Abstract Plant growth-promoting bacteria (PGPB) that inhabit root rhizosphere of plants are of great agricultural importance due to their ability to produce phytohormones during root colonization. These phytohormones produce physiological changes in the plant that favor a greater absorption of nutrients, promote growth and increase production. This study analyzed the effect of inoculation of two of these bacteria, Azospirillum sp. and Pseudomonas fluorescens, under field conditions representative of the Andean Highlands. The experiment was carried out using flour corn seed of the INIAP-101 variety in a randomized complete block design with six repetitions. The treatments corresponded to: T1 (Azospirillum sp.), T2 (P. fluorescens), T3 (Azospirillum sp. and P. fluorescens), T4 (control, conventional chemical fertilization) and T5 (absolute control). The application of these bacteria significantly increased (p<0.05) the root length, the diameter of the cob, and the yield of fresh corn (“elotes” or “choclos”). The combined inoculation of these bacteria (T3) obtained the highest yield, with 19.70 t ha−1 of fresh corn; while the chemical control and the absolute control got 17.12 and 13.58 t ha−1 of fresh corn, respectively. The economic analysis of T3 reported a benefit/cost of 1.35, which indicates that the synergism of these two bacteria could be a sustainable strategy to improve yields and reduce the use of chemical fertilizers for corn production in the Andean region.

Resumen Las bacterias benéficas que habitan la rizósfera de las plantas son de gran interés agrícola debido a su capacidad para producir fitohormonas durante la colonización radicular. Estas fitohormonas producen cambios fisiológicos en la planta que favorecen una mayor absorción de nutrientes que provocan un rápido crecimiento vegetativo y una mayor producción. Esta investigación tuvo como objetivo evaluar el efecto de la inoculación de dos de estas bacterias, Azospirillum sp. y Pseudomonas fluorescens en el cultivo de maíz harinoso bajo condiciones de campo típicas de la región alto andina. El experimento se realizó utilizando semilla de maíz harinoso de la variedad INIAP-101 con un diseño de bloques completos al azar y seis repeticiones. Los tratamientos correspondieron a: T1 (Azospirillum sp.), T2 (P. fluorescens), T3 (Azospirillum sp. y P. fluorescens), T4 (testigo con fertilización química convencional) y T5 (testigo absoluto). La aplicación de estas bacterias incrementó de manera significativa (p<0,05) la longitud de raíz, el diámetro de la mazorca y el rendimiento del maíz tierno (elotes o choclos). La inoculación combinada de estas bacterias (T3) obtuvo el mayor rendimiento con 19,70 t ha−1 de choclos, mientras que el testigo químico y el testigo absoluto obtuvieron 17,12 y 13,58 t ha−1 de choclos, respectivamente. El análisis económico de T3 reportó un coste/beneficio de 1,35, lo cual indicó que el sinergismo de estos dos géneros podría ser una estrategia sostenible para mejorar los rendimientos y reducir el uso de fertilizantes químicos en el cultivo de maíz de la región Andina.

Abstract Bovine mastitis is a disease that affects the farms of small and medium producers in the cantons of Cayambe and Pedro Moncayo, Pichincha Province-Ecuador. Treating this disease is not easy due to the different microorganisms that cause it. This study focused on the molecular determination by means of polymerase chain reaction (PCR) of the etiological agents of mastitis, having multiple advantages when recognizing family, gender and species of microorganisms. It is a method capable of detecting resistance genes of antibiotics, an important analysis when diagnosing and treating diseases. The aim of this research is to identify bacteria causing bovine mastitis by using biochemical and molecular tests. Biochemical tests such as: Gram staining, Catalase, Coagulase, and Mannitol Salt Agar were efficient to obtain pure strains and determine the gender of some bacteria. Specific primers (RNA16S) were used for the molecular identification of 9 etiological agents causing the disease in the productive units. The microorganisms found were Staphylococcus pasteuri, Staphylococcus warneri, Staphylococcus sp., Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus saprophyticus, Sphingomonas sp., Streptococcus dysgalactiae, Streptococcus uberis, mostly present in clinic mastitis. To detect resistance genes, specific primers were used, of which 7 samples presented the gene for resistance to blaTEM (β-lactam) and 6 samples presented the gene for resistance to tetA (tetracyclines). Multi-resistance was identified in the species Staphylococcus pasteuri, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus uberis, Sphingomonas sp.

