| 1. |
- Aspán, Anna, et al.
(författare)
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Longitudinal observational study over 38 months of verotoxigenic Escherichia coli O157: H7 status in 126 cattle herds
- 2015
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 121, s. 343-352
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Tidskriftsartikel (refereegranskat)abstract
- Verotoxigenic Escherichia coli O157:H7 (VTEC O157:H7) is an important zoonotic pathogen capable of causing infections in humans, sometimes with severe symptoms such as hemorrhagic colitis and hemolytic uremic syndrome (HUS). It has been reported that a subgroup of VTEC O157:H7, referred to as clade 8, is overrepresented among HUS cases. Cattle are considered to be the main reservoir of VTEC O157:H7 and infected animals shed the bacteria in feces without showing clinical signs of disease. The aims of the present study were: (1) to better understand how the presence of VTEC O157:H7 in the farm environment changes over an extended period of time, (2) to investigate potential risk factors for the presence of the bacteria, and (3) describe the distribution of MLVA types and specifically the occurrence of the hypervirulent strains (clade 8 strains) of VTEC O157:H7. The farm environment of 126 cattle herds in Sweden were sampled from October 2009 to December 2012 (38 months) using pooled pat and overshoe sampling. Each herd was sampled, on average, on 17 occasions (range = 1-20; median = 19), at intervals of 64 days (range = 7-205; median = 58). Verotoxigenic E. coli O157:H7 were detected on one or more occasions in 53% of the herds (n= 67). In these herds, the percentage of positive sampling occasions ranged from 6% to 72% (mean = 19%; median = 17%). Multi-locus variable number tandem repeat analysis (MLVA) typing was performed on isolates from infected herds to identify hypervirulent strains (clade 8). Clustering of MLVA profiles yielded 35 clusters and hypervirulent strains were found in 18 herds; the same cluster was often identified on consecutive samplings and in nearby farms. Using generalized estimating equations, an association was found between the probability of detecting VTEC O157:H7 and status at the preceding sampling, season, herd size, infected neighboring farms and recent introduction of animals. This study showed that the bacteria VTEC O157:H7 were spontaneously cleared from the farm environment in most infected herds over time, and key factors were identified to prevent the spread of VTEC O157:H7 between cattle herds.
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| 2. |
- Malmsten, Jonas, et al.
(författare)
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Temporal and spatial variation in Anaplasma phagocytophilum infection in Swedish moose (Alces alces)
- 2014
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Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 142, s. 1205-1213
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of Anaplasma phagocytophilum was investigated in spleen and serum samples from Swedish moose (Alces alces) in southern Sweden (island and mainland). Samples were analysed for presence of A. phagocytophilum DNA by real-time PCR (n=263), and for Anaplasma antibodies with ELISA serology (n=234). All serum samples had antibodies against A. phagocytophilum. The mean DNA-based prevalence was 26 center dot 3%, and significant (P<0 center dot 01) temporal, and spatial variation was found. Island moose had significantly (P<0 center dot 001) higher prevalence of A. phagocytophilum DNA than moose from the mainland areas. Two samples were sequenced to determine genetic variation in the 16S rRNA and groESL genes. Genetic sequence similarity with the human granulocytic anaplasmosis agent, equine granulocytic ehrlichiosis agent, and different wildlife-associated A. phagocytophilum variants were observed in the 16S rRNA and groESL genes. Our study shows that moose are exposed to A. phagocytophilum in Sweden, and represent a potential wildlife reservoir of the pathogen.
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| 3. |
- Lindahl, Susanne, et al.
