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Active Bacterial Core surveillance (ABCs) is a core component of CDC’s Emerging Infections Programs network (EIP), a collaboration between CDC, state health departments, and universities. ABCs is an active laboratory- and population-based surveillance system for invasive bacterial pathogens of public health importance. For each case of invasive disease in the surveillance population, a case report form with basic demographic information is completed and bacterial isolates are sent to CDC and other reference laboratories for additional laboratory evaluation. ABCs also provides an infrastructure for further public health research, including special studies aiming at identifying risk factors for disease, post-licensure evaluation of vaccine efficacy and monitoring effectiveness of prevention policies.

ABCs was initially established in four states in 1995. It currently operates among 10 EIP sites across the United States, representing a population of approximately 42 million persons. At this time, ABCs conducts surveillance for six pathogens: group A and group B Streptococcus (GAS, GBS), Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, and methicillin-resistant Staphylococcus aureus (MRSA). Additionally, surveillance for legionellosis and enhanced surveillance for pertussis has been ongoing since 2011.

ABCs data have been used to track disease trends, including the decline in pneumococcal disease following the introduction of the pediatric pneumococcal conjugate vaccine and the emergence of serogroup Y meningococcal disease. ABCs has also contributed to public health policy by providing information which formed the basis of revised CDC guidelines recommending the use of universal screening of pregnant women to prevent early onset GBS infections and the prevention of GAS infections among household contacts of persons with invasive disease and among postpartum and post-surgical patients. A program to assist state and local health departments with surveillance for MRSA and drug-resistant Streptococcus pneumoniae has been developed, based primarily on lessons learned from ABCs.