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Solís-Sánchez P, Fernández-Martínez M, Rodrigo-Calabia E, de Alegría-Puig CR. Chronic Diarrhea Due to Aeromonas hydrophila in an Immunosuppressed Patient with a Pancreas-Kidney Transplant. Pathogens 2023; 12:1151. [PMID: 37764959 PMCID: PMC10536218 DOI: 10.3390/pathogens12091151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
The genus Aeromonas belongs to the Aeromonadaceae family. A patient with a pancreas-kidney transplant had multiple episodes of abdominal sepsis after surgery. Aeromonas hydrophila was isolated in the ascitic and biliary fluid drains. After discharge, the patient had several diarrhea episodes, and A. hydrophila was isolated in four stool samples. We decided to test whether the one strain that we initially isolated in ascitic fluid was the same that appeared in the successive stool samples. Five isolates of A. hydrophila were found in the patient. Identification was performed using the MALDI-TOF system and confirmed via multiplex PCR. The analysis of the REP-PCR fingerprint patterns showed one cluster and confirmed that all isolates were related. We also demonstrated the virulent character of this species associated with genes encoding different toxins (act, alt, ast, hlyA, and aerA). The virulence of this species is associated with the expression of genes that encode different toxins, structural proteins, and metal-associated proteins. This case report highlights the severity of this disease, especially in immunocompromised patients, and its adequate treatment.
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Affiliation(s)
- Pablo Solís-Sánchez
- Internal Medicine Service, University Hospital Marqués de Valdecilla-IDIVAL, 39008 Santander, Spain
| | | | - Emilio Rodrigo-Calabia
- Nephrology Service, University Hospital Marqués de Valdecilla-IDIVAL, 39008 Santander, Spain
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Occurrence of Virulence Genes and Antimicrobial Resistance of E. coli O157:H7 Isolated from the Beef Carcass of Bahir Dar City, Ethiopia. Vet Med Int 2021; 2021:8046680. [PMID: 34580607 PMCID: PMC8464425 DOI: 10.1155/2021/8046680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/26/2021] [Indexed: 11/17/2022] Open
Abstract
E. coli O157:H7 is one of the most virulent foodborne pathogens. The aim of this study was to isolate E. coli O157:H7, determine virulence genes carried by the organism, and assess the antimicrobial susceptibility pattern of the isolates from beef carcass samples at Bahir Dar city. Swab samples (n = 280) were collected from the carcass of cattle slaughtered at the abattoir and processed using sorbitol MacConkey agar supplemented with cefixime telluride and confirmed with latex agglutination test. A polymerase chain reaction was performed on isolates for the detection of virulence genes stx1, stx2, hlyA, and eae. Antimicrobial susceptibility testing was performed using the disk diffusion method. Of 280 samples processed, 25 (8.9%) isolates were positive. Out of 25 isolates subjected for molecular detection, 8 (32%) and 14 (56%) isolates possessed stx1 and stx2 genes, respectively; from those, 5 (20%) isolates had both genes for the production of Shiga toxins. Compared from other virulent genes relatively higher proportion of 18 (72%) isolates carried the hlyA gene. Only 5 (2%) isolates were positive for eae. Resistance was detected in all 25 (100%) isolates and 3 (12%) against clindamycin and trimethoprim, respectively. This study result highlights the potential threat to public health. The abattoir workers need to be aware about the pathogen and should follow appropriate practices to prevent contamination of meat intended for human consumption.
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Li B, Liu H, Wang W. Multiplex real-time PCR assay for detection of Escherichia coli O157:H7 and screening for non-O157 Shiga toxin-producing E. coli. BMC Microbiol 2017; 17:215. [PMID: 29121863 PMCID: PMC5679507 DOI: 10.1186/s12866-017-1123-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/27/2017] [Indexed: 12/22/2022] Open
Abstract
Background Shiga toxin-producing Escherichia coli (STEC), including E. coli O157:H7, are responsible for numerous foodborne outbreaks annually worldwide. E. coli O157:H7, as well as pathogenic non-O157:H7 STECs, can cause life-threating complications, such as bloody diarrhea (hemolytic colitis) and hemolytic-uremic syndrome (HUS). Previously, we developed a real-time PCR assay to detect E. coli O157:H7 in foods by targeting a unique putative fimbriae protein Z3276. To extend the detection spectrum of the assay, we report a multiplex real-time PCR assay to specifically detect E. coli O157:H7 and screen for non-O157 STEC by targeting Z3276 and Shiga toxin genes (stx1 and stx2). Also, an internal amplification control (IAC) was incorporated into the assay to monitor the amplification efficiency. Methods The multiplex real-time PCR assay was developed using the Life Technology ABI 7500 System platform and the standard chemistry. The optimal amplification mixture of the assay contains 12.5 μl of 2 × Universal Master Mix (Life Technology), 200 nM forward and reverse primers, appropriate concentrations of four probes [(Z3276 (80 nM), stx1 (80 nM), stx2 (20 nM), and IAC (40 nM)], 2 μl of template DNA, and water (to make up to 25 μl in total volume). The amplification conditions of the assay were set as follows: activation of TaqMan at 95 °C for 10 min, then 40 cycles of denaturation at 95 °C for 10 s and annealing/extension at 60 °C for 60 s. Results The multiplex assay was optimized for amplification conditions. The limit of detection (LOD) for the multiplex assay was determined to be 200 fg of bacterial DNA, which is equivalent to 40 CFU per reaction which is similar to the LOD generated in single targeted PCRs. Inclusivity and exclusivity determinants were performed with 196 bacterial strains. All E. coli O157:H7 (n = 135) were detected as positive and all STEC strains (n = 33) were positive for stx1, or stx2, or stx1 and stx2 (Table 1). No cross reactivity was detected with Salmonella enterica, Shigella strains, or any other pathogenic strains tested. Conclusions A multiplex real-time PCR assay that can rapidly and simultaneously detect E. coli O157:H7 and screen for non-O157 STEC strains has been developed and assessed for efficacy. The inclusivity and exclusivity tests demonstrated high sensitivity and specificity of the multiplex real-time PCR assay. In addition, this multiplex assay was shown to be effective for the detection of E. coli O157:H7 from two common food matrices, beef and spinach, and may be applied for detection of E. coli O157:H7 and screening for non-O157 STEC strains from other food matrices as well.