(författare)
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Comparison of Sampling Sites and Laboratory Diagnostic Tests for S. equi subsp. equi in Horses from Confirmed Strangles Outbreaks
- 2013
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Ingår i: Journal of Veterinary Internal Medicine. - : Wiley. - 0891-6640 .- 1939-1676. ; 27, s. 542-547
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Tidskriftsartikel (refereegranskat)abstract
- Background Strangles is a contagious equine-specific disease caused by Streptococcus equi subsp. equi. Unfortunately, detection of S. equi can fail in up to 40% of horses with strangles. Whereas recent molecular biologic methods and sampling techniques have improved recovery of S. equi optimal sampling methods and laboratory analyses remain ill-defined. Objectives To determine the yield of S. equi from horses with acute strangles in confirmed outbreaks by field-sampling methods subjected to culture and biochemical identification, and real-time PCR directly and after culture. Animals Fifty-seven horses of varying breeds and ages from 8 strangles outbreaks. Methods Prospective study. Culture with biochemical identification and real-time PCR directly, and from culture, were performed on nasal swabs, nasopharyngeal swabs, and nasopharyngeal lavages. Results Real-time PCR directly from samples identified the highest number of infected horses, with 45/57 nasal swabs, 41/57 nasopharyngeal swabs, and 48/57 nasopharyngeal lavages S. equi positive. Biochemical identification (highest positives 22/57) was inferior to real-time PCR for S. equi recovery regardless of sampling method. Real-time PCR of nasopharyngeal lavage directly and after culture yielded 52/57 positives whereas direct real-time PCR of nasopharyngeal lavage combined with either nasopharyngeal swabs or nasal swabs yielded 53/57 positives. Three horses were negative on all samples. Conclusions and Clinical Importance Nasopharyngeal lavage analyzed by a combination of real-time PCR directly and after culture or, alternatively, real-time PCR directly on a nasopharyngeal lavage and a nasal/nasopharyngeal swab can identify S. equi in over 90% of acute strangles cases.
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| 4. |
- Söderlund, Robert, et al.
(författare)
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Prevalence and genomic characteristics of zoonotic gastro-intestinal pathogens and ESBL/pAmpC producing Enterobacteriaceae among Swedish corvid birds
- 2019
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Ingår i: Infection Ecology & Epidemiology. - : Taylor & Francis. - 2000-8686. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Wild birds pose a potential threat to animal and human health by spreading infectious diseases. In the present study, we studied the occurrence of bacterial zoonotic pathogens as well as enterobacteria with transferrable antimicrobial resistance genes among Swedish corvids.Materials and methods: Intestines from 66 jackdaws, crows, rooks and magpies from the vicinity of livestock farms at 14 locations in 7 counties were analysed by direct culture or PCR screening followed by culture. Isolates were investigated by whole-genome sequencing.Results and discussion: Campylobacter jejuni were detected in 82% and Yersinia in 3% of the birds. ESBL-producing E. coli were found in one sample (2%) and carried bla CTX-M-55. No Enterobacteriaceae with transferable carbapenem resistance were identified. No Salmonella or E. coli O157:H7 were found, but PCR analysis for enterohaemorrhagic E. coli virulence genes revealed 35% positive samples for intimin, 9% for verotoxin 1 and 17% for verotoxin 2. C. jejuni isolates from corvids were compared to previously published isolates from Swedish sources by multi-locus sequence typing based on genome sequences. All corvid C. jejuni isolates formed a cluster, intermingled with human and chicken isolates. Our results indicate that C. jejuni is ubiquitous among Swedish corvid birds, with sporadic transmission to poultry and humans.
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| 5. |
- Lindahl, Susanne, et al.
(författare)
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Tracing outbreaks of Streptococcus equi infection (strangles) in horses using sequence variation in the seM gene and pulsed-field gel electrophoresis
- 2011
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Ingår i: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 153, s. 144-149
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Tidskriftsartikel (refereegranskat)abstract
- Strangles is a serious respiratory disease in horses caused by Streptococcus equi subspecies equi (S. equi). Transmission of the disease occurs by direct contact with an infected horse or contaminated equipment. Genetically, S. equi strains are highly homogenous and differentiation of strains has proven difficult. However, the S. equi M-protein SeM contains a variable N-terminal region and has been proposed as a target gene to distinguish between different strains of S. equi and determine the source of an outbreak. In this study, strains of S. equi (n = 60) from 32 strangles outbreaks in Sweden during 1998-2003 and 2008-2009 were genetically characterized by sequencing the SeM protein gene (seM), and by pulsed-field gel electrophoresis (PFGE). Swedish strains belonged to 10 different seM types, of which five have not previously been described. Most were identical or highly similar to allele types from strangles outbreaks in the UK. Outbreaks in 2008/2009 sharing the same seM type were associated by geographic location and/or type of usage of the horses (racing stables). Sequencing of the seM gene generally agreed with pulsed-field gel electrophoresis profiles. Our data suggest that seM sequencing as a epidemiological tool is supported by the agreement between seM and PFGE and that sequencing of the SeM protein gene is more sensitive than PFGE in discriminating strains of S. equi. (C) 2011 Elsevier B.V. All rights reserved.
