American pediatrician and microbiologist Hattie Alexander was born #OTD in 1901.
She is particularly renowned for her groundbreaking work on the treatment and prevention of Haemophilus influenzae type B (Hib) infections, which cause meningitis, pneumonia, and other serious illnesses, especially in children. In the course of her research on antibiotics, she noted and reported the appearance of antibiotic-resistant strains of Hib which was caused by random genetic mutations in DNA.