Vitamin C and thiamine for the treatment of refractory septic shock in surgical critically ill patients: a retrospective before-and-after study.

OBJECTIVE: This study aimed to evaluate whether early vitamin C and thiamine administration was associated with a lower 28-day and in-hospital mortality in surgical critically ill patients with refractory septic shock. METHODS: We performed a retrospective before-and-after study on patients with refractory septic shock. According to local protocol, hydrocortisone is initiated in case of refractory septic shock. In January 2017, the protocol was changed and vitamin C and thiamine were included. Patients who were admitted in 2015-2016 and 2017-2018 were included in the control and treatment groups, respectively. The primary end point was 28-day and in-hospital mortality. Secondary end points were ICU mortality, ICU and hospital length of stay, duration of vasopressors and mechanical ventilation, use of renal replacement therapy (RRT), and the modification in serum procalcitonin and SOFA score during the first 72 h. RESULTS: A total of 120 patients were included (58 in the treatment group and 62 in the control group). Log-rank test in Kaplan-Meier curves showed lower 28-day and in-hospital mortality over time in the treatment group (p=0.021 and p=0.035, respectively) but it not reached statistical significance in ICU mortality over time (p=0.100). The need of RRT was less frequent in treatment group (17.2% vs. 37.1%, p=0.024). There were no differences in other secondary outcomes. CONCLUSIONS: Intravenous vitamin C and thiamine administration in surgical patients with refractory septic shock may be associated with a lower 28-day and in-hospital mortality. Further prospective studies are needed in refractory septic shock.

Factores asociados con la mortalidad por SARS-CoV-2 en la población mayor de 75 años de la Comunidad de Madrid / Factors associated with mortality due to SARS-CoV-2 in the population over 75 years of age in the Community of Madrid

Objetivo Diversos estudios han identificado factores asociados con el riesgo de muerte en pacientes infectados por SARS-CoV-2. Sin embargo, su tamaño muestral ha sido muchas veces limitado, y sus resultados parcialmente contradictorios. Este estudio ha evaluado los factores asociados con la mortalidad por COVID-19 en la población madrileña mayor de 75 años, en los pacientes infectados y en los hospitalizados hasta enero de 2021. Pacientes y métodos Estudio de cohortes de base poblacional con todos los residentes de la Comunidad de Madrid nacidos antes del 1 de enero de 1945 y vivos a 31 de diciembre de 2019. Se obtuvieron variables demográficas y clínicas de la historia clínica electrónica de atención primaria (AP-Madrid), de los ingresos hospitalarios a través del Conjunto Mínimo Básico de Datos (CMBD) y de la mortalidad a través del Índice Nacional de Defunciones (INDEF). Se recogieron los datos de infección, hospitalización y muerte por SARS-CoV-2 entre el 1 de marzo e 2020 y el 31 de enero de 2021. Resultados De los 587.603 sujetos incluidos en la cohorte, 41.603 (7,1%) desarrollaron una infección confirmada por SARS-CoV-2. De ellos, 22.362 (53,7% de los infectados) se hospitalizaron y 11.251 (27%) murieron. El sexo masculino y la edad fueron los factores más asociados con la mortalidad, si bien también contribuyeron numerosas comorbilidades. La asociación fue de mayor magnitud en los análisis poblacionales que en los análisis con pacientes infectados u hospitalizados. La mortalidad en los hospitalizados fue menor en la segunda ola (33,4%) que en la primera ola (41,2%) de la pandemia Conclusión La edad, el sexo y las numerosas comorbilidades se asocian con el riesgo de muerte por COVID-19. La mortalidad en los pacientes hospitalizados se redujo apreciablemente después de la primera ola de la pandemia (AU)

