Laboratory diagnosis and serologic evolution of patients with tularemia

BACKGROUND: Tularemia was practically unknown in Spain until the end of 199 7, when an epidemic outbreak was declared. This paper presents the data on microbiological diagnosis of 55 patients who suffered from tularemia, PATIENTS AND METHODS: Thirty-two samples from 19 patients and 151 serum sam ples from 55 patients were obtained for culture. Serologic diagnosis was pe rformed by tube seroagglutination and microagglutination. Three types of te sts were performed on all sera: Wright seroagglutination (WSA), Coombs test against Brucella spp, and seroagglutination against Yersinia enterocolitic a O:3, Yersinia enterocolitica O:3, and Proteus OX 19, RESULTS: F. tularensis was found in two samples (6.25%) of the 32 received. Titers greater than or equal to 1/160 were obtained in 78.2% and 74.5% of the initial sera by tube seroagglutination and microagglutination, respecti vely. Correlation between the two tests was 0.80 (p < 0.001). Prozone pheno menon was observed in 59.9% of the sera, while crossed reactivity to Brucel la spp, and Proteus spp. was found in 9.3% and 22.8%, respectively. No cros sed reactivity was observed with Yersinia spp. CONCLUSIONS: Culture of F. tularensis has low sensitivity. The correlation obtained between tube seroagglutination and microagglutination is good. Bot h techniques are useful in routine diagnosis of tularemia, although microag glutination has some advantages over tube agglutination.