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Wang X, Yu D, Chui L, Zhou T, Feng Y, Cao Y, Zhi S. A Comprehensive Review on Shiga Toxin Subtypes and Their Niche-Related Distribution Characteristics in Shiga-Toxin-Producing E. coli and Other Bacterial Hosts. Microorganisms 2024; 12:687. [PMID: 38674631 PMCID: PMC11052178 DOI: 10.3390/microorganisms12040687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Shiga toxin (Stx), the main virulence factor of Shiga-toxin-producing E. coli (STEC), was first discovered in Shigella dysenteriae strains. While several other bacterial species have since been reported to produce Stx, STEC poses the most significant risk to human health due to its widespread prevalence across various animal hosts that have close contact with human populations. Based on its biochemical and molecular characteristics, Shiga toxin can be grouped into two types, Stx1 and Stx2, among which a variety of variants and subtypes have been identified in various bacteria and host species. Interestingly, the different Stx subtypes appear to vary in their host distribution characteristics and in the severity of diseases that they are associated with. As such, this review provides a comprehensive overview on the bacterial species that have been recorded to possess stx genes to date, with a specific focus on the various Stx subtype variants discovered in STEC, their prevalence in certain host species, and their disease-related characteristics. This review provides a better understanding of the Stx subtypes and highlights the need for rapid and accurate approaches to toxin subtyping for the proper evaluation of the health risks associated with Shiga-toxin-related bacterial food contamination and human infections.
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Affiliation(s)
- Xuan Wang
- School of Public Health, Ningbo University, Ningbo 315000, China; (X.W.); (T.Z.); (Y.F.)
| | - Daniel Yu
- School of Public Health, Univeristy of Alberta, Edmonton, AB T6G 2R3, Canada;
| | - Linda Chui
- Alberta Precision Laboratories-ProvLab, Edmonton, AB T6G 2J2, Canada;
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2B7, Canada
| | - Tiantian Zhou
- School of Public Health, Ningbo University, Ningbo 315000, China; (X.W.); (T.Z.); (Y.F.)
| | - Yu Feng
- School of Public Health, Ningbo University, Ningbo 315000, China; (X.W.); (T.Z.); (Y.F.)
| | - Yuhao Cao
- School of Basic Medical Sciences, Ningbo University, Ningbo 315000, China;
| | - Shuai Zhi
- School of Public Health, Ningbo University, Ningbo 315000, China; (X.W.); (T.Z.); (Y.F.)
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Sadeghi H, Rashedi H, Mazaheri Assadi M, Seyedin Ardebili M. Potential application of bioemulsifier RAG-1 as an anti-staling agent in flat bread quality. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2023; 60:2619-2627. [PMID: 37599842 PMCID: PMC10439091 DOI: 10.1007/s13197-023-05784-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 05/17/2023] [Accepted: 06/01/2023] [Indexed: 08/22/2023]
Abstract
Bread undergoes physicochemical processes known as 'staling', which limits shelf life and quality. Despite the fact that several chemical emulsifiers have been employed to combat this issue, they may offer risks to human health. In this investigation, the effects of bioemulsan, a natural bioemulsifier (BE), on bread quality and staleness were examined. The yield of emulsan generated by Acinetobacter calcoaceticus RAG-1 was 1.49 g/L. The presence of clear zones around colonies, high emulsification value of 100%, and remaining surface tension below 40 mN/m after heating (at 250 °C for 15-20 min) verified emulsan thermal stability. BE-supplemented bread had a greater moisture percentage than the control, resulting in reduced crumb hardening and improved bread quality during storage as measured by moisture content. The first day after adding 0.5% emulsan, the hardness rose from 90.45 N (for the control) to 150.45 N. Texture analysis showed that although the hardness increased during storage, adding emulsan allowed obtaining bread with clearly softer crumb after 2 and 3 days of baking, especially at 0.5% level (from 215.6 N for the control to 150.5 N for 0.5% BE-enriched bread after 2 days, and from 425.7 to 210.25 N after 3 days). Based on the sensory evaluation results, emulsan did not lead to any unpleasant changes on bread organoleptic parameters. Therefore, using bioemulsifier RAG-1 as a green emulsifier and anti-staling agent found to be more promising.
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Affiliation(s)
- Hanieh Sadeghi
- Food Science and Technology, Iranian Association of Official Experts (IAOE), P.O. Box: 3149778838, Tehran, Iran
| | - Hamid Rashedi
- Biotechnology, Chemical Engineering School, College of Engineering, University of Tehran, P.O. Box: 11155-4563, Tehran, Iran
| | - Mahnaz Mazaheri Assadi
- Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran
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Zhong T, Wang Y, Wang X, Freitas-de-Melo A, Li H, Zhan S, Wang L, Cao J, Dai D, Guo J, Li L, Zhang H, Liu J, Niu L. Diarrhea in suckling lambs is associated with changes in gut microbiota, serum immunological and biochemical parameters in an intensive production system. Front Microbiol 2022; 13:1020657. [PMID: 36466638 PMCID: PMC9712182 DOI: 10.3389/fmicb.2022.1020657] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/21/2022] [Indexed: 07/30/2023] Open
Abstract
The incidence of diarrhea in lambs is frequent in large-scale sheep farms, which greatly impacts the growth and health of lambs. The aim of this study was to assess the changes in serum biochemical and immunological parameters and gut microbiome composition in suckling lambs suffering from diarrhea or not, reared on an intensive commercial farm. We found a reduced diversity of intestinal bacteria in suckling lambs suffering from diarrhea. Firmicutes and Bacteroidetes were the dominant flora in both groups of lambs, while the Bacteroidetes decreased in diarrheic lambs, no changes were reported in Firmicutes. Compared with healthy lambs, the proportion of aerobic bacteria, facultative anaerobic bacteria, and stress tolerant bacteria increased in lambs suffering from diarrhea, while that of anaerobic bacteria and potentially pathogenic bacteria decreased slightly. In addition, the contents of total cholesterol, immunoglobulins (Ig) G, and IgM in the serum of lambs suffering from diarrhea were lower than those of healthy lambs. This study explored the association between diarrhea occurrence, intestinal microbial community structure, and metabolic and immunological status in Hu lambs.
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Affiliation(s)
- Tao Zhong
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Yaxuan Wang
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Xinlu Wang
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Aline Freitas-de-Melo
- Departamento de Biociencias Veterinarias, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay
| | - Hua Li
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China
| | - Siyuan Zhan
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Linjie Wang
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jiaxue Cao
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Dinghui Dai
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jiazhong Guo
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Li Li
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Hongping Zhang
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jinwang Liu
- Yulin Sannong Breeding Service Co., Ltd, Yulin, China
| | - Lili Niu
- Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
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Newton K, Gonzalez E, Pitre FE, Brereton NJB. Microbial community origin and fate through a rural wastewater treatment plant. Environ Microbiol 2022; 24:2516-2542. [PMID: 35466495 DOI: 10.1111/1462-2920.16025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/20/2022] [Indexed: 11/29/2022]
Abstract
Conventional wastewater treatment relies on a complex microbiota; however, much of this community is still to be characterised. To better understand the origin, dynamics and fate of bacteria within a wastewater treatment plant: untreated primary wastewater, activated sludge, and post-treatment effluent were characterised. From 3,163 Exact Sequence Variants (ESVs), 860 were annotated to species-level. In primary wastewater, 28% of ESVs were putative bacterial species previously associated with humans, 14% with animals and 5% as common to the environment. Differential abundance analysis revealed significant relative reductions in ESVs from potentially humans-associated species from primary wastewater to activated sludge, and significant increases in ESVs from species associated with nutrient cycling. Between primary wastewater and effluent, 51% of ESVs from human-associated species did not significantly differ, and species such as Bacteroides massiliensis and Bacteroides dorei increased. These findings illustrate that activated sludge increased extracellular protease and urease-producing species, ammonia and nitrite oxidizers, denitrifiers and specific phosphorus accumulators. Although many human-associated species declined, some persisted in effluent, including strains of potential health or environmental concern. Species-level microbial assessment may be useful for understanding variation in wastewater treatment efficiency as well as for monitoring the release of microbes into surface water and the wider ecosystem. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kymberly Newton
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
| | - Emmanuel Gonzalez
- Canadian Center for Computational Genomics, Department of Human Genetics, McGill University, Montréal, H3A 1A4, Canada
| | - Frederic E Pitre
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
| | - Nicholas J B Brereton
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
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Spencer L, Olawuni B, Singh P. Gut Virome: Role and Distribution in Health and Gastrointestinal Diseases. Front Cell Infect Microbiol 2022; 12:836706. [PMID: 35360104 PMCID: PMC8960297 DOI: 10.3389/fcimb.2022.836706] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/10/2022] [Indexed: 12/11/2022] Open
Abstract
The study of the intestinal microbiome is an evolving field of research that includes comprehensive analysis of the vast array of microbes – bacterial, archaeal, fungal, and viral. Various gastrointestinal (GI) diseases, such as Crohn’s disease and ulcerative colitis, have been associated with instability of the gut microbiota. Many studies have focused on importance of bacterial communities with relation to health and disease in humans. The role of viruses, specifically bacteriophages, have recently begin to emerge and have profound impact on the host. Here, we comprehensively review the importance of viruses in GI diseases and summarize their influence in the complex intestinal environment, including their biochemical and genetic activities. We also discuss the distribution of the gut virome as it relates with treatment and immunological advantages. In conclusion, we suggest the need for further studies on this critical component of the intestinal microbiome to decipher the role of the gut virome in human health and disease.
