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Lee J, Cha I, Lee K, Son YK, Cho S, Seol D. Complete genome sequence and potential pathogenic assessment of Flavobacterium plurextorum RSG-18 isolated from the gut of Schlegel's black rockfish, Sebastes schlegelii. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13226. [PMID: 38298071 PMCID: PMC10878011 DOI: 10.1111/1758-2229.13226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 12/04/2023] [Indexed: 02/02/2024]
Abstract
Flavobacterium plurextorum is a potential fish pathogen of interest, previously isolated from diseased rainbow trout (Oncorhynchus mykiss) and oomycete-infected chum salmon (Oncorhynchus keta) eggs. We report here the first complete genome sequence of F. plurextorum RSG-18 isolated from the gut of Schlegel's black rockfish (Sebastes schlegelii). The genome of RSG-18 consists of a circular chromosome of 5,610,911 bp with a 33.57% GC content, containing 4858 protein-coding genes, 18 rRNAs, 63 tRNAs and 1 tmRNA. A comparative analysis was conducted on 11 Flavobacterium species previously reported as pathogens or isolated from diseased fish to confirm the potential pathogenicity of RSG-18. In the SEED classification, RSG-18 was found to have 36 genes categorized in 'Virulence, Disease and Defense'. Across all Flavobacterium species, a total of 16 antibiotic resistance genes and 61 putative virulence factors were identified. All species had at least one phage region and type I, III and IX secretion systems. In pan-genomic analysis, core genes consist of genes linked to phages, integrases and matrix-tolerated elements associated with pathology. The complete genome sequence of F. plurextorum RSG-18 will serve as a foundation for future research, enhancing our understanding of Flavobacterium pathogenicity in fish and contributing to the development of effective prevention strategies.
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Affiliation(s)
- Jisol Lee
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulSouth Korea
| | - In‐Tae Cha
- Microorganism Resources DivisionNational Institute of Biological ResourcesIncheonSouth Korea
| | - Ki‐Eun Lee
- Microorganism Resources DivisionNational Institute of Biological ResourcesIncheonSouth Korea
| | - Youn Kyoung Son
- Microorganism Resources DivisionNational Institute of Biological ResourcesIncheonSouth Korea
| | | | - Donghyeok Seol
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulSouth Korea
- Department of SurgerySeoul National University Bundang HospitalSeongnamSouth Korea
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Ferri G, Lauteri C, Vergara A. Antibiotic Resistance in the Finfish Aquaculture Industry: A Review. Antibiotics (Basel) 2022; 11:1574. [PMID: 36358229 PMCID: PMC9686606 DOI: 10.3390/antibiotics11111574] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/25/2022] [Accepted: 11/06/2022] [Indexed: 11/07/2023] Open
Abstract
Significant challenges to worldwide sustainable food production continue to arise from environmental change and consistent population growth. In order to meet increasing demand, fish production industries are encouraged to maintain high growth densities and to rely on antibiotic intervention throughout all stages of development. The inappropriate administering of antibiotics over time introduces selective pressure, allowing the survival of resistant bacterial strains through adaptive pathways involving transferable nucleotide sequences (i.e., plasmids). This is one of the essential mechanisms of antibiotic resistance development in food production systems. This review article focuses on the main international regulations and governing the administering of antibiotics in finfish husbandry and summarizes recent data regarding the distribution of bacterial resistance in the finfish aquaculture food production chain. The second part of this review examines promising alternative approaches to finfish production, sustainable farming techniques, and vaccination that circumvents excessive antibiotic use, including new animal welfare measures. Then, we reflect on recent adaptations to increasingly interdisciplinary perspectives in the field and their greater alignment with the One Health initiative.
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Affiliation(s)
- Gianluigi Ferri
- Faculty of Veterinary Medicine, Post-Graduate Specialization School in Food Inspection “G. Tiecco”, University of Teramo, Strada Provinciale 18, 64100 Teramo, Italy
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Gieseker CM, Gaunt PS, Hawke JP, Crosby TC, Hasbrouck NR, Gao DX, Declercq AM. Epidemiological Cutoff Values for Standard Broth Microdilution Susceptibility Testing of Flavobacterium columnare Isolated from Fishes. Microb Drug Resist 2022; 28:948-955. [PMID: 35972354 DOI: 10.1089/mdr.2022.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Flavobacterium columnare, the causative agent of columnaris disease in a large variety of freshwater fish, is a major problem in commercial aquaculture. A limited number of antimicrobial therapies are available to control this disease; therefore, these agents must be used judiciously. To facilitate effective monitoring for changes in susceptibility, the Clinical Laboratory Standards Institute (CLSI) has a standard broth microdilution test method specific for F. columnare. However, there are no CLSI-approved criteria (termed epidemiological cutoff values [ECVs]) to interpret results. Nevertheless, researchers have developed provisional ECVs based on testing by one laboratory. To satisfy CLSI data requirements, three laboratories used the standard method to generate additional antimicrobial susceptibility data against ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, oxolinic acid, oxytetracycline, sulfadimethoxine/ormetoprim, and sulfamethoxazole-trimethoprim using 109 F. columnare isolates. The new data combined with previously published data from 120 F. columnare isolates were analyzed and ECVs proposed to CLSI. Of the 10 antimicrobials, ECVs were approved for ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, oxolinic acid, and oxytetracycline, which were published in the 2020 edition of the CLSI document VET04 performance standards. These ECVs will help microbiologists categorize decreased antimicrobial susceptibility among F. columnare and will help in surveillance efforts to ensure judicious antimicrobial use.
