Can Aspergillus fumigatus conidia cause false-positive results in the galactomannan enzyme immunoassay test?

INTRODUCTION: Several factors can cause false-positive results in the galactomannan (GM) test; however, others remain unknown. Presently, the impact of airborne contamination by Aspergillus conidia during enzyme-linked immunosorbent assay (ELISA) remains uninvestigated. METHODS: We studied 12 A. fumigatus isolates. Fungal conidia were serially diluted and tested for GM detection using the Platelia® Aspergillus enzyme immunoassay (EIA). RESULTS: The conidia concentration required for an EIA-positive result was 4.8 × 103 (median). CONCLUSIONS: This is the first study to evaluate the impact of environmental contamination on the Platelia® Aspergillus EIA assay. Only massive contamination can interfere with GM optical readings, suggesting that environmental contamination does not cause false-positive test results.

Can Aspergillus fumigatus conidia cause false-positive results in the galactomannan enzyme immunoassay test?

Abstract INTRODUCTION: Several factors can cause false-positive results in the galactomannan (GM) test; however, others remain unknown. Presently, the impact of airborne contamination by Aspergillus conidia during enzyme-linked immunosorbent assay (ELISA) remains uninvestigated. METHODS: We studied 12 A. fumigatus isolates. Fungal conidia were serially diluted and tested for GM detection using the Platelia® Aspergillus enzyme immunoassay (EIA). RESULTS: The conidia concentration required for an EIA-positive result was 4.8 × 103 (median). CONCLUSIONS: This is the first study to evaluate the impact of environmental contamination on the Platelia® Aspergillus EIA assay. Only massive contamination can interfere with GM optical readings, suggesting that environmental contamination does not cause false-positive test results.

Efficiency of inactive vaccines against contagious agalactia in Brazil / Eficiência de vacinas inativadas contra agalaxia contagiosa no Brasil

This paper aims to evaluate the efficiency of three inactive vaccines against contagious agalactia prepared with samples of Mycoplasma agalactiae isolated in Brazil and different adjuvants. Vaccine 1 adsorbed with aluminum hydroxide was administered in 23 goats (Gc1) and 13 sheep (Gov1); vaccine 2 containing Montanide IMS-2215-VG was administered in 22 goats (Gc2) and 12 sheep (Gov2) and vaccine 3, containing Montanide Gel-01 was administered in 22 goats (Gc3) and 12 sheep (Gov3). All animals were negative for Ma at indirect ELISA and received two doses of 2mL each, subcutaneously, within a 21 day interval. Five animals from each species were used as control. Seventy-five days after the booster, four animals from each vaccinated group and two from the control group were challenged with 5mL of Ma culture containing 10(7)cfu/mL, orally and through immersion of the female's udder in lactation. The serological response was analyzed during vaccination days (0 and 21) and at 51, 81, 111, 141 and 171 days after vaccination. The collection and analysis of the challenged animals were conducted at the day of the challenge (D0) and 7, 14, 21, 28, 35, 42, 49 and 56 days after the challenge. The three vaccines induced the production of antibodies, having no significant statistical difference (p<0.05). Animals from groups Gc1, Gc2 and Gov2 developed higher levels of antibodies, with significant statistical difference compared to the other vaccinated group and control group (p<0.05). After the challenge, the animals from the control presented an increase in regional lymph nodes and conjunctivitis, mastitis and arthritis. In four vaccinated animals, discrete conjunctivitis and congestion of the episcleral veins was observed. It is concluded that vaccines 1 and 2 induced levels of protective antibodies in goats and sheep, sufficient for clinical protection of the animals submitted to the experimental infection, indicating its use on the prevention of contagious agalactia.

