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P A Chapman - One of the best experts on this subject based on the ideXlab platform.
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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
International Journal of Food Microbiology, 2001Co-Authors: P A Chapman, A Cerdan T Malo, M Ellin, R Ashton, M A HarkinAbstract: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 >104/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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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
International Journal of Food Microbiology, 2001Co-Authors: P A Chapman, A Cerdan T Malo, M Ellin, R Ashton, M A HarkinAbstract: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 >104/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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infection with verocytotoxin producing escherichia coli o157 during a visit to an inner city open farm
Epidemiology and Infection, 2000Co-Authors: P A Chapman, J Cornell, C GreenAbstract: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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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
Epidemiology and Infection, 1997Co-Authors: P A Chapman, C A Siddons, J Manning, C CheethamAbstract: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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a 1 year study of escherichia coli o157 in cattle sheep pigs and poultry
Epidemiology and Infection, 1997Co-Authors: P A Chapman, C A Siddons, A Gerdan T Malo, M A HarkinAbstract: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.
Phillip I Tarr - One of the best experts on this subject based on the ideXlab platform.
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real time pcr assay for detection and differentiation of shiga toxin producing escherichia coli from clinical samples
Journal of Clinical Microbiology, 2015Co-Authors: Eileen J Klein, Jennifer R Stapp, Xuan Qin, Emmanouil Galanakis, Anita Thomas, Shannon Rich, Anne Marie Buccat, Phillip I TarrAbstract:Timely accurate diagnosis of Shiga toxin-producing Escherichia coli (STEC) infections is important. We evaluated a laboratory-developed real-time PCR (LD-PCR) assay targeting stx1, stx2, and rfbEO157 with 2,386 qualifying stool samples submitted to the microbiology laboratory of a tertiary care pediatric center between July 2011 and December 2013. Broth cultures of PCR-positive samples were tested for Shiga toxins by enzyme immunoassay (EIA) (ImmunoCard STAT! enterohemorrhagic E. coli [EHEC]; Meridian Bioscience) and cultured in attempts to recover both O157 and non-O157 STEC. E. coli O157 and non-O157 STEC were detected in 35 and 18 cases, respectively. Hemolytic uremic syndrome (HUS) occurred in 12 patients (10 infected with STEC O157, one infected with STEC O125ac, and one with PCR evidence of STEC but no resulting isolate). Among the 59 PCR-positive STEC specimens from 53 patients, only 29 (54.7%) of the associated specimens were toxin positive by EIA. LD-PCR differentiated STEC O157 from non-O157 using rfbEO157, and LD-PCR results prompted successful recovery of E. coli O157 (n = 25) and non-O157 STEC (n = 8) isolates, although the primary cultures and toxin assays were frequently negative. A rapid "mega"-multiplex PCR (FilmArray gastrointestinal panel; BioFire Diagnostics) was used retrospectively, and results correlated with LD-PCR findings in 25 (89%) of the 28 Sorbitol-MacConkey Agar culture-negative STEC cases. These findings demonstrate that PCR is more sensitive than EIA and/or culture and distinguishes between O157 and non-O157 STEC in clinical samples and that E. coli O157:H7 remains the predominant cause of HUS in our institution. PCR is highly recommended for rapid diagnosis of pediatric STEC infections.
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shiga toxin antigen detection should not replace sorbitol macconkey Agar screening of stool specimens
Journal of Clinical Microbiology, 2004Co-Authors: Eileen J Klein, Jennifer R Stapp, Marguerite A Neill, John M Besser, Michael T Osterholm, Phillip I Tarr, Richard B Thomson, Patrick J Gavin, Lance R PetersonAbstract:The interesting paper by Gavin et al., describing their experience using an enzyme immunoassay (EIA) to identify stools containing Shiga toxin (Stx)-producing Escherichia coli (STEC) (3), adds to the growing literature that non-O157:H7 STEC are overlooked pathogens. However, as physicians, clinical and public health microbiologists, and disease control epidemiologists, we are concerned by the authors' use of an EIA to screen stools and, only if this test is positive, to then seek E. coli O157:H7 with sorbitol MacConkey Agar culture (SMAC).