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Mona MH, El-Khodary GM, Abdel-Halim KY, Omran NE, Abd El-Aziz KK, El-Saidy SA. Histopathological alterations induced by marine environmental pollutants on the bivalve Cerastoderma glaucum (Bruguière 1789) from Temsah Lake, Suez Canal, Egypt. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:9971-9989. [PMID: 34510354 DOI: 10.1007/s11356-021-14966-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
Bivalves are considered a main consumed matrix for coastal communities worldwide and classified as hyperaccumulators of pollutants. The present study aims to determine some micro-organisms, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and okadaic acid (OA) levels in Cerastoderma glaucum collected from Temsah Lake, Egypt, and their induction through histopathological damage and caspase-3 protein expression. During the autumn, it was found different types of biological and chemical pollutants, especially benzo[a]pyrene (BaP) that accumulated in C. glaucum soft tissues and exceeded the safety limit for shellfish consumption. Dioxin-like PCB3 was predominant in C. glaucum soft tissues during autumn, but the total levels of PCBs in these tissues have not exceeded the permissible limit. Chlorophyll-a (Chl. a), nutrient concentrations, and Prorocentrum lima dinoflagellates in the water significantly increased during autumn. High P. lima abundance was confirmed by high OA in the soft tissues during this season compared to the other seasons. The measured contaminants may render C. glaucum more susceptible to bacterial and fungal infections. The autumn season showed a significant increase in the colony-forming units (CFU). C. glaucum showed calcification abnormalities and adhering of abnormal brown organic material to the inner surface of the shell valves, which was related to poor water conditions and Vibrio infection. Damages or injuries on gills and digestive gland tissues indicated an impact of the pollutants on C. glaucum. Also, high expressions of caspase-3 were recorded in these tissues during all the seasons. So, C. glaucum cockles, collected from Temsah Lake, may induce serious diseases to consumers, especially when eaten raw or insufficient cooking.
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Affiliation(s)
- Mohamed H Mona
- Department of Zoology, Faculty of Science, Tanta University, Tanta, Egypt
| | - Gihan M El-Khodary
- Department of Zoology, Faculty of Science, Damanhour University, Damanhour, Egypt
| | - Khaled Y Abdel-Halim
- Mammalian & Aquatic Toxicology Department, Central Agriculural Pesticides Laboratory (CAPL), Agricultural Research Center (ARC),12618-Dokki, Giza, Egypt.
| | - Nahla E Omran
- Department of Zoology, Faculty of Science, Tanta University, Tanta, Egypt
| | | | - Salwa A El-Saidy
- Department of Zoology, Faculty of Science, Damanhour University, Damanhour, Egypt
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Sensitive recognition of Shiga toxin using biosensor technology: An efficient platform towards bioanalysis of pathogenic bacterial. Microchem J 2022. [DOI: 10.1016/j.microc.2021.106900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mohaisen MR, McCarthy AJ, Adriaenssens EM, Allison HE. The Site-Specific Recombination System of the Escherichia coli Bacteriophage Φ24 B. Front Microbiol 2020; 11:578056. [PMID: 33162958 PMCID: PMC7581858 DOI: 10.3389/fmicb.2020.578056] [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: 06/30/2020] [Accepted: 09/15/2020] [Indexed: 11/13/2022] Open
Abstract
Stx bacteriophages are members of the lambdoid group of phages and are responsible for Shiga toxin (Stx) production and the dissemination of Shiga toxin genes (stx) across shigatoxigenic Escherichia coli (STEC). These toxigenic bacteriophage hosts can cause life-threatening illnesses, and Stx is the virulence determinant responsible for the severe nature of infection with enterohemorrhagic E. coli, a subset of pathogenic STEC. Stx phages are temperate, and in the present study, the identification of what is actually required for Stx phage Φ24B and bacterial DNA recombination was tested using both in vitro and in situ recombination assays. It is well established that phage λ, which underpins most of what we understand about lambdoid phage biology, requires its own encoded phage attachment site (attP) of 250 bp, a host-encoded attachment site (attB) of 21 bp, and a host-encoded DNA binding protein known as integration host factor (IHF). The assays applied in this study enabled the manipulation of the phage attachment site (attP) and the bacterial attachment site (attB) sequences and the inclusion or exclusion of a host-encoded accessory element known as integration host factor. We were able to demonstrate that the minimal attP sequence required by Φ24B phage is between 350 and 427 bp. Unlike phage λ, the minimal necessary flanking sequences for the attB site do not appear to be equal in size, with a total length between 62 and 93 bp. Furthermore, we identified that the Φ24B integrase does not require IHF to drive the integration and the recombination process. Understanding how this unusual Stx phage integrase works may enable exploitation of its promiscuous nature in the context of genetic engineering.
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Affiliation(s)
- Mohammed Radhi Mohaisen
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.,College of Dentistry, University of Anbar, Ramadi, Iraq
| | - Alan John McCarthy
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | | | - Heather Elizabeth Allison
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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Carvalheira A, Silva J, Teixeira P. Acinetobacter spp. in food and drinking water - A review. Food Microbiol 2020; 95:103675. [PMID: 33397609 DOI: 10.1016/j.fm.2020.103675] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 01/01/2023]
Abstract
Acinetobacter spp. has emerged as a pathogen of major public health concern due to their increased resistance to antibiotics and their association with a wide range of nosocomial infections, community-acquired infections and war and natural disaster-related infections. It is recognized as a ubiquitous organism however, information about the prevalence of different pathogenic species of this genus in food sources and drinking water is scarce. Since the implementation of molecular techniques, the role of foods as a source of several species, including the Acinetobacter baumannii group, has been elucidated. Multidrug resistance was also detected among Acinetobacter spp. isolated from food products. This highlights the importance of foods as potential sources of dissemination of Acinetobacter spp. between the community and clinical environments and reinforces the need for further investigations on the potential health risks of Acinetobacter spp. as foodborne pathogens. The aim of this review was to summarize the published data on the occurrence of Acinetobacter spp. in different food sources and drinking water. This information should be taken into consideration by those responsible for infection control in hospitals and other healthcare facilities.
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Affiliation(s)
- Ana Carvalheira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal
| | - Joana Silva
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal
| | - Paula Teixeira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal.
