[Study of confirmed cases of human brucellosis in Puebla, Mexico]. / Estudio de casos confirmados de brucelosis humana en Puebla, México.

BACKGROUND: Human brucellosis is a global health problem. Mexico is one of the main countries affected; timely diagnosis and serological tests are the basis for detection. AIM: To know the frequency of confirmed cases of brucellosis in different of Family Medicine Units of the Mexican Social Security Institute in the state of Puebla, Mexico. METHODS: Cross-sectional study in patients of both genders, adults and pediatrics, with clinical manifestations suggestive of brucellosis; serological tests were performed for the confirmatory diagnosis. RESULTS: Out of a total of 77 patients, 39 (50.6%) were positive, 21 (27.3%) cases coming out of infection, 9 (11.7%) were negative and 8 (10.4%) were defined with immunological memory; of positive cases, 32 (82.1%) were found in the adult group and 30 (76.9%) were female. CONCLUSION: Around half of samples were confirmed as brucellosis, the clinical manifestations of the patients studied were non-specific, which highlights the importance of laboratory diagnosis.

Estudio de casos confirmados de brucelosis humana en Puebla, México / Study of confirmed cases of human brucellosis in Puebla, Mexico

INTRODUCCIÓN: La brucelosis humana es un problema zoo-sanitario global. México es uno de los principales países que se ven afectados, el diagnóstico oportuno y las pruebas serológicas confirmatorias son la base para la detección. OBJETIVO: Conocer la frecuencia de casos confirmados de brucelosis en diferentes Unidades de Medicina Familiar del Instituto Mexicano del Seguro Social en el estado de Puebla, México. PACIENTES Y MÉTODOS: Estudio transversal en pacientes de ambos sexos, adultos y pediátricos, con manifestaciones clínicas sugestivas de brucelosis; se realizaron pruebas serológicas para el diagnóstico confirmatorio. RESULTADOS: De un total de 77 pacientes, se obtuvieron 39 (50,6%) casos positivos, 21 (27,3%) casos saliendo de la infección, 9 (11,7%) negativos y 8 (10,4%) con memoria inmunológica; de los casos positivos, 32 (82,1%) eran adultos y 30 (76,9%) fueron del género femenino. CONCLUSIÓN: Del total de muestras, la mitad tuvo diagnóstico de brucelosis, las manifestaciones clínicas de los pacientes estudiados fueron inespecíficas, lo cual resalta la importancia del diagnóstico de laboratorio.

BACKGROUND: Human brucellosis is a global health problem. Mexico is one of the main countries affected; timely diagnosis and serological tests are the basis for detection. AIM: To know the frequency of confirmed cases of brucellosis in different of Family Medicine Units of the Mexican Social Security Institute in the state of Puebla, Mexico. METHODS: Cross-sectional study in patients of both genders, adults and pediatrics, with clinical manifestations suggestive of brucellosis; serological tests were performed for the confirmatory diagnosis. RESULTS: Out of a total of 77 patients, 39 (50.6%) were positive, 21 (27.3%) cases coming out of infection, 9 (11.7%) were negative and 8 (10.4%) were defined with immunological memory; of positive cases, 32 (82.1%) were found in the adult group and 30 (76.9%) were female. CONCLUSION: Around half of samples were confirmed as brucellosis, the clinical manifestations of the patients studied were non-specific, which highlights the importance of laboratory diagnosis.

Characterization of SP41, a surface protein of Brucella associated with adherence and invasion of host epithelial cells.

Brucella is an invasive organism that multiplies and survives within eukaryotic cells. The brucellae are able to adhere to the surface of cultured epithelial cells, a mechanism that may facilitate penetration and dissemination to other host tissues. However, no adhesins that allow the bacteria to interact with the surface of epithelial cells before migration within polymorphonuclear leukocytes, monocytes and macrophages have been described. Here, we show that Brucella surface proteins (SPs) with apparent molecular masses of 14, 18 and 41 kDa bound selectively to HeLa cells. However, only antibodies directed against the 41 kDa surface protein (SP41) inhibited in dose-response manner, bacterial adherence and invasion of HeLa cells. HeLa cells treated with neuraminidase did not bind SP41, suggesting the involvement of cellular sialic acid residues in this interaction. Biochemical analysis of SP41 revealed that this protein is the predicted product of the ugpB locus, which showed significant homology to the glycerol-3-phosphate-binding ATP-binding cassette (ABC) transporter protein found in several bacterial species. SP41 appears to be exposed on the bacterial surface as determined by immunofluorescence and immunogold labelling with anti-SP41 antibody. An isogenic DeltaugpB mutant showed a significant inhibitory effect on Brucella adherence and invasion of human cultured epithelial cells and this effect could be reversed by restoration of the ugpB on a plasmid. Lastly, we also show that most of the sera from individuals with acute brucellosis, but not sera obtained from healthy donors or patients with chronic brucellosis, mount antibody reactivity against SP41, suggesting that this protein is produced in vivo and that it elicits an antibody immune response. These data are novel findings that offer new insights into understanding the interplay between this bacterium and host target cells, and identify a new target for vaccine development and prevention of brucellosis.

Adherence of Brucella to human epithelial cells and macrophages is mediated by sialic acid residues.

The basis for the interaction of Brucella species with the surface of epithelial cells before migration in the host within polymorphonuclear leucocytes is largely unknown. Here, we studied the ability of Brucella abortus and Brucella melitensis to adhere to cultured epithelial (HeLa and HEp-2) cells and THP-1-derived macrophages, and to bind extracellular matrix proteins (ECM). The brucellae adhered to epithelial cells forming localized bacterial microcolonies on the cell surface, and this process was inhibited significantly by pretreatment of epithelial cells with neuraminidase and sodium periodate and by preincubation of the bacteria with heparan sulphate and N-acetylneuraminic acid. Trypsinization of epithelial cells yielded increased adherence, suggesting unmasking of target sites on host cells. Notably, the brucellae also adhered to cultured THP-1 cells, and this event was greatly reduced upon removal of sialic acid residues from these cells with neuraminidase. B. abortus bound in a dose-dependent manner to immobilized fibronectin and vitronectin and, to a lesser extent, to chondroitin sulphate, collagen and laminin. In sum, our data strongly suggest that the adherence mechanism of brucellae to epithelial cells and macrophages is mediated by cellular receptors containing sialic acid and sulphated residues. The recognition of ECM (fibronectin and vitronectin) by the brucellae may represent a mechanism for spread within the host tissues. These are novel findings that offer new insights into understanding the interplay between Brucella and host cells.

Brucella sp. bind to sialic acid residues on human and animal red blood cells.

We report that Brucella abortus and Brucella melitensis agglutinate human (A+ and B+), hamster and rabbit erythrocytes, a heretofore undescribed feature in this genus. This activity was associated with a 29-kDa surface protein (SP29) that bound selectively to these erythrocytes and this binding was inhibited by rabbit anti-SP29 antibodies. Hemagglutination was inhibited by pretreatment of erythrocytes with neuraminidase and by preincubation of B. abortus with chondroitin sulfate, N-acetylneuraminic acid and N-acetylneuramin-lactose.