RESUMEN
Tilapia is one of the most important farmed fish in the world and the most cultivated in Brazil. The increase of this farming favors the appearance of diseases, including bacterial diseases. Therefore, the aim of this study was to evaluate the bactericidal activity of copaiba oil, Copaifera duckei, against Streptococcus agalactiae and Flavobacterium columnare and the dietary effect of copaiba oil on zootechnical performance, hematological, biochemical, immunological, and histological analysis before and after an intraperitoneal infection (body cavity) with S. agalactiae in Nile tilapia. For this, fish were randomly distributed into 15 fiber tanks in five treatments (0, 0.25, 0.50, 0.75, and 1.0%) and fed with a commercial diet supplemented with copaiba oil for 30 days. After this period, the fish were randomly redistributed for the experimental challenge with S. agalactiae into six treatments (T0, T1, T2, T3, T4, and T5), the fish were anesthetized, and blood samples were collected to assess hematological, biochemical, immunological, and histological parameters. Copaiba oil showed bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro. In addition, concentrations of 0.75 and 1.0% of copaiba oil have an anti-inflammatory effect and improve hematological and immunological parameters, increasing leukocyte numbers, albumin, and serum lytic activity. Furthermore, there is an increase in the intestinal villus length and tissue damage in groups at concentrations of 0.75 and 1.0% of copaiba oil. In conclusion, copaiba oil presented bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro, and oral supplementation at concentrations of 0.75 and 1.0% compared to the control group enhanced non-specific immune parameters and digestibility in Nile Tilapia.
Asunto(s)
Cíclidos , Suplementos Dietéticos , Enfermedades de los Peces , Flavobacterium , Streptococcus agalactiae , Animales , Streptococcus agalactiae/efectos de los fármacos , Flavobacterium/efectos de los fármacos , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/tratamiento farmacológico , Enfermedades de los Peces/prevención & control , Fabaceae/química , Antibacterianos/farmacología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/prevención & control , Aceites de Plantas/farmacología , Infecciones por Flavobacteriaceae/veterinaria , Infecciones por Flavobacteriaceae/microbiología , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Infecciones por Flavobacteriaceae/prevención & control , Alimentación Animal , Administración Oral , Acuicultura/métodosRESUMEN
A strategy for vaccine design involves identifying proteins that could be involved in pathogen-host interactions. The aim of this proteomic study was to determine how iron limitation affects the protein expression of Tenacibaculum dicentrarchi, with a primary focus on virulence factors and proteins associated with iron uptake. The proteomic analysis was carried out using two strains of T. dicentrarchi grown under normal (control) and iron-limited conditions, mimicking the host environment. Our findings revealed differences in the proteins expressed by the type strain CECT 7612T and the Chilean strain TdCh05 of T. dicentrarchi. Nonetheless, both share a common response to iron deprivation, with an increased expression of proteins associated with iron oxidation and reduction metabolism (e.g., SufA, YpmQ, SufD), siderophore transport (e.g., ExbD, TonB-dependent receptor, HbpA), heme compound biosynthesis, and iron transporters under iron limitation. Proteins involved in gliding motility, such as GldL and SprE, were also upregulated in both strains. A negative differential regulation of metabolic proteins, particularly those associated with amino acid biosynthesis, was observed under iron limitation, reflecting the impact of iron availability on bacterial metabolism. Additionally, the TdCh05 strain exhibited unique proteins associated with gliding motility machinery and phage infection control compared to the type strain. These groups of proteins have been identified as virulence factors within the Flavobacteriaceae family, including the genus Tenacibaculum. These results build upon our previous report on iron acquisition mechanisms and could lay the groundwork for future studies aimed at elucidating the role of some of the described proteins in the infectious process of tenacibaculosis, as well as in the development of potential vaccines.
