IIT Bombay study shows how TB bacteria shield themselves from antibiotics

The bacteria Mycobacterium tuberculosis which causes the worldrsquos most infectious disease Tuberculosis TB can survive antibiotic treatment and live longer by changing their outer fat coating according to a new study led by researchers from the Indian Institute of Technology IIT Bombay on WednesdayEven with effective antibiotics and widespread vaccination campaigns TB continues to take livesGlobally 107 million people developed TB and 123 million died from the disease in 2024 while India carries one of the highest burdens over 271 million cases in 2024In the study published in the Chemical Science journal the researchers showed that the key to the bacterias drug tolerance lies in their membranes complex barriers made mostly of fats or lipids that protect the cellThe team grew the bacteria under two conditions an active phase when the bacteria were dividing rapidly as they do in an active infection and a late stage mimicking dormancy as seen in latent infectionsWhen they exposed the bacteria to four common TB drugs rifabutin moxifloxacin amikacin and clarithromycin the team found that the concentration of drugs needed to stop 50 per cent of bacterial growth was two to 10 times higher in dormant bacteria than in active onesIn other words ldquothe same drug that worked well in the early stage of the disease would now be needed at a much higher concentration to kill the dormantpersistent TB cells This change was not caused by genetic mutations which usually explain antibiotic resistancerdquo said Prof Shobhna Kapoor from the Department of Chemistry IITBLack of mutations associated with antibiotic resistance in the bacteria confirmed that the reduced drug sensitivity could be linked to the bacteriarsquos dormant state and most likely their membrane coats rather than genetic changesFurther the team identified more than 270 distinct lipid molecules in the bacterial membranes which showed clear differences between active and dormant cellsWhile the active bacteria had loose fluid membranes the dormant ones had rigid tightly ordered structures indicating its defence mechanismldquoPeople have studied TB from the protein point of view for decadesrdquo said KapoorldquoBut lipids were long seen as passive components We now know they actively help the bacteria survive and resist drugsrdquo she addedNext the team found that the antibiotic rifabutin could easily enter active cells but barely crossed the outer membrane of dormant onesldquoThe rigid outer layer becomes the main barrier It is the bacteriumrsquos first and strongest line of defencerdquo explained KapoorIf the outer membrane blocks antibiotics weakening it could make the drugs work betterldquoEven old drugs can work better if combined with a molecule that loosens the outer membranerdquo said Kapoor noting that the approach makes bacteria sensitive to the drugs again without giving them a chance to develop permanent resistanceThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever