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Steketee PC, Paxton E, Barrett MP, Pearce MC, Connelley TK, Morrison LJ. Anti-parasitic benzoxaboroles are ineffective against Theileria parva in vitro. Int J Parasitol Drugs Drug Resist 2023; 23:71-77. [PMID: 37866107 PMCID: PMC10623109 DOI: 10.1016/j.ijpddr.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/24/2023]
Abstract
East Coast Fever (ECF) is a disease affecting cattle in sub-Saharan Africa, caused by the tick-borne Apicomplexan pathogen Theileria parva. The disease is a major problem for cattle farmers in affected regions and there are few methods of control, including a complex infection and treatment vaccine, expensive chemotherapy, and the more widespread tick control through acaricides. New intervention strategies are, therefore, sorely needed. Benzoxaboroles are a versatile class of boron-heterocyclic compounds with demonstrable pharmacological activity against a diverse group of pathogens, including those related to T. parva. In this study, the in vitro efficacy of three benzoxaboroles against the intracellular schizont stage of T. parva was investigated using a flow cytometry approach. Of the benzoxaboroles tested, only one showed any potency, albeit only at high concentrations, even though there is high protein sequence similarity in the CPSF3 protein target compared to other protozoan pathogen species. This finding suggests that benzoxaboroles currently of interest for the treatment of African animal trypanosomiasis, toxoplasmosis, cryptosporidiosis and malaria may not be suitable for the treatment of ECF. We conclude that testing of further benzoxaborole compounds is needed to fully determine whether any lead compounds can be identified to target T. parva.
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Affiliation(s)
- Pieter C Steketee
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Edith Paxton
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Michael P Barrett
- Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Michael C Pearce
- Global Alliance for Livestock Medicines, Doherty Building, Pentlands Science Park, Edinburgh, EH26 0PZ, UK
| | - Timothy K Connelley
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Liam J Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK.
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2
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Hoyle DV, Wee BA, Macleod K, Chase-Topping ME, Bease AG, Tongue SC, Gally DL, Delannoy S, Fach P, Pearce MC, Gunn GJ, Holmes A, Allison L. Phylogenetic relationship and virulence composition of Escherichia coli O26:H11 cattle and human strain collections in Scotland; 2002-2020. Front Microbiol 2023; 14:1260422. [PMID: 38029122 PMCID: PMC10657854 DOI: 10.3389/fmicb.2023.1260422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/05/2023] [Indexed: 12/01/2023] Open
Abstract
O26 is the commonest non-O157 Shiga toxin (stx)-producing Escherichia coli serogroup reported in human infections worldwide. Ruminants, particularly cattle, are the primary reservoir source for human infection. In this study, we compared the whole genomes and virulence profiles of O26:H11 strains (n = 99) isolated from Scottish cattle with strains from human infections (n = 96) held by the Scottish Escherichia coli O157/STEC Reference Laboratory, isolated between 2002 and 2020. Bovine strains were from two national cross-sectional cattle surveys conducted between 2002-2004 and 2014-2015. A maximum likelihood phylogeny was constructed from a core-genome alignment with the O26:H11 strain 11368 reference genome. Genomes were screened against a panel of 2,710 virulence genes using the Virulence Finder Database. All stx-positive bovine O26:H11 strains belonged to the ST21 lineage and were grouped into three main clades. Bovine and human source strains were interspersed, and the stx subtype was relatively clade-specific. Highly pathogenic stx2a-only ST21 strains were identified in two herds sampled in the second cattle survey and in human clinical infections from 2010 onwards. The closest pairwise distance was 9 single-nucleotide polymorphisms (SNPs) between Scottish bovine and human strains and 69 SNPs between the two cattle surveys. Bovine O26:H11 was compared to public EnteroBase ST29 complex genomes and found to have the greatest commonality with O26:H11 strains from the rest of the UK, followed by France, Italy, and Belgium. Virulence profiles of stx-positive bovine and human strains were similar but more conserved for the stx2a subtype. O26:H11 stx-negative ST29 (n = 17) and ST396 strains (n = 5) were isolated from 19 cattle herds; all were eae-positive, and 10 of these herds yielded strains positive for ehxA, espK, and Z2098, gene markers suggestive of enterohaemorrhagic potential. There was a significant association (p < 0.001) between nucleotide sequence percent identity and stx status for the bacteriophage insertion site genes yecE for stx2 and yehV for stx1. Acquired antimicrobial resistance genes were identified in silico in 12.1% of bovine and 17.7% of human O26:H11 strains, with sul2, tet, aph(3″), and aph(6″) being most common. This study describes the diversity among Scottish bovine O26:H11 strains and investigates their relationship to human STEC infections.
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Affiliation(s)
- Deborah V. Hoyle
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Bryan A. Wee
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Kareen Macleod
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Margo E. Chase-Topping
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Andrew G. Bease
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Sue C. Tongue
- Centre for Epidemiology and Planetary Health, Department of Veterinary and Animal Science, North Faculty, Scotland’s Rural College (SRUC), Inverness, United Kingdom
| | - David L. Gally
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Edinburgh, United Kingdom
| | - Sabine Delannoy
- Unité ColiPath – Plateforme IdentyPath, Laboratoire de Sécurité des Aliments, Agence Nationale De Sécurité Sanitaire de l’alimentation, de l’environnement et du travail (ANSES), Maisons-Alfort, France
| | - Patrick Fach
- Unité ColiPath – Plateforme IdentyPath, Laboratoire de Sécurité des Aliments, Agence Nationale De Sécurité Sanitaire de l’alimentation, de l’environnement et du travail (ANSES), Maisons-Alfort, France
| | - Michael C. Pearce
- Centre for Epidemiology and Planetary Health, Department of Veterinary and Animal Science, North Faculty, Scotland’s Rural College (SRUC), Inverness, United Kingdom
| | - George J. Gunn
- Centre for Epidemiology and Planetary Health, Department of Veterinary and Animal Science, North Faculty, Scotland’s Rural College (SRUC), Inverness, United Kingdom
| | - Anne Holmes
- Scottish E. coli O157/STEC Reference Laboratory (SERL), Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Lesley Allison
- Scottish E. coli O157/STEC Reference Laboratory (SERL), Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
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3
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Contreras Garcia M, Walshe E, Steketee PC, Paxton E, Lopez-Vidal J, Pearce MC, Matthews KR, Ezzahra-Akki F, Evans A, Fairlie-Clark K, Matthews JB, Grey F, Morrison LJ. Comparative Sensitivity and Specificity of the 7SL sRNA Diagnostic Test for Animal Trypanosomiasis. Front Vet Sci 2022; 9:868912. [PMID: 35450136 PMCID: PMC9017285 DOI: 10.3389/fvets.2022.868912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
Animal trypanosomiasis (AT) is a significant livestock disease, affecting millions of animals across Sub-Saharan Africa, Central and South America, and Asia, and is caused by the protozoan parasites Trypanosoma brucei, Trypanosoma vivax, and Trypanosoma congolense, with the largest economic impact in cattle. There is over-reliance on presumptive chemotherapy due to inadequate existing diagnostic tests, highlighting the need for improved AT diagnostics. A small RNA species, the 7SL sRNA, is excreted/secreted by trypanosomes in infected animals, and has been previously shown to reliably diagnose active infection. We sought to explore key properties of 7SL sRNA RT-qPCR assays; namely, assessing the potential for cross-reaction with the widespread and benign Trypanosoma theileri, directly comparing assay performance against currently available diagnostic methods, quantitatively assessing specificity and sensitivity, and assessing the rate of decay of 7SL sRNA post-treatment. Results showed that the 7SL sRNA RT-qPCR assays specific for T. brucei, T. vivax, and T. congolense performed better than microscopy and DNA PCR in detecting infection. The 7SL sRNA signal was undetectable or significantly reduced by 96-h post treatment; at 1 × curative dose there was no detectable signal in 5/5 cattle infected with T. congolense, and in 3/5 cattle infected with T. vivax, with the signal being reduced 14,630-fold in the remaining two T. vivax cattle. Additionally, the assays did not cross-react with T. theileri. Finally, by using a large panel of validated infected and uninfected samples, the species-specific assays are shown to be highly sensitive and specific by receiver operating characteristic (ROC) analysis, with 100% sensitivity (95% CI, 96.44-100%) and 100% specificity (95% CI, 96.53-100%), 96.73% (95% CI, 95.54-99.96%) and 99.19% specificity (95% CI, 92.58-99.60%), and 93.42% (95% CI, 85.51-97.16% %) and 82.43% specificity (95% CI, 72.23-89.44% %) for the T brucei, T. congolense and T. vivax assays, respectively, under the conditions used. These findings indicate that the 7SL sRNA has many attributes that would be required for a potential diagnostic marker of AT: no cross-reaction with T. theileri, high specificity and sensitivity, early infection detection, continued signal even in the absence of detectable parasitaemia in blood, and clear discrimination between infected and treated animals.