Objective Various studies have identified factors associated with risk of mortality in patients with SARS-CoV-2 infection. However, their sample size has often been limited and their results partially contradictory. This study evaluated factors associated with COVID-19 mortality in the population of Madrid over 75 years of age, in infected patients, and in hospitalized patients up to January 2021. Patients and Methods This population-based cohort study analyzed all residents of the Community of Madrid born before January 1, 1945 who were alive as of December 31, 2019. Demographic and clinical data were obtained from primary care electronic medical records (PC-Madrid), data on hospital admissions from the Conjunto Mínimo Básico de Datos (CMBD, Minimum Data Set), and data on mortality from the Índice Nacional de Defunciones (INDEF, National Death Index). Data on SARS-CoV-2 infection, hospitalization, and death were collected from March 1, 2020 to January 31, 2021. Results A total of 587,603 subjects were included in the cohort. Of them, 41,603 (7.1%) had confirmed SARS-CoV-2 infection, of which 22,362 (53.7% of the infected individuals) were hospitalized and 11,251 (27%) died. Male sex and age were the factors most closely associated with mortality, though many comorbidities also had an influence. The associations were stronger in the analysis of the total population than in the analysis of infected or hospitalized patients. Mortality among hospitalized patients was lower during the second wave (33.4%) than during the first wave (41.2%) of the pandemic. Conclusion Age, sex, and numerous comorbidities are associated with risk of death due to COVID-19. Mortality in hospitalized patients declined notably after the first wave of the pandemic (AU)

Factors associated with mortality due to SARS-CoV-2 in the population over 75 years of age in the Community of Madrid.

OBJECTIVE: Various studies have identified factors associated with risk of mortality in patients with SARS-CoV-2 infection. However, their sample size has often been limited and their results partially contradictory. This study evaluated factors associated with COVID-19 mortality in the population of Madrid over 75 years of age, in infected patients, and in hospitalized patients up to January 2021. PATIENTS AND METHODS: This population-based cohort study analyzed all residents of the Community of Madrid born before January 1, 1945 who were alive as of December 31, 2019. Demographic and clinical data were obtained from primary care electronic medical records (PC-Madrid), data on hospital admissions from the Conjunto Mínimo Básico de Datos (CMBD, Minimum Data Set), and data on mortality from the Índice Nacional de Defunciones (INDEF, National Death Index). Data on SARS-CoV-2 infection, hospitalization, and death were collected from March 1, 2020 to January 31, 2021. RESULTS: A total of 587,603 subjects were included in the cohort. Of them, 41,603 (7.1%) had confirmed SARS-CoV-2 infection, of which 22,362 (53.7% of the infected individuals) were hospitalized and 11,251 (27%) died. Male sex and age were the factors most closely associated with mortality, though many comorbidities also had an influence. The associations were stronger in the analysis of the total population than in the analysis of infected or hospitalized patients. Mortality among hospitalized patients was lower during the second wave (33.4%) than during the first wave (41.2%) of the pandemic. CONCLUSION: Age, sex, and numerous comorbidities are associated with risk of death due to COVID-19. Mortality in hospitalized patients declined notably after the first wave of the pandemic.

[Factors associated with mortality due to SARS-CoV-2 in the population over 75 years of age in the Community of Madrid]. / Factores asociados con la mortalidad por SARS-CoV-2 en la población mayor de 75 años de la Comunidad de Madrid.

Objective: Various studies have identified factors associated with risk of mortality in patients with SARS-CoV-2 infection. However, their sample size has often been limited and their results partially contradictory. This study evaluated factors associated with COVID-19 mortality in the population of Madrid over 75 years of age, in infected patients, and in hospitalized patients up to January 2021. Patients and methods: This population-based cohort study analyzed all residents of the Community of Madrid born before January 1, 1945 who were alive as of December 31, 2019. Demographic and clinical data were obtained from primary care electronic medical records (PC-Madrid), data on hospital admissions from the Conjunto Mínimo Básico de Datos (CMBD, Minimum Data Set), and data on mortality from the Índice Nacional de Defunciones (INDEF, National Death Index). Data on SARS-CoV-2 infection, hospitalization, and death were collected from March 1, 2020 to January 31, 2021. Results: A total of 587,603 subjects were included in the cohort. Of them, 41,603 (7.1%) had confirmed SARS-CoV-2 infection, of which 22,362 (53.7% of the infected individuals) were hospitalized and 11,251 (27%) died. Male sex and age were the factors most closely associated with mortality, though many comorbidities also had an influence. The associations were stronger in the analysis of the total population than in the analysis of infected or hospitalized patients. Mortality among hospitalized patients was lower during the second wave (33.4%) than during the first wave (41.2%) of the pandemic. Conclusion: Age, sex, and numerous comorbidities are associated with risk of death due to COVID-19. Mortality in hospitalized patients declined notably after the first wave of the pandemic.

