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1.
Vet Microbiol ; 239: 108479, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31767081

RESUMEN

Worldwide infections by Shiga toxin-producing Escherichia coli (STEC) in humans have been reported after consumption of mainly beef, but also deer meat. Not only the consumption of contaminated deer meat represents a risk, but also the transmission of STEC between deer and domestic animals should be considered. Within the framework of a telemetry study of roe deer (Capreolus capreolus) the aim was to analyse the occurrence of STEC. Due to the chance to sample some animals several times it was possible to obtain data on the repeated shedding of STEC in roe deer. In total 124 faeces or rectal swabs of 77 live trapped roe deer were collected. The isolates obtained were characterized for stx subtypes, different virulence genes, the so-called top-five serogroups, phylogenetic groups, PFGE-types and antimicrobial susceptibilities. The majority of roe deer were stx-positive whenever sampled. Twenty-eight animals were sampled more than once and were used to examine the duration of shedding STEC. The time interval of 6 persistently stx-negative tested animals was between 6 and 440d (median 49d, interquartile range (IQR) 17-258d). Ten animals excreted undistinguishable STEC strains in intervals between 4 and 778d (median 42d, IQR 22-79d). Most of the isolates were stx2b-positive, eae-negative and frequently ehlyA-positive. None of the isolates belonged to serogroup O26, O103, O111, O145 and O157, respectively. All isolates were sensitive to the antimicrobial substances tested. Although the duration of each shedding event could not be determined the results indicate long-term excretion of STEC in roe deer. This is an important consideration for the observance of good hygiene practice while field dressing of deer and preparing deer meat.


Asunto(s)
Ciervos , Infecciones por Escherichia coli/veterinaria , Escherichia coli Shiga-Toxigénica/fisiología , Animales , Antibacterianos/farmacología , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Pruebas de Sensibilidad Microbiana , Prevalencia , Recto/microbiología , Serogrupo , Escherichia coli Shiga-Toxigénica/clasificación , Escherichia coli Shiga-Toxigénica/efectos de los fármacos , Escherichia coli Shiga-Toxigénica/genética , Factores de Virulencia/genética
2.
Prev Vet Med ; 170: 104726, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31421496

RESUMEN

The increasing number of human cases infected with a highly virulent type of verotoxigenic Escherichia coli (VTEC) O157:H7 in Sweden is the result of domestic transmission originating in regional clusters of infected cattle farms. To control the spread of the bacteria a comprehensive picture of infection dynamics, routes of transmission between farms and risk factors for persistence is urgently needed. The aim of the study was to investigate different aspects of the epidemiology of VTEC O157:H7 on the Swedish island of Öland by combining information from environmental sampling of VTEC O157:H7 from 80 farms with information from farmer questionnaires, spatial and molecular analyses. The farms were sampled in the spring and fall of 2014 and on four of them additional samples were collected during summer and winter. The results show a high prevalence of VTEC O157:H7 and a high proportion of strains belonging to the virulent clade 8. Farms that became infected between samplings were all located in an area with high cattle density. The most important risk factors identified are generally associated with biosecurity and indicate that visitors travelling between farms may be important for transmission. In addition, whole genome sequencing of a subset of isolates from the four farms where additional sampling was performed revealed ongoing local transmission that cannot be observed with a lower resolution typing method. Our observations also show that VTEC O157:H7 may persist in the farm environment for extended periods of time, suggesting that specific on-farm measures to reduce environmental prevalence and spread between groups of animals may be required in these cases.


Asunto(s)
Enfermedades de los Bovinos/epidemiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli Shiga-Toxigénica/fisiología , Animales , Bovinos , Infecciones por Escherichia coli/epidemiología , Granjas/estadística & datos numéricos , Prevalencia , Factores de Riesgo , Estaciones del Año , Suecia/epidemiología
3.
Artículo en Inglés | MEDLINE | ID: mdl-31083597

RESUMEN

Shiga toxin-producing Escherichia Coli (STEC) infections routinely run as a common gastroenteritis, but in many cases they may evolve towards hemolytic uremic syndrome (HUS). HUS is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Gut microorganisms have a fundamental impact on human physiology, because they modulate normal intestinal functions and play a pivotal role in influencing the local and systemic immune responses. Despite surveillance established in many countries and major progresses in the understanding of STEC-HUS mechanisms, no specific treatment is currently available. Targeting the gut microbiota could represent a new potential therapeutic strategy in STEC infection. In this paper, we reviewed the current knowledge about microbiota characteristics of patients with STEC infections, as well as in vitro and in vivo evidence of probiotic supplementation in managing STEC gastroenteritis and in HUS onset prevention.


