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Yin C, Yang W, Lv Y, Zhao P, Wang J. Clonal spread of carbapenemase-producing Enterobacteriaceae in a region, China. BMC Microbiol 2022; 22:81. [PMID: 35350977 PMCID: PMC8962535 DOI: 10.1186/s12866-022-02497-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 03/14/2022] [Indexed: 11/24/2022] Open
Abstract
Background The increasing number of carbapenemase-producing Enterobacterales (CPE) has become a serious problem globally. This study aimed to elucidate their geographically epidemiological characteristics. Methods Resistance genes were identified by polymerase chain reaction (PCR) and sequencing. Bacterial genotyping was studied using multilocus sequence typing (MLST) and wzi typing. The transferability of carbapenemase genes was determined by a broth mating method. The relationships between the rates of antimicrobial consumption and the prevalence of CRE were performed by Pearson's or Spearman's correlation analyses. Results A total of 930 phenotypically confirmed carbapenem-resistant Enterobacterales (CRE) isolates collected from 19 hospitals were genotypically characterized. K. pneumoniae (KP) and E. coli isolates were 785 (85.14%) and 96 (10.41%) among 922 CPE isolates. Two major carbapenemase genes blaKPC-2 and blaNDM in CPE isolates accounted for 84.6% (n = 780) and 13.77% (n = 127). ST11 comprised 86.83% (633/729) of KPC-2 KP isolates. Different combinations of extended spectrum-β-lactamase (ESBL) genes of blaSHV, blaCTX, and blaTEM were found in KPC-2 producing KP isolates, and blaCTM-M-14/15, blaSHV-11/12 and blaTEM-1 were common ESBL genotypes. The wzi typing method could further subdivide ST11 KP group into at least five subgroups, among which wzi209 (69.83%, 442/633) was the most frequently isolated, followed by wzi141 (25.28%, 160/633). Conjugation assays showed that high conjugation rates were observed in CPE (15.24%, 32/210) for NDM plasmids, but relatively low (8.1%, 17/210) for KPC-2 plasmids. Different STs, different wzis and temperature could influence plasmid conjugation efficiency. No associations between the rates of antibiotics consumption and CPE prevalence were observed. The number of intra-hospital and inter-hospital transfers of CPE patients increased gradually from 18 (17.82%, 101) and 12 (11.88%, 101) in 2015 to 63 (30.73%, 205) and 51 (24.88%, 205) in 2018 (p = 0.016 and p = 0.008), respectively. Evidence-based measures could effectively reduce the prevalence of ST11-wzi209 clone but failed to control the dissemination of ST11-wzi141 KP clone. Conclusions Clonal spread of CPE, especially KPC-2 ST11 KP was the key factor contributing to the CPE increase in the region. Continued vigilance for the importations should be maintained. Coordinated regional interventions are urgently needed to reduce CPE threat.
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Tarazi YH, El-Sukhon SN, Ismail ZB, Almestarehieh AA. Molecular characterization of enterohemorrhagic Escherichia coli isolated from diarrhea samples from human, livestock, and ground beef in North Jordan. Vet World 2021; 14:2827-2832. [PMID: 34903945 PMCID: PMC8654754 DOI: 10.14202/vetworld.2021.2827-2832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/30/2021] [Indexed: 11/22/2022] Open
Abstract
Background and Aim: Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen with worldwide distribution. Data regarding its presence, distribution, virulence, and antimicrobial susceptibility among various animal species and humans in Jordan are lacking. Therefore, the objectives of this study were to isolate and characterize EHEC from human and animal diarrhea fecal samples and ground beef samples. Materials and Methods: A total of 100 and 270 diarrhea fecal samples from humans and animals, respectively, were collected. In addition, 40 ground beef meat samples were collected from retail markets. EHEC was positively identified by detecting Shiga toxins (stx1 and stx2) genes using multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility patterns were determined using the disk diffusion test. Beta-lactamase production was detected using the double disk diffusion test and the extended-spectrum beta-lactamases (ESBLs) were identified by detection of blaTEM, blaSHV, and OXA-1 genes using multiplex PCR. Pulsed-field gel electrophoresis (PFGE) was used to investigate the relatedness of EHEC isolates from different sources. Results: Out of 410 samples, 194 E. coli isolates were positively identified, of which 57 isolates (29%) were classified as EHEC. Thirty-five (61%) of EHEC isolates were serotyped as O157 (19: O157:H7 and 16: O157:NM). The stx1 gene was detected only among the sheep and goats isolates at a rate of 7.6% and 5.2%, respectively, while the stx2 gene was detected in only one ground beef meat sample. EHEC isolates showed high resistance patterns against amoxicillin, gentamycin, cephalexin, and doxycycline. Twenty-four out of 32 EHEC isolates were determined as ESBL producers, among which 14 isolates expressed the blaSHVgene and 19 isolates expressed the blaTEM while four expressed both genes. PFGE analysis revealed two clusters with high similarity (92%) originated from ground beef meat and cattle fecal samples. No similarities were found between human and animal E. coli isolates. Conclusion: Results of this study indicate widespread ESBL EHEC among humans, animals, and ground beef meat samples. These results represent an important alarm that requires the implementation of appropriate preventative measures by both human and animal health sectors to prevent the transmission of this important foodborne pathogen.
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Affiliation(s)
- Yaser H Tarazi
- Department of Basic Medical Veterinary Sciences, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Saeb N El-Sukhon
- Department of Basic Medical Veterinary Sciences, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Zuhair Bani Ismail
- Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Amani A Almestarehieh
- Department of Basic Medical Veterinary Sciences, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan
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Prevalence and Whole-Genome Sequence-Based Analysis of Shiga Toxin-Producing Escherichia coli Isolates from the Recto-Anal Junction of Slaughter-Age Irish Sheep. Appl Environ Microbiol 2021; 87:e0138421. [PMID: 34644161 DOI: 10.1128/aem.01384-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) organisms are a diverse group of pathogenic bacteria capable of causing serious human illness, and serogroups O157 and O26 are frequently implicated in human disease. Ruminant hosts are the primary STEC reservoir, and small ruminants are important contributors to STEC transmission. This study investigated the prevalence, serotypes, and shedding dynamics of STEC, including the supershedding of serogroups O157 and O26, in Irish sheep. Recto-anal mucosal swab samples (n = 840) were collected over 24 months from two ovine slaughtering facilities. Samples were plated on selective agars and were quantitatively and qualitatively assessed via real-time PCR (RT-PCR) for Shiga toxin prevalence and serogroup. A subset of STEC isolates (n = 199) were selected for whole-genome sequencing and analyzed in silico. In total, 704/840 (83.8%) swab samples were Shiga toxin positive following RT-PCR screening, and 363/704 (51.6%) animals were subsequently culture positive for STEC. Five animals were shedding STEC O157, and three of these were identified as supershedders. No STEC O26 was isolated. Post hoc statistical analysis showed that younger animals are more likely to harbor STEC and that STEC carriage is most prevalent during the summer months. Following sequencing, 178/199 genomes were confirmed as STEC. Thirty-five different serotypes were identified, 15 of which were not yet reported for sheep. Serotype O91:H14 was the most frequently reported. Eight Shiga toxin gene variants were reported, two stx1 and six stx2, and three novel Shiga-toxin subunit combinations were observed. Variant stx1c was the most prevalent, while many strains also harbored stx2b. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) bacteria are foodborne, zoonotic pathogens of significant public health concern. All STEC organisms harbor stx, a critical virulence determinant, but it is not expressed in most serotypes. Sheep shed the pathogen via fecal excretion and are increasingly recognized as important contributors to the dissemination of STEC. In this study, we have found that there is high prevalence of STEC circulating within sheep and that prevalence is related to animal age and seasonality. Further, sheep harbor a variety of non-O157 STEC, whose prevalence and contribution to human disease have been underinvestigated for many years. A variety of Stx variants were also observed, some of which are of high clinical importance.
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Abstract
Diarrheal disease is still a major public health concern, as it is still considered an important cause of death in children under five years of age. A few decades ago, the detection of enteropathogenic E. coli was made by detecting the O, H, and K antigens, mostly by agglutination. The recent protocols recommend the molecular methods for diagnosing EPEC, as they can distinguish between typical and atypical EPEC by identifying the presence/absence of specific virulence factors. EPEC are defined as diarrheagenic strains of E. coli that can produce attaching and effacing lesions on the intestinal epithelium while being incapable of producing Shiga toxins and heat-labile or heat-stable enterotoxins. The ability of these strains to produce attaching and effacing lesions enable them to cause localized lesions by attaching tightly to the surface of the intestinal epithelial cells, disrupting the surfaces of the cells, thus leading to the effacement of the microvilli. EPEC are classified on typical and atypical isolates, based on the presence or absence of E. coli adherence factor plasmids. All the EPEC strains are eae positive; typical EPEC strains are eae+, bfpA+, while atypical strains are eae+, bfpA−. No vaccines are currently available to prevent EPEC infections.
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Farahani O, Ranjbar R, Honarmand Jahromy S, Arabzadeh B. Multilocus Variable-Number Tandem-Repeat Analysis for Geno-typing of Escherichia coli Strains Isolated from Hospital Wastewater, Tehran, Iran. IRANIAN JOURNAL OF PUBLIC HEALTH 2020; 49:2409-2417. [PMID: 34178748 PMCID: PMC8215070 DOI: 10.18502/ijph.v49i12.4829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background: Escherichia coli is one of the most frequent causes of many common bacterial infections. As a potential reservoir, hospital wastewater is considered for the dissemination of bacterial pathogens such as E. coli. Therefore, research on hospital waste’s bacteria by low-cost, rapid and easy molecular typing methods such as multilocus variable-number tandem-repeat analysis (MLVA) can be helpful for the study of epidemics. Methods: E. coli strains were isolated from hospital wastewater sources in Tehran, Iran, over a 24-month sampling period (Jun 2014- Jun 2016) and identified by standard bacteriological methods. The diversity of repeated sequences of seven variable-number tandem-repeat (VNTR) loci was studied by MLVA method base on polymerase chain reaction (PCR). Results: Overall, 80 E. coli isolates were discriminated into 51 different genotypes. Analysis of the MLVA profiles using a minimum spanning tree (MST) algorithm showed two clonal complexes with 71 isolates and only nine isolates were stayed out of clonal complexes in the form of a singleton. High genotypic diversity was seen among E. coli strains isolated from hospital wastewaters; however, a large number of isolates showed a close genetic relationship. Conclusion: MLVA showed to be a rapid, inexpensive and useful tool for the analysis of the phylogenetic relationships between E. coli strains under the study.
