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INTRODUCTION: Clinical reasoning (CR) is a key competence for physicians and a major source of damaging medical errors. Many strategies have been explored to improve CR quality, most of them based on knowledge enhancement, cognitive debiasing and the use of analytical reasoning. If increasing knowledge and fostering analytical reasoning have shown some positive results, the impact of debiasing is however mixed. Debiasing and promoting analytical reasoning have also been criticised for their lack of pragmatism. Alternative means of increasing CR quality are therefore still needed. Because emotions are known to influence the quality of reasoning in general, we hypothesised that emotional competence (EC) could improve physicians' CR. EC refers to the ability to identify, understand, express, regulate and use emotions. The influence of EC on CR remains unclear. This article presents a scoping review protocol, the aim of which will be to describe the current state of knowledge concerning the influence of EC on physicians' CR, the type of available literature and finally the different methods used to examine the link between EC and CR. METHOD AND ANALYSIS: The population of interest is physicians and medical students. EC will be explored according to the model of Mikolajczak et al, describing five major components of EC (identify, understand, express, regulate and use emotions). The concept of CR will include terms related to its processes and outcomes. Context will include real or simulated clinical situations. The search for primary sources and reviews will be conducted in MEDLINE (via Ovid), Scopus and PsycINFO. The grey literature will be searched in the references of included articles and in OpenGrey. Study selection and data extraction will be conducted using the Covidence software. Search and inclusion results will be reported using the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping review model (PRISMA-ScR). ETHICS AND DISSEMINATION: There are no ethical or safety concerns regarding this review. REGISTRATION DETAILS: OSF Registration DOI: https://doi.org/10.17605/OSF.IO/GM7YD.
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Médicos , Estudiantes de Medicina , Humanos , Razonamiento Clínico , Proyectos de Investigación , Revisiones Sistemáticas como Asunto , Literatura de Revisión como AsuntoRESUMEN
Staphylococcus aureus infection is a common cause of mastitis, reducing milk yield, affecting animal welfare and causing huge economic losses within the dairy industry. In addition to the problem of acquired drug resistance, bacterial invasion into udder cells and the formation of surface biofilms are believed to reduce antibiotic efficacy, leading to treatment failure. Here, we investigated the antimicrobial activities of enrofloxacin, an antibiotic that is commonly used in mastitis therapy and polyhexamethylene biguanide (PHMB), an antimicrobial polymer. The antimicrobial activities were tested against intracellular S. aureus in infected Mac-T cells (host cells). Also, fluorescein-tagged PHMB was used to study PHMB uptake and localization with S. aureus within the infected Mac-T cells. Anti-biofilm activities were tested by treating S. aureus biofilms and measuring effects on biofilm mass in vitro. Enrofloxacin and PHMB at 15 mg/L killed between 42 to 92 and 99.9% of intracellular S. aureus, respectively. PHMB-FITC entered and colocalized with the intracellular S. aureus, suggesting direct interaction of the drug with the bacteria inside the host cells. Enrofloxacin and PHMB at 15 mg/L reduced between 10 to 27% and 28 to 37% of biofilms' mass, respectively. The half-maximal inhibitory concentrations (IC50) obtained from a cytotoxicity assay were 345 ± 91 and 21 ± 2 mg/L for enrofloxacin and PHMB, respectively; therefore, both compounds were tolerated by the host cells at high concentrations. These findings suggest that both antimicrobials are effective against intracellular S. aureus and can disrupt biofilm structures, with PHMB being more potent against intracellular S. aureus, highlighting the potential application of PHMB in mastitis therapy.
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Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment.
