Prefectural and municipal public health institutes are located in prefectures and ordinance-designated cities in Japan, and play a vital role in the regional surveillance of infectious diseases and foodborne illnesses. These institutes, in close cooperation with national institutes such as the National Institute of Infectious Diseases and the National Institute of Health Sciences, construct the national surveillance network for infectious diseases and their causative agents. Bacteriological examinations and studies on a variety of infectious diseases and foodborne illnesses are core activities of prefectural and municipal public health institutes, through which novel and important bacteriological findings have been acquired. In this article, we report the latest findings regarding bacteriological examinations/studies and interesting cases at these institutes, especially concerning foodborne illnesses, tuberculosis, and antimicrobial resistances.