Asunto(s)
Infecciones por Escherichia coli/tratamiento farmacológico , Gastroenteritis/tratamiento farmacológico , Microbioma Gastrointestinal , Síndrome Hemolítico-Urémico/tratamiento farmacológico , Probióticos/uso terapéutico , Escherichia coli Shiga-Toxigénica/fisiología , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Gastroenteritis/complicaciones , Gastroenteritis/epidemiología , Gastroenteritis/microbiología , Síndrome Hemolítico-Urémico/epidemiología , Síndrome Hemolítico-Urémico/microbiología , Humanos , Incidencia
4.
Food Microbiol ; 82: 482-488, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31027809

RESUMEN

Shiga toxin-producing Escherichia coli (STEC) is one of the most common causal agents of foodborne illness linked to fresh leafy vegetables. Here, we investigated the impact of spinach-associated microorganisms on proliferation and biofilm formation of STEC O157:H7 on stainless steel surfaces at temperatures related to produce production and postharvest processing environments. Although a proliferation of inoculated pathogen cells in spinach leaf wash water was detected at all temperatures examined, the impact of spinach-associated microorganisms on the proliferation of E. coli O157:H7 was observed at 10 °C and 26 °C, but not at 4 °C. The inhibition of E. coli O157:H7 growth by spinach-associated microorganisms indicated a competition between the pathogen and spinach indigenous microflora. A significant decrease of the pathogen population in mixed biofilms was observed only at 26 °C for curli-deficient strain MQC43, but not for curli-expressing strain MQC57. Deletion of curli genes in a curli-expressing strain resulted in a phenotype similar to that of MQC43 in mixed biofilms; however, this deficiency was rescued when curli biogenesis was restored in the curli-deletion mutant strain. Our data support that curli confer E. coli O157:H7 a competitive trait in mixed biofilms, presumably through the interaction between STEC and the biofilm-proficient microorganisms associated with spinach leaves.


Asunto(s)
Biopelículas , Proteínas de Escherichia coli/fisiología , Microbiología de Alimentos , Escherichia coli Shiga-Toxigénica/fisiología , Spinacia oleracea/microbiología , Adhesión Bacteriana/genética , Biopelículas/crecimiento & desarrollo , Recuento de Colonia Microbiana , Escherichia coli O157/genética , Escherichia coli O157/crecimiento & desarrollo , Escherichia coli O157/fisiología , Proteínas de Escherichia coli/genética , Prueba de Complementación Genética , Interacciones Microbianas , Microbiota/fisiología , Mutación , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/crecimiento & desarrollo , Acero Inoxidable , Temperatura
5.
Environ Res ; 172: 630-636, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30878734

RESUMEN

The microbial quality of irrigation water has increasingly become a concern as a source of contamination for fruits and vegetables. Non-traditional sources of water are being used by more and more growers in smaller, highly diversified farms in the Mid-Atlantic region of the U.S. Shiga-toxigenic E. coli (STEC) have been responsible for several outbreaks of infections associated with the consumption of leafy greens. Our study evaluated the prevalence of the "big seven" STEC serogroups and the associated enterohemorrhagic E. coli (EHEC) virulence factors (VF) genes in conventional and nontraditional irrigation waters in the Mid-Atlantic region of the U.S. Water samples (n = 510) from 170 sampling events were collected from eight untreated surface water sites, two wastewater reclamation facilities, and one vegetable processing plant, over a 12-month period. Ten liters of water were filtered through Modified Moore swabs (MMS); swabs were then enriched into Universal Pre-enrichment Broth (UPB), followed by enrichment into non-O157 STEC R&F broth and isolation on R & F non-O157 STEC chromogenic plating medium. Isolates (n = 2489) from enriched MMS from water samples were screened for frequently reported STEC serogroups that cause foodborne illness: O26, O45, O103, O111, O121, O145, and O157, along with VF genes stx1, stx2, eae, and ehxA. Through this screening process, STEC isolates were found in 2.35% (12/510) of water samples, while 9.0% (46/510) contained an atypical enteropathogenic E. coli (aEPEC) isolate. The eae gene (n = 88 isolates) was the most frequently detected EHEC VF of the isolates screened. The majority of STEC isolates (stx1 or stx2) genes mainly came from either a pond or reclamation pond water site on two specific dates, potentially indicating that these isolates were not spatially or temporally distributed among the sampling sites. STEC isolates at reclaimed water sites may have been introduced after wastewater treatment. None of the isolates containing eae were determined to be Escherichia albertii. Our work showed that STEC prevalence in Mid-Atlantic untreated surface waters over a 12-month period was lower than the prevalence of atypical EPEC.


Asunto(s)
Riego Agrícola , Escherichia coli Enteropatógena , Proteínas de Escherichia coli , Escherichia coli Shiga-Toxigénica , Microbiología del Agua , Riego Agrícola/estadística & datos numéricos , Carga Bacteriana , Escherichia coli Enteropatógena/fisiología , Heces/microbiología , Mid-Atlantic Region , Prevalencia , Escherichia coli Shiga-Toxigénica/fisiología
6.
Int J Food Microbiol ; 289: 57-63, 2019 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-30199736

