Cleanlink News March 8 2010
Study: Bulk Soap Harbors Bacteria
Approximately
23% of the soap from open refillable (bulk soap) dispensers in public restrooms
is highly contaminated with bacteria. A recent study confirms that bulk soap
dispensers in schools are similarly tainted.
The
findings of a study of bulk soap dispensers in a school were recently presented
at a meeting of the National Association of School Nurses (NASN) held in
Boston. Among other things, the
study found that washing with soap from bulk
dispensers left ten times as many bacteria on students’ hands as was found on
hands washed with soap from sealed refills. The research also suggests that contaminated bulk soap may
play a role in the transmission of bacteria in schools, particularly among
children.
Problem
Bulk dispensers
are refilled by pouring soap from a large container into an open
reservoir. Typically the nozzle
that dispenses the soap is not replaced. In contrast, sealed dispensing systems
utilize sealed bags or cartridges that contain soap, along with a new nozzle.
Soap in bulk
dispensers is prone to contamination because the soap is constantly exposed to
bacteria from the environment, such as from the hands and body of the person
refilling the soap, the spray of toilet water after flushing, and even from
dust in the air.
In
previous studies, soap from more than 500 dispensers across the United States
was tested to evaluate the prevalence of contaminated soap in public restrooms.
“We were surprised to learn that the soap from one in four bulk dispensers is contaminated
with an average of more than three million bacteria, many of which are known to
be opportunistic pathogens,” said Carrie Zapka, microbiology scientist, GOJO
Industries. “Exposure to such high levels of these organisms can be a significant health
risk to individuals with compromised immune systems – estimated to be at least
20% of the population. In contrast, soap from sealed dispensing
systems was free from contamination.”
In
addition to Zapka, others who were involved in helping to conduct the study
include Dr. Charles P. Gerba and Sheri L. Maxwell, both from the University of
Arizona; and David R. Macinga, microbiology principal scientist, Michael J.
Dolan, senior advisor/science and technology vice president, and James W.
Arbogast, skin care science and technology director, from GOJO Industries.
Since
contaminated bulk soap has caused outbreaks in hospitals, the U.S. Centers for
Disease Control (CDC) recommends against the use of “topping off” dispensers in
healthcare settings. However, no such guidelines exist to protect students in
schools or patrons of public restrooms in the community.
Test Methodology
To determine
whether or not bulk soap dispensers in a school setting contain bacteria, 10
staff members and 10 students in an elementary school participated in a hand
washing study. The objective of this study was to evaluate bacterial hand
contamination and hand transmission among children and adults in an elementary
school with a contaminated bulk soap problem.
In a particular
elementary school in Ohio, it was determined that the antibacterial soap in all
of the school’s dispensers was highly contaminated with 19 different species of
bacteria, including Pseudomonas,
Providencia, Citrobacter, Stenotrophomonas, Aeromonas, Enterobacter,
Pasteurella, and Serratia.
Each of the 20
students and staff participated in up to four hand washes each, using one of 14
contaminated bulk soaps. Participants were instructed to wash and dry their hands as they
normally would after using the restroom. All hands were tested both before and
after handwashing using two different methods: the number of bacteria on one hand of each participant was measured;
and the bacterial transfer to a surface was measured with the opposite hand
using a technique known as “the hand stamp procedure”.
In a follow-up
study conducted four months after the contaminated bulk soap dispensers were
replaced with sealed soap dispensing systems, 11 staff participated in up to
two hand washes each.
The results of
the school study demonstrated that washing with contaminated bulk soap
increased the number of bacteria on hands, and also increased the number of
bacteria transferred
from hands to surfaces. Among the findings:
Washing with contaminated bulk soap
significantly increased the number of pathogenic bacteria per hand from 179 to
2047 on average for all students and staff. Students’ hands retained significantly more bacteria than
staff members’ hands.
Washing with contaminated bulk soap
significantly increased the number of bacteria transferred to a surface from
one before washing to 27 after washing on average for all students and staff.
Also, students transferred significantly more bacteria to the surface they
touched after washing with contaminated bulk soap than the staff did,
specifically 38 vs. 9 bacteria.
Washing with sealed soap significantly
reduced the number of bacteria from 821 to 135.
Hands washed with contaminated bulk soap
transferred a significantly higher number of opportunistic pathogens to touched
surfaces compared to hands washed with soap from a sealed refill.
The
study also concluded that contaminated bulk soap may play a role in the
transmission of bacteria in schools, particularly among children. It was noted that schools using bulk
soap dispensers could reduce the spread of bacteria simply by changing to
dispensers which utilize only sealed soap refills.