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Affiliation(s)
- Baoguang Li
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA.
| | - Huanli Liu
- Branch of Microbiology, Office of Regulatory Affairs, Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Weimin Wang
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
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Lapadula WJ, Ayub MJ. Ribosome Inactivating Proteins from an evolutionary perspective. Toxicon 2017; 136:6-14. [PMID: 28651991 DOI: 10.1016/j.toxicon.2017.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 01/13/2023]
Abstract
Ribosome Inactivating Proteins (RIPs) are rRNA N-glycosidases that inhibit protein synthesis through the elimination of a single adenine residue from 28S rRNA. Many of these toxins have been characterized in depth from a biochemical and molecular point of view. In addition, their potential use in medicine as highly selective toxins is being explored. In contrast, the evolutionary history of RIP encoding genes has remained traditionally underexplored. In recent years, accumulation of large genomic data has fueled research on this issue and revealed unexpected information about the origin and evolution of RIP toxins. In this review we summarize the current evidence available on the occurrence of different evolutionary mechanisms (gene duplication and losses, horizontal gene transfer, synthesis de novo and domain combination) involved in the evolution of the RIP gene family. Finally, we propose a revised nomenclature for RIP genes based on their evolutionary history.
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Affiliation(s)
- Walter Jesús Lapadula
- Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, IMIBIO-SL-CONICET, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
| | - Maximiliano Juri Ayub
- Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, IMIBIO-SL-CONICET, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
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Prakasan S, Prabhakar P, Lekshmi M, Kumar S, Nayak BB. Isolation of Shiga toxin-producing Escherichia coli harboring variant Shiga toxin genes from seafood. Vet World 2017; 11:379-385. [PMID: 29657433 PMCID: PMC5891856 DOI: 10.14202/vetworld.2018.379-385] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/21/2018] [Indexed: 01/06/2023] Open
Abstract
Background and Aim: Shiga toxin-producing Escherichia coli (STEC) are important pathogens of global significance. STEC are responsible for numerous food-borne outbreaks worldwide and their presence in food is a potential health hazard. The objective of the present study was to determine the incidence of STEC in fresh seafood in Mumbai, India, and to characterize STEC with respect to their virulence determinants. Materials and Methods: A total of 368 E. coli were isolated from 39 fresh seafood samples (18 finfish and 21 shellfish) using culture-based methods. The isolates were screened by polymerase chain reaction (PCR) for the genes commonly associated with STEC. The variant Shiga toxin genes were confirmed by Southern blotting and hybridization followed by DNA sequencing. Results: One or more Shiga toxins genes were detected in 61 isolates. Of 39 samples analyzed, 10 (25.64%) samples harbored STEC. Other virulence genes, namely, eaeA (coding for an intimin) and hlyA (hemolysin A) were detected in 43 and 15 seafood isolates, respectively. The variant stx1 genes from 6 isolates were sequenced, five of which were found to be stx1d variants, while one sequence varied considerably from known stx1 sequences. Southern hybridization and DNA sequence analysis suggested putative Shiga toxin variant genes (stx2) in at least 3 other isolates. Conclusion: The results of this study showed the occurrence of STEC in seafood harboring one or more Shiga toxin genes. The detection of STEC by PCR may be hampered due to the presence of variant genes such as the stx1d in STEC. This is the first report of stx1d gene in STEC isolated from Indian seafood.
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Affiliation(s)
- Sreepriya Prakasan
- Department of Post-Harvest Technology, Quality Control Laboratory, ICAR-Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India
| | - Parmanand Prabhakar
- Department of Post-Harvest Technology, Quality Control Laboratory, ICAR-Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India
| | - Manjusha Lekshmi
- Department of Post-Harvest Technology, Quality Control Laboratory, ICAR-Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India
| | - Sanath Kumar
- Department of Post-Harvest Technology, Quality Control Laboratory, ICAR-Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India
| | - Binaya Bhusan Nayak
- Department of Post-Harvest Technology, Quality Control Laboratory, ICAR-Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India
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Kwon T, Kim W, Cho SH. Comparative genomic analysis of Shiga toxin-producing and non-Shiga toxin-producing Escherichia coli O157 isolated from outbreaks in Korea. Gut Pathog 2017; 9:7. [PMID: 28191041 PMCID: PMC5292798 DOI: 10.1186/s13099-017-0156-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 01/24/2017] [Indexed: 12/01/2022] Open
Abstract
Background The Shiga toxin-producing Escherichia coli (STEC) O157 strain NCCP15739 and non-STEC O157 strain NCCP15738 were isolated from outbreaks in Korea. We characterized NCCP15739 and NCCP15738 by genome sequencing and a comparative genomic analysis using two additional strains, E. coli K-12 substr. MG1655 and O157:H7 EDL933. Results Using the Illumina HiSeq 2000 platform and the RAST server, the whole genomes of NCCP15739 and NCCP15738 were obtained and annotated. NCCP15739 and NCCP15738 clustered with different E. coli strains based on a whole-genome phylogeny and multi-locus sequence typing analysis. Functional annotation clustering indicated enrichment for virulence plasmid and hemolysis-related genes in NCCP15739 and conjugation- and flagellum-related genes in NCCP15738. Defense mechanism- and pathogenicity-related pathways were enriched in NCCP15739 and pathways related to the assimilation of energy sources were enriched in NCCP15738. We identified 66 and 18 virulence factors from the NCCP15739 and NCCP15738 genome, respectively. Five and eight antibiotic resistance genes were identified in the NCCP15739 and NCCP15738 genomes, respectively. Based on a comparative analysis of phage-associated regions, NCCP15739 and NCCP15738 had specific prophages. The prophages in NCCP15739 carried virulence factors, but those in NCCP15738 did not, and no antibiotic resistance genes were found in the phage-associated regions. Conclusions Our whole-genome sequencing and comparative genomic analysis revealed that NCCP15739 and NCCP15738 have specific genes and pathways. NCCP15739 had more genes (410), virulence factors (48), and phage-related regions (11) than NCCP15738. However, NCCP15738 had three more antibiotic resistance genes than NCCP15739. These differences may explain differences in pathogenicity and biological characteristics. Electronic supplementary material The online version of this article (doi:10.1186/s13099-017-0156-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Taesoo Kwon
- Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea.,Division of Biosafety Evaluation and Control, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea
| | - Won Kim
- Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea
| | - Seung-Hak Cho
- Division of Enteric Diseases, Center for Infectious Diseases, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea
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Kwon T, Bak YS, Jung YH, Yu YB, Choi JT, Kim CH, Kim JB, Kim W, Cho SH. Whole-genome sequencing and comparative genomic analysis of Escherichia coli O91 strains isolated from symptomatic and asymptomatic human carriers. Gut Pathog 2016; 8:57. [PMID: 27891181 PMCID: PMC5106847 DOI: 10.1186/s13099-016-0138-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/01/2016] [Indexed: 01/05/2023] Open
Abstract
Background The Shiga toxin–producing Escherichia coli (STEC) O91:H21 strains NCCP15736 and NCCP15737 were isolated during a single outbreak in Korea, NCCP15736 from a symptomatic carrier and NCCP15737 from an asymptomatic carrier. To investigate genomic differences between the two strains, we performed whole-genome sequencing of both strains and conducted a comparative genomic analysis. Results Using the Illumina HiSeq 2000 platform and Rapid Annotation using the Subsystem Technology (RAST) server, whole-genome sequences of NCCP15736 and NCCP15737 were obtained and annotated. Phylogenetic analysis of ten E. coli strains showed that NCCP15736 and NCCP15737 are evolutionarily close. The two strains were found to be most close to E. coli O91:NM str. 2009C-3745. The genomic comparison showed that the fimD gene of NCCP15737 is truncated and that the truncation could underlie the defects in infection and pathogenicity of NCCP15737. The two strains showed the same virulence factor profiles, and we identified 25 virulence factors from NCCP15736 and NCCP15737, respectively. We identified ten and nine phage-associated regions in the NCCP15736 and NCCP15737 genomes, respectively; the two strains share five of these. Conclusions NCCP15736 and NCCP15737 differ at the genomic level, even though they share features such as virulence-related genes. NCCP15737 has a deletion in fimD, which may underlie its asymptomatic character. We conclude that complete genome sequencing and integration of other types of omics data are needed to fully reveal the mechanism underlying the asymptomatic character of NCCP15737. Electronic supplementary material The online version of this article (doi:10.1186/s13099-016-0138-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Taesoo Kwon
- Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea
| | - Young-Seok Bak
- Department of Emergency Medical Service, Sun Moon University, Asan-si, Chungcheongnam-do, 31460 Republic of Korea
| | - Young-Hee Jung
- Division of Antimicrobial Resistance, Center for Infectious Diseases, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea
| | - Young-Bin Yu
- Department of Biomedical Laboratory Science, College of Medical Science, Konyang University, Daejeon, 302-832 Republic of Korea
| | - Jong Tae Choi
- Department of Biomedical Laboratory Science, Kyungdong University, 815 Gyeonhwon-ro, Munmak-eup, Wonju-si, Gangwon-do 26495 Republic of Korea
| | - Cheorl-Ho Kim
- Glycobiology Unit, Department of Biological Science, Sungkyunkwan University and Samsung Advanced Institute for Health Sciences and Technology (SAIHST), 2066 Seobu-ro, Suwon, 16419 Republic of Korea
| | - Jung-Beom Kim
- Department of Food Science and Technology, Sunchon National University, Sunchon, Jeonnam 540-950 Republic of Korea
| | - Won Kim
- Interdisciplinary Program in Bioinformatics, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 Republic of Korea
| | - Seung-Hak Cho
- Division of Enteric Diseases, Center for Infectious Diseases, Korea National Institute of Health, Cheongju, 363-951 Republic of Korea
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Ailte I, Lingelem ABD, Kavaliauskiene S, Bergan J, Kvalvaag AS, Myrann AG, Skotland T, Sandvig K. Addition of lysophospholipids with large head groups to cells inhibits Shiga toxin binding. Sci Rep 2016; 6:30336. [PMID: 27458147 PMCID: PMC4960542 DOI: 10.1038/srep30336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/30/2016] [Indexed: 12/20/2022] Open
Abstract
Shiga toxin (Stx), an AB5 toxin, binds specifically to the neutral glycosphingolipid Gb3 at the cell surface before being transported into cells. We here demonstrate that addition of conical lysophospholipids (LPLs) with large head groups inhibit Stx binding to cells whereas LPLs with small head groups do not. Lysophosphatidylinositol (LPI 18:0), the most efficient LPL with the largest head group, was selected for in-depth investigations to study how the binding of Stx is regulated. We show that the inhibition of Stx binding by LPI is reversible and possibly regulated by cholesterol since addition of methyl-β-cyclodextrin (mβCD) reversed the ability of LPI to inhibit binding. LPI-induced inhibition of Stx binding is independent of signalling and membrane turnover as it occurs in fixed cells as well as after depletion of cellular ATP. Furthermore, data obtained with fluorescent membrane dyes suggest that LPI treatment has a direct effect on plasma membrane lipid packing with shift towards a liquid disordered phase in the outer leaflet, while lysophosphoethanolamine (LPE), which has a small head group, does not. In conclusion, our data show that cellular treatment with conical LPLs with large head groups changes intrinsic properties of the plasma membrane and modulates Stx binding to Gb3.