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Affiliation(s)
- Maria Contreras Garcia
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Emily Walshe
- Roslin Technologies Limited, Roslin Innovation Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Pieter C Steketee
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Edith Paxton
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Javier Lopez-Vidal
- Ashworth Laboratories, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael C Pearce
- Global Alliance for Livestock Veterinary Medicines, Edinburgh, United Kingdom
| | - Keith R Matthews
- Ashworth Laboratories, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Karen Fairlie-Clark
- Roslin Technologies Limited, Roslin Innovation Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Jacqueline B Matthews
- Roslin Technologies Limited, Roslin Innovation Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Finn Grey
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
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4
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Bisschop SPR, Peters A, Domingue G, Pearce MC, Verwey J, Poolman P. Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage in vivo. Gates Open Res 2022; 5:76. [PMID: 34859194 PMCID: PMC8595976 DOI: 10.12688/gatesopenres.13212.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2021] [Indexed: 11/20/2022] Open
Abstract
Background This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five
in vivo passages through SPF chickens. Methods Study design was to international requirements including European Pharmacopoeia, Ph. Eur., v9.0 04/2013:0450, 2013. I-2 Working Seed (WS) was compared with five-times-passaged I-2 WS (5XP WS) in intracerebral pathogenicity index (ICPI), F
o cleavage site sequencing and Safety tests. Results The first passage series used a 50% brain: 50% tracheal tissue challenge homogenate and was unsuccessful as I-2 was not detected after the fourth passage.
A second passage series used 10% brain: 90% tracheal tissue homogenates. I-2 was isolated from tracheal tissue in each passage. However harvested titres were below the minimum challenge level (10
7 EID
50) specified for the ICPI and Safety tests, possibly reflecting I-2’s inherently low pathogenicity (interestingly caecal tonsils yielded significant titres). Given this the WS and 5XP WS comparisons proceeded. ICPI values were 0.104 and 0.073 for the WS group and the 5XP WS group respectively confirming that I-2, whether passaged or not, expressed low pathogenicity. F
0 amino-acid sequences for both WS and 5XP WS were identified as
112R-K-Q-G-R-↓-L-I-G
119 and so compatible with those of avirulent ND viruses. In safety, no abnormal clinical signs were observed in both groups except for two chicks in the 5XP WS group, where one bird was withdrawn due to a vent prolapse, and another bird died with inconclusive necropsy results. Conclusions: These data, the issue of low passage titres with little or no virus isolation from brain tissues and the genomic copy approach suggest a need to amend Ph. Eur. v9.0 04/2013:0450, 2013 for naturally attenuated, low pathogenicity vaccine viruses such as I-2. From an international regulatory perspective, the study provides further definitive data demonstrating that Newcastle disease vaccine virus I-2 is safe for use.
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Affiliation(s)
- Shahn P R Bisschop
- Avimune (Pty.) Ltd, Queenswood, Pretoria, South Africa.,Poultry Reference Centre, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Andrew Peters
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,Supporting Evidence based Interventions-Livestock, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, UK
| | - Gil Domingue
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,GD Associates, Fairmilehead, Edinburgh, Scotland, UK
| | - Michael C Pearce
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,Epidemiological Research Unit, Scotland's Rural College, An Lòchran, Inverness, UK
| | | | - Petrus Poolman
- Poultry Reference Centre, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Kuipers Group (Pty.) Ltd, Zeekoeigat, Pretoria, South Africa
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5
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Bisschop SPR, Peters A, Domingue G, Pearce MC, Verwey J, Poolman P. Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage in vivo. Gates Open Res 2021; 5:76. [PMID: 34859194 DOI: 10.12688/gatesopenres.13212.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2021] [Indexed: 11/20/2022] Open
Abstract
Background This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five in vivo passages through SPF chickens. Methods Study design was to international requirements including European Pharmacopoeia, Ph. Eur., v9.0 04/2013:0450, 2013. I-2 Working Seed (WS) was compared with five-times-passaged I-2 WS (5XP WS) in intracerebral pathogenicity index (ICPI), F o cleavage site sequencing and Safety tests. Results The first passage series used a 50% brain: 50% tracheal tissue challenge homogenate and was unsuccessful as I-2 was not detected after the fourth passage. A second passage series used 10% brain: 90% tracheal tissue homogenates. I-2 was isolated from tracheal tissue in each passage. However harvested titres were below the minimum challenge level (10 7 EID 50) specified for the ICPI and Safety tests, possibly reflecting I-2's inherently low pathogenicity (interestingly caecal tonsils yielded significant titres). Given this the WS and 5XP WS comparisons proceeded. ICPI values were 0.104 and 0.073 for the WS group and the 5XP WS group respectively confirming that I-2, whether passaged or not, expressed low pathogenicity. F 0 amino-acid sequences for both WS and 5XP WS were identified as 112R-K-Q-G-R-↓-L-I-G 119 and so compatible with those of avirulent ND viruses. In safety, no abnormal clinical signs were observed in both groups except for two chicks in the 5XP WS group, where one bird was withdrawn due to a vent prolapse, and another bird died with inconclusive necropsy results. Conclusions: These data, the issue of low passage titres with little or no virus isolation from brain tissues and the genomic copy approach suggest a need to amend Ph. Eur. v9.0 04/2013:0450, 2013 for naturally attenuated, low pathogenicity vaccine viruses such as I-2. From an international regulatory perspective, the study provides further definitive data demonstrating that Newcastle disease vaccine virus I-2 is safe for use.
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Affiliation(s)
- Shahn P R Bisschop
- Avimune (Pty.) Ltd, Queenswood, Pretoria, South Africa.,Poultry Reference Centre, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Andrew Peters
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,Supporting Evidence based Interventions-Livestock, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, UK
| | - Gil Domingue
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,GD Associates, Fairmilehead, Edinburgh, Scotland, UK
| | - Michael C Pearce
- GALVmed, Pentlands Science Park, Midlothian, Scotland, UK.,Epidemiological Research Unit, Scotland's Rural College, An Lòchran, Inverness, UK
| | | | - Petrus Poolman
- Poultry Reference Centre, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Kuipers Group (Pty.) Ltd, Zeekoeigat, Pretoria, South Africa
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6
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Bisschop SP, Peters A, Domingue G, Pearce MC, Verwey J, Poolman P. Newcastle disease vaccine virus I-2 fails to acquire virulence during repeated passage in vivo. Gates Open Res 2021; 5:76. [DOI: 10.12688/gatesopenres.13212.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2021] [Indexed: 11/20/2022] Open
Abstract
Background This study determined whether the naturally attenuated, thermotolerant Newcastle disease vaccine virus I-2 could acquire virulence after five in vivo passages through SPF chickens. Methods Study design was to international requirements including European Pharmacopoeia, Ph. Eur., v9.0 04/2013:0450, 2013. I-2 Working Seed (WS) was compared with five-times-passaged I-2 WS (5XP WS) in intracerebral pathogenicity index (ICPI), Fo cleavage site sequencing and Safety tests. Results The first passage series used a 50% brain: 50% tracheal tissue challenge homogenate and was unsuccessful as I-2 was not detected after the fourth passage. A second passage series used 10% brain: 90% tracheal tissue homogenates. I-2 was isolated from tracheal tissue in each passage. However harvested titres were below the minimum challenge level (107 EID50) specified for the ICPI and Safety tests, possibly reflecting I-2’s inherently low pathogenicity (interestingly caecal tonsils yielded significant titres). Given this the WS and 5XP WS comparisons proceeded. ICPI values were 0.104 and 0.073 for the WS group and the 5XP WS group respectively confirming that I-2, whether passaged or not, expressed low pathogenicity. F0 amino-acid sequences for both WS and 5XP WS were identified as 112R-K-Q-G-R-↓-L-I-G119 and so compatible with those of avirulent ND viruses. In safety, no abnormal clinical signs were observed in both groups except for two chicks in the 5XP WS group, where one bird was withdrawn due to a vent prolapse, and another bird died with inconclusive necropsy results. Conclusions: These data, the issue of low passage titres with little or no virus isolation from brain tissues and the genomic copy approach suggest a need to amend Ph. Eur. v9.0 04/2013:0450, 2013 for naturally attenuated, low pathogenicity vaccine viruses such as I-2. These results add to the literature and field data demonstrating that Newcastle Disease vaccine virus I-2 is safe for use.
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7
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Rypuła K, Płoneczka-Janeczko K, Bierowiec K, Chorbiński P, Pearce MC, Lesiak M. Prevalence of antibodies to Leptospira hardjo in bulk tank milk from unvaccinated dairy herds in the south-west region of Poland. Berl Munch Tierarztl Wochenschr 2014; 127:247-250. [PMID: 24881277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Bulk tank milk samples were collected from 309 randomly selected dairy cattle herds from the south-western region of Poland in 2010-2011. Samples were tested for antibodies against Leptospira hardjo using DAS-ELISA. Herd level seroprevalence of antibodies against this serovar was low (3.2%). Sample value related to positive control value (S/P ratio) results were highest in herds with 51-100 and 101-500 animals, being 4.6 and 4.1% respectively. The S/P ratio of positive samples indicated a low percentage of infected animals in positive herds.
