Healthcare Hygiene magazine December 2019 | Page 37

environmental hygiene
By J. Darrel Hicks, BA, MREH, CHESP
Hand Grenades and Horseshoes
F
ew people remember that it was baseball
the germs to hide, and change the chemical
great Frank Robinson who first said,
nature of the disinfectant.
“Close don’t count in baseball. Close only
The number of bacterial survivors is
counts in horseshoes and hand grenades.”
very important because they can quickly
The quote appeared in Time magazine (July
increase their populations exponentially/
31, 1973). But what does that phrase mean?
logarithmically. For example, Staphylococcus
It means that the world is usually binary —
aureus (under ideal conditions) doubles in 24
you win/you lose, you hit/you miss. If you
to 30 minutes.
lose a baseball game 12–11, you only lost by
This means 1,000 or 10ˆ3 or Log 3,
one run, but you lost. Think of “Close but no
bacterial survivors would increase to 2,000
cigar.” This phrase gives an example of being
after 30 minutes, after 60 minutes they
If the healthcare
close and uses alliteration at the same time.
would increase to 4,000, after two hours
surfaces are to be safe, to 16,000 and then increase to more than 1
In order for a chemical to claim disinfection
it must attain a 6-log reduction of specific
clean and disinfected, million after five hours or more if the growing
organisms, in a prescribed amount of time.
is right.
we must have better environment
While sterilization means at least a 6+
When it comes to disinfection of envi-
products, processes
log reduction while leaving no growth or
ronmental surfaces, close doesn’t count.
viable survivors.
only do “Survivors” replicate quickly
and staff education Not
It is important to understand what log
and efficiently, but they can also become
about their role in
reduction is and why it is important to the
resistant to disinfectants.
process of surface disinfection, surface
To improve outcomes of room disinfec-
infection prevention.
sterilization and surface decontamination.
tion, disinfectants should only be applied
Scientists and other professionals who are
to pre-cleaned surfaces according to the
responsible, or even legally responsible, for preventing illness Environmental Protection Agency (EPA) and the Centers for
and contamination are concerned with log reduction or Disease Control and Prevention (CDC). These agencies require
elimination of pathogenic bioburden.
that any hospital cleaning process that claims efficacy against
The term “log” is short for logarithm, a mathematical
C. diff spores must achieve no growth, which means no
term for a power to which a number can be raised (e.g., survivors that can multiply and create new bacterial colonies.
using 10 as the given number, a log-2 increase can be shown
There is nothing about the EPA’s use of the AOAC Use-Di-
as 10ˆ2 or 10 x 10=100). Alternatively, a log reduction is lution Test. The AOAC Use-Dilution Test is far removed from
taking the power in the opposite direction. For example, a
“real-life” use of disinfectants. The most glaring separation
log reduction of 1.0 log is equivalent to a 10-fold reduction.
from “real life” product usage is that contaminated surfaces
Or, stated another way, moving down one decimal place, a are submerged in excess disinfectant for the entire contact
90 percent reduction.
time (up to 10 minutes). Add to that the fact that sterile
Healthcare surfaces can be contaminated with pathogenic
water is used for application of the disinfectant.
organisms (bioburden), and only achieving a log reduction
The role of professional cleaning staff in hospitals is
below 6-log means dangerous viruses, bacteria, fungi and
dependent on the best disinfectant products that have been
Clostridium difficile (C. diff) spores can or will survive and vetted in real world conditions of damaged furniture and
repopulate surfaces within the treated area. The literature has finishes, water hardness, and education about the prevention
shown that bioburden can be spread around to contaminate
and transmission of disease. That’s the challenge confronting
patients and/or grow new bacterial and fungal colonies on
the environmental services department.
new surfaces.
In closing, if the healthcare surfaces are to be safe, clean
A disinfectant kills microbes; however, depending on the
and disinfected, we must have better products, processes
pathogen, preventing the microbes from getting a foothold and staff education about their role in infection prevention.
by removing food and moisture (two essentials for sustaining Being “close” just isn’t good enough.
living organisms) may, in the long-term, be as effective as a
chemical disinfectant.
J. Darrel Hicks, BA, MREH, CHESP, is the owner/principal
In fact, most chemical disinfectants can’t do their job
of Darrel Hicks, LLC and the author of the book Infection
when greater than 5 percent organic soil is in the way. Soil Prevention for Dummies. He is also a board member of the
can absorb the active ingredient, provide more places for Healthcare Surfaces Institute.
www.healthcarehygienemagazine.com • december 2019
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