Influenza A Virus PB1-F2 Gene

Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 10, October 2006 1607 biologic results. Since both strains were identified as L. pneumophila serogroup 1, we performed sequencebased typing (SBT) (3) of 6 genes (flaA, pilE, asd, mip, mompS, and proA) by using the protocol and database of EWGLINET. Both isolates showed identical SBT patterns (2,3,18,15,2,1). Isolates from 4 patients in the Zaragoza outbreak were identified at the Spanish Reference Laboratory as L. pneumophila serogroup 1 (Philadelphia monoclonal antibody type) and had identical SBT patterns (3,4,1,1,14,9). Collaboration between public health authorities in France and Spain enabled us to eliminate the association of patient 2 with the Zaragoza outbreak and establish an association of both patients with the same site in France. Control measures were taken at the hotel, but we could not obtain environmental cultures for comparison with those of the patients. Lack of environmental data prevented investigation of the relationship with the other accommodation sites visited. The SBT method provides robust genotyping with high discriminatory power (index of discrimination >0.94) (3). This method is less effective at discriminating between strains than pulsed-field gel electrophoresis (4), but it shows excellent reproducibility and may be useful in epidemiologic investigation of outbreaks caused by L. pneumophila. The availability of an online database with accessible information is key for sharing results and determining the geographic distribution of isolates that cause Legionnaires’ disease (4,5). This study demonstrates the critical role of sharing results between countries that participate in a network. Agreement is essential on a standardized questionnaire that includes more information on the patient’s exposure to a disease. Moreover, despite the performance of the urine antigen test, cultures of clinical samples should be encouraged by clinicians and microbiologists. This step would permit use of techniques, such as SBT, in reference laboratories and sharing of results. Our investigation would have been more difficult without this technique in identifying the site where the infection potentially originated.