Eckerd, CVS, Duane Reed, Kerr Drug, Longs Drugs, Rite Aid, Safeway and Walgreens. Study Finds Increased Risk Factors For Diabetes Among Middle School Students By Brian McCurdy, Associate Editor Not only is diabetes prevalence on the rise in the general population, a new study indicates that children have an array of alarming risk factors for developing type 2 diabetes. The study, which was recently published in Diabetes Care, examined blood glucose drawn from 1,740 eighth-grade students from 12 schools. Many students exhibited risk factors for diabetes. These risk factors included impaired fasting glucose of 100 mg/dl in 40.5 percent of students and a fasting insulin value of 30 µU/ml in 36.2 percent of the students, according to the study. Researchers also noted that 49 percent of the students in the study had a body mass index (BMI) in the 85th percentile. Fasting glucose and fasting insulin values increased in accordance with higher BMI, notes the study. Researchers found fasting glucose was highest in Hispanic and Native American students. Kathleen Satterfield, DPM, attributes the increased prevalence of risk factors for diabetes in children to sedentary lifestyles, diet and genetic predisposition. For the Hispanic and Native American children with a higher prevalence, she calls their genetic predisposition an “unfair one-two punch.” For Mexican children in Texas, Dr. Satterfield says genetic factors are sometimes combined with the poverty that leads to poor dietary options. Dr. Satterfield notes that foods that are available for these kids are full of carbohydrates and fat while few fresh fruits or vegetables are available. “In San Antonio, it is the delicious but deadly diet of pure carbs—tortillas, flour or corn filled with beans, cheese, pork and all cooked in lard. It may be delicious but this is why we see kids in the first grade who weigh 100 pounds and already have type 2 diabetes,” posits Dr. Satterfield, a Clinical Associate Professor at the University of Texas Health Science Center at San Antonio. What Can Schools Do To Prevent Diabetes? Dr. Satterfield recalls that Robert Trevino, MD, discovered many inner city elementary school children in San Antonio who already had type 2 diabetes or its precursor, impaired glucose tolerance. She says Dr. Trevino began an educational program in which kids earned points by exhibiting good habits, such as exercise and health knowledge, and then could “spend” points on items like toys, clothes or school supplies. In her own childhood, Dr. Satterfield recalls the days before TV remote controls when kids had to walk across the room to change the channel. “There was no computer to entice us to spend hours surfing the Internet or playing games,” she recalls. “We had physical education classes. We also did not have vending machines in school. We did not have elevators in our schools. We walked to school.” Dr. Satterfield notes that Lawrence Harkless, DPM, is committed to changing the attitude in schools in Texas. Most schools in the state had eliminated physical education, calling it expendable. She says Dr. Harkless, as the Chairman of the Texas Diabetes Council, has made it his mission to get kids moving again. Dr. Satterfield feels kids could get healthier if they were motivated to exercise or participate in sports, or make healthy dietary choices. “Sure, we all go for the Coke and HoHos if given the choice but we have to be shown that maybe a Diet Coke and dried fruit are not so bad either,” she says. In Brief A track on pediatrics will be one of the featured events of the Midwest Podiatry Conference, which will be held at the end of this month in Chicago. The DuVries Memorial Pediatrics Track on April 27 will feature various pediatric topics, including abnormal gait, open and closed forefoot fractures, adductory deformities, the Ponseti Method, diagnostic ultrasound and skin conditions, according to conference organizers. Other sessions at the Midwest Podiatry Conference will focus on flatfoot correction, diabetes, wound care, practice management and forensic podiatry. For more information, call (312) 427-5810 or go to

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