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Affiliation(s)
- Charles M Gieseker
- Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA
| | - Patricia S Gaunt
- Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA
| | - John P Hawke
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Tina C Crosby
- Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA
| | - Nicholas R Hasbrouck
- Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA
| | - Dana X Gao
- Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA
| | - Annelies M Declercq
- Department of Animal Sciences and Aquatic Ecology, Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium.,Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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In Vivo Bacteriophages’ Application for the Prevention and Therapy of Aquaculture Animals–Chosen Aspects. Animals (Basel) 2022; 12:ani12101233. [PMID: 35625078 PMCID: PMC9137707 DOI: 10.3390/ani12101233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/07/2022] [Accepted: 05/09/2022] [Indexed: 12/14/2022] Open
Abstract
To meet the nutritional requirements of our growing population, animal production must double by 2050, and due to the exhaustion of environmental capacity, any growth will have to come from aquaculture. Aquaculture is currently undergoing a dynamic development, but the intensification of production increases the risk of bacterial diseases. In recent years, there has been a drastic development in the resistance of pathogenic bacteria to antibiotics and chemotherapeutic agents approved for use, which has also taken place in aquaculture. Consequently, animal mortality and economic losses in livestock have increased. The use of drugs in closed systems is an additional challenge as it can damage biological filters. For this reason, there has been a growing interest in natural methods of combating pathogens. One of the methods is the use of bacteriophages both for prophylactic purposes and therapy. This work summarizes the diverse results of the in vivo application of bacteriophages for the prevention and control of bacterial pathogens in aquatic animals to provide a reference for further research on bacteriophages in aquaculture and to compare major achievements in the field.
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Hossain A, Habibullah-Al-Mamun M, Nagano I, Masunaga S, Kitazawa D, Matsuda H. Antibiotics, antibiotic-resistant bacteria, and resistance genes in aquaculture: risks, current concern, and future thinking. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:11054-11075. [PMID: 35028843 DOI: 10.1007/s11356-021-17825-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Aquaculture is remarkably one of the most promising industries among the food-producing industries in the world. Aquaculture production as well as fish consumption per capita have been dramatically increasing over the past two decades. Shifting of culture method from semi-intensive to intensive technique and applying of antibiotics to control the disease outbreak are the major factors for the increasing trend of aquaculture production. Antibiotics are usually present at subtherapeutic levels in the aquaculture environment, which increases the selective pressure to the resistant bacteria and stimulates resistant gene transfer in the aquatic environment. It is now widely documented that antibiotic resistance genes and resistant bacteria are transported from the aquatic environment to the terrestrial environment and may pose adverse effects on human and animal health. However, data related to antibiotic usage and bacterial resistance in aquaculture is very limited or even absent in major aquaculture-producing countries. In particular, residual levels of antibiotics in fish and shellfish are not well documented. Recently, some of the countries have already decided the maximum residue levels (MRLs) of antibiotics in fish muscle or skin; however, many antibiotics are yet not to be decided. Therefore, an urgent universal effort needs to be taken to monitor antibiotic concentration and resistant bacteria particularly multiple antibiotic-resistant bacteria and to assess the associated risks in aquaculture. Finally, we suggest to take an initiative to make a uniform antibiotic registration process, to establish the MRLs for fish/shrimp and to ensure the use of only aquaculture antibiotics in fish and shellfish farming globally.
