在他对医学和公共卫生的众多贡献中，韦尔奇于1892年发现了引起气体坏疽的细菌，以他的名字命名为韦尔氏芽孢杆菌，后来被称为产气荚膜梭状芽胞杆菌或韦氏梭菌。约翰·汉克斯（John Hanks）是该部门的另一位早期成员，以他的汉克斯平衡盐溶液和在麻风杆菌（麻风分枝杆菌）上的开拓性工作而闻名。该部门对分枝杆菌的兴趣现在集中于结核病（TB）的复兴，尤其是多药耐药性结核病（MDR-TB）的出现是主要的公共卫生问题。
Through a departmental core curriculum as well as research area-specific courses, laboratory rotations, qualifying examinations, mentored research, and professional development, all MMI PhD students are prepared to engage in cutting edge research and scholarship that advances knowledge. MMI PhD students hone their scholarship, research and professional skills. Course and laboratory work can address problems in microbial pathogenesis, immunology, disease transmission, and diseases related to malaria, mosquito and arboviral biology.<br>William H. Welch, the founding dean of Johns Hopkins School of Medicine and the School of Hygiene and Public Health, and recognized as the founder of scientific medicine in America (the Dean of American Medicine), also founded MMI, formerly the Department of Bacteriology. Among his numerous contributions to medicine and public health, Welch in 1892 discovered the gas gangrene-causing bacteriumnamed after him as Welch Bacillus, subsequently called Clostridium perfringens or C. welchii. John Hanks, another of the early members of the Department, is famed for his Hanks Balanced Salt Solution and for his pioneering work on the leprosy bacillus (Mycobacterium leprae). The Department's interest in mycobacteria is now focused on the resurgence of tuberculosis (TB) and particularly the emergence of multidrug-resistant tuberculosis (MDR-TB) as a major public health problem.