INFECTIVE ENDOCARDITIS IN PATIENTS WITH NEGATIVE BLOOD CULTURES - ANALYSIS OF 88 CASES FROM A ONE-YEAR NATIONWIDE SURVEY IN FRANCE

Flood cultures were negative in 88 (14%) of 620 cases of infective end ocarditis (IE) documented in France during a 1-year nationwide survey. In 15 of these 88 cases, the causative microorganism was identified: seven cases of Q fever endocarditis and two cases of chlamydial endoca rditis were diagnosed by serological and/or immunohistologic technique s, and a pathogen was cultured from five surgically removed valves and one arterial septic embolus. Forty-two (48%) of the 88 cases involved patients who had received antibiotics before the first blood sample w as taken for culture. Mortality was lower in this group than among pat ients who had not previously received antibiotics (7% vs. 22%, P = .05 ). Comparison of blood culture-negative cases of IE with blood culture -positive cases revealed that the former tended to occur more often on prosthetic valves (32% vs. 22%, P = .16), were more often left-sided (97% vs. 83%, P = .0009), less often included extracardiac symptoms at presentation (52% vs. 63%, P = .06), and were more often surgically t reated (53% vs. 34%, P = .001). Mortality was similar regardless of th e results of blood culture (15% vs. 21%, P = .18). This study showed t hat more than 10% of all cases of IE in France are still associated wi th negative blood cultures and confirmed that a search for pathogens s uch as Coxiella burnetii and Chlamydia species is worthwhile in this s ituation.