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Background: Human metapneumovirus (hMPV) is one of the leading respiratory viruses. This prospective observational study aimed to describe the clinical features and the outcomes of hMPV-associated lower respiratory tract infections in adult inpatients. Methods: Consecutive adult patients admitted to one of the 31 participating centers with an acute lower respiratory tract infection and a respiratory multiplex PCR positive for hMPV were included. A primary composite end point of complicated course (hospital death and/or the need for invasive mechanical ventilation) was used. Results: Between March 2018 and May 2019, 208 patients were included. The median age was 74 [62–84] years. Ninety-seven (47 %) patients were men, 187 (90 %) had at least one coexisting illness, and 67 (31 %) were immunocompromised. Median time between first symptoms and hospital admission was 3 [2–7] days. The two most frequent symptoms were dyspnea (86 %) and cough (85 %). The three most frequent clinical diagnoses were pneumonia (42 %), acute bronchitis (20 %) and acute exacerbation of chronic obstructive pulmonary disease (16 %). Among the 52 (25 %) patients who had a lung CT-scan, the most frequent abnormality was ground glass opacity (41 %). While over four-fifths of patients (81 %) received empirical antibiotic therapy, a bacterial coinfection was diagnosed in 61 (29 %) patients. Mixed flora (16 %) and enterobacteria (5 %) were the predominant documentations. The composite criterion of complicated course was assessable in 202 (97 %) patients, and present in 37 (18 %) of them. In the subpopulation of pneumonia patients (42 %), we observed a more complicated course in those with a bacterial coinfection (8/24, 33 %) as compared to those without (5/60, 8 %) (p = 0.02). Sixty (29 %) patients were admitted to the intensive care unit. Among them, 23 (38 %) patients required invasive mechanical ventilation. In multivariable analysis, tachycardia and alteration of consciousness were identified as risk factors for complicated course. Conclusion: hMPV-associated lower respiratory tract infections in adult inpatients mostly involved elderly people with pre-existing conditions. Bacterial coinfection was present in nearly 30 % of the patients. The need for mechanical ventilation and/or the hospital death were observed in almost 20 % of the patients.

Abstract Background In the last decade, Ibrutinib has become the standard of care in the treatment of several lymphoproliferative diseases such as chronic lymphocytic leukemia (CLL) and several non-Hodgkin lymphoma. Beyond Bruton tyrosine kinase inhibition, Ibrutinib shows broad immunomodulatory effects that may promote the occurrence of infectious complications, including opportunistic infections. The infectious burden has been shown to vary by disease status, neutropenia, and prior therapy but data focusing on severe infections requiring intensive care unit (ICU) admission remain scarce. We sought to investigate features and outcomes of severe infections in a multicenter cohort of 69 patients receiving ibrutinib admitted to 10 French intensive care units (ICU) from 1 January 2015 to 31 December 2020. Results Median time from ibrutinib initiation was 6.6 [3–18] months. Invasive fungal infections (IFI) accounted for 19% (n = 13/69) of severe infections, including 9 (69%; n = 9/13) invasive aspergillosis, 3 (23%; n = 3/13) Pneumocystis pneumonia, and 1 (8%; n = 1/13) cryptococcosis. Most common organ injury was acute respiratory failure (ARF) (71%; n = 49/69) and 41% (n = 28/69) of patients required mechanical ventilation. Twenty (29%; n = 20/69) patients died in the ICU while day-90 mortality reached 55% (n = 35/64). In comparison with survivors, decedents displayed more severe organ dysfunctions (SOFA 7 [5–11] vs. 4 [3–7], p = 0.004) and were more likely to undergo mechanical ventilation (68% vs. 31%, p = 0.010). Sixty-three ibrutinib-treated patients were matched based on age and underlying malignancy with 63 controls receiving conventional chemotherapy from an historic cohort. Despite a higher median number of prior chemotherapy lines (2 [1–2] vs. 0 [0–2]; p

Abstract Individualize treatment after cardiac arrest could potentiate future clinical trials selecting patients most likely to benefit from interventions. We assessed the Cardiac Arrest Hospital Prognosis (CAHP) score for predicting reason for death to improve patient selection. Consecutive patients in two cardiac arrest databases were studied between 2007 and 2017. Reasons for death were categorised as refractory post-resuscitation shock (RPRS), hypoxic-ischaemic brain injury (HIBI) and other. We computed the CAHP score, which relies on age, location at OHCA, initial cardiac rhythm, no-flow and low-flow times, arterial pH, and epinephrine dose. We performed survival analyses using the Kaplan–Meier failure function and competing-risks regression. Of 1543 included patients, 987 (64%) died in the ICU, 447 (45%) from HIBI, 291 (30%) from RPRS, and 247 (25%) from other reasons. The proportion of deaths from RPRS increased with CAHP score deciles; the sub-hazard ratio for the tenth decile was 30.8 (9.8–96.5; p