RESUMEN

Several outbreaks of illness have been associated with consumption of alfalfa sprouts contaminated with Shiga toxin-producing Escherichia coli (STEC) and Salmonella. The ozone application was investigated as an intervention. Alfalfa seeds were inoculated with cocktails of 3 Salmonella strains, including serotypes Typhimurium, Agona and Saintpaul, and 3 strains of Shiga toxin-producing Escherichia coli (STEC) including serotypes O104:H4, O157:H7 and O121:H19 with a final load of 7.0 log CFU/ml. Then, the inoculated seeds, and the sprouts obtained from these seeds were separately subjected to aqueous ozone treatment containing (5 mg/L) ozone for varied times of exposure. The mean log reductions for Salmonella achieved on seeds after 10, 15, and 20 min of ozone exposure were 1.6 ±â€¯0.5, 1.7 ±â€¯0.3, 2.1 ±â€¯0.5, respectively and 1.5 ±â€¯0.4, 1.6 ±â€¯0.4, 2.1 ±â€¯0.5 for STEC, respectively. For sprouts obtained from the inoculated seed, the mean log reductions for Salmonella after 10, 15, and 20 min exposure times were 0.7 ±â€¯0.2, 1.1 ±â€¯0.4, 3.6 ±â€¯0.2, respectively, whereas the mean log reductions for STEC were 0.7 ±â€¯0.1, 1.2 ±â€¯0.3 and 1.8 ±â€¯0.2, respectively. At each contact time, there were no differences in log reductions between pathogens on seeds (P > 0.05), whereas on sprouts, the reductions obtained at 20 min were significantly greater (P < 0.05) for Salmonella than for STEC. On both seeds and sprouts, the exposure time had significant (P < 0.05) effects on log reductions of Salmonella and STEC. The weight, color properties and shelf life of ozonated sprouts were also tested. The ozonation did not have negative effects on germination (%), color and mass of sprouts in comparison with the controls. This study confirmed that it is possible to substantially reduce Salmonella and STEC by using a low ozone concentration (5 mg/L) and reduce food safety risk with less concern about the safety for processing workers of this treatment, this without affecting seed germination. This procedure may be a promising intervention to reduce Salmonella and STEC from alfalfa seeds and sprouts.


Asunto(s)
Microbiología de Alimentos/métodos , Medicago sativa/microbiología , Ozono/farmacología , Salmonella/efectos de los fármacos , Plantones/microbiología , Semillas/microbiología , Escherichia coli Shiga-Toxigénica/efectos de los fármacos , Recuento de Colonia Microbiana , Humanos , Salmonella/fisiología , Escherichia coli Shiga-Toxigénica/fisiología
7.
Food Microbiol ; 76: 434-442, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30166171

RESUMEN

Phages are potentially useful as antimicrobial agents in food, especially cocktails of different phages which may prevent the development of bacterial resistance. Biocontrol assays with a six-phage cocktail, which is lytic against DH5α, an enteropathogenic (EPEC) and two Shiga-toxigenic (STEC) Escherichia coli strains, were performed in Hershey-Mg broth, milk and meat at refrigerated (4 °C), room (24 °C) and abusive (37 °C) temperatures. At 4 °C, cell counts were significantly lower (2.2-2.8 log10 CFU/mL) when E. coli strains (∼109 CFU/mL) were challenged against the phage cocktail (∼109 PFU/mL) in Hershey-Mg broth after 24 h. However, reductions were higher (3.2-3.4 log10 CFU/mL) after a 48 h exposure for all the strains tested. In addition, reduction values reached up to 3.4 log10 CFU/mL (24 °C) and 3.6 log10 CFU/mL (37 °C) in challenge tests after 24 h, though the reductions achieved were slightly lower after 48 h for the four E. coli strains tested. In milk, the cocktail was highly effective since bacterial counts were below the detection limit (<101 CFU/mL) at 4 °C, while the reductions ranged from 2 to 4 log10 CFU/mL at 24 °C after a 24 h exposure. At 37 °C, DH5α was eliminated within 2 h, and an average cell decrease of 4 log10 CFU/mL was observed for the three pathogenic strains tested. When the assays were performed in meat, biocontrol values ranged from 0.5 to 1.0 log10 CFU/mL after 48 h at 4 °C, while a higher cell inactivation was achieved at 24 °C (2.6-4.0 log10 CFU/mL) and 37 °C (3.0-3.8 log10 CFU/mL). Furthermore, higher inactivation values for O157:H7 STEC (1.55 ±â€¯0.35 log10 CFU/mL) at 4 °C were obtained in meat when incubation was extended up to 6 days. As a conclusion, our six-phage cocktail was highly effective at 24 °C and 37 °C, though less effective at 4 °C in both food matrices evaluated. Thus, it might be applied against pathogenic EPEC and STEC strains to prevent foodborne diseases especially when the cold chain is lost.


