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Rivas L, Duncan D, Wang J, Miller H, Wright J. Using CHROMagar™ STEC medium exclusively does not recover all clinically relevant Shiga toxin-producing Escherichia coli in Aotearoa, New Zealand. Lett Appl Microbiol 2024; 77:ovae033. [PMID: 38569656 DOI: 10.1093/lambio/ovae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/28/2024] [Accepted: 04/02/2024] [Indexed: 04/05/2024]
Abstract
Diagnostic laboratories in Aotearoa, New Zealand (NZ) refer cultures from faecal samples positive for Shiga toxin genes to the national Enteric Reference Laboratory for isolation of Shiga toxin-producing Escherichia coli (STEC) for epidemiological typing. As there was variation in the culture media being referred, a panel of 75 clinical isolates of STEC, representing 28 different serotypes, was used to assess six commercially available media and provide guidance to clinical laboratories. Recommendations were subsequently tested for a 3-month period, where STEC isolations and confirmations were assessed by whole genome sequencing analysis against the culture media referred. CHROMagar™ STEC (CH-STEC; CHROMagar Microbiology, Paris, France) or CH-STEC plus cefixime-tellurite sorbitol MacConkey agar was confirmed inferior to CH-STEC plus blood agar with vancomycin, cefsulodin, and cefixime (BVCC). The former resulted in fewer STEC types (n = 18) being confirmed compared to those from a combination of CH-STEC and BVCC (n = 42). A significant (P < .05) association with an STEC's ability to grow on CH-STEC and the presence of the ter gene cluster, and eae was observed. Culturing screen positive STEC samples onto both CH-STEC and BVCC ensures a consistently higher recovery of STEC from all clinical samples in NZ than CH-STEC alone.
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Affiliation(s)
- Lucia Rivas
- Institute of Environmental Science and Research (ESR), Christchurch Science Centre, 27 Creyke Road, Ilam, Christchurch 8041, New Zealand
| | - David Duncan
- Institute of Environmental Science and Research (ESR), Wallaceville Science Centre, 66 Ward Street, Wallaceville, Upper Hutt 5018, New Zealand
| | - Jing Wang
- Institute of Environmental Science and Research (ESR), Kenepuru Science Centre, 34 Kenepuru Drive, Kenepuru, Porirua 5022, New Zealand
| | - Hilary Miller
- Institute of Environmental Science and Research (ESR), Kenepuru Science Centre, 34 Kenepuru Drive, Kenepuru, Porirua 5022, New Zealand
| | - Jackie Wright
- Institute of Environmental Science and Research (ESR), Christchurch Science Centre, 27 Creyke Road, Ilam, Christchurch 8041, New Zealand
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Lewis GL, Cernicchiaro N, Moxley RA. Effect of potassium tellurite concentration in a chromogenic agar medium on isolation of tellurite-resistant "Top Seven" Shiga toxin-producing Escherichia coli from ground beef. J Food Prot 2023; 86:100017. [PMID: 36916584 DOI: 10.1016/j.jfp.2022.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 12/23/2022]
Abstract
The effect of potassium tellurite concentration in a chromogenic agar medium on the detection of tellurite-resistant "top seven" Shiga toxin-producing Escherichia coli (STEC) in beef was evaluated. Samples of ground beef were inoculated with tellurite-resistant STEC O26, O45, O103, O111, O121, O145, or O157 strains at geometric mean (±standard error of the mean) levels of 0, 49 (±1), 490 (±1), or 4900 (±1) CFU/10 g and enriched 1:10 (90 mL) in EC broth (40°C for 6 h). Following enrichment, aliquots of broth culture were treated by immunomagnetic separation with one of three pools of beads against STEC serogroups; pool I: O26, O45, and O121; pool II: O103, O111, and O145; and pool III: O157. After immunomagnetic separation, 50 μL of washed bead suspensions in buffered peptone water was spiral plated onto a modified Possé medium containing 0.5, 1.0, or 1.5 mg/L potassium tellurite, and incubated at 37°C for 18 h. Up to four isolated colonies were picked from each spiral plate based on expected colony phenotypes for STEC, and isolate identity was confirmed with an 11-plex PCR assay targeting the O serogroups and virulence genes. Overall, across all inoculum levels and strains, modified Possé media containing 0.5, 1.0, or 1.5 mg/L potassium tellurite each had a positive predictive value of 100%, and medium containing 0.5 mg/L potassium tellurite had numerically the highest sensitivity (100%) and negative predictive value (100%), which was significantly different from 1.5 mg/L (92.9% and 40.0%, respectively; P < 0.05). Similarly, there was an inverse relationship between potassium tellurite concentration and analytical specificity (number of colonies tested that were STEC-positive): 0.5 (1463 of 1482; 98.7%), 1.0 (1356 of 1411; 96.1%), and 1.5 mg/L (1187 of 1278; 92.9%; P < 0.05). These results suggest that 0.5 mg/L gives better performance than 1.0 or 1.5 mg/L of potassium tellurite in Possé medium for isolation of tellurite-resistant "top seven" STEC from ground beef.
