Hospital's Hidden Environmental Hazards: Probing the Microbiome

Abstract

President Barack Obama’s proposed $1.2 billion plan to fight antibiotic-resistant bacteria (ARB) captured headlines (see, e.g., http://io.aibs.org/carpot). Meanwhile, researchers have been tackling dangerous superbugs with little fanfare. Among the newest of these efforts is the Hospital Microbiome Project (HMP), funded by the Sloan Foundation. The project aims to make hospitals safer by understanding the basic ecology of microbial communities that live in healthcare settings. “If we don’t understand how the environment works, we cannot manipulate it to make it better,” says Jack Gilbert, director of the HMP and an environmental microbiologist at Argonne National Laboratory, in Illinois. When the University of Chicago planned to build a new hospital in February 2013, Gilbert and other experts installed reliable and affordable sensors to track environmental data, including humidity, temperature, lighting, and the number of times that people enter and exit a patient’s room. They also collected microbial samples from floors, beds, air vents, sinks, computers, phones, and nurse’s stations on two floors before and after patients were admitted. The microbial data are still being analyzed and will be published early in 2016. However, preliminary results show that before the hospital opened, few human-related microbes were detected. “As soon as it opened, the whole building was flooded with human bacteria,” says Gilbert. Within 24 hours, microbial communities significantly increased in diversity and changed to closely resemble the microbiome of the patient occupying a room. Also, patients taking antibiotics were colonized more by room microbes than were patients not taking antibiotics. The HMP’s first report in PLOS ONE, published in March, verified that standard monitors reliably collect data to predict the growth of microbial communities. “We plan to routinely monitor the environment and rapidly change it to control microbial populations to protect patients,” says Gilbert. Ultimately, the HMP will help patients to heal and recover by designing better hospital environments. The much older Prevention Epicenters Program, started in 1997, coordinates hospital-based studies aimed at thwarting healthcare-acquired infections caused by ARB. Funded by the Centers for Disease Control and Prevention (CDC), the program “aligns public health and academic experts to work together to find innovative strategies to protect patients,” says the CDC’s John Jernigan, director of the program. The CDC estimates that these infections kill 75,000 patients each year. A leading long-term project discovered a pragmatic and inexpensive remedy: bathing susceptible patients with the antiseptic chlorhexidine. In a study of 43 hospitals and 74,000 patients in intensive care units (ICUs), daily chlorhexidine baths reduced by 63 percent bloodstream infections caused by methicillin-resistant Staphylococcus aureus (MRSA). The average cost per patient ran about $40, as published in the New England Journal of Medicine in June 2013. A February 2013 article in the same journal found that daily chlorhexidine bathing of 7727 ICU and bone marrow transplant patients also cut by a third bloodstream infections caused by multidrug-resistant organisms. Chlorhexidine baths “give a big bang for a buck,” says Robert Weinstein, who leads Prevention Epicenter trials at Rush University, in Chicago, one of five national sites. MRSA and other ARB killed by chlorhexidine “are very serious problems in hospitals nationally,” says Weinstein. Chlorhexidine has been available for 50 years. New formulations, such as chlorhexidine-impregnated washcloths, make it easier to use. Researchers monitor for bacterial resistance, and “there’s no evidence of any emerging in our studies,” says Weinstein. The latest analysis found that less than 1 percent of MRSA isolates carry chlorhexidine-resistant genes (see the November 2012 issue of Antimicrobial Agents and Chemotherapy). About half of ICUs now bathe patients with chlorhexidine as a routine practice. “It would be great if we could roll out a chlorhexidine campaign to convince more hospital administrators that it’s the right thing to do,” says Victoria Fraser, head of Preventive Epicenter trials at Washington University, in St. Louis. With the current emphasis on cost containment, administrators “need to know about the cost savings and benefits chlorhexidine baths bring for many different types of patients,” Fraser says. In order to improve care in realworld settings, Prevention Epicenter researchers first conduct proof-of-principle trials to identify procedures that lower infection rates. Then, the process is replicated in diverse hospital settings and geographic locations. “This is tougher to do than animal research,” says Fraser. She adds that funds from Obama’s ARB initiative would “help tremendously to translate patient-oriented research. We need more scientists, doctors, and nurses working in this area,” as well as new antibiotics, rapid detection systems, and therapeutics. Other Prevention Epicenter sites are at Duke University, Harvard Pilgrim Health Care, and the University of Pennsylvania. Ongoing projects include controlling infections among patients who are on ventilators or who are undergoing surgery for orthopedic implants, hysterectomies, and coronary bypass.