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Bacterial Meningitis in the United States, 1986: Report of a Multistate Surveillance Study Jay D. Wenger, Allen W. Hightower, Richard R. Facklam, Suzanne Gaventa, Claire V. Broome, and the Bacterial Meningitis Study Group*
From the Meningitis and Special Pathogens and Respiratory and Special Pathogens Branches and Statistical Services Activity, Division of Bacterial Diseases, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia
Bacterial meningitis and other invasive bacterial diseases remain major causes of morbidity and mortality in the USA, especially in children. Accurate information on pathogenic agents, the population at risk, and case fatality rates is critical for planning effective public health measures. Issues of particular importance include appropriate use of available vaccines for disease caused by Haemophilus injiuenzae and Streptococcus pneumoniae, trends in antibiotic resistance (especially ampicillin resistance in H. injiuenzae), and identification of groups who may be at particularly high risk of disease (by race, sex, age, or other characteristics) and who therefore should be the target of more aggressive preventive measures. Several studies published in the early- to mid-1970s established the characteristic epidemiology of bacterial meningitis in the USA through intensive case finding efforts in relatively small populations [1-4]. Schlech et al. [5] later provided an overview of bacterial meningitis in this country by analyzing surveillance data voluntarily supplied by state and local health departments from 1978 through 1981. Although that study included data for 4 years from 29 states, significant underreporting occurred because there was no active effort to detect cases. In addition to underestimates of rates of disease, if the underreporting was selective, the resulting bias may have led to erroneous estimates of causative or-
Received 20 March 1990; revised 11 June 1990.
Reprintsor correspondence: Dr. Jay D. Wenger, Bldg. 1, Room 5409, COO, Centers for Disease Control, Atlanta, GA 30333. • Study group members are listed after the text. The Journal of Infectious Diseases 1990;162:1316-1323 This article is in the public domain. 0022-1899/90/6206-(XH4
ganisms, population at risk, and outcome. Studies of incidence and characteristics of disease due to single organisms have since appeared, but none have evaluated meningitis or invasive bacterial disease in a large population to assess the relative importance of the multiple organisms that can cause these syndromes. During 1986, six state and local health departments in collaboration with the Centers for Disease Control (CDC) performed active, laboratory-based surveillance for all cases of meningitis and for invasive bacterial disease caused by the five most common causes of bacterial meningitis (H. injiuenzae, S. pneumoniae, Neisseria meningitidis, group B streptococcus, and Listeria monocytogenes). Sensitivity was evaluated by review of discharge diagnoses and laboratory audits. This report summarizes our findings in a population of 34 million people.
Methods Surveillance for invasive disease due to H. irfiuenzae, N. meningitidis, S. pneumoniae, L. monocytogenes, and group B streptococcus was performed in five states (Missouri, New Jersey, Oklahoma, Tennessee, and Washington) and Los Angeles County, CA, from 1 January to 31 December 1986. A case of invasive disease was defined as an illness in which one of these organisms was isolated from a normally sterile site (e.g., blood, cerebrospinal fluid [CSF] , peritoneal fluid). In addition, reports were requested for all cases with CSF cultures growing any other bacterial species. In each of the six surveillance areas, a surveillance coordinator identified a contact person in each hospital or clinical laboratory in the area. The contact was either an infection control practitioner or a microbiology staff member who was responsible for completing a case report form with information on basic demographic characteristics, clinical syndrome, and organism characteristics for each
Downloaded from http://jid.oxfordjournals.org/ at UQ Library on July 12, 2015
A prospective, laboratory-based surveillance project obtained accurate data on meningitis in a population of 34 million people during 1986. Haemophilus inftuenzae was the most common cause of bacterial meningitis (45%), followed by Streptococcus pneumoniae (18%), and Neisseria meningitidis (14%). Ratesof H. inftuenzae meningitis varied significantly by region, from 1.91100,000 in New Jersey to 4.0/100,000 in Washington state. The overall case fatality rates for meningitis were lower than those reported in several studies from the early 1970s, suggesting that improvements in early detection and antibiotic treatment may have occurred since that time. Concurrent surveillance was also performed for all invasive disease due to the five most common causes of bacterial meningitis. Serotypes of group B streptococcus other than type III caused more than half of neonatal group B streptococcal disease and mortality, suggesting that an optimal vaccine preparation must be multivalent. Of the organisms evaluated, group B streptococcus was the second most common cause of invasive disease in persons >5 years old.
