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1. Salmonella Gallinarum strains isolated from a southern Brazil fowl typhoid outbreak were subjected to phenotypic and genotypic analyses to identify genetic elements that could improve prevention and control strategies.2. Whole-genome sequencing revealed the presence of the aac(6')-Iaa gene, conferring aminoglycoside resistance, along with novel chromosomal point mutations, including the first detection of parE p.S451F in Salmonella Gallinarum.3. Additionally, IncFII(S) plasmid replicons, Salmonella pathogenicity islands and 105 virulence genes associated with cell adhesion, invasion and antimicrobial peptide resistance were identified.4. These findings shed light on the molecular mechanisms of fowl typhoid and provide crucial insights into emerging antimicrobial resistance and virulence factors.
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Tea (Camellia sinensis), a perennial evergreen shrub, is one of the most important cash crops in China. Tea leaves with symptoms of wilt disease was observed in Fengqing County, Lincang City, Yunnan Province, China. Large irregular jujube-red necrotic spots appeared on the leaves of tea plants, and the lesions with grayish white edge were accompanied by a certain degree of shrinkage. In the tea garden planting base, the natural disease incidence reached 40%-50 %, which significantly affects the yield of tea. One putative pathogen was isolated from three symptomatic tea plant leaves and was identified as Discosia brasiliensis using morphology and molecular phylogeny of multi-loci (ITS, LSU, tub, rpb2) sequence data. Using D. brasiliensis strains for artificial inoculation assay on the tea plant leaves, leaf atrophy symptom in leaves which is similar to those observed in the tea planting base, and the putative pathogen was re-isolated to fulfill Koch's postulates. This is the first report of wilt disease caused by Discosia brasiliensis in China.
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Camellia sinensis , Filogenia , Enfermedades de las Plantas , Hojas de la Planta , Enfermedades de las Plantas/microbiología , China , Hojas de la Planta/microbiología , Camellia sinensis/microbiología , Ascomicetos/genética , Ascomicetos/aislamiento & purificación , Ascomicetos/clasificación , Ascomicetos/patogenicidad , Análisis de Secuencia de ADN , ADN de Hongos/genéticaRESUMEN
Castilleja tenuiflora is a native perennial plant used in traditional Mexican medicine. In June 2022, leaf blight symptoms were observed in a wild population of C. tenuiflora plants. Disease incidence was 80% and disease intensity reached up to 5% of the leaf area. Currently, there are no reports of pathogens causing leaf blight in this plant; therefore, this work aimed to identify the fungi responsible for the disease. The fungi recovered from the diseased tissue were characterized by means of pathogenicity tests and cultural, morphological, and molecular characterization. The information obtained revealed that Alternaria alternata and Alternaria gossypina are the pathogens responsible for the disease. This is the first report implicating species of Alternaria in causing leaf blight of C. tenuiflora in Mexico, as well as the first report of Alternaria gossypina also in Mexico. These pathogens may threaten the in situ conservation of native C. tenuiflora populations and limit their in vitro propagation. Future research lines should focus on determining the effect of these pathogens on metabolite production.
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In this pioneering in silico study in Peru, we aimed to analyze Escherichia coli (E. coli) genomes for antimicrobial resistance genes (ARGs) diversity and virulence and for its mobilome. For this purpose, 469 assemblies from human, domestic, and wild animal hosts were investigated. Of these genomes, three were E. coli strains (pv05, pv06, and sf25) isolated from chickens in our previous study, characterized for antimicrobial susceptibility profile, and sequenced in this study. Three other genomes were included in our repertoire for having rare cgMLSTs. The phenotypic analysis for antimicrobial resistance revealed that pv05, pv06, and sf25 strains presented multidrug resistance to antibiotics belonging to at least three classes. Our in silico analysis indicated that many Peruvian genomes included resistance genes, mainly to the aminoglycoside class, ESBL-producing E. coli, sulfonamides, and tetracyclines. In addition, through Multi-locus Sequence Typing, we found more than 180 different STs, with ST10 being the most prevalent among the genomes. Pan-genome mapping revealed that, with new lineages, the repertoire of accessory genes in E. coli increased, especially genes related to resistance and persistence, which may be carried by plasmids. The results also demonstrated several genes related to adhesion, virulence, and pathogenesis, especially genes belonging to the high pathogenicity island (HPI) from Yersinia pestis, with a prevalence of 42.2% among the genomes. The complexity of the genetic profiles of resistance and virulence in our study highlights the adaptability of the pathogen to different environments and hosts. Therefore, our in silico analysis through genome sequencing enables tracking the epidemiology of E. coli from Peru and the future development of strategies to mitigate its survival.