Asunto(s)
Proteínas Bacterianas , Enfermedades de los Peces , Infecciones por Flavobacteriaceae , Hierro , Oxidación-Reducción , Proteómica , Tenacibaculum , Regulación hacia Arriba , Hierro/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Infecciones por Flavobacteriaceae/veterinaria , Infecciones por Flavobacteriaceae/microbiología , Animales , Enfermedades de los Peces/microbiología , Tenacibaculum/genética , Tenacibaculum/metabolismo , Proteoma , Factores de Virulencia/metabolismo , Factores de Virulencia/genética , Lubina/microbiologíaRESUMEN
The diversity of Tenacibaculum maritimum in Chile remains poorly understood, particularly in terms of antigenic and genetic diversity. This information is crucial for the future development of a vaccine against tenacibaculosis and would increase understanding of this important fish pathogen. With this aim, the biochemical, antigenic, and genetic characteristics were analysed for 14 T. maritimum isolates, recovered from diseased Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) farmed in Chile between 1998 and 2022. Biochemical analysis showed a homogeneity among all the Chilean T. maritimum isolates and all four other strains included for comparison purposes. Serological characterization using dot-blot assaying revealed antigenic heterogeneity with the use of unabsorbed antisera. The majority of isolates showed cross-reactions, identifying three main serological patterns. When the PCR-based serotyping scheme was performed, the existence of antigenic heterogeneity was confirmed. Four Atlantic salmon isolates were 4-0; and most isolates, including the rainbow trout isolate, were 3-1 (n = 9). A turbot (Scophthalmus maximus) isolate was 1-0. Using an existing Multilocus Sequence Typing system, two newly identified sequence types (ST193 and ST198) in the database were detected. ST193 encompassed nine isolates obtained from Atlantic salmon and rainbow trout, while ST198 regrouped four isolates, all retrieved from diseased Atlantic salmon in 2022. These findings highlight significant antigenic and genetic diversity among the Chilean isolates. This information is useful for epizootiology and the selection of suitable candidate strain(s) for vaccine development against tenacibaculosis caused by T. maritimum in Chilean salmon farming.
Asunto(s)
Enfermedades de los Peces , Infecciones por Flavobacteriaceae , Oncorhynchus mykiss , Salmo salar , Tenacibaculum , Animales , Enfermedades de los Peces/microbiología , Tenacibaculum/genética , Tenacibaculum/aislamiento & purificación , Infecciones por Flavobacteriaceae/veterinaria , Infecciones por Flavobacteriaceae/microbiología , Chile/epidemiología , Oncorhynchus mykiss/microbiología , Variación Genética , Serotipificación/veterinaria , Heterogeneidad Genética , AcuiculturaRESUMEN
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.
Asunto(s)
Chryseobacterium , Enfermedades de los Peces , Infecciones por Flavobacteriaceae , Oncorhynchus mykiss , Animales , Oncorhynchus mykiss/microbiología , Chile , Flavobacterium , ARN Ribosómico 16S/genética , Filogenia , Enfermedades de los Peces/microbiología , Genómica , Infecciones por Flavobacteriaceae/microbiologíaRESUMEN
Flavobacterium psychrophilum is a pathogenic bacterium affecting Chilean salmonid farms. High antigenic and genetic diversity exists among Chilean F. psychrophilum isolates, but the distribution thereof among farms is poorly understood. These epidemiological data are key for developing isolate-specific vaccines. The present study isolated F. psychrophilum in diseased Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) from five freshwater farms between 2018 and 2019. Each farm only raised one salmonid species and was geographically separated from and did not share culturing water with the other farms. Antigenic and genetic analyses were conducted to shed light on the possibility of isolates coexisting within the same farm during outbreaks. A total of 68 Chilean F. psychrophilum isolates were recovered from skin lesions, gills, fins, kidney and spleen of moribund and live fish. Among the 68 Chilean isolates, mPCR-serotyping indicated three major serotypes (i.e. 23.5% type 0; 47.1% type 2; and 26.5% type 4) and, to a lesser degree, serotype 1 (2.9%). Sixteen antigenic groups were detected by slide agglutination. Genetic characterizations by 16S rRNA alleles identified 71% of the isolates as the virulent genogroup CSF259-93 allele. A predominant serotype was associated with each farm, with types 0 and 4 related to Atlantic salmon and types 1 and 2 to rainbow trout. Notwithstanding, several antigenic groups coexisted within some farms. Likewise, the experimental intramuscular challenges (n = 20) demonstrated that the type-2 isolates from rainbow trout were the most pathogenic among isolates recovered from infectious outbreaks in Atlantic salmon, especially as compared to those from types-0 and -4. These results allow us to suggest that prevention measures, specifically vaccines, should be developed according to dominant isolates and with specificity to each farm, that is the use of autogenous or site-specific vaccines.