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Biopelículas , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/clasificación , Staphylococcus aureus/fisiología , Animales , Cápsulas Bacterianas/química , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Bovinos , Femenino , Genoma Bacteriano , Espacio Intracelular/microbiología , Especificidad de la Especie , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Transactivadores/genética , Factores de Virulencia/genéticaRESUMEN
Staphylococcus (S.) aureus is one of the most important pathogens causing bovine mastitis. The aim of the present work was to follow in three herds and during the 3 years the clonality of S. aureus isolated from California Mastitis Test (CMT)-positive cows at the experimental station of Toukounous (Niger) by (i) comparing their pulsed field gel electrophoresis (PFGE) fingerprints, (ii) identifying their virulotypes by PCR amplification and (iii) assessing the production of capsule and the formation of biofilm. The 88 S. aureus isolates belonged to 14 different pulsotypes, 3 of them being predominant: A (30 %), D (27 %), B (15 %). A and B pulsotypes had the highest profile similarity coefficient (94 %), while others had similarity coefficients under 60 %. Seventy-five S. aureus isolates were further studied for their virulotypes, capsular antigens and biofilm production. Most surface factor-, leukocidin- and haemolysin-, but not the enterotoxin-encoding genes were detected in the majority (>75 %) of the isolates and were evenly distributed between the A, B and D pulsotype isolates. The majority of the 72 S. aureus positive with the cap5H or cap8H PCR produced the CP5 (82 %) or the CP8 (88 %) capsular antigen, respectively. Biofilm production by the 57 icaA-positive isolates was strong for 8 isolates, moderate for 31 isolates but weak for 18 isolates, implying that the icaA gene may not be expressed in vitro by one third of the positive isolates. Similar to other studies, those results confirm that a restricted number of S. aureus clones circulate within the three herds at Toukounous and that their specific virulence-associated properties must still be further studied.
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Mastitis Bovina/epidemiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/patogenicidad , Agricultura , Animales , Técnicas de Tipificación Bacteriana/veterinaria , Bovinos , Línea Celular , Electroforesis en Gel de Campo Pulsado/veterinaria , Femenino , Mastitis Bovina/microbiología , Leche/microbiología , Niger/epidemiología , Reacción en Cadena de la Polimerasa/veterinaria , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , VirulenciaRESUMEN
BACKGROUND: Anaplasma phagocytophilum is a tick-borne pathogen of veterinary and human importance. Both ticks as vectors and vertebrates as reservoir hosts are essential for the cycle maintenance of this bacterium. Currently, the whole range of animal species reservoirs for A. phagocytophilum in natural environment is still unknown. Therefore, the aim of this study was to estimate the prevalence of infection with A. phagocytophilum in the wild boar population in southern Belgium. RESULTS: In the frame of a targeted surveillance program, 513 wild boars were sampled during the hunting season 2011. A nested 16S rRNA PCR was used to screen the presence of A. phagocytophilum DNA in spleen of boars. Within 513 samples, 5 (0,97%) were tested PCR positive and identification was confirmed by sequencing. CONCLUSIONS: This study gives the first insight of presence of A. phagocytophilum in wild boars in southern Belgium.
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Anaplasma phagocytophilum , Animales Salvajes/microbiología , Ehrlichiosis/veterinaria , Enfermedades de los Porcinos/microbiología , Anaplasma phagocytophilum/genética , Animales , Bélgica/epidemiología , Reservorios de Enfermedades/microbiología , Ehrlichiosis/epidemiología , Ehrlichiosis/microbiología , Femenino , Masculino , Reacción en Cadena de la Polimerasa/veterinaria , Prevalencia , ARN Ribosómico 16S/genética , Sus scrofa/microbiología , Porcinos , Enfermedades de los Porcinos/epidemiologíaRESUMEN
Staphylococcus aureus is recognized worldwide as a pathogen causing many serious diseases in humans and animals, and is one of the most important etiological agents of clinical and subclinical bovine mastitis. The aim of the present study was to investigate and correlate properties, that may be associated with persistent mastitis, of S. aureus strains isolated from milk of cows suffering from mastitis: (i) expression of capsular antigens (CP5 or CP8) by specific ELISA; (ii) intracellular survival by invasion of MAC-T cells; and (iii) biofilm production by spectrophotometry analysis after growth in TSBglc. The results showed that (i) the proportion of strains expressing capsular antigen was higher in cap8- than in cap5-positive isolates; (ii) a correlation was observed between the capsular profile and the intracellular survival as well as the biofilm production; and (iii) the capsular profile, biofilm production and intracellular survival were associated with only two agr-groups. Statistical and clustering analysis allowed us to establish different profiles that could be associated with in vivo persistence. Indeed, isolates belonging to agr group II, expressing the capsular antigen CP8 and showing low intracellular survival are probably better adapted to an extracellular niche. Conversely, isolates belonging to agr group I that do not express any capsular antigen (CP5 or CP8) but show high intracellular survival are probably better adapted to an intracellular niche.