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In Chile, Piscirickettsia salmonis contains two genetically isolated genogroups, LF-89 and EM-90. However, the impact of a potential co-infection with these two variants on Salmonid Rickettsial Septicemia (SRS) in Atlantic salmon (Salmo salar) remains largely unexplored. In our study, we evaluated the effect of P. salmonis LF-89-like and EM-90-like co-infection on post-smolt Atlantic salmon after an intraperitoneal challenge to compare changes in disease dynamics and host immune response. Co-infected fish had a significantly lower survival rate (24.1%) at 21 days post-challenge (dpc), compared with EM-90-like single-infected fish (40.3%). In contrast, all the LF-89-like single-infected fish survived. In addition, co-infected fish presented a higher presence of clinical lesions than any of the single-infected fish. The gene expression of salmon immune-related biomarkers evaluated in the head kidney, spleen, and liver showed that the EM-90-like isolate and the co-infection induced the up-regulation of cytokines (e.g., il-1ß, ifnγ, il8, il10), antimicrobial peptides (hepdicin) and pattern recognition receptors (PRRs), such as TLR5s. Furthermore, in serum samples from EM-90-like and co-infected fish, an increase in the total IgM level was observed. Interestingly, specific IgM against P. salmonis showed greater detection of EM-90-like antigens in LF-89-like infected fish serum (cross-reaction). These data provide evidence that P. salmonis LF-89-like and EM-90-like interactions can modulate SRS disease dynamics in Atlantic salmon, causing a synergistic effect that increases the severity of the disease and the mortality rate of the fish. Overall, this study contributes to achieving a better understanding of P. salmonis population dynamics.
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Coinfección , Enfermedades de los Peces , Piscirickettsia , Infecciones por Piscirickettsiaceae , Salmo salar , Animales , Piscirickettsia/fisiología , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/inmunología , Infecciones por Piscirickettsiaceae/veterinaria , Infecciones por Piscirickettsiaceae/microbiología , Coinfección/veterinaria , Coinfección/microbiología , Coinfección/inmunología , Chile , Sepsis/veterinaria , Sepsis/microbiología , Sepsis/inmunologíaRESUMEN
Clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 virus was detected in the South American sea lions found dead in Santa Catarina, Brazil, in October 2023. Whole genome sequencing and comparative phylogenetic analysis were conducted to investigate the origin, genetic diversity, and zoonotic potentials of the H5N1 viruses. The H5N1 viruses belonged to the genotype B3.2 of clade 2.3.4.4b H5N1 virus, which was identified in North America and disseminated to South America. They have acquired new amino acid substitutions related to mammalian host affinity. Our study provides insights into the genetic landscape of HPAI H5N1 viruses in Brazil, highlighting the continuous evolutionary processes contributing to their possible adaptation to mammalian hosts.