Biochemical algorithm to identify individuals with ALPL variants among subjects with persistent hypophosphatasaemia.

BACKGROUND: Hypophosphatasia (HPP) is a rare and underdiagnosed condition characterized by deficient bone and teeth mineralization. The aim of this study was first, to evaluate the diagnostic utility of employing alkaline phosphatase (ALP) threshold levels to identify adults with variants in ALPL among individuals with persistently low ALP levels and second, to determine the value of also including its substrates (serum pyridoxal-5'-phosphate-PLP-and urinary phosphoetanolamine-PEA) for this purpose in order to create a biochemical algorithm that could facilitate the diagnostic work-up of HPP. RESULTS: The study population comprised 77 subjects with persistent hypophosphatasaemia. They were divided into two groups according to the presence (+GT) or absence (-GT) of pathogenic ALPL variants: 40 +GT and 37 -GT. Diagnostic utility measures were calculated for different ALP thresholds and Receiver Operating Characteristic (ROC) curves were employed to determine PLP and PEA optimal cut-off levels to predict the presence of variants. The optimal threshold for ALP was 25 IU/L; for PLP, 180 nmol/L and for PEA, 30 µmol/g creatinine. Biochemical predictive models were assessed using binary logistic regression analysis and bootstrapping machine learning technique and results were then validated. For ALP < 25 UI/L (model 1), the area under curve (AUC) and the 95% confidence intervals (CI) was 0.68 (95% CI 0.63-0.72) and it improved to 0.87 (95% CI 0.8-0.9), when PEA or PLP threshold levels were added (models 2 and 3), reaching 0.94 (0.91-0.97) when both substrates were included (model 4). The internal validation showed that the addition of serum PLP threshold levels to the model just including ALP improved significantly sensitivity (S) and negative predictive value (NPV) - 100%, respectively- with an accuracy (AC) of 93% in comparison to the inclusion of urinary PEA (S: 71%; NPV 75% and AC: 79%) and similar diagnostic utility measures as those observed in model 3 were detected when both substrates were added. CONCLUSIONS: In this study, we propose a biochemical predictive model based on the threshold levels of the main biochemical markers of HPP (ALP < 25 IU/L and PLP > 180 nmol/L) that when combined, seem to be very useful to identify individuals with ALPL variants.

Real-world experience of palbociclib and ribociclib: novel oral therapy in metastatic breast cancer.

Background Palbociclib and ribociclib are novel oral agents in hormone receptor-positive metastatic breast cancer. Neutropenia is a common adverse event associated with these treatments and its clinical management often requires regimen changes, such as cycle delays and dose adjustments. Objective To provide a real-world experience of the effectiveness and toxicities associated with these drugs and to evaluate the impact of regimen changes in disease progression. Setting This study was performed at Hospital Universitario La Paz, in Spain. Methods Observational, retrospective study which included hormone receptor-positive metastatic breast cancer patients who initiated treatment with palbociclib or ribociclib between March 1st, 2018 and March 1st, 2019. Main outcome measure The primary effectiveness variable was progression-free survival. Safety evaluation was performed to determine neutropenia-incidence and severity, as well as its clinical management, including dose adjustments and treatment interruptions. Correlations between these regimen changes and effectiveness were also evaluated. Results Sixty-one patients were included, 33 treated with palbociclib and 28 with ribociclib. Palbociclib was mainly used as second line of treatment in the metastatic setting (81.8%) and ribociclib as first line (67.9%). The median progression-free survival was 12.76 months (95% CI 7.5 to not estimable) in palbociclib and not reached in ribociclib. After 12 months, the progression-free survival rate was 51.5% (95% CI 34-69) in palbociclib and 78.6% (95% CI 63-94.1) in ribociclib. Neutropenia was the most common adverse event with an incidence rate of 87.9% in palbociclib and 82.1% in ribociclib. Cycle delays were needed in more than half of the patients treated with palbociclib and ribociclib (63.6% and 64.3%). Dose adjustments were seen in 42.4% and 53.6% of the patients receiving palbociclib and ribociclib, respectively. Regimen changes did not involve statistically significant differences in 12-month PFS rates in the cohort investigated. Conclusion Palbociclib and ribociclib outcomes are comparable to those reached in the phase III trials, PALOMA-3 and MONALEESA-2, respectively, and cannot be compared as they were used in different treatment settings. The toxicity profile is favourable, being neutropenia the most common adverse event, easily managed with regimen changes. Further studies are needed to confirm the observed tendency of no detrimental impact on effectiveness of these regimen changes.