Asunto(s)
Enfermedades de los Peces , Infecciones por Flavobacteriaceae , Oncorhynchus mykiss , Animales , Chile/epidemiología , ARN Ribosómico 16S/genética , Enfermedades de los Peces/epidemiología , Enfermedades de los Peces/microbiología , Oncorhynchus mykiss/microbiología , Flavobacterium , Brotes de Enfermedades/veterinaria , Infecciones por Flavobacteriaceae/epidemiología , Infecciones por Flavobacteriaceae/veterinaria , Infecciones por Flavobacteriaceae/microbiologíaRESUMEN
INTRODUCCIÓN: Elizabethkingia es un género de bacterias gramnegativas cuya relevancia como patógeno oportunista en hospederos inmunocomprometidos y pacientes críticos ha sido reconocida progresivamente en los últimos años. Este género está compuesto principalmente por E. meningoseptica, E. anophelis y E. miricola. Si bien inicialmente E. meningoseptica fue considerada la especie patógena más relevante, gracias a los avances en las técnicas de identificación microbiológica se ha reconocido a E. anophelis como el principal patógeno de este grupo. OBJETIVO: Caracterizar los casos de infecciones por Elizabethkingia spp. en una red de salud y realizar una breve revisión de esta infección. MATERIAL Y MÉTODOS: Se realizó una revisión de los cultivos positivos para Elizabethkingia spp. en el Laboratorio de Microbiología de la Red de Salud UC-CHRISTUS (Chile) entre los años 2017 y 2021. RESULTADOS: Se obtuvo 17 cultivos positivos correspondientes a siete casos clínicos, todos procedentes de un hospital universitario. Todos los casos poseían factores de riesgo conocidos de infección por Elizabethkingia spp. incluyendo uso de antimicrobianos recientes, por ejemplo, el uso previo de carbapenémicos en 85,7% de los pacientes. Cuatro casos se presentaron en pacientes con neumonía por SARS-CoV-2, una coinfección no previamente reportada en la literatura. Elizabethkingia anophelis fue identificada mediante secuenciación de ARN ribosomal en 80% de las cepas recuperadas, lo que corresponde al primer reporte de esta especie en Chile CONCLUSIÓN: Comunicamos la experiencia clínica de infecciones por este género en un hospital universitario de Chile, incluyendo los primeros casos de coinfección en pacientes cursando neumonía por SARS-CoV-2 y la primera identificación de Elizabethkingia anophelis en Chile.
BACKGROUND: Elizabethkingia is a genus of gramnegative bacteria whose relevance as an opportunistic pathogen in immunosuppressed hosts and critically ill patients has been progressively recognized in recent years. This genus is mainly composed of E. meningoseptica, E. anophelis, and E. miricola. Although E. meningoseptica was initially reported as the most relevant pathogenic species, thanks to advances in microbiological identificaron techniques E. anophelis has been recognized as the main pathogen of this group. AIM: To characterize Elizabethkingia spp.'s infections in a health network and make a brief review of this infection. METHOD: We conducted a review of clinical cultures that were positive for Elizabethkingia sp. in the Microbiology Laboratory of the UC-CHRISTUS Health Network (Chile), between 2017 and 2021. RESULTS: Seventeen positive cultures were obtained corresponding to seven clinical cases, all originating from a university hospital. All cases had known risk factors for Elizabethkingia sp. infection, including recent use of antibiotics. Notably, previous use of carbapenems was present in 85.7% of the patients. Four cases occurred in patients with SARS-CoV-2 pneumonia, a coinfection not previously reported in the literature. Elizabethkingia anophelis was identified by ribosomal RNA sequencing in 80% of the recovered strains, which corresponds to the first report of this species in Chile. CONCLUSION: We report the clinical experience of a university hospital with infections by Elizabethkingia spp., including the first cases of coinfection in patients with SARS-CoV-2 pneumonía and the first identification of Elizabethkingia anophelis in Chile.
Asunto(s)
Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Infecciones por Flavobacteriaceae/microbiología , Infecciones por Flavobacteriaceae/epidemiología , Coinfección/epidemiología , COVID-19/epidemiología , Chile/epidemiología , Flavobacteriaceae , SARS-CoV-2 , Hospitales UniversitariosRESUMEN
Tenacibaculum dicentrarchi is an emerging pathogen for salmonid cultures and red conger eel (Genypterus chilensis) in Chile, causing high economic losses not only in Chile but also to the global salmon industry. Infected fish show severe gross skin lesions that are sometimes accompanied by bone exposure. Despite pathogenicity demonstrated by Koch's postulates, no knowledge is currently available regarding the virulence machinery of T. dicentrarchi strains. Comparisons between the genome sequences of the eight T. dicentrarchi strains obtained from G. chilensis and Atlantic salmon (Salmo salar) provide insights on the existence of genomic diversity within this bacterium. The T. dicentrarchi type strain 3509T was used as a reference genome. Depending on the T. dicentrarchi strain, the discovered diversity included genes associated with iron acquisition mechanisms, copper homeostasis encoding, resistance to tetracycline and fluoroquinolones, pathogenic genomic islands and phages. Interestingly, genes encoding the T9SS membrane protein PorP/SprF were retrieved in all of the analysed T. dicentrarchi strains, regardless of the host fish (i.e. red conger eel or Atlantic salmon). However, the T6SS core component protein VgrG was identified in only one Atlantic salmon strain. Three types of peptidase genes and proteins associated with quorum sensing were detected in all of the T. dicentrarchi strains. In turn, all eight strains presented a total of 17 proteins associated with biofilm formation, which was previously confirmed through physiological studies. This comparative analysis will help elucidate and describe the genes and pathways that are likely involved in the virulence process of T. dicentrarchi. All or part of these predicted genes could aid the pathogen during the infective process in fish, making further physiological research necessary for clarification.
