With the discovery of the pneumococcus in 1881, it became apparent that this Gram-positive pathogen was a major cause of serious and often fatal pneumonia (1). It is also a major cause of meningitis and otitis media in children. Pneumococci are the largest cause of community-acquired pneumonia in the developed world. According to the Centers for Disease Control and Prevention, in the United States the combined rates of invasive pneumococcal diseases has shown a decline since the introduction of the conjugate vaccines, with rates among the elderly declining from 59/100,000 in 1998 to 23/100,000 in 2015 and rates among children under 5 years of age falling from 95/100,000 in 1998 to 9/100,000 in 2016 (https://www.cdc.gov/pneumococcal/surveillance.html). The rate of meningitis in children in the United States is about 4 cases per 100,000 children, with a fatality rate of about 15% (2). In the developing world pneumococci are an important cause of childhood deaths due to bacterial respiratory infection following viral disease. The World Health Organization suggests that globally, such infections have been reported to have killed an estimated over 500,000 children in 2008 (http://www.who.int/immunization/monitoring_surveillance/burden/estimates/Pneumo_hib/en/). Recently, about one-third to one-half of pneumococci recovered from humans in the United States have been found to be at least partially resistant to penicillin, and penicillin-resistant strains are frequently also resistant to other common antibiotics (3). The rise of antibiotic resistance among pneumococci has already complicated treatment, especially of meningitis (4), and threatens to greatly increase the morbidity and mortality caused by pneumococci unless new control measures are developed.