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Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/fisiología , Animales , Antígenos Bacterianos/análisis , Cápsulas Bacterianas/clasificación , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/inmunología , Técnicas de Tipificación Bacteriana , Biopelículas/crecimiento & desarrollo , Bovinos , Línea Celular , Electroforesis en Gel de Campo Pulsado , Células Epiteliales/microbiología , Femenino , Glándulas Mamarias Animales/citología , Glándulas Mamarias Animales/microbiología , Leche/microbiología , Serotipificación , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/inmunología , Staphylococcus aureus/aislamiento & purificaciónRESUMEN
The aim of this study was to explore the presence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a collection of S. pseudintermedius strains isolated from dogs and cats with dermatitis in Japan and to compare their genotypic and phenotypic characteristics. Clonal relationships were determined by pulse field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing, and multilocus sequence typing (MLST). Biofilm formation assay was performed using safranin staining in microplates. Three virulence genes coding for S. intermedius exfoliative toxin and Panton-Valentine leukocidin (siet, lukS-PV and lukF-PV) were searched for in a collection of strains. Antimicrobial resistance against 15 antibiotics was studied by a disc diffusion method. Twenty-seven MRSP were isolated. According to PFGE results the isolates were not closely related except for a few strains. MLST showed that the strains belonged to five groups, ST71 and ST26 being the two most prevalent. Three types of SCCmec (II, II-III and V) were identified. All isolates were siet-positive but PVL-negative. Most strains (except for two) produced strong biofilm in tryptic soy broth with glucose. Seventy-eight percent of the isolates were resistant or intermediate to twelve or more antibiotics. Our study demonstrates that the ST71 lineage is widespread in Japan and that ST26 could represent an emerging lineage. Moreover, most of our strains are capable of forming strong biofilm and possess siet gene, two virulence characteristics that probably help the bacteria to persist and spread. Finally, our MRSP strains show a strong resistance profile to antibiotics commonly used in veterinary medicine.
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Resistencia a la Meticilina , Infecciones Estafilocócicas/veterinaria , Staphylococcus/clasificación , Staphylococcus/aislamiento & purificación , Animales , Antibacterianos/farmacología , Biopelículas/crecimiento & desarrollo , Gatos , Dermatoglifia del ADN , Perros , Electroforesis en Gel de Campo Pulsado , Japón , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Infecciones Estafilocócicas/microbiología , Staphylococcus/efectos de los fármacos , Staphylococcus/fisiología , Factores de Virulencia/genéticaRESUMEN
Discriminating Escherichia albertii from other Enterobacteriaceae is difficult. Systematic analyses showed that E. albertii represents a substantial portion of strains currently identified as eae-positive Escherichia coli and includes Shiga toxin 2f-producing strains. Because E. albertii possesses the eae gene, many strains might have been misidentified as enterohemorrhagic or enteropathogenic E. coli.