Resumen La mastitis bovina es una enfermedad que afecta a las ganaderías de pequeños y medianos productores de los cantones Cayambe y Pedro Moncayo, Provincia de Pichincha-Ecuador. El tratamiento de esta enfermedad resulta complicado debido a la variedad de microorganismos que la provocan. El presente estudio se enfocó en la determinación molecular por medio de reacción en cadena de la polimerasa (PCR) de los agentes etiológicos de la mastitis. Esta técnica presenta múltiples ventajas al reconocer familia, género y especie de microorganismos, y es un método capaz de detectar genes de resistencia de antibióticos, lo que resulta importante al momento de diagnosticar y tratar enfermedades. El objetivo de esta investigación se centró en la identificación de bacterias causantes de la mastitis bovina, utilizando pruebas bioquímicas y moleculares. Las pruebas bioquímicas como tinción Gram, Catalasa, Coagulasa, y Agar Manitol Sal fueron eficientes para obtener cepas puras y determinar el género de algunas bacterias. Se utilizaron primers específicos (RNA16S) para la identificación molecular de 9 agentes etiológicos causantes de la enfermedad en las unidades productivas. Los microorganismos encontrados fueron; Staphylococcus pasteuri, Staphylococcus warneri, Staphylococcus sp., Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus saprophyticus, Sphingomonas sp., Streptococcus dysgalactiae, Streptococcus uberis, la mayoría presentes en mastitis clínica. Para detectar genes de resistencia se utilizaron primers específicos, de los cuales 7 muestras presentaron el gen para resistencia a blaTEM (β-lactámicos) y 6 muestras presentaron el gen para resistencia a tetA (tetraciclinas). Se identificó multirresistencia en las especies: Staphylococcus pasteuri, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus uberis, Sphingomonas sp.

Abstract The development of living beings depends on the health and chemical quality of the available water. In recent years, the importance of the environment in the spread of resistant and multi-resistant bacteria to antibiotics has been observed, a situation that has placed the problem of antibiotic resistance on a broader level and which is being studied from the perspective “One Health”. The objective of this work was to determine the presence of multi-resistant bacteria to antibiotics in irrigation water samples from the Chibunga river. Fourteen water samples of 100 mL each were collected in sterile containers and aseptically, were kept under refrigeration until analysis in the laboratory. Each sample was seeded by the surface seeding method on blood, cystine electrolyte deficient, MacConkey, Salmonella-Shigella and thiosulfate citrate bile sucrose agars, incubating in all cases at a temperature of 37 °C for a maximum time of 48 hours. The identification of bacterial colonies was carried out through physiological and biochemical tests according to the identification schemes indicated by MacFaddin. The resistance/sensitivity to antibiotics of the identified colonies was carried out by the disk diffusion method of Kirby Bauer. Two species of multi-resistant bacteria were identified, including strains of Morganella morgani and Plesiomonas shigelloides resistant to antibiotics of clinical use such as ceftazidime, aztreonam, ciprofloxacin, nalidixic acid and trimethoprim-sulfamethoxazole. The results show that the waters of Chibunga river harbor bacteria with multi-resistance to antimicrobials, representing a contamination risk of agricultural products harvested in its vicinity, as well as for the people who use these waters.

Resumen El bienestar y desarrollo de los seres vivos depende de la calidad sanitaria y química del agua disponible. En los últimos años se ha venido observando la importancia del ambiente en la diseminación de bacterias resistentes y multirresistentes a los antibióticos, situación que ha colocado la problemática de la resistencia en un plano más amplio y que se está estudiando desde la perspectiva “One Health”. En este sentido, el objetivo del presente trabajo fue determinar la presencia de bacterias multirresistentes a los antibióticos en muestras de agua de riego provenientes del río Chibunga. Se recolectaron 14 muestras de agua de un volumen de 100 mL cada una, en envases estériles y de manera aséptica, las cuales fueron conservadas bajo refrigeración hasta su análisis en el laboratorio. Cada muestra fue sembrada por el método de siembra en superficie en los agares cistina electrolito deficiente, MacConkey, Salmonella-Shigella, tiosulfato citrato bilis sacarosa y agar sangre, incubándose en todos los casos a una temperatura de 37 °C durante un tiempo máximo de 48 horas. La identificación de las colonias bacterianas se realizó mediante pruebas fisiológicas y bioquímicas de acuerdo con los esquemas de identificación indicados por MacFaddin. El perfil de susceptibilidad a los antibióticos de las colonias identificadas se realizó por el método de difusión en disco de Kirby Bauer. Se lograron identificar 2 especies de bacterias multirresistentes, entre ellas, cepas de Morganella morganii y Plesiomonas shigelloides resistentes a antibióticos de uso clínico como ceftazidima, aztreonam, ciprofloxacino, ácido nalidíxico y trimetroprim-sulfametoxazol. Los resultados muestran que las aguas del río Chibunga albergan bacterias con multirresistencia a los antimicrobianos, representando un riesgo de contaminación de los productos agrícolas cosechados en sus inmediaciones, así como para las personas que utilizan estas aguas.