Abstract Background Patients who are admitted to the intensive care unit (ICU) for severe acute exacerbations of chronic obstructive pulmonary disease (COPD) have poor outcomes. Although international clinical practice guidelines cautiously recommend the routine use of systemic corticosteroids for COPD exacerbations, data are scarce and inconclusive regarding their benefit for most severe patients who require mechanical ventilation in the ICU. Furthermore, corticosteroids may be associated with an increased risk of infection, ICU-acquired limb weakness, and metabolic disorders. Methods and analysis This study is an investigator-initiated, multicentre, randomized, placebo-controlled, double-blind trial comparing systemic corticosteroids to placebo during severe acute exacerbations of COPD in patients who require mechanical ventilation in French ICUs. A total of 440 patients will be randomized 1:1 to methylprednisolone (1 mg/kg) or placebo for 5 days, and stratified according to initial mechanical ventilation (non-invasive or invasive), pneumonia as triggering factor, and recent use of systemic corticosteroids (

Abstract Background Severe hypothyroidism (SH) is a rare but life-threatening endocrine emergency. Only a few data are available on its management and outcomes of the most severe forms requiring ICU admission. We aimed to describe the clinical manifestations, management, and in-ICU and 6-month survival rates of these patients. Methods We conducted a retrospective, multicenter study over 18 years in 32 French ICUs. The local medical records of patients from each participating ICU were screened using the International Classification of Disease 10th revision. Inclusion criteria were the presence of biological hypothyroidism associated with at least one cardinal sign among alteration of consciousness, hypothermia and circulatory failure, and at least one SH-related organ failure. Results Eighty-two patients were included in the study. Thyroiditis and thyroidectomy represented the main SH etiologies (29% and 19%, respectively), while hypothyroidism was unknown in 44 patients (54%) before ICU admission. The most frequent SH triggers were levothyroxine discontinuation (28%), sepsis (15%), and amiodarone-related hypothyroidism (11%). Clinical presentations included hypothermia (66%), hemodynamic failure (57%), and coma (52%). In-ICU and 6-month mortality rates were 26% and 39%, respectively. Multivariable analyses retained age > 70 years [odds ratio OR 6.01 (1.75–24.1)] Sequential Organ-Failure Assessment score cardiovascular component ≥ 2 [OR 11.1 (2.47–84.2)] and ventilation component ≥ 2 [OR 4.52 (1.27–18.6)] as being independently associated with in-ICU mortality. Conclusions SH is a rare life-threatening emergency with various clinical presentations. Hemodynamic and respiratory failures are strongly associated with worse outcomes. The very high mortality prompts early diagnosis and rapid levothyroxine administration with close cardiac and hemodynamic monitoring.

Abstract Natraemia is often abnormal in critically ill patients and may change rapidly during renal replacement therapy (RRT). This database study in a single intensive care unit (ICU) evaluated natraemia before and after the first RRT session for acute kidney injury. Of 252 patients who required RRT in 2018–2020, 215 were included. Prevalences were 53.9% for hyponatraemia (≤ 135 mmol/L) and 3.7% for hypernatraemia (> 145 mmol/L). Dialysate sodium was ≥ 145 mmol/L in 83% of patients. Median dialysis sodium gradient was 12 mmol/L, with a value above 16 mmol/L in 25% of patients. Median natraemia increased from 135 before to 140 mmol/L after RRT, the median hourly increase being faster than recommended, at 1.0 mmol/L [0.2–1.7]. By multivariate analysis, the only variable significantly associated with the RRT-induced natraemia change was the dialysis sodium gradient [odds ratio, 1.66; 95% confidence interval 1.39–2.10]. Pearson’s correlation coefficient between the gradient and the natraemia change was 0.57. When performing RRT in ICU patients, in addition to the haemodynamic considerations put forward in recommendations, the dialysis sodium gradient deserves careful attention in order to control natraemia variations. Studies to devise a formula for predicting natraemia variations might prove helpful to confirm our results.

IntroductionAcute exacerbation of chronic obstructive pulmonary disease (COPD) is a frequent cause of intensive care unit (ICU) admission. However, data are scarce and conflicting regarding the impact of systemic corticosteroid treatment in critically ill patients with acute exacerbation of COPD. The aim of the study was to assess the impact of systemic corticosteroids on the occurrence of death or need for continuous invasive mechanical ventilation at day 28 after ICU admission.MethodsIn the OutcomeReaTM prospective French national ICU database, we assessed the impact of corticosteroids at admission (daily dose ≥ 0.5 mg/kg of prednisone or equivalent during the first 24 hours ICU stay) on a composite outcome (death or invasive mechanical ventilation) using an inverse probability treatment weighting.ResultsBetween January 1, 1997 and December 31, 2018, 391 out of 1,247 patients with acute exacerbations of COPDs received corticosteroids at ICU admission. Corticosteroids improved the main composite endpoint (OR = 0.70 [0.49; 0.99], p = 0.044. However, for the subgroup of most severe COPD patients, this did not occur (OR = 1.12 [0.53; 2.36], p = 0. 770). There was no significant impact of corticosteroids on rates of non-invasive ventilation failure, length of ICU or hospital stay, mortality or on the duration of mechanical ventilation. Patients on corticosteroids had the same prevalence of nosocomial infections as those without corticosteroids, but more glycaemic disorders.ConclusionUsing systemic corticosteroids for acute exacerbation of COPD at ICU admission had a positive effect on a composite outcome defined by death or need for invasive mechanical ventilation at day 28.

