New Delhi: Infections that once responded to commonly prescribed antibiotics may now require stronger medicines or alternative treatments. One of the major reasons behind this change is antimicrobial resistance (AMR), a process in which bacteria, fungi and other microorganisms develop genetic changes that reduce the effectiveness of drugs designed to treat them.
These changes can involve antimicrobial resistance genes, commonly known as AMR genes. They help microorganisms survive exposure to medicines through different biological mechanisms. Understanding how these genes work is important for identifying resistant infections and helping doctors choose appropriate treatments.
How Do AMR Genes Make Infections Resistant?
The type of resistance a microorganism develops depends partly on the genes it carries. Different AMR genes enable microbes to overcome the effects of antimicrobial drugs in different ways.
Some genes allow microorganisms to produce enzymes that break down antibiotics before the medicines can work. Others alter the specific structures that drugs normally target, making it harder for the treatment to act effectively. Certain resistance mechanisms also enable microorganisms to pump medicines out of their cells before the drugs can cause sufficient damage.
Resistance can spread beyond the organism in which it first develops. Some AMR genes can move between different bacteria, allowing resistance mechanisms to spread even among organisms that are not closely related.
Genomic surveillance in India has identified several resistance markers in microorganisms associated with serious infections. These include Escherichia coli (E. coli), Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa.
Each organism can have a different resistance profile. As a result, identifying the pathogen responsible for an infection may not always provide enough information to determine which antibiotics are likely to work.
Why AMR Gene Testing Is Important
Timely diagnosis can be crucial when treating a serious infection. Conventional culture-based testing remains an important method for identifying bacteria and assessing their susceptibility to different antibiotics.
Molecular testing can provide additional information by screening for genetic markers associated with specific pathogens and resistance mechanisms. These tests may help clinicians understand whether particular forms of antimicrobial resistance could be affecting a patient’s infection.
For suspected bloodstream infections, specialised real-time polymerase chain reaction (RT-PCR) panels can detect multiple bacterial and fungal pathogens, along with clinically significant AMR genes, directly from a blood sample.
Identifying these markers can give the medical team an earlier indication that a resistance mechanism may be present. This information can be particularly useful when treatment decisions need to be made quickly.
However, detecting a resistance gene does not automatically establish the complete drug susceptibility profile of an infection. Test findings must be interpreted alongside the patient’s condition and other laboratory results.
Who May Benefit From AMR Testing?
Molecular and genomic testing can be particularly relevant when infections are severe, complicated or progressing rapidly. Doctors may consider such testing for patients who have risk factors associated with resistant infections.
These factors can include recent antibiotic use, previous hospital exposure or an infection that is not improving as expected despite treatment.
Early information about potential resistance mechanisms may help clinicians reassess treatment when the initial response is inadequate. The usefulness of testing depends on the clinical situation, the suspected infection and the tests available.
AMR gene testing is not intended to replace clinical judgement or conventional antibiotic susceptibility testing in every case. Instead, it can provide an additional source of information to support medical decisions, particularly when delays in identifying resistance could affect treatment outcomes.
Disclaimer: This article is intended for general educational purposes only and does not replace professional medical advice, diagnosis or treatment. The selection of diagnostic tests and antimicrobial medicines should be determined by qualified healthcare professionals based on the patient’s condition and laboratory findings. Patients should not start, stop or change prescribed antibiotics without consulting their doctor.
