1
|
Ahmed AK, Sijercic VC, Akhtar MS, Elbayomy A, Marouf MA, Zeleke MS, Sayad R, Abdelshafi A, Laird NJ, El‐Mokhtar MA, Ruthig GR, Hetta HF. Cholera rages in Africa and the Middle East: A narrative review on challenges and solutions. Health Sci Rep 2024; 7:e2013. [PMID: 38742091 PMCID: PMC11089255 DOI: 10.1002/hsr2.2013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/27/2024] [Accepted: 03/12/2024] [Indexed: 05/16/2024] Open
Abstract
Background and Aim Cholera is a life-threatening infectious disease that is still one of the most common acute watery diarrheal diseases in the world today. Acute diarrhea and severe dehydration brought on by cholera can cause hypovolemic shock, which can be fatal in minutes. Without competent clinical therapy, the rate of case fatality surpasses 50%. The purpose of this review was to highlight cholera challenges in Africa and the Middle East and explain the reasons for why this region is currently a fertile environment for cholera. We investigated cholera serology, epidemiology, and the geographical distribution of cholera in Africa and the Middle East in 2022 and 2023. We reviewed detection methods, such as rapid diagnostic tests (RDTs), and treatments, such as antibiotics and phage therapy. Finally, this review explored oral cholera vaccines (OCVs), and the vaccine shortage crisis. Methods We carried out a systematic search in multiple databases, including PubMed, Web of Science, Google Scholar, Scopus, MEDLINE, and Embase, for studies on cholera using the following keywords: ((Cholera) OR (Vibrio cholera) and (Coronavirus) OR (COVID-19) OR (SARS-CoV2) OR (The Middle East) OR (Africa)). Results and Conclusions Cholera outbreaks have increased dramatically, mainly in Africa and many Middle Eastern countries. The COVID-19 pandemic has reduced the attention devoted to cholera and disrupted diagnosis and treatment services, as well as vaccination initiatives. Most of the cholera cases in Africa and the Middle East were reported in Malawi and Syria, respectively, in 2022. RDTs are effective in the early detection of cholera epidemics, especially with limited advanced resources, which is the case in much of Africa. By offering both direct and indirect protection, expanding the use of OCV will significantly reduce the burden of current cholera outbreaks in Africa and the Middle East.
Collapse
Affiliation(s)
| | | | | | - Ahmed Elbayomy
- Faculty of MedicineMansoura UniversityMansouraEgypt
- School of Medicine and Public HealthUniversity of Wisconsin−MadisonMadisonWisconsinUSA
| | - Mohamed A. Marouf
- Faculty of MedicineMansoura UniversityMansouraEgypt
- Department of Internal Medicine, Morsani College of MedicineUniversity of South FloridaTampaFloridaUSA
| | - Mahlet S. Zeleke
- Menelik II Medical and Health Science CollegeKotebe Metropolitan UniversityAddis AbabaEthiopia
| | - Reem Sayad
- Faculty of MedicineAssiut UniversityAssiutEgypt
| | | | | | - Mohamed A. El‐Mokhtar
- Gilbert & Rose‐Marie Chagoury School of MedicineLebanese American UniversityByblosLebanon
| | | | - Helal F. Hetta
- Division of Microbiology and Immunology, Department of Natural Products and Alternative Medicine, Faculty of PharmacyUniversity of TabukTabukSaudi Arabia
| |
Collapse
|
2
|
Jalalizadeh F, Njamkepo E, Weill FX, Goodarzi F, Rahnamaye-Farzami M, Sabourian R, Bakhshi B. Genetic approach toward linkage of Iran 2012-2016 cholera outbreaks with 7th pandemic Vibrio cholerae. BMC Microbiol 2024; 24:33. [PMID: 38254012 PMCID: PMC10801964 DOI: 10.1186/s12866-024-03185-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Vibrio cholerae, as a natural inhabitant of the marine environment is among the world-leading causes of diarrheal diseases. The present study aimed to investigate the genetic relatedness of Iran 2012-2016 V. cholerae outbreaks with 7th pandemic cholera and to further characterize the non-ST69/non-ST75 sequence types strains by whole-genome sequencing (WGS).Twenty V. cholerae isolates related to 2012, 2013, 2015 and 2016 cholera outbreaks were studied by two genotyping methods - Pulsed-field Gel Electrophoresis (PFGE) and Multi-locus Sequence Typing (MLST)-and by antimicrobial susceptibility testing. Seven sequence types (STs) and sixteen