Is it always necessary to perform an axillary lymph node dissection after neoadjuvant chemotherapy for breast cancer?

INTRODUCTION: Recent prospective studies support the feasibility of performing sentinel lymph node biopsy following neoadjuvant chemotherapy in initially fine-needle aspiration cytology or ultrasound-guided biopsy-proven node-positive breast cancer. The main aid is to identify preoperative features that help us predict a complete axillary response to neoadjuvant chemotherapy in these patients and thus select the candidates for sentinel lymph node biopsy post-neoadjuvant chemotherapy to avoid unnecessary axillary lymphadenectomy. MATERIALS AND METHODS: A retrospective observational study with a total of 150 patients, biopsy-proven node-positive breast cancer who underwent neoadjuvant chemotherapy followed by breast surgery and axillary lymphadenectomy were included and retrospectively analysed. A predictive model was generated by a multivariate logistic regression analysis for pathological complete response-dependent variable. RESULTS: The response of the primary lesion to neoadjuvant chemotherapy according to post-treatment magnetic resonance imaging, Her2/neu overexpression and a low estrogen receptor expression are associated with a higher rate of nodal pathologically complete response. The multivariant model generated a receiver operating characteristic curve with an area under the curve of 0.79 and a confidence interval of 0.72-0.87 at a 95% level of significance. CONCLUSIONS: This model could be a helpful tool for the surgeon to help in predicting which cases have a higher likelihood of achieving a pathologically complete response and therefore selecting those who may benefit from a post-neoadjuvant chemotherapy sentinel lymph node biopsy and avoid unnecessary axillary lymphadenectomy.

Asthma exacerbations in a tertiary hospital: clinical features, triggers, and risk factors for hospitalization

Background: The risk factors for asthma exacerbations are not fully understood. The aim of this study was to determine the epidemiological and clinical characteristics of patients who experience asthma exacerbations. We also assessed potential triggers of exacerbations and possible predictors of hospitalization. Methods: A retrospective, noninterventional cohort study was conducted in adult patients who attended the emergency department of a tertiary hospital with an asthma exacerbation during 2014. Results: The study population comprised 831 patients (888 events). Most episodes occurred in January and May. Respiratory infection was the trigger in 523 events. In 34.21% of cases, the eosinophil count was ≥260/mm3 (≥400/mm3 in 20.7%), which was significantly associated with allergic asthma (P<.0001). The risk factors for hospitalization were older age (OR, 1.58; 95%CI, 1.46-1.71), no previous diagnosis of asthma (OR, 1.40; 95%CI, 1.06-1.86), poorly controlled asthma (OR, 1.78; 95%CI, 1.10-2.88), respiratory infection (OR, 2.65; 95%CI, 1.95-3.62), and severe exacerbation with more treatment requirements. The rate of hospitalization was significantly lower in patients with ≥400 eosinophils/mm3 (P<.001). Conclusion: Older age, absence of a previous asthma diagnosis, uncontrolled disease, and concomitant chronic obstructive pulmonary disease are frequent among patients presenting at the emergency department with asthma exacerbations. Various features were associated with a higher risk of admission. Blood eosinophilia should be considered a marker of asthma, but not a predictor of hospitalization (AU)