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Herbert LJ, Vali L, Hoyle DV, Innocent G, McKendrick IJ, Pearce MC, Mellor D, Porphyre T, Locking M, Allison L, Hanson M, Matthews L, Gunn GJ, Woolhouse ME, Chase-Topping ME. E. coli O157 on Scottish cattle farms: evidence of local spread and persistence using repeat cross-sectional data. BMC Vet Res 2014; 10:95. [PMID: 24766709 PMCID: PMC4022360 DOI: 10.1186/1746-6148-10-95] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 03/26/2014] [Indexed: 11/30/2022] Open
Abstract
Background Escherichia coli (E. coli) O157 is a virulent zoonotic strain of enterohaemorrhagic E. coli. In Scotland (1998-2008) the annual reported rate of human infection is 4.4 per 100,000 population which is consistently higher than other regions of the UK and abroad. Cattle are the primary reservoir. Thus understanding infection dynamics in cattle is paramount to reducing human infections. A large database was created for farms sampled in two cross-sectional surveys carried out in Scotland (1998 - 2004). A statistical model was generated to identify risk factors for the presence of E. coli O157 on farms. Specific hypotheses were tested regarding the presence of E. coli O157 on local farms and the farms previous status. Pulsed-field gel electrophoresis (PFGE) profiles were further examined to ascertain whether local spread or persistence of strains could be inferred. Results The presence of an E. coli O157 positive local farm (average distance: 5.96km) in the Highlands, North East and South West, farm size and the number of cattle moved onto the farm 8 weeks prior to sampling were significant risk factors for the presence of E. coli O157 on farms. Previous status of a farm was not a significant predictor of current status (p = 0.398). Farms within the same sampling cluster were significantly more likely to be the same PFGE type (p < 0.001), implicating spread of strains between local farms. Isolates with identical PFGE types were observed to persist across the two surveys, including 3 that were identified on the same farm, suggesting an environmental reservoir. PFGE types that were persistent were more likely to have been observed in human clinical infections in Scotland (p < 0.001) from the same time frame. Conclusions The results of this study demonstrate the spread of E. coli O157 between local farms and highlight the potential link between persistent cattle strains and human clinical infections in Scotland. This novel insight into the epidemiology of Scottish E. coli O157 paves the way for future research into the mechanisms of transmission which should help with the design of control measures to reduce E. coli O157 from livestock-related sources.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Margo E Chase-Topping
- Centre for Immunity, Infection and Evolution, University of Edinburgh, King's Buildings, Edinburgh, UK.
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9
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Pearce MC, Venter M, Schouwstra T, Van Eeden C, Jansen van Vuren P, Paweska J, Liu B, Du Plessis A. Serum neutralising antibody response of seronegative horses against lineage 1 and lineage 2 West Nile virus following vaccination with an inactivated lineage 1 West Nile virus vaccine. J S Afr Vet Assoc 2013. [DOI: 10.4102/jsava.v84i1.1052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Lineage 2 West Nile virus (WNV) strains are endemic in South Africa and cause severe neurological disease in horses. An inactivated lineage 1 vaccine, Duvaxyn WNV, protects mice against challenge with a neuroinvasive South African lineage 2 strain of WNV. To evaluate the potential of Duvaxyn WNV to protect horses against lineage 2 strains of WNV, serum neutralising antibody responses of horses against lineage 1 WNV strain NY385/99 and lineage 2 WNV strain SPU93/01, isolated from a human with meningo-encephalitis in South Africa, were compared following vaccination with two doses of Duvaxyn WNV, 28 days apart, and a third dose one year later. Twenty-two seronegative horses were randomly assigned to two treatment groups: 16 to a vaccinated group and six retained as unvaccinated controls. Blood samples were taken from all horses on study days 0, 28, 35, 42, 49, 91, 141, 182, 231, 274, 322, 364 and 413. Primovaccination with Duvaxyn WNV resulted in high titres of serum neutralising antibodies against both strains. Following a single dose of Duvaxyn WNV on day 399, one year after primovaccination, there was a strong anamnestic response with a log25-fold rise in the titres of neutralising antibodies against strains NY385/99 and SPU93/01. These results provide further evidence that Duvaxyn WNV is likely to protect horses against infection with lineage 2 strains of WNV and that a single annual booster may be sufficient to maintain immunity against lineage 2 WNV infection in horses.
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10
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Mackay J, Pearce MC, Thevasagayam S, Doran O. Fatty acid composition and lipogenic enzyme protein expression in subcutaneous adipose tissue of male pigs vaccinated against boar taint, barrows, and entire boars. J Anim Sci 2012; 91:395-404. [PMID: 23048133 DOI: 10.2527/jas.2011-4685] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Objectives of this study were to compare fatty acid composition of subcutaneous adipose tissue of entire boars, barrows, and male pigs vaccinated against boar taint with a vaccine containing a GnRH analogue-protein conjugate (Improvac, Pfizer Animal Health) and to investigate the association between fatty acid composition and protein expression of key lipogenic enzymes in entire boars, barrows, and vaccinated pigs. Differences between groups were observed in the content of total SFA (P≤0.001), MUFA (P=0.035), and n-6 PUFA (P≤0.001) but not n-3 PUFA (P=0.373). Total SFA were greater (P<0.001) in barrows and vaccinated pigs compared with entire animals. This was accompanied by an increase (P<0.05) in the protein expression of the lipogenic enzyme fatty acid synthase in barrows and vaccinated pigs. Total MUFA content was increased (P<0.001) in barrows compared with entire and vaccinated pigs. This was not accompanied (P>0.05) by an increase in expression of stearoyl-CoA desaturase protein, the enzyme catalyzing MUFA biosyntheses. Total n-6 PUFA content did not differ (P<0.001) between entire and vaccinated pigs but was lower in barrows. Expression of Δ6-desaturase protein, one of the key enzymes of PUFA biosynthesis, was greater (P<0.05) in vaccinated pigs than in barrows but did not differ significantly between vaccinated and entire animals. We conclude that fatty acid profile of animals vaccinated against boar taint is similar to that of entire male pigs and that the effect of physical castration and vaccination on fatty acid composition involves changes in lipogenic enzyme protein expression.
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Affiliation(s)
- J Mackay
- Centre for Research in Biosciences, Faculty of Health and Life Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK
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11
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Traversa D, Castagna G, von Samson-Himmelstjerna G, Meloni S, Bartolini R, Geurden T, Pearce MC, Woringer E, Besognet B, Milillo P, D’Espois M. Efficacy of major anthelmintics against horse cyathostomins in France. Vet Parasitol 2012; 188:294-300. [DOI: 10.1016/j.vetpar.2012.03.048] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/21/2012] [Accepted: 03/24/2012] [Indexed: 10/28/2022]
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Chase-Topping ME, Rosser T, Allison LJ, Courcier E, Evans J, McKendrick IJ, Pearce MC, Handel I, Caprioli A, Karch H, Hanson MF, Pollock KGJ, Locking ME, Woolhouse MEJ, Matthews L, Low JC, Gally DL. Pathogenic potential to humans of bovine Escherichia coli O26, Scotland. Emerg Infect Dis 2012; 18:439-48. [PMID: 22377426 PMCID: PMC3309639 DOI: 10.3201/eid1803.111236] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli O26 and O157 have similar overall prevalences in cattle in Scotland, but in humans, Shiga toxin-producing E. coli O26 infections are fewer and clinically less severe than E. coli O157 infections. To investigate this discrepancy, we genotyped E. coli O26 isolates from cattle and humans in Scotland and continental Europe. The genetic background of some strains from Scotland was closely related to that of strains causing severe infections in Europe. Nonmetric multidimensional scaling found an association between hemolytic uremic syndrome (HUS) and multilocus sequence type 21 strains and confirmed the role of stx(2) in severe human disease. Although the prevalences of E. coli O26 and O157 on cattle farms in Scotland are equivalent, prevalence of more virulent strains is low, reducing human infection risk. However, new data on E. coli O26-associated HUS in humans highlight the need for surveillance of non-O157 enterohemorrhagic E. coli and for understanding stx(2) phage acquisition.
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Affiliation(s)
- Margo E Chase-Topping
- Centre for Immunity, Infection, and Evolution, University of Edinburgh, Kings Buildings, Edinburgh EH9 3J5, UK.