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Affiliation(s)
- Ieva Ailte
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anne Berit Dyve Lingelem
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Simona Kavaliauskiene
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Research and Innovation, Østfold Hospital, Sarpsborg, Norway
| | - Audun Sverre Kvalvaag
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Anne-Grethe Myrann
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Tore Skotland
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Kirsten Sandvig
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
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Inactivation and potential reactivation of pathogenic Escherichia coli O157:H7 in bovine milk exposed to three monochromatic ultraviolet UVC lights. Food Microbiol 2015; 49:74-81. [DOI: 10.1016/j.fm.2015.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 01/06/2015] [Accepted: 01/31/2015] [Indexed: 02/07/2023]
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Distribution of Shiga toxin genes subtypes in B1 phylotypes of Escherichia coli isolated from calves suffering from diarrhea in Tehran suburb using DNA oligonucleotide arrays. IRANIAN JOURNAL OF MICROBIOLOGY 2015; 7:191-7. [PMID: 26697157 PMCID: PMC4685162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND OBJECTIVES Shiga toxin-producing Escherichia coli (STEC) have emerged as human pathogens and contamination via animal origin has been a major public health concern. We compared the distribution of phylogenetic groups and prevalence of stx gene variants among the pathogenic strains of Escherichia coli isolated from feces of diarrheatic calves in Tehran suburb farms. MATERIALS AND METHODS In this study we screened 140 diarrheatic calves (1-15 days old) for E. coli strains during a 3 months period of time. The isolated strains were grouped into different phylotypes according to the presence of chuA, yjaA and TSPE4.C2 genes. Then, the prevalence of stx gene subtypes was evaluated in the B1 phylotypes. RESULTS From diarrheatic calves, 51 bacterial isolates were biochemically identified as E. coli and 31 isolates out of 51 were considered B1 phylotype using DNA Microarray technology. Of these isolates, 20 contained stx1a and stx1b and one harbored all mentioned variants of stx genes except stx2b2 . CONCLUSION This study showed that in Tehran suburb, the B1 phylotype of E. coli is prevalent as a causative agent of diarrhea in calves and the prevalence of stx1 gene subtypes is dominant in comparison with other subtypes. Considering the possibility that these stx genes can be spread to other strains, bovine E. coli strains are an important source of stx genes for other strains and further study and surveillance seems to be required for the exact identification of virulence profile of E. coli phylotypes in different hosts.
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Kwak MJ, Kwon SK, Cho SH, Kim JF. Genome sequences of the Shiga-like toxin-producing Escherichia coli NCCP15655 and NCCP15656. Gut Pathog 2015; 7:13. [PMID: 25991925 PMCID: PMC4436796 DOI: 10.1186/s13099-015-0060-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/23/2015] [Indexed: 12/16/2022] Open
Abstract
Background Virulence genes can spread among commensal bacteria through horizontal gene transfer. The bacterium with novel virulence factors may pose a severe threat to public health because of the absence of a management system unlike known pathogens. Especially, when a pathogenic bacterium acquires a new kind of virulence genes, it tends to exhibit stronger virulence. In this study, we analyzed the genomes of the two strains of Escherichia coli that were isolated from the feces of patients with diarrhea and produce Shiga-like toxin. Results Phylogenetic analysis of conserved genes and average nucleotide identity values of the draft genome sequences indicate that strains NCCP15655 and NCCP15656, isolated from diarrhea patients, belong to the B1 group of E. coli and form a sister clade with strain E24377A. However, the proportion the genes belonging to the subsystem category “phages, prophages, transposable elements, plasmids” and “virulence, disease and defense” are higher than E24377A. Indeed, in their genomes, genes encoding Shiga toxin type 1, Shiga toxin type 2, and type 1 fimbriae were detected. Moreover, a plasmid encoding hemolysin and entropathogenic E. coli secreted protein C was identified in both genomes. Conclusions Through the genome analysis of NCCP15655 and NCCP15656, we identified two types of Shiga-like toxin genes that could be responsible for the manifestation of the diarrhea symptom. However, the LEE island, which is one of the major virulence factors of enterohemorrhagic E. coli, was not detected and they are most similar with non-Shiga-like toxin-producing E. coli at the genomic level. NCCP15655 and NCCP15656 will be good examples of Shiga-like toxin-producing E. coli whose genomes are not as similar with typical enterohemorrhagic E. coli as non-Shiga-like toxin-producing E. coli.
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Affiliation(s)
- Min-Jung Kwak
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea ; Biosystems and Bioengineering Program, University of Science and Technology, 217 Gajung-ro, Yuseong-gu, Daejeon, 305-350, Republic of Korea
| | - Soon-Kyeong Kwon
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea
| | - Seung-Hak Cho
- Division of Enteric Diseases, Center for Infectious Diseases, Korea National Institute of Health, Heungdeok-Gu, Cheongju, 363-951 Republic of Korea
| | - Jihyun F Kim
- Department of Systems Biology and Division of Life Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Republic of Korea
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12
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Ashton PM, Perry N, Ellis R, Petrovska L, Wain J, Grant KA, Jenkins C, Dallman TJ. Insight into Shiga toxin genes encoded by Escherichia coli O157 from whole genome sequencing. PeerJ 2015; 3:e739. [PMID: 25737808 PMCID: PMC4338798 DOI: 10.7717/peerj.739] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/05/2015] [Indexed: 11/20/2022] Open
Abstract
The ability of Shiga toxin-producing Escherichia coli (STEC) to cause severe illness in humans is determined by multiple host factors and bacterial characteristics, including Shiga toxin (Stx) subtype. Given the link between Stx2a subtype and disease severity, we sought to identify the stx subtypes present in whole genome sequences (WGS) of 444 isolates of STEC O157. Difficulties in assembling the stx genes in some strains were overcome by using two complementary bioinformatics methods: mapping and de novo assembly. We compared the WGS analysis with the results obtained using a PCR approach and investigated the diversity within and between the subtypes. All strains of STEC O157 in this study had stx1a, stx2a or stx2c or a combination of these three genes. There was over 99% (442/444) concordance between PCR and WGS. When common source strains were excluded, 236/349 strains of STEC O157 had multiple copies of different Stx subtypes and 54 had multiple copies of the same Stx subtype. Of those strains harbouring multiple copies of the same Stx subtype, 33 had variants between the alleles while 21 had identical copies. Strains harbouring Stx2a only were most commonly found to have multiple alleles of the same subtype (42%). Both the PCR and WGS approach to stx subtyping provided a good level of sensitivity and specificity. In addition, the WGS data also showed there were a significant proportion of strains harbouring multiple alleles of the same Stx subtype associated with clinical disease in England.