pulsotypes were detected. Sequence type 69 was the most abundant ST confirming that most (65%, 13/20) of the studied isolates collected in Iran between 2012 and 2016 belonged to the 7th pandemic clone. All these ST69 isolates (except two) exhibited similar pulsotypes. ST75 was the second most abundant ST. It was identified in 2015 and 2016. ST438, ST178, ST579 and STs of 983 and 984 (as newfound STs) each were only detected in one isolate. All strains collected in 2016 appeared as distinct STs and pulsotypes indicative of probable different originations. All ST69 strains were resistant to nalidixic acid. Moreover, resistance to nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline was only observed in strains of ST69. These properties propose the ST69 as a unique genotype derived from a separate lineage with distinct resistance properties. The circulation of V. cholerae ST69 and its traits in recent years in Iran proposes the 7th pandemic strains as the ongoing causes of cholera outbreaks in this country, although the role of ST75 as the probable upcoming dominant ST should not be ignored.Genomic analysis of non-ST69/non-ST75 strains in this study showed ST579 is the most similar ST type to 7th pandemic sequence types, due to the presence of wild type-El Tor sequences of tcpA and VC-1319, VC-1320, VC-1577, VC-1578 genes (responsible for polymyxin resistance in El Tor biotype), the traits of rstC of RS1 phage in one strain of this ST type and the presence of VPI-1 and VSP-I islands in ST579 and ST178 strains. In silico analysis showed no significant presence of resistance genes/cassettes/plasmids within non-ST69/non-ST75 strains genomes. Overall, these data indicate the higher susceptibility of V. cholerae non-ST69/non-ST75 strains in comparison with more ubiquitous and more circulating ST69 and ST75 strains.In conclusion, the occurrence of small outbreaks and sporadic cholera cases due to V. cholerae ST69 in recent years in Iran shows the 7th pandemic strains as the persistent causes of cholera outbreaks in this country, although the role of ST75 as the second most contributed ST should not be ignored. The occurrence of non-ST69/non-ST75 sequence types with some virulence factors characteristics in border provinces in recent years is noteworthy, and further studies together with surveillance efforts are expected to determine their likely route of transport.
Collapse
Affiliation(s)
- Fatemeh Jalalizadeh
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | | | - Forough Goodarzi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | | | - Bita Bakhshi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| |
Collapse
|
3
|
Opintan JA, Will RC, Kuma GK, Osei M, Akumwena A, Boateng G, Owusu-Okyere G, Antwi L, Opare D, Pragasam AK, Vasudevan K, Srivastava SK, Balaji V, Newman MJ, Dougan G, Mutreja A. Phylogenetic and antimicrobial drug resistance analysis of Vibrio cholerae O1 isolates from Ghana. Microb Genom 2021; 7. [PMID: 34714228 PMCID: PMC8627208 DOI: 10.1099/mgen.0.000668] [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] [Indexed: 11/18/2022] Open
Abstract
We investigated the evolution, phylogeny and antimicrobial resistance of Vibrio cholerae O1 isolates (VCO1) from Ghana. Outbreak and environmental sources of VCO1 were characterized, whole-genome sequenced and compared to globally available seventh pandemic (7P) strains of V. cholerae at SNP resolution. Final analyses included 636 isolates. Novel Ghanaian isolates clustered into three distinct clades (clades 1, 2 and 3) in wave 3 of the 7P lineage. The closest relatives of our novel Ghanaian isolates were from Benin, Cameroon, Togo, Niger and Nigeria. All novel Ghanaian isolates were multi-drug resistant. Environmental isolates clustered into clade 2, despite being isolated years later, showing the possibility of persistence and re-emergence of older clades. A lag phase of several years from estimated introduction to reported cases suggests pathogen persistence in the absence of reported cholera cases. These results highlight the importance of deeper surveillance for understanding transmission routes between bordering countries and planning tailored vaccination campaigns in an effort to eradicate cholera.
