Acute bacterial meningitis at Boston City Hospital during 12 selected years, 1935-1972.

Data are presented on the occurrence of and mortality rate from acute bacterial meningitis at Boston City Hospital during 12 years between 1935 and 1972 selected in relation to the introduction of potent antibacterial agents. The most frequent causative organisms were Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, but large proportions were caused by other gram-positive cocci and gram-negative bacilli. The greatest reduction in mortality rate after antibiotics became widely used was in patients with meningococcal and influenzal meningitis who were less than or equal to 19 years old. Less striking reductions occurred in cases of other etiologies in patients less than or equal to 59 years old, but in those greater than or equal to 60 years old, the mortality rate remained high, and the proportion of cases of meningitis in that age group more than doubled. Comparisons with similar data on all bacteremic infections are presented.