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Infecciones por Escherichia coli/microbiología , Escherichia/clasificación , Adhesinas Bacterianas/genética , Animales , Toxinas Bacterianas/genética , Aves/microbiología , Gatos , Escherichia/genética , Escherichia/aislamiento & purificación , Escherichia coli/clasificación , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/diagnóstico , Proteínas de Escherichia coli/genética , Humanos , Tipificación de Secuencias Multilocus , Fenotipo , Filogenia , Toxinas Shiga/genéticaRESUMEN
Enterohaemorrhagic Escherichia coli (EHEC) strains are responsible for food poisoning in humans in developed countries via consumption of vegetal and animal foodstuffs contaminated by ruminant feces. The clinical conditions caused by EHEC strains vary from undifferentiated diarrhea to hemorrhagic colitis with, in a few cases, the appearance of the hemolytic uremic syndrome, which can lead to death. Most EHEC strains can be found in the gut of healthy ruminants, but some of the strains, belonging to O26, O111, O118 serogroups, for example, are also responsible for digestive disorders in calves. The aim of this research was to study the genomic differences between two EHEC strains of serogroup O26 isolated from a young calf and a human with diarrhea, to identify specific sequences of the bovine strain that could be implicated in initial adherence or host specificity. No sequence implicated in host specificity was found during our study. Finally, several factors, not usually present in EHEC strains of serogroup O26, were identified in the bovine strain. One of them, the PAI I(CL3) locus initially presented as a marker for LEE-negative VTEC strains, was found in 11.3% of EPEC and EHEC strains.
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Hibridación Genómica Comparativa , Escherichia coli Enterohemorrágica/genética , Escherichia coli Enteropatógena/genética , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/veterinaria , Animales , Bovinos , Escherichia coli Enterohemorrágica/aislamiento & purificación , Especificidad del Huésped , Humanos , Factores de Virulencia/genéticaRESUMEN
BACKGROUND: Enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli are responsible for food poisoning (enteritis and enterotoxaemia) in humans in developed countries. Cattle are considered to be an important reservoir of EHEC and EPEC strains for humans. Moreover, some of the strains, belonging to the O26, O111, O118 serogroups, for example, are also responsible for digestive disorders in calves. The Translocated intimin receptor (Tir), the intimin (Eae) and the Tir-cytoskeleton coupling protein (TccP) represent three virulence factors implicated in the intimate attachment of the bacteria to the eukaryotic cell. Major variants have already been described for these genes among the different serogroups but minor variations have not often been studied. In this study, we examined the polymorphisms of the tir, eae and tccP2 genes of O26 strains (EPEC and EHEC isolated from bovines and from humans) with the aim to determine whether these polymorphisms are host specific or not. RESULTS: Of the 70 tested strains, 10 strains (14% of the strains) presented one or several polymorphisms in the tir and eae genes, which have never previously been described. Concerning tccP2 detection, 47 of the 70 strains (67% of the strains) were found to be positive for this gene. Most of the strains were found to possess tccP2 variants described in strains of serogroup O26. Nevertheless, three strains had tccP2 genes respectively described in strains of serogroup O111, O103 and O55. Moreover, none of the polymorphisms was statistically specific to the bovine or the human isolates. Nevertheless, the two major variants of tccP2 were statistically associated with the pathotype (EPEC or EHEC). CONCLUSIONS: In conclusion, tir and eae gene polymorphisms were found not to be numerous and not to be predominantly synonymous. Moreover, no difference was observed between human and bovine strains regarding the presence of polymorphisms. Finally, some tccP2 variants appeared to be pathotype specific. Further investigations need to be performed on a larger number of strains in order to confirm this specificity.