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Affiliation(s)
- Philip M Ashton
- Gastrointestinal Bacteria Reference Unit, Public Health England , London , UK
| | - Neil Perry
- Gastrointestinal Bacteria Reference Unit, Public Health England , London , UK
| | - Richard Ellis
- Animal & Plant Health Agency , New Haw, Addlestone, Surrey , UK
| | | | - John Wain
- University of East Anglia , Norwich Research Park, Norwich , UK
| | - Kathie A Grant
- Gastrointestinal Bacteria Reference Unit, Public Health England , London , UK
| | - Claire Jenkins
- Gastrointestinal Bacteria Reference Unit, Public Health England , London , UK
| | - Tim J Dallman
- Gastrointestinal Bacteria Reference Unit, Public Health England , London , UK
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13
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Delannoy S, Mariani-Kurkdjian P, Bonacorsi S, Liguori S, Fach P. Characteristics of emerging human-pathogenic Escherichia coli O26:H11 strains isolated in France between 2010 and 2013 and carrying the stx2d gene only. J Clin Microbiol 2015; 53:486-92. [PMID: 25428148 PMCID: PMC4298503 DOI: 10.1128/jcm.02290-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/17/2014] [Indexed: 02/07/2023] Open
Abstract
Strains of Escherichia coli O26:H11 that were positive for stx2 alone (n = 23), which were not epidemiologically related or part of an outbreak, were isolated from pediatric patients in France between 2010 and 2013. We were interested in comparing these strains with the new highly virulent stx2a-positive E. coli O26 clone sequence type 29 (ST29) that has emerged recently in Europe, and we tested them by multilocus sequence typing (MLST), stx2 subtyping, clustered regularly interspaced short palindromic repeat (CRISPR) sequencing, and plasmid (ehxA, katP, espP, and etpD) and chromosomal (Z2098, espK, and espV) virulence gene profiling. We showed that 16 of the 23 strains appeared to correspond to this new clone, but the characteristics of 12 strains differed significantly from the previously described characteristics, with negative results for both plasmid and chromosomal genetic markers. These 12 strains exhibited a ST29 genotype and related CRISPR arrays (CRISPR2a alleles 67 or 71), suggesting that they evolved in a common environment. This finding was corroborated by the presence of stx2d in 7 of the 12 ST29 strains. This is the first time that E. coli O26:H11 carrying stx2d has been isolated from humans. This is additional evidence of the continuing evolution of virulent Shiga toxin-producing E. coli (STEC) O26 strains. A new O26:H11 CRISPR PCR assay, SP_O26_E, has been developed for detection of these 12 particular ST29 strains of E. coli O26:H11. This test is useful to better characterize the stx2-positive O26:H11 clinical isolates, which are associated with severe clinical outcomes such as bloody diarrhea and hemolytic uremic syndrome.
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Affiliation(s)
- Sabine Delannoy
- French Agency for Food, Environmental, and Occupational Health and Safety, Food Safety Laboratory, Platform IdentyPath, Maisons-Alfort, France
| | - Patricia Mariani-Kurkdjian
- AP-HP, Hôpital Robert-Debré, Service de Microbiologie, CNR Associé Escherichia coli, Paris, France IAME, UMR 1137, INSERM, Paris, France IAME, UMR 1137, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Stephane Bonacorsi
- AP-HP, Hôpital Robert-Debré, Service de Microbiologie, CNR Associé Escherichia coli, Paris, France IAME, UMR 1137, INSERM, Paris, France IAME, UMR 1137, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Sandrine Liguori
- AP-HP, Hôpital Robert-Debré, Service de Microbiologie, CNR Associé Escherichia coli, Paris, France Institut de Veille Sanitaire, Saint Maurice, France
| | - Patrick Fach
- French Agency for Food, Environmental, and Occupational Health and Safety, Food Safety Laboratory, Platform IdentyPath, Maisons-Alfort, France
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14
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Characterization and application of phages isolated from sewage for reduction of Escherichia coli O157:H7 in biofilm. Lebensm Wiss Technol 2015. [DOI: 10.1016/j.lwt.2014.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Eppinger M, Cebula TA. Future perspectives, applications and challenges of genomic epidemiology studies for food-borne pathogens: A case study of Enterohemorrhagic Escherichia coli (EHEC) of the O157:H7 serotype. Gut Microbes 2014; 6:194-201. [PMID: 25483335 PMCID: PMC4615391 DOI: 10.4161/19490976.2014.969979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The shiga-toxin (Stx)-producing human pathogen Escherichia coli serotype O157:H7 is a highly pathogenic subgroup of Stx-producing E. coli (STEC) with food-borne etiology and bovine reservoir. Each year in the U. S., approximately 100,000 patients are infected with enterohemorrhagic E. coli (EHEC) of the O157:H7 serotype. This food-borne pathogen is a global public health threat responsible for widespread outbreaks of human disease. Since its initial discovery in 1982, O157:H7 has rapidly become the dominant EHEC serotype in North America. Hospitalization rates among patients as high as 50% have been reported for severe outbreaks of human disease. Symptoms of disease can rapidly deteriorate and progress to life-threatening complications such as Hemolytic Uremic Syndrome (HUS), the leading cause of kidney failure in children, or Hemorrhagic Colitis. In depth understanding of the genomic diversity that exists among currently circulating EHEC populations has broad applications for improved molecular-guided biosurveillance, outbreak preparedness, diagnostic risk assessment, and development of alternative toxin-suppressing therapeutics.
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Affiliation(s)
- Mark Eppinger
- Department of Biology; The University of Texas at San Antonio; San Antonio, TX, USA,South Texas Center For Emerging Infectious Diseases; The University of Texas at San Antonio; San Antonio, TX, USA,Correspondence to: Mark Eppinger;
| | - Thomas A Cebula
- Department of Biology; Johns Hopkins University; Baltimore, MD, USA,CosmosID; Fairfax, VA, USA
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16
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Abstract
ABSTRACT
To help assess the clinical and public health risks associated with different Shiga toxin-producing
Escherichia coli
(STEC) strains, an empirical classification scheme was used to classify STEC into five “seropathotypes” (seropathotype A [high risk] to seropathotypes D and E [minimal risk]). This definition is of considerable value in cases of human infection but is also problematic because not all STEC infections are fully characterized and coupled to reliable clinical information. Outbreaks with emerging hybrid strains continuously challenge our understanding of virulence potential and may result in incorrect classification of specific pathotypes; an example is the hybrid strain that caused the 2011 outbreak in Germany, STEC/EAggEC O104:H4, which may deserve an alternative seropathotype designation. The integration of mobile virulence factors in the stepwise and parallel evolution of pathogenic lineages of STEC collides with the requirements of a good taxonomy, which separates elements of each group into subgroups that are mutually exclusive, unambiguous, and, together, include all possibilities. The concept of (sero)-pathotypes is therefore challenged, and the need to identify factors of STEC that absolutely predict the potential to cause human disease is obvious. Because the definition of hemolytic-uremic syndrome (HUS) is distinct, a basic and primary definition of HUS-associated
E. coli
(HUSEC) for first-line public health action is proposed:
stx2
in a background of an
eae-
or
aggR
-positive
E. coli
followed by a second-line subtyping of
stx
genes that refines the definition of HUSEC to include only
stx2a
and
stx2d
. All other STEC strains are considered “low-risk” STEC.