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Subtipo H5N1 del Virus de la Influenza A , Filogenia , Leones Marinos , Secuenciación Completa del Genoma , Animales , Leones Marinos/virología , Brasil , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/clasificación , Infecciones por Orthomyxoviridae/veterinaria , Infecciones por Orthomyxoviridae/virología , Genoma Viral , Genotipo , Variación GenéticaRESUMEN
The rubber tree (Hevea brasiliensis) is one of the major domesticated crops planted commercially for the production of natural rubber (NR) worldwide. In recent years, rubber trees in the Southern states of India and other rubber-producing countries have experienced a severe leaf spot disease, characterized by the appearance of several brown circular spots in the initial stage, which later spread all over the lamina of fully matured leaves, leading to yellowing and defoliation. The causal organism of this Circular Leaf Spot (CLS) disease has not been conclusively identified in any previous studies. In this study, we collected infected leaf samples from various locations in the South Indian states. We aimed to identify the actual fungal pathogen that causes the CLS disease on rubber trees. Based on the morphological and molecular analysis of the most frequently isolated fungi from infected leaf samples were identified as Colletotrichum siamense and Colletotrichum fructicola. Pathogenicity tests also confirmed the involvement of isolated Colletotrichum spp. in the development of CLS disease. These findings provide valuable insights into understanding the CLS disease and its impact on rubber cultivation. To our knowledge, it is the first report of C. siamense and C. fructicola associated with CLS disease of rubber trees in India.
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Colletotrichum , Hevea , Enfermedades de las Plantas , Hojas de la Planta , Hevea/microbiología , Colletotrichum/genética , Colletotrichum/aislamiento & purificación , Colletotrichum/clasificación , Enfermedades de las Plantas/microbiología , India , Hojas de la Planta/microbiología , ADN de Hongos/genética , Filogenia , Análisis de Secuencia de ADN , Datos de Secuencia MolecularRESUMEN
Granuloviruses (GVs) Betabaculovirus associated with the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), especially those of the type I, have scarcely been studied. These GVs might be an effective alternative for the biocontrol of this insect. In this study, the native GVs SfGV-CH13 and SfGV-CH28 were isolated from FAW larvae and characterized for morphology, molecular traits, and insecticidal activity. The elapsed time between symptomatic infection of larvae and stop feeding as well as the weight of larvae before death or prior to pupation were also evaluated. Both GVs had ovoid shape and a length of 0.4 µm. They had the same DNA restriction profiles and their genome sizes were about 126 kb. The symptomatic infection with the tested GVs mainly caused flaccidity of larva body and discoloration of integument. The integument lysis was only observed in 8% of infected larvae. Infected larvae gradually stopped feeding. Overall, these symptoms are characteristic of infections caused by type I GVs, which are known as monoorganotropic or slow-killing GVs. The median lethal dose (LD50) values for SfGV-CH13 and SfGV-CH28 isolates were 5.4 × 102 and 1.1 × 103 OBs/larva, respectively. The median lethal time (LT50) ranged from 17 to 24 days. LT50 values decreased as the viral dose was increased. The elapsed time from symptomatic infection until pupation and body weight of larvae (third instar) were higher with SfGV-CH28 than SfGV-CH13. Both granulovirus isolates were able to kill the FAW larvae from the 12th day.
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Granulovirus , Larva , Spodoptera , Animales , Spodoptera/virología , Granulovirus/genética , Larva/virologíaRESUMEN
Uropathogenic Escherichia coli (UPEC) is the main cause of urinary tract infections (UTIs) and carries virulence and resistance factors often found in mobilizable genetic elements, such as plasmids or pathogenicity islands (PAIs). UPEC is part of the extraintestinal pathogenic E. coli (ExPEC), but hybrid strains possessing both diarrheagenic E. coli (DEC) and ExPEC traits, termed "hypervirulent", present a significant health threat. This study assessed the prevalence of UPEC PAIs, ExPEC sequence types (ST), DEC genes, carbapenemase and extended-spectrum ß-lactamase (ESBL) phenotypes, resistance genotypes, and plasmids in 40 clinical isolates of UPEC. Results showed that 72.5% of isolates had PAIs, mainly PAI IV536 (53%). ESBL phenotypes were found in 65% of ß-lactam-resistant isolates, with 100% of carbapenem-resistant isolates producing carbapenemase. The predominant ESBL gene was blaCTX-M-2 (60%), and the most common resistance gene in fluoroquinolone and aminoglycoside-resistant isolates was aac(6')Ib (93%). Plasmids were present in 57% of isolates, and 70% belonged to the ST131 clonal group. Molecular markers for DEC pathotypes were detected in 20 isolates, with 60% classified as hybrid pathotypes. These findings indicate significant pathogenic potential and the presence of hybrid pathotypes in E. coli UTI clinical isolates in the Mexican population.
