Un estafilococo mortal puede sobrevivir dos meses en juguetes

Por Anthony J. Brown
NUEVA YORK (Reuters Health) - El "supergermen" mortal, resistente a los fármacos, Staphylococcus aureus resistente a la meticilina (SARM) puede sobrevivir por semanas o meses en los juguetes y en otros objetos inanimados, lo que eleva el riesgo de transmisión a la piel.
El SARM fue un gran problema en los hospitales, porque atacaba a los pacientes debilitados por una enfermedad. Pero brotes recientes en la comunidad en personas sanas generaron una nueva preocupación.
Estudios previos habían demostrado que el SARM puede permanecer en varios objetos del entorno, indicó a Reuters Health el autor principal del estudio, doctor Rishi Desai, de Childrens Hospital Los Angeles.
"Nuestro estudio va dos pasos más allá porque demuestra la cantidad exacta de la bacteria que se puede encontrar en el tiempo y que el supergermen no sólo sobrevive en el entorno, sino que se transmite a la piel durante períodos prolongados", agregó Desai.
"Los hallazgos principales fueron que el SARM en la comunidad puede sobrevivir y pasar a la piel durante dos meses cuando está en objetos plásticos, como el vinilo y los bloques plásticos de construcción que usan los niños", declaró.
Desai presentó los resultados en Interscience Conference on Antimicrobial Agents and Chemotherapy, esta semana, en San Francisco.
El equipo de Desai obtuvo varios objetos involucrados en brotes de SARM adquirido en la comunidad, los cortó en bloques de 2 x 2 centímetros cuadrados y los esterilizó.
Luego, colocó en cada objeto cantidades pequeñas de la cepa del SARM hallada en la comunidad. Los objetos permanecieron así durante distintos períodos. Cada tanto, el equipo presionó un trozo de piel de cerdo estéril sobre el objeto y analizó la presencia del supergermen.
El equipo halló que el SARM puede transmitirse durante períodos más prolongados desde las superficies no porosas, como bloques plásticos y vinilo, que de las superficies porosas, como las sábanas.
A diferencia de las cepas del SARM adquiridas en el hospital, el SARM en comunidad podría transmitirse desde objetos plásticos a la piel después de períodos más prolongados.
Un objeto no poroso (hojas de afeitar) no transmitió el SARM más allá de 5 minutos.
Las barras de jabón tampoco transmitieron el SARM a la piel.
A las personas con SARM adquirido en comunidad "se les debería recomendar mantener la limpieza del hogar, en especial las superficies no porosas", destacó Desai.

"Sugerimos limpiar seguido las superficies en los hogares donde viven los pacientes con SARM adquirido en la comunidad para reducir el riesgo de diseminación de la infección al resto de la familia", agregó el autor.

Universal PCR Screening for MRSA May Cut Costs, Reduce Infection

Barbara Boughton

September 13, 2009 (San Francisco, California) — Universal screening using rapid polymerase chain reaction (PCR) analysis for methicillin-resistant Staphylococcus aureas (MRSA) in hospitals appears to be a cost-effective way to reduce the incidence of the disease and cut costs.
That was the finding of a study presented here at the 49th Interscience Conference on Antimicrobial Agents and Chemotherapy. But some scientists say the issue of whether screening with PCR analysis is really useful or cost-effective is far from settled.
In 2005, scientists at NorthShore University Health System in Evanston, Illinois, began screening, with rapid PCR testing, every patient who was admitted to 1 of their 3 hospitals for MRSA. After 1 year and 37,179 patients screened, there was a 70% reduction in MRSA and a cost savings of $1.8 million, according to Lance Peterson, MD, director of microbiology and infectious disease research for NorthShore and clinical professor at the University of Chicago in Illinois.
"The bottom line is that if you want to have a successful MRSA-reduction program and you have modest MRSA colonization rates — as we do in the United States — you have to have a very aggressive, very rapid, and very broad MRSA screening program in a general-hospital population," Dr. Peterson said in a debate on the subject of MRSA screening.
Dr. Peterson's estimates showed that the NorthShore Hospital System spent almost $24,000 more on patients with MRSA than on those without the infection. Although half of that cost is absorbed by insurance and Medicare, the economic bite of MRSA infections makes universal screening worth it, he said. Merely testing patients in the intensive-care unit — as is mandated in several states — doesn't produce enough benefit because not enough patients are tested, according to Dr. Peterson.
In fact, in 2004, before Dr. Peterson's team began their MRSA program, a hospital survey indicated that MRSA prevalence was about 8.5%.
"That was quite high — 3 times higher than other estimates that had been published, and it was the impetus for our universal screening program," he said. After being screened for the infection, those with MRSA were treated with mupirocin and chlorhexidine baths. A more recent survey, in August 2007, indicated that the MRSA prevalence in the hospital had dropped to 5.9%. "The program helped us stop spreading MRSA within the hospital," Dr. Peterson said.
However, other scientists at the conference had doubts about whether universal screening with PCR analysis is the right approach. Stephen Harbarth, MD, from Geneva University Hospital in Switzerland, argued that recent studies have indicated that the reason for the recent decrease in MRSA incidence is actually the widespread adoption of strict hand hygiene. He also noted that studies other than those by Dr. Peterson's group have not found a benefit to PCR screening, especially compared with more conventional methods.
"There is a reduced turnaround time with rapid PCR, but a higher rate of false positives," he said. Published data show that the most important predictors of cost-effectiveness for PCR screening is the baseline prevalence of MRSA, he said. "With a 10% or higher rate of MRSA, rapid testing is cost-effective," he said. But many hospitals have prevalence rates that are quite a bit lower, especially in the European Union, he said.
"Spending half a million to a million [dollars] to do universal PCR screening is a lot of money. But at the same time, it can prevent substantial infections," said John Boyce, MD, from the Hospital of Saint Raphael in New Haven, Connecticut. Dr. Boyce moderated the session at which Drs. Peterson and Harbarth spoke. "The most important thing is that the patient comes out ahead. After all, most of us do what we do to improve patient care," he said.
Dr. Peterson reports receiving research grants from Cepheid, NorthShore, GeneOhm, MicroPhage, Nanosphere, NIAID, Roche, 3M, and the Washington Square Foundation; and being a consultant to Cepheid, GeneOhm, MicroPhage, Nanosphere, Roche, and 3M. Dr. Harbarth reports being a consultant to BioMerieux and Roche. Dr. Boyce reports receiving research support from GOJO Industries and being a consultant to GOJO Industries, Clorox, and Bioquell. 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). Presentation 408. Presented September 12, 2009.