Abstract The use of fungi and bacteria with pathogenic capacity towards insects is considered a sustainable agroecological alternative for efficient pest control, as they are microorganisms of easy production in industrial scale, formulation and use. Therefore, the objective was to evaluate four entomopathogenic formulations in the control of Brevicoryne brassicae L., a key pest of cabbage (Brassica oleracea L.), in a randomized complete block design with 4 treatments, plus an absolute control and 4 replicates. The variables evaluated were the number of dead and live aphids per plant and the number of infested plants. The commercial formulations Biosafe, BesT-K, Metarrizo and Yurak containing strains of Bacillus subtilis, Bacillus thuringiensis var kurstaki (Btk), Metarhizium anisopliae and Bauveria bassiana respectively, are the ones that were used by spray application to the crop in two seasons: planting, season August-December 2019 and August-December 2021. Among the results, M. anisopliae was recorded with up to 91.11 % efficiency, followed by B. bassiana with 89.50 % and Bs with 79.38 % in the reduction of populations under field conditions. In the laboratory, Btk and M. anisopliae reached 100 % mortality in a period of seven days, so it is concluded that in the medium term, entomopathogenic fungi in the field are more efficient in aphid control; however, in controlled conditions Btk is also efficient.

Resumen El uso de hongos y bacterias con capacidad patogénica hacia los insectos se considera una alternativa agroecológica sostenible de lucha eficiente contra las plagas por ser microorganismos de fácil producción en escala industrial, formulación y uso; entonces, el objetivo ha sido evaluar cuatro formulados entomopatógenos en el control de Brevicoryne brassicae L, plaga clave de la col (Brassica oleracea L.), en diseño de bloques completos al azar de 4 tratamientos, sumado un testigo absoluto y 4 réplicas, siendo las variables evaluadas la cantidad de pulgones muertos y vivos por planta y cantidad de plantas infestadas. Los formulados comerciales Biosafe, BesT-K, Metarrizo y Yurak que contenían cepas de Bacillus subtilis, Bacillus thuringiensis var kurstaki (Btk), Metarhizium anisopliae y Bauveria bassiana, respectivamente, son los que fueron utilizados mediante la aplicación por aspersión al cultivo en dos épocas de siembra, temporada agosto-diciembre 2019 y agosto-diciembre 2021. Entre los resultados se registró al M. anisopliae con hasta 91,11 % de eficiencia, seguida por B. bassiana con 89,50 % y Bs con 79,38 % en la reducción de las poblaciones en condiciones de campo; en laboratorio el Btk y M. anisopliae alcanzaron el 100 % de mortalidad en un lapso de siete días, por lo que se concluye que a mediano plazo los hongos entomopatógenos en campo resultan ser más eficientes en el control del pulgón, sin embargo, en condiciones controladas el Btk también es eficiente.

ABSTRACT Due to the diversification of dairy products developed in the state of Falcón, the introduction of a fermented dairy product derived from yogurt combined with Aloe vera gel, a traditional crop of the region, is novel due to its nutritional properties and health benefits. The objective of this research was to evaluate the quality of a dairy drink with fermented aloe according to current regulations. Important authors such as Tamime and Robinson 1, Morillo and Toyo 2, Méndez and Romero 3 were taken as references. Product elaboration runs were carried out on a laboratory scale, in order to establish the adequate proportions of the fruity Aloe gel by mixing fruit pulp, sugar and Aloe gel, the most accepted being the 1:1:1 ratio. The physicochemical and microbiological characterization of the raw material and the finished product was carried out using the COVENIN standards and organoleptic tests to untrained judges to ensure the acceptance of the product, from which a fermented milk drink was obtained with the addition of 50 % gel of Fruity Aloe with a pH of 4,51; a titratable acidity of 0,837 % lactic acid; 3,64 % fat and 12,92 % non-fat solids. Regarding the microbiological quality, few yeasts and the absence of coliform bacteria were found, which complies with the physicochemical and microbiological requirements demanded by the regulations, allowing the obtaining of a quality product suitable for human consumption based on natural raw materials.

RESUMEN Debido a la diversificación de los productos de origen lácteo desarrollados en el estado Falcón, la introducción de un producto lácteo fermentado derivado del yogurt combinado con gel de Aloe vera, cultivo tradicional de la región, es novedoso por sus propiedades alimenticias y beneficios a la salud. Esta investigación tuvo como objetivo evaluar la calidad de una bebida láctea fermentada con gel de Aloe frutado según la normativa vigente. Se tomaron como referencias importantes autores como Tamime y Robinson, (1) Morillo y Toyo, (2) Méndez y Romero. (3) Se realizaron corridas de elaboración del producto a escala de laboratorio, a fin de establecer las proporciones adecuadas del gel de Aloe frutado mezclando pulpa de fruta, azúcar y gel de Aloe, siendo la más aceptada la proporción 1:1:1. Se realizó la caracterización fisicoquímica y microbiológica de la materia prima y del producto terminado mediante las normas COVENIN y pruebas organolépticas a 10 jueces no entrenados para asegurar la aceptación del producto, de donde se obtuvo una bebida láctea fermentada con la adición de 50 % de gel de Aloe frutado con un pH de 4,51; una acidez titulable de 0,837 % de ácido láctico; 3,64 % de grasa y 12,92 % de sólidos no grasos. Respecto a la calidad microbiológica se encontraron levaduras escasas y ausencia de bacterias coliformes, con lo cual se cumple con los requisitos fisicoquímicos y microbiológicos exigidos por la normativa, permitiendo la obtención de un producto de calidad apto para el consumo humano a base de materias primas naturales.