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Affiliation(s)
- Anwar Hossain
- Department of Fisheries, Faculty of Biological Sciences, University of Dhaka, Dhaka, 1000, Bangladesh.
| | - Md Habibullah-Al-Mamun
- Department of Fisheries, Faculty of Biological Sciences, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Ichiro Nagano
- Central Research Laboratory, Tokyo Innovation Center, Nippon Suisan Kaisha Ltd, 32-3 Nanakuni 1-Chome, Hacjioji, Tokyo, 192-0991, Japan
| | - Shigeki Masunaga
- Faculty of Environment and Information Sciences, Yokohama National University, Yokohama, 240-8501, Japan
| | - Daisuke Kitazawa
- Center for Integrated Underwater Observation Technology, Institute of Industrial Science, The University of Tokyo, Chiba, 277-8574, Japan
| | - Hiroyuki Matsuda
- Faculty of Environment and Information Sciences, Yokohama National University, Yokohama, 240-8501, Japan
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Koutsoumanis K, Allende A, Álvarez‐Ordóñez A, Bolton D, Bover‐Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Ru G, Simmons M, Skandamis P, Suffredini E, Argüello H, Berendonk T, Cavaco LM, Gaze W, Schmitt H, Topp E, Guerra B, Liébana E, Stella P, Peixe L. Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain. EFSA J 2021; 19:e06651. [PMID: 34178158 PMCID: PMC8210462 DOI: 10.2903/j.efsa.2021.6651] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The role of food-producing environments in the emergence and spread of antimicrobial resistance (AMR) in EU plant-based food production, terrestrial animals (poultry, cattle and pigs) and aquaculture was assessed. Among the various sources and transmission routes identified, fertilisers of faecal origin, irrigation and surface water for plant-based food and water for aquaculture were considered of major importance. For terrestrial animal production, potential sources consist of feed, humans, water, air/dust, soil, wildlife, rodents, arthropods and equipment. Among those, evidence was found for introduction with feed and humans, for the other sources, the importance could not be assessed. Several ARB of highest priority for public health, such as carbapenem or extended-spectrum cephalosporin and/or fluoroquinolone-resistant Enterobacterales (including Salmonella enterica), fluoroquinolone-resistant Campylobacter spp., methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium and E. faecalis were identified. Among highest priority ARGs bla CTX -M, bla VIM, bla NDM, bla OXA -48-like, bla OXA -23, mcr, armA, vanA, cfr and optrA were reported. These highest priority bacteria and genes were identified in different sources, at primary and post-harvest level, particularly faeces/manure, soil and water. For all sectors, reducing the occurrence of faecal microbial contamination of fertilisers, water, feed and the production environment and minimising persistence/recycling of ARB within animal production facilities is a priority. Proper implementation of good hygiene practices, biosecurity and food safety management systems is very important. Potential AMR-specific interventions are in the early stages of development. Many data gaps relating to sources and relevance of transmission routes, diversity of ARB and ARGs, effectiveness of mitigation measures were identified. Representative epidemiological and attribution studies on AMR and its effective control in food production environments at EU level, linked to One Health and environmental initiatives, are urgently required.
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Declercq AM, Tilleman L, Gansemans Y, De Witte C, Haesebrouck F, Van Nieuwerburgh F, Smet A, Decostere A. Comparative genomics of Flavobacterium columnare unveils novel insights in virulence and antimicrobial resistance mechanisms. Vet Res 2021; 52:18. [PMID: 33579339 PMCID: PMC7881675 DOI: 10.1186/s13567-021-00899-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/18/2021] [Indexed: 11/28/2022] Open
Abstract
This study reports the comparative analyses of four Flavobacterium columnare isolates that have different virulence and antimicrobial resistance patterns. The main research goal was to reveal new insights into possible virulence genes by comparing the genomes of bacterial isolates that could induce tissue damage and mortality versus the genome of a non-virulent isolate. The results indicated that only the genomes of the virulent isolates possessed unique genes encoding amongst others a methyl-accepting chemotaxis protein possibly involved in the initial colonization of tissue, and several VgrG proteins engaged in interbacterial competition. Furthermore, comparisons of genes unique for the genomes of the highly virulent (HV) carp and trout isolates versus the, respectively, low and non-virulent carp and trout isolates were performed. An important part of the identified unique virulence genes of the HV-trout isolate was located in one particular gene region identified as a genomic island. This region contained araC and nodT genes, both linked to pathogenic and multidrug-resistance, and a luxR-gene, functional in bacterial cell-to-cell communication. Furthermore, the genome of the HV-trout isolate possessed unique sugar-transferases possibly important in bacterial adhesion. The second research goal was to obtain insights into the genetic basis of acquired antimicrobial resistance. Several point-mutations were discovered in gyrase-genes of an isolate showing phenotypic resistance towards first and second-generation quinolones, which were absent in isolates susceptible to quinolones. Tetracycline-resistance gene tetA was found in an isolate displaying acquired phenotypic resistance towards oxytetracycline. Although not localized on a prophage, several flanking genes were indicative of the gene’s mobile character.
