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Hudson DT, Chapman PA, Day RC, Morgan XC, Beck CW. Complete Genome Sequences of Kinneretia sp. Strain XES5, Shinella sp. Strain XGS7, and Vogesella sp. Strain XCS3, Isolated from Xenopus laevis Skin. Microbiol Resour Announc 2021; 10:e0105021. [PMID: 34913717 PMCID: PMC8675264 DOI: 10.1128/mra.01050-21] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/29/2021] [Indexed: 11/20/2022] Open
Abstract
Here, we report the genome sequences of three bacterial isolates, Kinneretia sp. strain XES5, Shinella sp. strain XGS7, and Vogesella sp. strain XCS3, which were cultured from skin of adult female laboratory-bred Xenopus laevis.
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Affiliation(s)
- D. T. Hudson
- Department of Zoology, University of Otago, Dunedin, New Zealand
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - P. A. Chapman
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - R. C. Day
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - X. C. Morgan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - C. W. Beck
- Department of Zoology, University of Otago, Dunedin, New Zealand
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Webb DP, Wildey KB, Chapman PA. A comparison of permethrin and methomyl insecticides for the control of a multiresistant strain of houseflies (Musca domestica). ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780270103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Numbers of Escherichia coli O157 in food may be low and sensitive techniques are therefore needed for its detection. The objectives of this study were to use carcass meat samples artificially inoculated with various strains of E. coli O157 to compare the sensitivity of enrichment in three different media and to compare immunomagnetic separation followed by culture of magnetic beads to cefixime tellurite sorbitol MacConkey agar with three immunoassays for the detection of E. coli O157 in the enrichment cultures. Duplicate 250, 25 and 2-3 CFU of each of 16 strains of E. coli O157 added to 25-g samples of beef carcass meat were used to compare the sensitivity of (1) enrichment in supplemented tryptone soya broth (sTSB), Reveal 8-h and Reveal 20-h media, and (2) immunomagnetic separation and culture to cefixime tellurite sorbitol MacConkey agar (IMS/CT-SMAC) with Reveal, VIP and STAT immunoassays for detecting the organism. An initial inoculum of 250 CFU/25 g meat was detected in all 32 samples by IMS/CT-SMAC performed on all enrichment media and by Reveal performed on Reveal 8-h and Reveal 20-h media, but in only 30, 19 and 9 samples by Reveal, VIP and STAT, respectively, performed on sTSB medium. An initial inoculum of 25 CFU/25 g meat was detected in 28, 32 and 30 of 32 samples by IMS/CT-SMAC performed on sTSB, Reveal 8-h and Reveal 20-h media, respectively, and in 32 and 30 samples by Reveal performed on Reveal 8-h and Reveal 20-h media, but in only 22, 11 and 2 samples by Reveal, VIP and STAT, respectively, performed on sTSB medium. An initial inoculum of 2-3 CFU/25 g meat was detected in 25, 31 and 28 of 32 samples by IMS/CT-SMAC performed on sTSB, Reveal 8-h and Reveal 20-h media, respectively, and in 25 and 23 samples by Reveal performed on Reveal 8-h and Reveal 20-h media, but in only 14, 1 and 0 samples by Reveal, VIP and STAT, respectively, performed on sTSB medium.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Herries Road, S5 7BQ Sheffield, UK.
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Abstract
In the first documented outbreak of HC caused by Escherichia coli O157, which occurred in the North-west USA in 1982, there was a strong association between infection and prior consumption of ground beef from a chain of fast food restaurants. Foods of bovine origin, including beef, milk and dairy products, have since been implicated in many outbreaks of infection world-wide. Investigations during the course of outbreaks, or at random, have shown that cattle are a major reservoir of E. coli O157. E. coli O157 was isolated from cattle at slaughter in Sheffield in 1987, this being the first isolation from cattle in the UK. Following a cluster of cases in May/June 1992, an abattoir study showed the organism to be present in 4% of cattle at slaughter and on up to a third of carcasses from rectal swab-positive animals. E. coli O157 was isolated from a food source (unpasteurized milk), for the first time in the UK, in Sheffield in May 1993. During surveillance in 1995-6, E. coli O157 was isolated from 15.7% of cattle, with a monthly prevalence which varied from 5 to 37%. E. coli O157 was also isolated from 2.2% of sheep. During surveillance in 1996, E. coli O157 was isolated from 5.9% of samples of lamb products and from 1.5% of samples of beef products, despite the prevalence in cattle being much higher than in sheep. Work is in progress to try to explain this higher prevalence in lamb products. During 1997 in Sheffield, the only cases of E. coli O157 for which a confirmed source was established were associated with direct animal contact on farm visits. During on-farm investigations of these cases, E. coli O157 was isolated from faecal samples from adult cattle, calves, three different breeds of sheep, two different breeds of pigs, goats and a pony.
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Chapman PA, Ellin M, Ashton R, Shafique W. Comparison of culture, PCR and immunoassays for detecting Escherichia coli O157 following enrichment culture and immunomagnetic separation performed on naturally contaminated raw meat products. Int J Food Microbiol 2001; 68:11-20. [PMID: 11545210 DOI: 10.1016/s0168-1605(01)00464-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [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: 11/25/2022]
Abstract
The aims of this study were (i) to evaluate the specificity and sensitivity of three previously described PCR assays for the detection of Escherichia coli O157 and, (ii) to compare PCR, culture, and two visual immunoassays (VIAs), BioSign and Path-Stik, for detecting E. coli O157 after enrichment culture and immunomagnetic separation (IMS) performed on various naturally contaminated raw beef, lamb and mixed meat products. Twelve sorbitol nonfermenting (SNF) verocytotoxin-producing (VT +) E. coli O157, 6 SNF VT - E. coli O157, 4 sorbitol fermenting (SF) VT + E. coli O157, 3 SF VT - E. coli O157, 23 E. coli belonging to 17 other serogroups and 12 organisms of other species were used to check the specificity of PCR reactions. Only one primer pair generated amplimers only with E. coli O157 and was used for all subsequent work. After enrichment culture and on inoculated minced beef samples, PCR was as sensitive as culture for detecting 9 of the 12 strains of E. coli O157, but up to 4 log10 more sensitive than culture for detecting three strains. Of the 120 samples of naturally contaminated meat products examined, 80 (67%) were positive by PCR, 70 (58%) were positive by BioSign, 69 (58%) were positive by culture and 67 (56%) were positive by Path-Stik. Although both VIAs lacked sensitivity when compared to PCR, both compared favourably with culture and both were extremely rapid and easy to perform, giving a result in less than 15 min. Eleven samples were positive by PCR and both VIAs, but negative by culture because culture plates were heavily overgrown with SF organisms, making detection of any E. coli O157 present impossible.