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Kaur R, Singh D, Kesavan AK, Kaur R. Molecular characterization and antimicrobial susceptibility of bacterial isolates present in tap water of public toilets. Int Health 2020; 12:472-483. [PMID: 31693132 PMCID: PMC7443727 DOI: 10.1093/inthealth/ihz074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The present study was carried out to investigate the tap water quality of public toilets in Amritsar, Punjab, India. METHODS Water samples from the taps of the public toilets were collected in sterile containers and physicochemical and bacteriological analysis was performed using standard methods. Also, genotypic and phenotypic characterization of the bacterial isolates was performed using different biochemical tests and 16S ribosomal RNA analysis. An antibiotic susceptibility test was performed using antibiotics based on their mode of action. A biofilm assay was performed to assess the adhesion potential of the isolates. RESULTS A total of 25 bacterial isolates were identified from the water samples, including Acinetobacter junii, Acinetobacter pittii, Acinetobacter haemolyticus, Bacillus pumilus, Bacillus megaterium, Bacillus marisflavi, Bacillus flexus, Bacillus oceanisediminis, Pseudomonas otitidis, Pseudomonas sp. RR013, Pseudomonas sp. RR021, Pseudomonas sp. RR022, Escherichia coli and Enterobacter cloacae. The results of the antimicrobial susceptibility test revealed that the antibiotics cefodroxil, aztreonam, nitrofurantoin, cefepime, ceftazidime and amoxyclav were found to be mostly ineffective against various isolates. The biofilm assay revealed the weak, moderate and strong biofilm producers among them. CONCLUSIONS The tap water in the public toilets was microbially contaminated and needs to be monitored carefully. The antibiotic susceptibility profile showed that of 25 bacterial isolates, 5 were multidrug resistant. Bacterial isolates exhibited strong to weak adhesion potential in the biofilm assay.
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Affiliation(s)
- Rajanbir Kaur
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Drishtant Singh
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Anup Kumar Kesavan
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Rajinder Kaur
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143005, India
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Expression of a Shiga-Like Toxin during Plastic Colonization by Two Multidrug-Resistant Bacteria, Aeromonas hydrophila RIT668 and Citrobacter freundii RIT669, Isolated from Endangered Turtles ( Clemmys guttata). Microorganisms 2020; 8:microorganisms8081172. [PMID: 32752245 PMCID: PMC7465454 DOI: 10.3390/microorganisms8081172] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/23/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Aeromonas hydrophila RIT668 and Citrobacter freundii RIT669 were isolated from endangered spotted turtles (Clemmys guttata). Whole-genome sequencing, annotation and phylogenetic analyses of the genomes revealed that the closest relative of RIT668 is A. hydrophila ATCC 7966 and Citrobacter portucalensis A60 for RIT669. Resistome analysis showed that A. hydrophila and C. freundii harbor six and 19 different antibiotic resistance genes, respectively. Both bacteria colonize polyethylene and polypropylene, which are common plastics, found in the environment and are used to fabricate medical devices. The expression of six biofilm-related genes—biofilm peroxide resistance protein (bsmA), biofilm formation regulatory protein subunit R (bssR), biofilm formation regulatory protein subunit S (bssS), biofilm formation regulator (hmsP), toxin-antitoxin biofilm protein (tabA) and transcriptional activator of curli operon (csgD)—and two virulence factors—Vi antigen-related gene (viaB) and Shiga-like toxin (slt-II)—was investigated by RT-PCR. A. hydrophila displayed a > 2-fold increase in slt-II expression in cells adhering to both polymers, C. freundii adhering on polyethylene displayed a > 2-fold, and on polypropylene a > 6-fold upregulation of slt-II. Thus, the two new isolates are potential pathogens owing to their drug resistance, surface colonization and upregulation of a slt-II-type diarrheal toxin on polymer surfaces.
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12
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Bai L, Zhang S, Deng Y, Song C, Kang G, Dong Y, Wang Y, Gao F, Huang H. Comparative genomics analysis of Acinetobacter haemolyticus isolates from sputum samples of respiratory patients. Genomics 2020; 112:2784-2793. [PMID: 32209379 DOI: 10.1016/j.ygeno.2020.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/27/2020] [Accepted: 03/20/2020] [Indexed: 12/25/2022]
Abstract
Acinetobacter haemolyticus (A. haemolyticus) is a significant Acinetobacter pathogen, and the resistance of A. haemolyticus continues to rise due to abuse of antibiotics and the frequent gene exchange between bacteria in hospital. In this study, we performed complete genome sequencing of two A. haemolyticus strains TJR01 and TJS01 to improve our understanding of pathogenic and resistance of A. haemolyticus. Both TJR01 and TJS01 contain one chromosome and two plasmids. Compared to TJS01, more virulence factors (VFs) associated pathogenicity and resistant genes were predicted in TJR01 due to T4SS and integron associated with combination and transport. Antimicrobial susceptibility results were consistent with sequencing. We suppose TJS01 was a susceptive strain and TJR01 was an acquired multidrug resistance strain due to plasmid-mediated horizontal gene transfer. We hope these findings may be helpful for clinical treatment of A. haemolyticus infection and reduce the risk of potential outbreak infection.
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Affiliation(s)
- Liang Bai
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - ShaoCun Zhang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Yong Deng
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, China
| | | | - GuangBo Kang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, China
| | | | - Yue Wang
- Institute of Infectious Diseases, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Feng Gao
- Department of Physics, School of Science, Frontier Science Center of Synthetic Biology (MOE), Key Laboratory of Systems Bioengineering (MOE), Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - He Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, China.
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Koutsoumanis K, Allende A, Alvarez‐Ordóñez A, Bover‐Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Jenkins C, Monteiro Pires S, Morabito S, Niskanen T, Scheutz F, da Silva Felício MT, Messens W, Bolton D. Pathogenicity assessment of Shiga toxin‐producing Escherichia coli (STEC) and the public health risk posed by contamination of food with STEC. EFSA J 2020. [DOI: 10.2903/j.efsa.2020.5967] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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15
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Campos A, Lopes MS, Carvalheira A, Barbosa J, Teixeira P. Survival of clinical and food Acinetobacter spp. isolates exposed to different stress conditions. Food Microbiol 2019; 77:202-207. [PMID: 30297051 DOI: 10.1016/j.fm.2018.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 09/08/2018] [Accepted: 09/11/2018] [Indexed: 12/29/2022]
Abstract
Acinetobacter baumanni is recognized as one of the most important agents of nosocomial infections. Other species such as Acinetobacter lwoffii have also been associated with such infections. These species can be found in food products, such as vegetables, fruits and meats which can be a source of transmission of these organisms to community and hospital settings. Evidence that hospitals' kitchens are a route of entry of pathogenic and antimicrobial-resistant bacteria was recently demonstrated. This study aimed to determine whether different Acinetobacter spp. isolated from human and food samples (lettuce, turkey meat, apple and pear) were resistant to stress conditions often applied in food processes, such as exposure to 60 °C, AMUKINA® and vinegar. Also the influence of food matrices on the behavior of isolates to these stress conditions was evaluated. Treatment with AMUKINA® and vinegar were effective against all clinical and food isolates. Exposure to 60 °C resulted in the reduction of the majority of isolates to values below the detection limit of the enumeration technique, however, it is important to note that most of the reductions only occurred after 30 min of exposure. One food isolate identified as A. baumanni was resistant to this thermal treatment and one clinical isolate only decreased 4 log cycles after 1 h. In general, food isolates were demonstrated to be more resistant than clinical isolates and no significant differences (p > 0.05) were found between A. baumanni and A. lwoffii species. With the exception of one food isolate that was more resistant to thermal stress in the presence of turkey meat, the food matrices investigated did not confer protection to the applied stresses. Due to the limited knowledge on this topic, we believe that this study is an important contribution to understanding the behavior of Acinetobacter spp. when exposed to treatments commonly applied to foods.
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Affiliation(s)
- Ana Campos
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Maria Sequeira Lopes
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Ana Carvalheira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Joana Barbosa
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal
| | - Paula Teixeira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4200-374, Porto, Portugal.