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17
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Silva CJ, Erickson-Beltran ML, Skinner CB, Dynin I, Hui C, Patfield SA, Carter JM, He X. Safe and Effective Means of Detecting and Quantitating Shiga-Like Toxins in Attomole Amounts. Anal Chem 2014; 86:4698-706. [DOI: 10.1021/ac402930r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Christopher J. Silva
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Melissa L. Erickson-Beltran
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Craig B. Skinner
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Irina Dynin
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Colleen Hui
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Stephanie A. Patfield
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - John Mark Carter
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
| | - Xiaohua He
- Western Regional Research Center, United States Department of Agriculture, Albany, California 94710, United States
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18
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Murinda SE, Ibekwe AM, Zulkaffly S, Cruz A, Park S, Razak N, Paudzai FM, Ab Samad L, Baquir K, Muthaiyah K, Santiago B, Rusli A, Balkcom S. Real-time isothermal detection of Shiga toxin-producing Escherichia coli using recombinase polymerase amplification. Foodborne Pathog Dis 2014; 11:529-36. [PMID: 24749488 DOI: 10.1089/fpd.2013.1663] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are a major family of foodborne pathogens of public health, zoonotic, and economic significance in the United States and worldwide. To date, there are no published reports on use of recombinase polymerase amplification (RPA) for STEC detection. The primary goal of this study was to assess the potential application of RPA in detection of STEC. This study focused on designing and evaluating RPA primers and fluorescent probes for isothermal (39°C) detection of STEC. Compatible sets of candidate primers and probes were designed for detection of Shiga toxin 1 and 2 (Stx1 and 2), respectively. The sets were evaluated for specificity and sensitivity against STEC (n=12) of various stx genotypes (stx1/stx2, stx1, or stx2, respectively), including non-Stx-producing E. coli (n=28) and other genera (n=7). The primers and probes that were designed targeted amplification of the subunit A moiety of stx1 and stx2. The assay detected STEC in real time (within 5-10 min at 39°C) with high sensitivity (93.5% vs. 90%; stx1 vs. stx2), specificity (99.1% vs. 100%; stx1 vs. stx2), and predictive value (97.9% for both stx1 vs. stx2). Limits of detection of ∼ 5-50 colony-forming units/mL were achieved in serially diluted cultures grown in brain heart infusion broth. This study successfully demonstrated for the first time that RPA can be used for isothermal real-time detection of STEC.
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Affiliation(s)
- Shelton E Murinda
- 1 Animal and Veterinary Sciences Department, Center for Antimicrobial Research and Food Safety, California State Polytechnic University , Pomona, California
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19
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Genome Sequence of Escherichia coli O157:H7 Strain 2886-75, Associated with the First Reported Case of Human Infection in the United States. GENOME ANNOUNCEMENTS 2014; 2:2/1/e01120-13. [PMID: 24407635 PMCID: PMC3886948 DOI: 10.1128/genomea.01120-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
First identified in 1982 as a human pathogen, enterohemorrhagic Escherichia coli of the O157:H7 serotype is a major cause of food-borne acquired human infections. Here, we report the genome sequence of the first known strain of this serotype isolated in the United States.
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20
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Lee YD, Kim JY, Park JH. Characteristics of coliphage ECP4 and potential use as a sanitizing agent for biocontrol of Escherichia coli O157:H7. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.04.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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21
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Multicenter evaluation of a sequence-based protocol for subtyping Shiga toxins and standardizing Stx nomenclature. J Clin Microbiol 2012; 50:2951-63. [PMID: 22760050 DOI: 10.1128/jcm.00860-12] [Citation(s) in RCA: 583] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When Shiga toxin-producing Escherichia coli (STEC) strains emerged as agents of human disease, two types of toxin were identified: Shiga toxin type 1 (Stx1) (almost identical to Shiga toxin produced by Shigella dysenteriae type 1) and the immunologically distinct type 2 (Stx2). Subsequently, numerous STEC strains have been characterized that express toxins with variations in amino acid sequence, some of which confer unique biological properties. These variants were grouped within the Stx1 or Stx2 type and often assigned names to indicate that they were not identical in sequence or phenotype to the main Stx1 or Stx2 type. A lack of specificity or consistency in toxin nomenclature has led to much confusion in the characterization of STEC strains. Because serious outcomes of infection have been attributed to certain Stx subtypes and less so with others, we sought to better define the toxin subtypes within the main Stx1 and Stx2 types. We compared the levels of relatedness of 285 valid sequence variants of Stx1 and Stx2 and identified common sequences characteristic of each of three Stx/Stx1 and seven Stx2 subtypes. A novel, simple PCR subtyping method was developed, independently tested on a battery of 48 prototypic STEC strains, and improved at six clinical and research centers to test the reproducibility, sensitivity, and specificity of the PCR. Using a consistent schema for nomenclature of the Stx toxins and stx genes by phylogenetic sequence-based relatedness of the holotoxin proteins, we developed a typing approach that should obviate the need to bioassay each newly described toxin and that predicts important biological characteristics.