Asunto(s)
Bacteriófagos/fisiología , Conservación de Alimentos/métodos , Carne/microbiología , Leche/microbiología , Escherichia coli Shiga-Toxigénica/virología , Animales , Bacteriófagos/clasificación , Bacteriófagos/genética , Bacteriófagos/aislamiento & purificación , Bovinos , Escherichia coli Shiga-Toxigénica/fisiología , Temperatura
8.
PLoS One ; 13(7): e0199968, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29965972

RESUMEN

OBJECTIVE: Since 1987 all fecal samples referred to the clinical microbiology laboratory of the UZ Brussel were screened for the presence of Shiga toxin-producing E. coli (STEC). In this study all STEC strains isolated over a period of 27 years (1987-2014) were reexamined to achieve deeper insight in the STEC infections in our patient population. METHODS: A total of 606 STEC strains from 604 patients were subjected to molecular methods for shiga toxin (stx) subtyping, detection of additional virulence genes, typing of the O-serogroups, and phylogenetic relatedness assessment of STEC O157:H7/H-. RESULTS: Since the introduction of PCR in 1991 the annual positivity rates varied between 1.1% and 2.7%. The isolation rate of STEC O157:H7/H- remained stable over the years while the isolation rate of non-O157 serotypes increased, mainly since 2011. The majority of the patients were children. Uncomplicated- and bloody diarrhea were the most prevalent gastrointestinal manifestations (respectively 51.9% and 13.6%), 4.3% of the strains were related to the hemolytic uremic syndrome (HUS), and 30.2% of the patients showed none of these symptoms. The strains were very diverse; they belonged to 72 different O-serovars and all stx subtypes except stx1d and stx2g were identified. Out of the 23 stx2f-positives one was associated with HUS and one belonged to the E. albertii species. As seen in other studies, the frequency of strains of the O157:H7/H- serotype and strains carrying stx2a, eaeA and ehxA was higher in patients with HUS. CONCLUSIONS: The characteristics and trends of STEC infection seen in our patient population are similar to those noted in other countries. STEC infections in our hospital are mainly sporadic, and a substantial portion of the patients were asymptomatic carriers. Human STEC Stx2f infection was less rare than previously assumed and we report the first Belgian STEC stx2f HUS case and stx2f positive E. albertii infection.


Asunto(s)
Hospitales Universitarios , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bélgica , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Filogenia , Serotipificación , Escherichia coli Shiga-Toxigénica/clasificación , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/fisiología , Virulencia , Adulto Joven
9.
J Microbiol Biotechnol ; 28(9): 1413-1425, 2018 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-29926707

RESUMEN

Shiga toxins (Stxs) are the main virulence factors expressed by the pathogenic Stx-producing bacteria, namely, Shigella dysenteriae serotype 1 and certain Escherichia coli strains. These bacteria cause widespread outbreaks of bloody diarrhea (hemorrhagic colitis) that in severe cases can progress to life-threatening systemic complications, including hemolytic uremic syndrome (HUS) characterized by the acute onset of microangiopathic hemolytic anemia and kidney dysfunction. Shiga toxicosis has a distinct pathogenesis and animal models of Stx-associated HUS have allowed us to investigate this. Since these models will also be useful for developing effective countermeasures to Stx-associated HUS, it is important to have clinically relevant animal models of this disease. Multiple studies over the last few decades have shown that mice injected with purified Stxs develop some of the pathophysiological features seen in HUS patients infected with the Stx-producing bacteria. These features are also efficiently recapitulated in a non-human primate model (baboons). In addition, rats, calves, chicks, piglets, and rabbits have been used as models to study symptoms of HUS that are characteristic of each animal. These models have been very useful for testing hypotheses about how Stx induces HUS and its neurological sequelae. In this review, we describe in detail the current knowledge about the most well-studied in vivo models of Stx-induced HUS; namely, those in mice, piglets, non-human primates, and rabbits. The aim of this review is to show how each human clinical outcome-mimicking animal model can serve as an experimental tool to promote our understanding of Stx-induced pathogenesis.


Asunto(s)
Modelos Animales de Enfermedad , Síndrome Hemolítico-Urémico/microbiología , Toxinas Shiga/toxicidad , Shigella dysenteriae/fisiología , Animales , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/patología , Síndrome Hemolítico-Urémico/patología , Síndrome Hemolítico-Urémico/fisiopatología , Humanos , Toxinas Shiga/clasificación , Escherichia coli Shiga-Toxigénica/química , Escherichia coli Shiga-Toxigénica/patogenicidad , Escherichia coli Shiga-Toxigénica/fisiología , Shigella dysenteriae/química , Shigella dysenteriae/patogenicidad , Factores de Virulencia/clasificación , Factores de Virulencia/toxicidad
10.
Vet Res ; 49(1): 28, 2018 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-29514704