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13
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Schmidt T, Calabrese JM, Grodzycki M, Paulick M, Pearce MC, Rau F, von Borell E. Impact of single-sex and mixed-sex group housing of boars vaccinated against GnRF or physically castrated on body lesions, feeding behaviour and weight gain. Appl Anim Behav Sci 2011. [DOI: 10.1016/j.applanim.2010.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Pearce MC, Chase-Topping ME, McKendrick IJ, Mellor DJ, Locking ME, Allison L, Ternent HE, Matthews L, Knight HI, Smith AW, Synge BA, Reilly W, Low JC, Reid SWJ, Gunn GJ, Woolhouse MEJ. Temporal and spatial patterns of bovine Escherichia coli O157 prevalence and comparison of temporal changes in the patterns of phage types associated with bovine shedding and human E. coli O157 cases in Scotland between 1998-2000 and 2002-2004. BMC Microbiol 2009; 9:276. [PMID: 20040112 PMCID: PMC2808314 DOI: 10.1186/1471-2180-9-276] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 12/29/2009] [Indexed: 11/10/2022] Open
Abstract
Background Escherichia coli O157 is an important cause of acute diarrhoea, haemorrhagic colitis and, especially in children, haemolytic uraemic syndrome (HUS). Incidence rates for human E. coli O157 infection in Scotland are higher than most other United Kingdom, European and North American countries. Cattle are considered the main reservoir for E. coli O157. Significant associations between livestock related exposures and human infection have been identified in a number of studies. Results Animal Studies: There were no statistically significant differences (P = 0.831) in the mean farm-level prevalence between the two studies (SEERAD: 0.218 (95%CI: 0.141-0.32); IPRAVE: 0.205 (95%CI: 0.135-0.296)). However, the mean pat-level prevalence decreased from 0.089 (95%CI: 0.075-0.105) to 0.040 (95%CI: 0.028-0.053) between the SEERAD and IPRAVE studies respectively (P < 0.001). Highly significant (P < 0.001) reductions in mean pat-level prevalence were also observed in the spring, in the North East and Central Scotland, and in the shedding of phage type (PT) 21/28. Human Cases: Contrasting the same time periods, there was a decline in the overall comparative annual reported incidence of human cases as well as in all the major PT groups except 'Other' PTs. For both cattle and humans, the predominant phage type between 1998 and 2004 was PT21/28 comprising over 50% of the positive cattle isolates and reported human cases respectively. The proportion of PT32, however, was represented by few (<5%) of reported human cases despite comprising over 10% of cattle isolates. Across the two studies there were differences in the proportion of PTs 21/28, 32 and 'Other' PTs in both cattle isolates and reported human cases; however, only differences in the cattle isolates were statistically significant (P = 0.002). Conclusion There was no significant decrease in the mean farm-level prevalence of E. coli O157 between 1998 and 2004 in Scotland, despite significant declines in mean pat-level prevalence. Although there were declines in the number of human cases between the two study periods, there is no statistically significant evidence that the overall rate (per 100,000 population) of human E. coli O157 infections in Scotland over the last 10 years has altered. Comparable patterns in the distribution of PTs 21/28 and 32 between cattle and humans support a hypothesized link between the bovine reservoir and human infections. This emphasizes the need to apply and improve methods to reduce bovine shedding of E. coli O157 in Scotland where rates appear higher in both cattle and human populations, than in other countries.
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15
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Claus R, Lacorn M, Danowski K, Pearce MC, Bauer A. Short-term endocrine and metabolic reactions before and after second immunization against GnRH in boars. Vaccine 2007; 25:4689-96. [PMID: 17485149 DOI: 10.1016/j.vaccine.2007.04.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 02/27/2007] [Accepted: 04/02/2007] [Indexed: 11/22/2022]
Abstract
Immunization of boars against GnRH inhibits synthesis of testicular steroids including androstenone (sex odour). Timing of the second vaccination (anamnestic reaction) should occur as late as possible to maintain anabolic effects of testicular hormones, but early enough to remove androstenone from body fat. Five catheterized boars received the second dose (Improvac) at age 22 weeks. Titre, hormones and parameters reflecting protein turnover were determined in blood. An increased antibody titre and drop of LH and steroids occurred within 5 days. Metabolism adapted after 7 days. Results from this study in conjunction with previous work suggest that after two doses of Improvac given 4 weeks apart, clearance of androstenone from body fat may be achieved as early as 3 weeks after the second vaccination. Thus, it might be possible to extend the duration of anabolic effect in male pig production.
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Affiliation(s)
- Rolf Claus
- Universität Hohenheim, Institut für Tierhaltung und Tierzüchtung, Garbenstrasse 17, Stuttgart, Germany.
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16
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Chase-Topping ME, McKendrick IJ, Pearce MC, MacDonald P, Matthews L, Halliday J, Allison L, Fenlon D, Low JC, Gunn G, Woolhouse MEJ. Risk factors for the presence of high-level shedders of Escherichia coli O157 on Scottish farms. J Clin Microbiol 2007; 45:1594-603. [PMID: 17360845 PMCID: PMC1865900 DOI: 10.1128/jcm.01690-06] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli O157 infections are the cause of sporadic or epidemic cases of often bloody diarrhea that can progress to hemolytic uremic syndrome (HUS), a systematic microvascular syndrome with predominantly renal and neurological complications. HUS is responsible for most deaths associated with E. coli O157 infection. From March 2002 to February 2004, approximately 13,000 fecal pat samples from 481 farms with finishing/store cattle throughout Scotland were examined for the presence of E. coli O157. A total of 441 fecal pats from 91 farms tested positive for E. coli O157. From the positive samples, a point estimate for high-level shedders was identified using mixture distribution analysis on counts of E. coli O157. Models were developed based on the confidence interval surrounding this point estimate (high-level shedder, greater than 10(3) or greater than 10(4) CFU g(-1) feces). The mean prevalence on high-level-shedding farms was higher than that on low-level-shedding farms. The presence of a high-level shedder on a farm was found to be associated with a high proportion of low-level shedding, consistent with the possibility of a higher level of transmission. Analysis of risk factors associated with the presence of a high-level shedder on a farm suggested the importance of the pathogen and individual host rather than the farm environment. The proportion of high-level shedders of phage 21/28 was higher than expected by chance. Management-related risk factors that were identified included the type of cattle (female breeding cattle) and cattle stress (movement and weaning), as opposed to environmental factors, such as water supply and feed.
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17
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Vali L, Hamouda A, Hoyle DV, Pearce MC, Whitaker LHR, Jenkins C, Knight HI, Smith AW, Amyes SGB. Antibiotic resistance and molecular epidemiology of Escherichia coli O26, O103 and O145 shed by two cohorts of Scottish beef cattle. J Antimicrob Chemother 2007; 59:403-10. [PMID: 17289773 DOI: 10.1093/jac/dkl491] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to identify the profile of antibiotic resistance among E. coli O26, O103 and O145 in two cohorts of Scottish beef cattle on two farms and to determine whether there is an association between resistant phenotypes and the genotypic PFGE patterns to suggest clonality among resistant strains. METHODS MICs of 11 antibiotics for 297 E. coli O26, 152 E. coli O103 and 13 E. coli O145 were determined. Isolates were screened for the presence integrons 1 and 2 and the virulence factors stx1, stx2, eaeA and ehxA by PCR with specific primers. PFGE subtyping was performed after digestion with XbaI endonuclease. RESULTS Among E. coli O26, O103 and O145 there were four, four and one isolates, respectively, that harboured a class 1 integron. A class 2 integron was detected in only one O145 isolate. Diversity in PFGE patterns was higher among E. coli O103 and O145 strains compared with the O26 serotype; and PFGE demonstrated 13, 27 and 6 different patterns among O26, O103 and O145 isolates, respectively. Selective PFGE types that harboured virulence factors were widespread among the cattle population throughout the sampling period. There were multiply resistant isolates that were of similar PFGE patterns. CONCLUSIONS The dissemination and persistence of certain PFGE genotypes among the cattle population was evident in this study. Certain resistance phenotypes, especially among E. coli O26 isolates, were associated with distinct PFGE clones.
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Affiliation(s)
- Leila Vali
- Molecular Chemotherapy, Centre for Infectious Diseases, The Chancellor's Building, 49 Little France Crescent, University of Edinburgh, Edinburgh EH16 4SB, UK
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18
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Liu WC, Shaw DJ, Matthews L, Hoyle DV, Pearce MC, Yates CM, Low JC, Amyes SGB, Gunn GJ, Woolhouse MEJ. Modelling the epidemiology and transmission of Verocytotoxin-producing Escherichia coli serogroups O26 and O103 in two different calf cohorts. Epidemiol Infect 2007; 135:1316-23. [PMID: 17224085 PMCID: PMC2870690 DOI: 10.1017/s0950268806007722] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Mathematical models are constructed to investigate the population dynamics of Verocytotoxin-producing Escherichia coli (VTEC) serogroups O26 and O103 in two different calf cohorts. We compare the epidemiological characteristics of these two serogroups within the same calf cohort as well as the same serogroups between the two calf cohorts. The sources of infection are quantified for both calf cohort studies. VTEC serogroups O26 and O103 mainly differ in the rate at which calves acquire infection from sources other than infected calves, while infected calves typically remain infectious for less than 1 week regardless of the serogroups. Fewer than 20% of VTEC-positive samples are the result of calf-to-calf transmission. PFGE typing data are available for VTEC-positive samples to further subdivide the serogroup data in one of the two calf cohort studies. For serogroup O26 but not O103, there is evidence for unequal environmental exposure to infection with different PFGE types.
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Affiliation(s)
- W-C Liu
- Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, Midlothian, UK.
