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| Active Bacterial Core Surveillance |
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| Home > Methodology |
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Methodology
| Case definition |
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A case of invasive bacterial disease is defined as isolation of group A streptococcus, group B streptococcus, Haemophilus influenzae, Neisseria meningitidis, or Streptococcus pneumoniae from a normally sterile site in a resident of one of the surveillance areas. |
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A normally sterile site is defined as: blood, cerebrospinal fluid, pleural fluid, peritoneal fluid, pericardial fluid, surgical aspirate, bone, or joint fluid. |
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Tissue isolates known to have been collected during surgical procedures (e.g., muscle collected during debridement for necrotizing fasciitis) will only be considered sterile sites for group A streptococcus. |
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Isolation of an organism from middle ear, amniotic fluid, placenta, sinus, or wound should only be reported if the organism is also isolated from a normally sterile site.
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Case ascertainment |
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Case finding is active and laboratory-based. Because isolation of one of these organisms from a normally sterile site is essential to the case definition, the microbiology laboratories in acute care hospitals and appropriate reference laboratories processing sterile site specimens for residents of the surveillance area are the sources for case identification. |
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Data that are essential for describing the population-based epidemiology of these diseases (e.g., age, residence within the surveillance area, outcome) are not available in many microbiology laboratories. Therefore, the case identification is complemented by additional data collection to complete a standard case report form.
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| Isolate Collection and Lab Characterization |
| Pathogen |
Test(s) |
| Neisseria meningitidis |
multilocus enzyme electrophoresis, pulsed field gel electrophoresis, and serosubtyping on samples of isolates as part of special projects
antimicrobial susceptibility of periodic samples* |
| Haemophilus influenzae |
all isolates are serotyped (a-f)
evaluation of capsular gene sequence among samples* |
| group A streptococcus |
M-, T-, and emm-typing for all isolates; since 1997, M-typing no longer performed.
pulsed field gel electrophoresis and sof sequence typing of subsets*
antimicrobial susceptibility of samples* |
| group B streptococcus |
serotyping for interested surveillance areas (eg, GA, MD, OR, NY)
antimicrobial susceptibility of samples* |
| Streptococcus pneumoniae |
antimicrobial susceptibility testing for all invasive isolates (either at CDC, contract lab, or Minnesota)
serotyping of all invasive isolates since January 1, 1998
genotyping certain groups of ABCs isolates (pulsed field gel electrophoresis, multilocus sequence typing, penicillin binding protein gene and dhf gene-specific restriction fragment length polymorphism/sequence analysis) |
| * Studies conducted in collaboration with diverse investigators outside CDC Respiratory Diseases Branch and Meningitis and Special Pathogen Branch |
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| Case Report Form |
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Date: May 22, 2006
Content source: National Center for Immunization and Respiratory Diseases / Division of Bacterial Diseases |
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