RESUMEN

The principal virulence factor of Shiga toxin (Stx)-producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. We examined whether immunization with genetically inactivated recombinant Shiga toxoids (rStx1MUT/rStx2MUT) influences STEC shedding in a calf cohort. A group of 24 calves was passively (colostrum from immunized cows) and actively (intra-muscularly at 5th and 8th week) vaccinated. Twenty-four calves served as unvaccinated controls (fed with low anti-Stx colostrum, placebo injected). Each group was divided according to the vitamin E concentration they received by milk replacer (moderate and high supplemented). The effective transfer of Stx-neutralizing antibodies from dams to calves via colostrum was confirmed by Vero cell assay. Serum antibody titers in calves differed significantly between the vaccinated and the control group until the 16th week of life. Using the expression of activation marker CD25 on CD4+CD45RO+ cells and CD8αhiCD45RO+ cells as flow cytometry based read-out, cells from vaccinated animals responded more pronounced than those of control calves to lysates of STEC and E. coli strains isolated from the farm as well as to rStx2MUT in the 16th week. Summarized for the entire observation period, less fecal samples from vaccinated calves were stx1 and/or stx2 positive than samples from control animals when calves were fed a moderate amount of vitamin E. This study provides first evidence, that transfer to and induction in young calves of Stx-neutralizing antibodies by Shiga toxoid vaccination offers the opportunity to reduce the incidence of stx-positive fecal samples in a calf cohort.


Asunto(s)
Derrame de Bacterias/inmunología , Vacunas Bacterianas/inmunología , Enfermedades de los Bovinos/prevención & control , Inmunización Pasiva/veterinaria , Escherichia coli Shiga-Toxigénica/fisiología , Toxoides/inmunología , Vacunación/veterinaria , Alimentación Animal/análisis , Animales , Bovinos , Enfermedades de los Bovinos/inmunología , Estudios de Cohortes , Calostro/inmunología , Dieta/veterinaria , Suplementos Dietéticos/análisis , Infecciones por Escherichia coli/inmunología , Infecciones por Escherichia coli/prevención & control , Infecciones por Escherichia coli/veterinaria , Inmunidad Materno-Adquirida/inmunología , Inyecciones Intramusculares/veterinaria , Masculino , Vacunas Sintéticas/administración & dosificación
11.
Artículo en Inglés | MEDLINE | ID: mdl-29450193

RESUMEN

Most bacterial infections initiate at the mucosal epithelium lining the gastrointestinal, respiratory, and urogenital tracts. At these sites, bacterial pathogens must adhere and increase in numbers to effectively breach the outer barrier and invade the host. If the bacterium succeeds in reaching the bloodstream, effective dissemination again requires that bacteria in the blood, reestablish contact to distant endothelium sites and form secondary site foci. The infectious potential of bacteria is therefore closely linked to their ability to adhere to, colonize, and invade epithelial and endothelial surfaces. Measurement of bacterial adhesion to epithelial cells is therefore standard procedure in studies of bacterial virulence. Traditionally, such measurements have been conducted with microtiter plate cell cultures to which bacteria are added, followed by washing procedures and final quantification of retained bacteria by agar plating. This approach is fast and straightforward, but yields only a rough estimate of the adhesive properties of the bacteria upon contact, and little information on the ability of the bacterium to colonize these surfaces under relevant physiological conditions. Here, we present a method in which epithelia/endothelia are simulated by flow chamber-grown human cell layers, and infection is induced by seeding of pathogenic bacteria on these surfaces under conditions that simulate the physiological microenvironment. Quantification of bacterial adhesion and colonization of the cell layers is then performed by in situ time-lapse fluorescence microscopy and automatic detection of bacterial surface coverage. The method is demonstrated in three different infection models, simulating Staphylococcus aureus endothelial infection and Escherichia coli intestinal- and uroepithelial infection. The approach yields valuable information on the fitness of the bacterium to successfully adhere to and colonize epithelial surfaces and can be used to evaluate the influence of specific virulence genes, growth conditions, and antimicrobial treatment on this process.


Asunto(s)
Infecciones Bacterianas/microbiología , Carga Bacteriana/métodos , Fenómenos Fisiológicos Bacterianos , Membrana Mucosa/microbiología , Adhesión Bacteriana , Células Cultivadas , Células Epiteliales/microbiología , Tracto Gastrointestinal/microbiología , Humanos , Modelos Teóricos , Escherichia coli Shiga-Toxigénica/fisiología , Staphylococcus aureus/fisiología
12.
Appl Environ Microbiol ; 84(1)2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29054868