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19
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Vali L, Hamouda A, Pearce MC, Knight HI, Evans J, Amyes SGB. Detection of genetic diversity by pulsed-field gel electrophoresis among Escherichia coli O157 isolated from bovine faecal samples by immunomagnetic separation technique. Lett Appl Microbiol 2007; 44:19-23. [PMID: 17209809 DOI: 10.1111/j.1472-765x.2006.02034.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Escherichia coli O157 is considered to be one of most important human pathogens of animal origin which causes serious clinical complications. One of the most common methods to isolate E. coli O157 is the immunomagnetic separation (IMS) technique which employs specific antibodies coupled to magnetic beads to bind and extract cells from enrichment broths followed by plating onto sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC) plates. The aim of this study was to determine strain variation by pulsed-field gel electrophoresis (PFGE) among E. coli O157 on IMS/CT-SMAC plates. METHODS AND RESULTS Every suspect colony of E. coli O157 was tested following isolation by the IMS/CT-SMAC technique. From 124 colonies detected; six XbaI-PFGE profiles were identified. CONCLUSIONS Our results demonstrate that mixed populations of E. coli O157 with distinguishable PFGE profiles that are simultaneously present in bovine faeces can be isolated with IMS/CT-SMAC technique. SIGNIFICANCE AND IMPACT OF THE STUDY If the aim of the study was to analyse diversity of PFGE profiles of E. coli O157 in a faecal sample following isolation by the IMS/CT-SMAC technique, at least five colonies per sample should be analysed to detect different PFGE subtypes if present.
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Affiliation(s)
- L Vali
- Molecular Chemotherapy, Centre for Infectious Diseases, University of Edinburgh, Edinburgh, UK
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20
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Halliday JEB, Chase-Topping ME, Pearce MC, McKendrick IJ, Allison L, Fenlon D, Low C, Mellor DJ, Gunn GJ, Woolhouse MEJ. Herd-level risk factors associated with the presence of Phage type 21/28 E. coli O157 on Scottish cattle farms. BMC Microbiol 2006; 6:99. [PMID: 17140453 PMCID: PMC1713242 DOI: 10.1186/1471-2180-6-99] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 12/02/2006] [Indexed: 11/10/2022] Open
Abstract
Background E. coli O157 is a bacterial pathogen that is shed by cattle and can cause severe disease in humans. Phage type (PT) 21/28 is a subtype of E. coli O157 that is found across Scotland and is associated with particularly severe human morbidity. Methods A cross-sectional survey of Scottish cattle farms was conducted in the period Feb 2002-Feb 2004 to determine the prevalence of E. coli O157 in cattle herds. Data from 88 farms on which E. coli O157 was present were analysed using generalised linear mixed models to identify risk factors for the presence of PT 21/28 specifically. Results The analysis identified private water supply, and northerly farm location as risk factors for PT 21/28 presence. There was a significant association between the presence of PT 21/28 and an increased number of E. coli O157 positive pat samples from a farm, and PT 21/28 was significantly associated with larger E. coli O157 counts than non-PT 21/28 E. coli O157. Conclusion PT 21/28 has significant risk factors that distinguish it from other phage types of E. coli O157. This finding has implications for the control of E. coli O157 as a whole and suggests that control could be tailored to target the locally dominant PT.
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Affiliation(s)
- Jo EB Halliday
- Centre for Infectious Diseases, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
| | - Margo E Chase-Topping
- Centre for Infectious Diseases, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh, EH9 3JF, UK
| | - Michael C Pearce
- Scottish Agricultural College, Animal Health Group, Research Division, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Iain J McKendrick
- Biomathematics & Statistics Scotland, King's Buildings, West Mains Road, Edinburgh, EH9 3JZ, UK
| | - Lesley Allison
- Scottish E. coli O157 Reference Laboratory, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Dave Fenlon
- Scottish Agricultural College, Animal Health Group, Research Division, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Chris Low
- Scottish Agricultural College, Animal Health Group, Research Division, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Dominic J Mellor
- Comparative Epidemiology & Informatics, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK
| | - George J Gunn
- Scottish Agricultural College, Animal Health Group, Research Division, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Mark EJ Woolhouse
- Centre for Infectious Diseases, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh, EH9 3JF, UK
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Hall LM, Evans J, Smith AW, Pearce MC, Knight HI, Foster G, Low JC, Gunn GJ. Sensitivity of an immunomagnetic-separation-based test for detecting Escherichia coli O26 in bovine feces. Appl Environ Microbiol 2006; 72:7260-3. [PMID: 16980429 PMCID: PMC1636212 DOI: 10.1128/aem.03028-05] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The sensitivity of a test for cattle shedding Escherichia coli serogroup O26 was estimated using several fecal pats artificially inoculated at a range of concentrations with different E. coli O26 strains. The test involves the enrichment of fecal microflora in buffered peptone water, the selective concentration of E. coli O26 using antibody-coated immunomagnetic-separation beads, the identification of E. coli colonies on Chromocult tryptone bile X-glucuronide agar, and confirmation of the serogroup with E. coli serogroup O26-specific antisera using slide agglutination. The effective dose of E. coli O26 for an 80% test sensitivity (ED(80)) was 1.0 x 10(4) CFU g(-1) feces (95% confidence interval, 4.7 x 10(3) to 2.4 x 10(4)). Differences in test sensitivity between different E. coli O26 strains and fecal pats were also observed. Individual estimates of ED(80) for each strain and fecal pat combination ranged from 4.2 x 10(2) to 4.8 x 10(5) CFU g(-1). These results suggest that the test is useful for identifying individuals shedding a large number of E. coli O26 organisms or, if an appropriate number of individuals in a herd are sampled, for identifying affected herds. The study also provides a benchmark estimate of sensitivity that can be used to compare alternative tests for E. coli O26 and a methodological approach that can be applied to tests for other pathogenic members of the Enterobacteriaceae and other sample types.
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Affiliation(s)
- L M Hall
- Scottish Agricultural College, Stratherrick Rd., Inverness IV2 4JZ, United Kingdom.
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Matthews L, Low JC, Gally DL, Pearce MC, Mellor DJ, Heesterbeek JAP, Chase-Topping M, Naylor SW, Shaw DJ, Reid SWJ, Gunn GJ, Woolhouse MEJ. Heterogeneous shedding of Escherichia coli O157 in cattle and its implications for control. Proc Natl Acad Sci U S A 2006; 103:547-52. [PMID: 16407143 PMCID: PMC1325964 DOI: 10.1073/pnas.0503776103] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Identification of the relative importance of within- and between-host variability in infectiousness and the impact of these heterogeneities on the transmission dynamics of infectious agents can enable efficient targeting of control measures. Cattle, a major reservoir host for the zoonotic pathogen Escherichia coli O157, are known to exhibit a high degree of heterogeneity in bacterial shedding densities. By relating bacterial count to infectiousness and fitting dynamic epidemiological models to prevalence data from a cross-sectional survey of cattle farms in Scotland, we identify a robust pattern: approximately 80% of the transmission arises from the 20% most infectious individuals. We examine potential control options under a range of assumptions about within- and between-host variability in infection dynamics. Our results show that the within-herd basic reproduction ratio, R(0), could be reduced to <1 with targeted measures aimed at preventing infection in the 5% of individuals with the highest overall infectiousness. Alternatively, interventions such as vaccination or the use of probiotics that aim to reduce bacterial carriage could produce dramatic reductions in R(0) by preventing carriage at concentrations corresponding to the top few percent of the observed range of counts. We conclude that a greater understanding of the cause of the heterogeneity in bacterial carriage could lead to highly efficient control measures to reduce the prevalence of E. coli O157.
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Affiliation(s)
- L Matthews
- Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, United Kingdom.
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Pearce MC, Evans J, McKendrick IJ, Smith AW, Knight HI, Mellor DJ, Woolhouse MEJ, Gunn GJ, Low JC. Prevalence and virulence factors of Escherichia coli serogroups O26, O103, O111, and O145 shed by cattle in Scotland. Appl Environ Microbiol 2006; 72:653-9. [PMID: 16391103 PMCID: PMC1352218 DOI: 10.1128/aem.72.1.653-659.2006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Accepted: 11/02/2005] [Indexed: 01/01/2023] Open
Abstract
A national survey was conducted to determine the prevalence of Escherichia coli O26, O103, O111, and O145 in feces of Scottish cattle. In total, 6,086 fecal pats from 338 farms were tested. The weighted mean percentages of farms on which shedding was detected were 23% for E. coli O26, 22% for E. coli O103, and 10% for E. coli O145. The weighted mean prevalences in fecal pats were 4.6% for E. coli O26, 2.7% for E. coli O103, and 0.7% for E. coli O145. No E. coli O111 was detected. Farms with cattle shedding E. coli serogroup O26, O103, or O145 were widely dispersed across Scotland and were identified most often in summer and autumn. However, on individual farms, fecal shedding of E. coli O26, O103, or O145 was frequently undetectable or the numbers of pats testing positive were small. For serogroup O26 or O103 there was clustering of positive pats within management groups, and the presence of an animal shedding one of these serogroups was a positive predictor for shedding by others, suggesting local transmission of infection. Carriage of vtx was rare in E. coli O103 and O145 isolates, but 49.0% of E. coli O26 isolates possessed vtx, invariably vtx1 alone or vtx1 and vtx2 together. The carriage of eae and ehxA genes was highly associated in all three serogroups. Among E. coli serogroup O26 isolates, 28.9% carried vtx, eae, and ehxA-a profile consistent with E. coli O26 strains known to cause human disease.
