Bartonella henselae and Bartonella quintana antigens grown in liquid medium are inferior to cell culture-grown antigen for immunofluorescence IgG testing of patient sera.

Serodiagnosis of Bartonella infections predominantly relies on immunofluorescence assays (IFA) utilizing antigen preparations derived from bacteria co-cultivated with host cells. We compared the diagnostic performances of whole-cell Bartonella henselae and Bartonella quintana antigens generated in liquid culture with those from cell culture. IFA using liquid culture-derived B. henselae antigens yielded lower IgG antibody titers, and no consistent correlation in IgG titers was observed for B. quintana. We conclude that liquid-cultured Bartonella antigens are inferior to those used in commercially available diagnostics.IMPORTANCEIn this study, we compare the diagnostic performances of Bartonella henselae and Bartonella quintana antigens cultivated in liquid medium with those of antigens derived from cell culture for use in IFA of patient sera. Our results demonstrate that liquid-cultured Bartonella antigens for IFA are less reliable and may lead to false or missed diagnoses. This highlights the importance of using validated, high-quality antigens to ensure accurate and trustworthy results in clinical practice.