RESUMEN

Cah is a calcium-binding autotransporter protein involved in autoaggregation and biofilm formation. Although cah is widespread in Shiga toxin-producing Escherichia coli (STEC), we detected mutations in cah at a frequency of 31.3% in this pathogen. In STEC O157:H7 supershedder strain SS17, a large deletion results in a smaller coding sequence, encoding a protein lacking the C-terminal 71 amino acids compared with Cah in STEC O157:H7 strain EDL933. We examined the function of Cah in biofilm formation and host colonization to better understand the selective pressures for cah mutations. EDL933-Cah played a conditional role in biofilm formation in vitro: it enhanced E. coli DH5α biofilm formation on glass surfaces under agitated culture conditions that prevented autoaggregation but inhibited biofilm formation under hydrostatic conditions that facilitated autoaggregation. This function appeared to be strain dependent since Cah-mediated biofilm formation was diminished when an EDL933 cah gene was expressed in SS17. Deletion of cah in EDL933 enhanced bacterial attachment to spinach leaves and altered the adherence pattern of EDL933 to bovine recto-anal junction squamous epithelial (RSE) cells. In contrast, in trans expression of EDL933 cah in SS17 increased its attachment to leaf surfaces, and in DH5α, it enhanced its adherence to RSE cells. Hence, the ecological function of Cah appears to be modulated by environmental conditions and other bacterial strain-specific properties. Considering the prevalence of cah in STEC and its role in attachment and biofilm formation, cah mutations might be selected in ecological niches in which inactivation of Cah would result in an increased fitness in STEC during colonization of plants or animal hosts.IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) harbors genes encoding diverse adhesins, and many of these are known to play an important role in bacterial attachment and host colonization. We demonstrated here that the autotransporter protein Cah confers on E. coli DH5α cells a strong autoaggregative phenotype that is inversely correlated with its ability to form biofilms and plays a strain-specific role in plant and animal colonization by STEC. Although cah is widespread in the STEC population, we detected a mutation rate of 31.3% in cah, which is similar to that reported for rpoS and fimH The formation of cell aggregates due to increased bacterium-to-bacterium interactions may be disadvantageous to bacterial populations under conditions that favor a planktonic state in STEC. Therefore, a loss-of-function mutation in cah is likely a selective trait in STEC when autoaggregative properties become detrimental to bacterial cells and may contribute to the adaptability of STEC to fluctuating environments.


Asunto(s)
Proteínas de Escherichia coli/genética , Mutación , Escherichia coli Shiga-Toxigénica/fisiología , Canal Anal/microbiología , Animales , Bovinos , Células Epiteliales/microbiología , Proteínas de Escherichia coli/metabolismo , Hojas de la Planta/microbiología , Recto/microbiología , Escherichia coli Shiga-Toxigénica/genética , Spinacia oleracea/microbiología
13.
Vet Microbiol ; 208: 8-17, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28888654

RESUMEN

PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. OBJECTIVE: Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. METHODS AND RESULTS: The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpfO113. E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 108 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. CONCLUSIONS: These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment.


Asunto(s)
Adhesión Bacteriana/fisiología , Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli Shiga-Toxigénica/fisiología , Animales , Antibacterianos/farmacología , Biopelículas , Bovinos , Farmacorresistencia Bacteriana , Infecciones por Escherichia coli/microbiología , Escherichia coli O157 , Femenino , Regulación Bacteriana de la Expresión Génica , Masculino , Ratones , Ratones Endogámicos BALB C , Escherichia coli Shiga-Toxigénica/genética , Células Vero , Virulencia , Factores de Virulencia/genética , Factores de Virulencia/metabolismo
14.
Br Poult Sci ; 58(6): 664-672, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28881144

RESUMEN

1. Escherichia coli is one of the most common facultative anaerobic species present in the gastrointestinal tract of animals and human beings. Usually they occur as commensals, but some serotypes can cause significant illnesses in humans as well as mammals and birds. 2. The occurrence of E. coli in different categories of table eggs collected from markets was evaluated. Isolates were analysed for the presence of virulence genes, antibiotic susceptibility pattern and efficacy of peracetic acid and chlorine for the purpose of decontaminating table eggs. 3. Significant differences were observed in the occurrence of E. coli between different groups viz. processed (cleaned, washed, sanitised and packed eggs), unprocessed (un-cleaned, un-sanitised and loose eggs) and free range (eggs obtained from backyard poultry) table eggs. Overall, E. coli occurred in table eggs at 28.6% with 22.9, 29.2 and 50.0% occurrence in processed, unprocessed and free-range table eggs, respectively. 4. A total of 24 isolates of E. coli were obtained and screened for virulence genes viz. STH, SLT1/2 and INVE genes. Of the 24 isolates recovered, 10 typeable isolates belonged to O141, O119, O9, O120 and O101 serotypes, while the remaining 14 were untypeable. Antibiograms of the isolates showed multiple antimicrobial resistance (MAR) index in the range of 0.13-0.40. 5. Peracetic acid (PAA) and chlorine (CL) were studied for their sanitisation efficacy; concentrations of 100 mg/kg of PAA and 200 mg/kg of CL completely inactivated E. coli over the egg surface and also resulted in 2.58 and 2.38 log reduction in total viable counts (TVC), respectively. 6. The presence of virulence-associated shiga-like toxin (SLT1/2) and invasion E (INVE) genes and antimicrobial resistance among the emerging serotypes of pathogenic E. coli isolated from table eggs has public health implications. It underscores the need to implement better management practices across the production systems and marketing channels to produce E. coli-free wholesome eggs for consumers.