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16
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Hazard Identification and Characterization: Criteria for Categorizing Shiga Toxin-Producing Escherichia coli on a Risk Basis †. J Food Prot 2019; 82:7-21. [PMID: 30586326 DOI: 10.4315/0362-028x.jfp-18-291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Shiga toxin-producing Escherichia coli (STEC) comprise a large, highly diverse group of strains. Since the emergence of STEC serotype O157:H7 as an important foodborne pathogen, serotype data have been used for identifying STEC strains, and this use continued as other serotypes were implicated in human infections. An estimated 470 STEC serotypes have been identified, which can produce one or more of the 12 known Shiga toxin (Stx) subtypes. The number of STEC serotypes that cause human illness varies but is probably higher than 100. However, many STEC virulence genes are mobile and can be lost or transferred to other bacteria; therefore, STEC strains that have the same serotype may not carry the same virulence genes or pose the same risk. Although serotype information is useful in outbreak investigations and surveillance studies, it is not a reliable means of assessing the human health risk posed by a particular STEC serotype. To contribute to the development of a set of criteria that would more reliably support hazard identification, this review considered each of the factors contributing to a negative human health outcome: mild diarrhea, bloody diarrhea, and hemolytic uremic syndrome (HUS). STEC pathogenesis involves entry into the human gut (often via ingestion), attachment to the intestinal epithelial cells, and elaboration of Stx. Production of Stx, which disrupts normal cellular functions and causes cell damage, alone without adherence of bacterial cells to gut epithelial cells is insufficient to cause severe illness. The principal adherence factor in STEC is the intimin protein coded by the eae gene. The aggregative adherence fimbriae adhesins regulated by the aggR gene of enteroaggregative E. coli strains are also effective adherence factors. The stx2a gene is most often present in locus of enterocyte effacement ( eae)-positive STEC strains and has consistently been associated with HUS. The stx2a gene has also been found in eae-negative, aggR-positive STEC that have caused HUS. HUS cases where other stx gene subtypes were identified indicate that other factors such as host susceptibility and the genetic cocktail of virulence genes in individual isolates may affect their association with severe diseases.
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Affiliation(s)
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- The Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA) Secretariat, * Food Safety and Quality Unit, Agriculture and Consumer Protection Department, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00153 Rome, Italy
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17
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Bai X, Fu S, Zhang J, Fan R, Xu Y, Sun H, He X, Xu J, Xiong Y. Identification and pathogenomic analysis of an Escherichia coli strain producing a novel Shiga toxin 2 subtype. Sci Rep 2018; 8:6756. [PMID: 29712985 PMCID: PMC5928088 DOI: 10.1038/s41598-018-25233-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/17/2018] [Indexed: 11/25/2022] Open
Abstract
Shiga toxin (Stx) is the key virulent factor in Shiga toxin-producing Escherichia coli (STEC). To date, three Stx1 subtypes and seven Stx2 subtypes have been described in E. coli, which differed in receptor preference and toxin potency. Here, we identified a novel Stx2 subtype designated Stx2h in E. coli strains isolated from wild marmots in the Qinghai-Tibetan plateau, China. Stx2h shares 91.9% nucleic acid sequence identity and 92.9% amino acid identity to the nearest Stx2 subtype. The expression of Stx2h in type strain STEC299 was inducible by mitomycin C, and culture supernatant from STEC299 was cytotoxic to Vero cells. The Stx2h converting prophage was unique in terms of insertion site and genetic composition. Whole genome-based phylo- and patho-genomic analysis revealed STEC299 was closer to other pathotypes of E. coli than STEC, and possesses virulence factors from other pathotypes. Our finding enlarges the pool of Stx2 subtypes and highlights the extraordinary genomic plasticity of E. coli strains. As the emergence of new Shiga toxin genotypes and new Stx-producing pathotypes pose a great threat to the public health, Stx2h should be further included in E. coli molecular typing, and in epidemiological surveillance of E. coli infections.
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Affiliation(s)
- Xiangning Bai
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Shanshan Fu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Ji Zhang
- mEpiLab, New Zealand Food Safety Science & Research Centre, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Massey, New Zealand
| | - Ruyue Fan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Yanmei Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Hui Sun
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Xiaohua He
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Albany, California, USA
| | - Jianguo Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang Province, China
| | - Yanwen Xiong
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China.
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang Province, China.
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18
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Kilungo A, Powers L, Arnold N, Whelan K, Paterson K, Young D. Evaluation of Well Designs to Improve Access to Safe and Clean Water in Rural Tanzania. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15010064. [PMID: 29300305 PMCID: PMC5800163 DOI: 10.3390/ijerph15010064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 11/16/2017] [Accepted: 12/12/2017] [Indexed: 12/21/2022]
Abstract
The objective of this study was to examine three well designs: drilled wells (20–30 m deep), closed dug wells (>5 m deep), and hand-dug open wells (<5 m deep), to determine the water quality for improving access to safe and clean water in rural communities. Heterotrophic plate count (HPC), total coliforms (TC), Escherichia coli (E. coli) and turbidity, were used to assess the water quality of 97 wells. Additionally, the study looked at the microflora diversity of the water, focusing on potential pathogens using outgrowth, PCR, and genome sequencing for 10 wells. Concentrations of TC for the open dug wells (4 × 104 CFU/100 mL) were higher than the drilled (2 × 103 CFU/100 mL) and closed dug wells (3 × 103 CFU/100 mL). E. coli concentration for drilled and closed dug wells was <22 MPN (most probable number)/100 mL, but higher for open wells (>154 MPN/100 mL). The drilled well turbidity (11 NTU) was within the standard deviation of the closed well (28 NTU) compared to open dug wells (49 NTU). Drilled and closed wells had similar microbial diversity. There were no significant differences between drilled and closed dug wells. The covering and lining of hand-dug wells should be considered as an alternative to improve access to safe and clean water in rural communities.
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Affiliation(s)
- Aminata Kilungo
- Mel and Enid Zuckerman College of Public Health, Health Promotion Sciences Department, The University of Arizona, 1295 N Martin Avenue, Tucson, AZ 85721, USA.
| | - Linda Powers
- Electrical and Computer Engineering, Biomedical Engineering, The University of Arizona, 1230 E. Speedway Blvd, Tucson, AZ 85721, USA.
| | - Nathan Arnold
- Department of Civil and Environmental Engineering, Michigan Technological University, 801 Dow Building, Houghton, MI 49931, USA.
| | - Kelli Whelan
- Department of Civil and Environmental Engineering, Michigan Technological University, 801 Dow Building, Houghton, MI 49931, USA.
| | - Kurt Paterson
- Department of Engineering, James Madison University, 801 Carrier Dr., Harrisonburg, VA 22807, USA.
| | - Dale Young
- Maji Safi kwa Afya Bora Ifakara (MSABI), Kilosa Road 65, Morogoro 284, Tanzania.
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19
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Razaghi M, Tajeddin E, Ganji L, Alebouyeh M, Alizadeh AHM, Sadeghi A, Zali MR. Colonization, resistance to bile, and virulence properties of Escherichia coli strains: Unusual characteristics associated with biliary tract diseases. Microb Pathog 2017; 111:262-268. [PMID: 28867623 DOI: 10.1016/j.micpath.2017.08.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/23/2017] [Accepted: 08/30/2017] [Indexed: 12/18/2022]
Abstract
Escherichia coli is the species that is most frequently isolated from bile of patients with biliary tract diseases. This study was aimed to investigate any association between resistance and virulence properties of these isolates with occurrence of the diseases. A total of 102 bile samples were obtained from patients subjected to endoscopic retrograde cholangiopancreatography for different biliary diseases. Clinical data were collected and culture of the bile samples was done on selective media. Resistance of characterized Escherichia coli isolates to deoxycholate sodium (0-7%) and nineteen antibiotics was determined and PCR using 16 pairs of primers targeting stx1, stx2, exhA, eae, bfp, agg, pcvd432, lt, st, ipaH, pic, pet, ast, set, sen, and cdtB genes was done. Our results showed a statistically significant association between E. coli colonization and existence of common bile duct and gallbladder stones (p value 0.028). Out of the 22 E. coli strains (22/102) multidrug resistance phenotype was present in 95.45%. None of the strains belonged to common E. coli pathotypes. However, bfp + EhxA-hly, bfp + astA, bfp + EhxA-hly + pic, and EhxA-hly + pic + astA, bfp, and astA genotypes were detected in these strains. bfp (7/22, 31.8%) and astA (5/22, 22.7%) were among most frequent virulence factors in these strains. Results of this study showed significant association between colonization of E. coli and choledocholithiasis. Unusual existence of virulence gene combinations in these strains and their resistance to DOC and multiple classes of antibiotics could be considered as possible causes of their persistence in this harsh microenvironment.