RESUMEN Introducción: Las infecciones de sitio quirúrgico están asociadas con infecciones relacionadas a la asistencia sanitaria (IRAS), causadas por bacterias que ingresan a través de las incisiones efectuadas durante un procedimiento quirúrgico. Objetivo: Describir la frecuencia y características de las infecciones de sitio quirúrgico en las cirugías de urgencias en pacientes pediátricos hospitalizados en el Hospital General Pediátrico. Materiales y Métodos: Estudio observacional descriptivo, retrospectivo, de corte transversal. Población: Pacientes de 0 a 18 años sometidos a intervención quirúrgica abdominal de urgencia. Variables estudiadas: Edad, Sexo, Procedencia, Comorbilidad, reingreso hospitalario, tiempo trascurrido entre la intervención quirúrgica y la aparición de la infección en sitio quirúrgico. Datos obtenidos del análisis de fichas clínicas y la base de datos del HIS en el paquete estadístico SPSv23 (IBM SPSS, DEMO) utilizando estadística descriptiva. Resultados: Fueron incluidas 440 fichas de pacientes, la mediana de edad fue de 10 años, el 60,5% fueron del sexo masculino y el 71,4% procedían del Departamento Central. Se observó que el diagnóstico más frecuente fue peritonitis de origen apendicular 53,2%. El estado nutricional de la población en estudio fue normal en 93,2%, y fueron reingresos el 3% de los pacientes intervenidos. Presentaron infección de sitio quirúrgico el 4,8%, de los cuales 11/21 fueron absceso de pared. En cuanto al tiempo trascurrido entre la cirugía y la aparición de la infección la mediana fue de 14 días. Conclusión: La frecuencia de infección del sitio quirúrgico encontrada en este estudio fue del 4,8%. La patología quirúrgica con mayor porcentaje fue la peritonitis y el tipo de infección absceso de pared. La mayoría de los pacientes eran escolares con buen estado nutricional.

ABSTRACT Introduction: Surgical-site infections are associated with healthcare-associated infections (HAIs), caused by bacteria that enter through the incisions made during a surgical procedure. Objective: To describe the frequency and characteristics of surgical site infections in emergency surgeries in pediatric patients hospitalized at a Pediatric General Hospital. Materials and Methods: This was a descriptive, retrospective and cross-sectional observational study. Population: Patients aged 0 to 18 years undergoing emergency abdominal surgery. Variables studied: Age, Sex, Origin, Comorbidity, hospital readmission, time elapsed between the surgical intervention and the appearance of the surgical site infection. Data obtained from the analysis of clinical records and the electronic health record database in the SPSv23 statistical package (IBM SPSS, DEMO) using descriptive statistics. Results: 440 patient records were included, the median age was 10 years, 60.5% were male and 71.4% came from the Central Department. It was observed that the most frequent diagnosis was peritonitis of appendiceal origin 53.2%. The nutritional status of the study population was normal in 93.2%, and 3% of the operated patients were readmitted. 4.8% had surgical site infection, of which 11/21 were wall abscesses. Regarding the time elapsed between surgery and the appearance of the infection, the median was 14 days. Conclusion: The frequency of surgical-site infection found in this study was 4.8%. The surgical pathology with the highest percentage was peritonitis and the wall abscess type of infection. Most of the patients were schoolchildren with good nutritional status.

Abstract A previously healthy 16-year-old male with a ten-day history of proptosis and pain in the left upper eyelid and inflammatory signs of the left lower limb, without fever, was admitted to the Emergency Department. Computed tomography (CT) scan revealed an extensive intraorbital lesion and a multiloculated collection in the muscle planes of the thigh. The boy underwent surgical drainage and was started on empiric antibiotics. Methicillin-susceptible Staphylococcus aureus was isolated from blood and exudate cultures. Because the boy remained febrile, a chest CT scan was performed, which revealed bilateral cavitary lung lesions. He completed a long course of antibiotherapy. The study for potential immunodeficiency disorders was unremarkable. Most pediatric cases of community-associated Staphylococcus aureus bacteremia are associated with a localized source of infection. Diagnosis depends on isolation from blood and fluid aspirates. Treatment usually requires surgical drainage and intravenous antibiotherapy. Staphylococcus aureus bacteremia may be associated with multiple foci of infection, which should be recognized promptly.

