Rethinking Sterile: The Hospital Microbiome
Rethinking Sterile: The Hospital Microbiome
In 2010 (the latest year for which data are available) 35.1 million Americans spent at least one night in a hospital. The Centers for Disease Control and Prevention estimates that 5% of patients admitted to hospitals will acquire an infection during their stay, potentially leading to 99,000 deaths annually and costing $10 billion per year.
Hospital-acquired infections aren't a new phenomenon. As long as sick people have sought care in hospitals, there has been the potential for the spread of infectious disease. With the advent of penicillin and other antibiotics, concerns about disease transmission diminished because physicians believed they had a magic bullet to fight whatever infections a person might acquire. The rise of antibiotic-resistant bacteria has changed that thinking.
Today, antibiotic-resistant infections show no signs of stopping, nor do hospital-acquired diseases. Historically, these infections have been blamed on the presence of harmful bacteria, and increasingly stringent infection-control procedures and standards for sterility have been seen as the solution. A new hypothesis says that hospital-acquired infections are being driven not by the existence of harmful microbes but by the absence of helpful species.
Underneath the bright lights and on the stainless steel gurneys lives a large community of microorganisms, most of which are harmless and some potentially beneficial. Hospital microbiomes, some researchers think, form a key part of a hospital's "immune system" and in some cases may help protect patients against infectious diseases.
"For the past 150 years, we've been literally trying to just kill bacteria. There is now a multitude of evidence to suggest that this kill-all approach isn't working," Gilbert says. "We're now trying to understand that maybe, just maybe, if we could cultivate nonpathogenic bacteria on hospital surfaces, then we could see if that would lead to a healthier hospital environment."
Human microbiome research has shown that the use of antibiotics can disrupt the normal array of microbes that live in and on our bodies. The constant attempts at sterilization in hospitals might function on a similar level—the use of broad-spectrum antibiotics, bleach, and hand sanitizer might take out some of the harmful pathogens, but it also cuts a swath through the hordes of nonpathogenic microorganisms.
The elimination of these commensal microbes reduces competition, potentially making hospitals more friendly toward pathogenic species, Eisen notes. "Some sterilization efforts may not be helpful in the long run because you're going to be clearing out ecosystems which are then vulnerable to being recolonized by pathogens and not just regular, boring bacteria," he says.
"The vast majority of these microbes are barely surviving," says microbial ecologist James Meadow, a postdoc at the Biology and the Built Environment Center at the University of Oregon. "The built environment appears to be more of a waiting room for these potentially harmful bacteria until better conditions are present. Very few are actually enjoying themselves." The elimination of other microbes might take the destructive pathogens out of the waiting room and into action.
Hospital-Acquired Infections
In 2010 (the latest year for which data are available) 35.1 million Americans spent at least one night in a hospital. The Centers for Disease Control and Prevention estimates that 5% of patients admitted to hospitals will acquire an infection during their stay, potentially leading to 99,000 deaths annually and costing $10 billion per year.
Hospital-acquired infections aren't a new phenomenon. As long as sick people have sought care in hospitals, there has been the potential for the spread of infectious disease. With the advent of penicillin and other antibiotics, concerns about disease transmission diminished because physicians believed they had a magic bullet to fight whatever infections a person might acquire. The rise of antibiotic-resistant bacteria has changed that thinking.
Today, antibiotic-resistant infections show no signs of stopping, nor do hospital-acquired diseases. Historically, these infections have been blamed on the presence of harmful bacteria, and increasingly stringent infection-control procedures and standards for sterility have been seen as the solution. A new hypothesis says that hospital-acquired infections are being driven not by the existence of harmful microbes but by the absence of helpful species.
Underneath the bright lights and on the stainless steel gurneys lives a large community of microorganisms, most of which are harmless and some potentially beneficial. Hospital microbiomes, some researchers think, form a key part of a hospital's "immune system" and in some cases may help protect patients against infectious diseases.
"For the past 150 years, we've been literally trying to just kill bacteria. There is now a multitude of evidence to suggest that this kill-all approach isn't working," Gilbert says. "We're now trying to understand that maybe, just maybe, if we could cultivate nonpathogenic bacteria on hospital surfaces, then we could see if that would lead to a healthier hospital environment."
Human microbiome research has shown that the use of antibiotics can disrupt the normal array of microbes that live in and on our bodies. The constant attempts at sterilization in hospitals might function on a similar level—the use of broad-spectrum antibiotics, bleach, and hand sanitizer might take out some of the harmful pathogens, but it also cuts a swath through the hordes of nonpathogenic microorganisms.
The elimination of these commensal microbes reduces competition, potentially making hospitals more friendly toward pathogenic species, Eisen notes. "Some sterilization efforts may not be helpful in the long run because you're going to be clearing out ecosystems which are then vulnerable to being recolonized by pathogens and not just regular, boring bacteria," he says.
"The vast majority of these microbes are barely surviving," says microbial ecologist James Meadow, a postdoc at the Biology and the Built Environment Center at the University of Oregon. "The built environment appears to be more of a waiting room for these potentially harmful bacteria until better conditions are present. Very few are actually enjoying themselves." The elimination of other microbes might take the destructive pathogens out of the waiting room and into action.
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