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Abstract
A field survey was performed in a heifer raising operation in Northern Italy to study the introduction, maintenance and dissemination of Escherichia coli O157 in the herd and to identify possible control measures at the farm level. Rectal swabs from two different groups of animals (surveys 1 and 2) were tested for E. coli O157 by an immunomagnetic separation technique. In survey 1, a group of female calves (341 animals initially) introduced from 30 dairy herds during April 1996 to March 1997 were tested for E. coli O157 on arrival from the original herd when housed in individual hutches, 2-3 days after completion of weaning (which was associated with grouping) and 2 months after weaning. No statistically significant difference between excretion rates (3.8%, 4.2%, 4.4%, respectively) was found. Calves from which E. coli O157 was isolated on arrival came from 6 of the 30 dairy herds. Strains isolated during survey 1 belonged to seven different pulsed field gel electrophoresis (PFGE) profiles. In survey 2, a group of young animals aged, at the beginning of the study, between 2 1/2 and 7 1/2 months (median = 124 days) was tested monthly for E. coli O157 for 11-15 months from May 1996 to July 1997. The group included 92 animals for 11 months and then gradually decreased to 59 animals. Overall, E. coli O157, belonging to six different PFGE profiles, were isolated from 138 (10.7%) of 1293 rectal swabs. Monthly excretion rates ranged from 2.7% to 23.7%, with summer peaks in both years. Fifty-nine (64.1%) of the 92 heifers were positive at least once: of these 59 animals, 22 (37.3%) were positive on only one occasion, 23 (39%) were positive on two occasions and 14 (23.7%) were positive on three or more occasions. From two heifers positive on 9 out of the 15 sampling visits, strains with the same PFGE profile were isolated, respectively, on seven and eight occasions while strains with only one band difference were isolated on the remaining occasions. E. coli O157 was also isolated from 6 of 16 samples of bedding, two of two samples of slurry and one of five samples from water troughs collected during survey 2.
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Affiliation(s)
- G Conedera
- Istituto Zooprofilattico delle Venezie, Cordenons (PN), Italy.
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Chapman PA, Ellin M, Ashton R. A comparison of immunomagnetic separation and culture, Reveal and VIP for the detection of E. coli O157 in enrichment cultures of naturally-contaminated raw beef, lamb and mixed meat products. Lett Appl Microbiol 2001; 32:171-5. [PMID: 11264747 DOI: 10.1046/j.1472-765x.2001.00883.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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: 11/20/2022]
Abstract
AIMS The aims of this study were (i) to evaluate the specificity and sensitivity of three previously described PCR assays for the detection of E. coli O157 and, (ii) to compare PCR, culture, and two visual immunoassays (VIAs), BioSign and Path-Stik, for detecting E. coli O157 after enrichment culture and immunomagnetic separation (IMS) performed on various naturally contaminated raw beef, lamb and mixed meat products. METHODS AND RESULTS Twelve sorbitol non fermenting (SNF) verocytotoxin-producing (VT+) E. coli O157, 6 SNF VT- E. coli O157, 4 sorbitol fermenting (SF) VT+ E. coli O157, 3 SF VT- E. coli O157, 23 E. coli belonging to 17 other serogroups and 12 organisms of other species were used to check the specificity of PCR reactions. Only one primer pair generated amplimers only with E. coli O157 and was used for all subsequent work. After enrichment culture and on inoculated minced beef samples, PCR was as sensitive as culture for detecting 9 of the 12 strains of E. coli O157, but up to 4 log10 more sensitive than culture for detecting three strains. Of the 120 samples of naturally contaminated meat products examined, 80 (67%) were positive by PCR, 70 (58%) were positive by BioSign, 69 (58%) were positive by culture and 67 (56%) were positive by Path-Stik. Eleven samples were positive by PCR and both VIAs, but negative by culture because culture plates were heavily overgrown with SF organisms making detection of any E. coli O157 present impossible. CONCLUSIONS PCR and both VIAs compared well with culture of beads to CT-SMAC for detecting E. coli O157 after enrichment culture and IMS. PCR appeared to be the most sensitive method, but needed specialised equipment and was also the most expensive, laborious and technically demanding technique. Although lacking the sensitivity of PCR, the VIAs were of comparable sensitivity to culture and were extremely quick and easy to perform giving a result in less than 15 minutes. SIGNIFICANCE AND IMPACT OF THE STUDY Culture techniques may fail to detect E. coli O157 retrieved by IMS due to overgrowth with other organisms.
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Chapman PA, Cerdán Malo AT, Ellin M, Ashton R. Escherichia coli O157 in cattle and sheep at slaughter, on beef and lamb carcasses and in raw beef and lamb products in South Yorkshire, UK. Int J Food Microbiol 2001; 64:139-50. [PMID: 11252496 DOI: 10.1016/s0168-1605(00)00453-0] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [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: 11/30/2022]
Abstract
A 1 year study of Escherichia coli O157 in cattle and sheep at slaughter, on beef and lamb carcasses and in raw beef and lamb products from retail butchers' shops was performed in the Sheffield area. Each month, samples of rectal faeces were collected immediately after slaughter from 400 cattle and 600 sheep, and 400-430 samples of raw meat products were purchased from butchers' shops. Meat samples were also obtained from 1500 beef and 1500 lamb carcasses. All samples were examined for E. coli O157 by enrichment culture, immunomagnetic separation and culture of magnetic particles onto cefixime tellurite sorbitol MacConkey agar. Raw meat products were also examined for numbers of generic E. coli by a standard membrane culture method. E. coli O157 was isolated from 620 (12.9%) of 4800 cattle, 100 (7.4%) of 7200 sheep, 21 (1.4%) of 1500 beef carcasses, 10 (0.7%) of 1500 lamb carcasses and from 22 (0.44%) of 4983 raw meat products. E. coli O157 was isolated more frequently from lamb products (0.8%) than from beef products (0.4%). Numbers of generic E. coli in meat products reached seasonal peaks in July and August with counts of > 10(4)/g occurring more frequently in lamb products (50.8 and 42.4%, respectively) than in beef products (19.3 and 23.8%, respectively). The majority of E. coli O157 strains, from animals, carcasses and meat samples, were isolated during the summer. Most were verocytotoxigenic as determined by Vero cell assay and DNA hybridisation, eaeA gene positive and contained a 92 kb plasmid. The isolates were compared with 66 isolates from human cases over the same period. A combination of phage type, toxin genotype and plasmid analysis allowed subdivision of all the E. coli O157 isolates into 96 subtypes. Of these subtypes, 53 (55%) were isolated only from bovine faecal samples. However, 61 (92%) of the 66 isolates from humans belonged to 13 subtypes which were also found in the animal population.