Collapse
Affiliation(s)
- Japheth A Opintan
- Medical Microbiology Department, University of Ghana Medical School, Accra, Ghana.,Department of Medicine, University of Cambridge, Cambridge, UK
| | - Robert C Will
- Department of Medicine, University of Cambridge, Cambridge, UK.,Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - George K Kuma
- Laboratory Department, Brong Ahafo Regional Hospital, Sunyani, Ghana
| | - Mary Osei
- Medical Microbiology Department, University of Ghana Medical School, Accra, Ghana
| | - Amos Akumwena
- Medical Microbiology Department, University of Ghana Medical School, Accra, Ghana
| | - Gifty Boateng
- National Public Health Reference Laboratory, Accra, Ghana
| | | | - Lorreta Antwi
- National Public Health Reference Laboratory, Accra, Ghana
| | - David Opare
- National Public Health Reference Laboratory, Accra, Ghana
| | | | - Karthick Vasudevan
- Christian Medical College, Vellore, Tamil Nadu, India.,Department of Biotechnology, School of Applied Sciences, REVA University, Bangalore, India
| | | | | | - Mercy J Newman
- Medical Microbiology Department, University of Ghana Medical School, Accra, Ghana
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK.,Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - Ankur Mutreja
- Department of Medicine, University of Cambridge, Cambridge, UK.,Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK.,Translational Health Science and Technology Institute, Faridabad, India
| |
Collapse
|
4
|
Chen YS, Tu YH, Chen BH, Liu YY, Hong YP, Teng RH, Wang YW, Chiou CS. cgMLST@Taiwan: A web service platform for Vibrio cholerae cgMLST profiling and global strain tracking. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2021; 55:102-106. [PMID: 33485793 DOI: 10.1016/j.jmii.2020.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Cholera, a rapidly dehydrating diarrheal disease caused by toxigenic Vibrio cholerae, is a leading cause of morbidity and mortality in some regions of the world. Core genome multilocus sequence typing (cgMLST) is a promising approach in generating genetic fingerprints from whole-genome sequencing (WGS) data for strain comparison among laboratories. METHODS We constructed a V. cholerae core gene allele database using an in-house developed computational pipeline, a database with cgMLST profiles converted from genomic sequences from the National Center for Biotechnology Information, and built a REST-based web accessible via the Internet. RESULTS We built a web service platform-cgMLST@Taiwan and installed a V. cholerae allele database, a cgMLST profile database, and computational tools for generating V. cholerae cgMLST profiles (based on 3,017 core genes), performing rapid global strain tracking, and clustering analysis of cgMLST profiles. This web-based platform provides services to researchers, public health microbiologists, and physicians who use WGS data for the investigation of cholera outbreaks and tracking of V. cholerae strain transmission across countries and geographic regions. The cgMLST@Taiwan is accessible at http://rdvd.cdc.gov.tw/cgMLST.
Collapse
Affiliation(s)
- Yi-Syong Chen
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Yueh-Hua Tu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Bo-Han Chen
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Yen-Yi Liu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Yu-Ping Hong
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Ru-Hsiou Teng
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - You-Wun Wang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan
| | - Chien-Shun Chiou
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taiwan.
| |
Collapse
|
5
|
Characterization of multidrug resistance in Vibrio species isolated from marine invertebrates from Andaman Sea. 3 Biotech 2020; 10:456. [PMID: 33088653 DOI: 10.1007/s13205-020-02445-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/18/2020] [Indexed: 10/23/2022] Open
Abstract
This study describes the abundance of multidrug-resistant Vibrios associated with marine invertebrate hosts from the Andaman Sea, India. Thirty-eight Vibrio strains were isolated from surface mucus layers of coral Porites, Goniastrea, Pocillopora, Fungia, and eggs of spiny lobster (Panulirus penicillatus). Phenotypically, the majority of strains exhibited growth at a wide range of temperatures, salt tolerance, and diverse nutritional requirements. All the strains had more than 97% 16S rRNA sequence similarity with type species of the genus Vibrio where Vibrio fortis, and Vibrio alginolyticus were predominant. Multilocus Sequence Analysis (MLSA) using eight housekeeping genes namely ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA, and topA distributed the strains into 6 reported clades i.e., Harveyi, Ponticus, Nereis, Orientalis, Splendidus, and Mediterranei where nearly half of the total strains represented the clade Harveyi, followed by the clade Splendidus. Likewise, the PFGE profile indicated genomic heterogeneity among the strains resulting in their distribution in five major clusters. Resistance to different antimicrobials was tested following the disc diffusion method where all strains were found susceptible to chloramphenicol (30 µg) and resistant to streptomycin (10 µg), vancomycin (30 µg), sulfamethoxazole-trimethoprim (25 µg). Moreover, the resistant phenotype to other antimicrobials confirmed the abundance of multidrug resistance strains in this marine environment.
