Patients' Bath Basins as Potential Sources of Infection: A Multicenter Sampling Study

Debra Johnson, RN, BSN, OCN, CIC; Lauri Lineweaver, RN, BSN, CCRN; Lenora M. Maze, RN, MSN, CNRN


Am J Crit Care. 2009;18(1):31-38, 41. 

In This Article

Abstract and Introduction


Background: Nosocomial infections are a marked burden on the US health care system and are linked to a high number of patient deaths.
Objective: To identify and quantify bacteria in patients' bath basins and evaluate the basins as a possible reservoir for bacterial colonization and a risk factor for subsequent hospital acquired infection.
Methods: In a prospective study at 3 acute care hospitals, 92 bath basins, including basins from 3 intensive care units, were evaluated. Sterile culture sponges were used to obtain samples from the basins. The culture sponges were sent to an outside laboratory, and qualitative and quantitative microbial tests were conducted and the results reported.
Results: Some form of bacteria grew in 98% of the samples (90 sponges), either by plating or on enrichment (95% confidence interval, 92%-99.7%). The organisms with the highest positive rates of growth on enrichment were enterococci (54%), gram-negative organisms (32%), Staphylococcus aureus (23%),vancomycin-resistant enterococci (13%), methicillin-resistant S aureus (8%), Pseudomonas aeruginosa (5%), Candida albicans(3%), and Escherichia coli (2%). Mean plate counts, in colonyforming units, were 10 187 for gram-negative organisms, 99 for E coli, 30 for P aeruginosa, 86 for S aureus, 207 for enterococci, and 31 for vancomycin-resistant enterococci.
Conclusions: Bath basins are a reservoir for bacteria and maybe a source of transmission of hospital-acquired infections. Increased awareness of bath basins as a possible source of transmission of hospital-acquired infections is needed, particularly for high-risk patients. (American Journal of Critical Care.2009;18:31-40)


Each year, an estimated 1.75 to 3.5 million patients in the United States, 5% to 10%of all patients admitted to US hospitals annually, contract nosocomial infections.[1] Health care–associated infection (HAI) is linked to nearly 90 000 deaths annually,[2] is ranked as the fifth leading cause of death in acute care hospitals, and results in an annual financial burden thought to exceed $6.5 billion.[2] Multiple studies[3,4,5,6] have shown that the cost of care is even higher in hospitalized patients in whom methicillin-resistant Staphylococcus aureus (MRSA) infections develop.

Nobel laureate Robert Koch first correlated high heterotrophic counts of bacteria with tap water hygiene in 1883 in Berlin.[1] Since then, researchers around the globe have substantiated his findings and have, more recently, discovered that in health care facilities such as hospitals, hospices, and residential care centers, contaminated water supplies can spread infection among patients whose health is already compromised.[1,7,8] Infection control measures such as water chlorination, filtration, thermal disinfection, and UV irradiation can decrease microbial counts in hospital water.[1,9,10,11,12]

However, water often is merely a conduit. Pathogens, such as Enterobacter cloacae, can create highly potent biofilms that lodge in hospital pipes, hot water tanks, air conditioning cooling towers, sinks, and even touch less faucets and then contaminate the water upon contact.[1,13,14] Without proper education and hygienic practice, hospital staff can transmit pathogens both into and via water that has become contaminated after contacting a contaminated surface.[15,16]

A review of the evidence suggests a link between waterborne pathogens in the health care setting and the development of biofilm (multiple colonies of microorganisms attached to a surface). The ability of organisms to form a biofilm, combined with transmission of organisms through contact with contaminated items or unwashed hands, can create a reservoir of bacteria that can be transferred to and maintained in a patient's bath basin (defined as a container in which water is placed for use in bathing a patient).

On the basis of ample, documented evidence for microbial colonization of patients' skin, health care facility water supplies, and environmental surfaces such as dry disposable bath basins, we asked the following question: Can patients' bath basins harbor microorganisms that are potential sources of HAI, even after the removal of the possibly contaminated water? A prospective, multicenter study was done to identify and quantify bacteria in patients' bath basins to evaluate bath basins as a possible reservoir for bacterial colonization and as a risk factor for subsequent HAI.


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