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Affiliation(s)
- Gentry L Lewis
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Natalia Cernicchiaro
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Rodney A Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
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Prihandana GS, Sriani T, Muthi’ah AD, Machmudah A, Mahardika M, Miki N. Study Effect of nAg Particle Size on the Properties and Antibacterial Characteristics of Polysulfone Membranes. NANOMATERIALS 2022; 12:nano12030388. [PMID: 35159732 PMCID: PMC8840566 DOI: 10.3390/nano12030388] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 12/12/2022]
Abstract
Polysulfone ultrafiltration membranes were fabricated using various sizes (20, 40, and 90-210 nm) of silver nanoparticles (nAg) blended in a dope solution. To characterize the performance and properties of the prepared membranes, scanning electron microscopy (SEM), water contact angle, protein separation, water flux, and antibacterial tests were conducted. The characterization results revealed that when nAg particles (20 nm) were blended into the base polymer PSF, the PSF/nAg blended membrane had the lowest contact angle (58.5°) and surface energy (110.7 mN/m). When experimenting with ultrafiltration using protein solutions, bare PSF and PSF/nAg-20 blended membranes gave similar values of protein rejection: 93% of bovine serum albumin (BSA) and 70% of lysozyme rejection. Furthermore, SEM studies showed that the surface pore size was reduced by adding 20 nm nAg particles in the casting solution. Most importantly, the introduction of 40 nm nAg particles reduced the growth of bacterial colonies on the membrane surface by up to 72%. These findings revealed that nAg particles are expected to be a potential modifier for the fabrication of an ultrafiltration membrane.
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Affiliation(s)
- Gunawan Setia Prihandana
- Department of Industrial Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Jl. Dr. Ir. H. Soekarno, Surabaya 60115, Indonesia; (A.D.M.); (A.M.)
- Correspondence: ; Tel.: +62-881-0360-00830
| | - Tutik Sriani
- Department of Research and Development, PT. Global Meditek Utama, Sardonoharjo, Ngaglik, Sleman, Yogyakarta 55581, Indonesia;
| | - Aisyah Dewi Muthi’ah
- Department of Industrial Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Jl. Dr. Ir. H. Soekarno, Surabaya 60115, Indonesia; (A.D.M.); (A.M.)
| | - Affiani Machmudah
- Department of Industrial Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Jl. Dr. Ir. H. Soekarno, Surabaya 60115, Indonesia; (A.D.M.); (A.M.)
| | - Muslim Mahardika
- Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jalan Grafika No. 2, Yogyakarta 55281, Indonesia;
| | - Norihisa Miki
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan;
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Hu Y, Cui G, Fan Y, Liu Y, Zhou W, Huo S, Wu X, Song S, Cui X, Zhao L, Bai L, Cui S, He Z. Isolation and Characterization of Shiga Toxin-Producing Escherichia coli from Retail Beef Samples from Eight Provinces in China. Foodborne Pathog Dis 2021; 18:616-625. [PMID: 34403269 DOI: 10.1089/fpd.2021.0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
While Shiga toxin-producing Escherichia coli (STEC) is a major foodborne pathogen worldwide, data on the molecular and phylogenetic properties of STEC isolates from retail beef samples in China remain scant. Fresh retail beef samples (n = 1062) were collected from eight provinces, and STEC isolates were recovered and characterized. PCR data showed that more than 50% of the samples were stx positive, and 82 STEC isolates were recovered from 14.8% (79/535) stx-positive enriched broths. In contrast, all ciprofloxacin resistant isolates (n = 19) and 13 cefotaxime (CTX) resistant isolates were eae positive and belonged to three serotypes: O111:H8, O26:H11, or O157:H7. Point mutations in quinolone resistance-determining regions and plasmid-mediated quinolone resistance determinants were identified in 16 and 20 isolates, respectively. BlaCTX-M and a point mutation (C-42T) in ampC promoter were detected in 15 and 8 of the CTX resistant isolates, respectively. In addition, macrolide resistance gene mphA was identified in eight azithromycin resistant O111:H8 isolates and one O26:H11 isolate. Single nucleotide polymorphism analysis demonstrated that the O26 and O157 isolates had multiple origins, but the O111 isolates were closely related. Taken together, our data demonstrated that several sequence types associated with hemolytic uremic syndrome from the retail beef samples in China had developed into dangerous multidrug resistant pathogens. The resistant phenotype can facilitate their transmission among the farm animals and human beings when there is an antimicrobial selective pressure.