Collapse
|
6
|
Kanampalliwar A, Singh DV. Virulence Pattern and Genomic Diversity of Vibrio cholerae O1 and O139 Strains Isolated From Clinical and Environmental Sources in India. Front Microbiol 2020; 11:1838. [PMID: 32982995 PMCID: PMC7479179 DOI: 10.3389/fmicb.2020.01838] [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: 02/02/2020] [Accepted: 07/14/2020] [Indexed: 01/22/2023] Open
Abstract
Vibrio cholerae is an autochthonous inhabitant of the aquatic environment. Several molecular methods have been used for typing V. cholerae strains, but there is no proper database for such scheme, including multilocus sequence typing (MLST) for V. cholerae O1 and O139 strains. We used 54 V. cholerae O1 and three O139 strains isolated from clinical and environmental sources and regions of India during the time period of 1975-2015 to determine the presence of virulence genes and production of biofilm. We devised a MLST scheme and developed a database for typing V. cholerae strains. Also, we performed pulsed-field gel electrophoresis to see the genomic diversity among them and compared it with MLST. We used the MEGA 7.0 software for the alignment and comparison of different nucleotide sequences. The advanced cluster analysis was performed to define complexes. All strains of V. cholerae, except five strains, showed variation in phenotypic characteristics but carried virulence-associated genes indicating they belonged to the El Tor/hybrid/O139 variants. MLST analysis showed 455 sequences types among V. cholerae strains, irrespective of sources and places of isolation. With these findings, we set up an MLST database on PubMLST.org using the BIGSdb software for V. cholerae O1 and O139 strains, which is available at https://pubmlst.org/vcholerae/ under the O1/O139 scheme. The pulsed-field gel electrophoresis (PFGE) fingerprint showed six fingerprint patterns namely E, F, G, H, I, and J clusters among 33 strains including strain N16961 carrying El Tor ctxB of which cluster J representing O139 strain was entirely different from other El Tor strains. Twenty strains carrying Haitian ctxB showed a fingerprint pattern classified as cluster A. Of the five strains, four carrying classical ctxB comprising two each of El Tor and O139 strains and one El Tor strain carrying Haitian ctxB clustered together under cluster B along with V. cholerae 569B showing pattern D. This study thus indicates that V. cholerae strains are undergoing continuous genetic changes leading to the emergence of new strains. The MLST scheme was found more appropriate compared to PFGE that can be used to determine the genomic diversity and population structure of V. cholerae.