Abstract Background To evaluate the association between ventilator type and hospital mortality in patients with acute respiratory distress syndrome (ARDS) related to COVID-19 (SARS-CoV2 infection), a single-center prospective observational study in France. Results We prospectively included consecutive adults admitted to the intensive care unit (ICU) of a university-affiliated tertiary hospital for ARDS related to proven COVID-19, between March 2020 and July 2021. All patients were intubated. We compared two patient groups defined by whether an ICU ventilator or a less sophisticated ventilator such as a sophisticated turbine-based transport ventilator was used. Kaplan–Meier survival curves were plotted. Cox multivariate regression was performed to identify associations between patient characteristics and hospital mortality. We included 189 patients (140 [74.1%] men) with a median age of 65 years [IQR, 55–73], of whom 61 (32.3%) died before hospital discharge. By multivariate analysis, factors associated with in-hospital mortality were age ≥ 70 years (HR, 2.11; 95% CI, 1.24–3.59; P = 0.006), immunodeficiency (HR, 2.43; 95% CI, 1.16–5.09; P = 0.02) and serum creatinine ≥ 100 µmol/L (HR, 3.01; 95% CI, 1.77–5.10; P

Abstract Background Patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-COV 2) and requiring intensive care unit (ICU) have a high incidence of hospital-acquired infections; however, data regarding hospital acquired bloodstream infections (BSI) are scarce. We aimed to investigate risk factors and outcome of BSI in critically ill coronavirus infectious disease-19 (COVID-19) patients. Patients and methods We performed an ancillary analysis of a multicenter prospective international cohort study (COVID-ICU study) that included 4010 COVID-19 ICU patients. For the present analysis, only those with data regarding primary outcome (death within 90 days from admission) or BSI status were included. Risk factors for BSI were analyzed using Fine and Gray competing risk model. Then, for outcome comparison, 537 BSI-patients were matched with 537 controls using propensity score matching. Results Among 4010 included patients, 780 (19.5%) acquired a total of 1066 BSI (10.3 BSI per 1000 patients days at risk) of whom 92% were acquired in the ICU. Higher SAPS II, male gender, longer time from hospital to ICU admission and antiviral drug before admission were independently associated with an increased risk of BSI, and interestingly, this risk decreased over time. BSI was independently associated with a shorter time to death in the overall population (adjusted hazard ratio (aHR) 1.28, 95% CI 1.05–1.56) and, in the propensity score matched data set, patients with BSI had a higher mortality rate (39% vs 33% p = 0.036). BSI accounted for 3.6% of the death of the overall population. Conclusion COVID-19 ICU patients have a high risk of BSI, especially early after ICU admission, risk that increases with severity but not with corticosteroids use. BSI is associated with an increased mortality rate.