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Affiliation(s)
- Annelies Maria Declercq
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium. .,Flanders Marine Institute, Wandelaarkaai 7, 8400, Ostend, Belgium. .,Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
| | - Laurentijn Tilleman
- Laboratory of Pharmaceutical Biotechnology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Yannick Gansemans
- Laboratory of Pharmaceutical Biotechnology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Chloë De Witte
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Filip Van Nieuwerburgh
- Laboratory of Pharmaceutical Biotechnology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Annemieke Smet
- Laboratory Experimental Medicine and Pediatrics, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Annemie Decostere
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
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Shen Y, Zhang R, Schwarz S, Wu C, Shen J, Walsh TR, Wang Y. Farm animals and aquaculture: significant reservoirs of mobile colistin resistance genes. Environ Microbiol 2020; 22:2469-2484. [PMID: 32114703 DOI: 10.1111/1462-2920.14961] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 12/19/2022]
Abstract
Colistin resistance has attracted substantial attention after colistin was considered as a last-resort drug for the treatment of infections caused by carbapenem-resistant and/or multidrug-resistant (MDR) Gram-negative bacteria in clinical settings. However, with the discovery of highly mobile colistin resistance (mcr) genes, colistin resistance has become an increasingly urgent issue worldwide. Despite many reviews, which summarized the prevalence, mechanisms, and structures of these genes in bacteria of human and animal origin, studies on the prevalence of mobile colistin resistance genes in aquaculture and their transmission between animals and humans remain scarce. Herein, we review recent reports on the prevalence of colistin resistance genes in animals, especially wildlife and aquaculture, and their possibility of transmission to humans via the food chain. This review also gives some insights into the routine surveillance, changing policy and replacement of polymyxins by polymyxin derivatives, molecular inhibitors, and traditional Chinese medicine to tackle colistin resistance.
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Affiliation(s)
- Yingbo Shen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.,CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Rong Zhang
- The Second Affiliated Hospital of Zhejiang University, Zhejiang University, Hangzhou, 310009, China
| | - Stefan Schwarz
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, 14163, Germany
| | - Congming Wu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Jianzhong Shen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Timothy R Walsh
- Department of Medical Microbiology and Infectious Disease, Institute of Infection & Immunity, UHW Main Building, Heath Park Hospital, Cardiff, CF14 4XN, UK
| | - Yang Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
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Sundell K, Landor L, Nicolas P, Jørgensen J, Castillo D, Middelboe M, Dalsgaard I, Donati VL, Madsen L, Wiklund T. Phenotypic and Genetic Predictors of Pathogenicity and Virulence in Flavobacterium psychrophilum. Front Microbiol 2019; 10:1711. [PMID: 31396199 PMCID: PMC6668605 DOI: 10.3389/fmicb.2019.01711] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/11/2019] [Indexed: 02/05/2023] Open
Abstract
Flavobacterium psychrophilum causes bacterial cold-water disease (BCWD) in farmed rainbow trout (Oncorhynchus mykiss), with the multilocus sequence typing (MLST) clonal complex (CC) CC-ST10 accounting for the majority of outbreaks globally. The development of alternative strategies to antibiotic treatment of BCWD using bacteriophage-based control of F. psychrophilum, or virulence factors as targets for therapy, requires knowledge of the phage-sensitivity of outbreak strains and of universal traits contributing to their pathogenicity. To examine the association between virulence and both genetic (MLST sequence type (ST) and PCR-serotype) and phenotypic characteristics (adherence, antibiotic resistance, colony spreading motility, hemolytic and proteolytic activity), the median lethal dose (LD50) of 26 geographically disparate F. psychrophilum isolates was determined in rainbow trout. Furthermore, the in vitro sensitivity of the isolates against five bacteriophages was determined by the efficiency of plating (EOP). The tested F. psychrophilum isolates were mainly represented by CC-ST10 genotypes (22 out of 26) and showed up to 3-log differences in LD50 (8.9 × 103 to 3.1 × 106 CFU). No association between MLST ST and virulence was found because of a high variation in LD50 within STs. All identified serotypes (0, 1, and 2) were pathogenic, but ten most virulent isolates belonged to serotype 1 or 2. Isolates of high (LD50 < 105 CFU), moderate (LD50 = 105–106 CFU), and weak (LD50 > 106 CFU) virulence were similar in phenotypic characteristics in vitro. However, the only non-virulent CC-ST10 isolate was deficient in spreading motility and proteolytic activity, indicating that the characteristics are required for pathogenicity in F. psychrophilum. Univariate correlation studies found only non-significant associations between LD50 and the measured phenotypic characteristics, and the multivariable analysis did neither reveal any significant predictors of virulence. The majority of isolates (16 out of 26) were sensitive to at least four bacteriophages, with up to a 6-log variation in the EOP. Most CC-ST10 isolates (16 out of 22) were sensitive to the examined phages, including 5 out of the 7 most virulent isolates represented by prevalent and antibiotic-resistant STs. Our findings suggest that control of BCWD using lytic phages or interventions targeting shared characteristics of pathogenic F. psychrophilum strains should be further explored.