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Entomopathogenic fungi have been considered potential biological control agents against the fall armyworm Spodoptera frugiperda (J. E. Smith), the world's most important pest of maize. In this study, we evaluated the natural infection, molecular characteristics, and biological activity of Metarhizium rileyi (Farlow) isolated from S. frugiperda larvae of this insect, collected from maize crops in five Mexican locations. Natural infection ranged from 23% to 90% across all locations analyzed. Twenty-four isolates were evaluated on S. frugiperda second instars at a concentration of 1.0 × 108 conidia/mL, causing 70% to 98.7% mortality and 60.5% to 98.7% sporulation. Isolates T9-21, Z30-21, PP48-21, and L8-22 were selected to determine their phylogenetic relationships by ß-tubulin gene analysis and to compare median lethal concentration (CL50), median lethal time (LT50), and larval survival. These isolates were grouped into three clades. The T9-21, PP48-21, and J10-22 isolates were closely related (clade A), but phylogenetically distant from Z30-21 (clade B) and L8-22 (clade C) isolates. These genetic differences were not always reflected in their pathogenicity characteristics since no differences were observed among the LC50 values. Furthermore, isolates T9-21, J10-22, and L8-22 were the fastest to kill S. frugiperda larvae, causing lower survival rates. We conclude that native M. rileyi isolates represent an important alternative for the biocontrol of S. frugiperda.
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Pathobionts have been implicated in various chronic diseases, including Crohn's disease (CD), a multifactorial chronic inflammatory condition that primarily affects the gastrointestinal tract, causing inflammation and damage to the digestive system. While the exact cause of CD remains unclear, adherent-invasive Escherichia coli (AIEC) strains have emerged as key contributors to its pathogenesis. AIEC are characterized by their ability to adhere to and invade intestinal epithelial cells and survive and replicate inside macrophages. However, the mechanisms underlying the virulence and persistence of AIEC within their host remain the subject of intensive research. Toxin-antitoxin systems (TAs) play a potential role in AIEC pathogenesis and may be therapeutic targets. These systems generally consist of two components: a toxin harmful to the cell and an antitoxin that neutralizes the toxin's effects. They contribute to bacterial survival in adverse conditions and regulate bacterial growth and behavior, affecting various cellular processes in bacterial pathogens. This review focuses on the current information available to determine the roles of TAs in the pathogenicity of AIEC. Their contribution to the AIEC stress response, biofilm formation, phage inhibition, the maintenance of mobile genetic elements, and host lifestyles is discussed.
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Chayote (Sechium edule) is a crop of great economic and pharmaceutical importance in Mexico. Chayote is affected by Phytophthora capsici, which causes plant wilt and fruit rot. Three isolates of P. capsici (A1-C, A2-H, and A3-O) were obtained from three producing areas in Veracruz, Mexico. Morphometric characteristics of sporangia and the colony pattern on three different media were described. They were molecularly identified by amplification of the internal transcribed spacer region (ITS) and the partial sequence of cytochrome c oxidase subunit 1 (COI), sequences that were phylogenetically analyzed. The mating type, pathogenicity in S. edule fruits, and sensitivity to metalaxyl were determined. Isolate A1-C presented the largest sporangium; all sporangia were papillated, with different morphologies and pedicel lengths. All isolates showed different colony patterns: chrysanthemum (A1-C), stellate (A2-H), and petaloid (A3-O). The topology of the phylogenetic tree was similar for the ITS region and COI gene, the sequences of the three isolates clustered with sequences of the genus Phytophthora classified in group 2b, corroborating their identity as P. capsici. The mating type of isolates A1-C and A3-O was A2 and of isolate A2-H was A1. The pathogenicity test indicated that isolate A1-C was the most virulent and with intermediate sensitivity to metalaxyl. This work suggests that P. capsici isolates from various production areas in Mexico may exhibit morphological and virulence variability.