IMPORTANCE:. Ventilator-associated pneumonia (VAP) frequently occurs in patients with cardiac arrest. Diagnosis of VAP after cardiac arrest remains challenging, while the use of current biomarkers such as C-reactive protein (CRP) or procalcitonin (PCT) is debated. OBJECTIVES:. To evaluate biomarkers’ impact in helping VAP diagnosis after cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS:. This is a prospective ancillary study of the randomized, multicenter, double-blind placebo-controlled ANtibiotherapy during Therapeutic HypothermiA to pRevenT Infectious Complications (ANTHARTIC) trial evaluating the impact of antibiotic prophylaxis to prevent VAP in out-of-hospital patients with cardiac arrest secondary to shockable rhythm and treated with therapeutic hypothermia. An adjudication committee blindly evaluated VAP according to predefined clinical, radiologic, and microbiological criteria. All patients with available biomarker(s), sample(s), and consent approval were included. MAIN OUTCOMES AND MEASURES:. The main endpoint was to evaluate the ability of biomarkers to correctly diagnose and predict VAP within 48 hours after sampling. The secondary endpoint was to study the combination of two biomarkers in discriminating VAP. Blood samples were collected at baseline on day 3. Routine and exploratory panel of inflammatory biomarkers measurements were blindly performed. Analyses were adjusted on the randomization group. RESULTS:. Among 161 patients of the ANTHARTIC trial with available biological sample(s), patients with VAP (n = 33) had higher body mass index and Acute Physiology and Chronic Health Evaluation II score, more unwitnessed cardiac arrest, more catecholamines, and experienced more prolonged therapeutic hypothermia duration than patients without VAP (n = 121). In univariate analyses, biomarkers significantly associated with VAP and showing an area under the curve (AUC) greater than 0.70 were CRP (AUC = 0.76), interleukin (IL) 17A and 17C (IL17C) (0.74), macrophage colony-stimulating factor 1 (0.73), PCT (0.72), and vascular endothelial growth factor A (VEGF-A) (0.71). Multivariate analysis combining novel biomarkers revealed several pairs with p value of less than 0.001 and odds ratio greater than 1: VEGF-A + IL12 subunit beta (IL12B), Fms-related tyrosine kinase 3 ligands (Flt3L) + C–C chemokine 20 (CCL20), Flt3L + IL17A, Flt3L + IL6, STAM-binding protein (STAMBP) + CCL20, STAMBP + IL6, CCL20 + 4EBP1, CCL20 + caspase-8 (CASP8), IL6 + 4EBP1, and IL6 + CASP8. Best AUCs were observed for CRP + IL6 (0.79), CRP + CCL20 (0.78), CRP + IL17A, and CRP + IL17C. CONCLUSIONS AND RELEVANCE:. Our exploratory study shows that specific biomarkers, especially CRP combined with IL6, could help to better diagnose or predict early VAP occurrence in cardiac arrest patients.

Se evaluó la producción de celulasas del Trichoderma reesei Rut C-30 (ATCC 56765) por fermentación sumergida con diferentes substratos celulósicos (paja de arroz, celulosa como única fuente de carbono y una mezcla de celulosa y hemicelulosa comerciales). Previamente se estudió el crecimiento y la esporulación del hongo en placas de agar papa con diferentes concentraciones de glucosa y diferentes variaciones de la solución mineral de Mandels y Weber (1969) para lograr la germinación y desarrollo de las conidiosporas de T. reesei. Las fermentaciones se realizaron por duplicado en erlenmeyers de 250 mL con 60 mL de solución mineral al 1% p/v de concentración de substrato, 29°C y agitación de 200 rpm por 120 h, y en un fermentador de 5L Modelo Bioflo III con paja de arroz como substrato, bajo condiciones controladas de temperatura (29°C), agitación (150 rpm) y oxigenación (20% de saturación). La naturaleza química de la paja de arroz (6,75% de proteínas) y de los substratos comerciales (0% de proteínas; control) empleados en las fermentaciones, jugaron un papel importante en el pH final desarrollado durante las fermentaciones. Sin embargo, la diferencia de los valores finales de pH (3,31 promedio para los substratos comerciales y 6,38 para la paja de arroz), no condicionó grandemente el crecimiento y la producción de celulasas, a pesar que el crecimiento fue mucho mejor en los substratos comerciales. La producción de celulasas fue mayor en las fermentaciones con la mezcla comercial (0,62 UI/mL), seguido por la celulosa amorfa como única fuente de carbono (0,57 UI/mL) y por la paja de arroz (0,51 UI/mL). La producción de celulasas en el fermentador (0,38 UI/mL) fue menor a la encontrada en el estudio en erlenmeyers.Cellulase production by the fungus Trichoderma reesei Rut C-30 (ATCC 56765) at initial pH 4.8, with different cellulosic substrates (rice straw, cellulose as the only carbon source, and a mixture of commercial cellulose and hemicellulose), was investigated. Previously, growth and sporulation of the fungus on potato agar plates with different glucose concentrations, and different variations of the Mandels and Weber´s mineral solution (1969) for the germination and development of conidiospores of T. reesei, were studied. Fermentations were carried out in duplicate, in 250 mL Erlenmeyer flasks with 60 mL of mineral solution, 1% w/v substrate, 29°C and agitation at 200 rpm for 120 h, and in a 5L Bioflo III fermentor with rice straw as the substrate, under controlled temperature (29°C), agitation (150 rpm) and aeration (20% saturation) conditions. The chemical nature of the rice straw (6.75% protein) and the commercial substrates (0% protein, control substrate) used in the fermentations played a major role in the final pH. However, the difference between the pH values reached at the end of the fermentations (between 3.28 and 6.38), did not greatly affect the growth and cellulase production by the fungus in spite of the fact that the growth was much greater with the commercial substrates. The cellulase production was higher in the fermentations with the commercial mixture (0.62 IU/mL), followed by those with amorphous cellulose as the only carbon source (0.57 IU/mL) and rice straw (0.51 IU/mL). Cellulase production in the fermentor (0.38 IU/mL) was lower than that found in the flasks study.