Asunto(s)
Pollos , Desinfectantes/farmacología , Huevos/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli/fisiología , Escherichia coli/patogenicidad , Enfermedades de las Aves de Corral , Animales , Cloro/farmacología , Farmacorresistencia Bacteriana , Escherichia coli Enterotoxigénica/efectos de los fármacos , Escherichia coli Enterotoxigénica/genética , Escherichia coli Enterotoxigénica/patogenicidad , Escherichia coli Enterotoxigénica/fisiología , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/prevención & control , Ácido Peracético/farmacología , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/prevención & control , Serotipificación , Escherichia coli Shiga-Toxigénica/efectos de los fármacos , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/patogenicidad , Escherichia coli Shiga-Toxigénica/fisiología , Virulencia/genética
15.
Epidemiol Infect ; 145(14): 2998-3006, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28925349

RESUMEN

Shiga toxin-producing Escherichia coli (STEC) is a significant cause of gastrointestinal infection and the haemolytic-uremic syndrome (HUS). STEC outbreaks are commonly associated with food but animal contact is increasingly being implicated in its transmission. We report an outbreak of STEC affecting young infants at a nursery in a rural community (three HUS cases, one definite case, one probable case, three possible cases and five carriers, based on the combination of clinical, epidemiological and laboratory data) identified using culture-based and molecular techniques. The investigation identified repeated animal contact (animal farming and petting) as a likely source of STEC introduction followed by horizontal transmission. Whole genome sequencing (WGS) was used for real-time investigation of the incident and revealed a unique strain of STEC O26:H11 carrying stx2a and intimin. Following a public health intervention, no additional cases have occurred. This is the first STEC outbreak reported from Israel. WGS proved as a useful tool for rapid laboratory characterization and typing of the outbreak strain and informed the public health response at an early stage of this unusual outbreak.


Asunto(s)
Brotes de Enfermedades , Infecciones por Escherichia coli/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Escherichia coli Shiga-Toxigénica/fisiología , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Genómica , Síndrome Hemolítico-Urémico/microbiología , Humanos , Lactante , Israel/epidemiología , Filogenia , Salud Pública , Análisis de Secuencia de ADN , Escherichia coli Shiga-Toxigénica/genética
16.
Epidemiol Infect ; 145(8): 1577-1583, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28241895

RESUMEN

Verotoxin-producing Escherichia coli (VTEC) is a significant problem in the under-six population in the Midlands, Ireland. VTEC spreads by person-to-person transmission and children attending childcare facilities are excluded until they achieve two consecutive negative stool samples. This report analyses 10 years data on the number of days children under the age of six take to microbiologically clear VTEC. We identified from our data that the median clearance time for VTEC was 39 days, interquartile range (IQR) 27-56 days, maximum clearance time 283 days. At 70 days from onset of infection, 90% of children had cleared the infection. These findings were slightly more prolonged but consistent with international literature on VTEC clearance times for children. Asymptomatic children cleared VTEC infection significantly faster (median time 25 days IQR 13-43 days) than symptomatic children (median time 43 days IQR 31-58 days). Symptomatic children older than 1 year of age cleared VTEC infection significantly faster (median time 42 days IQR 31-57) than symptomatic children year under 1 year (median time 56 days IQR 35-74 days). This report identifies clear data which can be used to more accurately advise parents on time periods required to achieve microbiological clearance from VTEC.


Asunto(s)
Derrame de Bacterias , Infecciones por Escherichia coli/microbiología , Escherichia coli Shiga-Toxigénica/fisiología , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Irlanda , Masculino
17.
Epidemiol Infect ; 145(8): 1557-1566, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28260536

RESUMEN

A nationwide study of Shiga toxin-producing Escherichia coli (STEC) was performed to determine the prevalence, characteristics and risk factors for fecal shedding of STEC among cattle in Japan. Information on rearing practices was also collected to identify risk factors for fecal shedding of STEC. STEC was isolated from 24·1% of samples (133/551) collected from 59·1% of farms (65/110). Bayesian clustering using the virulence marker profiles of the isolates subdivided the isolates into four genetically distinct groups, two of which corresponded to eae- or saa-positive STEC, which can cause severe disease in human. Both STEC groups exhibited characteristic phylogeny and virulence marker profiles. It is noteworthy that the tellurite resistance gene was not detected in all saa-positive STEC isolates, suggesting that the standard isolation method using tellurite might lead to an underestimation of the prevalence of saa-positive STEC. A multivariate logistic regression model using epidemiological information revealed a significantly (P < 0·01) high odds ratio on STEC fecal shedding in tie-stall housing and a low odds ratio in flat feed box and mechanical ventilation. Information on isolate characteristics of the two major pathotypes and risk factors in rearing practices will facilitate the development of preventative measures for STEC fecal shedding from cattle.


Asunto(s)
Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli Shiga-Toxigénica/fisiología , Escherichia coli Shiga-Toxigénica/patogenicidad , Factores de Virulencia/aislamiento & purificación , Crianza de Animales Domésticos/normas , Animales , Derrame de Bacterias , Teorema de Bayes , Bovinos , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Femenino , Japón/epidemiología , Masculino , Filogenia , Prevalencia , Factores de Riesgo , Escherichia coli Shiga-Toxigénica/genética
18.
Vet Microbiol ; 202: 64-71, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28161211