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Adhesinas Bacterianas/genética , Proteínas Portadoras/genética , Escherichia coli Enterohemorrágica/genética , Escherichia coli Enteropatógena/genética , Proteínas de Escherichia coli/genética , Polimorfismo Genético , Receptores de Superficie Celular/genética , Animales , Bovinos , ADN Bacteriano/química , ADN Bacteriano/genética , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/veterinaria , Humanos , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , Factores de Virulencia/genéticaRESUMEN
Cattle are considered to be an important reservoir of enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains that can cause disease in humans, and numerous studies of the prevalence of these strains in cattle (focusing mainly on dairy and beef cattle) have been carried out in different regions of Europe, Asia, and America. To date, only a few studies of veal calves have been published focusing on EHEC strains belonging to the O157 serogroup EHEC, whereas EHEC and VTEC can belong to hundreds of different serotypes (many of which are as dangerous to humans as the O157:H7 EHEC, such as strains of the O26, O91, O103, O111, O113 and O145 serogroups). The aim of this study was to investigate the presence of enteropathogenic Escherichia coli (EPEC), EHEC, and VTEC strains in veal calves in Belgium and to characterize the positive isolates (serogroups, virulence-associated factor-encoding genes and antibiotic resistance profiles). The prevalence of EPEC, EHEC, and VTEC strains in faecal samples from veal calves in Belgium was found to be 11.7% (6.5% of the calves were found to be positive for EPEC strains, 2.6% for EHEC, and 3.9% for VTEC strains). No O157:H7 EHEC Strain was identified, but three calves were found to carry strains belonging to the O26 and O111 serogroups. The results of antibiotic sensitivity tests showed a high level of resistance (83% of strains were resistant or intermediate resistant to five or more antibiotics of the 13 tested antibiotics), which might be caused by the frequent use of antibiotics in veterinary practice.
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Antibacterianos/farmacología , Enfermedades de los Bovinos/microbiología , Farmacorresistencia Bacteriana , Infecciones por Escherichia coli/veterinaria , Escherichia coli/efectos de los fármacos , Escherichia coli/patogenicidad , Animales , Animales Recién Nacidos , Técnicas de Tipificación Bacteriana/veterinaria , Bélgica/epidemiología , Bovinos , Enfermedades de los Bovinos/tratamiento farmacológico , Enfermedades de los Bovinos/epidemiología , Reservorios de Enfermedades/microbiología , Reservorios de Enfermedades/veterinaria , Escherichia coli Enterohemorrágica/efectos de los fármacos , Escherichia coli Enterohemorrágica/patogenicidad , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Pruebas de Sensibilidad Microbiana/veterinaria , Prevalencia , Escherichia coli Shiga-Toxigénica/efectos de los fármacos , Escherichia coli Shiga-Toxigénica/patogenicidadRESUMEN
Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains. The importance of this step in the infection resides in the fact that (1) adherence is the first contact between bacteria and intestinal cells without which the other steps cannot occur and (2) adherence is the basis of host specificity for a lot of pathogens. This review describes the initial adhesins of the EPEC, EHEC and VTEC strains. During the last few years, several new adhesins and putative colonisation factors have been described, especially in EHEC strains. Only a few adhesins (BfpA, AF/R1, AF/R2, Ral, F18 adhesins) appear to be host and pathotype specific. The others are found in more than one species and/or pathotype (EPEC, EHEC, VTEC). Initial adherence of EPEC, EHEC and VTEC strains to host cells is probably mediated by multiple mechanisms.
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Adhesión Bacteriana/fisiología , Escherichia coli Enterohemorrágica/fisiología , Escherichia coli Enteropatógena/fisiología , Intestinos/citología , Escherichia coli Shiga-Toxigénica/fisiología , AnimalesRESUMEN
Enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) inject a repertoire of effector proteins into host cells via a type III secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE). OspG is an effector protein initially identified in Shigella that was shown to inhibit the host innate immune response. In this study, we found ospG homologues in EHEC (mainly of serogroup O111) and in Yersinia enterocolitica. The T3SS encoded by the LEE was able to inject these different OspG homologues into host cells. Infection of HeLa cells with EHEC O111 inhibited the NF-kappaB-dependent innate immune response via a T3SS-dependent mechanism. However, an EHEC O111 ospG mutant was still able to inhibit NF-kappaB p65 transfer to the nucleus in infected cells stimulated by tumour necrosis factor alpha (TNF-alpha). In addition, no difference in the inflammatory response was observed between wild-type EHEC O111 and the isogenic ospG mutant in the rabbit ligated intestinal loop model. These results suggest that OspG is not the sole effector protein involved in the inactivation of the host innate immune system during EHEC O111 infection.