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Affiliation(s)
- Omid Farahani
- Department of Microbiology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran
| | - Reza Ranjbar
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | | | - Bahareh Arabzadeh
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Prevalence of Extended-Spectrum β-Lactamases Among Klebsiella pneumoniae Isolated from Intensive Care Unit Patients in a Tertiary Hospital. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2019. [DOI: 10.5812/archcid.69199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Milton AAP, Agarwal RK, Priya GB, Aravind M, Athira CK, Rose L, Saminathan M, Sharma AK, Kumar A. Captive wildlife from India as carriers of Shiga toxin-producing, Enteropathogenic and Enterotoxigenic Escherichia coli. J Vet Med Sci 2018; 81:321-327. [PMID: 30393267 PMCID: PMC6395213 DOI: 10.1292/jvms.18-0488] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) make up an important group of pathogens causing major animal and public health concerns worldwide. The aim of this study was to determine the prevalence of different pathotypes of E. coli in captive wildlife. We analyzed 314 fresh fecal samples from captive wildlife, 30 stool swabs from animal caretakers, and 26 feed and water samples collected from various zoological gardens and enclosures in India for the isolation of E. coli, followed by pathotyping by multiplex PCR. The overall occurrence rate of E. coli was 74.05% (274/370). The 274 E. coli isolates were pathotyped by multiplex PCR targeting 6 genes. Of them, 5.83% were pathotyped as EPEC, 4.74% as STEC, and 1.09% as ETEC. The 16S rRNA genes from the selected isolates were amplified, sequenced, and a phylogenetic tree was constructed. The phylogenetic tree exhibited indiscriminate genetic profiling and some isolates from captive wild animals had 100% genetic identity with isolates from caretakers, suggesting that captive wildlife may serve as a reservoir for infection in humans and vice-versa. The present study demonstrates for the first time the prevalence of these E. coli pathotypes in captive wildlife in India. Our study suggests that atypical EPEC strains are more frequent than typical EPEC strains in captive wildlife. Discovering the implications of the prevalence of these pathotypes in wildlife conservation is a challenging topic to be addressed by further investigations.
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Affiliation(s)
- Arockiasamy Arun Prince Milton
- Division of Veterinary Public Health, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Rajesh Kumar Agarwal
- Division of Bacteriology and Mycology, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Govindarajan Bhuvana Priya
- Division of Bacteriology and Mycology, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Manivasagam Aravind
- Department of Veterinary Parasitology, Madras Veterinary College, Chennai-600007, Tamil Nadu, India
| | - Cheruplackal Karunakaran Athira
- Division of Veterinary Public Health, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Losa Rose
- Division of Bacteriology and Mycology, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Mani Saminathan
- Division of Pathology, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Anil Kumar Sharma
- Division of Pathology, Indian Council of Agricultural Research (ICAR)-Indian Veterinary Research Institute, Izatnagar, Bareilly-243122, Uttar Pradesh, India
| | - Ashok Kumar
- Division of Animal Science, Indian Council of Agricultural Research (ICAR), Krishi Bhavan, New Delhi, India
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Santos ECCD, Castro VS, Cunha-Neto A, Santos LFD, Vallim DC, Lisbôa RDC, Carvalho RCT, Junior CAC, Figueiredo EEDS. Escherichia coli O26 and O113:H21 on Carcasses and Beef from a Slaughterhouse Located in Mato Grosso, Brazil. Foodborne Pathog Dis 2018; 15:653-659. [PMID: 30036077 DOI: 10.1089/fpd.2018.2431] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a group of emerging pathogens that can cause human diseases, including hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). Monitoring slaughtering stages and checking contamination points are crucial for the production of safe food. In this context, the aim of this study was to verify contamination by STEC strains, to determine the contamination points and evaluate the resistance profile to 12 antimicrobials used in both veterinary and human medicine. A total of 80 samples were obtained from eight collection points (pen floor, rectum, hide, carcass swabs and esophagus, diaphragm, masseter, and retail beef tissue samples). The isolates were collected by dilution plating on MacConkey agar with sorbitol, cefixime, and tellurite and analyzed by multiplex polymerase chain reaction for virulence genes. Serotyping of non-O157 was performed, and testing for 12 antibiotics by disk diffusion was carried out. A total of 18 STEC strains were isolated, presenting different virulence profiles. Contamination by STEC was observed in the rectum (5/18), carcass surface (5/18), hide (3/18), diaphragm (2/18), retail beef (2/18), and masseter muscle (1/18). Pen floor swabs and esophagus tissues showed no STEC contamination. Moreover, three strains were identified as O26 and three as O113:H21 strains, which have been linked to HUS and HC outbreak cases in Brazil. All STEC isolates were susceptible to all evaluated antimicrobials, except streptomycin. The presence of STEC strains is a direct risk to the consumer, especially when isolated from retail beef, and contamination can occur during different slaughter stages. However, antimicrobial resistance profiles did not identify multidrug-resistant strains, limiting potential antimicrobial resistance transmission to other pathogens.