Resumo Um adolescente do sexo masculino de 16 anos de idade, previamente saudável, foi admitido no Serviço de Urgência por proptose e dor na pálpebra superior esquerda e sinais inflamatórios no membro inferior esquerdo, sem febre, com dez dias de evolução. A tomografia computorizada (TC) revelou uma lesão expansiva intraorbitária e coleção multiloculada nos planos musculares da coxa. O rapaz foi submetido a drenagem cirúrgica e iniciou antibioterapia empírica. A hemocultura e cultura dos exsudados permitiram o isolamento de Staphylococcus aureus sensível à meticilina. Dado que o rapaz continuava febril, foi realizada TC torácica, que evidenciou lesões pulmonares cavitadas bilateralmente, tendo sido efetuado um esquema prolongado de antibioterapia. O estudo de potenciais imunodeficiências foi negativo. A maioria dos casos de bacteremia a Staphylococcus aureus na comunidade estão associados a focos infeciosos localizados. O diagnóstico requer isolamento no sangue ou exsudados. A abordagem implica drenagem cirúrgica e antibioterapia endovenosa. A bacteremia a Staphylococcus aureus pode associar-se a múltiplos focos de infeção, pelo que deve ser precocemente reconhecida.

Abstract Faced with the challenges posed by the need for fertilizers to maintain agricultural production, a biological process of atmospheric nitrogen fixation occurs naturally, which is carried out by a group of symbiotic bacteria that form a very close association with plants of the legume group, among which is the sweet clover (Melilotus spp.). From an ecological point of view, this plant has an essential function due to its good ability to associate with native nitrogen-fixing bacteria of the genus Sinorhizobium. A fundamental aspect is that this plant species can grow normally in alkaline soils, which doubles its importance since, on the one hand, it fixes nitrogen, and on the other hand, it can be incorporated as green manure. With this, the physicochemical properties of the soil are improved, and the levels of organic matter, which is in extremely poor condition in arid zone areas, are increased. Additionally, this species can withstand low temperatures and grow satisfactorily in winter. This paper presents a synthesis of the genus Melilotus and its symbiont Sinorhizobium meliloti and its importance as a potential natural soil improver.

Resumen Ante los retos por la necesidad de fertilizantes para mantener la producción agrícola, ocurre naturalmente un proceso biológico de fijación de nitrógeno atmosférico por parte de un grupo de bacterias simbióticas que forman una asociación muy estrecha con plantas del grupo de las leguminosas, entre las que se encuentran las alfalfillas o tréboles silvestres (Melilotus spp.). Desde el punto de vista ecológico esta planta tiene una función muy importante por la buena capacidad de asociarse a bacterias nativas del suelo fijadoras de nitrógeno del género Sinorhizobium. Un aspecto fundamental es que esta especie vegetal puede crecer normalmente en suelos alcalinos, lo que le convierte aún más como doble importante, ya que, por un lado, fija nitrógeno y por el otro puede incorporarse como abono verde. Con ello, se mejoran las propiedades físico-químicas del suelo y, se incrementan los niveles de materia orgánica, condición que es muy pobre en las áreas de zonas áridas. Adicionalmente, esta especie puede resistir bajas temperaturas y crecer satisfactoriamente en invierno. Este documento presenta una síntesis del género Melilotus y su simbionte Sinorhizobium meliloti, así como su importancia como posible mejorador natural del suelo.

Resumen La interacción entre SARS-CoV-2 e infecciones invasivas por bacterias capsuladas (IIBC) continúa bajo estudio. Objetivos: comparar la incidencia de IIBC antes y durante la pandemia por COVID-19, evaluar la incidencia de coinfección con COVID-19 y la letalidad. Estudio transversal de registros de un laboratorio centralizado de Microbiología, que asiste a una red de centros asistenciales con 713 camas de internación para adultos y pediátricos, expandida 20% durante la pandemia. Tres periodos evaluados: 1) Pre-pandemia: 1-Marzo-2019 al 29-Febrero-2020; 2) Primer año de Pandemia: 1-Marzo-2020 al 28-Febrero-2021; 3) Pandemia 2021: 1-Marzo-2021 al 31-Julio-2021. Análisis estadístico descriptivo: Se analizaron 56.502 muestras (96% hemocultivos) correspondientes a 27.224 pacientes. De estas, 54 muestras (de 54 pacientes) fueron positivas para bacterias capsuladas. La incidencia de IIBC fue 167,4, 32,6 y 50,4 por cada 100.000 muestras para los periodos 1, 2 y 3, respectivamente. Doce IIBC ocurrieron durante la pandemia: 10 Streptococcus pneumoniae y dos Haemophilus influenzae, siete de ellos corresponden a coinfección SARS-CoV-2/S. pneumoniae, con una incidencia de 5,68 por cada 10.000 internaciones por COVID 19 (0,056%). La letalidad de las IIBC fue de 31, 29 y 60% para los tres periodos, respectivamente, 3/7 coinfectados fallecieron (43%). La letalidad por enfermedad neumocócica invasiva (ENI), sin COVID fue de 32,5%. Se evidenció una reducción significativa de la incidencia de IIBC luego del comienzo de la pandemia, coincidente con la implementación de las medidas sanitarias de contención de la pandemia. La incidencia de coinfección de SARS-CoV-2/S. pneumoniae fue baja y presentó mayor letalidad que las ENI sin COVID-19.