Asunto(s)
Enfermedades de los Peces/microbiología , Genoma Bacteriano , Tenacibaculum/genética , Virulencia , Animales , Acuicultura , Chile , Anguilas/microbiología , Infecciones por Flavobacteriaceae/microbiología , Infecciones por Flavobacteriaceae/veterinaria , Salmo salar/microbiologíaRESUMEN
Lactic acid bacteria are a powerful vehicle for releasing of cytokines and immunostimulant peptides at the gastrointestinal level after oral administration. However, its therapeutic application against pathogens that affect rainbow trout and Atlantic salmon has been little explored. Type II interferon in Atlantic salmon activates the antiviral response, protecting against viral infection, but its role against bacterial infection has not been tested in vivo. In this work, through the design of a recombinant lactic acid bacterium capable of producing Interferon gamma from Atlantic salmon, we explore its role against bacterial infection and the ability to stimulate systemic immune response after oral administration of the recombinant probiotic. Recombinant interferon was active in vitro, mainly stimulating IL-6 expression in SHK-1 cells. In vivo, oral administration of the recombinant probiotic produced an increase in IL-6, IFNγ and IL-12 in the spleen and kidney, in addition to stimulating the activity of lysozyme in serum. The challenge trials indicated that the administration of the IFNγ-producing probiotic doubled the survival in fish infected with F. psychrophilum. In conclusion, our results showed that the oral administration of lactic acid bacteria producing IFNγ managed to stimulate the immune response at a systemic level, conferring protection against pathogens, showing a biotechnological potential for its application in aquaculture.
Asunto(s)
Proteínas de Peces/metabolismo , Infecciones por Flavobacteriaceae/prevención & control , Flavobacterium/patogenicidad , Interferón gamma/metabolismo , Lactococcus lactis/metabolismo , Oncorhynchus mykiss/microbiología , Probióticos/administración & dosificación , Administración Oral , Animales , Línea Celular , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Infecciones por Flavobacteriaceae/inmunología , Infecciones por Flavobacteriaceae/metabolismo , Infecciones por Flavobacteriaceae/microbiología , Flavobacterium/inmunología , Interacciones Huésped-Patógeno , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-12/metabolismo , Interleucina-6/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/inmunología , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/inmunología , Oncorhynchus mykiss/metabolismo , FilogeniaRESUMEN
The present study reports on the first isolation of Tenacibaculum maritimum in rainbow trout (Oncorhynchus mykiss) farmed in Chile. In March 2020, two cages raising rainbow trout (~250 g) in the Los Lagos Region suffered a disease outbreak. In total, 17,554 fish died (3.5%-4.8% accumulated mortality). Microbiological analysis of the diseased fish obtained two representative isolates (i.e. Tm-035 and Tm-036). These were obtained from the external gross skin lesions-typical of tenacibaculosis-of two fish. Phenotyping, PCR tests and sequencing of the 16S rRNA and housekeeping genes confirmed the isolates as T. maritimum. The pathogenic potential of Tm-035 was further assessed by bath challenging Atlantic salmon (Salmo salar), which killed 70 ± 15% of fish within 11 days. Dead fish presented the same external clinical signs as did the farmed rainbow trout specimens. This research further broadens the known host distribution of this pathogen. Furthermore, the virulence experiments demonstrated that T. maritimum does not have a specific host. Additional studies are needed to evaluate the risk of T. maritimum for the O. mykiss farming industry.
Asunto(s)
Enfermedades de los Peces/microbiología , Infecciones por Flavobacteriaceae/veterinaria , Oncorhynchus mykiss , Tenacibaculum/aislamiento & purificación , Animales , Chile , Infecciones por Flavobacteriaceae/microbiologíaRESUMEN
BACKGROUND: Elizabethkingia is a genus of gramnegative bacteria whose relevance as an opportunistic pathogen in immunosuppressed hosts and critically ill patients has been progressively recognized in recent years. This genus is mainly composed of E. meningoseptica, E. anophelis, and E. miricola. Although E. meningoseptica was initially reported as the most relevant pathogenic species, thanks to advances in microbiological identificaron techniques E. anophelis has been recognized as the main pathogen of this group. AIM: To characterize Elizabethkingia spp.'s infections in a health network and make a brief review of this infection. METHOD: We conducted a review of clinical cultures that were positive for Elizabethkingia sp. in the Microbiology Laboratory of the UC-CHRISTUS Health Network (Chile), between 2017 and 2021. RESULTS: Seventeen positive cultures were obtained corresponding to seven clinical cases, all originating from a university hospital. All cases had known risk factors for Elizabethkingia sp. infection, including recent use of antibiotics. Notably, previous use of carbapenems was present in 85.7% of the patients. Four cases occurred in patients with SARS-CoV-2 pneumonia, a coinfection not previously reported in the literature. Elizabethkingia anophelis was identified by ribosomal RNA sequencing in 80% of the recovered strains, which corresponds to the first report of this species in Chile. CONCLUSION: We report the clinical experience of a university hospital with infections by Elizabethkingia spp., including the first cases of coinfection in patients with SARS-CoV-2 pneumonía and the first identification of Elizabethkingia anophelis in Chile.