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Affiliation(s)
- Maryam Razaghi
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Tajeddin
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Ganji
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoud Alebouyeh
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Science, Tehran, Iran.
| | - Amir Houshang Mohammad Alizadeh
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Amir Sadeghi
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Mohammad Reza Zali
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Science, Tehran, Iran
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20
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MALDI-TOF MS for the Identification of Cultivable Organic-Degrading Bacteria in Contaminated Groundwater near Unconventional Natural Gas Extraction Sites. Microorganisms 2017; 5:microorganisms5030047. [PMID: 28796186 PMCID: PMC5620638 DOI: 10.3390/microorganisms5030047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/21/2017] [Accepted: 08/07/2017] [Indexed: 11/17/2022] Open
Abstract
Groundwater quality and quantity is of extreme importance as it is a source of drinking water in the United States. One major concern has emerged due to the possible contamination of groundwater from unconventional oil and natural gas extraction activities. Recent studies have been performed to understand if these activities are causing groundwater contamination, particularly with respect to exogenous hydrocarbons and volatile organic compounds. The impact of contaminants on microbial ecology is an area to be explored as alternatives for water treatment are necessary. In this work, we identified cultivable organic-degrading bacteria in groundwater in close proximity to unconventional natural gas extraction. Pseudomonas stutzeri and Acinetobacter haemolyticus were identified using matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF MS), which proved to be a simple, fast, and reliable method. Additionally, the potential use of the identified bacteria in water and/or wastewater bioremediation was studied by determining the ability of these microorganisms to degrade toluene and chloroform. In fact, these bacteria can be potentially applied for in situ bioremediation of contaminated water and wastewater treatment, as they were able to degrade both compounds.
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21
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Amorim AMB, Nascimento JDS. A Highlight for Non- Escherichia coli and Non- Salmonella sp. Enterobacteriaceae in Dairy Foods Contamination. Front Microbiol 2017; 8:930. [PMID: 28596761 PMCID: PMC5442226 DOI: 10.3389/fmicb.2017.00930] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 05/08/2017] [Indexed: 12/24/2022] Open
Affiliation(s)
- Angelo M. B. Amorim
- Laboratory of Microbiology, Instituto Federal de Educação, Ciência e Tecnologia do Rio de JaneiroRio de Janeiro, Brazil
- Department of Quality Control, Instituto de Tecnologia em Imunobiológicos Bio-Manguinhos, FiocruzRio de Janeiro, Brazil
| | - Janaína dos Santos Nascimento
- Department of Quality Control, Instituto de Tecnologia em Imunobiológicos Bio-Manguinhos, FiocruzRio de Janeiro, Brazil
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22
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Khalil RKS, Skinner C, Patfield S, He X. Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains. Pathog Dis 2016; 74:ftw037. [PMID: 27109772 DOI: 10.1093/femspd/ftw037] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 10/21/2022] Open
Abstract
Enterobacter cloacae M12X01451 strain recently identified from a clinical specimen produces a new Stx1 subtype (Stx1e) that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and origin/stability of stx1e in M12X01451 is not known. In this study, we confirmed the ability of Stx1a- and Stx1e-converting phages from an Escherichia coli O157:H7 strain RM8530 and M12X01451 respectively to infect several E. coli and Ent. cloacae strains. stx1e was detected in 97.5% and 72.5% of progenies of strains lysogenized by stx1e phage after 10 (T10) and 20 (T20) subcultures, versus 65% and 17.5% for stx1a gene. Infection of M12X01451 and RM8530 with each other's phages generated double lysogens containing both phages. stx1a was lost after T10, whereas the stx1e was maintained even after T20 in M12X01451 lysogens. In RM8530 lysogens, the acquired stx1e was retained with no mutations, but 20% of stx1a was lost after T20 ELISA and western blot analyses demonstrated that Stx1e was produced in all strains lysogenized by stx1e phage; however, Stx1a was not detected in any lysogenized strain. The study results highlight the potential risks of emerging Stx-producing strains via bacteriophages either in the human gastrointestinal tract or in food production environments, which are matters of great concern and may have serious impacts on human health.
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Affiliation(s)
- Rowaida K S Khalil
- Department of Botany and Microbiology, Faculty of Science, Alexandria University, Alexandria 21511, Egypt
| | - Craig Skinner
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA
| | - Stephanie Patfield
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA
| | - Xiaohua He
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA
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Maravić A, Skočibušić M, Fredotović Ž, Šamanić I, Cvjetan S, Knezović M, Puizina J. Urban riverine environment is a source of multidrug-resistant and ESBL-producing clinically important Acinetobacter spp. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3525-3535. [PMID: 26490931 DOI: 10.1007/s11356-015-5586-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Some Acinetobacter species have emerged as very important opportunistic pathogens in humans. We investigated Acinetobacter spp. from the polluted urban riverine environment in Croatia in regard to species affiliation, antibiotic resistance pattern, and resistance mechanisms. Considerable number of isolates produced acquired extended-spectrum β-lactamase(s) (ESBLs), CTX-M-15 solely or with TEM-116. By Southern blot hybridization, bla TEM-116 was identified on plasmids ca. 10, 3, and 1.2 kb in Acinetobacter junii, A. gandensis, and A. johnsonii. The bla TEM-116-carrying plasmid in A. gandensis was successfully transferred by conjugation to azide-resistant Escherichia coli J53. A. radioresistens isolate also carried an intrinsic carbapenemase gene bla OXA-133 with ISAba1 insertion sequence present upstream to promote its expression. Majority of ESBL-producing isolates harbored integrases intI1 and/or intI2 and the sulfamethoxazole resistance gene sul1. Almost all isolates had overexpressed resistance-nodulation-cell division (RND) efflux system, indicating that this mechanism may have contributed to multidrug resistance phenotypes. This is the first report of environmental CTX-M-15-producing Acinetobacter spp. and the first identification of CTX-M-15 in A. johnsonii, A. junii, A. calcoaceticus, A. gandensis, A. haemolyticus, and A. radioresistens worldwide. We identified, also for the first time, the environmental Acinetobacter-producing TEM ESBLs, highlighting the potential risk for human health, and the role of these bacteria in maintenance and dissemination of clinically important antibiotic resistance genes in community through riverine environments.
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Affiliation(s)
- Ana Maravić
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
| | - Mirjana Skočibušić
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia
| | - Željana Fredotović
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia
| | - Ivica Šamanić
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia
| | - Svjetlana Cvjetan
- Department of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia
- Mediterranean Institute for Life Sciences, Meštrovićevo šetalište 45, 21000, Split, Croatia
| | - Mia Knezović
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia
| | - Jasna Puizina
- Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia
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Skinner C, Patfield S, Khalil R, Kong Q, He X. New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum. mSphere 2016; 1:e00099-15. [PMID: 27303707 PMCID: PMC4863616 DOI: 10.1128/msphere.00099-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/03/2016] [Indexed: 01/14/2023] Open
Abstract
Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently discovered in an atypical host (Enterobacter cloacae), is undetectable by many Stx assays. To formulate new assays for the detection of Stx1e, we generated four new MAbs that recognize this Stx subtype. Using these antibodies, we generated an assay capable of detecting Stx1e at low picogram-per-milliliter concentrations. This assay is also compatible with a human serum matrix, suggesting that it may have utility for the clinical detection and diagnosis of Stx1e-associated infections.