Abstract Interaction between severe acute respiratory coronavirus 2 (SARS-CoV-2) and IIEB remains under investigation. Objective: to compare IIEB incidence before and during COVID-19 pandemic, and assess incidence of coinfection with COVID-19 and case fatality. A cross-sectional study was performed on data from a centralized microbiology laboratory serving a network of healthcare centers comprising 713 pediatric and adult inpatient beds, expanded by 20% during the pandemic. Three periods were evaluated: (1) pre-pandemic: March 1, 2019-February 29, 2020; (2) pandemic year 1: March 1, 2020-February 28, 2021; (3) pandemic year 2: March 1, 2021-July 31, 2021. Descriptive statistical analysis was performed. 56502 samples (96% blood cultures) from 27224 patients were analyzed. Of these, 54 samples (from 54 patients) were positive for encapsulated bacteria. IIEB incidence was: 167.4, 32.6, and 50.4 per 100000 samples for periods 1, 2, and 3, respectively. Twelve IIEB episodes occurred during the pandemic period: 10 Streptococcus pneumoniae, and 2 Haemophilus influenzae, of which 7 were SARS-CoV-2/S. pneumoniae coinfections, with an incidence of 5.68 per 10000 COVID-19-related hospitalizations (0.056%). IIEB case fatality was 31%, 29%, and 60% for each period, respectively, 3/7 patients with coinfection died (43%). Case fatality for invasive pneumococcal disease (IPD) in patients without COVID-19, was 32.5%. Significant reduction in IIEB incidence was observed during the pandemic, coinciding with implementation of containment measures. The incidence of SARS-CoV-2/S. pneumoniae coinfection was low, with higher case fatality than IPD patients without COVID-19.

Resumen El objetivo de este estudio fue comparar el desempeño de dos sistemas MALDI-TOF MS en la identificación de bacterias anaerobias estrictas de interés clínico. La secuenciación del gen 16S ARNr fue el método de referencia utilizado cuando se observaron discrepancias o inconsistencias entre plataformas. Se recuperaron 333 aislados de muestras clínicas de diferentes centros de la Ciudad Autónoma de Buenos Aires entre 2016 y 2021. Los aislados se identificaron por duplicado mediante dos sistemas MALDI-TOF MS: el BD Bruker Biotyper (Bruker Daltonics, Bremen, Alemania) y el Vitek MS (bioMèrieux, Marcy-l'Etoile, Francia). A través del sistema Vitek MS, los mismos fueron identificados a nivel de especie o complejo de especies en un 65,5% (n: 218) y de género en un 71,2% (n: 237), mientras que no se identificaron en un 29,4% (n: 98) y fue incorrecta en el 5,1% (n: 17). Mediante el sistema Bruker Biotyper, dichos valores fueron del 85,3% (n: 284), del 89,7% (n: 299), del 14,1% (n: 47) y del 0,6% (n: 2), respectivamente. La diferencia entre ambos métodos fue estadísticamente significativa (p<0,0001). En conclusión, los sistemas MALDI-TOF MS aceleran la identificación microbiana. Son especialmente útiles para los microorganismos de crecimiento lento, como las bacterias anaerobias, que son difíciles de identificar con los métodos tradicionales. El sistema Bruker demostró ser más preciso que el Vitek MS. Para que estos métodos sean realmente efectivos es fundamental actualizar las bases de datos de ambos sistemas e incrementar el número de espectros de referencia dentro de las plataformas.

Abstract The aim of this study was to compare the performance of two MALDI-TOF MS systems in the identification of clinically relevant strict anaerobic bacteria. The 16S rRNA gene sequencing was the gold standard method when discrepancies or inconsistencies were observed between platforms. A total of 333 isolates were recovered from clinical samples of different centers in Buenos Aires City between 2016 and 2021. The isolates were identified in duplicate using two MALDI-TOF MS systems, BD Bruker Biotyper (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMèrieux, Marcy-l’Etoile, France). Using the Vitek MS system, the identification of anaerobic isolates yielded the following percentages: 65.5% (n: 218) at the species or species-complex level, 71.2% (n: 237) at the genus level, 29.4% (n: 98) with no identification and 5.1% (n: 17) with misidentification. Using the Bruker Biotyper system, the identification rates were as follows: 85.3% (n: 284) at the species or species-complex level, 89.7% (n: 299) at the genus level, 14.1% (n: 47) with no identification and 0.6% (n: 2) with misidentification. Differences in the performance of both methods were statistically significant (p-values <0.0001). In conclusion, MALDI-TOF MS systems speed up microbial identification and are particularly effective for slow-growing microorganisms, such as anaerobic bacteria, which are difficult to identify by traditional methods. In this study, the Bruker system showed greater accuracy than the Vitek system. In order to be truly effective, it is essential to update the databases of both systems by increasing the number of each main spectrum profile within the platforms.