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Anthracnose caused by Colletotrichum is the most severe and widely occurring cashew disease in Brazil. Colletotrichum species are commonly found as pathogens, endophytes and occasionally as saprophytes in a wide range of hosts. The endophytic species associated with cashew trees are poorly studied. In this study, we report the Colletotrichum endophytic species associated with cashew trees in two locations in the state of Pernambuco, their prevalence in different plant organs (leaves, veins, branches and inflorescences), and compare the species in terms of pathogenicity and aggressiveness using different inoculation methods (wounded × unwounded). Six species of Colletotrichum were identified according to multilocus phylogenetic analyses, including Colletotrichum asianum, Colletotrichum chrysophilum, Colletotrichum karsti, Colletotrichum siamense, Colletotrichum theobromicola, and Colletotrichum tropicale. There were differences in the percentage of isolation in relation to the prevalence of colonized tissues and collection locations. C. tropicale was the prevalent species in both geographic areas and plant tissues collected, with no pattern of distribution of species between areas and plant tissues. All isolates were pathogenic in injured tissues of cashew plants. The best method to test the pathogenicity of Colletotrichum species was utilizing the combination of leaves + presence of wounds + conidial suspension, as it better represents the natural infection process. C. siamense was the most aggressive species.
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Anacardium , Colletotrichum , Endófitos , Filogenia , Enfermedades de las Plantas , Colletotrichum/genética , Colletotrichum/clasificación , Colletotrichum/aislamiento & purificación , Brasil , Anacardium/microbiología , Endófitos/clasificación , Endófitos/genética , Endófitos/aislamiento & purificación , Enfermedades de las Plantas/microbiología , ADN de Hongos/genética , Tipificación de Secuencias MultilocusRESUMEN
Species in the Melastomataceae (Myrtales) include trees and woody shrubs that are amongst the most common hosts of Chrysoporthe and related fungi. These fungi cause stem cankers, branch death and in extreme cases, kill their hosts. Chrysoporthe-like fungi were observed on Miconia spp. and Rhynchanthera grandiflora (Melastomataceae) plants during tree disease surveys in south-eastern Brazil including the states of Minas Gerais and Rio de Janeiro. The aims of this study were to isolate and identify the fungi utilising morphological characteristics and phylogenetic analyses. This led to the identification of a new species of Chrysoporthe described here as Chrysoporthe brasilensis sp.nov. Inoculations were conducted on R. grandiflora and M. theaezans, showing that C. brasiliensis is an aggressive pathogen. This study adds to a growing number of reports of new and pathogenic species of Chrysoporthe that potentially threaten native Myrtales globally, including important trees such as Eucalyptus, both in natural ecosystems and in planted forests.
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Melastomataceae , Filogenia , Enfermedades de las Plantas , Brasil , Melastomataceae/microbiología , Enfermedades de las Plantas/microbiología , ADN de Hongos/genética , Ascomicetos/clasificación , Ascomicetos/genética , Ascomicetos/aislamiento & purificación , ADN Ribosómico/genética , Análisis de Secuencia de ADN , ADN Espaciador Ribosómico/genética , ADN Espaciador Ribosómico/química , Análisis por ConglomeradosRESUMEN
AIMS: Pyometra and cystitis caused by Escherichia coli are common diseases identified in canine or feline females. The origin of pyometra infection remains uncertain, and effective prevention strategies for this disease are still unknown. This study aimed to provide a phenotypic characterization, including antimicrobial resistance and virulence profiles, of endometrial pathogenic (EnPEC) and uropathogenic (UPEC) E. coli strains isolated simultaneously from the same animal. METHODS AND RESULTS: Sixteen E. coli strains, from eight different animals, were analyzed in this study. The antimicrobial susceptibility profile of EnPEC and UPEC strains was determined using the disc diffusion method, which showed a similar susceptibility profile among strains (EnPEC and UPEC) from the same animal. The virulence profile of the strains was assessed through biofilm formation, as well as serum resistance abilities. EnPEC and UPEC strains from the same animal exhibited slight variations in their virulence and antimicrobial resistance capabilities. Overall, most of the strain pairs showed a high similarity in their ability to establish biofilms and survive in serum complement activity. CONCLUSIONS: Overall, strains of E. coli isolated from both pyometra and cystitis in the same animal, despite presenting distinct clinical diseases, exhibit a wide phenotypic similarity, suggesting a common origin for the strains.