Este trabalho tem como objetivo avaliar a eficácia de três vacinas inativadas contra agalaxia contagiosa, preparadas com amostra de Mycoplasma agalactiae isolada no Brasil e diferentes adjuvantes. A vacina 1, adsorvida com hidróxido de alumínio, foi administrada em 23 caprinos (Gc1) e 13 ovinos (Gov1); a vacina 2, contendo Montanide IMS-2215-VG, foi administrada em 22 caprinos (Gc2) e 12 ovinos (Gov2); e a vacina 3, contendo Montanide Gel-01 foi administrada em 22 caprinos (Gc3) e 12 ovinos (Gov3). Todos os animais eram negativos para Ma no ELISA indireto e receberam duas doses de 2mL cada, por via subcutânea, com intervalo de 21 dias. Cinco animais de cada espécie foram utilizados como controle. Setenta e cinco dias após o reforço, quatro animais de cada grupo vacinado e dois do grupo controle foram desafiados com 5mL de cultura de Ma contendo 10(7)ufc/mL, por via oral e pela imersão dos tetos das fêmeas em lactação. A resposta sorológica foi analisada nos dias da vacinação (zero e 21) e aos 51, 81, 111, 141 e 171 dias pós-vacinação. As coletas e análises dos animais desafiados foram realizadas no dia do desafio (D0) e sete, 14, 21, 28, 35, 42, 49 e 56 dias pós-desafio. As três vacinas induziram produção de anticorpos, não havendo diferença estatisticamente significativa entre caprinos e ovinos (P>0,05). Animais dos grupos Gc1, Gc2 e Gov2 produziram níveis de anticorpos mais elevados, com diferença estatisticamente significativa em relação aos demais grupos vacinados e ao grupo controle (P<0,05). Após o desafio, os animais do grupo controle apresentaram aumento de linfonodos regionais e conjuntivite, mastite e artrite. Em quatro animais vacinados, foi observada discreta conjuntivite e congestão dos vasos episclerais. Conclui-se que as vacinas 1 e 2 induziram níveis de anticorpos protetores em caprinos e ovinos suficientes para proteção clínica dos animais submetidos à infecção experimental, podendo ser indicadas para prevenção da agalaxia contagiosa.

Evaluación de un nuevo método turbidimétrico para la cuantificación de Beta-2 microglubulina en suero / Evaluation of a new turbidimetric analysis for the Beta-2 microglobulin cuantification in serum

Se ha evaluado el nuevo inmunoanálisis turbidimétrico para la determinación cuantitativa de la â-2 microglobulina desarrollado por Spinreact. El procedimiento se lleva a cabo de manera totalmente automática en el analizador de bioquímica clínica RA-500 con un intervalo analítico de 0,3 a 11 mg/l y límite de detección de 0,023 mg/l. Los coeficientes de variación obtenidos fueron inferiores a 5,2% para todos los niveles ensayados. El procedimiento evaluado es lineal dentro del intervalo de medida. La comparación con un Elisa (IMX, Abbot) mostró un coeficiente de correlación de 0,98, apreciándose la existencia de errores sistemáticos proporcionales constantes, probablemente debido a la diferente estandarización y, por tanto, diferentes valores de referencia de ambos métodos. El límite superior del intervalo de referencia (95 percentil) fue 43,6 mg/l. En conclusión, este nuevo método turbidimétrico puede considerarse un procedimiento adecuado para la medida fiable y precisa de la Beta-2 microglobulina, con un amplio intervalo analítico y una alta detectabilidad

The new turbidimetric analysis for the â-2microglobulin quantitative determination, developed by Spinreact, has been evaluated. The procedure is performed in a completely automatic way in the RA-500 clinical biochemistry analyser with an analytic interval ranging from 0,3 to 11 mg/l and 0,023 mg/l detection limit. All the variation coefficients obtained in this way were lower than 5,2% for all trial levels. The evaluated procedure is linear inside the measurement range. The comparison with Elisa (IMX, Abbot) showed an auto-correlation coefficient of 0,98, evidencing the existence of constant proportional systematic errors, due probably to different standards, and thus to different reference values in both methods. The reference interval upper limit (95 percentile) was 43,6 mg/l. Thus we can conclude that this new turbidimetric method is an adequate procedure to measure the Beta-2microglobulin in a reliable and accurate way, with a wide analytic range and high detection ability

Laboratory testing and rapid HIV assays: applications for HIV surveillance in hard-to-reach populations.