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Affiliation(s)
| | - Vinicius Silva Castro
- 2 Instituto de Química , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adelino Cunha-Neto
- 3 Programa de Pós graduação Nutrição, Alimentos e Metabolismo, Universidade Federal de Mato Grosso , Cuiabá, Brazil .,4 Faculdade de Veterinária, Universidade Federal Fluminense , Rio de Janeiro, Brazil
| | - Luis Fernando Dos Santos
- 5 Instituto Adolf Lutz , Núcleo de Doenças Entéricas e Infecções por Patógenos Especiais, São Paulo, Brazil
| | | | | | | | - Carlos Adam Conte Junior
- 2 Instituto de Química , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .,4 Faculdade de Veterinária, Universidade Federal Fluminense , Rio de Janeiro, Brazil .,6 Instituto Oswaldo Cruz , Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Eduardo Eustáquio de Souza Figueiredo
- 1 Programa de Pós graduação em Ciência Animal, Universidade Federal de Mato Grosso , Cuiabá, Brazil .,3 Programa de Pós graduação Nutrição, Alimentos e Metabolismo, Universidade Federal de Mato Grosso , Cuiabá, Brazil
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Multiple-Locus Variable Number Tandem Repeat Analysis ofKlebsiella pneumoniae: Comparison with Pulsed-Field Gel Electrophoresis. Microb Drug Resist 2017; 23:626-632. [DOI: 10.1089/mdr.2016.0107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim NH, Cho TJ, Rhee MS. Current Interventions for Controlling Pathogenic Escherichia coli. ADVANCES IN APPLIED MICROBIOLOGY 2017; 100:1-47. [PMID: 28732552 DOI: 10.1016/bs.aambs.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
This review examined scientific reports and articles published from 2007 to 2016 regarding the major environmental sources of pathogenic Escherichia coli and the routes by which they enter the human gastrointestinal tract. The literature describes novel techniques used to combat pathogenic E. coli transmitted to humans from livestock and agricultural products, food-contact surfaces in processing environments, and food products themselves. Although prevention before contamination is always the best "intervention," many studies aim to identify novel chemical, physical, and biological techniques that inactivate or eliminate pathogenic E. coli cells from breeding livestock, growing crops, and manufactured food products. Such intervention strategies target each stage of the food chain from the perspective of "Farm to Table food safety" and aim to manage major reservoirs of pathogenic E. coli throughout the entire process. Issues related to, and recent trends in, food production must address not only the safety of the food itself but also the safety of those who consume it. Thus, research aims to discover new "natural" antimicrobial agents and to develop "multiple hurdle technology" or other novel technologies that preserve food quality. In addition, this review examines the practical application of recent technologies from the perspective of product quality and safety. It provides comprehensive insight into intervention measures used to ensure food safety, specifically those aimed at pathogenic E. coli.
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Affiliation(s)
- Nam Hee Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Tae Jin Cho
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Min Suk Rhee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
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Derakhshan S, Peerayeh SN, Bakhshi B. Genotyping and characterization of CTX-M-15 -producing Klebsiella pneumoniae isolated from an Iranian hospital. J Chemother 2017; 28:289-96. [PMID: 25734924 DOI: 10.1179/1973947815y.0000000002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The aims were to describe the genetic characterization of blaCTX-M-1 group gene in Klebsiella pneumoniae and to investigate the relationship between isolates by MLVA and PFGE. We analyzed 36 CTX-M group 1-ESBL producing K. pneumoniae. rmpA and wcaG virulence genes were identified by PCR. The genetic environment of blaCTX-M-1 was analyzed by PCR and sequencing. Plasmid replicons were determined using PCR-based replicon typing. The isolates were typed by MLVA and PFGE. All blaCTX-M-1 were blaCTX-M-15. The wcaG and rmpA were detected in 1 and 2 isolates, respectively. IncF were the most frequently detected replicons (63.88%). In all isolates, ISEcp1 was found upstream and orf477 downstream of blaCTX-M-15, IS26 was found in two isolates. MLVA identified 20 MLVA types, whereas PFGE identified 25 different profiles. The dissemination of CTX-M-15 in our isolates was due to the clonal spread of isolates and to the genetic transfer of mobile elements among unrelated strains.