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Biopelículas , Enfermedades de los Gatos , Cistitis , Infecciones por Escherichia coli , Escherichia coli , Pruebas de Sensibilidad Microbiana , Fenotipo , Piómetra , Animales , Cistitis/microbiología , Cistitis/veterinaria , Piómetra/microbiología , Piómetra/veterinaria , Femenino , Gatos , Perros , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli/aislamiento & purificación , Escherichia coli/patogenicidad , Enfermedades de los Gatos/microbiología , Biopelículas/crecimiento & desarrollo , Virulencia , Antibacterianos/farmacología , Enfermedades de los Perros/microbiología , Escherichia coli Uropatógena/aislamiento & purificación , Escherichia coli Uropatógena/patogenicidad , Farmacorresistencia BacterianaRESUMEN
During the SARS-CoV-2 pandemic angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) were constantly under the scientific spotlight, but most studies evaluated ACE2 and TMPRSS2 expression levels in patients infected by SARS-CoV-2. Thus, this study aimed to evaluate the expression levels of both proteins before, during, and after-infection. For that, nasopharyngeal samples from 26 patients were used to measure ACE2/TMPRSS2 ex-pression via qPCR. Symptomatic patients presented lower ACE2 expression levels before and after the infection than those in asymptomatic patients; however, these levels increased during SARS-CoV-2 infection. In addition, symptomatic patients presented higher expression levels of TMPRSS2 pre-infection, which decreased in the following periods. In summary, ACE2 and TMPRSS2 expression levels are potential risk factors for the development of symptomatic COVID-19, and the presence of SARS-CoV-2 potentially modulates those levels.
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Enzima Convertidora de Angiotensina 2 , COVID-19 , Serina Endopeptidasas , Humanos , Enzima Convertidora de Angiotensina 2/genética , SARS-CoV-2 , Serina Endopeptidasas/genéticaRESUMEN
Swarming motility is a type of movement used by pathogenic flagellated bacteria as virulence factor to colonize surfaces and cause damage to the host. Vibrio parahaemolyticus is a pathogenic flagellated bacterium that increases its virulence by switching from swimmer to swarming cells. The hosts of pathogenic V. parahaemolyticus include farmed shrimp. Therefore, methods to detect and quantify this movement are important to control shrimp diseases caused by pathogenic V. parahaemolyticus strains. We developed an optimized swarming motility assay by identifying the most optimal type of agar, and drying time of the culture medium, agar concentration and volume of the bacterial culture to achieve the fastest swarming motility during the migration of V. parahaemolyticus on Petri dishes during a 24-hour incubation period. The method includes data analysis that could be used as a tool to identify potential anti-virulence products by comparing the slopes of the linearized diameters of the swarming halos of bacteria treated with the products, as they migrate on Petri dishes over a 24-hour incubation period. Here we report:â¢A simple method for detection and quantification of swarming motility halos of V. parahaemolyticus bacteria.â¢A method that could be used as a tool to identify potential anti-virulence products.