Although South Africa is known as one of the most biodiverse countries in the world, based on its unique plants and animals, microorganisms have received much less attention. Microorganisms in general and actinobacteria in particular are an underexplored source of new medicines. Recent studies have demonstrated the presence of diverse cultivable actinobacteria from various biomes. However, investigations of the natural product diversity associated with these microorganisms are lacking. We hereby present a review of natural products isolated from South African actinobacteria together with their biological activities. Many of these natural products are structurally novel and include compounds belonging to the following classes: anthraquinones, isoflavonoids, ketolides, macrolides, macrolactams, tripeptides and depsipeptides. They show a wide range of biological activities including antibacterial, antifungal, cytotoxic and antitumour activities. SIGNIFICANCE: • This review highlights the importance of actinobacteria in the discovery of new medicines and summarises the state-of-the-art on their research in South Africa. • We reveal a gap in the exploitation of this resource and emphasise the opportunities for multidisciplinary research.

ABSTRACT Cotton (Gossypium hirsutum L.) is economically important in Xinjiang, China, for many years; Verticillium wilt, arid climate, and soil salinization reduce cotton production, which has inhibited development of the cotton economy. Thus, creating a microbial agent specifically for cotton to resisting environmental stress is crucial. In this study, water dispersible granules strains (Bacillus tequilensis C-9 and B. sphingosporium A1) were screened for antagonistic bacteria of Verticillium dahliae from the rhizosphere soil of Ferula sinkiangensis K.M. Shen, and screened for carrier and auxiliary that could enhance the survival of strains A1+C-9. To test the efficacy and practicality of the water dispersible granules, their growth-promoting effect was examined. Meanwhile, bursts of reactive oxygen species and changes in the physiological indicators related to cotton growth were detected after the application of these granules to cotton that had been subjected to biotic and abiotic stresses to study the ability of the water dispersible granules to induce immunity in cotton. It was found that the treated group could increase the above-ground and below-ground fresh weight of cotton by 20.06% and 22.71% relative to the control group, and the biocontrol effect on cotton was increased by 46.55%. In salt and drought stress, catalase activity could be increased by 14.61% and 15.52%, respectively, relative to the control group. Comprehensive analyses showed that the application of water dispersible granules that contained A1+C-9 helped the cotton to grow and develop, inhibited V. dahliae from infecting cotton plants, reduced the damage from drought and salt stress, and increased the resilience of cotton to stress.

INTRODUCTION: Contaminated disinfectants have been occasional vehicles of healthcare associated infections. AIMS AND OBJECTIVES: To determine the presence and level of bacterial contamination of disinfectants used to decontaminate suction devices and to assess the extent to which students comply with infection control practices. DESIGN: A two-part cross-sectional descriptive study consisting of microbiological testing of disinfectants and a questionnaire-based observation of students. METHODS: Unannounced observation of students disinfecting suction devices were recorded using a questionnaire. The process involved collecting a prepared disinfectant from a storage bin using a kitchen measuring jug. Specimens of disinfectants and swabs of jugs were collected for aerobic culture. Data pertaining to compliance with infection control practices was gathered. RESULTS: Only 33.6% of the students were observed unannounced. An overwhelming majority (84.9%) of students disinfected suction devices; 52% cleaned and disinfected the external surface of suction hoses and the spittoon bowl; 18.6% allowed the disinfectant to remain in the system long enough, and 14% advised their patients not to close their lips around the suction device. The majority of disinfectant samples (56.3%) as well jugs (55.6%) were contaminated with bacteria. CONCLUSION: Bacterial contamination of disinfectants was common in addition to poor compliance with infection control practices.

ABSTRACT Vermiculite mining residues, although of low solubility, contain nutrients such as calcium, magnesium, and potassium at concentrations that allow their agricultural use. Beneficial bacteria can increase the solubility of this waste and its efficiency. The objective of the present study was to evaluate the influence of bio-inoculation of vermiculite residue, associated with cattle manure, on the release of nutrients and initial growth of maize. A completely randomized design was performed in a greenhouse with seven treatments and four replications. The treatments were: T1 - soil without fertilization; T2 - soil fertilized with soluble sources of nutrients (conventional fertilization); T3 - application of vermiculite residue (VR); T4 - VR enriched with cattle manure (CM); T5 - VR + CM with Bacillus subtilis; T6 - VR + CM + B. amyloliquefaciens, and T7 - VR + CM +B. subtilis + B. amyloliquefaciens). Regardless of the use of cattle manure or beneficial microorganisms, vermiculite mining waste increased the availability of Ca and K in the soil, but was not able to match the soluble sources of nutrients. Mining waste associated with cattle manure and beneficial microorganisms (B. subtilis and B. amyloliquefaciens) increased microbial activity and enhanced the release of available calcium for maize. VR increased the growth and the dry mass production of maize compared to the non-fertilized soil, but was consistently inferior to conventional fertilizer.