Introducción: Los factores de riesgo de las exacerbaciones de asma no se conocen por completo. El objetivo de este estudio fue determinar las características epidemiológicas y clínicas de los pacientes con exacerbaciones de asma, los potenciales factores desencadenantes y los posibles predictores de hospitalización. Métodos: Se llevó a cabo un estudio de cohorte retrospectivo, no intervencionista, en pacientes adultos que acudieron al Servicio de Urgencias de un hospital terciario con una exacerbación de asma durante el año 2014. Resultados: Se incluyeron 831 pacientes (888 eventos). El mayor número de episodios ocurrió en Enero y Mayo. La infección respiratoria se consideró como desencadenante en 523 eventos. 34,21% tenían ≥260 eosinófilos/mm3 (20,7% ≥ 400 eosinófilos/mm3), estando lo cual asociado significativamente con el asma alérgica (p<0,0001). Los factores de riesgo para la hospitalización fueron: edad avanzada [OR: 1,58 (IC 95%: 1,46 a 1,71)]; ausencia de diagnóstico previo de asma [OR: 1,40 (IC 95%: 1,06-1,86)]; mal control del asma [OR: 1,78 (IC 95%: 1,10-2,88)]; infección respiratoria [OR: 2,65 (IC 95%: 1,95-3,62)]; y crisis graves con mayor necesidad de tratamiento. En los asmáticos con ≥ 400 eosinófilos/mm3, la tasa de hospitalización fue menor (p <0,001). Conclusión: La edad avanzada, la ausencia de un diagnóstico de asma previo, el mal control de la enfermedad o el padecer EPOC de forma concomitante son frecuentes entre los pacientes que acuden al Servicio de Urgencias con exacerbaciones de asma. Se detectaron algunas características asociadas con un mayor riesgo de ingreso. La eosinofilia periférica debe ser considerada como un marcador de asma, pero no como un predictor de la hospitalización (AU)

Asthma exacerbations in a tertiary hospital: clinical features, triggers, and risk factors for hospitalization.

BACKGROUND: Risk factors for asthma exacerbations are not fully understood. The aim of this study was to determine the epidemiological and clinical characteristics of patients with an asthma exacerbation, potential triggers, and possible predictors of hospitalization. METHODS: A retrospective, non-interventional cohort study was conducted in adult patients who attended the Emergency Department of a tertiary hospital with an asthma exacerbation during 2014. RESULTS: 831 patients (888 events) were included. The highest number of episodes occurred in January and May. Respiratory infection was considered the trigger in 523 events. 34.21% had ≥260 eosinophils/mm3 (20.7%≥400 eosinophils/mm3), significantly associated with allergic asthma (p<0.0001). Risk factors for hospitalization were: older age [OR:1.58 (95% CI 1.46-1.71)]; no previous diagnosis of asthma [OR:1.40(95% CI 1.06-1.86)]; poorly controlled asthma[OR:1.78 (95% CI 1.10-2.88)]; respiratory infection [OR:2.65 (95% CI 1.95-3.62)]; and severe crisis with more treatment requirements. Of those asthmatics with ≥400 eosinophils/mm3, the rate of hospitalization was lower (p<0.001). CONCLUSION: Older age, absence of a previous asthma diagnosis, uncontrolled disease or concomitant COPD are frequent among patients presenting to the ED with asthma exacerbations. There were some features associated with higher risk of admission. Blood eosinophilia should be considered as a marker of asthma, but not as a predictor of hospitalization.

Does the profile of sensitization to grass pollen allergens have clinical relevance?

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Prevalencia de anemia en varias comunidades de la etnia Nivaclé del Chaco paraguayo / Prevalence of anemia in several communities of the Nivaclé ethnic group of the Paraguayan Chaco

La anemia es la concentración de la hemoglobina por debajo de los valores límites establecidos. Las comunidades indígenas de la etnia Nivaclé que habitan el Chaco paraguayo viven bajo condiciones de extrema pobreza, careciendo de asistencia sanitaria y de programas de control de enfermedades. Este estudio descriptivo de corte transversal realizado de junio de 2001 a marzo de 2002, tuvo como objetivo establecer la prevalencia y distribución de anemia en hombres y mujeres de 15 a 65 años, de la etnia Nivaclé que habitan en el Chaco paraguayo. Se incluyó a todos los indígenas voluntarios sanos presentes en el momento del estudio que aceptaron participar, previo consentimiento informado. La concentración de hemoglobina se determinó en 379 indígenas Nivaclé. La OMS considera que existe anemia en los adultos (a partir de 15 años), cuando la concentración de hemoglobina es inferior a 130 g/L para el sexo masculino y menor a 120 g/l para el femenino. La prevalencia de anemia en mujeres n= 217 fue de 49,8 % (con media hemoglobina de 117,67 ± 12,16 g/L); y en los hombres n= 162 resultó de 33,3 % (promedio de hemoglobina de 132,62 ± 11,65 g/L). La elevada prevalencia de anemia observada, especialmente en mujeres, se debería a una pobre nutrición, lo que conlleva a una mala salud que justifica la incorporación de estrategias de atención primaria de salud que se adapten a la cultura y a las condiciones de estas comunidades.