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comparison of escherichia coli o157 h7 antigen detection in stool and broth cultures to that in sorbitol macconkey Agar stool cultures
Journal of Clinical Microbiology, 2000Co-Authors: Jennifer R Stapp, Eileen J Klein, Srdjan Jelacic, Yoolee Yea, Marc Fischer, Carla R Clausen, Xuan Qin, David L Swerdlow, Phillip I TarrAbstract:We evaluated the Meridian IC-STAT direct fecal and broth culture antigen detection methods with samples from children infected with Escherichia coli O157:H7 and correlated the antigen detection results with the culture results. Stools of 16 children who had recently had stool cultures positive for this pathogen (population A) and 102 children with diarrhea of unknown cause (population B) were tested with the IC-STAT device (direct testing). Fecal broth cultures were also tested with this device (broth testing). The results were correlated to a standard of the combined yield from direct culture of stools on Sorbitol-MacConkey (SMAC) Agar and culture of broth on SMAC Agar. Eleven (69%) of the population A stool specimens yielded E. coli O157:H7 when plated directly on SMAC Agar. Two more specimens yielded this pathogen when the broth culture was similarly plated. Of these 13 stool specimens, 8 and 13 were positive by direct and broth testing (respective sensitivities, 62 and 100%). Compared to the sensitivity of a simultaneously performed SMAC Agar culture, the sensitivity of direct testing was 73%. Three (3%) of the population B stool specimens contained E. coli O157:H7 on SMAC Agar culture; one and three of these stool specimens were positive by direct and broth testing, respectively. The direct and broth IC-STAT tests were 100% specific with samples from children from population B. Direct IC-STAT testing of stools is rapid, easily performed, and specific but is insufficiently sensitive to exclude the possibility of infection with E. coli O157:H7. Performing the IC-STAT test with a broth culture increases its sensitivity. However, attempts to recover E. coli O157:H7 by culture should not be abandoned but, rather, should be increased when the IC-STAT test result is positive.
C A Siddons - One of the best experts on this subject based on the ideXlab platform.
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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
Epidemiology and Infection, 1997Co-Authors: P A Chapman, C A Siddons, J Manning, C CheethamAbstract: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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a 1 year study of escherichia coli o157 in cattle sheep pigs and poultry
Epidemiology and Infection, 1997Co-Authors: P A Chapman, C A Siddons, A Gerdan T Malo, M A HarkinAbstract: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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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
Journal of Medical Microbiology, 1996Co-Authors: P A Chapman, C A SiddonsAbstract:1058 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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a comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin producing escherichia coli 0157 from bovine faeces
Journal of Medical Microbiology, 1994Co-Authors: P A Chapman, D J Wright, C A SiddonsAbstract:Summary Enrichment culture (EC) in modified buffered peptone water followed by immunomagnetic separation (IMS) with magnetic beads coated with an antibody against Escherichia coli 0157 (Dynabeads anti-E. coli 0157; 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 0157 from bovine faeces. When used to examine bovine faecal suspensions inoculated with 12 different strains of E. coli 0157, 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 0157 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 0157 from bovine faecal samples and should prove useful in elucidating further the epidemiology of this organism.
Eileen J Klein - One of the best experts on this subject based on the ideXlab platform.
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real time pcr assay for detection and differentiation of shiga toxin producing escherichia coli from clinical samples
Journal of Clinical Microbiology, 2015Co-Authors: Eileen J Klein, Jennifer R Stapp, Xuan Qin, Emmanouil Galanakis, Anita Thomas, Shannon Rich, Anne Marie Buccat, Phillip I TarrAbstract:Timely accurate diagnosis of Shiga toxin-producing Escherichia coli (STEC) infections is important. We evaluated a laboratory-developed real-time PCR (LD-PCR) assay targeting stx1, stx2, and rfbEO157 with 2,386 qualifying stool samples submitted to the microbiology laboratory of a tertiary care pediatric center between July 2011 and December 2013. Broth cultures of PCR-positive samples were tested for Shiga toxins by enzyme immunoassay (EIA) (ImmunoCard STAT! enterohemorrhagic E. coli [EHEC]; Meridian Bioscience) and cultured in attempts to recover both O157 and non-O157 STEC. E. coli O157 and non-O157 STEC were detected in 35 and 18 cases, respectively. Hemolytic uremic syndrome (HUS) occurred in 12 patients (10 infected with STEC O157, one infected with STEC O125ac, and one with PCR evidence of STEC but no resulting isolate). Among the 59 PCR-positive STEC specimens from 53 patients, only 29 (54.7%) of the associated specimens were toxin positive by EIA. LD-PCR differentiated STEC O157 from non-O157 using rfbEO157, and LD-PCR results prompted successful recovery of E. coli O157 (n = 25) and non-O157 STEC (n = 8) isolates, although the primary cultures and toxin assays were frequently negative. A rapid "mega"-multiplex PCR (FilmArray gastrointestinal panel; BioFire Diagnostics) was used retrospectively, and results correlated with LD-PCR findings in 25 (89%) of the 28 Sorbitol-MacConkey Agar culture-negative STEC cases. These findings demonstrate that PCR is more sensitive than EIA and/or culture and distinguishes between O157 and non-O157 STEC in clinical samples and that E. coli O157:H7 remains the predominant cause of HUS in our institution. PCR is highly recommended for rapid diagnosis of pediatric STEC infections.
