Laboratory Diagnosis of Human Brucellosis

Abstract

SUMMARY The clinical presentation of brucellosis in humans is variable and unspecific, and thus, laboratory corroboration of the diagnosis is essential for the patient’s proper treatment. The diagnosis of brucellar infections can be made by culture, serological tests, and nucleic acid amplification assays. Modern automated blood culture systems enable detection of acute cases of brucellosis within the routine 5- to 7-day incubation protocol employed in clinical microbiology laboratories, although a longer incubation and performance of blind subcultures may be needed for protracted cases. Serological tests, though they lack specificity and provide results that may be difficult to interpret in individuals repeatedly exposed to Brucella organisms, nevertheless remain a diagnostic cornerstone in resource-poor countries. Nucleic acid amplification assays combine exquisite sensitivity, specificity, and safety and enable rapid diagnosis of the disease. However, long-term persistence of positive molecular test results in patients that have apparently fully recovered is common and has unclear clinical significance and therapeutic implications. Therefore, as long as there are no sufficiently validated commercial tests or studies that demonstrate an adequate interlaboratory reproducibility of the different homemade PCR assays, cultures and serological methods will remain the primary tools for the diagnosis and posttherapeutic follow-up of human brucellosis.

Hepatic brucelloma: a rare complication of a common zoonotic disease

“…In cases of chronic and/or localised brucellosis serum agglutination tests revealing high IgG titres offer higher sensitivity compared with blood, bone marrow or pus cultures that are often negative. 21 This supports the theory that the hepatic abscess emerges rather as a result of reactivation of brucellosis in the setting of chronic disease than during acute infection. Still, the use of serum agglutination tests should be interpreted cautiously in areas endemic for brucellosis.…”

Serological and Molecular Detection of Bovine Brucellosis at Institutional Livestock Farms in Punjab, Pakistan

“…The serological examination includes rose bengal plate test (RBPT), enzyme-linked immunosorbent assay (ELISA), serum agglutination test (SAT), complement fixation test (CFT) and milk ring test (MRT) followed by molecular biological investigation, e.g., polymerase chain reaction (PCR), isolation, biochemical identification and molecular typing e.g., multilocus sequence typing (MLST), single nucleotide polymorphism (SNP) and multiple locus variable number tandem repeat analysis (MLVA) etc. [14,15]. Vaccination and treatment of brucellosis in farm animals are not considered 100% safe for human health, hence are forbidden in many countries [7,[16][17][18][19].…”

Proteomics of Brucella: Technologies and Their Applications for Basic Research and Medical Microbiology

“…Thus, the diagnosis of Brucella based on sero-reactors should be handled with extreme caution unless accompanied by bacteriological and molecular diagnosis. Isolation, the classical biotyping and identification of Brucella spp., remains the gold standard for diagnosis, but it is hazardous, laborious, time-consuming and requires well trained personnel [21]. The genus-level identification relies on the classical bacteriological analysis of cultured colonies and DNA-based molecular tools [22].…”