Hepatitis virales en diferentes grupos étnicos del Paraguay / Viral hepatitis in different ethnic groups of Paraguay

La hepatitis viral es uno de los principales problemas de salud pública en las Américas. El virus de la hepatitis B (VHB) y el virus de la hepatitis C (VHC) se transmiten principalmente por vía sexual, intravenosa y perinatal. Estudios previos, en grupos indígenas Ayoreo­paraguayos, muestran una prevalencia de 17,4% para el antígeno de superficie de la Hepatitis B (HBsAg) y de 14,9% para VHC. El objetivo del presente trabajo fue determinar la prevalencia de la infección para el VHB y VHC en dos grupos étnicos bien diferenciados que habitan la región occidental: Mennonita y una población indígena Enxet ubicados en el Chaco central. Estas dos poblaciones son de poca movilidad territorial y bajo contacto con la sociedad nacional. Con un consentimiento previo se analizó un total de 74 sueros pertenecientes a los grupos étnicos Mennonita (52) y Enxet (22) en un rango de edad entre 16 y 65 años. La detección del antígeno de superficie de la Hepatitis B (HbsAg) y de los anticuerpos anti­VHC se realizó por el método ELISA (Human­Alemania). En ninguna de las dos poblaciones estudiadas se detectó la presencia del HBsAg y de anticuerpos anti­VHC. El aislamiento geográfico y normas socioculturales explicarían la ausencia de estas hepatitis virales en contraposición a los patrones culturales del grupo étnico de los Ayoreo del noreste del Chaco Paraguayo. En el diseño de programas de prevención de la transmisión de enfermedades de transmisión sexual se deben tener en cuenta estas pautas culturales.

Viral hepatitis is a main public health problem in the Americas. Hepatitis B (HBV) and hepatitis C (HCV) viruses are transmitted by sexual, intravenous and perinatal via. Previous studies in Ayoreo aborigine population of the eastern Paraguayan Chaco showed prevalences of 17.4% and 14.9% of HBV and HCV respectively. The objective of the present study was to determine the prevalence of HBV and HCV infection in two well differentiated ethnic groups from the western region of Paraguay: a Mennonite and an aborigine Enxet population located in the central Chaco. These two populations are from rural areas with low contact with urban society. After obtaining the previous informed consent, a total of 74 sera from Mennonite (52) and Enxet (22) individuals were analyzed with in an age range of 16 to 65 years. Detection of surface antigen of hepatitis B virus (HBsAg) and total antibodies anti­HCV was carried out using a commercial ELISA kit (Human­Germany). In none of the two populations, Mennonite and Enxet, the presence of HBsAg and anti­HCV antibodies was detected. Geographical isolation and sociocultural rules may explain the absence of the studied viral hepatitis in these populations in contrast to Ayoreo aborigine population that has different cultural patterns. When prevention programs of sexually transmitted infections are designed, these cultural patterns should be considered.

Implementación y evaluación de un sistema localmente sustentable de diagnostico prenatal que permite detectar casos de transmisión congénita de la enfermedad de Chagas en zonas endémicas del Paraguay / Implementation and evaluation of a locally sustainable system of prenatal diagnosis to detect cases of congenital Chagas disease in endemic areas of Paraguay

A locally sustainable system of prenatal screening of Trypanosoma cruzi infection has been implemented in rural health care centers of endemic areas in Paraguay A total of 61.091 women from Paraguari and Cordillera Departments were serologically evaluated, where 7.802 (12,7%) resulted to be anti-T. cruzi IgG positive. A total of 1,865 infants born to seropositive mothers were examined by parasitological techniques, such as direct microscopic observation and polymerase chain reaction, and serologically by ELISA, ELISA-SAPA and IFI. 104 infected babies were detected and treated with benznidazole. The recovery of babies born to seropositive mothers performing a single examination at the age of 6 months was significantly higher, as compared with the recommended method involving two examinations, both at birth and after 6 months of age. Although at 6 months of age in 7% of the infants maternal IgG was still detected. PCR was the most sensitive technique for early detection of T. cruzi infection in babies, but we do not recommend it use for diagnosis in high endemic areas, considering that for the screening of 815 babies, 2000 reactions were needed. We propose a strategy to detect congenital transmission of Chagas disease, based on a large-scale study, where the shortcomings of the different serological and parasitological techniques are discussed.

