The purpose of the study was to validate the Epsilometer test (E-test) method for antimicrobial susceptibility testing of selected periodontopathic microorganisms. ETEST is a well-established method for antimicrobial susceptibility testing in microbiology laboratories around the world. ETEST consists of a predefined. We describe the applicability of the E test (AB Biodisk Solna, Sweden), a new method for determining minimum inhibitory concentrations of antimicrobial agents.

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The major disadvantages of the agar dilution are the time-consuming and the epsllometer tasks of preparing the plates and inocula, especially as the number of different antimicrobial agents to be tested against each isolate increases.

Etest products for more than antimicrobial agents, including antibiotics, antifungal agents and antimycobacterial agents are available. Your email address will not be published. Comparison of agar diffusion methodologies for antimicrobial susceptibility testing of Pseudomonas aeruginosa isolates from cystic fibrosis patients.

Therefore, for reliable and reproducible results, the stability of the gradient must be maintained for many hours. Like the agar disk diffusion method, the E test is easy to execute. Clinical Product Line Industrial Microbiology.

Other methods for susceptibility testing include: Meningitis due to mixed infection with penicillin-resistant and penicillin-susceptible strains of Streptococcus pneumoniae. Please help improve it or discuss these issues on the talk page. A few key references are as follows:.

It can also be used in a macromethod format to optimize resistance detection. However, the results of such measurements are not an absolute value because they are influenced sometimes markedly, by the test conditions used. Overview Specs Downloads Publications Overview Quantitative MIC data is a prerequisite for the management of critical infections, including sepsis, especially among critical care patients.

Views Read Edit View history. E test is a quantitative technique that is based on combination of concept of both dilution and diffusion principle for susceptibility testing. An incubation epsilometsr of only 3 to 5 hours may not be adequate for expression of all bacterial resistance mechanisms; e,g.

E-test: a new technique for antimicrobial susceptibility testing for periodontal microorganisms.

This article has multiple issues. Etest and related instruments offer one of the most efficient methods for generating on-scale MIC values across 15 doubling dilutions for susceptibility testing of a wide range of drug-bug combinations, including fastidious organisms.


The convenience afforded by the availability of dilution susceptibility testing in broth microdilution trays has led the widespread use of microdilution methods in the United States and other developed countries. This is a test yields a qualitative result, such as classification of the organisms as being either susceptible, intermediate or resistant. National Committee for Clinical Laboratory Standards.

After incubation, bacterial growth becomes visible, symmetrical inhibition ellipse along the strip is seen.

Differences between Prokaryotic and Eukaryotic cells. Leave a Reply Cancel reply Your email address will not be published. E-test is a laboratory test used to determine minimum inhibitory concentration MIC and whether or not a specific strain of bacterium or fungus is susceptible to the action of a specific antibiotic.

Quantitative MIC data is a prerequisite for the management of critical infections, including sepsis, especially among critical care patients.

E-test: a new technique for antimicrobial susceptibility testing for periodontal microorganisms.

In the study of Jorgensen et al, Epsilometeg penumoniae and 50 Hemophilus influenzae that demonstrated various resistance mechanisms and levels of anti-microbial suscetibility were examined by E tests performed on agar media currently recommended by the NCCLS HTM and Muller-Hinton sheep blood agars, respectively.

Performance standards for antimicrobial disk diffusion test standard, M2-T4, 2nd ed.

More than antibiotics are now available in the product range for testing of aerobic bacteria and fastidious organisms such as Pneumococci, Haemophilus, H. The E test approach may be well suited for the testing of certain fastidious bacteria or bacteria that is difficult to test. This page was last edited on 21 Augustat National Committee for Clinical Laboratory Standards: One or more E test strips for the antimicrobial agents to be tested are then placed on the inoculatated agar surface.

The purpose of the study was to validate the Epsilometer test E-test method for antimicrobial susceptibility testing of selected periodontopathic microorganisms using the agar dilution method as a standard.

To order please visit: These factors make the standardization of susceptibility testing crucial. The predefined Etest gradient remains stable for at least 18 to 24 hours; that is, a period that covers the critical times of many species of fastidious and non-fastidious organisms.


The E test overcomes some disadvantages of disk diffusion and broth dilution procedures. We did not have any problems for interpreting the results. The E-test has been developed to provide a direct quantification of antimicrobial susceptibility of microorganisms. E test strip is placed on to an inoculated agar plate; there is an immediate release of antibiotics from the plastic carrier surface into the agar surface.

It is technically simple and requires careful attention to de-tails, leading to reproducible results. The range of drug dilution offered by these methods is usually very narrow. E test strip is a non-porous plastic strip immobilized with predefined continuous and stable gradient of 15 antibiotic concentrations on one side and printed with an MIC scale on the other side of nylon strips.

When the Etest strip is placed on an agar surface, the antibiotic gradient on the strip is simply transferred to the agar matrix creating an imprint of the gradient on the strip in the agar.

These media may require supplemental nutrients to obtain enhanced growth of nutritionally fastidious organisms such as pneumococci, streptococci, Abiotrophia, Haemophilus, gonococci, meningococci and Campylobacter. It may require cleanup to comply with Wikipedia’s content policies, particularly neutral point of view. The deficiencies of the disk diffusion test are its non-quantitative interpretation and its inapplicability to many fastidious organisms and anaerobes.

However, to maximise reproducibility, the medium chosen should fulfil the basic requirements for a susceptibility test medium. The E test was also compared with agar dilution using other fastidious and resistant bacterial Current instruments utilize either the principle of turbidity detection of bacterial growth in a liquid medium or detection of hydrolysis of a fluorogenic substrate incorporated in a special liquid medium The E test inhibition ellipses were clearly demarcated, and the points of intersection of the zone edge with the strips were generally easy to interpret figure 2.

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