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Affiliation(s)
- Craig Skinner
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, California, USA
| | - Stephanie Patfield
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, California, USA
| | - Rowaida Khalil
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, California, USA
| | - Qiulian Kong
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, California, USA
| | - Xiaohua He
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, California, USA
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Gaidhani SV, Raskar AV, Poddar S, Gosavi S, Sahu PK, Pardesi KR, Bhide SV, Chopade BA. Time dependent enhanced resistance against antibiotics & metal salts by planktonic & biofilm form of Acinetobacter haemolyticus MMC 8 clinical isolate. Indian J Med Res 2014; 140:665-71. [PMID: 25579150 PMCID: PMC4311322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND & OBJECTIVES Available literature shows paucity of reports describing antibiotic and metal resistance profile of biofilm forming clinical isolates of Acinetobacter haemolyticus. The present study was undertaken to evaluate the antibiotic and metal resistance profile of Indian clinical isolate of A. haemolyticus MMC 8 isolated from human pus sample in planktonic and biofilm form. METHODS Antibiotic susceptibility and minimum inhibitory concentration were determined employing broth and agar dilution techniques. Biofilm formation was evaluated quantitatively by microtiter plate method and variation in complex architecture was determined by scanning electron microscopy. Minimum biofilm inhibiting concentration was checked by Calgary biofilm device. RESULTS Planktonic A. haemolyticus MMC 8 was sensitive to 14 antibiotics, AgNO 3 and HgC1 2 resistant to streptomycin and intermediately resistant to netilmycin and kanamycin. MMC 8 exhibited temporal variation in amount and structure of biofilm. There was 32-4000 and 4-256 fold increase in antibiotic and metal salt concentration, respectively to inhibit biofilm over a period of 72 h as against susceptible planktonic counterparts. Total viable count in the range of 10(5)-10(6) cfu / ml was observed on plating minimum biofilm inhibiting concentration on Muller-Hinton Agar plate without antimicrobial agents. Biofilm forming cells were several folds more resistant to antibiotics and metal salts in comparison to planktonic cells. Presence of unaffected residual cell population indicated presence of persister cells. INTERPRETATION & CONCLUSIONS The results indicate that biofilm formation causes enhanced resistance against antibiotics and metal salts in otherwise susceptible planktonic A. haemolyticus MMC 8.
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Affiliation(s)
| | | | | | - Shriya Gosavi
- Department of Microbiology, University of Pune, Pune, India
| | | | | | | | - Balu Ananada Chopade
- Institute of Bioinformatics & Biotechnology, University of Pune, Pune, India,Reprint requests: Prof. B.A. Chopade, Department of Microbiology, University of Pune, Pune 411 007, Maharashtra, India e-mail:
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Probert WS, McQuaid C, Schrader K. Isolation and identification of an Enterobacter cloacae strain producing a novel subtype of Shiga toxin type 1. J Clin Microbiol 2014; 52:2346-51. [PMID: 24759708 PMCID: PMC4097712 DOI: 10.1128/jcm.00338-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/12/2014] [Indexed: 11/20/2022] Open
Abstract
We describe here the isolation and identification of a Shiga toxin 1 (Stx1)-producing Enterobacter cloacae strain, M12X01451, from a human clinical specimen. The bacterial isolate was identified as E. cloacae using a polyphasic approach that included phenotypic, genetic, and proteomic analyses. The M12X01451 stx1 was sequenced, and the holotoxin was found to share only 87% amino acid sequence identity with the nearest Stx1 subtype reference sequence. Sequence analysis of the regions immediately flanking stx1 displayed similarities with bacteriophage-related sequences, suggesting a prophage origin. The stx1 gene was a stable element within the M12X01451 genome, as demonstrated by real-time PCR detection following successive subculturing of the bacterial isolate. Culture supernatant from M12X01451 was cytotoxic to Vero cells but was not neutralized by an anti-Stx1 monoclonal antibody. In addition, Stx1 from M12X01451 demonstrated limited antigenicity with two commercially available lateral flow immunoassays. The M12X01451 Stx represents a new Stx1 subtype based on the degree of sequence dissimilarity with Stx1 subtype reference sequences and its limited reactivity with anti-Stx1 antibodies.
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Affiliation(s)
- William S Probert
- Microbial Diseases Laboratory Branch, California Department of Public Health, Richmond, California, USA
| | - Cassandra McQuaid
- Microbial Diseases Laboratory Branch, California Department of Public Health, Richmond, California, USA
| | - Kimmi Schrader
- Microbial Diseases Laboratory Branch, California Department of Public Health, Richmond, California, USA
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da Silva PSL, Lipinski RW. Hemolytic uremic syndrome associated withAcinetobacter hemolyticus. Ren Fail 2014; 36:1122-4. [DOI: 10.3109/0886022x.2014.917575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Somboonna N, Wilantho A, Jankaew K, Assawamakin A, Sangsrakru D, Tangphatsornruang S, Tongsima S. Microbial ecology of Thailand tsunami and non-tsunami affected terrestrials. PLoS One 2014; 9:e94236. [PMID: 24710002 PMCID: PMC3978030 DOI: 10.1371/journal.pone.0094236] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/13/2014] [Indexed: 11/18/2022] Open
Abstract
The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1), as well as a parallel unaffected terrestrial site, non-tsunami affected (S2). S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species.
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Affiliation(s)
- Naraporn Somboonna
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- * E-mail:
| | - Alisa Wilantho
- Genome Institute, National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
| | - Kruawun Jankaew
- Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Anunchai Assawamakin
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Duangjai Sangsrakru
- Genome Institute, National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
| | | | - Sissades Tongsima
- Genome Institute, National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
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Klein JR, Gulsvig T. Using Bioinformatics to Develop and Test Hypotheses: E. coli-Specific Virulence Determinants. JOURNAL OF MICROBIOLOGY & BIOLOGY EDUCATION 2012; 13:161-9. [PMID: 23653804 PMCID: PMC3577336 DOI: 10.1128/jmbe.v13i2.451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bioinformatics, the use of computer resources to understand biological information, is an important tool in research, and can be easily integrated into the curriculum of undergraduate courses. Such an example is provided in this series of four activities that introduces students to the field of bioinformatics as they design PCR based tests for pathogenic E. coli strains. A variety of computer tools are used including BLAST searches at NCBI, bacterial genome searches at the Integrated Microbial Genomes (IMG) database, protein analysis at Pfam and literature research at PubMed. In the process, students also learn about virulence factors, enzyme function and horizontal gene transfer. Some or all of the four activities can be incorporated into microbiology or general biology courses taken by students at a variety of levels, ranging from high school through college. The activities build on one another as they teach and reinforce knowledge and skills, promote critical thinking, and provide for student collaboration and presentation. The computer-based activities can be done either in class or outside of class, thus are appropriate for inclusion in online or blended learning formats. Assessment data showed that students learned general microbiology concepts related to pathogenesis and enzyme function, gained skills in using tools of bioinformatics and molecular biology, and successfully developed and tested a scientific hypothesis.
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Figueiredo S, Bonnin RA, Poirel L, Duranteau J, Nordmann P. Identification of the naturally occurring genes encoding carbapenem-hydrolysing oxacillinases from Acinetobacter haemolyticus, Acinetobacter johnsonii, and Acinetobacter calcoaceticus. Clin Microbiol Infect 2011; 18:907-13. [PMID: 22128805 DOI: 10.1111/j.1469-0691.2011.03708.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Carbapenem resistance is increasingly being reported among Acinetobacter species, and results mostly from the expression of acquired carbapenem-hydrolysing oxacillinases (CHDLs). Several Acinetobacter species intrinsically possess chromosomal CHDL genes: Acinetobacter baumannii (bla(OXA-51) ), Acinetobacter radioresistens (bla(OXA-23) ), and Acinetobacter lwoffii (bla(OXA-134) ). We aimed to identify the progenitors of novel CHDL-encoding genes for identification of potential reservoirs. We performed PCR screening using degenerated internal primers designed from a sequence alignment of the known CHDLs (OXA-23, OXA-40, OXA-51, OXA-58, OXA-134, and OXA-143) applied to a collection of 50 Acinetobacter strains belonging to 23 different species. Two strains of Acinetobacter johnsonii, one strain of Acinetobacter calcoaceticus and two strains of Acinetobacter haemolyticus were found to harbour, respectively, the totally novel bla(OXA-211) -like, bla(OXA-213) -like and bla(OXA-214) -like genes. In addition, the complete genomes of those three species available in GenBank, i.e. one A. johnsonii genome, four A. calcoaceticus genomes, and one A. haemolyticus genome, were analysed and found to be positive for the presence of bla(OXA211) -like, bla(OXA-213) -like and bla(OXA-214) -like genes, respectively. The β-lactamases OXA-211, OXA-213 and OXA-214 are diverse, with amino acid identities ranging from 53% to 76%, as compared with the naturally occurring OXA-51-like CHDL from A. baumannii. These β-lactamases showed a peculiar hydrolysis profile, including mostly penicillins and carbapenems. Regarding bla(OXA-23) in A. radioresistens and bla(OXA-134) in A. lwoffii, these genes were not expressed (or expressed at a non-significant level) in their host. Detection of these β-lactamase genes might be used as a useful tool for accurate identification of these Acinetobacter species.