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Abstract
Two cases of Escherichia coli O157 infection occurred in children after visiting an inner city open farm. Subsequently faecal samples collected from animal pens and samples of composted mixed animal manure and vegetable waste were examined for E. coli O157 by enrichment culture, immunomagnetic separation and culture of magnetic beads to cefixime tellurite sorbitol MacConkey agar. Strains of E. coli O157 were characterized by hybridization with DNA probes for VT1, VT2 and eaeA, plasmid profile analysis, phage typing and pulsed field gel electrophoresis (PFGE). Verocytotoxin-producing E. coli O157 strains were isolated from faecal samples from a cow, a horse, 3 breeds of pigs, 2 breeds of sheep and 2 breeds of goats and from 2 samples of compost which had been processed for 3 months. All strains were phage type 21, hybridized with probes for VT2 and eaeA but not with one for VT1, harboured 92 and 2 kb plasmids and gave indistinguishable banding patterns with PFGE. Although only two culture-confirmed cases of infection had been identified, the farm had over 100,000 visitors per year and so it was closed as a precaution both to allow a thorough investigation and to prevent further cases. The investigation identified many factors which may have contributed to transmission of E. coli O157 infection. Most of these were readily resolved by appropriate corrective measures and as there were no further cases associated with the farm during the ensuing 4 weeks it then re-opened. These cases highlight the risk, especially to young children, of acquiring zoonotic infections during visits to open farms and emphasize the need for adequate guidance and supervision before and during such visits.
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Abstract
Between April 1996 and March 1997 we examined 5093 samples of raw beef and lamb products for the presence of E. coli O157. Samples were purchased from 81 small butchers' shops in south Yorkshire. In March 1997 we also examined five samples of dried mint for the presence of E. coli O157. Strains of E. coli O157 were isolated by enrichment culture in modified buffered peptone water followed by immunomagnetic separation and culture of magnetic beads onto cefixime tellurite sorbitol MacConkey agar. Strains were characterized by phage typing, toxin genotyping and plasmid analysis. Strains of E. coli O157 were isolated from 72 (1.4%) of 5093 samples; it was isolated from 36 (1.1%) of 3216 samples of beef products and from 29 (2.9%) samples of lamb products. The highest prevalence was found in lamb sausages and lamb burgers where E. coli O157 was isolated from 3 (4.1%) of 73 and 18 (3.7%) of 484 samples respectively. Strains of E. coli O157 were isolated most frequently during early summer. Strains of E. coli O157 were also isolated from 2 of 5 samples of dried mint although we did not determine how the mint had become contaminated. All isolates of E. coli O157 were Verocytotoxin-producing as determined by both Vero cell assay and DNA hybridization for the genes encoding Verocytotoxin and all were positive for the eaeA gene. A combination of phage typing, toxin genotyping and plasmid profile subdivided the 72 strains of E. coli isolated into 20 different subtypes, of which 18 were indistinguishable from strains isolated previously from cattle and sheep; of these 18 strains, 8 were indistinguishable from strains isolated from human cases of infection during the study period.
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O'Sullivan JP, Chapman PA, Jenkins L, Smith R. Characteristics of high grade dyskaryotic cervical smears likely to be missed on rapid rescreening. Acta Cytol 2000; 44:37-40. [PMID: 10667157 DOI: 10.1159/000326222] [Citation(s) in RCA: 13] [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: 11/19/2022]
Abstract
OBJECTIVE To determine if there is a type of high grade dyskaryotic cervical smear that is likely to be missed on rapid rescreening. STUDY DESIGN Fifty high grade dyskaryotic smears that had originally been incorrectly reported as negative (FN) were admixed with 100 true negative smears. Each smear in the set was rapidly reviewed at least 40 times. The FN smears that were picked out on > 50% of screenings were compared with those that were passed as unremarkable on > 50% of screenings for features of the dyskaryotic cell population. RESULTS Significant differences between the two types of FN smear were present in five aspects of the dyskaryotic cell population. A FN smear is more likely to be missed on rapid rescreening than to be selected for review if it has few dyskaryotic cells; if the dyskaryotic cells are small, with pale nuclei; and if they are scattered singly rather than in groups or syncytia. CONCLUSION A type of severely dyskaryotic smear is likely to evade rapid rescreening as well as routine screening. This suggests that even when rapid rescreening is used as a quality assurance measure, the "zero-error standard" is unlikely to be attained.
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Affiliation(s)
- J P O'Sullivan
- Department of Cytopathology, St. Richard's Hospital, Chichester, West Sussex, U.K
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O'Sullivan JP, Chapman PA, Jenkins L, Smith R. Variables involved in rapid review. Cytopathology 1999; 10:144-5. [PMID: 10211623] [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: 02/12/2023]
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Chapman PA. Escherichia coliMechanisms of Virulence. J Antimicrob Chemother 1999. [DOI: 10.1093/jac/43.3.437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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O'Sullivan JP, A'Hern RP, Chapman PA, Jenkins L, Smith R, al-Nafussi A, Brett MT, Herbert A, McKean ME, Waddell CA. A case-control study of true-positive versus false-negative cervical smears in women with cervical intraepithelial neoplasia (CIN) III. Cytopathology 1998; 9:155-61. [PMID: 9638376 DOI: 10.1046/j.1365-2303.1998.00155.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [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: 11/20/2022]
Abstract
Cervical smears (n = 150) from five departments showing high-grade dyskaryosis were examined by three cytologists. All the smears came from patients with biopsy-proven CIN III. One hundred had been correctly reported (true positives) but 50 had originally been reported as negative and had been found to be positive only on review (false negatives). There were significant differences between the two sets in the characteristics of the dyskaryotic cell population. The false-negative smears tended to have fewer than 200 dyskaryotic cells. The nuclei of the dyskaryotic cells tended to have fine rather than coarse nuclear chromatin. A smear with fewer than 50 dyskaryotic cells is 26 times more likely to be reported as negative than one with more than 200 dyskaryotic cells. The results suggest that there is a type of severely dyskaryotic smear that is inherently likely to be missed on routine screening.