Ferrochelatase is present in Brucella abortus and is critical for its intracellular survival and virulence.

Brucella spp. are pathogenic bacteria that cause brucellosis, an animal disease which can also affect humans. Although understanding the pathogenesis is important for the health of animals and humans, little is known about virulence factors associated with it. In order for chronic disease to be established, Brucella spp. have developed the ability to survive inside phagocytes by evading cell defenses. It hides inside vacuoles, where it then replicates, indicating that it has an active metabolism. The purpose of this work was to obtain better insight into the intracellular metabolism of Brucella abortus. During a B. abortus genomic sequencing project, a clone coding a putative gene homologous to hemH was identified and sequenced. The amino acid sequence revealed high homology to members of the ferrochelatase family. A knockout mutant displayed auxotrophy for hemin, defective intracellular survival inside J774 and HeLa cells, and lack of virulence in BALB/c mice. This phenotype was overcome by complementing the mutant strain with a plasmid harboring wild-type hemH. These data demonstrate that B. abortus synthesizes its own heme and also has the ability to use an external source of heme; however, inside cells, there is not enough available heme to support its intracellular metabolism. It is concluded that ferrochelatase is essential for the multiplication and intracellular survival of B. abortus and thus for the establishment of chronic disease as well.

Genetic diversity, distribution, and serological features of hantavirus infection in five countries in South America.

Since 1995 when the first case of hantavirus pulmonary syndrome (HPS) was reported in Patagonia, there have been more than 400 cases of HPS reported in five countries in South America. The first case of HPS was associated with Andes (AND) virus. In this study, we report on the genetic diversity, geographical distribution, and serological features of hantavirus infection in six countries in South America based on 87 HPS cases from Argentina, Bolivia, Chile, Paraguay, and Uruguay. An early immunoglobulin M (IgM), IgA, and IgG humoral response was observed in almost all HPS cases. The IgM response appears to peak 1 or 2 days after the onset of symptoms. Peak IgG antibody titers occur mostly after the first week. Low IgG titers or the absence of IgG was associated with higher mortality rates. The IgA response peaks around day 15 and then rapidly decreases. The results of phylogenetic analysis based on partial M-fragment G1- and G2-encoding sequences showed that HPS cases from the five countries were infected with viruses related to AND or Laguna Negra (LN) virus. Within AND virus-infected persons, at least five major genetic lineages were found; one lineage was detected in Uruguayan and Argentinean cases from both sides of the Rio de la Plata river. Two Paraguayan patients were infected with a virus different from LN virus. According to the results of phylogenetic analyses, this virus probably belongs to a distinct lineage related more closely to the AND virus than to the LN virus, suggesting that there is probably an Oligoryzomys-borne viral variant circulating in Paraguay. These studies may contribute to a better understanding of hantavirus human infection in South America.

Role of the Escherichia coli SurA protein in stationary-phase survival.

SurA is a periplasmic peptidyl-prolyl isomerase required for the efficient folding of extracytoplasmic proteins. Although the surA gene had been identified in a screen for mutants that failed to survive in stationary phase, the role played by SurA in stationary-phase survival remained unknown. The results presented here demonstrate that the survival defect of surA mutants is due to their inability to grow at elevated pH in the absence of sigmaS. When cultures of Escherichia coli were grown in peptide-rich Luria-Bertani medium, the majority of the cells lost viability during the first two to three days of incubation in stationary phase as the pH rose to pH 9. At this time the surviving cells resumed growth. In cultures of surA rpoS double mutants the survivors lysed as they attempted to resume growth at the elevated pH. Cells lacking penicillin binding protein 3 and sigmaS had a survival defect similar to that of surA rpoS double mutants, suggesting that SurA foldase activity is important for the proper assembly of the cell wall-synthesizing apparatus.

Treatment of congenital Chagas' disease diagnosed and followed up by the polymerase chain reaction.

