The Emergence of Penicillin-Resistant Streptococcus pneumoniae in Connecticut and an Evaluation of Hospital Laboratory Susceptibility Testing Practices

INTRODUCTION Streptococcus pneumoniae, a leading cause of morbidity and mortality in the United States, is the most common cause of community-acquired pneumonia, bacterial meningitis, acute otitis media, and bacteremia. 1 Pneumococcal infections are among the most common reasons for acute-care office visits and hospitalization, and cause an estimated 40,000 deaths annually in the United States. 2,3 Although S. pneumoniae was once considered to be uniformly susceptible to penicillin, the prevalence of pneumococcal isolates resistant to penicillin and other antimicrobial agents has increased substantially in the United States since the early 1990s. The emergence of drug-resistant S. pneumoniae complicates the treatment of pneumococcal infections, which are often treated empirically, without knowing whether the infecting strain is susceptible or resistant to the antibiotic selected. Because geographical variations in the prevalence drug-resistant S. pneumoniae have been demonstrated, 4,6,9 information about its regional prevalence is essential for the selection of appropriate antimicrobial therapy. Inappropriate antimicrobial use, such as treating infections with overly broad-spectrum antibiotics, can contribute to the increase of drug-resistant S. pneumoniae in a population. 1 There is also the problem of treatment failures occurring when infections caused by resistant strains are treated with ineffective antibiotics. 10 Surveillance of emerging infections such as drug-resistant S. pneumoniae is an integral part of preventing and controlling the spread of disease. Prevalence data obtained 2 by surveillance programs can identify changing patterns of resistance and be used by public health officials to develop interventions for specific communities or regions. 11 These interventions include issuing guidelines for appropriate antimicrobial treatment, identifying populations at risk for transmission of drug-resistant S. pneumoniae, and making recommendations concerning pneumococcal vaccination. Prior to 1993, little was known about the prevalence of drug-resistant S. pneumoniae in Connecticut or in other parts of the United States. Working with the Connecticut Department of Public Health (CDPH), I conducted a survey of all hospitals with clinical microbiology laboratories in Connecticut to determine the prevalence of penicillin resistance among isolates of S. pneumoniae in 1992-1993. 15 To determine whether the prevalence of resistant S. pneumoniae has increased since this first laboratory survey was conducted, active hospital laboratory-based surveillance for invasive S. Program (EIP), which is a collaboration between the CDPH and the Centers for Disease Control and Prevention (CDC). The collection of antimicrobial resistance data by a hospital laboratory-based surveillance program depends on the ability of hospital laboratories to accurately detect resistant isolates. However, there have been …