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22
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Towards a pathogenic Escherichia coli detection platform using multiplex SYBR®Green Real-time PCR methods and high resolution melting analysis. PLoS One 2012; 7:e39287. [PMID: 22761753 PMCID: PMC3382608 DOI: 10.1371/journal.pone.0039287] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 05/17/2012] [Indexed: 12/01/2022] Open
Abstract
Escherichia coli is a group of bacteria which has raised a lot of safety concerns in recent years. Five major intestinal pathogenic groups have been recognized amongst which the verocytotoxin or shiga-toxin (stx1 and/or stx2) producing E. coli (VTEC or STEC respectively) have received a lot of attention recently. Indeed, due to the high number of outbreaks related to VTEC strains, the European Food Safety Authority (EFSA) has requested the monitoring of the “top-five” serogroups (O26, O103, O111, O145 and O157) most often encountered in food borne diseases and addressed the need for validated VTEC detection methods. Here we report the development of a set of intercalating dye Real-time PCR methods capable of rapidly detecting the presence of the toxin genes together with intimin (eae) in the case of VTEC, or aggregative protein (aggR), in the case of the O104:H4 strain responsible for the outbreak in Germany in 2011. All reactions were optimized to perform at the same annealing temperature permitting the multiplex application in order to minimize the need of material and to allow for high-throughput analysis. In addition, High Resolution Melting (HRM) analysis allowing the discrimination among strains possessing similar virulence traits was established. The development, application to food samples and the flexibility in use of the methods are thoroughly discussed. Together, these Real-time PCR methods facilitate the detection of VTEC in a new highly efficient way and could represent the basis for developing a simple pathogenic E. coli platform.
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23
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Ilić K, Jakovljević E, Skodrić-Trifunović V. Social-economic factors and irrational antibiotic use as reasons for antibiotic resistance of bacteria causing common childhood infections in primary healthcare. Eur J Pediatr 2012; 171:767-77. [PMID: 21987082 DOI: 10.1007/s00431-011-1592-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/21/2011] [Indexed: 11/28/2022]
Abstract
The most prevalent childhood bacterial infections in primary healthcare are respiratory, gastrointestinal and urogenital infections. The main aim of this paper was to consider factors (socio-economic factors and irrational antibiotic use) that contribute to the development of bacterial resistance, as well as measures that resulted in a reduction of this problem. Computerized search through the Medline of published articles on antibiotic resistance from 1996 to 2011 in English or Serbian was completed in August 2011. Combinations of used terms were antimicrobial/antibacterial/antibiotic and resistance/susceptibility in pediatric/children, and Streptococcus pneumoniae/Streptococci/Haemophilus influenzae/Salmonellae/Escherichia coli/Shigella/Staphylococcus aureus as well as antibiotics/antimicrobials/antibacterials and consumption/utilization/use. In many developing countries, antibiotic dispensing and its use in medicine, cattle breeding and agriculture are inadequately regulated, or existing laws are not being appropriately implemented. In addition, human travel contributes to antimicrobial drug resistance around the world. All of these factors have led to a very high level of bacterial resistance. On the contrary, in countries with a clearly defined and implemented legal framework concerning antibiotic prescribing, dispensing and utilization, the use of antibiotics is under constant surveillance. That resulted in a significantly lower antibacterial resistance. In conclusion, bacterial resistance could be reduced by the implementation of systemic and long-term measures at a country level as well as at all levels of healthcare. In order to reduce bacterial resistance, antibiotic use needs to be precisely regulated, and regulations should be coherent with practice. The international community must have a more active role in solving this global problem.
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Affiliation(s)
- Katarina Ilić
- Department of Pharmacology, School of Pharmacy, University of Belgrade, PO BOX 146, Vojvode Stepe 450, 11221, Belgrade, Republic of Serbia.
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24
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Alperi A, Figueras MJ. Human isolates of Aeromonas possess Shiga toxin genes (stx1 and stx2) highly similar to the most virulent gene variants of Escherichia coli. Clin Microbiol Infect 2011; 16:1563-7. [PMID: 20219084 DOI: 10.1111/j.1469-0691.2010.03203.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Strains producing Shiga toxins, encoded by stx1 and stx2 genes, can cause diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome. PCR screening of 80 clinical Aeromonas strains showed that 19 were stx1-positive and only one was positive for both stx1 and stx2. PCR bands were very faint for some strains and negative results were obtained after subculturing. The obtained sequences of Aeromonas stx1 and stx2 genes were highly similar to those of the most virulent stx gene variants of Shiga toxin-producing Escherichia coli. These results may lead to a better understanding of the potential pathogenicity and virulence mechanisms of Aeromonas.
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Affiliation(s)
- A Alperi
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain
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25
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Abstract
Purified Shiga toxin (Stx) alone is capable of producing systemic complications, including hemolytic-uremic syndrome (HUS), in animal models of disease. Stx includes two major antigenic forms (Stx1 and Stx2), with minor variants of Stx2 (Stx2a to -h). Stx2a is more potent than Stx1. Epidemiologic studies suggest that Stx2 subtypes also differ in potency, but these differences have not been well documented for purified toxin. The relative potencies of five purified Stx2 subtypes, Stx2a, Stx2b, Stx2c, Stx2d, and activated (elastase-cleaved) Stx2d, were studied in vitro by examining protein synthesis inhibition using Vero monkey kidney cells and inhibition of metabolic activity (reduction of resazurin to fluorescent resorufin) using primary human renal proximal tubule epithelial cells (RPTECs). In both RPTECs and Vero cells, Stx2a, Stx2d, and elastase-cleaved Stx2d were at least 25 times more potent than Stx2b and Stx2c. In vivo potency in mice was also assessed. Stx2b and Stx2c had potencies similar to that of Stx1, while Stx2a, Stx2d, and elastase-cleaved Stx2d were 40 to 400 times more potent than Stx1.