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Affiliation(s)
- Krister Sundell
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Lotta Landor
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Pierre Nicolas
- Unité Mathématiques et Informatique Appliquées du Génome à l'Environnement (MaIAGE), Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jóhanna Jørgensen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Inger Dalsgaard
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Valentina Laura Donati
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lone Madsen
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
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Mata W, Putita C, Dong HT, Kayansamruaj P, Senapin S, Rodkhum C. Quinolone-resistant phenotype of Flavobacterium columnare isolates harbouring point mutations both in gyrA and parC but not in gyrB or parE. J Glob Antimicrob Resist 2018; 15:55-60. [PMID: 29807204 DOI: 10.1016/j.jgar.2018.05.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The aim of this study was to determine mutations associated with a quinolone-resistant (QR) phenotype of Flavobacterium columnare isolates. METHODS The susceptibility of 53 F. columnare isolates to 11 antimicrobials, including 2 quinolones, was investigated by the disk diffusion method. Oxolinic acid (OXO) was subsequently chosen for minimum inhibitory concentration (MIC) assay. Sequence analysis of four genes within the quinolone resistance-determining regions (QRDRs) of OXO-resistant F. columnare compared with susceptible isolates was subsequently performed. RESULTS The disk diffusion assay revealed that the majority of isolates were susceptible to all tested antimicrobials. However, 14 and 8 isolates were resistant to the quinolone antibiotics OXO and nalidixic acid, respectively. No multidrug resistance was observed. The MIC assay revealed five additional isolates that were resistant to OXO (≥4μg/mL), making a total of 19 OXO-resistant isolates observed in this study. DNA sequencing identified missense mutations both in parC and gyrA but not in gyrB or parE in QR F. columnare isolates. Mutation in parC resulted in the change His87→Tyr. For gyrA, 15 isolates of Thai origin exhibited a change at residue Ser83 to either Phe, Tyr or Ala, whereas 3 Vietnamese isolates contained two mutation sites (Ser83→Phe and Asp87→Tyr). CONCLUSION This study is the first to reveal that QR phenotype F. columnare isolates harboured missense mutations both in parC and gyrA but not in gyrB or parE of the QRDRs.
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Affiliation(s)
- W Mata
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - C Putita
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - H T Dong
- Department of Microbiology, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - P Kayansamruaj
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - S Senapin
- Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok, Thailand; National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - C Rodkhum
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand; Fish Infectious Diseases Research Unit (FIDs RU), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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Van Vliet D, Loch TP, Smith P, Faisal M. Antimicrobial Susceptibilities of Flavobacterium psychrophilum Isolates from the Great Lakes Basin, Michigan. Microb Drug Resist 2017; 23:791-798. [DOI: 10.1089/mdr.2016.0103] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Danielle Van Vliet
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, Michigan
| | - Thomas P. Loch
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Peter Smith
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Mohamed Faisal
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, Michigan
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
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Verner-Jeffreys DW, Brazier T, Perez RY, Ryder D, Card RM, Welch TJ, Hoare R, Ngo T, McLaren N, Ellis R, Bartie KL, Feist SW, Rowe WMP, Adams A, Thompson KD. Detection of the florfenicol resistance gene floR in Chryseobacterium isolates from rainbow trout. Exception to the general rule? FEMS Microbiol Ecol 2017; 93:2982884. [DOI: 10.1093/femsec/fix015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 02/08/2017] [Indexed: 11/15/2022] Open
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14
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Bayliss SC, Verner-Jeffreys DW, Bartie KL, Aanensen DM, Sheppard SK, Adams A, Feil EJ. The Promise of Whole Genome Pathogen Sequencing for the Molecular Epidemiology of Emerging Aquaculture Pathogens. Front Microbiol 2017; 8:121. [PMID: 28217117 PMCID: PMC5290457 DOI: 10.3389/fmicb.2017.00121] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/17/2017] [Indexed: 01/23/2023] Open
Abstract
Aquaculture is the fastest growing food-producing sector, and the sustainability of this industry is critical both for global food security and economic welfare. The management of infectious disease represents a key challenge. Here, we discuss the opportunities afforded by whole genome sequencing of bacterial and viral pathogens of aquaculture to mitigate disease emergence and spread. We outline, by way of comparison, how sequencing technology is transforming the molecular epidemiology of pathogens of public health importance, emphasizing the importance of community-oriented databases and analysis tools.