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Affiliation(s)
- Ying Hu
- Department of Food Science, College of Food Science, Southwest University, Chongqing, China
| | - Guangqing Cui
- Department of Microbiology, Shanxi Provincial Institute for Food and Drug Control, Taiyuan, China
| | - Yiling Fan
- Department of Microbiology, NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology, Shanghai Institute for Food and Drug Control, Shanghai, China
| | - Yan Liu
- Department of Microbiology, Hubei Provincial Institute for Food Supervision and Test, Wuhan, China
| | - Wei Zhou
- Department of Microbiology, Hebei Food Inspection and Research Institute, Hebei Food Safety Key Laboratory, Zhengzhou, China
| | - Shengnan Huo
- Department of Microbiology, Shandong Institute for Food and Drug Control, Jinan, China
| | - Xin Wu
- Department of Microbiology, Jiang Xi Institute for Food Control, Nanchang, China
| | - Sheng Song
- Department of Microbiology, Hunan Provincial Key Laboratory of Food Safety Monitoring and Early Warning, Hunan Institute of Food Quality Supervision Inspection and Research, Changsha, China
| | - Xuewen Cui
- Department of Microbiology, Microbiological Inspection Center, Sichuan Institute for Food and Drug Control, Chengdu, China
| | - Linna Zhao
- Department of Food Science, The National Institutes for Food and Drug Control, Beijing, China
| | - Li Bai
- Department of Microbiology, Key Laboratory of Food Safety Risk Assessment, National Health Commission of the People's Republic of China, China National Center for Food Safety Risk Assessment, Beijing, China
| | - Shenghui Cui
- Department of Food Science, The National Institutes for Food and Drug Control, Beijing, China
| | - Zhifei He
- Department of Food Science, College of Food Science, Southwest University, Chongqing, China.,Department of Microbiology, Chongqing Engineering Research Center of Regional Food, Chongqing, China
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Lewis GL, Cernicchiaro N, Moxley RA. Performance of Chromogenic Agar Media for Isolation of Shiga Toxin-Producing Escherichia coli from Ground Beef. J Food Prot 2020; 83:1149-1154. [PMID: 32572495 DOI: 10.4315/jfp-19-585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/09/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT The performance of three chromogenic agar media for detection of the "top seven" Shiga toxin-producing Escherichia coli (STEC) in beef was compared. Samples of retail ground beef were inoculated with STEC O26, O45, O103, O111, O121, O145, or O157 at geometric mean (±standard error of the mean) levels of 0, 48 (±1), 420 (±1), 4,100 (±1), or 45,000 (±1) CFU/10 g and enriched 1:10 (90 mL) in EC broth (40°C for 6 h). Following enrichment, aliquots of broth culture were treated by immunomagnetic separation with one of three pools of beads against the seven STEC serogroups: pool I, O26, O45, and O121; pool II, O103, O111, and O145; and pool III, O157. After immunomagnetic separation, 50 μL of washed bead suspensions in buffered peptone water were spiral plated onto modified Rainbow Agar O157 (mRBA), CHROMagar STEC (CS), or modified Possé differential medium (mPossé2) and incubated at 37°C for 18 h. Up to six isolated colonies were picked from each spiral plate based on expected colony phenotypes for STEC on the respective media, and isolate identity was confirmed with an 11-plex PCR assay targeting the O serogroups and virulence genes. Overall, mRBA had the highest sensitivity (99.2%), correctly detecting a significantly higher proportion of STEC serogroups than either CS (79.4%; P < 0.05) or mPossé2 (91.7%; P < 0.05). mRBA also had the highest negative predictive value (90.0%), correctly identifying a significantly higher proportion of true-negative samples compared with CS (25.7%; P < 0.05) and mPossé2 (46.2%; P < 0.05). However, mRBA also had the lowest analytical specificity of 83.2% (P < 0.05), yielding the lowest proportion of colonies tested that were STEC positive (3,548 of 4,263) compared with 97.7% (3,607 of 3,693) for mPossé2 and 98.0% (2,875 of 2,935) for CS. Reduced specificity results in more work and higher expense due to the increased number of colonies that must be tested. Further improvements in agar culture media for non-O157 STEC isolation are needed. HIGHLIGHTS
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Affiliation(s)
- Gentry L Lewis
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0905 (ORCID: https://orcid.org/0000-0002-5377-7716 [R.A.M.])
| | - Natalia Cernicchiaro
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506 (ORCID: https://orcid.org/0000-0001-8649-6470 [N.C.])
| | - Rodney A Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0905 (ORCID: https://orcid.org/0000-0002-5377-7716 [R.A.M.])
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Using hydrochloric acid and bile resistance for optimized detection and isolation of Shiga toxin-producing Escherichia coli (STEC) from sprouts. Int J Food Microbiol 2020; 322:108562. [PMID: 32109682 DOI: 10.1016/j.ijfoodmicro.2020.108562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 11/21/2022]
Abstract
Shiga toxin-producing Escherichia coli (STEC) in sprouts have caused large scale outbreaks in the past involving severe illness. The combination of this very diverse pathogen and a food matrix with high numbers of background microbiota poses a particular challenge for detection and isolation. An acid treatment of the enrichment before plating on agar has been shown to improve the recovery of STEC from sprouts. After enrichment in buffered peptone water (BPW) at 37 °C we applied an acid treatment, followed by plating on tryptone bile x-glucuronide (TBX) agar (acid bile method). An inter-laboratory study was organized with 21 laboratories taking part to evaluate the performance parameters and applicability of the acid bile method. A sample set of six sprout samples was prepared consisting of two uninoculated samples and four spiked samples, each containing one of two STEC strains at one of two concentrations (low and high). Analyzing a set of six samples at the National Reference Laboratory (NRL E. coli), we determined the relative abundance of STEC without, after acid-, after bile- and after acid-bile treatment using real-time PCR. The participating laboratories successfully applied the acid bile method and were better able to detect (sensitivity 92.9% vs. 70.0%) and isolate (sensitivity 87.5% vs. 31.3%) STEC from positive samples using the acid bile method compared to non-acid methods. The relative limit of detection (RLOD) after isolation using the acid bile method (vs. non-acid method) was <1 for both STEC strains used, BfR-EC-14434 O133:H25 (0.146) and BfR-EC-16015 O26:H11 (0.073). A collection of STEC (n = 71) of diverse type and characteristics was assessed for their resistance towards the acid bile treatment selection. The majority (n = 65) of STEC strains could be recovered after acid treatment on TBX plates. However, a few strains (n = 6), among them clinical isolates were (partly) sensitive. These results suggest that an acid bile method is a rapid and reasonable approach to improve the recovery of STEC from sprouts when used in combination with methods targeting other selection markers.