Se estudió el tiempo de reducción decimal (D) de Rhodotorula rubra (R. rubra) y Candida intermedia (C. intermedia) a diferentes concentraciones de sólidos solubles 12, 36 y 52 ºBrix, en jugo de naranja. Las temperaturas utilizadas fueron 63, 64, 65, 66 y 67 ºC. Los D obtenidos siguiendo el método de tubo de Stumbo modificado, para R. rubra fueron desde un mínimo de 3,1 seg para 36 ºBrix a 67ºC hasta un máximo de 209 seg para 52 ºBrix a 63ºC. Para C. intermedia, el D mínimo obtenido fue 3,2 seg. a 12 ºBrix a 64ºC y el máximo D obtenido fue de 6 seg a 52 ºBrix a 64ºC. Se evidenció que a medida que aumenta la concentración de sólidos solubles aumenta la resistencia térmica de las levaduras estudiadas, presentando R. rubra la mayor resistencia térmica a 52 ºBrix. C. intermedia es más osmotolerante que R. rubra pero más sensible al calor en altas concentraciones de azúcaresThermal resistance of yeasts in orange juice at different concentrations of soluble solids. Thermal decimal reduction time (D) of Rhodotorula rubra (R. rubra) and Candida intermedia (C. intermedia) at 63, 64, 65, 66 and 67ºC was studied, at soluble solids concentrations of 12, 36 and 52 ºBrix in orange juice. Experiments were conducted according to Stumbo method. D values for R. rubra were obtained in a range of 3.1 s for D 67ºC at 36 ºBrix as a minimum to 209 s at 64ºC and 52 ºBrix as a maximum. For C. intermedia, the minimum D value was 3.2 s at 64ºC and 12 ºBrix and the maximum was 6 s at 64ºC and 52 ºBrix. It can be noticed that as the concentration of soluble solids increases, the thermal resistance of the yeasts increases. R. rubra exhibits its highest thermal resistance at 52 ºBrix for all temperatures. C. intermedia shows more osmotolerancy that R. rubra but it is more sensitive to heat at high sugar concentrations

In this study a method that uses pressurization and depressurization with ammonia processing (PDA) was applied to rice straw samples. The effect of PDA on the structure of rice straw samples with various moisture contents (15%, 35% and 60%); different treatment times with ammonia (0 min, 6 min and 20 min) and four combinations of addition and treatment times of ammonia (1-0 min, 1-5 min, 4-0 min, 4-5 min) was determined. Morphological changes were detected by Scanning Electron Microscope. PDA treatment produced noticeable structural changes in rice straw. As moisture content Increased there were more cellular architectural losses of parenchyma tissue. As ammonia treatment time increased, more shredding of cellulose fibrils appeared and the higher the ammonia addition time and the treatment time combination, the higher the parenchymal and epidermal cells collapse as well as that of the epidermal wax.

A stainless steel bioreactor was redesigned in order to facilite the production of microbial protein by solid-state fermentation. A double-helix stirrer was built to replace a blade-stirrer. Mixing time was set at 12 min every two hours. An air-manifold was built and installed at the bottom of the reactor. It allowed uniform bubbling in the water reservoir, providing a continuous flow of saturated air through the biomass. The intermittent mixing provided it a uniform substrate with minimun damage to the mycelial biomass. Along with the saturated air, allowed removal of the metabolic heat produced and prevented formation of dead zones in the biomass. A fermentation with Trichoderma reesei QM 9414 on water-treated sugar cane bagasse was carried out to test the operation of the bioreactor. The fermented product reached 7% crude protein at 48 h. A maximum of 10.96% was reached at 96h. This value was much higher than the laboratory value, confirming that the design allows a more efficient fermentation process.

Cellulase production by the fungus Trichoderma reesei Rut C-30 (ATCC 56765) at initial pH 4.8, with different cellulosic substrates (rice straw, cellulose as the only carbon source, and a mixture of commercial cellulose and hemicellulose), was investigated. Previously, growth and sporulation of the fungus on potato agar plates with different glucose concentrations, and different variations of the Mandels and Weber´s mineral solution (1969) for the germination and development of conidiospores of T. reesei, were studied. Fermentations were carried out in duplicate, in 250 mL Erlenmeyer flasks with 60 mL of mineral solution, 1% w/v substrate, 29°C and agitation at 200 rpm for 120 h, and in a 5L Bioflo III fermentor with rice straw as the substrate, under controlled temperature (29°C), agitation (150 rpm) and aeration (20% saturation) conditions. The chemical nature of the rice straw (6.75% protein) and the commercial substrates (0% protein, control substrate) used in the fermentations played a major role in the final pH. However, the difference between the pH values reached at the end of the fermentations (between 3.28 and 6.38), did not greatly affect the growth and cellulase production by the fungus in spite of the fact that the growth was much greater with the commercial substrates. The cellulase production was higher in the fermentations with the commercial mixture (0.62 IU/mL), followed by those with amorphous cellulose as the only carbon source (0.57 IU/mL) and rice straw (0.51 IU/mL). Cellulase production in the fermentor (0.38 IU/mL) was lower than that found in the flasks study.

