1、Designation: E1326 13E1326 15Standard Guide forEvaluating NonconventionalNon-culture MicrobiologicalTests Used for Enumerating Bacteria1This standard is issued under the fixed designation E1326; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this guide is to assist users and producers of nonconventionalnon-culture tests
3、 in determining theapplicability of the test for processing different types of samples and evaluating the accuracy of the results. Conventional Culturetest procedures such as the Heterotrophic (Standard) Plate Count, the Most Probable Number (MPN) method and the Spread PlateCount are widely cited an
4、d accepted for the enumeration of microorganisms. However, these methods have their limitations, suchas performance time and degree of accuracy. Moreover any given culture test method typically recovers only a fraction of the totalviable microbes present in a sample. It is these limitations that hav
5、e recently led to the marketing of a variety ofnon-conventionalnon-culture procedures, test kits and instruments.1.2 Aconventional test is one that is widely accepted and published as a standard microbiological method or related procedure.A new, nonconventional test method will Culture test methods
6、estimate microbial population densities based on the ability ofmircoorganisms in a sample to proliferate in or on a specified growth medium, under specified growth conditions. Non-culture testmethods attempt to provide the same or complimentary information through the measurement of a different para
7、meter. This guideis designed to assist investigators in assessing the accuracy and precision of nonconventionalnon-culture methods intended for thedetermination of microbial population densities or activities.1.3 It is recognized that the Heterotrophic Plate Count (HPC) does not recover all microorg
8、anisms present in a product or asystem (1, 2).2 When this problem occurs during the characterization of a microbiological population, alternative standardenumeration procedures may be necessary, as in the case of sulfate-reducing bacteria. At other times, chemical methods thatmeasure the rates of ap
9、pearance of metabolic derivatives or derivatives, the utilization of contaminated product components orgenetic profile of the microbial population might be indicated. In evaluating nonconventional tests, non-culture tests, it is possiblethat the use of these alternative standard procedures maymight
10、be the only means available for establishing correlation. In suchcases, this guide can serve as a reference for those considerations.1.4 SinceBecause there are so many types of tests that could be considered nonconventional, non-culture based, it is impossibleto recommend a specific test protocol wi
11、th statistical analyses for evaluating the tests. Instead, this guide should assist indetermining what types of tests should be considered to verify the utility and identify the limitations of the nonconventional test.1.5 The values stated in SI units are to be regarded as standard. No other units o
12、f measurement are included in this standard.2. Referenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to WaterD3870 Practice for Establishing Performance Characteristics for Colony Counting Methods in Microbiology (Withdrawn 2000)4D4012 Test Method for Adenosine Triphosphate (ATP) Conten
13、t of Microorganisms in WaterD5245 Practice for Cleaning Laboratory Glassware, Plasticware, and Equipment Used in Microbiological AnalysesD5465 Practice for Determining Microbial Colony Counts from Waters Analyzed by Plating MethodsD7687E177 Test Method Practice for Measurement of Cellular Adenosine
14、Triphosphate in Fuel, Fuel/Water Mixtures, andFuel-Associated Water with Sample Concentration by FiltrationUse of the Terms Precision and Bias in ASTM Test Methods1 This guide is under the jurisdiction of ASTM Committee E35 on Pesticides, Antimicrobials, and Alternative Control Agents and is the dir
15、ect responsibility ofSubcommittee E35.15 on Antimicrobial Agents.Current edition approved Oct. 1, 2013May 1, 2015. Published October 2013June 2015. Originally approved in 1990. Last previous edition approved in 20082013 asE1326 08.E1326 13. DOI: 10.1520/E1326-13.10.1520/E1326-15.2 The boldface numbe
16、rs in parentheses refer to the list of references at the end of this guide.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the
17、 ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users con
18、sult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D7847 Guide for Interlaboratory St
19、udies for Microbiological Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE2694E1601 Test Method for Measurement of Adenosine Triphosphate in Water-Miscible Metalworking FluidsPractice forConducting an Interlaboratory Study to Evaluate the
20、 Performance of an Analytical MethodE2756 Terminology Relating to Antimicrobial and Antiviral Agents3. Terminology3.1 For definitions of terms used in this guide refer to Terminologies D1129 and E2756.Defintions:3.1.1 For definitions of terms used in this guide refer to Terminologies D1129, E2756, a
21、nd E177.3.2 Abbreviations:3.2.1 HPCHeterotrophic Plate Count4. Summary of Guide4.1 ASTM standard methods and practices are referenced for use by producers and users in order to determine the potentialutility of the nonconventional test. Users of tests who are unequipped for performing standard micro
22、biological tests are givenrecommendations for seeking out microbiological laboratories that could perform collaborative studies to evaluate and verify theinformation generated with the nonconventional tests. a non-standard, non-culture test.4.2 Recognizing that potential users of non-culture test me
23、thods might not have the resources with which or capabilities forevaluating the utility of non-standard, non-culture test methods, recommendations are provided to assist those users in identifyingthe capabilities that qualify microbiological laboratories to perform collaborative studies to evaluate
24、those methods.5. Significance and Use5.1 This guide should be used by producers and potential producers of nonconventionalnon-culture tests to determine theaccuracy, selectivity, specificity, and reproducibility of the tests, as defined in PracticesPractice E691 and D3870. Results of suchstudies sho
25、uld identify the limitations and indicate the utility or applicability of the nonconventionalnon-culture test, or both, foruse on different types of samples.5.2 NonconventionalNon-culture test users and potential users should employ this guide to evaluate results of thenonconventionalnon-culture tes
26、t as compared to their present methods. Practices D5245 and D5465 should be reviewed in regardsto the conventional microbiological methods employed. If conventionalculture methods have not been used for monitoring thesystems, then guidelines are included for obtaining microbiological expertise.5.3 U
27、tilization of a non-culture test can reduce the time required to determine the microbiological status of the system and detectmicrobe that are not detected by culture testing. Consequently, non-culture tests can contribute to the improvement in the overalloperating efficiency of microbial contaminat