RESUMO Os resíduos da mineração de vermiculita, embora de baixa solubilidade, contêm nutrientes como cálcio, magnésio e potássio em concentrações que permitem seu uso agrícola. Bactérias benéficas podem aumentar a solubilidade deste resíduo e sua eficiência. Objetivou-se avaliar a influência da bioinoculação do resíduo de vermiculita, associado ao esterco bovino, na liberação de nutrientes e no crescimento inicial do milho. Foi realizado delineamento inteiramente casualizado em casa de vegetação com sete tratamentos e quatro repetições. Os tratamentos foram: T1 - solo sem adubação; T2 - solo adubado com fontes solúveis de nutrientes (fertilização convencional); T3 - aplicação de resíduo de vermiculita (VR); T4 - VR enriquecido com esterco bovino (CM); T5 -VR+CM com Bacillus subtilis; T6 - VR + CM + B. amyloliquefaciens e T7 - VR + CM + B. subtilis + B. amyloliquefaciens). O VR aumentou a disponibilidade de Ca e K no solo, porém seu desempenho foi inferior às fontes solúveis. Independentemente da utilização de esterco bovino ou de microrganismos benéficos, os resíduos da mineração de vermiculita aumentaram a disponibilidade de Ca e K no solo, mas não foram capazes de igualar as fontes solúveis de nutrientes. Os resíduos de mineração associados ao esterco bovino e aos microrganismos benéficos (B. subtilis e B. amyloliquefaciens) aumentaram a atividade microbiana e aumentaram a liberação de cálcio disponível para o milho. Os resíduos da mineração de vermiculita aumentaram o crescimento e a produção de massa seca do milho em comparação ao solo não fertilizado, mas foram consistentemente inferiores ao fertilizante convencional.

ABSTRACT The symbiosis of common beans with nitrogen-fixing bacteria provides an efficient approach to sustainable and economical food production. Therefore, this study aimed to evaluate the application of cost-effective nitrogen management strategies in organic common bean cultivation, including the application of poultry manure and organic liquid fertilizer, seed and co-inoculation with diazotrophic bacteria (Azospirillum brasilense and/or Rhizobium tropici), and supplementary Rhizobium tropici inoculation. The study spanned three years in a well-established organic cultivation field (2018) and an initial organic cultivation area (2019 and 2020) in Brazil. It was arranged in a randomized blocks design in a 2 × 5 (2018) and 2 × 6 (2019 and 2020) factorial scheme, with four replicates. The most profitable strategy involves seed inoculation with Azospirillum brasilense and additional inoculation with Rhizobium tropici at stage V4-5 (fifth trifoliate leaf fully expanded), while the most costly strategy was the application of poultry manure at the V3 stage (first trifoliate leaf fully expanded). Thus, the use of diazotrophic bacteria for seed inoculation and co-inoculation (Azospirillum brasilense and/or Rhizobium tropici) ensured financial returns and system profitability in common bean cultivation.

RESUMO A simbiose do feijão comum com bactérias fixadoras de nitrogênio proporciona uma abordagem eficiente para a produção de alimentos sustentável e econômica. Portanto, este estudo teve como objetivo avaliar a aplicação de estratégias custo-efetivas de manejo de nitrogênio no cultivo orgânico do feijão comum, incluindo a aplicação de esterco de aves e fertilizante orgânico líquido, inoculação de sementes e coinoculação com bactérias diazotróficas (Azospirillum brasilense e/ou Rhizobium tropici), e inoculação suplementar com Rhizobium tropici. O estudo durou três anos em um campo de cultivo orgânico bem estabelecido (2018) e uma área inicial de cultivo orgânico (2019 e 2020) no Brasil. O delineamento foi em blocos casualizados em esquema fatorial 2 × 5 (2018) e 2 × 6 (2019 e 2020), com quatro repetições. A estratégia mais lucrativa envolve a inoculação de sementes com Azospirillum brasilense e inoculação adicional com Rhizobium tropici no estádio V4-5 (quinta folha trifoliada totalmente expandida), enquanto a estratégia mais cara foi a aplicação de esterco de aves no estádio V3 (primeira folha trifoliada totalmente expandida). Assim, o uso de bactérias diazotróficas para inoculação e coinoculação de sementes (Azospirillum brasilense e/ou Rhizobium tropici) garantiu retorno financeiro e rentabilidade do sistema no cultivo do feijão comum.