Microorganismos no patógenos aislados del queso tipo Palmita comercial pertenecientes a los géneros Enterococcus, Streptococcus, Lactobacillus y Enterobacter, se utilizaron en cultivos iniciadores simples y mixtos, con el fin de seleccionar los más adecuados para elaborar queso tipo Palmita con leche pasteurizada. Se elaboraron quesos con leche pasteurizada inoculados con las cepas bacterianas en cultivos iniciadores simples y quesos con leche cruda como control. A dichos quesos se les hicieron determinaciones de pH. acidez titulable y análisis sensorial. Como resultado de esto, se hizo una preselección de las cepas. Estas cepas preseleccionadas se utilizaron posteriormente en cultivos mixtos en la elaboración de queso con leche pasteurizada. A los quesos elaborados se les determinó pH, acidez titulable y el grado de aceptabilidad, resultando dos mezclas constituidas por Enterococcus faecaiis y Enterobacter cloacae, y Lactobacillus casei y Enterobacter cloacae, como las mas adecuadas para producir las características de sabor, color, textura y ";;ojos";; típicos de queso tipo Palmita.

Se determinó la producción de diacetilo por parte de once cepas de Enterococcus faecalis, siete cepas de Lactobacillus casei y cuatro cepas de Enterobacter aerogenes, en cultivos simples y múltiples con leche descremada reconstituida al 10% estéril durante 18 h a 35°C. Cada cultivo fue sometido a destilación para recuperar el diacetilo formado. 0,5 ml de o-fenilendiamina y 2 ml de HCL se adicionaron a 10 ml del destilado para obtener valores de absorbancia a 340 nm, en un espectrofotómetro- UV Perkin-Elmer, lambda 3 β. Las concentraciones de diacetilo fueron obtenidas de una curva estándar. Los resultados revelaron una mayor producción promedio de diacetilo por todas las cepas en cultivos simples (12,0, 13,2 y 9.4 ppm de E. faecalis, L. casei y E. aerogenes, respectivamente) en comparación con los cultivos múltiples (4,5 ppm). Se observaron diferencias significativas entre cepas de una misma especie (p Ë‚ 0,05). De acuerdo a los resultados, las cepas de E. faecalis Ef7 y Ef11, L. casei L1 ,L2 y L3 y E. aerogenes Eal, fueron las que produjeron mayores niveles de diacetilo y podrían ser las cepas más recomendables como constituyentes de cultivos iniciadores simples y múltiples utilizados en la elaboración del queso tipo Palmita con leche pasteurizada.

Once cepas de Enterococcus faecalis, siete de Lactobacillus casei;, cuatro de Enterobacter aerogenes y cuatro de Enterobacter cloacae aisladas de queso tipo Palmita comercial se cultivaron en leche descremada estéril al 10% en forma de cultivos simples con el fin de seleccionar cepas mayor productoras de acidez titulable en el caso de los Enterococcus y Lactobacillus. Con respecto a los Enterobacter se seleccionaron las de menor producción. Estas cepas se utilizaron posteriormente en cultivos múltiples los cuales se evaluaron en su producción de acidez titulable. Los resultados mostraron diferencias significativa (P < 0.05) entre cepas de una misma especie en cultivos simples, y entre combinaciones de cepas en cultivos múltiples. Las cepas de Enterobacter y Lactobacillus produjeron más ácidos que las cepas de Enterccoccus. Las cepas seleccionadas fueron: E faecalis (4 cepas), L. casei (3 cepas) y E, aerogenes (2 cepas). Los cultivos múltiples resultaron con mayores niveles de acidez que los cultivos simples, y a su vez no se observaron diferencias significativas entre los cultivos múltiples analizados. Estos resultados sugieren que los cultivos múltiples pueden ser utilizados como cultivos iniciadores debido a la garantía de mayor actividad fermentativa.