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Affiliation(s)
- Safoura Derakhshan
- a Department of Bacteriology, Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Shahin Najar Peerayeh
- a Department of Bacteriology, Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Bita Bakhshi
- a Department of Bacteriology, Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
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Strain Typing and Molecular Characterization of CTX-M-1 Group ESBL in Clinical Klebsiella pneumoniae Isolated from Children. ARCHIVES OF PEDIATRIC INFECTIOUS DISEASES 2016. [DOI: 10.5812/pedinfect.39193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Escherichia coli O104 in Feedlot Cattle Feces: Prevalence, Isolation and Characterization. PLoS One 2016; 11:e0152101. [PMID: 27010226 PMCID: PMC4807062 DOI: 10.1371/journal.pone.0152101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/08/2016] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli O104:H4, an hybrid pathotype of Shiga toxigenic and enteroaggregative E. coli, involved in a major foodborne outbreak in Germany in 2011, has not been detected in cattle feces. Serogroup O104 with H type other than H4 has been reported to cause human illnesses, but their prevalence and characteristics in cattle have not been reported. Our objectives were to determine the prevalence of E. coli O104 in feces of feedlot cattle, by culture and PCR detection methods, and characterize the isolated strains. Rectal fecal samples from a total of 757 cattle originating from 29 feedlots were collected at a Midwest commercial slaughter plant. Fecal samples, enriched in E. coli broth, were subjected to culture and PCR methods of detection. The culture method involved immunomagnetic separation with O104-specific beads and plating on a selective chromogenic medium, followed by serogroup confirmation of pooled colonies by PCR. If pooled colonies were positive for the wzxO104 gene, then colonies were tested individually to identify wzxO104-positive serogroup and associated genes of the hybrid strains. Extracted DNA from feces were also tested by a multiplex PCR to detect wzxO104-positive serogroup and associated major genes of the O104 hybrid pathotype. Because wzxO104 has been shown to be present in E. coli O8/O9/O9a, wzxO104-positive isolates and extracted DNA from fecal samples were also tested by a PCR targeting wbdDO8/O9/O9a, a gene specific for E. coli O8/O9/O9a serogroups. Model-adjusted prevalence estimates of E. coli O104 (positive for wzxO104 and negative for wbdDO8/O9/O9a) at the feedlot level were 5.7% and 21.2%, and at the sample level were 0.5% and 25.9% by culture and PCR, respectively. The McNemar's test indicated that there was a significant difference (P < 0.01) between the proportions of samples that tested positive for wzxO104 and samples that were positive for wzxO104, but negative for wbdDO8/O9/O9a by PCR and culture methods. A total of 143 isolates, positive for the wzxO104, were obtained in pure culture from 146 positive fecal samples. Ninety-two of the 143 isolates (64.3%) also tested positive for the wbdDO8/O9/O9a, indicating that only 51 (35.7%) isolates truly belonged to the O104 serogroup (positive for wzxO104 and negative for wbdDO8/O9/O9a). All 51 isolates tested negative for eae, and 16 tested positive for stx1 gene of the subtype 1c. Thirteen of the 16 stx1-positive O104 isolates were from one feedlot. The predominant serotype was O104:H7. Pulsed-field gel electrophoresis analysis indicated that stx1-positive O104:H7 isolates had 62.4% homology to the German outbreak strain and 67.9% to 77.5% homology to human diarrheagenic O104:H7 strains. The 13 isolates obtained from the same feedlot were of the same PFGE subtype with 100% Dice similarity. Although cattle do not harbor the O104:H4 pathotype, they do harbor and shed Shiga toxigenic O104 in the feces and the predominant serotype was O104:H7.
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Duffy G, McCabe E. Veterinary Public Health Approach to Managing Pathogenic Verocytotoxigenic Escherichia coli in the Agri-Food Chain. Microbiol Spectr 2014; 2. [PMID: 26104349 DOI: 10.1128/microbiolspec.ehec-0023-2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Verocytoxigenic Escherichia coli (VTEC) comprises many diverse serogroups, but seven serogroups, O157, O26, O103, O145, O111, O21, and O45, have been most commonly linked to severe human infections, though illness has also been reported from a range of other VTEC serogroups. This poses challenges in assessing the risk to humans from the diverse range of VTEC strains that may be recovered from animals, the environment, or food. For routine assessment of risk posed by VTEC recovered from the agri-food chain, the concept of seropathotype can be used to rank the human risk potential from a particular VTEC serogroup on the basis of both serotype (top seven serogroups) and the presence of particular virulence genes (vt in combination with eae, or aaiC plus aggR). But for other VTEC serogroups or virulence gene combinations, it is not currently possible to fully assess the risk posed. VTEC is shed in animal feces and can persist in the farm environment for extended periods ranging from several weeks to many months, posing an ongoing reservoir of contamination for grazing animals, water courses, and fresh produce and for people using farmland for recreational purposes. Appropriate handling and treatment of stored animal waste (slurries and manures) will reduce risk from VTEC in the farm environment. Foods of animal origin such as milk and dairy products and meat may be contaminated with VTEC during production and processing, and the pathogen may survive or grow during processing operations, highlighting the need for well-designed and validated Hazard Analysis Critical Control Point management systems. This article focuses on a veterinary public health approach to managing VTEC, highlighting the various routes in the agri-food chain for transmission of human pathogenic VTEC and general approaches to managing the risk.