RESUMEN

F4+E. coli and F18+E. coli infections are an important threat for pig industry worldwide. Antibiotics are commonly used to treat infected piglets, but the emerging development of resistance against antibiotics raises major concerns. Hence, alternative therapies to prevent pigs from F4+E. coli and F18+E. coli infections need to be developed. Since cranberry previously showed anti-adhesive activity against uropathogenic E. coli, we aimed to investigate whether cranberry extract could also inhibit binding of F4+E. coli and F18+E. coli to pig intestinal epithelium. Using the in vitro villus adhesion assay, we found that low concentrations of cranberry extract (20µg or 100µg/ml) have strong inhibitory activity on F4+E. coli (75.3%, S.D.=9.31 or 95.8%, S.D.=2.56, respectively) and F18+E. coli adherence (100% inhibition). This effect was not due to antimicrobial activity. Moreover, cranberry extract (10mg or 100mg) could also abolish in vivo binding of F4 and F18 fimbriae to the pig intestinal epithelium in ligated loop experiments. Finally, two challenge experiments with F18+E. coli were performed to address the efficacy of in-feed or water supplemented cranberry extract. No effect could be observed in piglets that received cranberry extract only in feed (1g/kg or 10g/kg). However, supplementation of feed (10g/kg) and drinking water (1g/L) significantly decreased excretion and diarrhea. The decreased infection resulted in a decreased serum antibody response indicating reduced exposure to F18+E. coli.


Asunto(s)
Adhesión Bacteriana/efectos de los fármacos , Proteínas de Escherichia coli/metabolismo , Extractos Vegetales/farmacología , Escherichia coli Shiga-Toxigénica/fisiología , Enfermedades de los Porcinos/microbiología , Vaccinium macrocarpon/química , Animales , Diarrea/microbiología , Diarrea/prevención & control , Diarrea/veterinaria , Proteínas de Escherichia coli/genética , Proteínas Fimbrias/genética , Proteínas Fimbrias/metabolismo , Regulación Bacteriana de la Expresión Génica , Mucosa Intestinal/microbiología , Extractos Vegetales/química , Escherichia coli Shiga-Toxigénica/genética , Porcinos
19.
J Appl Microbiol ; 122(4): 1101-1109, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28150898

RESUMEN

AIMS: Although Shiga toxins (Stx) are well-established virulence traits of O113:H21 Shigatoxigenic Escherichia coli (STEC) strains, a shortage in the knowledge of other virulence properties that may contribute to pathogenesis may exist in this serotype. This study investigated biofilm, invasiveness and colicinogeny capabilities in O113:H21 STEC isolated in Brazil, mostly from animal reservoirs. A search for genes that were reported to participate in the process of biofilm formation was also performed. METHODS AND RESULTS: The 34 O113:H21 STEC isolates analysed were assayed for biofilm production in polystyrene microplates. Genes for biofilm were investigated by PCR. Invasion of cell lineages was assessed in gentamicin protection assays and colicinogeny was investigated by phenotypic tests. Fifty per cent of the strains were biofilm formers, and 35% exhibited an invasive behaviour. The pattern of distribution of biofilm-related genes did not correlate with biofilm phenotypes observed, and a high percentage of the investigated strains were able to secrete colicins. CONCLUSION: Ability to form biofilm, invasiveness and colicinogeny is demonstrated for the first time in a collection of O113:H21 STEC. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability to express three additional phenotypes besides Stx production may be a factor influencing the pathogenicity and persistence potential of O113:H21 STEC.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Escherichia coli Shiga-Toxigénica/patogenicidad , Animales , Células CACO-2 , Línea Celular , Colicinas/metabolismo , Humanos , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Escherichia coli Shiga-Toxigénica/fisiología , Virulencia
20.
FEMS Microbiol Lett ; 364(2)2017 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-28011696

RESUMEN

Shiga toxin-producing Escherichia coli (STEC) are recognized as one of the most dangerous foodborne pathogens. The production of Shiga toxins together with intimin protein is among the main virulence factors. However, the ability to form biofilm can protect bacteria against environmental factors (i.e. desiccation, exposure to UV rays, predation, etc.) and sanitization procedures (cleaning, rinsing, chlorination), increasing their survival on food products and in manufacturing plants. Forty-five isolates collected from food and fecal samples were genotyped by pulsed field gel electrophoresis analysis with XbaI restriction enzyme and investigated by searching for toxins (stx1, stx2) and intimin (eae) genes and serogroup (O157, O26, O145, O111, O103 and O104). Afterward, the ability to develop biofilm in microtiter assay and the production of adhesive curli fimbriae and cellulose on agar plates were tested. Our study demonstrated that biofilm formation has a great variability among STEC strains and cannot be related to a specific pulsotype nor even to serogroup or presence of virulence genes.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Genotipo , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/fisiología , Adhesinas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Celulosa/metabolismo , Electroforesis en Gel de Campo Pulsado , Proteínas de Escherichia coli/genética , Heces/microbiología , Microbiología de Alimentos , Humanos , Tipificación Molecular , Serogrupo , Toxina Shiga I/genética , Toxina Shiga II/genética , Escherichia coli Shiga-Toxigénica/clasificación , Escherichia coli Shiga-Toxigénica/aislamiento & purificación
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