Motivation and Rationale. Public health officials investigate outbreaks to prevent additional illness, and to learn how to prevent outbreaks. Pulsed-field gel electrophoresis (PFGE) analysis, a molecular laboratory technique examining DNA fingerprints, can aid in epidemiological investigation by providing DNA evidence for detecting outbreak-related cases among apparently unrelated cases.
Limited resources require state and local health departments to prioritize investigations of PFGE-identified clusters. The only guidance is CDC’s advice to investigate all PFGE-identified clusters.
Only one study, conducted in Minnesota, has researched the characteristics of Salmonella and E.coli clusters that predict their being solved. Minnesota centralizes their PFGE cluster investigations and has a different demographic composition than New York State (NYS). It is unclear if the results in the Minnesota study are generalizable to states, such as New York, that have a decentralized management system for cluster investigations. To assess this, NYS data were analysed and compared with the results from the Minnesota study.
Research Question. What factors of clusters are associated with solving Salmonella and E.coli PFGE clusters in NYS outside of NYC between 2008 and 2012?
Methods. This study included NYS outside of NYC residents who were part of a Salmonella or E. coli cluster identified by the NYS Department of Health (DOH) Wadsworth Center (WC) between 2008 and 2012. A cluster was defined as two or more cases with isolates of the same serotype, PFGE subtype, and specimen collection dates within 60 days of each other. A cluster was considered solved if the epidemiologic evaluation of that cluster resulted in the identification of a common source of infection for those cases.
Results. Salmonella clusters which consisted of three cases or more were more likely to be solved than clusters of two. Also, Salmonella clusters in which the first three cases were received within a week of each other were more likely to be solved than clusters where the first three cases were received more than two weeks apart. Insufficient data exist for a complete analysis of E. coli at this time.
Conclusions. The NYS data suggest that prioritizing Salmonella PFGE cluster investigations based on the number of cases received and on cluster-case density optimizes solving clusters. These findings are similar to those of the Minnesota study and therefore appear to be applicable to states with either centralized or de-centralized investigation management. Based on both studies, limited resources require public health to refine the criteria for prioritizing cluster investigations.
|Commitee:||Musser, Kimberlee, Smith, Perry|
|School:||State University of New York at Albany|
|School Location:||United States -- New York|
|Source:||DAI-B 77/11(E), Dissertation Abstracts International|
|Subjects:||Public health, Epidemiology|
|Keywords:||Escherichia coli, Evaluation, New York, Outbreak, PFGE, Pulsed-field gel electrophoresis, STEC, Salmonella|
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