On the verge of kidney failure and running out of options, 28-year-old Rohit Mehra (name changed) from Mumbai was staring at a grim outcome. A severe urinary tract infection caused by Pseudomonas aeruginosa, one of the hardest-to-treat superbugs, had defied every standard antibiotic. Even drugs like colistin (a powerful but toxic antibiotic used only as a last resort) and polymyxins (a class of kidney-damaging antibiotics given when nothing else works) barely slowed the infection while worsening his kidneys.