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Affiliation(s)
- M C Pearce
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Roslin, Midlothian EH25 9RG, United Kingdom
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Liu WC, Jenkins C, Shaw DJ, Matthews L, Pearce MC, Low JC, Gunn GJ, Smith HR, Frankel G, Woolhouse MEJ. Modelling the epidemiology of Verocytotoxin-producing Escherichia coli serogroups in young calves. Epidemiol Infect 2005; 133:449-58. [PMID: 15962551 PMCID: PMC2870268 DOI: 10.1017/s0950268804003644] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We investigate the epidemiology of 12 Verocytotoxin-producing Escherichia coli (VTEC) serogroups observed in a calf cohort on a Scottish beef farm. Fitting mathematical models to the observed time-course of infections reveals that there is significant calf-to-calf transmission of VTEC. Our models suggest that 40% of all detected infections are from calf-to-calf transmission and 60% from other sources. Variation in the rates at which infected animals recover from infection by different VTEC serogroups appears to be important. Two thirds of the observed VTEC serogroups are lost from infected calves within 1 day of infection, while the rest persist for more than 3 days. Our study has demonstrated that VTEC are transmissible between calves and are typically lost from infected animals in less than 1 week. We suggest that future field studies may wish to adopt a tighter sampling frame in order to detect all circulating VTEC serogroups in similar animal populations.
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Affiliation(s)
- W C Liu
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian, Scotland, EH25 9RG, UK.
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Vali L, Pearce MC, Wisely KA, Hamouda A, Knight HI, Smith AW, Amyes SGB. Comparison of diversities of Escherichia coli O157 shed from a cohort of spring-born beef calves at pasture and in housing. Appl Environ Microbiol 2005; 71:1648-52. [PMID: 15746371 PMCID: PMC1065151 DOI: 10.1128/aem.71.3.1648-1652.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A cohort of spring-born beef calves demonstrated limited genetic and phenotypic diversity of Escherichia coli O157 when kept in a state of isolation. Despite this, there was a difference in the pulsed-field gel electrophoresis and phage types of isolates shed by cattle at pasture compared with those shed by the same cattle when weaned and housed.
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Affiliation(s)
- Leila Vali
- Medical Microbiology, University of Edinburgh, Medical School, Teviot Place, Edinburgh EH8 9AG, United Kingdom
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Shaw DJ, Jenkins C, Pearce MC, Cheasty T, Gunn GJ, Dougan G, Smith HR, Woolhouse MEJ, Frankel G. Shedding patterns of verocytotoxin-producing Escherichia coli strains in a cohort of calves and their dams on a Scottish beef farm. Appl Environ Microbiol 2005; 70:7456-65. [PMID: 15574948 PMCID: PMC535143 DOI: 10.1128/aem.70.12.7456-7465.2004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rectal fecal samples were taken once a week from 49 calves on the same farm. In addition, the dams of the calves were sampled at the time of calf birth and at the end of the study. Strains of verocytotoxin-producing Escherichia coli (VTEC) were isolated from these samples by using PCR and DNA probe hybridization tests and were characterized with respect to serotype, verocytotoxin gene (vtx) type, and the presence of the intimin (eae) and hemolysin (ehxA) genes. A total of 170 VTEC strains were isolated during 21 weeks from 130 (20%) of 664 samples from calves and from 40 (47%) of 86 samples from their dams. The characteristics of the calf strains differed from those strains isolated from the dams with respect to verocytotoxin 2 and the presence of the eae gene. In addition, no calf shed the same VTEC serogroup (excluding O?) as its dam at birth or at the end of the study. The most frequently detected serogroups in calves were serogroup O26 and provisional serogroup E40874 (VTEC O26 was found in 25 calves), whereas in dams serogroup O91 and provisional serogroup E54071 were the most common serogroups. VTEC O26 shedding appeared to be associated with very young calves and declined as the calves aged, whereas VTEC O2 shedding was associated with housing of the animals. VTEC O26 strains from calves were characterized by the presence of the vtx1, eae, and ehxA genes, whereas vtx2 was associated with VTEC O2 and provisional serogroup E40874. The high prevalence of VTEC O26 and of VTEC strains harboring the eae gene in this calf cohort is notable because of the association of the O26 serogroup and the presence of the eae gene with human disease. No association between calf diarrhea and any of the VTEC serogroups was identified.
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Affiliation(s)
- D J Shaw
- Veterinary Epidemiology Group, Centre for Tropical and Veterinary Medicine, College of Medicine and Veterinary Medicine, University of Edinburgh, Roslin, Midlothian, United Kingdom.
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Hoyle DV, Shaw DJ, Knight HI, Davison HC, Pearce MC, Low JC, Gunn GJ, Woolhouse MEJ. Age-related decline in carriage of ampicillin-resistant Escherichia coli in young calves. Appl Environ Microbiol 2004; 70:6927-30. [PMID: 15528566 PMCID: PMC525229 DOI: 10.1128/aem.70.11.6927-6930.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Accepted: 06/29/2004] [Indexed: 11/20/2022] Open
Abstract
The presence of ampicillin-resistant Escherichia coli (Amp(r) E. coli) in the fecal flora of calves was monitored on a monthly basis in seven cohorts of calves. Calves were rapidly colonized by Amp(r) E. coli, with peak prevalence in cohort calves observed in the 4 months after the calves were born. The prevalence of calves yielding Amp(r) E. coli in cohorts consistently declined to low levels with increasing age of the calves (P < 0.001).
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Affiliation(s)
- Deborah V Hoyle
- Centre for Tropical Veterinary Medicine, Roayl (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian, United Kingdom.
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Pearce MC, Fenlon D, Low JC, Smith AW, Knight HI, Evans J, Foster G, Synge BA, Gunn GJ. Distribution of Escherichia coli O157 in bovine fecal pats and its impact on estimates of the prevalence of fecal shedding. Appl Environ Microbiol 2004; 70:5737-43. [PMID: 15466508 PMCID: PMC522064 DOI: 10.1128/aem.70.10.5737-5743.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Accepted: 05/31/2004] [Indexed: 11/20/2022] Open
Abstract
The distribution of Escherichia coli O157 in bovine feces was examined by testing multiple samples from fecal pats and determining the density of E. coli O157 in immunomagnetic separation (IMS)-positive fecal samples. The density of E. coli O157 in bovine feces was highly variable, differing by as much as 76,800 CFU g(-1) between samples from the same fecal pat. The density in most positive samples was <100 CFU g(-1), the limit of reliable detection by IMS. Testing only one 1-g sample of feces per pat with IMS may result in a sensitivity of detection as low as 20 to 50%. It is therefore probable that most surveys have greatly underestimated the prevalence of E. coli O157 shedding in cattle and the proportion of farms with shedding cattle. The sensitivity of the detection of E. coli O157 in bovine feces can be as much as doubled by testing two 1-g samples per pat rather than one 1-g sample.
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Affiliation(s)
- M C Pearce
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Midlothian, UK.
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Vali L, Wisely KA, Pearce MC, Turner EJ, Knight HI, Smith AW, Amyes SGB. High-level genotypic variation and antibiotic sensitivity among Escherichia coli O157 strains isolated from two Scottish beef cattle farms. Appl Environ Microbiol 2004; 70:5947-54. [PMID: 15466537 PMCID: PMC522067 DOI: 10.1128/aem.70.10.5947-5954.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 05/31/2004] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli O157:H7 is a human pathogen that is carried and transmitted by cattle. Scotland is known to have one of the highest rates of E. coli O157 human infections in the world. Two hundred ninety-three isolates were obtained from naturally infected cattle and the environment on two farms in the Scottish Highlands. The isolates were typed by pulsed-field gel electrophoresis (PFGE) with XbaI restriction endonuclease enzyme, and 19 different variations in patterns were found. There was considerable genomic diversity within the E. coli O157 population on the two farms. The PFGE pattern of one of the observed subtypes matched exactly with that of a strain obtained from a Scottish patient with hemolytic-uremic syndrome. To examine the stability of an individual E. coli O157 strain, continuous subculturing of a strain was performed 110 times. No variation from the original PFGE pattern was observed. We found three indistinguishable subtypes of E. coli O157 on both study farms, suggesting common sources of infection. We also examined the antibiotic resistance of the isolated strains. Phenotypic studies demonstrated resistance of the strains to sulfamethoxazole (100%), chloramphenicol (3.07%), and at a lower rate, other antibiotics, indicating the preservation of antibiotic sensitivity in a rapidly changing population of E. coli O157.
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Affiliation(s)
- Leila Vali
- Medical Microbiology, University of Edinburgh, Medical School, Teviot Place, Edinburgh EH8 9AG, UK
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Yates CM, Pearce MC, Woolhouse MEJ, Amyes SGB. High frequency transfer and horizontal spread of apramycin resistance in calf faecal Escherichia coli. J Antimicrob Chemother 2004; 54:534-7. [PMID: 15231771 DOI: 10.1093/jac/dkh353] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES The aminoglycoside apramycin has been used extensively in animal husbandry in the UK since 1978. This study aimed to determine both whether calves that had never been treated with aminoglycoside antibiotics harboured apramycin-resistant (apr(R)) commensal Escherichia coli, and the mode of spread of the resistance gene. METHODS Apr(R) E. coli from weekly calf faecal samples were typed by pulsed-field gel electrophoresis, antibiotic resistance phenotype, plasmid restriction profiles and plasmid transfer frequencies. RESULTS During 4 months of weekly sampling, six of 11 calves were found to harbour apr(R) E. coli. All apr(R) E. coli (45) were cross-resistant to gentamicin and tobramycin, which are both used in human medicine. Resistance was conferred by the aac(3)IV gene, present on three different conjugative plasmids. Two of these plasmids also mediated tetracycline and streptomycin resistance. One plasmid demonstrated very high transfer frequencies and was found in three different genotypes. CONCLUSIONS We report the presence of apr(R) commensal E. coli in cattle that have never been treated with aminoglycosides. The presence of one conjugative plasmid in three different genotypes is evidence of horizontal spread of this plasmid. This is the first report of a very high transfer frequency of apr(R) plasmid, demonstrating horizontal spread in the commensal flora of food animals.
