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Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a food and waterborne pathogen with severe public health implications. We report the first-time isolation of this pathogen in the Central Highlands of Peru through standardized culture procedures and polymerase chain reaction (PCR). Escherichia coli strains were cultured from rectal-anal swabs from dairy calves and beef from food markets. The latex agglutination test was used to detect O157 and H7 antigens, and multiplex real-time PCR was carried out to detect virulence-related genes. The STEC O157:H7 strains were isolated from 3.5% (1/28) of beef samples and from 6.0% (3/50) of dairy calves that also carried both eaeA and stx1 genes. Therefore, this pathogen is a potential cause of food/waterborne disease in the region, and its surveillance in both livestock and their products should be improved to characterize the impact of its zoonotic transmission. From 2010 to 2020, E. coli was suspected in 10 outbreaks reported to the Peruvian Ministry of Health. Isolates from future outbreaks should be characterized to assess the burden posed by STEC O157:H7 in Peru.

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BACKGROUND: Cryptococcosis is a devastating opportunistic infection in immunocompromised individuals, primarily in people living with HIV/AIDS. This study evaluated a protocol for the early diagnosis of meningitis due to C. neoformans, utilizing established molecular techniques from serum and CSF samples. METHODS: The 18S and 5.8S (rDNA-ITS) sequence-specific nested PCR assays were compared with direct India ink staining and the latex agglutination test for detection of C. neoformans in serum and cerebrospinal fluid (CSF) from 49 Brazilian suspected meningitis patients. Results were validated with samples obtained from 10 patients negative for cryptococcosis and HIV, and by analysis of standard C. neoformans strains. PRINCIPAL FINDINGS: The 5.8S DNA-ITS PCR was more sensitive (89-100%) and specific (100%) than the 18S rDNA PCR and conventional tests (India ink staining and latex agglutination) for identification of C. neoformans. While the 18S PCR exhibited a sensitivity (72%) similar to that of the latex agglutination assay in serum samples, it was superior to the latex agglutination assay when testing CSF, with a sensitivity of 84%. However, the latex agglutination was superior to the 18SrDNA PCR in specificity in CSF (92%). The 5.8S DNA-ITS PCR yielded the highest levels of accuracy (96-100%) of any test for detection (serological and mycological) of C. neoformans in both serum and CSF. CONCLUSION: Use of the nested 5.8S PCR was superior to other techniques for the diagnosis of cryptococcosis. The possibility of using serum, a non-invasively collected material, in a targeted 5.8S PCR analysis to identify Cryptococcus spp. is recommended, especially in immunosuppressed patients. Our results indicate that nested 5.8S PCR can increase the diagnostic capability of cryptococcosis, and we suggest its use to monitor patients in the future.

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The chemical coupling of a protoplasmatic antigen from Mycobacterium avium subsp. paratubeculosis onto core-shell carboxylated particles was investigated with the aim of producing latex-protein complexes to be used in immunoagglutination assays capable of detecting bovine paratuberculosis disease. For this purpose, sensitizations were carried out using both colored and not colored carboxylated latexes as well as the protoplasmatic antigen at pH close to its isoelectric point to favor the antigenic protein to approach the particle surface. In all cases, higher fractions of proteins were chemically-bound to carboxyl groups on the surface of the particles. The assessment of the performance of the visual immunoagglutination assays consisted of evaluating 111 sera from healthy and infected bovines with Mycobacterium avium subsp. paratuberculosis. Complexes obtained from the colored latex allowed an acceptable visual discrimination between the studied positive and negative sera. Most of the positive samples showed strong to very strong agglutination and only a few samples reacted weakly, i.e. a sensitivity of 70%. The specificity of the assay, on the other hand, was 86%. Therefore, this rapid detection technique allows an easy and inexpensive identification of animals possibly infected with paratuberculosis "in situ" in the herds.

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O presente estudo foi realizado para determinar a prevalência geral de toxoplasmose em pavões de plumagem diferente e seu efeito nas enzimas de teste da função hepática dos hospedeiros. Um total de cem pavões de plumas diferenciais, como ombro preto (n = 52), azul (n = 28), branco (n = 10) e arlequim (n = 10) foram estudados no zoológico de Bahawalpur, no Paquistão, usando o Latex Agglutination Test (LAT) e ensaio imunossorvente ligado a enzima (ELISA). A prevalência geral por LAT e ELISA foi de 37% e 30%, respectivamente. Por LAT, observou-se uma prevalência não significativamente maior (P≥0,05) em gênero (37,77%) nos machos do que nas fêmeas (36,36%), enquanto os adultos apresentaram uma prevalência maior (37,97%) em relação aos jovens (33,33%). De acordo com o ELISA, uma prevalência significativamente (P <0,05) maior (35,55%) foi observada nos machos do que nas fêmeas (25,45%) e significativamente (P <0,05) maior prevalência (31,64%) foi registrada nos adultos do que nos jovens (23,80%). A análise do perfil bioquímico sérico mostrou que o nível de bilirrubina não teve elevação significativa nos hospedeiros infectados, em comparação aos não infectados, enquanto a concentração de albumina, alanina aminotransferase (ALT), aspartato aminotransferase (AST), fosfatase alcalina (ALP) foi significativamente (P <0,05) diferente nos hospedeiros infectados. Conclui-se que a toxoplasmose afeta as enzimas do teste da função hepática. Essa é uma pesquisa preliminar e requer mais pesquisas em todo o país, com populações e amostras maiores.(AU)