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Affiliation(s)
- S Figueiredo
- Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotics, Département Anesthésie-Réanimation, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine et Université Paris-Sud, K.-Bicêtre, France
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Soslau G, Russell JA, Spotila JR, Mathew AJ, Bagsiyao P. Acinetobacter sp. HM746599 isolated from leatherback turtle blood. FEMS Microbiol Lett 2011; 322:166-71. [PMID: 21707734 DOI: 10.1111/j.1574-6968.2011.02346.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A newly described bacterial isolate, Acinetobacter sp. HM746599, has been obtained from leatherback sea turtle hatchling blood. The implication is that the hatchling was infected during development in the egg, which is substantiated by other studies to be reported by us in the future. The 16S rRNA gene sequence of the bacterium (GenBank accession number: HM746599) showed the greatest similarity to the identified species, Acinetobacter beijerinckii (97.6-99.78%) and Acinetobacter venetianus (99.78%). Acinetobacter sp. HM746599 are gram-negative, rod-shaped coccobacilli and are hemolytic/cytotoxic to human and sea turtle red blood cells (RBCs). Hemolysis is not the result of any detectable soluble toxin. Acinetobacter beijerinckii and A. venetianus hemolyze sheep RBCs while Acinetobacter sp. HM746599 does not, and unlike A. venetianus, the growth of Acinetobacter sp. HM746599 and A. beijerinckii is not supported by l-arginine. Many Acinetobacter species, especially hemolytic ones, are pathogenic to immunologically compromised humans and it is possible that, in addition to sea turtles, this bacterium might also be a danger to susceptible humans who handle infected hatchlings. The bacteria are available from CCUG (Culture Collection, University Gothenburg, Göteborg, Sweden) and from NRRL (Agricultural Research Service Culture Collection, Peoria, IL).
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Affiliation(s)
- Gerald Soslau
- Office of Professional Studies in the Health Sciences, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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Shiga toxin: expression, distribution, and its role in the environment. Toxins (Basel) 2011; 3:608-25. [PMID: 22069728 PMCID: PMC3202840 DOI: 10.3390/toxins3060608] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/09/2011] [Accepted: 06/09/2011] [Indexed: 11/17/2022] Open
Abstract
In this review, we highlight recent work that has increased our understanding of the production and distribution of Shiga toxin in the environment. Specifically, we review studies that offer an expanded view of environmental reservoirs for Shiga toxin producing microbes in terrestrial and aquatic ecosystems. We then relate the abundance of Shiga toxin in the environment to work that demonstrates that the genetic mechanisms underlying the production of Shiga toxin genes are modified and embellished beyond the classical microbial gene regulatory paradigms in a manner that apparently "fine tunes" the trigger to modulate the amount of toxin produced. Last, we highlight several recent studies examining microbe/protist interactions that postulate an answer to the outstanding question of why microbes might harbor and express Shiga toxin genes in the environment.
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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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34
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Fagerquist CK, Sultan O. Induction and identification of disulfide-intact and disulfide-reduced β-subunit of Shiga toxin 2 from Escherichia coli O157:H7 using MALDI-TOF-TOF-MS/MS and top-down proteomics. Analyst 2011; 136:1739-46. [PMID: 21336382 DOI: 10.1039/c0an00909a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The disulfide-intact and disulfide-reduced β-subunit of Shiga toxin 2 (β-Stx2) from Escherichia coli O157:H7 (strain EDL933) has been identified by matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomic analysis using software developed in-house. E. coli O157:H7 was induced to express Stx2 by culturing on solid agar media supplemented with 10-50 ng mL(-1) of ciprofloxacin (CP). Bacterial cell lysates at each CP concentration were analyzed by MALDI-TOF-MS. A prominent ion at mass-to-charge (m/z) ~7820 was observed for the CP concentration range: 10-50 ng mL(-1), reaching a maximum signal intensity at 20 ng mL(-1). Complex MS/MS data were obtained of the ion at m/z ~7820 by post-source decay resulting in top-down proteomic identification as the mature, signal peptide-removed, disulfide-intact β-Stx2. Eight fragment ion triplets (each spaced Δm/z ~33 apart) were also observed resulting from backbone cleavage between the two cysteine residues (that form the intra-molecular disulfide bond) and symmetric and asymmetric cleavage of the disulfide bond. The middle fragment ion of each triplet, from symmetric disulfide bond cleavage, was matched to an in silico fragment ion formed from cleavage of the backbone at a site adjacent to an aspartic acid or glutamic acid residue. The flanking fragment ions of each triplet, from asymmetric disulfide bond cleavage, were not matched because their corresponding in silico fragment ions are not represented in the database. Easier to interpret MS/MS data were obtained for the disulfide-reduced β-Stx2 which resulted in an improved top-down identification.
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Affiliation(s)
- Clifton K Fagerquist
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, CA 94710, USA.
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35
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Top-down proteomic identification of furin-cleaved α-subunit of Shiga toxin 2 from Escherichia coli O157:H7 using MALDI-TOF-TOF-MS/MS. J Biomed Biotechnol 2011; 2010:123460. [PMID: 21331368 PMCID: PMC3038467 DOI: 10.1155/2010/123460] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 12/17/2010] [Indexed: 01/12/2023] Open
Abstract
A method has been developed to identify the α-subunit of Shiga toxin 2 (α-Stx2) from Escherichia coli O157:H7 using matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomics using web-based software developed in-house. Expression of Stx2 was induced by culturing E. coli O157:H7 on solid agar supplemented with an antibiotic that elicits the bacterial SOS-response. Bacterial cell lysates were incubated in the presence of furin, a human enzyme, that cleaves α-Stx2 into A1 (~28 kDa) and A2 (~5 kDa) protein fragments. A subsequent disulfide reduction step unlinked A1 from A2. MALDI-TOF-MS of the furin-digested/disulfide-reduced sample showed a peak at mass-to-charge (m/z) 5286 that corresponded to the A2 fragment. No peak was observed that corresponded to the A1 fragment although its presence was confirmed by bottom-up proteomics. The peak at m/z 5286 was definitively identified by MALDI-TOF-TOF-MS/MS and top-down proteomics as the A2 fragment of α-Stx2.
