NATIONAL SURVEILLANCE CONFERENCE

CSTE POSITION STATEMENT 1994-NSC-10

COMMITTEE: Executive Committee

TITLE: National Surveillance for Drug-Resistant Streptococcus pneumoniae (DRSP) Invasive Disease

BACKGROUND/JUSTIFICATION: Streptococcus pneumoniae is the most frequent cause of bacterial pneumonia in persons of all ages, the most common cause of bacteremia and acute otitis media in children, and a leading cause of meningitis in the United States. In the U.S., there are an estimated 500,000 cases of pneumococcal pneumonia, 150,000 cases of bacteremia, and 3,000 cases of pneumococcal meningitis; 36,000 deaths from pneumococcal disease occur per year. Hospitalization costs alone exceed $2 billion annually. Young children and the elderly are at greatest risk for pneumococcal infections and complications, and the annual incidence rate of bacteremia is 100-160/100,000 population in children < two years of age and 50-70/100,000 population in adults > 65 years of age. Incidence of pneumococcal infection is greater among persons with chronic illnesses including HIV/AIDS. Non-white persons, especially African Americans, American Indians, and Alaskan Natives are also at increased risk for pneumococcal bacteremia.

Reports of drug-resistant S. Pneumoniae infection (including strains resistant to penicillin, extended spectrum cephalosporins and chloramphenicol) have been increasing in the United States since the 1980's. Limited CDC active surveillance data also document an increase in antibiotic-resistant isolates since 1987. Recent surveys in a few communities show a wide variability in prevalence of drug-resistant S. Pneumoniae infection (range of two to 30 percent of all invasive pneumococcal infections). A substantial proportion of infections in some communities is due to highly resistant and multi-resistant strains.

POSITION TO BE ADOPTED: CSTE recommends:

1) Drug-resistant Streptococcus pneumoniae (DRSP) should be added to the list of conditions under national surveillance in the National Public Health Surveillance System (NPHSS).

2) States and territories should institute surveillance for DRSP to determine the proportion of sterile site SP isolates that are drug resistant., This can be by voluntary submission of existing data or, if resources permit, legally mandated notification of individual patient data from laboratories. States and territories should forward DRSP prevalence information to CDC for the purposed of national surveillance.


3) CSTE, ASTPHLD, CDC, states and territories should work to promote antibimicrobial susceptibility testing in accordance with guidelines from the National Committee for Clinical Laboratory Standards (NCCLS) for cerebrospinal fluid and blood isolates.

4) CSTE, CDC, states and territories should work to provide surveillance information to health care providers about the prevalence of DRSP in specific geographic areas and to develop and implement prevention and control strategies.

5) Any computer software developed by CDC to support this surveillance system should be able to produce a data file that is fully compatible with existing NETSS and PHLIS software.

6) Surveillance data on DRSP should be published on a regular basis in the MMWR.

GOALS FOR SURVEILLANCE: The purpose of the surveillance system is to define and monitor the prevalence and geographic distribution of drug-resistant Streptococcus pneumoniae and rapidly recognize the emergence of new patters of resistance. The primary goal is to control and prevent the further spread and deleterious public health consequences of DRSP.

Population-based laboratory surveillance designed to detect invasive drug-resistant pneumococcal infections is necessary to provide data to accomplish this goal. The specific outcome objectives to control and prevent the spread of DRSP include: 1) more judicious use of antibiotics, 2) more appropriate antibiotic choices for empiric therapy of presumed pneumococcal disease, 3) increased and more targeted vaccine utilization, 4) identification of regions with high resistance needing further epidemiologic investigation, and 5) decreased pneumococcal illness, excessive complications, health care expenditures, and mortality due to pneumococcal disease. 

The information from a surveillance system could be utilized in the following ways for prevention and control of drug-resistant S. Pneumoniae infections. First, since inappropriate use of antibiotics is linked to increases in pneumococcal antibiotic resistance, data regarding community-wide levels of antibiotic resistance can be used to target certain communities for promotion of more judicious use of antibiotics. Second, the Advisory Committee on Immunization Practices (ACIP) recommends that persons aged > two years who are at increased risk for serious pneumococcal disease, and all persons aged > 65 years should receive the 23-valent pneumococcal vaccine; yet the vaccine has been under-utilized. Information defining pneumococcal antibiotic resistance levels will be very useful for targeting communities for intensified vaccination programs and for monitoring the effects of new (protein-conjugate) and existing pneumococcal vaccines.