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Dong P, Xiao T, Nychas GJE, Zhang Y, Zhu L, Luo X. Occurrence and characterization of Shiga toxin-producing Escherichia coli (STEC) isolated from Chinese beef processing plants. Meat Sci 2020; 168:108188. [PMID: 32470758 DOI: 10.1016/j.meatsci.2020.108188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/09/2020] [Accepted: 05/10/2020] [Indexed: 11/26/2022]
Abstract
In order to investigate the prevalence, O serogroup, virulence genes and antibiotic resistance of Shiga toxin-producing Escherichia coli (STEC) in two beef plants in China, a total of 600 samples collected from 6 sites (feces, hide, pre-evisceration carcasses, post-washing carcasses, chilled carcasses and meat, 50 samples per site in each plant) were screened for the existence of Shiga toxin-encoding genes by PCR. STEC strains in positives were isolated and characterized for serogroup and antibiotic sensitivity. The PCR prevalence rate in each site was 45.0%, 31.0%, 14.0%, 13.0%, 9.0% and 18.0%, respectively. Sixteen O serogroups including O157, O146 and O76 which are associated with disease were identified. The existence of both stx1 and stx2 genes was the most common among the isolated strains (42.3%). Among the overall 26 isolates, seven and three were resistant to at least three and ten antibiotics, indicating a high antibiotic resistance in STEC strains isolated from the study.
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Affiliation(s)
- Pengcheng Dong
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Tongtong Xiao
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - George-John E Nychas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food and Nutritional Sciences, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Yimin Zhang
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Lixian Zhu
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
| | - Xin Luo
- Lab of Beef Processing and Quality Control, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
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McAuliffe GN, Tse F, Qiao H, Moore S, Bissessor L, Thompson B, McLaughlin V, Upton A, Taylor SL. Isolate independent molecular typing improves the yield of O typing of infections due to Shiga toxin producing Escherichia coli. Pathology 2020; 52:460-465. [PMID: 32317174 DOI: 10.1016/j.pathol.2020.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/05/2020] [Accepted: 02/21/2020] [Indexed: 11/19/2022]
Abstract
Molecular screening has increased detection of Shiga-toxin producing Escherichia coli (STEC). However, it is difficult to isolate the organism for epidemiological typing. We applied a molecular method for direct detection of nine O types from 110 stx positive faeces samples and compared the results with conventional isolate based methods. Using conventional methods 55/110 (50%) samples were O typed. Using the molecular method, 72/110 (65%) were O typed, including 23/38 (61%) culture negative samples. Combining both techniques typed 88/110 (80%) of samples. Molecular typing increased detection of O128 (2-25%, p<0.001), O26 (11-16%) O45 (0-6%) and O103 (1-6%) infections. Molecular typing of STEC direct from faecal samples improved O type yield; risk of bias in epidemiological and surveillance activities may be reduced by inclusion of culture independent typing methods.
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Affiliation(s)
| | - Fifi Tse
- Department of Microbiology, Middlemore Hospital, Auckland, New Zealand
| | - Helen Qiao
- Department of Microbiology, Middlemore Hospital, Auckland, New Zealand
| | - Sharon Moore
- Department of Microbiology, Labtests, Auckland, New Zealand
| | | | - Bryn Thompson
- Auckland Regional Public Health Service, Auckland, New Zealand
| | | | - Arlo Upton
- Department of Microbiology, Labtests, Auckland, New Zealand
| | - Susan L Taylor
- Department of Microbiology, Middlemore Hospital, Auckland, New Zealand
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Montso PK, Mlambo V, Ateba CN. The First Isolation and Molecular Characterization of Shiga Toxin-Producing Virulent Multi-Drug Resistant Atypical Enteropathogenic Escherichia coli O177 Serogroup From South African Cattle. Front Cell Infect Microbiol 2019; 9:333. [PMID: 31608246 PMCID: PMC6769085 DOI: 10.3389/fcimb.2019.00333] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/10/2019] [Indexed: 12/15/2022] Open
Abstract
Atypical enteropathogenic E. coli (aEPEC) is a group of diarrhoeagenic Escherichia coli with high diversity of serogroups, which lack the bundle-forming pili (BFP) and genes encoding for shiga toxins. The aim of this study was to isolate, identify and determine virulence and antibiotic resistance profiles of aEPEC O177 strains from cattle feces. A total of 780 samples were collected from beef and dairy cattle and analyzed for the presence of E. coli O177. One thousand two hundred and seventy-two (1272) presumptive isolates were obtained and 915 were confirmed as E. coli species. Three hundred and seventy-six isolates were positively confirmed as E. coli O177 through amplification of rmlB and wzy gene sequences using multiplex PCR. None of these isolates harbored bfpA gene. A larger proportion (12.74%) of the isolates harbored hlyA gene while 11.20, 9.07, 7.25, 2.60, and 0.63% possessed stx2, stx1, eaeA, stx2a, and stx2d, respectively. Most of E. coli O177 isolates carried stx2/hlyA (9.74%). Furthermore, 7.40% of the isolates harbored stx1/stx2 while 7.09% possessed stx1/stx2/hlyA genes. Only one isolate harbored stx1/stx2/hly/eaeA/stx2a/stx2d while 5.11% of the isolates harbored all the four major virulence genes stx1/stx2/hlyA/eaeA, simultaneously. Further analysis revealed that the isolates displayed varied antimicrobial resistance to erythromycin (63.84%), ampicillin (21.54%), tetracycline (13.37%), streptomycin (17.01%), kanamycin (2.42%), chloramphenicol (1.97%), and norfloxacin (1.40%). Moreover, 20.7% of the isolates exhibited different phenotypic multi-drug resistance patterns. All 73 isolates harbored at least one antimicrobial resistance gene. The aadA, streA, streB, erm, and tetA resistance genes were detected separately and/or concurrently. In conclusion, our findings indicate that environmental isolates of aEPEC O177 strains obtained from cattle in South Africa harbored virulence and antimicrobial resistance gene determinants similar to those reported in other shiga-toxin producing E. coli strains and suggest that these determinants may contribute to the virulence of the isolates.