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Affiliation(s)
| | - Evonne McCabe
- Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
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Nesse LL, Sekse C, Berg K, Johannesen KCS, Solheim H, Vestby LK, Urdahl AM. Potentially pathogenic Escherichia coli can form a biofilm under conditions relevant to the food production chain. Appl Environ Microbiol 2014; 80:2042-9. [PMID: 24362422 PMCID: PMC3993160 DOI: 10.1128/aem.03331-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/13/2013] [Indexed: 12/11/2022] Open
Abstract
The biofilm-producing abilities of potentially human-pathogenic serotypes of Escherichia coli from the ovine reservoir were studied at different temperatures and on different surfaces. A possible influence of the hydrophobicity of the bacterial cells, as well as the presence of two virulence factors, the Shiga toxin-encoding (Stx) bacteriophage and the eae gene, was also studied. A total of 99 E. coli isolates of serotypes O26:H11, O103:H2, and O103:H25 isolated from sheep feces were included. The results show that isolates of all three E. coli serotypes investigated can produce biofilm on stainless steel, glass, and polystyrene at 12, 20, and 37°C. There was a good general correlation between the results obtained on the different surfaces. E. coli O103:H2 isolates produced much more biofilm than those of the other two serotypes at all three temperatures. In addition, isolates of serotype O26:H11 produced more biofilm than those of O103:H25 at 37°C. The hydrophobicity of the isolates varied between serotypes and was also influenced by temperature. The results strongly indicated that hydrophobicity influenced the attachment of the bacteria rather than their ability to form biofilm once attached. Isolates with the eae gene produced less biofilm at 37°C than isolates without this gene. The presence of a Stx bacteriophage did not influence biofilm production. In conclusion, our results show that potentially human-pathogenic E. coli from the ovine reservoir can form biofilm on various surfaces and at several temperatures relevant for food production and handling.
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Affiliation(s)
- Live L. Nesse
- Section for Bacteriology—Aquatic and Terrestrial, Norwegian Veterinary Institute, Oslo, Norway
| | - Camilla Sekse
- Section for Bacteriology—Aquatic and Terrestrial, Norwegian Veterinary Institute, Oslo, Norway
| | - Kristin Berg
- Section for Bacteriology—Aquatic and Terrestrial, Norwegian Veterinary Institute, Oslo, Norway
| | | | - Heidi Solheim
- Section for Bacteriology—Aquatic and Terrestrial, Norwegian Veterinary Institute, Oslo, Norway
| | - Lene K. Vestby
- Section for Bacteriology—Aquatic and Terrestrial, Norwegian Veterinary Institute, Oslo, Norway
| | - Anne Margrete Urdahl
- Section for Veterinary Public Health, Norwegian Veterinary Institute, Oslo, Norway
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Paddock ZD, Renter DG, Cull CA, Shi X, Bai J, Nagaraja TG. Escherichia coliO26 in Feedlot Cattle: Fecal Prevalence, Isolation, Characterization, and Effects of anE. coliO157 Vaccine and a Direct-Fed Microbial. Foodborne Pathog Dis 2014; 11:186-93. [DOI: 10.1089/fpd.2013.1659] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Zac D. Paddock
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas
| | - David G. Renter
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas
| | - Charley A. Cull
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas
| | - Xiarong Shi
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas
| | - Jianfa Bai
- Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, Kansas
| | - Tiruvoor G. Nagaraja
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas
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Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 823] [Impact Index Per Article: 74.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
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Occurrence of potentially human-pathogenic Escherichia coli O103 in Norwegian sheep. Appl Environ Microbiol 2013; 79:7502-9. [PMID: 24077709 DOI: 10.1128/aem.01825-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The investigation of an outbreak of hemorrhagic-uremic syndrome in Norway in 2006 indicated that the outbreak strain Escherichia coli O103:H25 could originate from sheep. A national survey of the Norwegian sheep population was performed, with the aim of identifying and describing a possible reservoir of potentially human-pathogenic E. coli O103, in particular of the H types 2 and 25. The investigation of fecal samples from 585 sheep flocks resulted in 1,222 E. coli O103 isolates that were analyzed for the presence of eae and stx genes, while a subset of 369 isolates was further examined for flagellar antigens (H typing), stx subtypes, bfpA, astA, and molecular typing by pulsed-field gel electrophoresis (PFGE). The total ovine E. coli O103 serogroup was genetically diverse by numbers of H types, virulotypes, and PFGE banding patterns identified, although a tendency of clustering toward serotypes was seen. The flocks positive for potentially human-pathogenic E. coli O103 were geographically widely distributed, and no association could be found with county or geographical region. The survey showed that eae-negative, stx-negative E. coli O103, probably nonpathogenic to humans, is very common in sheep, with 27.5% of flocks positive. Moreover, the study documented a low prevalence (0.7%) of potentially human-pathogenic Shiga toxin-producing E. coli O103:H2, while STEC O103:H25 was not detected. However, 3.1% and 5.8% of the flocks were positive for enteropathogenic E. coli O103 belonging to H types 2 and 25, respectively. These isolates are of concern as potential human pathogens by themselves but more importantly as possible precursors for human-pathogenic STEC.
