Poor hygiene has spread resistant germs into India’s drains, sewers and drinking water, putting millions at risk of drug-defying infections. Antibiotic residues from drug manufacturing, livestock treatment and medical waste have entered water and sanitation systems, exacerbating the problem. India’s $12.4 billion pharmaceutical industry manufactures almost a third of the world’s antibiotics, and people use them so liberally that relatively benign and beneficial bacteria are becoming drug immune in a pool of resistance that thwarts even high-powered antibiotics. The germs — and the gene that confers their heightened powers — are jumping beyond India. More than 40 countries have discovered...