High prevalence of Bartonella quintana endocarditis in Sfax, Tunisia.

Bartonella quintana is a fastidious microorganism associated with blood culture negative endocarditis. In this study, 40 sera with cross-reactivity between Chlamydia species from patients from Sfax, Tunisia, were serologically tested for Bartonella. Thirteen sera were positive for Bartonella with IgG titers >/=1:800. Western blot and cross-absorption confirmed the diagnosis of Bartonella quintana endocarditis in 12 cases and Bartonella henselae endocarditis in 1 case. These sera were also positive by LightCycler nested PCR amplification for the rnpb (7 of 13) and fur (11 of 13) genes. Eleven patients had a definite diagnosis of endocarditis, which represents 9.8% of all endocarditis. Because Bartonella endocarditis seems to be very common in Tunisia, we suggest that its serology be performed systematically whenever endocarditis is suspected.