Collapse
Affiliation(s)
- Amol Kanampalliwar
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Durg Vijai Singh
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India.,Department of Biotechnology, School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Gaya, India
| |
Collapse
|
7
|
Bénard AHM, Guenou E, Fookes M, Ateudjieu J, Kasambara W, Siever M, Rebaudet S, Boncy J, Adrien P, Piarroux R, Sack DA, Thomson N, Debes AK. Whole genome sequence of Vibrio cholerae directly from dried spotted filter paper. PLoS Negl Trop Dis 2019; 13:e0007330. [PMID: 31145741 PMCID: PMC6559667 DOI: 10.1371/journal.pntd.0007330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 06/11/2019] [Accepted: 03/25/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Global estimates for cholera annually approximate 4 million cases worldwide with 95,000 deaths. Recent outbreaks, including Haiti and Yemen, are reminders that cholera is still a global health concern. Cholera outbreaks can rapidly induce high death tolls by overwhelming the capacity of health facilities, especially in remote areas or areas of civil unrest. Recent studies demonstrated that stool specimens preserved on filter paper facilitate molecular analysis of Vibrio cholerae in resource limited settings. Specimens preserved in a rapid, low-cost, safe and sustainable manner for sequencing provides previously unavailable data about circulating cholera strains. This may ultimately contribute new information to shape public policy response on cholera control and elimination. METHODOLOGY/PRINCIPAL FINDINGS Whole genome sequencing (WGS) recovered close to a complete sequence of the V. cholerae O1 genome with satisfactory genome coverage from stool specimens enriched in alkaline peptone water (APW) and V. cholerae culture isolates, both spotted on filter paper. The minimum concentration of V. cholerae DNA sufficient to produce quality genomic information was 0.02 ng/μL. The genomic data confirmed the presence or absence of genes of epidemiological interest, including cholera toxin and pilus loci. WGS identified a variety of diarrheal pathogens from APW-enriched specimen spotted filter paper, highlighting the potential for this technique to explore the gut microbiome, potentially identifying co-infections, which may impact the severity of disease. WGS demonstrated that these specimens fit within the current global cholera phylogenetic tree, identifying the strains as the 7th pandemic El Tor. CONCLUSIONS WGS results allowed for mapping of short reads from APW-enriched specimen and culture isolate spotted filter papers. This provided valuable molecular epidemiological sequence information on V. cholerae strains from remote, low-resource settings. These results identified the presence of co-infecting pathogens while providing rare insight into the specific V. cholerae strains causing outbreaks in cholera-endemic areas.
Collapse
Affiliation(s)
| | - Etienne Guenou
- M.A. SANTE (Meilleur Accès aux Soins de Santé), Yaoundé, Cameroon
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Maria Fookes
- Wellcome Trust Sanger Institute, Genome campus, Hinxton United Kingdom
| | - Jerome Ateudjieu
- M.A. SANTE (Meilleur Accès aux Soins de Santé), Yaoundé, Cameroon
- Department of Public Health, Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Cameroon Dschang Cameroon
- Clinical Research Unit, Division of Health Operations Research, Ministry of Public Health, N°8, quartier du Lac (Yaoundé III), Cameroon
| | | | - Matthew Siever
- John Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Stanislas Rebaudet
- Assistance Publique–Hôpitaux de Marseille (APHM), Marseille, France
- Hôpital Européen, Marseille, France
| | - Jacques Boncy
- National Laboratory of Public Health in Haiti (LNSP), Ministry of Public Health and Population, Haiti
| | - Paul Adrien
- Directorate for Epidemiology, Laboratory and Research, Ministry of Public Health and Population, Haiti
| | - Renaud Piarroux
- Sorbonne Université, INSERM, Institut Pierre-Louis d’Epidémiologie et de Santé Publique, APHP, Hôpital Pitié-Salpêtrière, Paris, France
| | - David A. Sack
- John Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Nicholas Thomson
- Wellcome Trust Sanger Institute, Genome campus, Hinxton United Kingdom
- London School of Hygiene and Tropical Medicine, Keppel St, Bloomsbury, London WC1E 7HT, United Kingdom
| | - Amanda K. Debes
- John Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| |
Collapse
|
8
|
Smith AM. Review of molecular subtyping methodologies used to investigate outbreaks due to multidrug-resistant enteric bacterial pathogens in sub-Saharan Africa. Afr J Lab Med 2019; 8:760. [PMID: 31205868 PMCID: PMC6556818 DOI: 10.4102/ajlm.v8i1.760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 09/25/2018] [Indexed: 01/05/2023] Open
Abstract