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19
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Host-Microbe Interactions in Caenorhabditis elegans. ISRN MICROBIOLOGY 2013; 2013:356451. [PMID: 23984180 PMCID: PMC3747393 DOI: 10.1155/2013/356451] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/16/2013] [Indexed: 01/09/2023]
Abstract
A good understanding of how microbes interact with hosts has a direct bearing on our capability of fighting infectious microbial pathogens and making good use of beneficial ones. Among the model organisms used to study reciprocal actions among microbes and hosts, C. elegans may be the most advantageous in the context of its unique attributes such as the short life cycle, easiness of laboratory maintenance, and the availability of different genetic mutants. This review summarizes the recent advances in understanding host-microbe interactions in C. elegans. Although these investigations have greatly enhanced our understanding of C. elegans-microbe relationships, all but one of them involve only one or few microbial species. We argue here that more research is needed for exploring the evolution and establishment of a complex microbial community in the worm's intestine and its interaction with the host.
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20
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Technical specifications on harmonised epidemiological indicators for biological hazards to be covered by meat inspection of domestic sheep and goats. EFSA J 2013. [DOI: 10.2903/j.efsa.2013.3277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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21
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Paddock ZD, Bai J, Shi X, Renter DG, Nagaraja TG. Detection of Escherichia coli O104 in the feces of feedlot cattle by a multiplex PCR assay designed to target major genetic traits of the virulent hybrid strain responsible for the 2011 German outbreak. Appl Environ Microbiol 2013; 79:3522-5. [PMID: 23542615 PMCID: PMC3648041 DOI: 10.1128/aem.00246-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/22/2013] [Indexed: 01/22/2023] Open
Abstract
A multiplex PCR was designed to detect Escherichia coli O104:H4, a hybrid pathotype of Shiga toxigenic and enteroaggregative E. coli, in cattle feces. A total of 248 fecal samples were tested, and 20.6% were positive for serogroup O104. The O104 isolates did not carry genes characteristic of the virulent hybrid strain.
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Affiliation(s)
| | - J. Bai
- Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, Kansas, USA
| | - X. Shi
- Department of Diagnostic Medicine and Pathobiology
| | - D. G. Renter
- Department of Diagnostic Medicine and Pathobiology
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22
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Abstract
A risk ranking process identified Toxoplasma gondii and pathogenic verocytotoxin-producing Escherichia coli (VTEC) as the most relevant biological hazards for meat inspection of sheep and goats. As these are not detected by traditional meat inspection, a meat safety assurance system using risk-based interventions was proposed. Further studies are required on T. gondii and pathogenic VTEC. If new information confirms these hazards as a high risk to public health from meat from sheep or goats, setting targets at carcass level should be considered. Other elements of the system are risk-categorisation of flocks/herds based on improved Food Chain Information (FCI), classification of abattoirs according to their capability to reduce faecal contamination, and use of improved process hygiene criteria. It is proposed to omit palpation and incision from post-mortem inspection in animals subjected to routine slaughter. For chemical hazards, dioxins and dioxin-like polychlorinated biphenyls were ranked as being of high potential concern. Monitoring programmes for chemical hazards should be more flexible and based on the risk of occurrence, taking into account FCI, which should be expanded to reflect the extensive production systems used, and the ranking of chemical substances, which should be regularly updated and include new hazards. Control programmes across the food chain, national residue control plans, feed control and monitoring of environmental contaminants should be better integrated. Meat inspection is a valuable tool for surveillance and monitoring of animal health and welfare conditions. Omission of palpation and incision would reduce detection effectiveness for tuberculosis and fasciolosis at animal level. Surveillance of tuberculosis at the slaughterhouse in small ruminants should be improved and encouraged, as this is in practice the only surveillance system available. Extended use of FCI could compensate for some, but not all, the information on animal health and welfare lost if only visual post-mortem inspection is applied.