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Abstract Cryptococcosis is a fungal disease affecting more than one million people per yearworldwide. Its main etiological agents are Cryptococcus neoformans species complex and Cryp-tococcus gattii species complex. Cryptococcal meningitis (CM) is considered an AIDS-definingcondition. Rapid diagnosis by cryptococcal antigen assays, either the latex agglutination test(LA) or the lateral flow assay, is key to decreasing mortality due to cryptococcal disease. Theaim of the study was to develop a latex agglutination reagent (LA-ANLIS) for the rapid and reliable diagnosis of cryptococcosis in Argentina. This reagent will be produced in order to supplythe NMLN (National Mycology Laboratory Network). The evaluation of LA-ANLIS performanceand its comparison with the Cryptococcus Antigen Latex Agglutination Test System (LA-IMMY)(Immuno-Mycologics, Inc., USA) were conducted in 94 samples of cerebrospinal fluid. LA-ANLISand LA-IMMY compared exhibited 100% positive agreement and 97% negative agreement. LA-ANLIS showed 94% sensitivity and 97% specificity with the positive and negative predictivevalues of 94% and 97%, respectively. The LA-ANLIS is a reliable, reproducible and cost-effectivereagent, especially useful in countries where the commercial kit is not generally available andmust be obtained at a high cost. National production of reagents is the best choice for a reliableaccess to the rapid diagnosis of CM in Argentina.

Resumen La criptococosis es una enfermedad fúngica que afecta a más de un millón de personas por año en todo el mundo. Los principales agentes etiológicos pertenecen a los complejos de especies Cryptococcus neoformans y Cryptococcus gattii. La criptococosis meníngea (CM) se considera una enfermedad marcadora de sida. El diagnóstico rápido de esta enfermedad a través de la detección del antígeno de Cryptococcus, ya sea por aglutinación en partículas de látex o por inmunocromatografía, es clave para disminuir la mortalidad. El objetivo del presente estudio fue desarrollar un reactivo de aglutinación en partículas de látex para el diagnóstico rápido y certero de la CM en Argentina. Este reactivo (denominado en adelante LA-ANLIS) será producido para abastecer a la Red Nacional de Laboratorios de Micología. Se evaluó el desempeno del reactivo LA-ANLIS, y se realizó una comparación con el reactivo comercial Immuno-Mycologics, Inc. (en adelante, LA-IMMY) utilizando 94 muestras de líquido cefalorraquídeo. Hubo un 100% de acuerdo positivo y un 97% de acuerdo negativo entre los resultados obtenidos con los reactivos LA-ANLIS y LA-IMMY. El reactivo LA-ANLIS mostró una sensibilidad del 94% y una especificidad del 97%; los valores predictivos positivo y negativo fueron del 94 y del 97%, respectivamente. Se concluye que el LA-ANLIS es un reactivo confiable y rentable, que arroja resultados reproducibles, por lo que es especialmente útil en países donde los reactivos comerciales generalmente no están disponibles o sus costos son elevados. La producción nacional de reactivos es la mejor opción para asegurar el acceso de todos los hospitales al diagnóstico rápido de la CM en Argentina.

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The latex agglutination test using single-chain antibody fragments (scFvStx1 and scFvStx2) coupled to latex particles, was compared with the gold standard Vero cell assay for Shiga toxin (Stx) detection, aiming to estimate the diagnosis potential of these scFv fragments in a rapid and straightforward test. The latex complexes identified the presence of the toxins up to a 1:8 dilution in the majority of the evaluated strains. Moreover, the Stx concentration was indirectly determined in Stx-producing Escherichia coli (STEC) strains, allowing detection limit inference. A Stx dilution curve was constructed, and the data was analyzed in a non-linear model by second-order polynomial regression for prediction (p-value of 0.001 and a R2 above 0.98 were considered for correlations). The detection limit was 30 ng/mL for Stx1 and 10 ng/mL for Stx2. The scFvStx1 and scFvStx2 coupled to latex nanoparticles provide a toxin assay with a competitive Stx detection limit, which has a low cost and short execution time. The diagnostic method proposed here, using, for the first time, recombinant antibody fragments, raises the possibility of developing a more affordable test to be used in the routine detection and surveillance of STEC infections.