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Affiliation(s)
- C M Yates
- Medical Microbiology, University of Edinburgh Medical School, Edinburgh EH8 9AG, UK.
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Hoyle DV, Knight HI, Shaw DJ, Hillman K, Pearce MC, Low JC, Gunn GJ, Woolhouse MEJ. Acquisition and epidemiology of antibiotic-resistant Escherichia coli in a cohort of newborn calves. J Antimicrob Chemother 2004; 53:867-71. [PMID: 15056641 DOI: 10.1093/jac/dkh177] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The acquisition of antibiotic-resistant commensal Escherichia coli was examined in a cohort of newborn calves. METHODS Faecal samples were collected weekly from calves over a 4 month period and screened for E. coli resistant to ampicillin, apramycin and nalidixic acid at concentrations of 16, 8 and 8 mg/L, respectively. E. coli viable counts were performed on samples from a subset of calves. RESULTS All calves acquired ampicillin- and nalidixic acid-resistant E. coli, while only 67% acquired apramycin-resistant E. coli during the study. Sixty-seven per cent of samples were resistant to at least one of the three antibiotics. Prevalence of ampicillin and nalidixic acid resistance was high initially and declined significantly with age (P < 0.001). No temporal or age-related pattern was observed in the prevalence of apramycin resistance. Housing the cohort had a significant effect on the prevalence of nalidixic acid resistance (P < 0.001). Total and ampicillin- and nalidixic acid-resistant E. coli counts declined with calf age (P < 0.001), with the rate of decline in ampicillin-resistant counts being greater than that for total counts (P < 0.001). The proportion of total E. coli counts that were resistant to ampicillin or nalidixic acid also declined with age (P < 0.001). CONCLUSIONS Cohort calves rapidly acquired antibiotic-resistant bacteria within days of birth. Carriage of resistant bacteria was associated with both age and housing status of the cohort.
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Affiliation(s)
- Deborah V Hoyle
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG
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Pearce MC, Jenkins C, Vali L, Smith AW, Knight HI, Cheasty T, Smith HR, Gunn GJ, Woolhouse MEJ, Amyes SGB, Frankel G. Temporal shedding patterns and virulence factors of Escherichia coli serogroups O26, O103, O111, O145, and O157 in a cohort of beef calves and their dams. Appl Environ Microbiol 2004; 70:1708-16. [PMID: 15006796 PMCID: PMC368277 DOI: 10.1128/aem.70.3.1708-1716.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Accepted: 10/08/2003] [Indexed: 01/04/2023] Open
Abstract
This study investigated the shedding of Escherichia coli O26, O103, O111, O145, and O157 in a cohort of beef calves from birth over a 5-month period and assessed the relationship between shedding in calves and shedding in their dams, the relationship between shedding and scouring in calves, and the effect of housing on shedding in calves. Fecal samples were tested by immunomagnetic separation and by PCR and DNA hybridization assays. E. coli O26 was shed by 94% of calves. Over 90% of E. coli O26 isolates carried the vtx(1), eae, and ehl genes, 6.5% carried vtx(1) and vtx(2), and one isolate carried vtx(2) only. Serogroup O26 isolates comprised seven pulsed-field gel electrophoresis (PFGE) patterns but were dominated by one pattern which represented 85.7% of isolates. E. coli O103 was shed by 51% of calves. Forty-eight percent of E. coli O103 isolates carried eae and ehl, 2% carried vtx(2), and none carried vtx(1). Serogroup O103 isolates comprised 10 PFGE patterns and were dominated by two patterns representing 62.5% of isolates. Shedding of E. coli O145 and O157 was rare. All serogroup O145 isolates carried eae, but none carried vtx(1) or vtx(2). All but one serogroup O157 isolate carried vtx(2), eae, and ehl. E. coli O111 was not detected. In most calves, the temporal pattern of E. coli O26 and O103 shedding was random. E. coli O26 was detected in three times as many samples as E. coli O103, and the rate at which calves began shedding E. coli O26 for the first time was five times greater than that for E. coli O103. For E. coli O26, O103, and O157, there was no association between shedding by calves and shedding by dams within 1 week of birth. For E. coli O26 and O103, there was no association between shedding and scouring, and there was no significant change in shedding following housing.
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Affiliation(s)
- M C Pearce
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Roslin, Midlothian EH25 9RG, United Kingdom.
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Jenkins C, Pearce MC, Smith AW, Knight HI, Shaw DJ, Cheasty T, Foster G, Gunn GJ, Dougan G, Smith HR, Frankel G. Detection of Escherichia coli serogroups O26, O103, O111 and O145 from bovine faeces using immunomagnetic separation and PCR/DNA probe techniques. Lett Appl Microbiol 2003; 37:207-12. [PMID: 12904221 DOI: 10.1046/j.1472-765x.2003.01379.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AIMS The aim of this study was to isolate Escherichia coli O26, O103, O111 and O145 from 745 samples of bovine faeces using (i) immunomagnetic separation (IMS) beads coated with antibodies to lipopolysaccharide, and slide agglutination (SA) tests and (ii) PCR and DNA probes for the detection of the Verocytotoxin (VT) genes. METHODS AND RESULTS IMS-SA tests detected 132 isolates of presumptive E. coli O26, 112 (85%) were confirmed as serogroup O26 and 102 had the VT genes. One hundred and twenty-two strains of presumptive E. coli O103 were isolated by IMS-SA, 45 (37%) were confirmed as serogroup O103 but only one of these strains was identified as Verocytotoxin-producing E. coli (VTEC). Using the PCR/DNA probe method, 40 strains of VTEC O26 and three strains of VTEC O103 were isolated. IMS-SA identified 21 strains of presumptive E. coli O145, of which only four (19%) were confirmed as serogroup O145. VTEC of this serogroup was not detected by either IMS-SA or PCR/DNA probes. E. coli O111 was not isolated by either method. CONCLUSION IMS beads were 2.5 times more sensitive than PCR/DNA probe methods for the detection of VTEC O26 in bovine faeces. SIGNIFICANCE AND IMPACT OF THE STUDY IMS-SA is a sensitive method for detecting specific E. coli serogroups. However, the specificity of this method would be enhanced by the introduction of selective media and the use of tube agglutination tests for confirmation of the preliminary SA results.
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Affiliation(s)
- C Jenkins
- Laboratory of Enteric Pathogens, Health Protection Agency, 61 Colindale Avenue, London, NW9 5HT, UK.
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Jenkins C, Pearce MC, Chart H, Cheasty T, Willshaw GA, Gunn GJ, Dougan G, Smith HR, Synge BA, Frankel G. An eight-month study of a population of verocytotoxigenic Escherichia coli (VTEC) in a Scottish cattle herd. J Appl Microbiol 2003; 93:944-53. [PMID: 12452950 DOI: 10.1046/j.1365-2672.2002.01771.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Strains of Verocytotoxin-producing Escherichia coli (VTEC) from Scottish beef cattle on the same farm were isolated during four visits over a period of eight months. Characteristics of these strains were examined to allow comparisons with strains of VTEC associated with human infection. METHODS AND RESULTS Strains were characterized to investigate the relationship between these bovine isolates with respect to serotype, Verocytotoxin (VT) type, intimin-type, and presence or absence of the enterohaemolysin genes. VT genes were detected in 176 of 710 (25%) faecal samples tested using PCR, although only 94 (13%) VTEC strains were isolated using DNA probes on cultures. Forty-five different serotypes were detected. Commonly isolated serotypes included O128ab:H8, O26:H11 and O113:H21. VTEC O26:H11 and O113:H21 have been associated with human disease. Strains harbouring the VT2 genes were most frequently isolated during the first three visits to the farm and those with both VT1 and VT2 genes were the major type during the final visit. Of the 94 strains of non-O157 VTEC isolated, 16 (17%) had the intimin gene; nine had the gene encoding beta-intimin and seven strains had an eta/zeta-intimin gene. Forty-one (44%) of 94 strains carried enterohaemolysin genes. CONCLUSIONS Different serotypes and certain transmissible characteristics, such as VT-type and the enterohaemolysin phenotype, appeared to be common throughout the VTEC population at different times. SIGNIFICANCE AND IMPACT OF THE STUDY Detailed typing and subtyping strains of VTEC as described in this study may improve our understanding of the relationship between bovine VTEC and those found in the human population.