Se estudió a nivel de planta piloto el efecto de diferentes concentraciones de penicilina y estreptomicina sobre la producción de ácido de once cepas de Enterococcus faecalis y siete cepas de Lactobacillus casei usadas como cultivos iniciadores en la manufactura de queso tipo Palmita con leche pasteurizada. Los microorganismos fueron cultivados en leche descremada reconstituida estéril, libre de antibióticos y conteniendo concentraciones conocidas de penicilina desde 0,008 a 1000 U.I./ml y 0,007 a 1 mg/ml de estreptomicina. La actividad de los cultivos fue medida en términos de acidez titulable después de una incubación a 35°C durante 18 h. Los resultados mostraron que el 18,2% de los cultivos con E. faecalis resultaron resistentes a concentraciones de 20 U.I./ml de penicilina, mientras que resultaron inhibidos a concentraciones de 40 U.I./ml; el 63,6% de los mismos cultivos fueron resistentes a concentraciones de 0,07 mg/ml de estreptomicina, mientras que fueron inhibidas por 0.1 mg/ml. El 28,6% de los cultivos con L. casei fueron resistentes a 10 U.I./ml de penicilina y el 42,9% fueron resistentes a 0.05 mg/ml de estreptomicina. Los cultivos con L. casei fueron más susceptibles a la penicilina y estreptomicina que los cultivos con E. faecalis. Sin embargo, hubo cepas de enterococos y lactobacilos que fueron muy susceptibles a ambos antibióticos, 5 U.I./ml y 0,5 U.I./ml de penicilina para los enterococos y lactobacilos, respectivamente, y 0,5 mg/ml y 0,03 mg/ml de estreptomicina para enterococos y lactobacilos, respectivamente. Se observaron variaciones entre especies y entre cepas de la misma especie. Las cepas de E. faecalis Ef8 y Ef9 y las cepas de L. casei L1 y L3, constituyen las cepas más recomendables en cultivos iniciadores en la elaboración de queso tipo Palmita debido a su característica de mayor resistencia a los antibióticos analizados.

Veinte muestras de queso venezolano tipo Palmita, proveniente de dos expendios comerciales en la ciudad de Maracaibo, fueron analizadas en su contenido de diacetilo durante un lapso experimental de cinco semanas. Las muestras de queso fueron sometidas a destilación para recuperar el diacetilo formado. A 10 ml del destilado de cada queso, se le adicionó 0,5 ml de o-fenilendiamina y 2 ml de HCl para obtener valores de absorbancia del diacetilo a 340 nm, en un espectrofotómetro- UV Perkin-Elmer, lambda 3-b. La concentracion de diacetilo en cada muestra de queso se obtuvo a través de una curva estándar. Los resultados revelaron diferencias significativas (P < 0,05) entre los quesos analizados. Las concentraciones de diacetilo variaron entre niveles de 0,92 y 6,92 ppm, los cuales están dentro del rango encontrado en los quesos Emmental, Cheddar y Parmesano.

A cultivos simples y múltiples con leche descremada reconstituida al 10% estéril, constituidos por once cepas de Enterococcus faecalis, siete cepas de Lactobacillus casei y cuatro cepas de Enterobacter aerogenes, se les determinó la producción de acetaldehído, utilizando la técnica cromatográfica (GC) headspace. Los cultivos fueron previamente colocados en baño de agua a 60°C para permitir el paso del acetaldehído a su estado gaseoso. Los resultados mostraron la producción activa de acetaldehído por parte de las cepas bacterianas en cultivos simples y múltiples con diferencias significativas entre especies y entre cepas de la misma especie (P < 0,05). Las cepas de E. aerogenes Ea1 y Ea2 y de E. faecalis Ef7, Ef8, Ef9 y Ef10 produjeron los mayores niveles de acetaldehído en cultivos simples (5,8-6,0 ppm y 2,6-2,8 ppm, respectivamente) mientras que las cepas de L. casei produjeron los niveles menores (0,4-0,6 ppm). En cultivos múltiples, las combinaciones Enterococcus-Enterobacter produjeron más acetaldehído (2,9 ppm, P < 0,05) que las combinaciones Lactobacillus-Enterobacter (2,5 ppm) y las Enterococcus-Lactobacillus-Enterobacter (2,1 ppm). Debido a que todas las combinaciones produjeron concentraciones relativamente similares de acetaldehído, se recomienda el uso de cualquiera de ellas para garantizar el sabor y olor característicos del queso tipo Palmita.

Ten fresh cheese whey samples from local plants were analyzed to detect bacteriophages and evaluate the phage effects on the titratable acidity production in 10% sterile skim milk of eleven Enterococcus faecalis and seven Lactobacillus casei strains, which can be used as starters for the manufacture of Palmita-type Venezuelan cheese. The results showed that four whey samples were positive for phages, with lytic activity demonstrated by the presence of plaques from 0.2 to 0.3 mm in diameter on both M17 and MRS agar plates. The fermentative activity tests showed that 91% of the cultures with E. faecalis strains and 57% with L. casei strains were resistant to the isolated phages. Variations were observed between species as well as between strains of the same species. Such variability suggests the use of strains resistant to bacteriophages in order to guarantee the cheese quality.