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De Jonghe V, Coorevits A, Van Hoorde K, Messens W, Van Landschoot A, De Vos P, Heyndrickx M. Influence of storage conditions on the growth of Pseudomonas species in refrigerated raw milk. Appl Environ Microbiol 2011; 77:460-70. [PMID: 21115713 PMCID: PMC3020527 DOI: 10.1128/aem.00521-10] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 10/31/2010] [Indexed: 11/20/2022] Open
Abstract
The refrigerated storage of raw milk throughout the dairy chain prior to heat treatment creates selective conditions for growth of psychrotolerant bacteria. These bacteria, mainly belonging to the genus Pseudomonas, are capable of producing thermoresistant extracellular proteases and lipases, which can cause spoilage and structural defects in pasteurized and ultra-high-temperature-treated milk (products). To map the influence of refrigerated storage on the growth of these pseudomonads, milk samples were taken after the first milking turn and incubated laboratory scale at temperatures simulating optimal and suboptimal preprocessing storage conditions. The outgrowth of Pseudomonas members was monitored over time by means of cultivation-independent denaturing gradient gel electrophoresis (DGGE). Isolates were identified by a polyphasic approach. These incubations revealed that outgrowth of Pseudomonas members occurred from the beginning of the dairy chain (farm tank) under both optimal and suboptimal storage conditions. An even greater risk for outgrowth, as indicated by a vast increase of about 2 log CFU per ml raw milk, existed downstream in the chain, especially when raw milk was stored under suboptimal conditions. This difference in Pseudomonas outgrowth between optimal and suboptimal storage was already statistically significant within the farm tank. The predominant taxa were identified as Pseudomonas gessardii, Pseudomonas gessardii-like, Pseudomonas fluorescens-like, Pseudomonas lundensis, Pseudomonas fragi, and Pseudomonas fragi-like. Those taxa show an important spoilage potential as determined on elective media for proteolysis and lipolysis.
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Affiliation(s)
- Valerie De Jonghe
- Institute for Agricultural and Fisheries Research (ILVO), Technology & Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
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Doughari HJ, Ndakidemi PA, Human IS, Benade S. The Ecology, Biology and Pathogenesis of Acinetobacter spp.: An Overview. Microbes Environ 2011; 26:101-12. [DOI: 10.1264/jsme2.me10179] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | | | - Spinney Benade
- Applied Sciences Faculty, Cape Peninsula University of Technology
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Bhargava N, Sharma P, Capalash N. Quorum sensing in Acinetobacter: an emerging pathogen. Crit Rev Microbiol 2010; 36:349-60. [PMID: 20846031 DOI: 10.3109/1040841x.2010.512269] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Acinetobacter is emerging as one of the major nosocomial infectious pathogens, facilitated by tolerance to desiccation and multidrug resistance. Quorum sensing (autoinducer-receptor mechanism) plays role in biofilm formation in Acinetobacter, though its role in regulation of other virulence factors is yet to be established. Phylogenetic studies indicate that Acinetobacter baumannii is closely related to Burkholderia ambifaria but its quorum sensing genes (abaI and abaR) were acquired horizontally from Halothiobacillus neapolitanus. The prospects of quorum quenching to control the infections caused by Acinetobacter have also been discussed.
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Affiliation(s)
- Nidhi Bhargava
- Department of Biotechnology, Panjab University, Chandigarh, India
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Abstract
Acinetobacter baumannii has emerged as a highly troublesome pathogen for many institutions globally. As a consequence of its immense ability to acquire or upregulate antibiotic drug resistance determinants, it has justifiably been propelled to the forefront of scientific attention. Apart from its predilection for the seriously ill within intensive care units, A. baumannii has more recently caused a range of infectious syndromes in military personnel injured in the Iraq and Afghanistan conflicts. This review details the significant advances that have been made in our understanding of this remarkable organism over the last 10 years, including current taxonomy and species identification, issues with susceptibility testing, mechanisms of antibiotic resistance, global epidemiology, clinical impact of infection, host-pathogen interactions, and infection control and therapeutic considerations.
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Allison HE. Stx-phages: drivers and mediators of the evolution of STEC and STEC-like pathogens. Future Microbiol 2007; 2:165-74. [PMID: 17661653 DOI: 10.2217/17460913.2.2.165] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bacteriophages, also known as phages, are viruses that infect bacteria. Until recently they have been ignored by most of the scientific community, but their impact upon our world is enormous. They are the most abundant lifeform on the globe and drive the diversity and abundance of bacteria around us, including, in many instances, the pathogenic profiles of many of mankind's most feared bacterial pathogens. This article focuses on how a group of bacteriophages, Stx-phages, which carry the genes encoding Shiga toxin, have driven and are driving the emergence of Shiga toxin-producing pathogens such as the infamous Escherichia coli O157:H7. Since the emergence of this foodborne pathogen as a cause of significant human disease in 1982, more than 500 different serogroups of E. coli have been reported to produce Shiga toxin, as well as a few other organisms. These events and many more are all controlled by the biology of Stx-phages.
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Affiliation(s)
- Heather E Allison
- University of Liverpool, School of Biological Sciences, Division of Integrative Biology, BioSciences Building, Liverpool, Merseyside, UK.
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Lee JE, Reed J, Shields MS, Spiegel KM, Farrell LD, Sheridan PP. Phylogenetic analysis of Shiga toxin 1 and Shiga toxin 2 genes associated with disease outbreaks. BMC Microbiol 2007; 7:109. [PMID: 18053224 PMCID: PMC2211750 DOI: 10.1186/1471-2180-7-109] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 12/04/2007] [Indexed: 11/29/2022] Open
Abstract
Background Shiga toxins 1 and 2 (Stx1 and Stx2) are bacteriophage-encoded proteins that have been associated with hemorrhagic colitis, hemolytic uremic syndrome and other severe disease conditions. Stx1 and Stx2 are genetically and immunologically distinct but share the same compound toxin structure, method of entry and enzymatic function. Results Phylogenetic analysis was performed using Stx1 and Stx2 amino acid and nucleotide sequences from 41 strains of Escherichia coli, along with known stx sequences available from GenBank. The analysis confirmed the Stx1 and Stx2 divergence, and showed that there is generally more sequence variation among stx2 genes than stx1. The phylograms showed generally flat topologies among our strains' stx1 and stx2 genes. In the stx2 gene, 39.5% of the amino acid sites display very low nonsynonymous to synonymous substitution ratios. Conclusion The stx1 and stx2 genes used in this phylogenetic study show sequence conservation with no significant divergence with respect to place or time. These data could indicate that Shiga toxins are experiencing purifying selection.
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Affiliation(s)
- James E Lee
- Department of Biological Sciences, Idaho State University, 921 South 8th Ave,, Pocatello, ID 83209-8007, USA.
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Smith DL, James CE, Sergeant MJ, Yaxian Y, Saunders JR, McCarthy AJ, Allison HE. Short-tailed stx phages exploit the conserved YaeT protein to disseminate Shiga toxin genes among enterobacteria. J Bacteriol 2007; 189:7223-33. [PMID: 17693515 PMCID: PMC2168440 DOI: 10.1128/jb.00824-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 07/17/2007] [Indexed: 11/20/2022] Open
Abstract
Infection of Escherichia coli by Shiga toxin-encoding bacteriophages (Stx phages) was the pivotal event in the evolution of the deadly Shiga toxin-encoding E. coli (STEC), of which serotype O157:H7 is the most notorious. The number of different bacterial species and strains reported to produce Shiga toxin is now more than 500, since the first reported STEC infection outbreak in 1982. Clearly, Stx phages are spreading rapidly, but the underlying mechanism for this dissemination has not been explained. Here we show that an essential and highly conserved gene product, YaeT, which has an essential role in the insertion of proteins in the gram-negative bacterial outer membrane, is the surface molecule recognized by the majority (ca. 70%) of Stx phages via conserved tail spike proteins associated with a short-tailed morphology. The yaeT gene was initially identified through complementation, and its role was confirmed in phage binding assays with and without anti-YaeT antiserum. Heterologous cloning of E. coli yaeT to enable Stx phage adsorption to Erwinia carotovora and the phage adsorption patterns of bacterial species possessing natural yaeT variants further supported this conclusion. The use of an essential and highly conserved protein by the majority of Stx phages is a strategy that has enabled and promoted the rapid spread of shigatoxigenic potential throughout multiple E. coli serogroups and related bacterial species. Infection of commensal bacteria in the mammalian gut has been shown to amplify Shiga toxin production in vivo, and the data from this study provide a platform for the development of a therapeutic strategy to limit this YaeT-mediated infection of the commensal flora.
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Affiliation(s)
- Darren L Smith
- Microbiology Research Group, BioSciences Building, School of Biological Sciences, University of Liverpool, Crown Street, Liverpool, Merseyside, UK
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