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Changes Concerning
the Test organisms
Changes to the standard concern mainly the test organism.
In place of the gram-negative test organism
Klebsiella pneumoniae used in previous versions of the
standard, the latest version stipulates the closely related
organism Escherichia coli, which is easier to handle
in the laboratory. Nevertheless, tests can only be performed
by trained personnel in a Category 2 microbiological
safety laboratory because both organisms are
potential pathogens.
The failure to specifically address the gram-positive
bacteria differing in their cell structure in the course of
the revision process remains a drawback. In the stated
objective of the revised standard, mention is made of
its use for a wide range of microorganisms, meaning
that the use of additional or other microorganisms is
permissible.
PFI therefore continues to offer the existing, accredited
test method with the test organisms Staphylococcus
aureus (gram-positive bacterium) and either Klebsiella
pneumoniae or Escherichia coli (gram-negative
bacterium).
Although the ASTM E2149 standard test method for
determining the antibacterial activity of antimicrobial
treated specimens was updated in 2010, only modest
changes were actually made.
01.2011
Magazine of the Test and Research Institute Pirmasens
Enumeration of viable microorganisms:
Each colony (spot) corresponds to a viable
bacterial cell in the original sample
Participants in a seminar on this and other test methods
for determining antimicrobial efficacy towards
bacteria and microfungi, held in late May at the International
Shoe Competence Center in Pirmasens, were
able to gain a deeper insight into this topic.
Further information:
Diplom Biologin Michaela Würtz
Phone: +49 6331- 24 90 550
E-Mail: michaela.wuertz@pfi-germany.de
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