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| 6. |
- Loftsdottir, Heidur, et al.
(författare)
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Dynamics of insertion sequence element IS629 inactivation of verotoxin 2 genes in Escherichia coli O157:H7
- 2017
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press. - 0378-1097 .- 1574-6968. ; 364:8
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Tidskriftsartikel (refereegranskat)abstract
- There are several anecdotal reports of insertion sequence (IS) element inactivation of verotoxin genes among enterohaemorrhagic Escherichia coli of the serotype O157:H7, a pathogen causing severe gastrointestinal disease in infected humans. These insertions can be expected to drastically reduce the virulence of the bacteria. IS element inactivation has been shown to be reversible in model systems, suggesting the possibility of spontaneous restoration of virulence. In this study, traditional and high-throughput sequencing was used to characterise three patterns of IS629 inactivation of verotoxin 2 genes in EHEC O157:H7, caused by insertion or insertion followed by partial deletion. At least one of the patterns of inactivation appears to have persisted several years among cattle O157:H7, indicating it has no major effect on fitness in the animal reservoir. Digital PCR was used to directly quantify the reversal rates of the insertional inactivation of a selected isolate under laboratory conditions. Inserts were found to be absent from in the order of 1/10(5) of individual genomes, with significantly higher loss frequencies observed in cultures under nutrient-poor conditions. We conclude that strains with this type of inactivation found in food or animal samples should be considered a threat to human health, and may pose a challenge for PCR-based detection methods.
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| 7. |
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| 8. |
- Larsson, Jenny, et al.
(författare)
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Pathological and bacteriological characterization of neonatal porcine diarrhoea of uncertain aetiology
- 2015
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Ingår i: Journal of Medical Microbiology. - : Microbiology Society. - 0022-2615 .- 1473-5644. ; 64, s. 916-926
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Tidskriftsartikel (refereegranskat)abstract
- Neonatal porcine diarrhoea of uncertain aetiology has been reported from a number of countries. This study investigated 50 diarrhoeic and 19 healthy piglets from 10 affected Swedish herds. The piglets were blood-sampled for analysis of serum gamma-globulin and necropsied, and the intestines were sampled for histopathology and cultured for Escherichia coli, Clostridium perfringens and Clostridium difficile. Escherichia coli isolates (n=276) were examined by PCR for virulence genes encoding LT, STa, STb, EAST1, VT2e, F4, F5, F6, F18, F41, AIDA-I, intimin, and for the genes aaiC and aggR. Selected isolates were analysed for additional virulence genes by a microarray and subjected to O-typing. Clostridium perfringens isolates (n=152) were examined by PCR for genes encoding major toxins, enterotoxin and beta2-toxin. There was no difference in serum gamma-globulin concentration between diarrhoeic and non-diarrhoeic piglets, and pathological lesions in the intestines were generally mild. Porcine enterotoxigenic Escherichia coli, a common cause of piglet diarrhoea, was only found in two piglets. Further, the virulence gene profiling did not suggest involvement of other diarrhoeogenic pathotypes of Escherichia coli. Growth of Clostridium perfringens did not differ between diarrhoeic and non-diarrhoeic piglets. All isolates were type A, all were negative for enterotoxin, and 151 of 152 isolates were beta2-toxin positive. In pigs >= 2 days old, moderate to profuse growth of Clostridium difficile was more common in the controls. In conclusion, it was not possible to relate Escherichia coli, Clostridium perfringens type A and C or Clostridium difficile to neonatal porcine diarrhoea in any of the investigated herds.
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| 10. |
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