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Affiliation(s)
- J P O'Sullivan
- Department of Histopathology, St Richard's Hospital, Chichester, UK
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Abstract
Samples of rectal faeces were collected immediately after slaughter from 400 cattle each month for a 1-year period and from 1000 each of sheep, pigs and poultry over the same period. Samples were examined for Escherichia coli O157 by enrichment culture in buffered peptone water with vancomycin, cefixime and cefsulodin followed by immunomagnetic separation and culture of magnetic particles onto cefixime tellurite sorbitol MacConkey agar. E. coli O157 was isolated from 752 (15.7%) of 4800 cattle, 22 (2.2%) of 1000 sheep and from 4 (0.4%) of 1000 pigs, but not from any of 1000 chickens. Of the cattle sampled. 1840 (38.4%) were prime beef animals, 1661 (34.6%) were dairy animals being culled and the status could not be determined for the other 1299 (27%) animals. E. coli O157 was found in 246 (13.4%) of the 1840 beef cattle and 268 (16.1%) of the 1661 dairy cattle. The monthly prevalence of E. coli O157 in cattle was 4.8-36.8% and was at its highest in spring and late summer. Seventeen of the 22 isolates from sheep were also made over the summer period. All E. coli O157 isolates from sheep and 749 (99.6%) of the 752 E. coli O157 isolates from cattle were verocytotoxigenic as determined by Vero cell assay and DNA hybridization, eaeA gene positive, contained a 92 kb plasmid and were thus typical of strains causing infections in man. In contrast isolates from pigs were non-toxigenic, eaeA gene negative and did not contain a 92 kb plasmid and would, therefore, be unlikely to be a source of infection for man.
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Chapman PA, Siddons CA, Manning J, Cheetham C. An outbreak of infection due to verocytotoxin-producing Escherichia coli O157 in four families: the influence of laboratory methods on the outcome of the investigation. Epidemiol Infect 1997; 119:113-9. [PMID: 9363008 PMCID: PMC2808831 DOI: 10.1017/s0950268897007991] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [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: 02/05/2023] Open
Abstract
Three members of family A, who had diarrhoea on 20 October, lived on a small arable farm which had 10 cattle. Manure from the animals was used to fertilize the ground for growing potatoes which were then offered for retail sale, unwashed, directly from the farm. The mother from family B bought potatoes, which were covered with manure, from family A in early November and over the subsequent 10 days she became ill with diarrhoea and her daughter and son both became ill with bloody diarrhoea. The mother from family C visited family B while the daughter from the latter family was symptomatic; the mother developed diarrhoea several days later. The mother and two sons from family D visited family B while the son from the latter family was symptomatic; the first son developed bloody diarrhoea 6 days later which progressed to development of haemolytic-uraemic syndrome. Direct culture of faecal samples onto cefixime rhamnose sorbitol MacConkey agar failed to isolate E. coli O157 from any of the symptomatic patients, and direct culture onto cefixime tellurite sorbitol MacConkey agar isolated the organism from only one patient. In contrast, a combination of isolation of E. coli O157 by immunomagnetic separation and detection of E. coli O157-specific secretory IgA, suggested E. coli O157 infection in all eight symptomatic patients, but not in any of the family members who were not ill. Two children who excreted the organism for 60 and 89 days respectively were the only two patients who did not develop a secretory IgA response. E. coli O157 was not isolated from potatoes from the farm and faecal samples from the farm animals were not available for examination. The study illustrates the need to use the most sensitive methods available during the investigation and follow up of cases of E. coli O157 infection.
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Chapman PA, Ackroyd HJ. Farmed deer as a potential source of verocytotoxin-producing Escherichia coli O157. Vet Rec 1997; 141:314-5. [PMID: 9330481] [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: 02/05/2023]
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Wight JP, Rhodes P, Chapman PA, Lee SM, Finner P. Outbreaks of food poisoning in adults due to Escherichia coli O111 and campylobacter associated with coach trips to northern France. Epidemiol Infect 1997; 119:9-14. [PMID: 9287937 PMCID: PMC2808816 DOI: 10.1017/s0950268897007620] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 02/05/2023] Open
Abstract
Thirty-seven out of 48 people on a coach excursion to northern France developed gastrointestinal symptoms within 4 days of the trip. Twenty-six had stool samples positive for Escherichia coli O111, 8 were also positive for Campylobacter species, and 1 was positive for campylobacter alone. Strains of E. coli were positive for the effacing and attaching protein (eaeA) gene, but negative for other E. coli virulence genes, and therefore belonged to the enteropathogenic E. coli (EPEC) group. Twenty-two out of 37 people in a second party which followed the same itinerary 2 weeks later also became ill. One had a stool sample positive for E. coli O111. Analytical epidemiology suggested that the source of infections was a restaurant in northern France at which both parties had eaten.
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Conedera G, Marangon S, Chapman PA, Zuin A, Caprioli A. Atypical strains of verocytotoxin-producing Escherichia coli O157 in beef cattle at slaughter in Veneto region, Italy. Zentralbl Veterinarmed B 1997; 44:301-6. [PMID: 9270353 DOI: 10.1111/j.1439-0450.1997.tb00977.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cattle arriving for slaughter at abattoirs in the Veneto region of N. Italy were examined for intestinal carriage of Escherichia coli O157. Rectal swabs were cultured in modified buffered peptone water and E. coli O157 was concentrated by an immunomagnetic separation technique; the magnetic beads were cultured onto cefixime tellurite sorbitol MacConkey agar. Sorbitol non-fermenting E. coli O157 was isolated from 15 (3.6%) of 419 feedlot cattle but not from 437 veal calves or 65 culled cows. All strains of E. coli O157 hybridized with DNA probes specific for the VT1 or VT2 genes, but two strains did not produce toxin detectable by Vero cell assay. Six different plasmid profiles were observed with all strains harbouring the large 93 kb plasmid characteristic of VTEC. Six strains produced urease but otherwise strains were biochemically typical of E. coli O157. One strain was resistant to streptomycin, tetracycline and sulphonamides but the remainder were sensitive to all antimicrobials tested. This is the first description of the isolation of verocytotoxin-producing E. coli O157 from cattle in Italy. As the contamination of bovine carcasses with E. coli O157 during slaughter and processing has been demonstrated, the risk of transmission of this organism from beef cattle to the human population in the Veneto region, through foods of bovine origin or by other routes, should not be overlooked.
