Despite Disinfection, Bugs Thrive on High-Touch Hospital Surfaces

A wide variety of commonplace and unusual pathogenic bacteria were found on hospital surfaces in one Texas hospital, despite compliance with recommended disinfection protocols, a study found.

Researchers identified 60 different kinds of bacteria, including 18 well-known human pathogens, from 400 samples taken from high-touch areas during June and July 2022, reported Piyali Chatterjee, PhD, of the Central Texas Veterans Health Care System in Temple, and colleagues in the American Journal of Infection Control.

Sample sites included simulation manikins, workstations-on-wheels (WOWs), bed rails, break room tables, and computer keyboards at nurses’ stations. Manikins and WOW handles were the two most highly contaminated surfaces, the researchers noted.

“It is a continuing frustration to healthcare professionals that [healthcare-associated infections] persist despite rigorous attention to disinfection practices,” Chatterjee said in a press release.

David Weber MD, MPH, of UNC Medical Center in Chapel Hill, North Carolina and president-elect of the Society for Healthcare Epidemiology of America, told MedPage Today that the findings of the study weren’t surprising. “We don’t live in a sterile world,” he pointed out.

“The strength of this study was the fact that they didn’t look just for the more common organisms but at a much wider variety of organisms,” Weber explained. “Of course, many of the organisms they found would not be considered pathogens, but … it’s worth knowing that these bacteria are on surfaces and to what extent, as we see newer organisms infecting people.”

Susan Kline, MD, MPH, of the University of Minnesota Medical School in Minneapolis, told MedPage Today that “the take-home message from this study is that doctors, nurses, and all ancillary workers need to be aware that these surfaces in the healthcare environment do get contaminated by bacteria. Even if you didn’t touch the patient, you might have touched one of these high-touch surfaces and therefore your hands should no longer be considered clean.”

About half of the isolated hospital surface bacteria (29 out of 60) were also found in clinical samples collected from patients at the facility. Among those bacteria, urine was the most common source, followed by skin and soft tissue, and blood.

Both gram-positive and gram-negative bacterial pathogens were isolated, although gram-positive pathogens were more common (12 vs 6). The most common types of pathogenic gram-positive bacteria included Bacillus cereus group, Enterococcus faecalis, Enterococcus faecium, Micrococcus luteus, Staphylococcus aureus, coagulase-negative Staphylococci, and Streptococcus. Common gram-negative pathogens isolated from the surfaces included Citrobacter freundii, Enterobacter hormaechei, Escherichia coli, Klebsiella aerogenes, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia.

Lesser well-known pathogens included Actinomyces graevenitzii, Enterococcus saccharolyticus, and Acinetobacter spp., some of which can cause serious infections such as meningitis, endocarditis, and central line-associated bloodstream infections in immunocompromised people.

Chatterjee and team sampled and cultured both cleaned and pre-cleaned high-touch hospital surfaces from a single medical-surgical unit during the afternoon after lunch. Five infectious disease physicians and a clinical microbiologist classified the cultured bacteria into well-known and not well-known human pathogens.

Using a laboratory database, surface isolates were matched to clinical isolates and the sources of those bacteria in patients. The researchers did not determine whether the clinical source was a contaminant or associated with an infection.

“Future potential solutions to reduce bioburden on healthcare surfaces may include a combination of different approaches such as enhanced cleaning, use of different chemicals including use of hydrogen peroxide, self-disinfecting surfaces such as copper no-touch devices such as UV-C, or handheld far-UVC devices,” the authors concluded.