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BACKGROUND: Inflammatory/immunological serum markers are useful for the early detection of organ dysfunction, helping the diagnosis of sepsis. Although the detection of blood biomarkers is a standard practice, the use of noninvasive samples (eg saliva) would be beneficial. AIM: To investigate the saliva of hospitalized patients with and without sepsis and identify the levels of inflammatory markers such as C-reactive protein (CRP), procalcitonin (PCT), interleukin 6 (IL-6) and nitric oxide (NO). METHODS: Saliva samples were collected from 26 patients in intensive care unit with diagnosis of sepsis and from 26 without sepsis (control). The levels of CRP were determined by using latex agglutination test, whereas those of procalcitonin and IL-6 by ELISA and NO by the Griess reaction. RESULTS: Of 26 patients with sepsis, 14 were males (54%) with a mean age of 63.81 ± 3.48 years. The control group had the same distribution for gender, with mean age 65.04 ± 4.07 years. Sepsis group showed higher salivary concentrations of CRP, PCT, IL-6 and NO, with only levels of IL-6 being statistically different (P = .0001). CONCLUSIONS: Patients with sepsis had significantly higher levels of IL-6 in their saliva, suggesting that this biological sample could be useful in the diagnosis of this condition.

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Cryptococcosis is a fungal disease affecting more than one million people per year worldwide. Its main etiological agents are Cryptococcus neoformans species complex and Cryptococcus gattii species complex. Cryptococcal meningitis (CM) is considered an AIDS-defining condition. Rapid diagnosis by cryptococcal antigen assays, either the latex agglutination test (LA) or the lateral flow assay, is key to decreasing mortality due to cryptococcal disease. The aim of the study was to develop a latex agglutination reagent (LA-ANLIS) for the rapid and reliable diagnosis of cryptococcosis in Argentina. This reagent will be produced in order to supply the NMLN (National Mycology Laboratory Network). The evaluation of LA-ANLIS performance and its comparison with the Cryptococcus Antigen Latex Agglutination Test System (LA-IMMY) (Immuno-Mycologics, Inc., USA) were conducted in 94 samples of cerebrospinal fluid. LA-ANLIS and LA-IMMY compared exhibited 100% positive agreement and 97% negative agreement. LA-ANLIS showed 94% sensitivity and 97% specificity with the positive and negative predictive values of 94% and 97%, respectively. The LA-ANLIS is a reliable, reproducible and cost-effective reagent, especially useful in countries where the commercial kit is not generally available and must be obtained at a high cost. National production of reagents is the best choice for a reliable access to the rapid diagnosis of CM in Argentina.

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El síndrome de Guillain-Barré es una polirradiculoneuropatía aguda, en la cual está involucrado un componente autoinmunitario, posterior a un proceso infeccioso en pacientes no vacunados o vacunados. A partir de la aparición del virus del dengue y del Zika en el continente americano es de esperar que exista una mayor probabilidad de encontrar pacientes con este síndrome post-infeccioso. Por tanto, poder contar con un método diagnóstico rápido pudiera ser de utilidad en los centros de asistencia que reciben casos de urgencias. Se procede a modificar un método para cuantificar albuminuria por aglutinación con partículas de látex sensibilizados, para la detección de este analito en el líquido cefalorraquídeo de aquellos pacientes con sospecha de esta enfermedad. Se comprueba que el método puede ser utilizado como método de diagnóstico rápido del síndrome de Guillain-Barré(AU)

Guillain-Barré Syndrome is an acute poliradiculoneuropathy with an autoimmune component, subsequent to an infectious process in vaccinated or non-vaccinated patients. From the spreading of dengue and Zika infections in the American continent it is expected a greater probability of finding patients with this post-infectious syndrome. Therefore, a rapid diagnostic test could be useful in emergency assistance centers. A quantitative latex agglutination test to detect albuminuria was modified to be used in cerebrospinal fluid of patients with presumptive diagnosis of this disease. It has been proved that the developed test can be used for diagnostic rapid of Guillain-Barré syndrome(AU)

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Visceral leishmaniasis is a public health problem worldwide. The early diagnosis in dogs is crucial, since they are an epidemiologically relevant reservoir of the disease. The aim of a field study is to early identify the disease allowing rapid intervention to reduce its effects. We propose an immunoagglutination test as a visual in situ method for diagnosis of canine visceral leishmaniasis. Latex-protein complexes were sensitized by covalent coupling of a chimeric recombinant antigen of Leishmania spp. onto polystyrene latex with carboxyl functionality. The reaction time and the antigen concentration under which the immunoagglutination assay shows greater discrimination between the responses of a positive control serum and a negative control serum were determined. Then, the latex-protein complexes were evaluated as a visual diagnostic tool with a panel of 170 sera. The test may be read between 2 and 5 min and can be performed even using sera with elevated concentration of lipids, bilirubin or with variable percentage of hemolysis. The sensitivity, the specificity and the diagnostic accuracy were 78%; 100% and >80%, respectively. The visual immunoagglutination test is of potential application as a method for field studies because it shows results in less than 5 min, it is easy to implement and does not require sophisticated equipment.

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