Asunto(s)
COVID-19 , Coinfección , Infecciones por Flavobacteriaceae , COVID-19/epidemiología , Chile/epidemiología , Coinfección/epidemiología , Flavobacteriaceae , Infecciones por Flavobacteriaceae/epidemiología , Infecciones por Flavobacteriaceae/microbiología , Hospitales Universitarios , Humanos , SARS-CoV-2RESUMEN
The success and sustainability of Chilean aquaculture largely depends on the control of endemic and emerging pathogens, including several species of the genus Tenacibaculum. Tenacibaculum dicentrarchi and "Tenacibaculum finnmarkense" have been detected and confirmed in Chilean Atlantic salmon (Salmo salar). However, no outbreaks of tenacibaculosis in rainbow trout (Oncorhynchus mykiss) or coho salmon (Oncorhynchus kisutch) have been reported, either in Chile or globally. The aims of this study were to determine whether the mortalities recorded for rainbow trout and coho salmon from five marine fish farms located in the Los Lagos, Aysén, and Magallanes Regions could be caused by Tenacibaculum spp. The diseased fish exhibited cutaneous haemorrhages, tail and peduncle rots, and damage on the mouth and tongue. Microbiological analysis of infected external tissues yielded 13 bacterial isolates. The isolates were identified as members of the genus Tenacibaculum through biochemical analysis (e.g. Gram-stain negative, straight rods, filamentous cells and motile by gliding), but differences existed in biochemical results, making species-level identification through biomolecular tools essential. The 16S rRNA analysis found that the majority of isolates were more closely related to "T. finnmarkense" than T. dicentrarchi, while the phylogenetic trees resulting from multilocus sequence data recovered the four main clades (clades I to IV) identified by Olsen et al. (2017, Veterinary Microbiology, 205, 39). This is the first documented occurrence of clinical tenacibaculosis in farmed rainbow trout and coho salmon globally, and it extends the known host distribution of this pathogen in Chile. Moreover, we confirm the presence of Tenacibaculum species in the Chilean Patagonia. These findings highlight the importance of establishing preventative measures to minimize the spread of this disease within the Chilean marine aquaculture industry, as well as the need for monitoring initiatives worldwide in these farmed fish species.
Asunto(s)
Enfermedades de los Peces/microbiología , Infecciones por Flavobacteriaceae/veterinaria , Tenacibaculum/aislamiento & purificación , Animales , Acuicultura , Chile/epidemiología , Enfermedades de los Peces/epidemiología , Infecciones por Flavobacteriaceae/epidemiología , Infecciones por Flavobacteriaceae/microbiología , Oncorhynchus kisutch , Oncorhynchus mykiss , Filogenia , ARN Ribosómico 16S , Tenacibaculum/clasificación , Tenacibaculum/genéticaRESUMEN
Chile is currently the second largest producer of farmed salmon worldwide, but Flavobacterium psychrophilum, as one of the most detrimental pathogens, is responsible for major losses during the freshwater culturing step in salmonid fish farms. An antigenic study conducted 10 years ago reported four serological groups using 20 F. psychrophilum Chilean strains. To reduce disease outbreaks and to develop vaccine candidates, antigenic knowledge needs to be regularly updated using a significant number of additional recent F. psychrophilum isolates. The present study aimed at investigating the serological diversity of 118 F. psychrophilum isolates collected between 2006 and 2018 from farmed Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch). The current study supports an expansion of the known antigenic groups in Chile from 4 to 14. However, the use of the slide-agglutination technique for serotyping is costly, is labour-intensive and requires significant technical expertise. Addressing these points, the mPCR-based procedure was a very useful tool for serotyping the collected Chilean F. psychrophilum isolates. This technique revealed the presence of diverse mPCR serotypes (i.e. types 0, 1, 2 and 4). Therefore, mPCR should be employed to select the bacterial strain(s) for vaccine development and to conduct follow-up, selective breeding or epidemiological surveillance in Chilean fish farms. Given the presented findings, changes to Chilean fish-farming practices are vital for ensuring the continued productivity and well-being of farmed salmonids.