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Affiliation(s)
- G Conedera
- Istituto Zooprofilattico Sperimentale delle Venezie, Sezione di Pordenone, Rome, Italy
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Chapman PA, Malo AT, Siddons CA, Harkin M. Use of commercial enzyme immunoassays and immunomagnetic separation systems for detecting Escherichia coli O157 in bovine fecal samples. Appl Environ Microbiol 1997; 63:2549-53. [PMID: 9212405 PMCID: PMC168552 DOI: 10.1128/aem.63.7.2549-2553.1997] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.5] [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: 02/04/2023] Open
Abstract
A commercial enzyme immunoassay (EIA) (E. coli O157 Visual Immunoassay; Tecra Diagnostics) performed on enrichment cultures in modified Escherichia coli broth (mECn) was compared with immunomagnetic separation (IMS) (Dynabeads anti-E. coli O157; Dynal) performed on enrichment cultures in modified buffered peptone water (BPW-VCC) for the detection of E. coli O157 in bovine fecal samples. Tests on fecal suspensions inoculated with each of 12 different strains of E. coli O157 showed that both the EIA and IMS methods were 10- to 100-fold more sensitive than direct culture or enrichment subculture methods for detection of the organism. EIA and IMS were then compared for detection of E. coli O157 in bovine rectal swabs. For confirmation of positive EIA tests, a commercial system (Immunocapture System [ICS]; Tecra Diagnostics) was compared with IMS; both were performed on mECn enrichment cultures. Of 200 rectal swabs examined, 17 gave positive results in the EIA which were confirmed by both confirmation systems, 2 gave positive results in the EIA which were confirmed by IMS but not by ICS, and 1 gave a positive result in the EIA which was confirmed by ICS but not by IMS. Of these 20, 15 were also positive by the BPW-VCC-IMS culture system; a further 3 samples were positive by this culture system but gave a negative result in the EIA. Eight samples were negative by the BPW-VCC-IMS culture system but gave a positive result in the EIA which could not be confirmed by either confirmation system. Further examination of the eight unconfirmed EIA-positive samples yielded sorbitol-fermenting E. coli O157 from three samples. Of the remaining five cultures, four were positive in an EIA for verocytotoxins (VT) and two were positive in a cell culture assay for VT1. The remaining 170 samples were negative by both EIA and BPW-VCC-IMS. The Tecra EIA and IMS are both technically simple and sensitive methods for detecting E. coli O157 in bovine fecal samples. There was no statistically significant difference between the numbers of positives detected by the different assays (P = 0.29).
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Sheffield, United Kingdom
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Abstract
A dairy herd associated with Escherichia coli O157 infection in humans was studied for the 15 months following the outbreak to examine seasonal, age and management factors affecting faecal excretion of the organism and to determine the mode and frequency of milk contamination with the organism. Between May 1993 and July 1994, 28 visits were made to the farm to collect a total of 3593 rectal swabs from cows, heifers and calves and 329 milk samples. E. coli O157:H7 was isolated from 153 (4.3%) of 3593 bovine rectal swabs. The maximum prevalence at any one visit was 14% in lactating cows, 40% in non-lactating cows, 56% in calves and 68% in heifers. The prevalence in lactating cows, which was significantly lower than in the other groups, peaked during May-July 1993 and again briefly after the cattle were housed during November 1993 and then again during May 1994. Excretion rates of E. coli O157:H7 in lactating cows were highest during the first month after calving, falling during lactation and rising to another peak at 7 months postpartum. Between November 1993 and May 1994 there was no evidence of excretion in any group. Eighty-seven (74%) of the animals which excreted E. coli O157:H7 did so on only one occasion but 23 (32%) of 73 cows and heifers and 7 (16%) of 44 calves which excreted the organism did so on more than one occasion. E. coli O157:H7 was not isolated from milk taken from the bulk tank but it was isolated from individual milk samples (one milk jar and one fore-milk) from two animals previously shown to be faecal excretors of the organism. All isolates of E. coli O157:H7 obtained were of the same phage type, toxin genotype and plasmid profile.
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Affiliation(s)
- S C Mechie
- Thirsk Veterinary Investigation Centre, Thirsk
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Chapman PA, Siddons CA, Malo AT, Harkin MA. Lamb products as a potential source of E coli O157. Vet Rec 1996; 139:427-8. [PMID: 8923722] [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: 02/03/2023]
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Chapman PA, Siddons CA. A comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin-producing Escherichia coli O157 from cases of bloody diarrhoea, non-bloody diarrhoea and asymptomatic contacts. J Med Microbiol 1996; 44:267-71. [PMID: 8606354 DOI: 10.1099/00222615-44-4-267] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [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: 01/31/2023] Open
Abstract
Enrichment culture in modified buffered peptone water followed by immunomagnetic separation (IMS) with magnetic beads coated with an antibody against Escherichia coli O157 was compared with direct culture on cefixime rhamnose sorbitol MacConkey agar (CR-SMAC) and cefixime tellurite sorbitol MacConkey agar (CT-SMAC) for the isolation of E. coli O157 from human faeces. In total, 690 samples were examined; E. coli O157 was isolated from 25 samples by IMS but from only 15 and 12 by direct culture on CT-SMAC and CR-SMAC, respectively. The difference in sensitivity of detection was at its most marked on screening repeat faecal samples from known cases and samples from asymptomatic contacts, when of 12 strains of E. coli O157 isolated by IMS, only five were isolated by direct culture. IMS is a sensitive and simple technique for the isolation of E. coli O157 from human faecal samples and should prove useful in elucidating further the epidemiology of this micro-organism.
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Chapman PA, Siddons CA, Harkin MA. Sheep as a potential source of verocytotoxin-producing Escherichia coli O157. Vet Rec 1996; 138:23-4. [PMID: 8825332] [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: 02/02/2023]
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Abstract
Minced beef samples inoculated with Escherichia coli O157 were cultured in buffered peptone water supplemented with vancomycin, cefsulodin and cefixime (BPW-VCC) and subcultured to cefixime tellurite sorbitol MacConkey (CT-SMAC) agar both directly and after immunomagnetic separation (IMS) of the organism with magnetic beads coated with an antibody against E. coli O157 (Dynabeads anti-E. coli O157, Dynal, Oslo). E. coli O157 was recovered from initial inocula of 200 organisms/g by direct subculture and 2 organisms/g by IMS. Twelve strains of E. coli O157 of different combinations of phage type, H antigen and toxin genotype were all recovered from initial inocula of two organisms/g by IMS. Non-specific binding of other organisms to the magnetic beads could be reduced by washing of the beads in PBS with Tween-20 0.002-0.005% E. coli O157 was not bound by magnetic coated with an unrelated antibody. During investigation of a dairy herd that was possibly linked to a small outbreak of infection with E. coli O157, the organism was isolated from 2 of 279 forestream milk samples from individual cattle; both isolates were made only by the IMS technique. IMS is rapid, technically simple, and a specific method for isolation of E. coli O157 and will be useful in epidemiological studies.