In 1991 and 1992, a prenatal screening of Trypanosoma cruzi infection was carried out using ELISA and indirect immunofluorescence techniques. A total of 840 blood samples from pregnant women, obtained at the Maternity Ward of the Hospital de Clínicas, National University of Asunción (Asunción, Paraguay), and 1,022 samples from the Regional Hospital of the San Pedro Department of Paraguay were examined. It was observed that 7.7% and 10.5%, respectively, of the pregnant women were serologically positive for infection with T. cruzi. When blood samples obtained from newborns on the day of birth or, at the most, on the first few days afterwards were examined by direct microscopic observation, an incidence of congenital transmission of 3% was found. These results are consistent with those of neighboring countries. When a serologic follow-up was conducted on the newborns until six months of age, the incidence of congenital transmission reached 10%. The same incidence rate was obtained when the samples collected during the first days after birth were examined by the polymerase chain reaction (PCR). Fifty-eight infants born to seropositive mothers were followed-up, two of which were positive by direct microscopic observation at birth, and four who were PCR-positive, but microscopy-negative at birth. None of the infants were positive for IgM at birth. The infected babies were treated with benznidazole and were followed-up by serology and PCR for four years. We conclude that the PCR has a clear advantage over conventional techniques for the early detection of congenital transmission of T. cruzi infection, and for monitoring infants undergoing chemotherapy.

Detección de ADN de Trypanosoma cruzi en heces secas de triatoma infestans: PCR vs Xenodiagnostico en un apoblación de niños infectados / Annual reports 1995 / Detection of Trypanosoma cruzi DNA in dried feces of triatoma infestans: Comparison of PCR with Xenodiagnosis in chronic Chagasic patients

En la enfermedad de Chagas, la detección del agente T. cruzi en sangre circulante se considera fundamental para el diagnòstico en infecciones recientes (etapa aguda) como ser: transmisión congénita, accidentes de laboratorio, transfución sanguínea y en aquellos casos de sospecha de picadura del insecto vector. En la etapa crónica de la enfermedad (cuyo inicio no es fácil de definir), el diagnóstico se basa en técnicas serológicas y la detección de parasitos en sangre puede considerarse como un criterio válido para iniciar el tratamiento antichagásico en individuos jóvenes. La sensibilidad de las técnicas convencionales parasitológicas en la etapa crónica de la enfermermedad de Chagas es muy baja considerandose como mejor método al xenodiagnóstico con una sensibilidad del 30-50 por ciento . Actualmente la técnica de amplificación de ADN, reacción en cadena de la polimerasa (PCR) aplicada a muestras de sangre de individuos infectados con T.cruzi en forma crónica, ha demostrado una sensibilidad de 80 por ciento. No hemos propuesto verificar si el PCR combinado con una amplificación biológica como el Xenodiagnóstico, aumenta la sensibilidad de la detección de paràsitos circulantes en sangre. Con este objetivo se sometió a xenodiagnóstico a 22 niños seropositivos para T. cruzi y 3 seronegaticos. Los T. infestans empleados en el xenodiagnóstico, se colocaron en frascos individuales y se analizaron las heces depositadas en papeles de filtro, correspondiente a los primeros 8 días. Se analizaron por PCR, i) las muestras de sangre de estos niños y, ii) las heces secas de T. infestans depositadas en papel de filtro. De los 22 niños seropisitivos, 3 (13.6 por ciento) tuvieron parasitemia directa positiva, y 17(&& por ciento) fueron niños positivos por la técnica PCR en sangre. Se obtuvieron resultados de xenodiagnostico en solo 19 niños seropositivos cuyas vinchucas sobrevivieron los 45 días necesarios para el xenodiagnóstico; encontrandose que 11 de las 19 muestras (58 por ciento) fueron positivas. Sin embargo, al aplicar el PCR a las heces secas se detecto ADN de T. cruzi en 16 de las 19 muestras aumentando el numero de muestras positivas a un 84 por ciento.

Long-lasting antibodies detected by a trans-sialidase inhibition assay of sera from parasite-free, serologically cured chagasic patients.

A test based on the inhibition by antibodies of the trans-sialidase was used to analyze infection by Trypanosoma cruzi, the agent of Chagas' disease. Sera collected during the longitudinal follow-up of benznidazole-treated acutely and congenitally infected patients became negative for T. cruzi as determined by tests presently used to assess cure; however, the sera remained positive for T. cruzi by the trans-sialidase inhibition assay (TIA) up to 14 years after treatment. Therefore, TIA is a highly sensitive marker for previous T. cruzi infection.