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Active Bacterial Core Surveillance

The Active Bacterial Core surveillance (ABCs) program is a core component of the U.S. Centers for Disease Control and Prevention (CDC ABCs) Emerging Infections Programs (EIP), which is a collaboration between CDC, state health departments, and universities. 

Active bacterial core surveillance

On this page:

ABCs Ongoing Surveillance Activities

ABCs conducts surveillance for several pathogens:

The overall objectives are to:

  • Determine the incidence and epidemiologic characteristics of invasive disease due to the above organisms in multiple large diverse U.S. populations.
  • Determine molecular epidemiologic patterns and microbiologic characteristics of public health relevance for isolates causing the above invasive infections.
  • Provide an infrastructure for further research, such as special studies aimed at identifying risk factors for disease and post-licensure evaluation.


  • For group A and group B streptococcus (GAS, GBS), and Streptococcus pneumoniae, microbiology records from all hospital laboratories in the Portland tri-county region (Clackamas, Multnomah, and Washington counties) are audited on a routine basis.
  • For Haemophilus influenzae and Neisseria meningitidis, microbiology records from all hospital laboratories in the state of Oregon are audited on a routine basis.
  • Sterile site isolates are forwarded to the CDC for further testing.
  • Medical records are reviewed for demographic, clinical, and risk factor information.

ABCs Surveillance Data

Active Bacterial Core Surveillance Data

The objective is to determine the incidence and epidemiologic characteristics of invasive disease due to groups A and B streptococcus, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in several large populations.

The ABCs Monthly Surveillance Summary (pdf) reports monthly and year-to-date incidence rates and comparisons to ten-year average rates for the following pathogens.

For disease reporting and data:

ABCs Special Studies

Oregon EIP Active Bacterial Core Surveillance Special Studies

  • Evaluation of Adherence to Guidelines to Prevent Perinatal Infections in Oregon
    The vertical transmission of infections from mother to child is a major cause of newborn morbidity and mortality. Over the past few decades, interventions to prevent the transmission of certain infections during pregnancy and labor and delivery, such as group B streptococcus (GBS), hepatitis B virus (HBV), human immunodeficiency virus (HIV), syphilis, N. gonorrheae, C. trachomatis, and rubella have been implemented to reduce the burden of these diseases among neonates. This report details the findings of an evaluation of prenatal screening and treatment practices in Oregon for these pathogens. Report (pdf)

  • Non-invasive Pneumococcal Pneumonia (SNiPP) Surveillance
    Population-based Surveillance for Non-invasive Pneumococcal Pneumonia (SNIPP) starting at a baseline year (2013) when PCV13 was not routinely recommended for adults and measuring its disease burden in subsequent years after the 2014 ACIP recommendation went into effect. Pneumococcus is the most common cause of pneumonia, and people aged 65 and over are recommended to get a pneumococcal vaccine. A new pneumococcal vaccine, formerly used in children, was approved for use in adults >65 in 2014. The main objective of this project is to evaluate whether use of the new vaccine has lowered rates of pneumonia in adults. In the past, the ABCs program has only collected information about persons with invasive disease, meaning they had positive cultures of pneumococcus found in their blood, spinal fluid, or lung fluid. However, a new test that only requires a urine specimen will now be used to identify patients with pneumococcus, making it easier to find all patients with pneumonia (because not everyone with pneumonia has a positive culture by the other means described). This will be done as part of the routine surveillance already in place in Oregon in the Portland Tricounty area. We also obtain leftover urine specimens from patients that have a urine test positive for pneumococcus, in order to develop a test that will tell specifically which strain of pneumococcus is causing the infection. In that way, they can tell whether each patient's pneumococcal infection was caused by a strain of pneumococcus that is contained in the new vaccine, which will help researchers determine if the new vaccine is working well in adults.

  • Group B Streptococcal immunologic endpoints
    Group B Streptococcus (GBS) is a leading cause of morbidity and mortality in young infants worldwide. Maternal vaccines to protect young infant against invasive GBS are in development. However, it is unlikely that clinical endpoint trials of vaccine effectiveness will be conducted due to the challenges and costs of following large cohorts of pregnant women to observe sufficient numbers of disease endpoints. If immunologic endpoints can be identified, they offer an alternate mechanism for vaccine licensure, but such endpoints have not yet been established using standardized assays. We are participating in a case-control study comparing anti-GBS capsular antibody levels (immunoglobulin G [IgG]) and function in young infants who develop invasive GBS disease (cases) vs. controls exposed to the same GBS serotype to estimate antibody levels associated with meaningful reductions in disease odds. The case population consists of invasive GBS cases ages 0-89 days from 2019-2022 in Centers for Disease Control and Prevention (CDC)’s Active Bacterial Core surveillance (ABCs). Oregon ABCs is enrolling cases only.

To see all Oregon Emerging Infections Program special studies go to EIP special studies

ABCs Publications / Papers / Presentations

Oregon EIP Active Bacterial Core Surveillance Publications

  • Meningococcal Carriage Following a Vaccination Campaign With MenB-4C and MenB-FHbp in Response to a University Serogroup B Meningococcal Disease Outbreak – Oregon, 2015-2016. J Infectious Diseases. 2017 Nov 27; 216(9): 1130-1140. Abstract
  • Evaluation of Mass Vaccination Clinics in Response to a Serogroup B Meningococcal Disease Outbreak at a Large, Public University – Oregon, 2015. J Adolesc Health. 2018 Aug;63(2):151-156. Abstract 
  • Meningococcal Disease in Persons with HIV Reported Through Active Surveillance in the United States, 2009 – 2019. Open Forum Infect Dis. 2024 Jan 4;11(1). Abstract 
  • Multistate analysis of prospective Legionnaires’ disease cluster detection using SaTScan, 2011 – 2015. PLoS One. 2019 May 30;14(5). Abstract 
  • Invasive Meningococcal Disease due to Nongroupable Neisseria meningitis – Active Bacterial Core Surveillance Sites, 2011 – 2016. Open Forum Infect Dis, 2019 May; 6(5). Abstract 
  • Evaluating Household Transmission of Invasive Group A Streptococcus Disease in the United States Using Population-based Surveillance Data, 2013 – 2016. Clin Infect Dis. 2020 Mar 17;70(7):1478-1481. Abstract 
  • Clinical Characteristics and Adverse Clinical Outcomes of Invasive Haemophilus influenzae Serotype a Cases – United States, 2011 – 2015. Clin Infect Dis, 2021 Dec 6: e3670 – e3676 Abstract 
  • Invasive Meningococcal Disease Among People Experiencing Homelessness – United States, 2016 – 2019. J Infect Dis, 2022 Oct 7, 226(Suppl 3): S322-S326 Abstract 
  • University-Based Outbreaks of Meningococcal Disease Caused by Serogroup B, United States, 2013 – 2018. Emerg Infect Dis, 2019 Mar;25(3):434-440. Abstract