JID 1990;162 (December)
Bacterial Meningitis in the USA
Results Sensitivity of active surveillance for disease caused by H. injluenzae, N. meningitidis, and L. monocytogenes as determined by dischargediagnosis code reviewwas 88% or better for each organism. The laboratory audits in Oklahoma and New Jersey confirmed the high sensitivity of active surveillance for these organisms,but demonstratedlower sensitivity for S. pneumoniae and group B streptococcus. In Oklahoma,
Table 1. Total cases of bacterial meningitis and overall case fatality rate by organism.
Organism
H. influenzae S. pneumoniae N. meningitidis
Group B streptococcus L. monocytogenes Other
Cases reported
% of
964 379 293 122 69 331
45 18 14 5.7 3.2 15
total
Incidence Case (cases/ fatality 100,000) rate (%) 2.9 1.1 0.9 0.4 0.2 1.0
3 19 13 12 22 18
sensitivityof active surveillancewas 85 % for S. pneumoniae and 75 % for group B streptococcus; in New Jersey, the sensitivity of active surveillancefor S. pneumoniaewas 59 % and sensitivity for group B streptococcus was 42 %. An estimate of the actual number of cases of disease caused by the two organisms was made by applying the sensitivity of active surveillance (as determined by the laboratory audit) in hospitals that were audited to hospitals of the same size strata that were not audited. Hospitals were stratifiedby number of hospital beds «100, 100-299, or >299 for Oklahoma and 6 mo 8 14 13 13
(11) (19) (18) (18)* 7 (10)
17 (24) 72
proportion of type III in neonates with disease. proportion of type III in infants with disease.
gens but showed an early nadir and rates began to increase in the 10-19-year-old cohort. Surveillance was not performed for nonmeningitic forms of disease due to other organisms. Discussion The present study was an effort to collect accurate surveillance data with a high degree of sensitivity in a large, multistate area. The participating surveillance areas represented several regions and a population of 33.5 million, 14% of the US population at the time of the study. The racial distribution of the surveillance population was similar to that of the USA as a whole. To the extent to which the surveillance population was representative of the entire US population, the results of this study may be generalized. The overall rates for meningitis found in this study were two to three times that noted by Schlech et al. [5], whose study likely had underreporting of meningitis cases due to the voluntary reporting system. The active surveillance system detected "-'90% of cases of invasive disease caused by H. injiuenzae, N. meningitidis, and L. monocytogenes identified in the same
5 years - 30 years- 60 29 years 59 years
years-
population by discharge diagnosis review, suggesting that the sensitivity of the system was good for these organisms. The sensitivity of our surveillance system for nonmeningitic disease caused by group B streptococcus and pneumococcus was not as high as for the other organisms; however, addition of the laboratory audit cases substantially raised the sensitivity of the system compared to projected rates. The resulting data for Oklahoma and New Jersey provide useful baseline estimates of disease incidence and patient characteristics for culture-proven invasive disease caused by these organisms. Compared with the active surveillance studies in the early 1970s (table 6), our data suggest that the incidence of bacterial meningitis has not increased and may be decreasing slightly. We found regional differences in rates of H. infiuenzae meningitis. Although some variation in sensitivity of the various state surveillance operations may have existed, similar rates of meningitis caused by other organisms (e.g., S. pneumoniae) suggest that real geographic differences in incidence of H. infiuenzae disease may exist. Murphy et al. [6] have shown similar variation in rates of H. influenzae disease in children
Bacterial Meningitis in the United States, 1986: Report of a Multistate Surveillance Study Jay D. Wenger, Allen W. Hightower, Richard R. Facklam, Suzanne Gaventa, Claire V. Broome, and the Bacterial Meningitis Study Group*
From the Meningitis and Special Pathogens and Respiratory and Special Pathogens Branches and Statistical Services Activity, Division of Bacterial Diseases, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia
Bacterial meningitis and other invasive bacterial diseases remain major causes of morbidity and mortality in the USA, especially in children. Accurate information on pathogenic agents, the population at risk, and case fatality rates is critical for planning effective public health measures. Issues of particular importance include appropriate use of available vaccines for disease caused by Haemophilus injiuenzae and Streptococcus pneumoniae, trends in antibiotic resistance (especially ampicillin resistance in H. injiuenzae), and identification of groups who may be at particularly high risk of disease (by race, sex, age, or other characteristics) and who therefore should be the target of more aggressive preventive measures. Several studies published in the early- to mid-1970s established the characteristic epidemiology of bacterial meningitis in the USA through intensive case finding efforts in relatively small populations [1-4]. Schlech et al. [5] later provided an overview of bacterial meningitis in this country by analyzing surveillance data voluntarily supplied by state and local health departments from 1978 through 1981. Although that study included data for 4 years from 29 states, significant underreporting occurred because there was no active effort to detect cases. In addition to underestimates of rates of disease, if the underreporting was selective, the resulting bias may have led to erroneous estimates of causative or-
Received 20 March 1990; revised 11 June 1990.
Reprintsor correspondence: Dr. Jay D. Wenger, Bldg. 1, Room 5409, COO, Centers for Disease Control, Atlanta, GA 30333. • Study group members are listed after the text. The Journal of Infectious Diseases 1990;162:1316-1323 This article is in the public domain. 0022-1899/90/6206-(XH4
ganisms, population at risk, and outcome. Studies of incidence and characteristics of disease due to single organisms have since appeared, but none have evaluated meningitis or invasive bacterial disease in a large population to assess the relative importance of the multiple organisms that can cause these syndromes. During 1986, six state and local health departments in collaboration with the Centers for Disease Control (CDC) performed active, laboratory-based surveillance for all cases of meningitis and for invasive bacterial disease caused by the five most common causes of bacterial meningitis (H. injiuenzae, S. pneumoniae, Neisseria meningitidis, group B streptococcus, and Listeria monocytogenes). Sensitivity was evaluated by review of discharge diagnoses and laboratory audits. This report summarizes our findings in a population of 34 million people.
Methods Surveillance for invasive disease due to H. irfiuenzae, N. meningitidis, S. pneumoniae, L. monocytogenes, and group B streptococcus was performed in five states (Missouri, New Jersey, Oklahoma, Tennessee, and Washington) and Los Angeles County, CA, from 1 January to 31 December 1986. A case of invasive disease was defined as an illness in which one of these organisms was isolated from a normally sterile site (e.g., blood, cerebrospinal fluid [CSF] , peritoneal fluid). In addition, reports were requested for all cases with CSF cultures growing any other bacterial species. In each of the six surveillance areas, a surveillance coordinator identified a contact person in each hospital or clinical laboratory in the area. The contact was either an infection control practitioner or a microbiology staff member who was responsible for completing a case report form with information on basic demographic characteristics, clinical syndrome, and organism characteristics for each
Downloaded from http://jid.oxfordjournals.org/ at UQ Library on July 12, 2015
A prospective, laboratory-based surveillance project obtained accurate data on meningitis in a population of 34 million people during 1986. Haemophilus inftuenzae was the most common cause of bacterial meningitis (45%), followed by Streptococcus pneumoniae (18%), and Neisseria meningitidis (14%). Ratesof H. inftuenzae meningitis varied significantly by region, from 1.91100,000 in New Jersey to 4.0/100,000 in Washington state. The overall case fatality rates for meningitis were lower than those reported in several studies from the early 1970s, suggesting that improvements in early detection and antibiotic treatment may have occurred since that time. Concurrent surveillance was also performed for all invasive disease due to the five most common causes of bacterial meningitis. Serotypes of group B streptococcus other than type III caused more than half of neonatal group B streptococcal disease and mortality, suggesting that an optimal vaccine preparation must be multivalent. Of the organisms evaluated, group B streptococcus was the second most common cause of invasive disease in persons >5 years old.
