315. Healthcare-Associated (HCA) Legionella Disease (LD) in U.S. Department of Veterans Affairs (VA) Medical Centers in 2014:  A New VA National Tracking System Sheds Light on the Impact of a Change in CDC Surveillance Definitions
Session: Poster Abstract Session: HAI: Epidemiology
Thursday, October 8, 2015
Room: Poster Hall
Background: Data are sparse on the contribution of HCA LD to overall LD incidence in the U.S.  This is especially true in the context of new (2014) CDC HCA LD surveillance definitions, which now include outpatient exposure in the 10 days prior to symptom onset as possible HCA LD.  VA has HCA LD prevention policy that includes encouraging diagnosis of LD and epidemiologic determination of infection source.  A new VA national LD tracking system can be used to understand the impact of the CDC definition change on classification of HCA LD.

Methods: An electronic LD Case Report form was developed for use by the 152 VA Medical Centers (VAMCs) across the U.S.  Data fields include, among others: dates of symptom onset and diagnosis, presence of pneumonia signs/symptoms, diagnostic testing, and exposure, if any, to a VAMC within the 10 days prior to symptom onset.  For VAMC association, data fields delineate whether exposure was during inpatient only, outpatient only, or both inpatient and outpatient contact.  LD cases in 2014 were categorized for VAMC association using the old and new definitions to assess impact of the change.     

Results: VAMCs reported 110 LD cases in 2014.  Sixty-two of these cases were community-associated, while 7 cases were definitely HCA LD and 41 met the new CDC definition of possibly HCA LD.  For the 41 possibly HCA LD cases, 4 had only inpatient exposure, 8 had both inpatient and outpatient exposure, and 29 had only outpatient exposure.  Comparing case numbers for old and new definitions, there is no difference in number of total LD cases or of definite HCA LD cases.  However, there is a 242% increase in the number of cases classified as possibly HCA LD using the new 2014 definition and a concomitant 32% decrease in cases designated as community-associated.

Conclusion: The VA tracking system provides the first national look at the impact of the CDC LD surveillance definition changes on healthcare facilities.  With these new definitions, it would appear that VA had a substantial increase in possible HCA LD cases in one year, though the change is due to the shifting of cases that were considered community-associated previously.  Better understanding of LD in the outpatient setting is necessary to determine the validity of the shift in classification and inform prevention decisions.

Shantini Gamage, PhD, MPH1,2, Meredith Ambrose, MHA1, Stephen Kralovic, MD, MPH, FSHEA1,2,3 and Gary Roselle, MD, FIDSA1,2,3, (1)National Infectious Diseases Service, Patient Care Services, Veterans Affairs Central Office, Cincinnati, OH, (2)Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, (3)Cincinnati Veterans Affairs Medical Center, Cincinnati, OH

Disclosures:

S. Gamage, None

M. Ambrose, None

S. Kralovic, None

G. Roselle, None

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