28、ion condition monitoring and diagnostic efforts, and microbicide performanceevaluations.5.4 Utilization of a nonconventional test may reduce the time required to determine the microbiological status of the system andenable an improvement in the overall operating efficiency. In many cases, the findin
29、gs of a significantly high level of bacteriaDetecting microbial contamination levels that exceed predetermined upper control limits indicates the need for an addition of anantimicrobial agent. agent or other corrective maintenance action. By accurately determining this in a shorter time period than
30、byconventionalis possible than by culture methods, treatment with antimicrobial agents may circumvent more serious problems thanif the treatment were postponed until conventionalculture results were available. If the antimicrobial treatment program reliesreliedon an inaccurate nonconventionalnon-cul
31、ture test, then unnecessary loss of product and problems associated with inappropriateselection or improper dosing with antimicrobial agents would exist.5.5 Since many methods based on entirely different chemical and microbiological principles are considered, it is not possibleto establish a unique
32、design and recommend a specific method of statistical analyses for the comparisons to be made. It is onlypossible to present guides that should be followed while performing the experiments. It is also recommended that a statistician beinvolved in the study.5.5 There are various ways for categorizing
33、 microbiological test methods. One valid approach is to differentiate betweenmethods intended to quantify a particular microbe from those intended to quantify overall bioburden.5.5.1 Methods used to quantify a single microbe typically can be evaluated for precision (Practice E691). Even though it is
34、unlikely that reference standards exist, often these methods can also be evaluated for bias relative to other methods used to detectthe same microbe.5.5.2 Methods used to quantify total populations are more problematic in terms of precision and bias testing. Guide D7847addresses many of the factors
35、that confound efforts to determine the precision of microbiological test methods used to quantifymicrobial contamination in fuels and fuel systems. Many of these issues are broadly relevant to the challenge of developingrelevant precision terms for microbiological test methods used to quantify total
36、 bioburdens in industrial systems.E1326 1526. Procedures6.1 Practice E1601 provides guidance on the evaluation of analytical method performance. The guidance provided belowamplifies the processes described in Practice E1601 as they apply to microbiological test methods.6.2 In order Although the hete
37、rotrophic plate count (HPC) has been used historically to determine the utility of thenonconventional test, evaluate and compare the results to those obtained with a previously accepted standard method. TheHeterotrophic Plate Count (Practice newly developed non-culture methods, and can D5465) may be
38、 entirely satisfactory for thispurpose be an appropriate reference method in many cases (3),; however, understand its limitations before it is used as the basisfor evaluating methods that measure other parameters indicative of microbial life (metabolic activity, concentration of cellconstituents, or
39、 whole cell numbers). Several methods used for the Heterotrophic Plate Count are listed in there are cases for Table1. When the Heterotrophic Plate Count is not a suitable refereed method, Adenosine Triphosphate Concentration (Test Methodswhich HPC is not an appropriate refer D4012, E2694, and D7687
40、) or the Most Probable Number (MPN) technique (4) may bemore appropriate. Alternative standard enumeration methods or methods for measuring the rate of the appearance of derivativesor the rate of disappearance of components of the product in which the microbial contamination is being measuredwhere s
41、uchphenomena are known to be correlated to microbial contamination levelsmay also be used as referee methods for assessing theaccuracy and precision of a novel nonconventional method. No single method is universally applicable; consequently, it isimperative to determine the rationale for employing a
42、ny given measurement procedure and to select a standard that will permitthe determination of whether or not the nonconventional method achieves the objectives defined in the scope of the procedure.method6.2.1 The choice of referee method to use for validating a new or proposed non-culture method sho
43、uld be determined based onthe parameter the new method purports to be measuring.6.2.2 Several methods used for the HPC are listed in Table 1.6.2.3 When none of the Table 1 variations of the HPC (Heterotrophic Plate Count) are suitable refereed methods, AdenosineTriphosphate Concentration (Test Metho
44、d D4012) or the Most Probable Number (MPN) technique (7) may be more appropriate.6.2.4 Alternative standard enumeration methods or methods for measuring the rate of the appearance of derivatives or the rateof disappearance of components of the product in which the microbial contamination is being me
45、asuredwhere such phenomenaare known to be correlated to microbial contamination levelsmay also be used as referee methods for assessing the accuracy andprecision of a novel non-culture method.6.2.5 No single method is universally applicable; consequently, it is imperative to determine the rationale
46、for employing anygiven measurement procedure and to select a standard that will permit the determination of whether or not the nonconventionalmethod achieves the objectives defined in the scope of the procedure.6.3 A knowledge of standard microbiological technique is required for this procedure. in
47、order to conduct microbiological testmethod evaluations. If that expertise is not currently available in-house, consult an outside testing laboratory. Many industrialmicrobiology laboratories are certified for the analysis of drinking water by the EPA or the state government (a listing of theselabor
48、atories can be obtained from the regional EPA office or the state government). There are also other microbiology laboratoriesthat specialize in processing samples from different industries; these are often listed as “LaboratoriesTesting” in the telephonebook. It is important that this document be re
49、ferenced when undertaking an evaluation with an outside laboratory.6.3.1 Many industrial microbiology laboratories are certified for the analysis of drinking water by the EPA or the stategovernment, or both (a listing of these laboratories can be obtained from the regional EPA office or the state government).6.3.2 These and other independent microbiology laboratories often specialize in processing samples from different industries6.3.3 Suitable microbiology laboratories are typically often listed as “LaboratoriesTesting” in the telephone book or indirectories such as the