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Chapman PA, Wright DJ, Siddons CA. A comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin-producing Escherichia coli O157 from bovine faeces. J Med Microbiol 1994; 40:424-7. [PMID: 8006935 DOI: 10.1099/00222615-40-6-424] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.5] [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: 01/28/2023] Open
Abstract
Enrichment culture (EC) in modified buffered peptone water followed by immunomagnetic separation (IMS) with magnetic beads coated with an antibody against Escherichia coli O157 (Dynabeads anti-E. coli O157; Dynal, Oslo) was compared with direct culture on cefixime rhamnose sorbitol MacConkey agar (CR-SMAC) and cefixime tellurite sorbitol MacConkey agar (CT-SMAC) for the isolation of E. coli O157 from bovine faeces. When used to examine bovine faecal suspensions inoculated with 12 different strains of E. coli O157, EC-IMS was c. 100-fold more sensitive for detection of the organism than direct culture on either medium. During monitoring of a dairy herd, E. coli O157 was isolated from 84 (8.2%) of 1024 rectal swabs taken from cattle over a 4-month period; 23 (27.4% of the 84 strains were isolated by both direct culture and IMS (15 of the 23 were isolated on both media, five on CT-SMAC only and three on CR-SMAC only), whereas 61 (72.6%) strains were isolated by IMS only. IMS is a sensitive and simple technique for the isolation of E. coli O157 from bovine faecal samples and should prove useful in elucidating further the epidemiology of this organism.
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Abstract
Cases of culture-confirmed clinically typical haemorrhagic colitis caused by verocytotoxin-producing (VT+) Escherichia coli O157 and age- and sex-matched control patients were examined for antibodies to E. coli O157. Serum samples from 28 cases and 34 patients in control group 1 were examined for VT1- and VT2-neutralising antibodies, E. coli O157 agglutinating antibodies, and by an enzyme immunoassay (EIA) technique for IgG antibodies against smooth lipopolysaccharide purified from E. coli O157 and for IgG antibodies against whole intact E. coli O157 cells. Differences between antibody titres were significant when compared by a Wilcoxon two-sample test for E. coli O157 agglutinating antibodies (p < 0.05) and IgG antibodies against whole cells (p < 0.001). The whole-cell EIA was used further to examine faecal samples from 93 cases and 47 patients in control group 2 for IgA antibodies. Elevated levels of faecal IgA specific for E. coli O157 were found in 59 (63.4%) of 93 cases but in only 10 (21.2%) of 47 control patients (p < 0.001); follow-up faecal samples from five cases all showed marked rises in levels of IgA that appeared to coincide with cessation of excretion of the organism. Detection of specific faecal IgA with a whole-cell EIA, although requiring further evaluation, may be a useful addition to tests currently available for the diagnosis of infection by VT+ E. coli O157.
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Chapman PA, Siddons CA, Wright DJ, Norman P, Fox J, Crick E. Cattle as a possible source of verocytotoxin-producing Escherichia coli O157 infections in man. Epidemiol Infect 1993; 111:439-47. [PMID: 8270004 PMCID: PMC2271261 DOI: 10.1017/s0950268800057162] [Citation(s) in RCA: 285] [Impact Index Per Article: 9.2] [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: 01/29/2023] Open
Abstract
In May-June 1992 cases of infection with verocytotoxin-producing (VT+) Escherichia coli O157 in South Yorkshire could have been associated with prior consumption of beef from a local abattoir. During investigation of the abattoir, bovine rectal swabs and samples of meat and surface swabs from beef carcasses were examined for E. coli O157, isolates of which were tested for toxigenicity, plasmid content and phage type. E. coli O157 was isolated from 84 (4%) of 2103 bovine rectal swabs; of these 84, 78 (93%) were VT+, the most common phage types being 2 and 8, the types implicated in the cluster of human cases. Positive cattle were from diverse sources within England. E. coli O157 was isolated from 7 (30%) of 23 carcasses of rectal swab-positive cattle and from 2 (8%) of 25 carcasses of rectal swab-negative cattle. The study has shown that cattle may be a reservoir of VT+ E. coli O157, and that contamination of carcasses during slaughter and processing may be how beef and beef products become contaminated and thereby transmit the organism to man.
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Abstract
Potassium tellurite was assessed for the selection of verocytotoxigenic (VT+) Escherichia coli O157. MICs were higher for VT+ E. coli O157 than for other strains of E. coli and for Aeromonas spp. MacConkey medium containing sorbitol, tellurite and cefixime (TC-SMAC) permitted the growth of VT+ E. coli O157 and Shigella sonnei but partially or completely inhibited the growth of 67% of other strains of E. coli and all or most strains of other sorbitol-non-fermenting species tested. Of 391 rectal swabs from cattle screened on TC-SMAC medium, 26 yielded isolates of VT+ E. coli O157 whereas sorbitol-MacConkey medium with cefixime and rhamnose yielded only nine isolates. Inclusion of potassium tellurite in sorbitol-MacConkey agar markedly increased the rate of isolation of VT+ E. coli O157 from cattle rectal swabs and may do so for other types of specimen.
