and Inhibition zone diameter distributions of microorganisms without
and with resistance mechanisms
website gives MIC distributions for individual organisms and antimicrobial
agents in tables and histograms. The distributions are based on collated
data from an increasing total of more than 20000 MIC distributions
from worldwide sources. Unless otherwise specifically stated, the data are
representative of results obtained with a variety of MIC methods. Different
methods do not give exactly the same results but the results rarely vary by
more than one doubling dilution step. In this way the aggregated MIC
distributions encompass the variation between different investigators and
between different methods.
zone diameter distributions
website gives inhibition zone diameter distributions for individual
organisms and antimicrobial agents in tables and histograms. The distributions
are based on collated data from an increasing number of
sources worldwide. The data are representative of results obtained
with the EUCAST disk diffusion method (launched in 2009 - see www.eucast.org).
are shown to the right of the MIC distribution in the tables and the bottom
right-hand corner of each histogram in the form S<X/R>Y mg/L.
are shown to the right of the distribution in the tables and the bottom
right-hand corner of each histogram in the form S>X/R<Ymm.
epidemiological cut-off value (ECOFF)
separates microorganisms without (wild type) and with acquired resistance
mechanisms (non-wild type) to the agent in question. The epidemiological
cut-off value is shown in the tables and the bottom left-hand corner of each
histogram in the form WT<X mg/L or WT>Y mm.
studies use different MIC ranges, which may particularly affect the upper part
of the MIC ranges. Distributions with severely truncated MIC distributions are
not included. Also the collated distributions include studies from a wide
variety of sources and time periods and some include high proportions of
resistant organisms, so the distributions must not be used to represent rates
of resistance to any agent and cannot be used to compare resistance rates among
cite data from the EUCAST program
suggest the format "European Committee on Antimicrobial Susceptibility
Testing. Data from the EUCAST MIC distribution website, last accessed Day Month
contribute MIC- or zone diameter distribution data
send data to firstname.lastname@example.org. It is much
appreciated if you download and use one of the Excel files for bacteria or
fungi, following the instructions in the spreadsheet.
Frequently asked questions
is the purpose of the MIC distributions?
material for committees involved in decisions on clinical breakpoints
material for epidemiological cut-off values for antimicrobial resistance
MIC ranges of wild type organisms for a wide spectrum of species and
reference for calibration of antimicrobial susceptibility testing methods.
What is the source of the data?
The distributions include data from national and
international studies such as the BSAC, NORM, SENTRY, MYSTIC and GENARS
resistance surveillance programmes, as well as MIC distributions from published
articles, the pharmaceutical industry, veterinary programmes and individual laboratories.
MIC determination and disk diffusion methods are represented?
distributions represent MIC values determined with methods described by ISO,
EUCAST, BSAC (UK), CA-SFM (France), CRG (The Netherlands), DIN (Germany), NWGA
(Norway), SRGA (Sweden) and CLSI (USA). Commercial MIC-determination methods
standardized to any of the recognised methods are also included.
zone diameter distributions are based on inhibition zones generated by the
EUCAST disk diffusion method only.
data obtained with a specific method been excluded?
MIC data no specific method has been excluded. Contributions are screened by
the EUCAST Steering Committee and less than 10% have been excluded from the
aggregated distributions. However, all data are held in the database and are
accessible to the Steering Committee. The most common reason for exclusion has
been that the MIC ranges were truncated (not full-range) so that a significant
proportion of MICs were outside the tested range (especially when at the low-end
of the distribution).
inhibition zone diameter data, only data generated with quality controlled
EUCAST disk diffusion methodology has been included. Thus, the upper part,
representing organisms without acquired resistance, can be used
to calibrate methodology. The corresponding part of distributions
from different laboratories should coincide.
is the origin of the organisms included in the data?
data are from tests on bacteria and fungi collected from man and animals, of
any geographic origin and over a wide timeframe.
does "Data not released for public use" imply?
of the antimicrobials in the pull-down list are followed by the text "data
not released for public use". The process of harmonizing clinical
breakpoints across Europe and of defining the epidemiological cut-off values is
co-ordinated with the collection of relevant MIC data. As decisions on
breakpoints are made for each group of antibiotics the data are released for
can I get more information?
EUCAST – email addresses and information can be obtained through the EUCAST
website at http://www.eucast.org.