Laboratory diagnosis of brucellosis in a rural endemic area in northeastern Spain

Sera obtained from 62 patients from four mountain counties in Catalonia (Northeastern Spain), in whom brucellosis had been diagnosed on the basis of clinical evidence and/or personal history, were analyzed using the rose Bengal test, standard serum agglutination test (SAT), Coombs" test, ELISA, and complement fixation. The diagnosis was further confirmed through blood cultures. Clinical evidence, epidemiology, and the results from serologic tests were used to assign patients to one of two groups: group 1 (n = 38) patients had primary infections, whereas group 2 (n = 24) patients had been previously exposed to the microorganism, i.e. re-infection of group 2 individuals occurred after long periods of time during which no active infection by Brucella had been detected. Receivingoperating charts (ROC) were used to determine the diagnostic value of the different tests and to establish discriminant values. Blood culture was a valuable diagnostic tool in group 1 (0.92 sensitivity) but was inappropriate in group 2 (0.08). The combination of positive rose Bengal test and agglutination ≥1/160 was valid for diagnosis in group 1. In group 2, agglutination < 1/160 (including negative agglutination) did not rule out brucellosis. The combination of positive rose Bengal test and Coombs" test ≥1/320 was the best diagnostic criterion (0.8 specificity; 1 sensitivity). ELISA (for IgG, IgM, or both) did not improve diagnostic accuracy

The Rose Bengal test in human brucellosis: a neglected test for the diagnosis of a neglected disease

Brucellosis is a highly contagious zoonosis affecting livestock and human beings. The human disease lacks pathognomonic symptoms and laboratory tests are essential for its diagnosis. However, most tests are difficult to implement in the areas and countries were brucellosis is endemic. Here, we compared the simple and cheap Rose Bengal Test (RBT) with serum agglutination, Coombs, competitive ELISA, Brucellacapt, lateral flow immunochromatography for IgM and IgG detection and immunoprecipitation with Brucella proteins. We tested 208 sera from patients with brucellosis proved by bacteriological isolation, 20 contacts with no brucellosis, and 1559 sera of persons with no recent contact or brucellosis symptoms. RBT was highly sensitive in acute and long evolution brucellosis cases and this related to its ability to detect IgM, IgG and IgA, to the absence of prozones, and to the agglutinating activity of blocking IgA at the pH of the test. RBT was also highly specific in the sera of persons with no contact with Brucella. No test in this study outperformed RBT, and none was fully satisfactory in distinguishing contacts from infected patients. When modified to test serum dilutions, a diagnostic titer >4 in RBT resulted in 87.4% sensitivity (infected patients) and 100% specificity (contacts). We discuss the limitations of serological tests in the diagnosis of human brucellosis, particularly in the more chronic forms, and conclude that simplicity and affordability of RBT make it close to the ideal test for small and understaffed hospitals and laboratories.

Elisa, la mare de la meva mare

La relació mare-filla en la vida de les dones