While the prevalence of drug-resistant S. Pneumoniae infection appears to be increasing in the United States, the magnitude and geographic distribution of the problem are not known. Prior to the emergence of drug-resistant S. Pneumoniae, most pneumococcal infections were treated empirically with penicillin or other beta-lactam drugs. Surveillance data are now needed to identify areas with high rates of drug-resistant pneumococci to allow clinicians to better select empiric antimicrobial drug therapy for pneumococcal infections and allow public health officials to monitor national trends in resistance patterns. Such information may be useful for targeting selected areas for vaccine promotion campaigns, and potentially for restricting or regulating the use of certain antimicrobial agents.

Hypotheses generated by surveillance data will also be useful to guide future research. Investigations in areas with high proportions of resistant pneumococcal isolates can be used to determine the clinical and economic impact of drug-resistant pneumococcal infections and to better characterize the epidemiology of the disease, including risk factors. In addition, new formulations of pneumococcal protein-conjugate vaccines may be elevated for prevention of infections in children in areas with high proportions of drug-resistant pneumococci.

METHOD OF SURVEILLANCE: Laboratory surveillance for invasive drug-resistant pneumococcal infections should be population-based. Microbiology laboratories should report antimicrobial susceptibility data for all isolates of S. Pneumoniae cultured from cerebrospinal fluid and blood specimens to their state or territorial health departments.

CASE DEFINITION:

Drug-Resistant Streptococcus pneumoniae Invasive Disease

Clinical description:

Pneumococci may cause a wide variety of clinical syndromes depending on the site of infection (e.g., otitis media, pneumonia, bacteremia, meningitis). For the purposes of national surveillance, “invasive” pneumococcal disease shall refer only to bacteremia and/or meningitis. Although S. Pneumoniae infections involving other normally sterile sites such as joint, pleural, or peritoneal fluid are sometimes considered invasive, these infections are not intended for inclusion under this surveillance system.

Laboratory criteria for diagnosis:

1. Isolation of S. Pneumoniae from blood or cerebrospinal fluid.
2. Intermediate and high level resistance (defined by NCCLS approved methods and interpretive MIC breakpoints) of the S. Pneumoniae isolate to at least one antimicrobial agent currently approved for use in treating pneumococcal infections1.

Case Classification: 

Probable: A clinically compatible case due to laboratory-confirmed culture of S. Pneumoniae identified as “non-susceptible” (i.e., oxacillin zone size < 20 mm) when oxacillin screening is the only method of antimicrobial susceptibility testing performed.

Confirmed: A clinically compatible case due to laboratory-confirmed S. Pneumonia identified as “non-susceptible” according to MIC interpretive breakpoints as outlined in NCCLS guidelines .

for susceptibility testing to any antimicrobial agent currently approved for use in treating pneumococcal infections1.


Comment

NCCLS recommends that all invasive S. Pneumoniae isolates which are found to be “possibly resistant” to beta-lactams (oxacillin zone size < 20 mm) by oxacillin screening should undergo further susceptibility testing using a quantitative MIC method acceptable for penicillin and extended spectrum cephalosporins, and other drugs as clinically indicated.

1Minimum Inhibitory Concentration (MIC) Interpretive Standard (ug/ml) for S. Pneumoniae; NCCLS Guidelines 1994.

Data to be Collected:

Minimum data collected from the laboratories if individual cases are reported would include: name, age or birth date, anatomic site of the isolate, the antibiotic susceptibility pattern, and unique identifiers for the lab and the specimen. Aggregate laboratory reporting would, at a minimum, summarize data by age group.

Period for Surveillance: Permanent

CONSULTATION WITH OTHER ORGANIZATIONS: CDC, ASTHO, ASTHPHLD

CONTACT: CSTE: Executive Committee

CDC: Marty Cetron, M.D.
National Center for Infectious Diseases, MS F22
Centers for Disease Control and Prevention
1600 Clifton Road
Atlanta, GA 30333
404-639-3052