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26
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Conrady DG, Flagler MJ, Friedmann DR, Vander Wielen BD, Kovall RA, Weiss AA, Herr AB. Molecular basis of differential B-pentamer stability of Shiga toxins 1 and 2. PLoS One 2010; 5:e15153. [PMID: 21203383 PMCID: PMC3010993 DOI: 10.1371/journal.pone.0015153] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 10/25/2010] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli strain O157:H7 is a major cause of food poisoning that can result in severe diarrhea and, in some cases, renal failure. The pathogenesis of E. coli O157:H7 is in large part due to the production of Shiga toxin (Stx), an AB(5) toxin that consists of a ribosomal RNA-cleaving A-subunit surrounded by a pentamer of receptor-binding B subunits. There are two major isoforms, Stx1 and Stx2, which differ dramatically in potency despite having 57% sequence identity. Animal studies and epidemiological studies show Stx2 is associated with more severe disease. Although the molecular basis of this difference is unknown, data suggest it is associated with the B-subunit. Mass spectrometry studies have suggested differential B-pentamer stability between Stx1 and Stx2. We have examined the relative stability of the B-pentamers in solution. Analytical ultracentrifugation using purified B-subunits demonstrates that Stx2B, the more deadly isoform, shows decreased pentamer stability compared to Stx1B (EC(50) = 2.3 µM vs. EC(50) = 0.043 µM for Stx1B). X-ray crystal structures of Stx1B and Stx2B identified a glutamine in Stx2 (versus leucine in Stx1) within the otherwise strongly hydrophobic interface between B-subunits. Interchanging these residues switches the stability phenotype of the B-pentamers of Stx1 and Stx2, as demonstrated by analytical ultracentrifugation and circular dichroism. These studies demonstrate a profound difference in stability of the B-pentamers in Stx1 and Stx2, illustrate the mechanistic basis for this differential stability, and provide novel reagents to test the basis for differential pathogenicity of these toxins.
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Affiliation(s)
- Deborah G. Conrady
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Michael J. Flagler
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - David R. Friedmann
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Bradley D. Vander Wielen
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Rhett A. Kovall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (RAK); (AAW); (ABH)
| | - Alison A. Weiss
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (RAK); (AAW); (ABH)
| | - Andrew B. Herr
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (RAK); (AAW); (ABH)
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27
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Parker JL, Shaw JG. Aeromonas spp. clinical microbiology and disease. J Infect 2010; 62:109-18. [PMID: 21163298 DOI: 10.1016/j.jinf.2010.12.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 01/14/2023]
Abstract
Members of the genus Aeromonas inhabit various aquatic environments and are responsible for, and are implicated in, a number of intestinal and extra-intestinal infections in humans as well as other animals. This review focuses on invasive human infection and disease and summarizes available findings regarding the microbiology and detection of Aeromonas spp., with emphasis on successful identification and diagnosis, and the control of disease in the population. Antimicrobial resistance and therapy of Aeromonas spp. is also discussed.
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Affiliation(s)
- Jennifer L Parker
- Academic Unit of Immunology and Infectious Diseases, Department of Infection and Immunity, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
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28
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Shiga toxin B subunits induce VWF secretion by human endothelial cells and thrombotic microangiopathy in ADAMTS13-deficient mice. Blood 2010; 116:3653-9. [PMID: 20644116 DOI: 10.1182/blood-2010-02-271957] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diarrhea-associated hemolytic uremic syndrome (D+HUS) is the most common cause of acute renal failure among children. Renal damage in D+HUS is caused by Shiga toxin (Stx), which is elaborated by Shigella dysenteriae and certain strains of Escherichia coli, in North America principally E coli O157:H7. Recent studies demonstrate that Stx also induces von Willebrand factor (VWF) secretion by human endothelial cells and causes thrombotic thrombocytopenic purpura, a disease with similarities to D+HUS, in Adamts13(-/-) mice. Stx occurs in 2 variants, Stx1 and Stx2, each of which is composed of 1 catalytically active A subunit that is responsible for cytotoxicity, and 5 identical B subunits that mediate binding to cell-surface globo-triaosylceramide. We now report that B subunits from Stx1 or Stx2 can stimulate the acute secretion of VWF in the absence of the cytotoxic A subunit. This rapid effect requires binding and clustering of globotriaosylceramide, and depends on plasma membrane cholesterol and caveolin-1 but not clathrin. Furthermore, similar to Stx2 holotoxin, the isolated Stx2B subunits induce thrombotic microangiopathy in Adamts13(-/-) mice. These results demonstrate the existence of a novel Stx B-induced lipid raft-dependent signaling pathway in endothelial cells that may be responsible for some of the biological effects attributed previously to the cytotoxic Stx A subunit.
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29
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Presence and characterization of shiga toxin-producing Escherichia coli and other potentially diarrheagenic E. coli strains in retail meats. Appl Environ Microbiol 2010; 76:1709-17. [PMID: 20080990 DOI: 10.1128/aem.01968-09] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To determine the presence of Shiga toxin-producing Escherichia coli (STEC) and other potentially diarrheagenic E. coli strains in retail meats, 7,258 E. coli isolates collected by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) retail meat program from 2002 to 2007 were screened for Shiga toxin genes. In addition, 1,275 of the E. coli isolates recovered in 2006 were examined for virulence genes specific for other diarrheagenic E. coli strains. Seventeen isolates (16 from ground beef and 1 from a pork chop) were positive for stx genes, including 5 positive for both stx(1) and stx(2), 2 positive for stx(1), and 10 positive for stx(2). The 17 STEC strains belonged to 10 serotypes: O83:H8, O8:H16, O15:H16, O15:H17, O88:H38, ONT:H51, ONT:H2, ONT:H10, ONT:H7, and ONT:H46. None of the STEC isolates contained eae, whereas seven carried enterohemorrhagic E. coli (EHEC) hlyA. All except one STEC isolate exhibited toxic effects on Vero cells. DNA sequence analysis showed that the stx(2) genes from five STEC isolates encoded mucus-activatable Stx2d. Subtyping of the 17 STEC isolates by pulsed-field gel electrophoresis (PFGE) yielded 14 distinct restriction patterns. Among the 1,275 isolates from 2006, 11 atypical enteropathogenic E. coli (EPEC) isolates were identified in addition to 3 STEC isolates. This study demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains. The presence of atypical EPEC strains in retail meat is also of concern due to their potential to cause human infections.
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Shiga toxins, and the genes encoding them, in fecal samples from native Idaho ungulates. Appl Environ Microbiol 2008; 75:862-5. [PMID: 19060170 DOI: 10.1128/aem.01158-08] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cattle are a known reservoir of Shiga toxin-producing Escherichia coli. The prevalence and stability of Shiga toxin and/or Shiga toxin genes among native wild ungulates in Idaho were investigated. The frequency of both Shiga genes and toxin was similar to that reported for Idaho cattle ( approximately 19%).
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