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Affiliation(s)
- Sion C Bayliss
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath Bath, UK
| | | | - Kerry L Bartie
- Institute of Aquaculture, University of Stirling Stirling, UK
| | - David M Aanensen
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College LondonLondon, UK; The Centre for Genomic Pathogen Surveillance, Wellcome Genome CampusCambridge, UK
| | - Samuel K Sheppard
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath Bath, UK
| | - Alexandra Adams
- Institute of Aquaculture, University of Stirling Stirling, UK
| | - Edward J Feil
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath Bath, UK
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15
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Henríquez P, Bohle H, Bustamante F, Bustos P, Mancilla M. Polymorphism in gyrA is associated to quinolones resistance in Chilean Piscirickettsia salmonis field isolates. JOURNAL OF FISH DISEASES 2015; 38:415-8. [PMID: 24917068 DOI: 10.1111/jfd.12255] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/07/2014] [Accepted: 04/14/2014] [Indexed: 05/12/2023]
Affiliation(s)
- P Henríquez
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
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16
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Huang GL, Huang ZS. Levofloxacin for Helicobacter pylori infection: Drug resistance and safety. Shijie Huaren Xiaohua Zazhi 2014; 22:4301-4305. [DOI: 10.11569/wcjd.v22.i28.4301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) is an important cause of chronic gastritis and peptic ulcer, closely correlates with mucosa-associated lymphoid tissue (MALT), and is a risk factor for gastric cancer. The constantly increasing rate of resistance of H. pylori to antibiotics is the main reason for failure of H. pylori eradication therapy. How to increase the H. pylori eradication rate has become the focus of current research. Current concepts in treatment of H. pylori infection, including the Maastricht Ⅲ consensus report and Chinese consensus report in recent years, have recommended levofloxacin as a first-line or remedial therapy, and good therapeutic effects have been achieved; however, the wide use of levofloxacin has led to an increase in drug resistant strains of H. pylori. Investigation of the mechanism behind levofloxacin resistance and the security of levofloxacin has important significance to guide the clinical medication. This paper reviews the role and mechanisms of levofloxacin in H. pylori eradication, levofloxacin resistance and related molecular mechanisms, and safety of levofloxacin in the management of H. pylori infection.
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17
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Multilocus sequence typing identifies epidemic clones of Flavobacterium psychrophilum in Nordic countries. Appl Environ Microbiol 2014; 80:2728-36. [PMID: 24561585 DOI: 10.1128/aem.04233-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacterium psychrophilum is the causative agent of bacterial cold water disease (BCWD), which affects a variety of freshwater-reared salmonid species. A large-scale study was performed to investigate the genetic diversity of F. psychrophilum in the four Nordic countries: Denmark, Finland, Norway, and Sweden. Multilocus sequence typing of 560 geographically and temporally disparate F. psychrophilum isolates collected from various sources between 1983 and 2012 revealed 81 different sequence types (STs) belonging to 12 clonal complexes (CCs) and 30 singleton STs. The largest CC, CC-ST10, which represented almost exclusively isolates from rainbow trout and included the most predominant genotype, ST2, comprised 65% of all isolates examined. In Norway, with a shorter history (<10 years) of BCWD in rainbow trout, ST2 was the only isolated CC-ST10 genotype, suggesting a recent introduction of an epidemic clone. The study identified five additional CCs shared between countries and five country-specific CCs, some with apparent host specificity. Almost 80% of the singleton STs were isolated from non-rainbow trout species or the environment. The present study reveals a simultaneous presence of genetically distinct CCs in the Nordic countries and points out specific F. psychrophilum STs posing a threat to the salmonid production. The study provides a significant contribution toward mapping the genetic diversity of F. psychrophilum globally and support for the existence of an epidemic population structure where recombination is a significant driver in F. psychrophilum evolution. Evidence indicating dissemination of a putatively virulent clonal complex (CC-ST10) with commercial movement of fish or fish products is strengthened.
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18
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Abstract
Helicobacter pylori (H. pylori) has been identified as the most important risk factor for chronic active gastritis and peptic ulcer disease. Resistance to antibiotics is increasing in H. pylori and is the main reason for failure of H. pylori eradication therapy. It is now widely accepted that resistance to fluoroquinolones (levofloxacin) is related with mutations of H. pylori gyrA gene. Molecular mechanisms of and detection methods for H. pylori resistance to levofloxacin have become the focus of current research. Therefore, study on H. pylori resistance to antibiotics is of great significance for eradication therapy of H. pylori infection.
