ASTM E3180-18
(Test Method)Standard Test Method for Quantification of a Bacillus subtilis Biofilm Comprised of Vegetative Cells and Spores Grown Using the Colony Biofilm Model
Standard Test Method for Quantification of a <emph type="ital">Bacillus subtilis</emph > Biofilm Comprised of Vegetative Cells and Spores Grown Using the Colony Biofilm Model
SIGNIFICANCE AND USE
5.1 Biofilm characteristics such as thickness, matrix architecture, and population are dependent on factors such as shear and nutrient availability and composition. Additionally, sporulation can occur within biofilms, including those formed by Bacillus subtilis.5 The purpose of this test method is to define the parameters to grow and enumerate a B. subtilis biofilm comprised of vegetative cells and spores embedded in extracellular polymeric substance (EPS). This type of biofilm could provide a greater challenge to antimicrobials than vegetative biofilm or spores alone. The biofilm generated using this method is suitable for efficacy testing of antimicrobials.
SCOPE
1.1 This test method specifies the operational parameters required to grow and quantify a Bacillus subtilis biofilm comprised of vegetative cells and endospores (spores) using the colony biofilm method (CBM).2,3 The resulting biofilm is representative of static environments that can develop a sporulating biofilm rather than being representative of one particular environment.
1.2 This test method utilizes a modified CBM to grow the biofilm. The CBM uses a semipermeable membrane on an agar plate as the biofilm growth surface and nutrient source.2,3 In this test method, membranes are inoculated and incubated for a total of 8 days to promote sporulation within the biofilm.
1.3 This test method describes how to sample and analyze the biofilm for vegetative cells and spores. Biofilm population is expressed as total colony forming units (CFU) and spores per membrane.
1.4 Basic microbiology training is required to perform this test method.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:E3180 −18
Standard Test Method for
Quantification of a Bacillus subtilis Biofilm Comprised of
Vegetative Cells and Spores Grown Using the Colony
1
Biofilm Model
This standard is issued under the fixed designation E3180; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This test method specifies the operational parameters
Barriers to Trade (TBT) Committee.
required to grow and quantify a Bacillus subtilis biofilm
comprised of vegetative cells and endospores (spores) using
2. Referenced Documents
2,3
the colony biofilm method (CBM). The resulting biofilm is
4
2.1 ASTM Standards:
representative of static environments that can develop a spo-
E2756Terminology Relating toAntimicrobial andAntiviral
rulatingbiofilmratherthanbeingrepresentativeofoneparticu-
Agents
lar environment.
1.2 This test method utilizes a modified CBM to grow the
3. Terminology
biofilm.TheCBMusesasemipermeablemembraneonanagar
3.1 Definitions—For definitions of terms used in this Test
2,3
plate as the biofilm growth surface and nutrient source. In
Method see Terminology E2756.
this test method, membranes are inoculated and incubated for
3.2 Definitions of Terms Specific to This Standard:
a total of 8 days to promote sporulation within the biofilm.
3.2.1 biofilm, n—microorganisms living in a self-organized
1.3 This test method describes how to sample and analyze
community attached to surfaces, interfaces, or each other,
the biofilm for vegetative cells and spores. Biofilm population
embedded in a matrix of extracellular polymeric substances of
isexpressedastotalcolonyformingunits(CFU)andsporesper
microbial origin, while exhibiting altered phenotypes with
membrane.
respect to growth rate and gene transcription.
1.4 Basic microbiology training is required to perform this
3.2.2 spore, n—a dormant, robust, and non-metabolically
test method.
active structure produced by certain bacteria enabling pro-
1.5 The values stated in SI units are to be regarded as longed survival and greater resistance to deleterious environ-
standard. No other units of measurement are included in this mental factors.
standard.
4. Summary of Test Method
1.6 This standard does not purport to address all of the
4.1 This test method utilizes a modified CBM to grow the
safety concerns, if any, associated with its use. It is the
biofilm. The CBM uses an inoculated semipermeable mem-
responsibility of the user of this standard to establish appro-
brane on an agar plate as the biofilm growth surface and
priate safety, health, and environmental practices and deter-
2
nutrient source. In the published method, the inoculated
mine the applicability of regulatory limitations prior to use.
membranes are transferred to fresh agar plates regularly
1.7 This international standard was developed in accor-
(usually every 8-24 h) to provide new nutrients to the
dance with internationally recognized principles on standard-
membrane-growncellsandareincubatedforatotalofapproxi-
ization established in the Decision on Principles for the
mately48hbeforesamplingorsubjectingthebiofilmtofurther
3
tests. In this test method, membranes are inoculated and
1
This test method is under the jurisdiction of ASTM Committee E35 on
incubated for 24 h before transferring the membrane to a new
Pesticides, Antimicrobials, and Alternative Control Agents and is the direct
media plate.This initial growth step is similar to the published
responsibility of Subcommittee E35.15 on Antimicrobial Agents.
Current edition approved Oct. 1, 2018. Published January 2019. DOI: 10.1520/ CBM and allows the colony biofilm to grow and spread across
E3180–18
2
Anderl, J. N., Franklin, M. J., & Stewart, P. S. (2000). Role of Antibiotic
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Penetration Limitation in Klebsiella pneumoniae Biofilm Resistance to Ampicillin For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Ciprofloxacin. Antimicrobial Agents and Chemotherapy, 44(7) 1818–1824. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Merritt,J.H.,Kadouri,D.E.,andO’Toole,G.A.(2011).Growingandanalyzing Standards volume information, refer to the standard’s Document Summary page on
static biofilms. Current Protocols in Microbiology. 22:B:1B.1:1B.1.1–1B.1.18 the ASTM website.
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