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Affiliation(s)
- Peter Kotsoana Montso
- Bacteriophage Therapy and Phage Bio-control Laboratory, Department of Microbiology, Faculty of Natural and Agricultural Sciences, North-West University, Mmabatho, South Africa
| | - Victor Mlambo
- Faculty of Agriculture and Natural Sciences School of Agricultural Sciences, University of Mpumalanga, Nelspruit, South Africa
| | - Collins Njie Ateba
- Bacteriophage Therapy and Phage Bio-control Laboratory, Department of Microbiology, Faculty of Natural and Agricultural Sciences, North-West University, Mmabatho, South Africa
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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Kalule JB, Keddy KH, Nicol MP. Characterisation of STEC and other diarrheic E. coli isolated on CHROMagar™STEC at a tertiary referral hospital, Cape Town. BMC Microbiol 2018; 18:55. [PMID: 29884127 PMCID: PMC5994027 DOI: 10.1186/s12866-018-1195-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/23/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Shiga toxin producing E. coli (STEC) is an emerging zoonotic pathogen that can cause acute renal failure, especially in children. Clinical microbiology laboratories may fail to detect STEC and other diarrhoeic E. coli unless purposive rigorous screening procedures are followed using appropriate diagnostic technology; CHROMagar™STEC has rarely been used for isolation of African diarrhoeic E. coli hence characteristics of isolates on this medium are not yet fully understood. This study aimed to determine the prevalence and characteristics of STEC and other diarrhoeic E. coli isolated on CHROMagar™STEC from stool samples submitted to the microbiology laboratory of a South African public sector tertiary care hospital. RESULTS In total, 733 stool samples were tested. Of these, 4.5% (33/733) possessed diarrhoeic E. coli. Of the diarrheic E. coli, 5/33 (15.2%) were STEC, 15/33 (45.5%) EAggEC, 6/33 (18.2%) atypical EPEC, 5/33 (15.2%) typical EPEC, and 1/33 (3%) DAEC. None of the STEC isolates had been identified by routine testing (based on using sorbitol media to test for E. coli O157: H7 strains and not the other STEC) in the laboratory. Of the 33 strains, 55% (95% CI = 40.8-72.7) showed resistance to ampicillin. CONCLUSIONS CHROMagar™STEC enabled detection of tellurite - resistant diarrhoeic E. coli that would be missed using routine methods. Further studies are needed to determine the proportion and characteristics of those which might have been missed using this approach.
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Affiliation(s)
- John Bosco Kalule
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
| | - Karen H. Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mark P. Nicol
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
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12
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Kase JA, Maounounen-Laasri A, Lin A. Rapid Identification of Shiga Toxin-Producing Escherichia coli O Serogroups from Fresh Produce and Raw Milk Enrichment Cultures by Luminex Bead-Based Suspension Array. J Food Prot 2016; 79:1623-1629. [PMID: 28221928 DOI: 10.4315/0362-028x.jfp-16-070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) Chapter 4a describes a Luminex microbead-based suspension array used to screen colonies for 11 clinically relevant Shiga toxin-producing Escherichia coli (STEC) serogroups: O26, O45, O91, O103, O104, O111, O113, O121, O128, O145, and O157. We evaluated the usefulness of this method to identify STEC-positive enrichment samples before agar plating. Twelve E. coli strains were added to three types of fresh produce (bagged baby spinach, alfalfa sprouts, and cilantro) at levels near the detection limit of the test. A subset of these strains (six O serogroups) was similarly evaluated in raw milk. For comparison, portions of each of the 168 enrichment cultures were analyzed for serogroup by a real-time PCR assay and a Bio-Plex 200 assay with the bead-based suspensions. No false-positive results were obtained. Of the 112 samples with a reported cycle threshold (CT) value, 101 undiluted, diluted, or extracted enrichment cultures also produced ratios above 5.0 in the Bio-Plex assay. When PCR CT values approached or were greater than 35, Bio-Plex detection became less reliable. Using undiluted or extracted enrichment cultures resulted in a significantly larger number of positive results. With the same enrichment material prepared for real-time PCR analysis as described in the BAM Chapter 4a, the STEC microbead-based suspension array can accurately screen food enrichment cultures.
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Affiliation(s)
- Julie A Kase
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland 20740
| | - Anna Maounounen-Laasri
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, Maryland 20740.,Oak Ridge Research Institute for Science and Education, Oak Ridge, Tennessee 37830
| | - Andrew Lin
- U.S. Food and Drug Administration, Office of Regulatory Affairs, San Francisco Laboratory, Alameda, California 94502, USA
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13
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Stromberg ZR, Lewis GL, Moxley RA. Comparison of Agar Media for Detection and Quantification of Shiga Toxin-Producing Escherichia coli in Cattle Feces. J Food Prot 2016; 79:939-49. [PMID: 27296597 DOI: 10.4315/0362-028x.jfp-15-552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The isolation and quantification of non-O157 Shiga toxin-producing Escherichia coli (STEC) from cattle feces are challenging. The primary objective of this study was to evaluate the performance of selected agar media in an attempt to identify an optimal medium for the detection and quantification of non-O157 STEC in cattle feces. Comparison studies were performed using CHROMagar STEC, Possé differential agar (Possé), Possé modified by the reduction or addition of antimicrobials, STEC heart infusion washed blood agar with mitomycin C (SHIBAM), and SHIBAM modified by the addition of antimicrobials. Fourteen STEC strains, two each belonging to serogroups O26, O45, O103, O111, O121, O145, and O157, were used to test detection in inoculated fecal suspensions at concentrations of 10(2) or 10(3) CFU/g. One STEC strain from each of these seven serogroups was used to estimate the concentration of recovered STEC in feces inoculated at 10(3), 10(4), or 10(5) CFU/g. Significantly more suspensions (P < 0.05) were positive for STEC when plated on Possé containing reduced concentrations of novobiocin and potassium tellurite compared with SHIBAM, but not SHIBAM modified by containing these same antimicrobials at the same concentrations. Numerically, more suspensions were positive for STEC by using this same form of modified Possé compared with Possé, but this difference was not statistically significant. More suspensions were positive for STEC cultured on CHROMagar STEC compared with those on Possé (P < 0.05) and on modified Possé (P = 0.05). Most inoculated fecal suspensions below 10(4) CFU/g of feces were underestimated or not quantifiable for the concentration of STEC by using CHROMagar STEC or modified Possé. These results suggest that CHROMagar STEC performs better than Possé or SHIBAM for detection of STEC in bovine feces, but adjustments in the concentrations of novobiocin and potassium tellurite in the latter two media result in significant improvements in their performance.