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Siddons CA, Chapman PA. Detection of faecal IgA in the diagnosis of infection by Escherichia coli O157. J Infect 1993; 26:343-4. [PMID: 8505578 DOI: 10.1016/0163-4453(93)96051-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Abstract
AIMS To evaluate a digoxigenin-labelled trivalent DNA probe (LT, ST1a, ST1b) for detecting enterotoxigenic Escherichia coli (ETEC), by comparison with a cell culture assay for detecting LT, individual DNA probes for LT, ST1a and ST1b, and an enzyme immunoassay for detecting ST1. METHODS A 1268 base pair DNA fragment, containing parts of the genes for E coli heat labile enterotoxin (LT) and heat stable enterotoxins (ST1a and ST1b), was random prime labelled with digoxigenin-dUTP. The labelled DNA was used as a probe in colony hybridisation reactions to examine 180 E coli strains of which 92 had previously been shown by a cell culture assay to produce LT. Six LT negative ST1 positive E coli, 34 Verotoxin producing E coli (VTEC), and 84 organisms from other genera were also examined. All organisms other than VTEC were isolated from travellers returning from abroad with diarrhoea. All E coli strains were retested by cell culture for LT, and were tested by enzyme immunoassay (EIA) for ST1, and by the trivalent and individual DNA probes. RESULTS All 81 isolates, that on retesting by cell culture were positive for LT, also hybridised with the trivalent and LT probes; 27 of these were also enzyme immunoassay (EIA) positive for ST1 of which 24 hybridised with the ST1b probe and three with the ST1a probe. Of 99 isolates, that on retesting by cell culture were negative for LT, all were negative by LT probe and only three were EIA positive for ST1; these three were positive by both trivalent and ST1b probes. Four isolates were positive by the trivalent probe but negative by cell culture and EIA; all four were positive by ST1b probe. Compared with the cell culture assay for LT, the probe had a sensitivity and specificity both of 100%; compared with the EIA for ST1, the probe had a sensitivity of 100% and specificity of 88%. CONCLUSIONS The trivalent DNA probe is a sensitive, specific, and reliable method for detecting ETEC that should be considered for use by diagnostic microbiology laboratories.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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McGoogan E, Chapman PA. The British Society for Clinical Cytology Certificate of Competence in Cytology Screening: a report of the first 3 years' experience. Cytopathology 1992; 3:311-6. [PMID: 1288656 DOI: 10.1111/j.1365-2303.1992.tb00053.x] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In 1988 the Department of Health (DOH) recognized the cytology screener grade of laboratory staff. Cytology screeners have a 2 year training period after which they must sit a 'competence examination'. The British Society for Clinical Cytology offers an examination to meet the DOH specification. It consists of a written paper, a practical screening test, a spot test and a short viva voce. The screening test is paramount and candidates who miss a dyskaryotic smear cannot be successful. In the first 3 years there have been 22 examinations, 294 candidates and a pass rate of 76%. The majority of candidates were Cytology Screeners of 2-3 years experience but significant numbers of Medical Laboratory Scientific Officers (MLSOs) and senior MLSOs also chose to sit the examination.
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Affiliation(s)
- E McGoogan
- Department of Pathology, University of Edinburgh Medical School, UK
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36
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Abstract
AIMS To evaluate a commercially available enzyme immunoassay based on a monoclonal antibody to a genus specific Cryptosporidium (IDEIA Cryptosporidium; Dako) antigen for detecting Cryptosporidium oocysts in faecal and environmental samples. METHODS 435 human faecal samples and post-filtration deposits from 10 reservoir samples, and from six tap water samples seeded with Cryptosporidium oocysts, were examined by EIA according to the manufacturer's instructions, and by microscopic examination of phenolauramine stained smears. Samples giving discrepant results were examined by specific immunofluorescence, before and after concentration of oocysts. RESULTS Sixteen (3.6%) faecal samples were positive by both microscopy and EIA; five (1.1%) were positive by microscopy of auramine-phenol stained smears (but were not confirmed by specific immunofluorescence) and negative by EIA; one (0.2%) was positive by EIA alone, but confirmed by specific immunofluorescence; and 362 (83.2%) were negative by both microscopy and EIA. Compared with immunofluorescence positive faecal samples, the sensitivity of conventional microscopy and EIA were 94% and 100%, and specificity 76.4% and 100%, respectively. Fifty one (11.7%) were not examined by microscopy due to detection of other pathogens in a previous sample from that patient, but were found to be negative by EIA. Ten reservoir water samples (not suspected of being linked to cases of cryptosporidiosis) were negative by both microscopy and EIA. Of six samples of tap water seeded with varying concentrations of Cryptosporidium oocysts, two (10(2) and 10(3) oocysts/l) were positive by both microscopy and EIA, two (10 and 1/l) by EIA alone, and two (0.1/l and unseeded water) were negative by both microscopy and EIA. CONCLUSIONS The kit is simple and rapid to use and offers a less subjective method than microscopy for detecting Cryptosporidium in faecal samples submitted to a busy diagnostic laboratory.
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Affiliation(s)
- C A Siddons
- Public Health Laboratory, Northern General Hospital, Sheffield
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Joce RE, Bruce J, Kiely D, Noah ND, Dempster WB, Stalker R, Gumsley P, Chapman PA, Norman P, Watkins J. An outbreak of cryptosporidiosis associated with a swimming pool. Epidemiol Infect 1991; 107:497-508. [PMID: 1752299 PMCID: PMC2272100 DOI: 10.1017/s0950268800049190] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [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: 12/28/2022] Open
Abstract
In August 1988 an increase was noted in the number of cases of cryptosporidiosis identified by the microbiology laboratory at Doncaster Royal Infirmary. By 31 October, 67 cases had been reported. Preliminary investigations implicated the use of one of two swimming pools at a local sports centre and oocysts were identified in the pool water. Inspection of the pool revealed significant plumbing defects which had allowed ingress of sewage from the main sewer into the circulating pool water. Epidemiological investigation confirmed an association between head immersion and illness. The pools were closed when oocysts were identified in the water and extensive cleaning and repair work was undertaken. The pool water was retested for cryptosporidial oocysts and found to be negative before the pool reopened.
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Affiliation(s)
- R E Joce
- Public Health Laboratory Service Communicable Disease Surveillance Centre, London
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Abstract
Sorbitol-MacConkey medium has become widely used for the isolation of verotoxigenic (VT+) Escherichia coli O157. However, many organisms other than VT+ E. coli O157, especially other serogroups of E. coli and Proteus spp., may not ferment sorbitol, and thus may be confused initially with VT+ E. coli O157. Rhamnose is not fermented by VT+ E. coli O157, but is by most sorbitol non-fermenting E. coli of other serogroups. Cefixime is a cephalosporin antibiotic that is more active against Proteus spp. than against E. coli. Inclusion of rhamnose and cefixime in sorbitol-MacConkey agar improves its selectivity for the isolation of VT+ E. coli O157.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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39
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Abstract
Purified oocysts of Cryptosporidium were applied to the top of a sand filter which had been constructed in the laboratory. The filter was eluted with distilled water; fractions were collected and examined for Cryptosporidium by modified Ziehl-Neelsen technique and immunofluorescence microscopy and by an enzyme immunoassay. The results indicate that oocysts of Cryptosporidium do not easily pass through the sand filter, and that some disintegration of oocysts may occur during filtration.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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40
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Abstract
An enzyme immunoassay (EIA) with a monoclonal antibody to cryptosporidium oocysts was developed and evaluated for the examination of faecal and environmental samples. The EIA was as sensitive as microscopy for detecting Cryptosporidium but also produced some positive results which could not be confirmed by a modified Ziehl-Neelsen technique or by immunofluorescence microscopy. These specimens reacted also with heterologous antibodies in EIA, suggesting false positive results.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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Abstract
There was a marked peak in human cases of cryptosporidiosis in the Sheffield area in May and June 1986. Extensive epidemiological investigations failed to find a common source of food or a consistent history of animal contact, but did suggest that a waterborne outbreak of cryptosporidiosis may have occurred. Cryptosporidium oocysts were found in untreated water and in fish from a reservoir complex implicated by epidemiological analysis. Laboratory investigations confirmed that cattle on a farm adjacent to the reservoir complex were a possible source of contamination.
