By the mid-1940s, penicillin had become more readily available and was found to be highly effective against numerous infectious diseases, including pneumococcal disease. Penicillin quickly became recognized as one of the most effective treatments against S. pneumoniae associated infections. While several pneumococcal vaccines were developed for use between 1909 and the mid-1940s, they were rarely used due to the discovery of penicillin and the preference of its use by doctors for the treatment of the disease.
The discovery of antimicrobials and antibiotics which were found to effectively treat many different infections, including S. pneumoniae, prompted a change in pneumococcal treatment protocols. The culturing and typing of infections were no longer routinely performed by clinicians, with many preferring to administer antibiotics if there were any clinical signs of infection. Some clinicians believed that treating all infections prophylactically with antibiotics would be the safest and most effective way to prevent pneumococcal disease while others chose to prescribe antibiotics at the first sign of any illness.
By the early 1960s, pneumonia researchers, expressing concern over the indiscriminate use of antibiotics, reported that only 10 percent of all persons prescribed antibiotics actually required them. Sulfa resistant strains of S. pneumoniae had already been documented in the 1940s and by the 1960s, penicillin resistant strains had begun to emerge.
Concerns over antibiotic treatment failures and death rates resulting from invasive pneumococcal disease in the 1960s prompted a renewed interest in pneumococcal vaccine development; however, it took researchers until the early 1980s to publish papers suggesting that the overuse of unnecessary antibiotics might be responsible for the increasing number of antibiotic-resistant strains of infection and that this practice should be curtailed. Despite published literature, the scientific community did not sound the alarm over the rise in antibiotic resistant strains of bacteria until the mid-1990s. By 1998, 24 percent of pneumococcal strains were found to be resistant to penicillin and 14 percent of strains were noted to be resistant to multiple antibiotics.
Currently, between 30 and 40 percent of all invasive S. pneumoniae infections are resistant to one or more antibiotics, with resistance found to be dependent on geographical location. Adults over 65 and children under five are most likely to harbor antibiotic resistant strains of S. pneumoniae.
Antibiotic resistance has pushed pneumococcal disease back into the public health spotlight and both the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) consider the need for new treatment approaches to be a priority.
