The approach to treatment of invasive pneumococcal disease in the 1990s.

ABSTRACT

Streptococcus pneumoniae is the most common cause of pediatric invasive infections and an important cause of morbidity and mortality. In the past, S. pneumoniae responded universally to penicillin until nonsusceptible isolates were first noted in the 1960s. Before 1990, penicillin-nonsusceptible isolates remained a minor component of all reported isolates. Since that time, 20-30% of isolates in many centers in the United States and up to 50% of isolates in some other countries are penicillin-nonsusceptible. Of greater concern has been the development of isolates which are nonsusceptible to more than one antimicrobial agent. This review presents data on pediatric invasive pneumococcal disease in Arkansas and outlines the new treatment recommendations which have been developed in response to these problems. Streptococcus pneumoniae is an important pathogen worldwide and is considered the most common etiology of bacterial sinusitis, otitis media, pneumonia, meningitis and bacteremia. Before 1990, 95-96% of pneumococcal isolates were susceptible to penicillin. The first report of penicillin-nonsusceptible S. pneumoniae was made by Hansman and Bullen in 1967, who identified the strain in the sputum of a patient with hypogammaglobulinemia. Soon thereafter, penicillin-nonsusceptible pneumococci were reported in New Guinea and Australia as well. Over the last several years, the incidence of penicillin-nonsusceptible isolates has greatly increased. Of particular concern is the concomitant increase in the number of organisms that are nonsusceptible to more than one antimicrobial agent. Due to the development of such isolates, clinicians are having to approach patients with invasive disease due to pneumococci more cautiously. In an attempt to clarify confusion with terminology, the Centers for Disease Control and Prevention (CDC) have recommended the same nomenclature be used to classify resistance for all organisms nonsusceptible organisms are those with an MIC (minimal inhibitory concentration) greater than or equal to that defined for the intermediate category of resistance and the term resistant should be reserved for those organisms with an MIC greater than or equal to that defined for the resistant category. Therefore, resistant isolates are a subgroup of the nonsusceptible isolates.