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Affiliation(s)
- Zachary R Stromberg
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA
| | - Gentry L Lewis
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA
| | - Rodney A Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA.
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14
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Kerangart S, Douëllou T, Delannoy S, Fach P, Beutin L, Sergentet-Thévenot D, Cournoyer B, Loukiadis E. Variable tellurite resistance profiles of clinically-relevant Shiga toxin-producing Escherichia coli (STEC) influence their recovery from foodstuffs. Food Microbiol 2016; 59:32-42. [PMID: 27375242 DOI: 10.1016/j.fm.2016.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/04/2016] [Accepted: 05/09/2016] [Indexed: 01/08/2023]
Abstract
Tellurite (Tel)-amended selective media and resistance (Tel-R) are widely used for detecting Shiga toxin-producing Escherichia coli (STEC) from foodstuffs. Tel-R of 81 O157 and non-O157 STEC strains isolated from animal, food and human was thus investigated. Variations of STEC tellurite minimal inhibitory concentration (MIC) values have been observed and suggest a multifactorial and variable tellurite resistome between strains. Some clinically-relevant STEC were found highly susceptible and could not be recovered using a tellurite-based detection scheme. The ter operon was highly prevalent among highly Tel-R STEC but was not always detected among intermediately-resistant strains. Many STEC serogroup strains were found to harbor sublines showing a gradient of MIC values. These Tel-R sublines showed statistically significant log negative correlations with increasing tellurite concentration. Whatever the tellurite concentration, the highest number of resistant sublines was observed for STEC belonging to the O26 serogroup. Variations in the number of these Tel-R sublines could explain the poor recovery of some STEC serogroups on tellurite-amended media especially from food products with low levels of contamination. Comparison of tellurite MIC values and distribution of virulence-related genes showed Tel-R and virulence to be related.
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Affiliation(s)
- Stéphane Kerangart
- University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France
| | - Thomas Douëllou
- University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; Institut National de Recherche Agronomique, Unité de Recherches Fromagères, 15000 Aurillac, France
| | - Sabine Delannoy
- Université Paris-Est, ANSES, Laboratoire de Sécurité des Aliments, Plateforme IdentyPath, 14 Rue Pierre et Marie Curie, 94701 Maisons-Alfort, France
| | - Patrick Fach
- Université Paris-Est, ANSES, Laboratoire de Sécurité des Aliments, Plateforme IdentyPath, 14 Rue Pierre et Marie Curie, 94701 Maisons-Alfort, France
| | - Lothar Beutin
- National Reference Laboratory for Escherichia coli (Including VTEC), Department of Biological Safety, Federal Institute for Risk Assessment (BfR), D-12277 Berlin, Germany
| | - Delphine Sergentet-Thévenot
- University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; University of Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for Escherichia coli (Including VTEC), Marcy L'Etoile, France
| | - Benoit Cournoyer
- University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France
| | - Estelle Loukiadis
- University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; University of Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for Escherichia coli (Including VTEC), Marcy L'Etoile, France.
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15
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Parsons BD, Zelyas N, Berenger BM, Chui L. Detection, Characterization, and Typing of Shiga Toxin-Producing Escherichia coli. Front Microbiol 2016; 7:478. [PMID: 27148176 PMCID: PMC4828450 DOI: 10.3389/fmicb.2016.00478] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 03/22/2016] [Indexed: 02/04/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are responsible for gastrointestinal diseases reported in numerous outbreaks around the world. Given the public health importance of STEC, effective detection, characterization and typing is critical to any medical laboratory system. While non-O157 serotypes account for the majority of STEC infections, frontline microbiology laboratories may only screen for STEC using O157-specific agar-based methods. As a result, non-O157 STEC infections are significantly under-reported. This review discusses recent advances on the detection, characterization and typing of STEC with emphasis on work performed at the Alberta Provincial Laboratory for Public Health (ProvLab). Candidates for the detection of all STEC serotypes include chromogenic agars, enzyme immunoassays (EIA) and quantitative real time polymerase chain reaction (qPCR). Culture methods allow further characterization of isolates, whereas qPCR provides the greatest sensitivity and specificity, followed by EIA. The virulence gene profiles using PCR arrays and stx gene subtypes can subsequently be determined. Different non-O157 serotypes exhibit markedly different virulence gene profiles and a greater prevalence of stx1 than stx2 subtypes compared to O157:H7 isolates. Finally, recent innovations in whole genome sequencing (WGS) have allowed it to emerge as a candidate for the characterization and typing of STEC in diagnostic surveillance isolates. Methods of whole genome analysis such as single nucleotide polymorphisms and k-mer analysis are concordant with epidemiological data and standard typing methods, such as pulsed-field gel electrophoresis and multiple-locus variable number tandem repeat analysis while offering additional strain differentiation. Together these findings highlight improved strategies for STEC detection using currently available systems and the development of novel approaches for future surveillance.