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19
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Miranda CD, Tello A, Keen PL. Mechanisms of antimicrobial resistance in finfish aquaculture environments. Front Microbiol 2013; 4:233. [PMID: 23986749 PMCID: PMC3749489 DOI: 10.3389/fmicb.2013.00233] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/29/2013] [Indexed: 11/13/2022] Open
Abstract
Consumer demand for affordable fish drives the ever-growing global aquaculture industry. The intensification and expansion of culture conditions in the production of several finfish species has been coupled with an increase in bacterial fish disease and the need for treatment with antimicrobials. Understanding the molecular mechanisms of antimicrobial resistance prevalent in aquaculture environments is important to design effective disease treatment strategies, to prioritize the use and registration of antimicrobials for aquaculture use, and to assess and minimize potential risks to public health. In this brief article we provide an overview of the molecular mechanisms of antimicrobial resistance in genes found in finfish aquaculture environments and highlight specific research that should provide the basis of sound, science-based policies for the use of antimicrobials in aquaculture.
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Affiliation(s)
- Claudio D Miranda
- Department of Aquaculture, Universidad Católica del Norte Coquimbo, Chile
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20
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Cabello FC, Godfrey HP, Tomova A, Ivanova L, Dölz H, Millanao A, Buschmann AH. Antimicrobial use in aquaculture re-examined: its relevance to antimicrobial resistance and to animal and human health. Environ Microbiol 2013; 15:1917-42. [PMID: 23711078 DOI: 10.1111/1462-2920.12134] [Citation(s) in RCA: 387] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/10/2013] [Accepted: 02/14/2013] [Indexed: 12/18/2022]
Abstract
The worldwide growth of aquaculture has been accompanied by a rapid increase in therapeutic and prophylactic usage of antimicrobials including those important in human therapeutics. Approximately 80% of antimicrobials used in aquaculture enter the environment with their activity intact where they select for bacteria whose resistance arises from mutations or more importantly, from mobile genetic elements containing multiple resistance determinants transmissible to other bacteria. Such selection alters biodiversity in aquatic environments and the normal flora of fish and shellfish. The commonality of the mobilome (the total of all mobile genetic elements in a genome) between aquatic and terrestrial bacteria together with the presence of residual antimicrobials, biofilms, and high concentrations of bacteriophages where the aquatic environment may also be contaminated with pathogens of human and animal origin can stimulate exchange of genetic information between aquatic and terrestrial bacteria. Several recently found genetic elements and resistance determinants for quinolones, tetracyclines, and β-lactamases are shared between aquatic bacteria, fish pathogens, and human pathogens, and appear to have originated in aquatic bacteria. Excessive use of antimicrobials in aquaculture can thus potentially negatively impact animal and human health as well as the aquatic environment and should be better assessed and regulated.
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Affiliation(s)
- Felipe C Cabello
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, 10595, USA.
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21
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Sundell K, Heinikainen S, Wiklund T. Structure of Flavobacterium psychrophilum populations infecting farmed rainbow trout Oncorhynchus mykiss . DISEASES OF AQUATIC ORGANISMS 2013; 103:111-119. [PMID: 23548361 DOI: 10.3354/dao02573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Flavobacterium psychrophilum isolated from rainbow trout Oncorhynchus mykiss suffering from bacterial cold-water disease (BCWD) can dissociate into 2 morphological colony types, rough (R) and smooth (S). However, the presence of the 2 morphotypes in disease outbreaks has not yet been investigated thoroughly. We examined the occurrence of R and S morphotypes in rainbow trout from BCWD outbreaks and in unfertilized eggs from a hatchery. The isolated colony types were characterized by pulsed field gel electrophoresis (PFGE), plasmid analysis, and oxolinic acid susceptibility testing. From most outbreaks, both morphotypes were isolated, although the S type only was isolated from the majority of individual fish. PFGE analysis showed both diverse and indistinguishable genetic patterns among the concurrent morphotypes. While PFGE patterns common to both fish and egg isolates were identified, this was not always the case. Resistant and sensitive isolates of both colony types were isolated from individual disease outbreaks. The plasmid pattern was partly associated with the colony type, showing identical or completely different patterns for the R and S types isolated from the same outbreak. The study showed that within a BCWD outbreak, F. psychrophilum cells with different morphology, plasmid content, antibiotic susceptibility, and PFGE pattern can be isolated, suggesting that F. psychrophilum populations infecting rainbow trout in farm environments can be diverse and thus complicate the control of the disease.