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shiga toxin antigen detection should not replace sorbitol macconkey Agar screening of stool specimens
Journal of Clinical Microbiology, 2004Co-Authors: Eileen J Klein, Jennifer R Stapp, Marguerite A Neill, John M Besser, Michael T Osterholm, Phillip I Tarr, Richard B Thomson, Patrick J Gavin, Lance R PetersonAbstract:The interesting paper by Gavin et al., describing their experience using an enzyme immunoassay (EIA) to identify stools containing Shiga toxin (Stx)-producing Escherichia coli (STEC) (3), adds to the growing literature that non-O157:H7 STEC are overlooked pathogens. However, as physicians, clinical and public health microbiologists, and disease control epidemiologists, we are concerned by the authors' use of an EIA to screen stools and, only if this test is positive, to then seek E. coli O157:H7 with sorbitol MacConkey Agar culture (SMAC).
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comparison of escherichia coli o157 h7 antigen detection in stool and broth cultures to that in sorbitol macconkey Agar stool cultures
Journal of Clinical Microbiology, 2000Co-Authors: Jennifer R Stapp, Eileen J Klein, Srdjan Jelacic, Yoolee Yea, Marc Fischer, Carla R Clausen, Xuan Qin, David L Swerdlow, Phillip I TarrAbstract:We evaluated the Meridian IC-STAT direct fecal and broth culture antigen detection methods with samples from children infected with Escherichia coli O157:H7 and correlated the antigen detection results with the culture results. Stools of 16 children who had recently had stool cultures positive for this pathogen (population A) and 102 children with diarrhea of unknown cause (population B) were tested with the IC-STAT device (direct testing). Fecal broth cultures were also tested with this device (broth testing). The results were correlated to a standard of the combined yield from direct culture of stools on Sorbitol-MacConkey (SMAC) Agar and culture of broth on SMAC Agar. Eleven (69%) of the population A stool specimens yielded E. coli O157:H7 when plated directly on SMAC Agar. Two more specimens yielded this pathogen when the broth culture was similarly plated. Of these 13 stool specimens, 8 and 13 were positive by direct and broth testing (respective sensitivities, 62 and 100%). Compared to the sensitivity of a simultaneously performed SMAC Agar culture, the sensitivity of direct testing was 73%. Three (3%) of the population B stool specimens contained E. coli O157:H7 on SMAC Agar culture; one and three of these stool specimens were positive by direct and broth testing, respectively. The direct and broth IC-STAT tests were 100% specific with samples from children from population B. Direct IC-STAT testing of stools is rapid, easily performed, and specific but is insufficiently sensitive to exclude the possibility of infection with E. coli O157:H7. Performing the IC-STAT test with a broth culture increases its sensitivity. However, attempts to recover E. coli O157:H7 by culture should not be abandoned but, rather, should be increased when the IC-STAT test result is positive.
Jennifer R Stapp - One of the best experts on this subject based on the ideXlab platform.