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This study aimed to evaluate the use of palm kernel meal (PKM) in the traditional solid-state fermentation system to improve the production and quality of Cordyceps javanica conidia. The impact of PKM was determined by measuring conidia yield, viability, hydrophobicity, shelf life, and conidia pathogenicity against Diaphorina citri adults. By supplementing rice grains with 5% palm kernel meal increased the conidial yield by up to 40%, without compromising conidia viability and hydrophobicity. In addition, conidia caused higher levels of mortality by mycosis against D. citri adults (90%), relative to conidia harvested from rice (52%). The conidia recovered from rice/palm kernel meal mixtures also retained viability greater than 90% after storage for 10 months at 4 °C, while the conidia produced on rice reached 80%. Thus, conidia produced in the presence of palm kernel meal can be consumed immediately or in the medium term. Some process advantages of the palm kernel meal as co-substrate in the traditional production system of C. javanica are also mentioned. These results are attractive for improving the mycoinsecticide production process, with excellent cost-benefit and minimal changes in infrastructure and process.
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Cordyceps , Hemípteros , Animales , Esporas FúngicasRESUMEN
Mastitis caused by Staphylococcus aureus is a worldwide problem in dairy farms, in part because of the pathogenicity of the bacteria, biofilm formation, and mechanisms of antimicrobial resistance that make the disease difficult to diagnose and treat, which is typically done with the use of beta-lactam antibiotics. The aim of the present study was to determine the virulence and resistance factors of S. aureus isolates from subclinical mastitis, blaZ + /mecA - /mecC - , resistant and sensitive to oxacillin. All isolates were classified as CC97 by MLST analysis, a clonal complex well adapted to the mammary gland and although STAU23 and STAU73 were resistant to oxacillin while STAU32 and STAU78 were sensitive, the genomic analysis identified only the blaZ operon corresponding to resistance to beta-lactams. However, the presence of the sdrC gene was revealed exclusively in resistant isolates, an important adhesin in the colonization process that potentiates pathogenicity in S. aureus. In addition, resistance islands (REIs) were identified in these isolates, suggesting more conserved REIs. In the analysis of SNPs throughout the genome, mutations were found in the trmB and smpB genes of the resistant isolates and in the murD and rimM genes of the sensitive isolates. This study highlights the potential benefit of genome-wide characterization tools to identify molecular mechanisms of S. aureus in bovine mastitis.
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Mastitis Bovina , Infecciones Estafilocócicas , Animales , Bovinos , Femenino , Humanos , Staphylococcus aureus , Antibacterianos/farmacología , Virulencia/genética , Tipificación de Secuencias Multilocus , Pruebas de Sensibilidad Microbiana , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estafilocócicas/microbiología , OxacilinaRESUMEN
Flavobacterial infection associated with diseased fish is caused by multiple bacterial species within the family Flavobacteriaceae. In the present study, the Chilean isolate FP99, from the gills of a diseased, farmed rainbow trout (Oncorhynchus mykiss), was characterized using phenotypic and genomic analyses. Additionally assessed was pathogenic activity. Phylogenetic analysis based on 16S rRNA gene sequencing confirmed that isolate FP99 belonged to the genus Epilithonimonas, an average nucleotide identity value of 100% was detected with the Chilean isolate identified as Epilithonimonas sp. FP211-J200. In silico genome analysis, mechanisms for toxins production, and superantigens, adhesion, or other genes associated with virulence were not detected. However, genes encoding proteins for antibiotic resistance were found, including the chrA gene and the nucleotide sequence that encodes for multiple antibiotic resistance MarC proteins. Furthermore, the blaESP-1 gene (87.85% aminoacidic sequence identity), encoding an extended-spectrum subclass B3 metallo-ß-lactamase and conferring carbapenem-hydrolysing activity, and the tet(X) gene, which encodes a monooxygenase that catalyses the degradation of tetracycline-class antimicrobials were carried by this isolate. Phenotyping analyses also supported assignment as E. ginsengisoli. Challenge trials against healthy rainbow trout resulted in no observed pathogenic effect. Our findings identify for the first time the species E. ginsengisoli as associated with fish farming, suggesting that this isolate may be a component of the microbiota of the freshwater system. Notwithstanding, poor environmental conditions and any stressors associated with aquaculture situations or lesions caused by other pathogenic bacteria, such as F. psychrophilum, could favour the entry of E. ginsengisoli into rainbow trout.