Antimicrobial Susceptibility Testing Is Important To Know Whether The Bacteria Or Fungus Causing The Infection Are Resistant To Certain Drugs

Antimicrobial Susceptibility Testing

 

Antimicrobial Susceptibility Testing (AST) is a key diagnostic test used by medical technologists to determine which antibiotics may be effective against bacterial infections. The test involves growing bacteria, fungi or other microbes in a special medium and then comparing the growth rate to the effect of different antibiotics. This information helps physicians decide which antibiotics to prescribe for their patients.

Antimicrobial susceptibility testing is a laboratory test that helps the healthcare provider select the best antibiotic (drug) to treat a particular infection. Bacterial and fungal resistance can develop due to mutations in the microbe's genetic material that make it less sensitive to antimicrobial drugs. Occasionally, the bacteria can also develop resistance owing to lack of exposure to the drug.

The global antimicrobial susceptibility testing market is estimated to be valued at US$ 3,525.75 million in 2022 and expected to exhibit a CAGR of 6.4% over the forecast period (2022-2030).

Bacteria and fungi can develop resistance to antimicrobial drugs if they are exposed to the drug for prolonged periods of time or if they are exposed to multiple antimicrobial agents simultaneously. Once resistant, the microbes can no longer be killed by the drug and can continue to reproduce and spread to other people in the community or hospital. Infections caused by resistant organisms are more difficult and expensive to treat.

A variety of tests are available to measure the sensitivity of bacteria, fungi and other microbes to antimicrobial agents. The most common method is a semiquantitative technique, which measures the minimal concentration of a drug that prevents growth of the organism in vitro, known as the minimum inhibitory concentration (MIC). This value, also called the zone of inhibition when performed with disk diffusion, is recorded on a table or chart and can be used to categorize the bacteria into groups: S (susceptible), I (intermediate) and R (resistant).

Quantitative methods use an automated instrument to measure the kill (bactericidal) rate of the antibiotic against the microorganism. The data are compared to the kill rates established by the manufacturer of the antibiotic and reported as either susceptible or resistant.

A primary goal of Antimicrobial Susceptibility Testing is to help healthcare providers select the right antibiotic for their patients. This can only be achieved if the clinician knows which antibiotics are likely to work and which ones are not likely to.

The U.S. FDA approved the SPECIFIC REVEAL Rapid Antimicrobial Susceptibility Test System by bioMérieux, in August 2022. This is anticipated to grow the adoption of rapid AST for treating antimicrobial resistance diseases.