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Escherichia coli Enterohemorrágica/inmunología , Escherichia coli Enterohemorrágica/patogenicidad , Infecciones por Escherichia coli/inmunología , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/fisiología , Inmunidad Innata , FN-kappa B/antagonistas & inhibidores , Factores de Virulencia/fisiología , Secuencia de Aminoácidos , Animales , Escherichia coli Enteropatógena/inmunología , Escherichia coli Enteropatógena/patogenicidad , Infecciones por Escherichia coli/patología , Orden Génico , Células HeLa , Humanos , Intestinos/microbiología , Intestinos/patología , Datos de Secuencia Molecular , Conejos , Alineación de Secuencia , SerotipificaciónRESUMEN
Enterohemorrhagic Escherichia coli (EHEC) strains are responsible for food poisoning in developed countries via consumption of vegetal and animal food sources contaminated by ruminant feces, and some strains (O26, O111, and O118 serogroups) are also responsible for diarrhea in young calves. The prevalence of 27 putative adhesins of EHEC and of bovine necrotoxigenic E. coli (NTEC) was studied with a collection of 43 bovine and 29 human enteropathogenic (EPEC) and EHEC strains and 5 non-EPEC/non-EHEC (1 bovine and 4 human) O26 strains, using specific PCRs. Four "groups" of adhesins exist, including adhesins present in all O26 strains, adhesins present in most O26 strains, adhesins present in a few O26 strains, and adhesins not present in O26 strains. The common profile of EHEC/EPEC strains was characterized by the presence of loc3, loc5, loc7, loc11, loc14, paa, efa1, iha, lpfA(O26), and lpfA(O113) genes and the absence of loc1, loc2, loc6, loc12, loc13, saa, and eibG genes. Except for the lpfA(O26) gene, which was marginally associated with bovine EHEC/EPEC strains in comparison with human strains (P = 0.012), none of the results significantly differentiated bovine strains from human strains. One adhesin gene (ldaE) was statistically (P < 0.01) associated with O26 EHEC/EPEC strains isolated from diarrheic calves in comparison with strains isolated from healthy calves. ldaE-positive strains could therefore represent a subgroup possessing the specific property of producing diarrhea in young calves. This is the first time that the distribution of putative adhesins has been described for such a large collection of EHEC/EPEC O26 strains isolated from both humans and cattle.
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Adhesinas de Escherichia coli/genética , Enfermedades de los Bovinos/microbiología , Escherichia coli Enterohemorrágica/genética , Escherichia coli Enteropatógena/genética , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/veterinaria , Animales , Bovinos , ADN Bacteriano/genética , Escherichia coli Enterohemorrágica/aislamiento & purificación , Escherichia coli Enteropatógena/aislamiento & purificación , Humanos , Reacción en Cadena de la Polimerasa/métodos , Factores de Virulencia/genéticaRESUMEN
Vaccines used in control programmes of Bovine herpesvirus 1 (BoHV-1) utilize highly attenuated BoHV-1 strains marked by a deletion of the glycoprotein E (gE) gene. Since BoHV-1 recombinants are obtained at high frequency in experimentally coinfected cattle, the consequences of recombination on the virulence of gE-negative BoHV-1 were investigated. Thus, gE-negative BoHV-1 recombinants were generated in vitro from several virulent BoHV-1 and one mutant BoHV-1 deleted in the gC and gE genes. Four gE-negative recombinants were tested in the natural host. All the recombinants were more virulent than the gE-negative BoHV-1 vaccine and the gC- and gE-negative parental BoHV-1. The gE-negative recombinant isolated from a BoHV-1 field strain induced the highest severe clinical score. Latency and reactivation studies showed that three of the recombinants were reexcreted. Recombination can therefore restore virulence of gE-negative BoHV-1 by introducing the gE deletion into a different virulence background.