JID 1990;162 (December)
Bacterial Meningitis in the USA
Results Sensitivity of active surveillance for disease caused by H. injluenzae, N. meningitidis, and L. monocytogenes as determined by dischargediagnosis code reviewwas 88% or better for each organism. The laboratory audits in Oklahoma and New Jersey confirmed the high sensitivity of active surveillance for these organisms,but demonstratedlower sensitivity for S. pneumoniae and group B streptococcus. In Oklahoma,
Table 1. Total cases of bacterial meningitis and overall case fatality rate by organism.
Organism
H. influenzae S. pneumoniae N. meningitidis
Group B streptococcus L. monocytogenes Other
Cases reported
% of
964 379 293 122 69 331
45 18 14 5.7 3.2 15
total
Incidence Case (cases/ fatality 100,000) rate (%) 2.9 1.1 0.9 0.4 0.2 1.0
3 19 13 12 22 18
sensitivityof active surveillancewas 85 % for S. pneumoniae and 75 % for group B streptococcus; in New Jersey, the sensitivity of active surveillancefor S. pneumoniaewas 59 % and sensitivity for group B streptococcus was 42 %. An estimate of the actual number of cases of disease caused by the two organisms was made by applying the sensitivity of active surveillance (as determined by the laboratory audit) in hospitals that were audited to hospitals of the same size strata that were not audited. Hospitals were stratifiedby number of hospital beds «100, 100-299, or >299 for Oklahoma and 6 mo 8 14 13 13
(11) (19) (18) (18)* 7 (10)
17 (24) 72
proportion of type III in neonates with disease. proportion of type III in infants with disease.
gens but showed an early nadir and rates began to increase in the 10-19-year-old cohort. Surveillance was not performed for nonmeningitic forms of disease due to other organisms. Discussion The present study was an effort to collect accurate surveillance data with a high degree of sensitivity in a large, multistate area. The participating surveillance areas represented several regions and a population of 33.5 million, 14% of the US population at the time of the study. The racial distribution of the surveillance population was similar to that of the USA as a whole. To the extent to which the surveillance population was representative of the entire US population, the results of this study may be generalized. The overall rates for meningitis found in this study were two to three times that noted by Schlech et al. [5], whose study likely had underreporting of meningitis cases due to the voluntary reporting system. The active surveillance system detected "-'90% of cases of invasive disease caused by H. injiuenzae, N. meningitidis, and L. monocytogenes identified in the same
5 years - 30 years- 60 29 years 59 years
years-
population by discharge diagnosis review, suggesting that the sensitivity of the system was good for these organisms. The sensitivity of our surveillance system for nonmeningitic disease caused by group B streptococcus and pneumococcus was not as high as for the other organisms; however, addition of the laboratory audit cases substantially raised the sensitivity of the system compared to projected rates. The resulting data for Oklahoma and New Jersey provide useful baseline estimates of disease incidence and patient characteristics for culture-proven invasive disease caused by these organisms. Compared with the active surveillance studies in the early 1970s (table 6), our data suggest that the incidence of bacterial meningitis has not increased and may be decreasing slightly. We found regional differences in rates of H. infiuenzae meningitis. Although some variation in sensitivity of the various state surveillance operations may have existed, similar rates of meningitis caused by other organisms (e.g., S. pneumoniae) suggest that real geographic differences in incidence of H. infiuenzae disease may exist. Murphy et al. [6] have shown similar variation in rates of H. influenzae disease in children