Diferentes salchichones comerciales fueron utilizados para aislar y caracterizar las bacterias lácticas presentes en ellos, medir la eficiencia fermentativa de estas bacterias frente a diferentes azúcares, y a diferentes temperaturas y, finalmente, preparar un cultivo mixto para ser utilizado en la elaboración de un producto cárnico fermentado. La eficiencia del cultivo preparado en el laboratorio (L) se comparó con la eficiencia de un cultivo importado (I). Para esto se formularon y prepararon productos conforme al procedimiento utilizado por la industria. Se comparó la velocidad de caída del pH, la pérdida de peso durante todo el proceso y la calidad microbiológica de los productos finales. Especies de Lactobacilos tales como L. plantarum, L. fermentum. L. acidophilus y L. viridescens fueron aislados de los diferentes salchichones comerciales. Los lactobacilos homofermentativos aislados fermentaron indistintamente la glucosa y la sacarosa y fueron más eficientes a 37°C que a 25°C. El cultivo L fue tan eficiente como el cultivo I en bajar el pH de los productos hasta un valor deseable (4.9 para el L y 5.1 para el I) durante los primeros cinco días. Ambos cultivos originaron una perdida rápida de peso durante los primeros seis días y luego una perdida lenta del séptimo al veinteavo día, hasta obtener valores finales al cabo de 28 días y para el tratamiento L de 30.2% y para I de 29.4%. Los dos productos cumplieron los requisitos microbiológicos establecidos por COVENIN.

Para evaluar el efecto de la incorporación de la harina de follaje de yuca (HFY) en niveles crecientes (0; 2,5; 5 y 7,5%) en raciones alimenticias para pollos de engorde sobre las características al sacrificio y el rendimiento en canal y en cortes, se usaron 32 pollos de engorde, hembras de la raza Cobb de 42 días de edad. El análisis de la varianza detectó efectos significativos (P

El presente estudio determinó el efecto de 0,1% de cultivo de levadura Saccharomyces cerevisiae (CSc) y 2 mg/kg de selenio (Se) sobre los índices productivos y concentración de proteínas totales en pollos de engorde que recibieron dietas con 0,07 mg/kg de aflatoxina B1 (AFB1). Un total de 480 pollos de engorde, de un día de nacidos, fueron asignados al azar para recibir 8 tipos de dietas durante 42 días. Se registró el peso de las aves (P), consumo de alimento (C), conversión de alimento (CV), ganancia de peso corporal (GPC), mortalidad (M) y a los 42 días se tomó suero sanguíneo de cada grupo para determinar la concentración de proteínas totales (PT). Las dietas correspondieron a los siguientes tratamientos (T) T1: grupo control que consiste en alimento comercial (AC) sin niveles detectables de aflatoxina; T2: AC + AFB1; T3: AC + CSc; T4: AC + AFB1 + CSc; T5: AC + Se; T6: AC + AFB1 + Se; T7: AC + CSc + Se; T8: AC + AFB1 + CSc + Se. La inclusión de CSc y/o Se en dietas con o sin AFB1 no alteró (P>0,05) el P, GPC, CV PT. El C incrementó (P£0,01) con la inclusión de CSc y/o Se en el alimento con AFB1 (T4, T6, T8), con respecto a los pollos que recibieron CSc y/o Se sin AFB1 (T3, T5, T7). La M en aves que recibieron AFB1 (T2, T4, T6, T7), incrementó (P

Se evaluó la producción de celulasas del Trichoderma reesei Rut C-30 (ATCC 56765) por fermentación sumergida con diferentes substratos celulósicos (paja de arroz, celulosa como única fuente de carbono y una mezcla de celulosa y hemicelulosa comerciales). Previamente se estudió el crecimiento y la esporulación del hongo en placas de agar papa con diferentes concentraciones de glucosa y diferentes variaciones de la solución mineral de Mandels y Weber (1969) para lograr la germinación y desarrollo de las conidiosporas de T. reesei. Las fermentaciones se realizaron por duplicado en erlenmeyers de 250 mL con 60 mL de solución mineral al 1% p/v de concentración de substrato, 29°C y agitación de 200 rpm por 120 h, y en un fermentador de 5L Modelo Bioflo III con paja de arroz como substrato, bajo condiciones controladas de temperatura (29°C), agitación (150 rpm) y oxigenación (20% de saturación). La naturaleza química de la paja de arroz (6,75% de proteínas) y de los substratos comerciales (0% de proteínas; control) empleados en las fermentaciones, jugaron un papel importante en el pH final desarrollado durante las fermentaciones. Sin embargo, la diferencia de los valores finales de pH (3,31 promedio para los substratos comerciales y 6,38 para la paja de arroz), no condicionó grandemente el crecimiento y la producción de celulasas, a pesar que el crecimiento fue mucho mejor en los substratos comerciales. La producción de celulasas fue mayor en las fermentaciones con la mezcla comercial (0,62 UI/mL), seguido por la celulosa amorfa como única fuente de carbono (0,57 UI/mL) y por la paja de arroz (0,51 UI/mL). La producción de celulasas en el fermentador (0,38 UI/mL) fue menor a la encontrada en el estudio en erlenmeyers.