Comparison of in-house and commercial slides for detection by immunofluorescence of immunoglobulins G and M against Bartonella henselae and Bartonella quintana.
We compared the sensitivities and specificities of indirect fluorescent antibody tests developed in our laboratory and commercially available from Focus Technologies (FT; formerly MRL Diagnostic) for detection of serum antibodies to Bartonella spp. Serum samples tested were from patients with culture- or PCR-confirmed Bartonella quintana or B. henselae infections causing cat scratch disease (CSD), chronic bacteremia, or endocarditis. At a cutoff titer of 64, the FT test had higher sensitivity than our in-house test in detecting anti-B. henselae immunoglobulin G (IgG) antibodies in CSD patients (91.2 versus 52.9%; P < 0.001). The specificity in serum samples from 85 control patients was, however, lower with the FT test (87%) than with the in-house test (98.8%) (P = 0.002). A cutoff titer of 128 improves the specificity for the FT test but lowers the sensitivity to 85%. For patients infected with B. henselae, our in-house test, but not the FT test, enabled endocarditis to be detected more reliably. With the in-house test, titers of IgG against B. henselae of >/=1,024 were found only in endocarditis patients and not in CSD patients. With the FT test, 19.1% of CSD patients had titers of IgG against B. henselae of >/=1,024 (P < 0.001). Our in-house technique also improved detection of anti-B. quintana antibodies in homeless patients with endocarditis. IgG titers of >/=1,024 were present in 75% of serum samples, but only in 16.7% of serum samples with the FT test (P = 0.004). Since each test has advantages over the other, the serological diagnosis of Bartonella infections would benefit if both tests were used concurrently.
Unité des Rickettsies, CNRS UMR 6020, IFR 48, Faculté de Médecine, Université de la Méditerranée, 13385 Marseille Cedex 05, France.
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D000907:Antibodies, Bacterial / Q000032:analysis*; D016470:Bacteremia / Q000175:diagnosis; D018416:Bartonella henselae / Q000276:immunology*; D018413:Bartonella quintana / Q000276:immunology*; D002372:Cat-Scratch Disease / Q000175:diagnosis*; D002908:Chronic Disease; D004697:Endocarditis, Bacterial / Q000175:diagnosis; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D012680:Sensitivity and Specificity; D014205:Trench Fever / Q000175:diagnosis*
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M