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Affiliation(s)
- C Jenkins
- Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK
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Gally DL, Naylor SW, Low JC, Gunn GJ, Synge BA, Pearce MC, Donachie W, Besser TE. Colonisation site of E coli O157 in cattle. Vet Rec 2003; 152:307. [PMID: 12650483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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Naylor SW, Low JC, Besser TE, Mahajan A, Gunn GJ, Pearce MC, McKendrick IJ, Smith DGE, Gally DL. Lymphoid follicle-dense mucosa at the terminal rectum is the principal site of colonization of enterohemorrhagic Escherichia coli O157:H7 in the bovine host. Infect Immun 2003; 71:1505-12. [PMID: 12595469 PMCID: PMC148874 DOI: 10.1128/iai.71.3.1505-1512.2003] [Citation(s) in RCA: 422] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli O157:H7 causes bloody diarrhea and potentially fatal systemic sequelae in humans. Cattle are most frequently identified as the primary source of infection, and E. coli O157:H7 generally colonizes the gastrointestinal tracts of cattle without causing disease. In this study, persistence and tropism were assessed for four different E. coli O157:H7 strains. Experimentally infected calves shed the organism for at least 14 days prior to necropsy. For the majority of these animals, as well as for a naturally colonized animal obtained from a commercial beef farm, the highest numbers of E. coli O157:H7 were found in the feces, with negative or significantly lower levels detected in lumen contents taken from the gastrointestinal tract. Detailed examination demonstrated that in these individuals the majority of tissue-associated bacteria were adherent to mucosal epithelium within a defined region extending up to 5 cm proximally from the recto-anal junction. The tissue targeted by E. coli O157:H7 was characterized by a high density of lymphoid follicles. Microcolonies of the bacterium were readily detected on the epithelium of this region by immunofluorescence microscopy. As a consequence of this specific distribution, E. coli O157:H7 was present predominantly on the surface of the fecal stool. In contrast, other E. coli serotypes were present at consistent levels throughout the large intestine and were equally distributed in the stool. This is a novel tropism that may enhance dissemination both between animals and from animals to humans. The accessibility of this site may facilitate simple intervention strategies.
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Affiliation(s)
- Stuart W Naylor
- Zoonotic and Animal Pathogens Research Laboratory, Medical Microbiology, Edinburgh University, Edinburgh, EH8 9AG, United Kingdom
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Chart H, Pearce MC, Mellor D, Shaw DJ, Brown D. Immunoassays to detect the serum antibody response of cattle to infection with Salmonella Typhimurium definitive type 104 and following vaccination with Bovivac S. J Appl Microbiol 2002; 93:46-51. [PMID: 12067373 DOI: 10.1046/j.1365-2672.2002.01653.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To use ELISA and immunoblotting assays to examine the serum antibody response of cattle infected with Salmonella Typhimurium DT104 and following vaccination with Bovivac S. METHODS AND RESULTS Three hundred and twenty-nine cattle, including 16 shedding multiresistant Salmonella Typhimurium DT104, were screened for serum antibodies binding to O=1, 4, 5, 12 lipopolysaccharide (LPS) antigens before and after vaccination with Bovivac S. Sera with an ELISA reading of 0.9A405 or above were shown to contain antibodies, of the IgG-class only, to the LPS of Salmonella Typhimurium using immunoblotting. Prior to vaccination, only 11 cattle had serum IgG-class antibodies to the O=4, 5 LPS antigens, and of these one also had antibodies to outer membrane proteins and H=i flagellar antigens. Following vaccination, 87 out of 315 cattle developed serum antibodies to the LPS of Salmonella Typhimurium. CONCLUSIONS Evidence of infection of cattle with Salmonella Typhimurium was readily obtained with an LPS-based ELISA in association with an immunoblotting procedure, supplementing existing bacteriological procedures. This enabled the detection of an increase in the number of cattle with serum antibodies to Salmonella Typhimurium LPS following vaccination with Bovivac S. SIGNIFICANCE AND IMPACT OF THE STUDY The immunoassays described provided evidence of infection with Salmonella Typhimurium and served as a valuable adjunct to established bacteriology.
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Affiliation(s)
- H Chart
- Laboratory of Enteric Pathogens, Division of Gastrointestinal Infections, Central Public Health Laboratory, London, UK.
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Jenkins C, Chart H, Cheasty T, Willshaw GA, Pearce MC, Foster G, Gunn GJ, Smith HR, Dougan G, Synge BA, Frankel G. Verocytotoxin-producing Escherichia coli (VTEC) other than serogroup O157 from Scottish cattle. Vet Rec 2002; 151:58-60. [PMID: 12148605 DOI: 10.1136/vr.151.2.58] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- C Jenkins
- Laboratory of Enteric Pathogens, Central Public Health Authority, London
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Abstract
Serpins are the prototypical members of the conformational disease family, a group of proteins that undergoes a change in shape that subsequently leads to tissue deposition. One specific example is alpha(1)-antichymotrypsin (ACT), which undergoes misfolding and aggregation that has been implicated in emphysema and Alzheimer's disease. In this study we have used guanidine hydrochloride (GdnHCl)-induced denaturation to investigate the conformational changes involved in the folding and unfolding of ACT. When the reaction was followed by circular dichroism spectroscopy, one stable intermediate was observed in 1.5 m GdnHCl. The same experiment monitored by fluorescence revealed a second intermediate formed in 2.5 m GdnHCl. Both these intermediates bound the hydrophobic dye ANS. These data suggest a four-state model for ACT folding N <--> I(1) <--> I(2) <--> U. I(1) and I(2) both have a similar loss of secondary structure (20%) compared with the native state. In I(2), however, there is a significant loss of tertiary interactions as revealed by changes in fluorescence emission maximum and intensity. Kinetic analysis of the unfolding reaction indicated that the native state is unstable with a fast rate of unfolding in water of 0.4 s(-1). The implications of these data for both ACT function and associated diseases are discussed.
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Affiliation(s)
- M C Pearce
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
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Pearce MC, Sheridan JW, Jones DM, Lawrence GW, Murphy DM, Masutti B, McCosker C, Douglas V, George D, O'Keefe A. Control of group C meningococcal disease in Australian aboriginal children by mass rifampicin chemoprophylaxis and vaccination. Lancet 1995; 346:20-3. [PMID: 7603139 DOI: 10.1016/s0140-6736(95)92651-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An outbreak of 12 cases of meningitis, 11 caused by Neisseria meningitidis serogroup C, occurred at Doomadgee from September, 1990, to April, 1991. The incidence of meningitis was 17.55/10(3) person-years. Only children aged 1-10 years were affected. In October, 1990, or shortly thereafter, 473/509 children aged between 1 and 15 years inclusive had one dose of Mencevax AC. From the time of vaccination until April, 1991, a further eight cases occurred, six in vaccinated children. Vaccine efficacy in 1-15 year olds was calculated as 77%. Despite this, in April, 1991, the prevalence of antibody to group C polysaccharide in vaccinated children (78%) was not significantly different from that in unvaccinated children and adults. 46 nonresponders were revaccinated, and, in February, 1992, 78% had antibodies to group C polysaccharide. In April, 1991, an estimated 3.0% of the population had group C organisms, carriage being directly related to household crowding. In June, 1991, 2 months after mass prophylaxis with rifampicin, none of these individuals were carriers. In October, 1991, the carriage rate of group C organisms was 0.64%. There have been no further cases caused by the epidemic strain. Although uncrowded housing is a basic need, mass chemoprophylaxis and two doses of vaccine for children should be used in similar outbreaks.
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Affiliation(s)
- M C Pearce
- Communicable Diseases Branch, Queensland Health, Brisbane, Australia
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Abstract
OBJECTIVE To investigate treatment patterns for malaria and the use of Australian guidelines which were then current for the treatment of malaria in Queensland in 1992. DESIGN AND PARTICIPANTS A review of patient treatment and demographic details, obtained from the treating doctor by questionnaire, for all cases of malaria in Queensland in 1992 which were reported to Queensland Health (316 people treated for 341 episodes of malaria). RESULTS Plasmodium falciparum infections were treated according to the recommendations in the guidelines in 20% of cases. Thirty-five per cent of infections were treated with chloroquine, even though most of these were acquired in countries where chloroquine or chloroquine/antifolate-resistant P. falciparum malaria existed. Plasmodium vivax infections were treated with the recommended course of chloroquine in 58% of cases. Fifty per cent of patients with P. vivax infection were treated with primaquine, but only 57% of these received the dose recommended in the guidelines for the eradication of hypnozoites. Patterns of malaria treatment were basically similar in the malaria-receptive zone and elsewhere in Queensland, although P. falciparum infections in the receptive zone were treated according to the guidelines at a higher rate (32%) than in the rest of Queensland (13%). CONCLUSION In 1992, many cases of malaria in Queensland were not treated according to the recommendations in the Australian malaria treatment guidelines. We suggest that improved distribution of simple but comprehensive guidelines for malaria treatment may assist medical practitioners in the provision of prompt, effective treatment, and help prevent the reestablishment of endemic malaria in Australia.
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Affiliation(s)
- B J McCall
- Communicable Diseases Branch, Queensland Health, Brisbane
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