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real time pcr assay for detection and differentiation of shiga toxin producing escherichia coli from clinical samples
Journal of Clinical Microbiology, 2015Co-Authors: Eileen J Klein, Jennifer R Stapp, Xuan Qin, Emmanouil Galanakis, Anita Thomas, Shannon Rich, Anne Marie Buccat, Phillip I TarrAbstract:Timely accurate diagnosis of Shiga toxin-producing Escherichia coli (STEC) infections is important. We evaluated a laboratory-developed real-time PCR (LD-PCR) assay targeting stx1, stx2, and rfbEO157 with 2,386 qualifying stool samples submitted to the microbiology laboratory of a tertiary care pediatric center between July 2011 and December 2013. Broth cultures of PCR-positive samples were tested for Shiga toxins by enzyme immunoassay (EIA) (ImmunoCard STAT! enterohemorrhagic E. coli [EHEC]; Meridian Bioscience) and cultured in attempts to recover both O157 and non-O157 STEC. E. coli O157 and non-O157 STEC were detected in 35 and 18 cases, respectively. Hemolytic uremic syndrome (HUS) occurred in 12 patients (10 infected with STEC O157, one infected with STEC O125ac, and one with PCR evidence of STEC but no resulting isolate). Among the 59 PCR-positive STEC specimens from 53 patients, only 29 (54.7%) of the associated specimens were toxin positive by EIA. LD-PCR differentiated STEC O157 from non-O157 using rfbEO157, and LD-PCR results prompted successful recovery of E. coli O157 (n = 25) and non-O157 STEC (n = 8) isolates, although the primary cultures and toxin assays were frequently negative. A rapid "mega"-multiplex PCR (FilmArray gastrointestinal panel; BioFire Diagnostics) was used retrospectively, and results correlated with LD-PCR findings in 25 (89%) of the 28 Sorbitol-MacConkey Agar culture-negative STEC cases. These findings demonstrate that PCR is more sensitive than EIA and/or culture and distinguishes between O157 and non-O157 STEC in clinical samples and that E. coli O157:H7 remains the predominant cause of HUS in our institution. PCR is highly recommended for rapid diagnosis of pediatric STEC infections.
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shiga toxin antigen detection should not replace sorbitol macconkey Agar screening of stool specimens
Journal of Clinical Microbiology, 2004Co-Authors: Eileen J Klein, Jennifer R Stapp, Marguerite A Neill, John M Besser, Michael T Osterholm, Phillip I Tarr, Richard B Thomson, Patrick J Gavin, Lance R PetersonAbstract:The interesting paper by Gavin et al., describing their experience using an enzyme immunoassay (EIA) to identify stools containing Shiga toxin (Stx)-producing Escherichia coli (STEC) (3), adds to the growing literature that non-O157:H7 STEC are overlooked pathogens. However, as physicians, clinical and public health microbiologists, and disease control epidemiologists, we are concerned by the authors' use of an EIA to screen stools and, only if this test is positive, to then seek E. coli O157:H7 with sorbitol MacConkey Agar culture (SMAC).
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comparison of escherichia coli o157 h7 antigen detection in stool and broth cultures to that in sorbitol macconkey Agar stool cultures
Journal of Clinical Microbiology, 2000Co-Authors: Jennifer R Stapp, Eileen J Klein, Srdjan Jelacic, Yoolee Yea, Marc Fischer, Carla R Clausen, Xuan Qin, David L Swerdlow, Phillip I TarrAbstract:We evaluated the Meridian IC-STAT direct fecal and broth culture antigen detection methods with samples from children infected with Escherichia coli O157:H7 and correlated the antigen detection results with the culture results. Stools of 16 children who had recently had stool cultures positive for this pathogen (population A) and 102 children with diarrhea of unknown cause (population B) were tested with the IC-STAT device (direct testing). Fecal broth cultures were also tested with this device (broth testing). The results were correlated to a standard of the combined yield from direct culture of stools on Sorbitol-MacConkey (SMAC) Agar and culture of broth on SMAC Agar. Eleven (69%) of the population A stool specimens yielded E. coli O157:H7 when plated directly on SMAC Agar. Two more specimens yielded this pathogen when the broth culture was similarly plated. Of these 13 stool specimens, 8 and 13 were positive by direct and broth testing (respective sensitivities, 62 and 100%). Compared to the sensitivity of a simultaneously performed SMAC Agar culture, the sensitivity of direct testing was 73%. Three (3%) of the population B stool specimens contained E. coli O157:H7 on SMAC Agar culture; one and three of these stool specimens were positive by direct and broth testing, respectively. The direct and broth IC-STAT tests were 100% specific with samples from children from population B. Direct IC-STAT testing of stools is rapid, easily performed, and specific but is insufficiently sensitive to exclude the possibility of infection with E. coli O157:H7. Performing the IC-STAT test with a broth culture increases its sensitivity. However, attempts to recover E. coli O157:H7 by culture should not be abandoned but, rather, should be increased when the IC-STAT test result is positive.