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Schilling AK, Hotzel H, Methner U, Sprague LD, Schmoock G, El-Adawy H, Ehricht R, Wöhr AC, Erhard M, Geue L. Zoonotic agents in small ruminants kept on city farms in southern Germany. Appl Environ Microbiol 2012; 78:3785-93. [PMID: 22447607 PMCID: PMC3346384 DOI: 10.1128/aem.07802-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 03/05/2012] [Indexed: 11/20/2022] Open
Abstract
Sheep and goats are popular examples of livestock kept on city farms. In these settings, close contacts between humans and animals frequently occur. Although it is widely accepted that small ruminants can carry numerous zoonotic agents, it is unknown which of these agents actually occur in sheep and goats on city farms in Germany. We sampled feces and nasal liquid of 48 animals (28 goats, 20 sheep) distributed in 7 city farms and on one activity playground in southern Germany. We found that 100% of the sampled sheep and 89.3% of the goats carried Shiga toxin-producing Escherichia coli (STEC). The presence of Staphylococcus spp. in 75% of both sheep and goats could be demonstrated. Campylobacter spp. were detected in 25% and 14.3% of the sheep and goats, respectively. Neither Salmonella spp. nor Coxiella burnetii was found. On the basis of these data, we propose a reasonable hygiene scheme to prevent transmission of zoonotic agents during city farm visits.
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Affiliation(s)
- Anna-Katarina Schilling
- Ludwig-Maximilians-Universität Munich, Faculty of Veterinary Medicine, Department of Veterinary Sciences, Munich, Germany
| | - Helmut Hotzel
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Ulrich Methner
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Lisa D. Sprague
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Gernot Schmoock
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Hosny El-Adawy
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | | | - Anna-Caroline Wöhr
- Ludwig-Maximilians-Universität Munich, Faculty of Veterinary Medicine, Department of Veterinary Sciences, Munich, Germany
| | - Michael Erhard
- Ludwig-Maximilians-Universität Munich, Faculty of Veterinary Medicine, Department of Veterinary Sciences, Munich, Germany
| | - Lutz Geue
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Wusterhausen, Germany
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Norwegian sheep are an important reservoir for human-pathogenic Escherichia coli O26:H11. Appl Environ Microbiol 2012; 78:4083-91. [PMID: 22492457 DOI: 10.1128/aem.00186-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A previous national survey of Escherichia coli in Norwegian sheep detected eae-positive (eae(+)) E. coli O26:H11 isolates in 16.3% (80/491) of the flocks. The purpose of the present study was to evaluate the human-pathogenic potential of these ovine isolates by comparing them with E. coli O26 isolates from humans infected in Norway. All human E. coli O26 isolates studied carried the eae gene and shared flagellar type H11. Two-thirds of the sheep flocks and 95.1% of the patients harbored isolates containing arcA allele type 2 and espK and were classified as enterohemorrhagic E. coli (EHEC) (stx positive) or EHEC-like (stx negative). These isolates were further divided into group A (EspK2 positive), associated with stx(2-EDL933) and stcE(O103), and group B (EspK1 positive), associated with stx(1a). Although the stx genes were more frequently present in isolates from patients (46.3%) than in those from sheep flocks (5%), more than half of the ovine isolates in the EHEC/EHEC-like group had multiple-locus variable number of tandem repeat analysis (MLVA) profiles that were identical to those seen in stx-positive human O26:H11 isolates. This indicates that EHEC-like ovine isolates may be able to acquire stx-carrying bacteriophages and thereby have the possibility to cause serious illness in humans. The remaining one-third of the sheep flocks and two of the patients had isolates fulfilling the criteria for atypical enteropathogenic E. coli (aEPEC): arcA allele type 1 and espK negative (group C). The majority of these ovine isolates showed MLVA profiles not previously seen in E. coli O26:H11 isolates from humans. However, according to their virulence gene profile, the aEPEC ovine isolates should be considered potentially pathogenic for humans. In conclusion, sheep are an important reservoir of human-pathogenic E. coli O26:H11 isolates in Norway.
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Løbersli I, Haugum K, Lindstedt BA. Rapid and high resolution genotyping of all Escherichia coli serotypes using 10 genomic repeat-containing loci. J Microbiol Methods 2011; 88:134-9. [PMID: 22088357 DOI: 10.1016/j.mimet.2011.11.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/21/2011] [Accepted: 11/01/2011] [Indexed: 10/15/2022]
Abstract
Our laboratory has previously published two multiple-locus variable-number tandem-repeats analysis (MLVA) methods for rapid genotyping of Escherichia coli (E. coli), which are now in routine use for surveillance and outbreak detection. The first assay developed was specific for E. coli O157:H7; however this assay was not suitable for genotyping other E. coli serotypes. A new generic MLVA-assay was then developed with the capability of genotyping all E. coli serotypes. This generic E. coli MLVA (GECM7) was based on polymorphism in seven variable number of tandem repeats (VNTR) loci. GECM7 worked well with the majority of E. coli serotypes; however we wanted to increase the resolution for this method based in part of comparison with PFGE typing of E. coli O26:H11, where PFGE appeared to display higher resolution. The GECM7 method was improved by adding three new repeat-loci to a total of ten (GECM10), and a considerable increase in resolution was observed (from 296 to 507 genotypes on the same set of strains).
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Affiliation(s)
- Inger Løbersli
- Division of Infectious Diseases control, Norwegian Institute of Public Health, Lovisenberggata 8, P.O. Box 4404 Nydalen, N-0403 Oslo, Norway
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