Most HIV surveillance has been performed through serologic surveys in relatively stable, accessible populations. Similar surveillance, with or without counseling and testing, in populations that are hard-to-reach, presents logistical challenges, including the selection of laboratory testing strategy and algorithm. The advent of rapid serologic assays for HIV now allows for on-site testing, including confirmatory testing, and rapid provision of test results and counseling. The possibility of only a single contact makes repeat sampling, which current diagnostic testing recommendations include, difficult. To address the logistical complexities in surveillance in hard-to-reach populations and the increased availability of rapid tests, we propose adapting the testing strategies for HIV of the World Health Organization/the joint United Nations Programme on HIV/AIDS in order to facilitate this surveillance, including, where carried out, the provision of test results back to individuals. The choice of enzyme-linked immunosorbent assay (ELISA) versus rapid testing for these settings is discussed, as is the choice of specimen--blood, oral fluid, or urine. Three appendices summarize: (1) test algorithms for the various testing strategies; (2) advantages and disadvantages of ELISA and of rapid test formats, and (3) the characteristics and status of currently available rapid HIV tests. We also discuss the potential application of the recently developed 'detuned' methodology for estimating HIV incidence in hard-to-reach populations.

Pesquisa de anti-HBc em doadores de sangue em Säo Paulo: deverá esse teste ser adotado pelo Brasil? / Anti-BHc research in blood donors in Säo Paulo: should this test be adopted in Brazil?

Objetivo do estudo: determinar a incidência de anticorpos contra o AgHBc (anti-HBc) no soro de doadores de sangue como método indireto de prevençäo de hepatite näo A-näo B pós-transfusional (HNANB-PT). Tipo de estudo: prospectivo, abrangendo toda a populaçäo de doadores de 1 de setembro a 31 de dezembro de 1989 (n = 2.773 doadores). Local: Hospital Sírio Libanês e 9 de Julho (Säo Paulo). Pacientes: total de 2.773 doadores, sendo 84% do sexo masculino e 16% do sexo feminino. Intervençöes: os testes foram executados por método ELISA competitivo. Medidas e resultados: no total geral, 10,2% dos doadores apresentavam anti-HBc repetidamente reativo, com maior incidência no sexo masculino (10,9% x 6,8% p < 0,05 ao X**2). Apenas 4,5% foram considerados borderline e 94,5% tiveram relaçäo absorçäo/cut-off < 0,9. Conclusöes: apesar da ausência de estudos prospectivos de HNANB-PT no país com correlaçäo de testes indiretos (anti-HBc), a alta incidência do anti-HBc em doadores permite a conclusäo de sua alta prevalência no Brasil. Embora os custos relacionados à doaçäo desse teste sejam elevados, sua indicaçäo em vários países, assim como a corrrelaçäo com testes mais específicos de primeira geraçäo (anti-HVC), permite a utilizaçäo do anti-HBc em centros hemoterápicos mais desenvolvidos no país

Resultados de ELISA en la prevalencia de lepra después de monoterapia

Se exponen y analizan los resultados de ELISA en pacientes (89,6 por ciento) de la prevalencia de lepra de 1988, en la ciudad de Camagüey, Cuba, despue´s de nomoterapia. Para realizar ELISA se usó el antígeno específico del M. leprae, el glicolípido fenólico-I. De acuerdo con el tiempo de tratamiento recibido, los resultados se correlacionaron con la clasificación sanitaria y las formas clínicas de la lepra según la clasificación de Madrid. el 77'2 por ciento de los casos multibacilares presentaron seronegatividad en ELISA, y entre ellos, el grupo de pacientes an 10 y más años de tratamiento tuvieron el porcentaje más elevado (46'3 por ciento). La seroposotividad de los casos paucibacilares (15'06 por ciento) se observó fundamentalmente en los primeros 5 años de tratamiento. Los pacientes con lepra lepromatosa tratados 10 y más años resultaron seronegativos en el 54'8 por ciento, pero la positividad persistió en el 12'2 por ciento de estos casos. Los pacientes con lepra dimorfa, tuberculoide e indeterminada bajos porcentajes de positividad (12'1; 13'4 y 14'3 respectivamente) principalmete durante los primeros 5 años de terapia.