Asunto(s)
Enfermedades de los Peces/microbiología , Infecciones por Flavobacteriaceae/veterinaria , Flavobacterium/aislamiento & purificación , Oncorhynchus kisutch , Oncorhynchus mykiss , Salmo salar , Pruebas Serológicas/veterinaria , Animales , Chile , Explotaciones Pesqueras , Infecciones por Flavobacteriaceae/microbiologíaRESUMEN
Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout syndrome in freshwater salmonid fish worldwide, generating injuries and high mortality rates. Despite several studies on this bacterium, the infection mechanism remains unknown due to limitations in the employed animal models. In this work, we propose using zebrafish (Danio rerio) as a model for studying bacterial pathogenicity. To substantiate this proposal, zebrafish infection by F. psychrophilum strain JIP 02/86 was characterized. Zebrafish larvae were infected using the bath method, and morphological changes and innate immune system activation were monitored using transgenic fish. Salmonid-like infection phenotypes were observed in 4.74% of treated larvae, as manifested by fin, muscle and caudal peduncle damage. Symptomatic and dead larvae accounted for 1.35% of all challenged larvae. Interestingly, infected larvae with no infection phenotypes showed stronger innate immune system activation than specimens with phenotypes. A failure of function assay for myeloid factor pu.1 resulted in more infected larvae (up to 43.5%), suggesting that low infection rates by F. psychrophilum would be due to the protective actions of the innate immune system against this bacterium in zebrafish larvae. Our results support the use of zebrafish as an infection model for studying F. psychrophilum. Furthermore, the percentage of infected fish can be modulated by disturbing, to varying extents, the differentiation of myeloid cells. Using this evidence as a starting point, different aspects of the infection mechanism of F. psychrophilum could be studied in vivo.
Asunto(s)
Modelos Animales de Enfermedad , Enfermedades de los Peces/microbiología , Infecciones por Flavobacteriaceae/veterinaria , Flavobacterium/fisiología , Pez Cebra , Animales , Infecciones por Flavobacteriaceae/microbiologíaRESUMEN
Elizabethkingia meningoseptica is a widespread gram-negative bacillus in the environment, but a rarely reported human pathogen presenting mostly as nosocomial infections. Advances in neonatal intensive care facilities and usage of sophisticated medical devices strengthen the invasive infectious potential of the microorganism. Clinical manifestations usually include primary bacteremia, meningitis, nosocomial pneumoniae, intravascular catheter-related bacteremia and gastrointestinal and biliary tract infections. Lack of improved diagnostic systems in resource constrained settings, might be a cause of underreporting of such infections. Discrimination between colonization and infection is quite difficult, and it has an unusual antibiotic susceptibility pattern. Therefore clinicians should pay special attention to accurate diagnosis in order to prevent mistreatment. Here we report three newborn cases with the diagnosis of E. meningoseptica infection and colopnization, with the aim of drawing attention to the diagnosis and management of this rare but lethal bacteria that is already present in the intensive care unit environment.
Elizabethkingia meningoseptica es un bacilo gramnegativo ampliamente distribuido en la naturaleza pero poco frecuente en humanos que se presenta en infecciones intrahospitalarias. Los avances en las instalaciones de cuidados intensivos neonatales y el uso de dispositivos médicos sofisticados fortalecen la capacidad infecciosa invasiva del microorganismo. Las manifestaciones clínicas suelen incluir bacteriemia primaria, meningitis, neumonía intrahospitalaria, bacteriemia relacionada con el uso de catéteres intravasculares e infecciones gastrointestinales y de las vías biliares. Es posible que, en entornos con recursos limitados, la falta de sistemas de diagnóstico mejorados sea una de las causas por las que no se notifican todas esas infecciones. Resulta bastante difícil distinguir entre colonización e infección, y el patrón de sensibilidad a los antibióticos es diferente. Por consiguiente, los médicos deben realizar el diagnóstico preciso para así evitar el tratamiento incorrecto. En este artículo, describimos tres casos de recién nacidos con diagnóstico de infección y colonización por E. meningoseptica con el objetivo de destacar la importancia del diagnóstico y el tratamiento oportunos de esta bacteria poco frecuente pero letal que ya está presente en las unidades de cuidados intensivos.