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Affiliation(s)
- Brendon D. Parsons
- Laboratory Medicine and Pathology, University of AlbertaEdmonton, AB, Canada
| | - Nathan Zelyas
- Medical Microbiology and Immunology, University of AlbertaEdmonton, AB, Canada
| | - Byron M. Berenger
- Medical Microbiology and Immunology, University of AlbertaEdmonton, AB, Canada
| | - Linda Chui
- Laboratory Medicine and Pathology, University of AlbertaEdmonton, AB, Canada
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16
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Verhaegen B, Van Damme I, Heyndrickx M, Botteldoorn N, Elhadidy M, Verstraete K, Dierick K, Denayer S, De Zutter L, De Reu K. Evaluation of detection methods for non-O157 Shiga toxin-producing Escherichia coli from food. Int J Food Microbiol 2016; 219:64-70. [PMID: 26736066 DOI: 10.1016/j.ijfoodmicro.2015.12.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
Abstract
Shiga toxin-producing Escherichia coli (STEC) remains a major foodborne pathogen of concern across the globe. Rapid detection and isolation of this pathogen is of great importance for public health reasons. In this study the detection and isolation of four non-O157 STEC strains (O26, O103, O111, O145) from different artificially contaminated matrices, namely ground (minced) beef, cattle carcass swab, lettuce mix and sprouted soy beans, were evaluated. Low amounts of STEC were used (0.25-1.40 cfu/g) to spike the samples. All samples were enriched in parallel in Buffered Peptone Water (BPW) and Brila broth. After enrichment, detection was performed using real-time PCR (qPCR), and isolation using two chromogenic agar media, CHROMagar™ STEC and ChromID™ EHEC. Inoculation on the agar media was performed either directly after enrichment or after the use of an acid treatment procedure. Furthermore, the use of this procedure was also tested on naturally contaminated food products, using 150 stx-positive samples. Although the qPCR Cycle Threshold (Ct) values were lower after enrichment in Brila broth, no significant differences in recovery were observed between both enrichment broths. Both agar media were equally suitable for the isolation of STEC, although a significantly higher recovery was obtained when using both agar media in parallel. For samples with a Ct value above 25, an acid treatment step prior to isolation ensured a significant improvement in the recovery of STEC due to the reduction in background microbiota. This acid treatment procedure proved especially useful for the isolation of STEC from sprouted soy bean samples.
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Affiliation(s)
- Bavo Verhaegen
- Institute for Agriculture and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium; Ghent University, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Inge Van Damme
- Ghent University, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Marc Heyndrickx
- Institute for Agriculture and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium; Ghent University, Faculty of Veterinary Medicine, Department of Pathology, Bacteriology and Poultry Diseases, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Nadine Botteldoorn
- Foodborne Pathogens, Scientific Institute of Public Health, Juliettte Wytsmanstraat 14, 1050 Brussels, Belgium
| | - Mohamed Elhadidy
- Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Karen Verstraete
- Institute for Agriculture and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium
| | - Katelijne Dierick
- Foodborne Pathogens, Scientific Institute of Public Health, Juliettte Wytsmanstraat 14, 1050 Brussels, Belgium
| | - Sarah Denayer
- Foodborne Pathogens, Scientific Institute of Public Health, Juliettte Wytsmanstraat 14, 1050 Brussels, Belgium
| | - Lieven De Zutter
- Ghent University, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Koen De Reu
- Institute for Agriculture and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
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17
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Brusa V, Piñeyro PE, Galli L, Linares LH, Ortega EE, Padola NL, Leotta GA. Isolation of Shiga Toxin-Producing Escherichia coli from Ground Beef Using Multiple Combinations of Enrichment Broths and Selective Agars. Foodborne Pathog Dis 2016; 13:163-70. [PMID: 26836701 DOI: 10.1089/fpd.2015.2034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens, and beef cattle are recognized as the principal reservoir. The aims of this study were (1) to identify the most sensitive combination of selective enrichment broths and agars for STEC isolation in artificially inoculated ground beef samples, and (2) to evaluate the most efficient combination(s) of methods for naturally contaminated ground beef samples. A total of 192 ground beef samples were artificially inoculated with STEC and non-stx bacterial strains. A combination of four enrichment broths and three agars were evaluated for sensitivity, specificity, and positive predictive value for STEC isolation from experimentally inoculated samples. Enrichments with either modified tryptic soy broth (mTSB) containing 8 mg/L novobiocin (mTSB-8) or modified Escherichia coli (mEC) broth followed by isolation in MacConkey agar were the most sensitive combinations for STEC isolation of artificially inoculated samples. Independently, both enrichments media followed by isolation in MacConkey were used to evaluate ground beef samples from 43 retail stores, yielding 65.1% and 58.1% stx-positive samples by RT-PCR, respectively. No difference was observed in the isolate proportions between these two methods (8/25 [32%] and 8/28 [28.6%]). Identical serotypes and stx genotypes were observed in STEC strains isolated from the same samples by either method. In this study, no single enrichment protocol was sufficient to detect all STEC in artificially inoculated samples and had considerable variation in detection ability with naturally contaminated samples. Moreover, none of the single or combinations of multiple isolation agars used were capable of identifying all STEC serogroups in either artificially inoculated or naturally occurring STEC-contaminated ground beef. Therefore, it may be prudent to conclude that there is no single method or combination of isolation methods capable of identifying all STEC serogroups.