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22
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Apablaza P, Løland AD, Brevik ØJ, Ilardi P, Battaglia J, Nylund A. Genetic variation among Flavobacterium psychrophilum isolates from wild and farmed salmonids in Norway and Chile. J Appl Microbiol 2013; 114:934-46. [PMID: 23289591 DOI: 10.1111/jam.12121] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/19/2012] [Accepted: 12/21/2012] [Indexed: 11/28/2022]
Abstract
AIMS To aim of the study was to describe the genetic relationship between isolates of Flavobacterium psychrophilum with a main emphasis of samples from Chile and Norway. The isolates have been obtained from farmed salmonids in Norway and Chile, and from wild salmonids in Norway, but isolates from North America and European countries are also included in the analysis. METHODS AND RESULTS The study is based on phylogenetic analysis of 16S rRNA and seven housekeeping genes (HG), gyrB, atpA, dnaK, trpB, fumC, murG and tuf, and the use of a multilocus sequence typing (MLST) system, based on nucleotide polymorphism in the HG, as an alternative to the phylogenies. The variation within the selected genes was limited, and the phylogenetic analysis gave little resolution between the isolates. The MLST gave a much better resolution resulting in 53 sequence types where the same sequences types could be found in Chile, North America and European countries, and in different host species. CONCLUSIONS Multilocus sequence typing give a relatively good separation of different isolates of Fl. psychrophilum and show that there are no distinct geographical or host-specific isolates in the studied material from Chile, North America and Europe. Nor was it possible to separate between isolates from ulcers and systemic infections vs isolates from the surface of healthy salmonids. SIGNIFICANCE AND IMPACT OF THE STUDY This study shows a wide geographical distribution of Fl. psychrophilum, indicating that the bacterium has a large potential for transmission over long distances, and between different salmonid hosts species. This knowledge will be important for future management of salmonids diseases connected to Fl. psychrophilum.
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Affiliation(s)
- P Apablaza
- Fish Diseases Research Group, Department of Biology, University of Bergen, Bergen, Norway.
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23
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Boulund F, Johnning A, Pereira MB, Larsson DGJ, Kristiansson E. A novel method to discover fluoroquinolone antibiotic resistance (qnr) genes in fragmented nucleotide sequences. BMC Genomics 2012; 13:695. [PMID: 23231464 PMCID: PMC3543242 DOI: 10.1186/1471-2164-13-695] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 12/04/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Broad-spectrum fluoroquinolone antibiotics are central in modern health care and are used to treat and prevent a wide range of bacterial infections. The recently discovered qnr genes provide a mechanism of resistance with the potential to rapidly spread between bacteria using horizontal gene transfer. As for many antibiotic resistance genes present in pathogens today, qnr genes are hypothesized to originate from environmental bacteria. The vast amount of data generated by shotgun metagenomics can therefore be used to explore the diversity of qnr genes in more detail. RESULTS In this paper we describe a new method to identify qnr genes in nucleotide sequence data. We show, using cross-validation, that the method has a high statistical power of correctly classifying sequences from novel classes of qnr genes, even for fragments as short as 100 nucleotides. Based on sequences from public repositories, the method was able to identify all previously reported plasmid-mediated qnr genes. In addition, several fragments from novel putative qnr genes were identified in metagenomes. The method was also able to annotate 39 chromosomal variants of which 11 have previously not been reported in literature. CONCLUSIONS The method described in this paper significantly improves the sensitivity and specificity of identification and annotation of qnr genes in nucleotide sequence data. The predicted novel putative qnr genes in the metagenomic data support the hypothesis of a large and uncharacterized diversity within this family of resistance genes in environmental bacterial communities. An implementation of the method is freely available at http://bioinformatics.math.chalmers.se/qnr/.
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Affiliation(s)
- Fredrik Boulund
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Göteborg, SE-412 96, Sweden
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24
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Shah SQA, Colquhoun DJ, Nikuli HL, Sørum H. Prevalence of antibiotic resistance genes in the bacterial flora of integrated fish farming environments of Pakistan and Tanzania. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:8672-8679. [PMID: 22823142 DOI: 10.1021/es3018607] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The use of a wide variety of antimicrobials in human and veterinary medicine, including aquaculture, has led to the emergence of antibiotic resistant pathogens. In the present study, bacteria from water, sediments, and fish were collected from fish farms in Pakistan and Tanzania with no recorded history of antibiotic use. The isolates were screened for the presence of resistance genes against various antimicrobials used in aquaculture and animal husbandry. Resistant isolates selected by disk diffusion and genotyped by Southern hybridization were further screened by polymerase chain reaction (PCR) and amplicon sequencing. The prominent resistance genes identified encoded tetracycline [tetA(A) and tetA(G)], trimethoprim [dfrA1, dfrA5, dfrA7, dfrA12, and dfrA15], amoxicillin [bla(TEM)], streptomycin [strA-strB], chloramphenicol [cat-1], and erythromycin resistance [mefA]. The int1 gene was found in more than 30% of the bacterial isolates in association with gene cassettes. MAR indices ranged from 0.2 to 1. The bla(NDM-1) gene was not identified in ertapenem resistant isolates. It is hypothesized that integrated fish farming practices utilizing domestic farm and poultry waste along with antibiotic residues from animal husbandry may have contributed to a pool of resistance genes in the aquaculture systems studied.
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Affiliation(s)
- Syed Q A Shah
- Department of Food Safety & Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, Oslo N-0033, Norway.
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