Asunto(s)
Infección Hospitalaria/diagnóstico , Infecciones por Flavobacteriaceae/diagnóstico , Flavobacteriaceae/aislamiento & purificación , Antibacterianos/administración & dosificación , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/microbiología , Femenino , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Infecciones por Flavobacteriaceae/microbiología , Humanos , Recién Nacido , Recien Nacido Prematuro , Unidades de Cuidado Intensivo Neonatal , MasculinoRESUMEN
Flavobacterium psychrophilum is the etiologic agent of rainbow trout fry syndrome (RTFS). This pathogen infects a wide variety of salmonid species during freshwater stages, causing significant losses in the aquaculture industry. Rainbow trout (Oncorhynchus mykiss) infected with F. psychrophilum, presents as the main external clinical sign ulcerative lesions and necrotic myositis in skeletal muscle. We previously reported the in vitro cytotoxic activity of F. psychrophilum on rainbow trout myoblast, however little is known about the molecular mechanisms underlying the in vivo pathogenesis in skeletal muscle. In this study, we examined the transcriptomic profiles of skeletal muscle tissue of rainbow trout intraperitoneally challenged with low infection dose of F. psychrophilum. Using high-throughput RNA-seq, we found that 233 transcripts were up-regulated, mostly associated to ubiquitin mediated proteolysis and apoptosis. Conversely, 189 transcripts were down-regulated, associated to skeletal muscle contraction. This molecular signature was consistent with creatine kinase activity in plasma and oxidative damage in skeletal muscle. Moreover, the increased caspase activity suggests as a whole skeletal muscle atrophy induced by F. psychrophilum. This study offers an integrative analysis of the skeletal muscle response to F. psychrophilum infection and reveals unknown aspects of its pathogenesis in rainbow trout.
Asunto(s)
Enfermedades de los Peces/genética , Infecciones por Flavobacteriaceae/veterinaria , Flavobacterium/fisiología , Oncorhynchus mykiss/genética , Transcriptoma , Animales , Acuicultura , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/patología , Infecciones por Flavobacteriaceae/genética , Infecciones por Flavobacteriaceae/microbiología , Infecciones por Flavobacteriaceae/patología , Interacciones Huésped-Patógeno , Músculo Esquelético/metabolismo , Músculo Esquelético/microbiología , Músculo Esquelético/patología , Oncorhynchus mykiss/microbiologíaRESUMEN
The aim of this study was to examine the histopathological and immunohistochemical changes caused by natural and experimentally-induced Ornithobacterium rhinotracheale infection in the respiratory system of chickens. To this end, three different studies were carried out. The first was a retrospective study of 82 field cases with respiratory disorders compatible with O. rhinotracheale infection. The bacterium was immunohistochemically detected in the lungs in 48 of 82 field cases, and 50 ß-haemolytic (BH) and non-haemolytic (NH) strains were isolated. In the second study, an experimental model of the disease was created using 3-week-old broiler chickens, to identify possible differences of pathogenicity between the BH and NH isolates by the intravenous (IV) and intratracheal (IT) inoculation routes (IR). The group challenged with the NH isolate showed more severe lung lesions than the group challenged with the BH isolate at 7-days postinoculation (p.i.). The 14-day p.i. groups challenged with either the BH or NH isolates by the IT or IV IR had a higher histologic grade of pulmonary and hepatic lesions and a higher total histologic grade of lesions suggesting more severe pathology with longer time of exposure. A direct association between the inoculation routes and the organs affected was shown. Finally, a slaughterhouse study was carried out from October 2014 to May 2015, in which the histologic grade of lesions was significantly higher in immunohistochemically positive for O. rhinotracheale lungs of dead-on-arrival chickens.
Asunto(s)
Infecciones por Flavobacteriaceae/microbiología , Ornithobacterium/patogenicidad , Enfermedades de las Aves de Corral/microbiología , Mataderos , Bienestar del Animal , Animales , Pollos , Infecciones por Flavobacteriaceae/patología , Inmunohistoquímica/veterinaria , Enfermedades de las Aves de Corral/patología , Estudios Prospectivos , Sistema Respiratorio/microbiología , Sistema Respiratorio/patología , Estudios RetrospectivosRESUMEN
Elizabethkingia meningoseptica is an opportunistic pathogen with a high mortality and an increasing incidence in the intensive care units. We present a 4-year-old patient with a history of atresia of the biliary tract and a liver transplant at 11 months of age, who was admitted for acute respiratory infection with hypoxemia. During the hospitalization, she required mechanical ventilation. Due to persistent fever and hypoxemia, mini bronchoalveolar lavage was performed with a positive culture for Elizabethkingia meningoseptica. She received vancomycin, trimethoprim/sulfamethoxazole and ciprofloxacin for 14 days with a good response. A chest tomography showed the presence of mosaic hypoperfusion, cystic images, and bilateral bronchiectasis. During the following 2 years, she presented good clinical progress, with scarce respiratory infections, isolated symptoms and good tolerance to exercise. The resolution of the majority of the initial lesions was evidenced at 20 months of follow-up.