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Affiliation(s)
- Victoria Brusa
- 1 Laboratorio de Microbiología de Alimentos, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata (UNLP) , Buenos Aires, Argentina .,3 Instituto de Genética Veterinaria "Ing. Fernando N. Dulout," Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) La Plata, Facultad de Ciencias Veterinarias UNLP , Buenos Aires, Argentina
| | - Pablo E Piñeyro
- 2 Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University , Ames, Iowa
| | - Lucía Galli
- 3 Instituto de Genética Veterinaria "Ing. Fernando N. Dulout," Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) La Plata, Facultad de Ciencias Veterinarias UNLP , Buenos Aires, Argentina
| | - Luciano H Linares
- 1 Laboratorio de Microbiología de Alimentos, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata (UNLP) , Buenos Aires, Argentina
| | - Emanuel E Ortega
- 1 Laboratorio de Microbiología de Alimentos, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata (UNLP) , Buenos Aires, Argentina
| | - Nora L Padola
- 4 Centro de Investigación Veterinaria Tandil, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICPBA), Facultad Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires , Buenos Aires, Argentina
| | - Gerardo A Leotta
- 3 Instituto de Genética Veterinaria "Ing. Fernando N. Dulout," Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) La Plata, Facultad de Ciencias Veterinarias UNLP , Buenos Aires, Argentina
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18
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Bae E, Kim H, Rajwa B, Thomas JG, Robinson JP. Current status and future prospects of using advanced computer-based methods to study bacterial colonial morphology. Expert Rev Anti Infect Ther 2015; 14:207-18. [PMID: 26582139 DOI: 10.1586/14787210.2016.1122524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite the advancement of recent molecular technologies, culturing is still considered the gold standard for microbial sample analysis. Here we review three different bacterial colony-based screening modalities that provide significant information beyond the simple shape and color of the colony. The plate imaging technique provides numeration and quantitative spectral reflectance information for each colony, while Raman spectroscopic analysis of bacteria colonies relates the Raman-shifted peaks to specific chemical bonding. Finally, the elastic-light-scatter technique provides a volumetric interaction of the whole colony through laser-bacteria interactions, instantly capturing the morphological traits of the colony and allowing quantitative classifications.
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Affiliation(s)
- Euiwon Bae
- a School of Mechanical Engineering , Purdue University , West Lafayette , IN , USA
| | - Huisung Kim
- a School of Mechanical Engineering , Purdue University , West Lafayette , IN , USA
| | - Bartek Rajwa
- b Bindley Bioscience Center , Purdue University , West Lafayette , IN , USA
| | - John G Thomas
- c Microbiology Laboratory, Department of Laboratory Medicine , Allegheny Health Network , Pittsburgh , PA , USA
| | - J Paul Robinson
- d School of Veterinary Medicine , Purdue University , West Lafayette , IN , USA.,e Weldon School of Biomedical Engineering , Purdue University , West Lafayette , IN , USA
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19
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Verhaegen B, De Reu K, Heyndrickx M, De Zutter L. Comparison of Six Chromogenic Agar Media for the Isolation of a Broad Variety of Non-O157 Shigatoxin-Producing Escherichia coli (STEC) Serogroups. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:6965-78. [PMID: 26090610 PMCID: PMC4483743 DOI: 10.3390/ijerph120606965] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/02/2015] [Accepted: 06/11/2015] [Indexed: 11/16/2022]
Abstract
The isolation of non-O157 STEC from food samples has proved to be challenging. The selection of a suitable selective isolation agar remains problematic. The purpose of this study was to qualitatively and quantitatively evaluate six chromogenic agar media for the isolation of STEC: Tryptone Bile X-glucuronide agar (TBX), Rainbow® Agar O157 (RB), Rapid E. coli O157:H7 (RE), Modified MacConkey Agar (mMac), CHROMagarTM STEC (Chr ST) and chromIDTM EHEC (Chr ID). During this study, 45 E. coli strains were used, including 39 STEC strains belonging to 16 different O serogroups and 6 non-STEC E. coli. All E. coli strains were able to grow on TBX and RB, whereas one STEC strain was unable to grow on Chr ID and a number of other STEC strains did not grow on mMac, CHROMagar STEC and Rapid E. coli O157:H7. However, only the latter three agars were selective enough to completely inhibit the growth of the non-STEC E. coli. Our conclusion was that paired use of a more selective agar such as CHROMagar STEC together with a less selective agar like TBX or Chr ID might be the best solution for isolating non-O157 STEC from food.
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Affiliation(s)
- Bavo Verhaegen
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
- Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - Koen De Reu
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
| | - Marc Heyndrickx
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
- Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - Lieven De Zutter
- Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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20
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Bai X, Wang H, Xin Y, Wei R, Tang X, Zhao A, Sun H, Zhang W, Wang Y, Xu Y, Zhang Z, Li Q, Xu J, Xiong Y. Prevalence and characteristics of Shiga toxin-producing Escherichia coli isolated from retail raw meats in China. Int J Food Microbiol 2015; 200:31-8. [DOI: 10.1016/j.ijfoodmicro.2015.01.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/31/2014] [Accepted: 01/24/2015] [Indexed: 12/19/2022]
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