Outpatient Infection Control—Managing Microbial Transmission

Outpatient clinics are not traditionally focused on infection control initiatives. Despite 990 million physician office visits and 125.7 million hospital outpatient visits each year in the United States, these clinics are often overlooked when it comes to controlling the transmission of harmful pathogens.

Until recently, acute and long-term care facilities have been viewed as common sources for microbial transmission. Fortunately, focus has slowly been moving to outpatient clinics and the importance of infection prevention measures for patient and health care provider safety. A new study, published in the American Journal of Infection Control, sought to evaluate outpatient clinic microbial transmission and a disinfecting spray’s role in reducing the spread of germs.

“The key takeaway from our outpatient clinic study is that microbes spread quickly throughout the clinic, contaminating the majority of high-touch surfaces after only 2 hours of work activity,” Kelly Reynolds, PhD, MSPH, professor and chair in the Department of Community, Environment, and Policy at the University of Arizona Zuckerman College of Public Health, told Contagion^® in an interview.

The investigators selected a 3000-square-foot outpatient urgent care clinic to perform microbial tracers in order to understand how organisms might spread in this unique environment. The team used bacteriophage MS2, a harmless viral tracer, which has been used as a surrogate for bacteria like E coli and other human viruses in previous transmission studies.

The experiment was broken down into 3 distinct phases, the first of which was a pilot time series evaluating the movement of the tracer virus throughout the clinic over the course of a single day. This was done by contaminating 2 high-touch fomites, including a door handle exiting the patient care area and the pen used for signing in at the front desk. The investigators sampled the hands of staff and patients, and fomites throughout the clinic after 2, 3, 5, and 6 hours.

Phase 2 was a baseline study that collected fomite and hand samples 6 hours after the tracer was placed as typical hygiene practices were continued, including the use of disinfecting wipes.

Phase 3 was an intervention phase in which investigators utilized a new disinfectant, an ethanol-based spray, on specific surfaces that were cleaned every 4 hours after the tracers were applied.

The findings of the study were fascinating. In phase 1, at the 2-, 3-, 5-, and 6-hour marks, the tracer virus was found on all surfaces and hands sampled. In fact, the results did not differ significantly across various time points throughout the day, although there was a decrease of 38% every hour.

The highest levels of contamination were detected on patient door handles, patient hands, staff hands, nurses’ station chair arms, and a computer mouse in the waiting room used for patient surveys. In phase 2 and 3, the investigators found that the patient waiting room and nurses’ station were the most contaminated areas.

“Just as handwashing events occur throughout the workday, surfaces should also be cleaned at additional time to minimize pathogen spread between patients, visitors, health care workers, and the environment,” Dr. Reynolds, who is also the director of the Environment, Exposure Science, and Risk Assessment Center, said in the interview.

Intervention proved effective in decreasing viral tracer concentrations, but the disinfectant spray proved a formidable tool in that concentrations decreased by 94% following use.

Although the disinfectant spray was found to be the most effective tool in decreasing microbial contamination, Dr. Reynolds notes that outpatient settings are known to be tricky when it comes to controlling the spread of bacteria because of increased movement around the site. Dr. Reynolds also notes that outpatient health workers struggle to implement increased hand hygiene and disinfection protocols due to high staff-to-patient ratios.

This study provides considerable insight into the high rate of microbial transmission in outpatient clinics and the desperate need for more infection control focus in these health care settings.

“In addition to promoting increased hand hygiene compliance, we should place more focus on the role of surfaces in healthcare-associated infection transmission to minimize pathogen cross-contamination and exposure risks,” Dr. Reynolds concluded.

This research underscores the potential interventions that exist to reduce microbial spread as well as the work that still needs to be done to reduce disease transmission during outpatient care. As health care shifts to include more outpatient treatments, studies like this will be vital in efforts to strengthen patient and health care workers’ safety.