Elizabethkingia meningoseptica es un patógeno oportunista, con una elevada mortalidad y una incidencia en aumento en las terapias intensivas. Se presenta a una paciente de 4 años con antecedente de atresia de vías biliares y trasplante hepático a los 11 meses de vida, que se internó por infección respiratoria aguda baja con hipoxemia. Durante la internación, sufrió un empeoramiento clínico con requerimiento de asistencia respiratoria mecánica. Por fiebre e hipoxemia persistente, se realizó un minilavado broncoalveolar, con cultivo positivo para Elizabethkingia meningoseptica. Recibió vancomicina, trimetoprima/sulfametoxazol y ciprofloxacina durante 14 días, con buena respuesta. Una tomografía de tórax evidenció la presencia de hipoperfusión en mosaico, imágenes quísticas y bronquiectasias bilaterales. Durante los siguientes 2 años, presentó una buena evolución clínica, con escasas intercurrencias respiratorias, síntomas intercrisis aislados y buena tolerancia al ejercicio. En las imágenes de control, se evidenció la resolución de la mayoría de las lesiones iniciales a los 20 meses de su seguimiento.
Asunto(s)
Antibacterianos/administración & dosificación , Chryseobacterium/aislamiento & purificación , Infecciones por Flavobacteriaceae/diagnóstico , Neumonía Bacteriana/diagnóstico , Preescolar , Femenino , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Infecciones por Flavobacteriaceae/microbiología , Estudios de Seguimiento , Humanos , Unidades de Cuidados Intensivos , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiologíaRESUMEN
Chryseobacterium indologenes is an emerging nosocomial pathogen that produces IND-type chromosomal metallo-beta-lactamase. The phenotype and molecular aspects of two multidrug resistant C. indologenes strains and the analysis of the tertiary structure of the IND enzyme were studied. Identification of species and susceptibility tests were performed using the Vitek-2 compact. Chromosomal and plasmid DNA were extracted using PureLink™ Genomic DNA Mini Kit and PureLink Quick Plasmid Miniprep Kit, and the sequencing was performed using ABI 3130 genetic analyzer. Two strains were isolated and are registered as P-23 and P-113. Of the two, P-113 was sensitive to ciprofloxacin and cefepime only, whereas the P-23 showed reduced sensitivity to ceftazidime, ciprofloxacin, and tigecycline. The genetic analysis of both isolates identified the presence of the blaIND-like gene, with similarity to IND-3 and IND-8 alleles. The IND-3 identified in the P-133 sample presented a single mutation at position T355G, which corresponds to a nonsynonymous substitution of the amino acid at position 119 (SerâAla). The phylogenetic analysis of INDs showed lineages that are circulating in Asian and European countries. These results emphasize the need for effective preventive actions to avoid the dissemination of this type of pathogen in the hospital environment.
Asunto(s)
Antibacterianos/farmacología , Chryseobacterium/genética , Infección Hospitalaria/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Flavobacteriaceae/microbiología , beta-Lactamasas/genética , Anciano de 80 o más Años , Sustitución de Aminoácidos , Brasil , Cefepima/farmacología , Ceftazidima/farmacología , Cromosomas Bacterianos/química , Cromosomas Bacterianos/metabolismo , Chryseobacterium/clasificación , Chryseobacterium/efectos de los fármacos , Chryseobacterium/aislamiento & purificación , Ciprofloxacina/farmacología , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/patología , Femenino , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Infecciones por Flavobacteriaceae/patología , Expresión Génica , Humanos , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Modelos Moleculares , Filogenia , Plásmidos/química , Plásmidos/metabolismo , Mutación Puntual , Estructura Secundaria de Proteína , Tigeciclina/farmacologíaRESUMEN
Flavobacterium psychrophilum is the etiologic agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), which cause significant worldwide losses in aquaculture. Juvenile rainbow trout are particularly susceptible to F. psychrophilum infection, the main external clinical signs of which are extensive necrotic myositis and ulcerative lesions. Despite the economic relevance of this pathogen in aquaculture, little is known about the molecular mechanisms underlying F. psychrophilum infection and pathogenesis. In this study, cultured skeletal muscle cells from rainbow trout (Oncorhynchus mykiss) were co-incubated with the virulent strain of F. psychrophilum JIP02/86 (ATCC 49511). Trypan blue exclusion analysis at 48h post-incubation revealed decreased cellular viability. Direct bacteria-myoblast contact was found a key factor in inducing F. psychrophilum cytotoxicity. Apoptosis was characterized by nuclear DNA fragmentation, decreased plasma membrane integrity, increased caspase activity, and the proteolytic cleavage of poly(ADP-ribose)polymerase-1 (PARP-1). Moreover, bacterial infection induced an early inhibition of NF-κB signaling, as well as a differential expression of the pro- and anti-apoptotic genes, bax and bcl-2. These findings suggest that F. psychrophilum induces rainbow trout muscle apoptosis through the modulation of the NF-κB signaling as a mechanism for nutrient acquisition and survival.