Bartonella, Molecular Detection, PCR
Diagnosing Bartonella infection
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Bartonella henselae and Bartonella quintana are small, pleomorphic, Gram-negative bacilli that are difficult to isolate by culture due to their fastidious growth requirements. Bartonella henselae has been associated with cat scratch disease, bacillary angiomatosis, peliosis hepatitis, and endocarditis. Bartonella quintana has been associated with trench fever, bacillary angiomatosis, and endocarditis.
The diagnosis of Bartonella infection has traditionally been made by Warthin-Starry staining of infected tissue and and/or serology. However, these methods may be falsely negative or nonspecific, respectively. Culture is insensitive.
Evaluation of infected tissue using PCR has been shown to be an effective tool for diagnosing Bartonella infection. Mayo Medical Laboratories has developed a real-time PCR test that permits rapid identification of Bartonella species. The assay targets a unique sequence of the citrate synthase gene present in Bartonella species.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
A positive test indicates the presence of Bartonella species DNA.
A negative test indicates the absence of detectable DNA, but does not negate the presence of the organism or recent disease as false negative results may occur due to inhibition of PCR, sequence variability underlying primers and/or probes, or the presence of Bartonella DNA in quantities less than the limit of detection of the assay.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test does not differentiate between Bartonella henselae and Bartonella quintana. A negative result indicates the absence of detectable Bartonella DNA in the specimen but does not negate the presence of organism or active or recent disease and may occur due to inhibition of PCR, sequence variability, underlying primers and/or probes, or the presence of Bartonella species in quantities less than the limit of detection of the assay. Inhibition of <2% has been noted in formalin-fixed paraffin-embedded tissues. In a study of 178 ocular fluids, no inhibition was detected, although this is a possibility due to the relatively small number of specimens tested.
BART/81575 Bartonella Antibody Panel, IgG and IgM, Serum and/or 9943 Warthin-Starry Stain of tissue should be considered if PCR is negative and there is a strong suspicion of disease caused by these organisms.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Karem KL, Paddock CD, Regnery RL: Bartonella henselae, B. quintana, and B. bacilliformis: historical pathogens of emerging significance. Microbes Infect 2000 August;2(10):1193-1205
2. Agan BK, Dolan MJ: Laboratory diagnosis of Bartonella infections. Clin Lab Med 2002 December;22(4):937-962
3. Maguina C, Gotuzzo E: Bartonellosis. New and old. Infect Dis Clin North Am 2000 March;14(1):1-22
4. Vikram HR, Bacani AK, Devaleria PA, et al: Bivalvular Bartonella henselae prosthetic valve endocarditis. J Clin Microbiol 2007 December;45(12):4081-4084
5. Lin EY, Tsigrelis C, Baddour LM, et al: Candidatus Bartonella mayotimonensis and endocarditis. Emerg Infect Dis 2010 Mar;16(3):500-503