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Affiliation(s)
- B A Rush
- Public Health Laboratory, Northern General Hospital, Sheffield
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Humphrey TJ, Chapman PA, Rowe B, Gilbert RJ. A comparative study of the heat resistance of salmonellas in homogenized whole egg, egg yolk or albumen. Epidemiol Infect 1990; 104:237-41. [PMID: 2323357 PMCID: PMC2271751 DOI: 10.1017/s0950268800059409] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [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: 12/31/2022] Open
Abstract
Salmonella enteritidis PT4 was found to be more resistant to heat in egg than some other common egg-associated salmonellas. This organism was significantly more heat sensitive than S. senftenberg 775W, however, and should not survive in pasteurized liquid egg.
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Abstract
A commercial latex slide test (Oxoid DR 620) for the identification of Escherichia coli O157 was compared with a standard tube agglutination method using E coli O157 antiserum (Difco). Thirty isolates previously confirmed as E coli O157 were positive by both methods: 30 isolates of E coli of serogroups other than O157, 30 isolates of non-sorbitol fermenting organisms from various genera, and one isolate of E hermanii were all negative by both methods. It is concluded that the latex slide test offers a rapid and economical alternative to tube agglutination for the identification of E coli O157.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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Humphrey TJ, Greenwood M, Gilbert RJ, Rowe B, Chapman PA. The survival of salmonellas in shell eggs cooked under simulated domestic conditions. Epidemiol Infect 1989; 103:35-45. [PMID: 2673824 PMCID: PMC2249479 DOI: 10.1017/s0950268800030338] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.9] [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: 01/02/2023] Open
Abstract
Strains of Salmonella enteritidis, S. typhimurium and S. senftenberg inoculated into the yolks of shell eggs were found to survive forms of cooking where some of the yolk remained liquid. Survival was largely independent of the size of the initial inoculum. The organisms also grew rapidly in eggs stored at room temperature and after 2 days the number of cells per gram of yolk exceeded log10 8.0. With this level of contamination viable cells could be recovered from eggs cooked in any manner.
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Chapman PA, Wright DJ, Norman P. Role of verotoxin producing Escherichia coli in the aetiology of haemorrhagic colitis. J Clin Pathol 1989; 42:891-2. [PMID: 2671056 PMCID: PMC1142079 DOI: 10.1136/jcp.42.8.891-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- PA Chapman
- Public Health Laboratory, Northern General Hospital, Herries Road, Sheffield S5 7 AU
| | - DJ Wright
- Public Health Laboratory, Northern General Hospital, Herries Road, Sheffield S5 7 AU
| | - P Norman
- Public Health Laboratory, Northern General Hospital, Herries Road, Sheffield S5 7 AU
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Abstract
A commercial coagglutination assay (COA; Phadebact LT-ETEC) was compared with a Y1 mouse adrenal cell assay for detecting the heat labile enterotoxin of Escherichia coli. Of four different media evaluated for use with the COA, only one (modified blood agar) gave a positive result with all strains known to produce heat labile enterotoxin. With modified blood agar, the COA detected 74 (85%) of 87 such strains. Eighty six strains negative by cell culture assay were also negative by COA, and one strain positive by COA could not be confirmed by cell culture. The Phadebact LT-ETEC kit provides a simple, sensitive, and economical method for detecting E coli heat labile enterotoxin.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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Abstract
During 1986 and 1987, faecal samples from patients with haemorrhagic colitis (HC) or haemolytic-uraemic syndrome (HUS) were examined for evidence of infection by verotoxin-producing Escherichia coli (VTEC). During the 2-year period VTEC infections were found in 31 (78%) of 40 patients initially presenting with HC, and in 5 (63%) of 8 patients initially presenting with HUS. VTEC were found in only 2 (0.9%) of 229 age and sex matched control patients with acute non-bloody diarrhoea. All but one VTEC belonged to E. coli serogroup O 157. During 1987 this serogroup was isolated from 2 (1%) of 207 samples of faeces taken from cattle arriving at a Sheffield abattoir, indicating a possible source of these infections for man. We are unaware of previous reports of isolation of this organism from cattle in England.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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Chapman PA, Mitchelmore DL. A two-year survey of the incidence of heat-labile enterotoxin-producing Escherichia coli and other enteric pathogens in travellers returning to the Sheffield area. Epidemiol Infect 1988; 101:239-47. [PMID: 3053217 PMCID: PMC2249369 DOI: 10.1017/s0950268800054157] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 01/03/2023] Open
Abstract
A case-controlled study of the incidence of heat-labile enterotoxin-producing Escherichia coli (LT+ETEC) and other enteric pathogens in travellers returning to the Sheffield area was conducted from May 1984 to April 1986. LT+ETEC were found in 35 (5.8%) of 600 travellers to developed countries (mainly popular Mediterranean holiday resorts), 36 (11.3%) of 320 travellers to less-developed countries, and 11 (0.9%) of 1282 control patients whose illness was not associated with recent travel abroad. A seasonal peak of LT+ETEC infection was observed only in travellers to developed countries, with infections being significantly commoner in August to October. There was no significant deviation from expected age/sex distribution of LT+ETEC infection. Strains of LT+ETEC from travellers produced more toxin than strains from control patients, strains from travellers to less-developed countries producing most of all.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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Chapman PA, Rhodes P, Rylands W. Salmonella typhimurium phage type 141 infections in Sheffield during 1984 and 1985: association with hens' eggs. Epidemiol Infect 1988; 101:75-82. [PMID: 3042440 PMCID: PMC2249329 DOI: 10.1017/s095026880002923x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [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: 01/03/2023] Open
Abstract
Food poisoning due to Salmonella typhimurium phage type 141 was unusual in the Sheffield area before 1984. The sudden increase in incidence of this phage type during 1984 and 1985, and its causative role in several small outbreaks in this period have been investigated. Epidemiological and laboratory investigations suggested that hens' eggs were the most likely source of S. typhimurium phage type 141.
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Affiliation(s)
- P A Chapman
- Public Health Laboratory, Northern General Hospital, Sheffield
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