Background In sub-Saharan Africa, molecular epidemiological investigation of outbreaks caused by antimicrobial-resistant enteric bacterial pathogens have mostly been described for Salmonella species, Vibrio cholerae, Shigella species and Escherichia coli. For these organisms, I reviewed all publications describing the use of molecular subtyping methodologies to investigate outbreaks caused by multidrug-resistant (MDR) enteric bacterial infections. Objectives To describe the use of molecular subtyping methodologies to investigate outbreaks caused by MDR enteric bacterial pathogens in sub-Saharan Africa and to describe the current status of molecular subtyping capabilities in the region. Methods A PubMed database literature search (English language only) was performed using the search strings: ‘Africa outbreak MDR’, ‘Africa outbreak multi’, ‘Africa outbreak multidrug’, ‘Africa outbreak multi drug’, ‘Africa outbreak resistance’, ‘Africa outbreak resistant’, ‘Africa outbreak drug’, ‘Africa outbreak antibiotic’, ‘Africa outbreak antimicrobial’. These search strings were used in combination with genus and species names of the organisms listed above. All results were included in the review. Results The year 1991 saw one of the first reports describing the use of molecular subtyping methodologies in sub-Saharan Africa; this included the use of plasmid profiling to characterise Salmonella Enteritidis. To date, several methodologies have been used; pulsed-field gel electrophoresis analysis and multilocus sequence typing have been the most commonly used methodologies. Investigations have particularly highlighted the emergence and spread of MDR clones; these include Salmonella Typhi H58 and Salmonella Typhimurium ST313 clones. In recent times, whole-genome sequencing (WGS) analysis approaches have increasingly been used. Conclusion Traditional molecular subtyping methodologies are still commonly used and still have their place in investigations; however, WGS approaches have increasingly been used and are slowly gaining a stronghold. African laboratories need to start adapting their molecular surveillance methodologies to include WGS, as it is foreseen that WGS analysis will eventually replace all traditional methodologies.
Collapse
Affiliation(s)
- Anthony M Smith
- Centre for Enteric Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa.,Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| |
Collapse
|
9
|
Cholera: an overview with reference to the Yemen epidemic. Front Med 2018; 13:213-228. [DOI: 10.1007/s11684-018-0631-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/18/2017] [Indexed: 12/12/2022]
|
10
|
Learoyd TP, Gaut RM. Cholera: under diagnosis and differentiation from other diarrhoeal diseases. J Travel Med 2018; 25:S46-S51. [PMID: 29718439 DOI: 10.1093/jtm/tay017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/08/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Globally 1.4 billion people are at risk from cholera in countries where the disease is endemic, with an estimated 2.8 million cases annually. The disease is significantly under reported due to economic, social and political disincentives as well as poor laboratory resources and epidemiological surveillance in those regions. In addition, identification of cholera from other diarrhoeal causes is often difficult due to shared pathology and symptoms with few reported cases in travellers from Northern Europe. METHODS A search of PubMed and Ovid Medline for publications on cholera diagnosis from 2010 through 2017 was conducted. Search terms included were cholera, Rapid Diagnostic Test (RDT), multiplex PCR and diagnosis of diarrhoea. Studies were included if they are published in English, French or Spanish. RESULTS An increase of RDT study publications for diarrhoeal disease and attempted test validations were seen over the publication period. RDTs were noted as having varied selectivity and specificity, as well as associated costs and local resource requirements that can prohibit their use. CONCLUSIONS Despite opportunities to employ RDTs with high selectivity and specificity in epidemic areas, or in remote locations without access to health services, such tests are limited to surveillance use. This may represent a missed opportunity to discover the true global presence of Vibrio cholerae and its role in all cause diarrhoeal disease in underdeveloped countries and in travellers to those areas. The wider applicability of RDTs may also represent an opportunity in the wider management of traveller's diarrhoea.
Collapse
Affiliation(s)
- Tristan P Learoyd
- Valneva UK, Centaur House, Ancells Business Park, Ancells Road, Fleet, Hampshire GU51 2UJ, UK
| | - Rupert M Gaut
- Xnomics Ltd, Yarm Road, Eaglescliffe, Stockton-on-Tees TS16 9BJ, UK
| |
Collapse
|
11
|
Mironova LV, Gladkikh AS, Ponomareva AS, Feranchuk SI, Bochalgin NО, Basov EA, Yu Khunkheeva Z, Balakhonov SV. Comparative genomics of Vibrio cholerae El Tor strains isolated at epidemic complications in Siberia and at the Far East. INFECTION GENETICS AND EVOLUTION 2018; 60:80-88. [PMID: 29462719 DOI: 10.1016/j.meegid.2018.02.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 11/30/2022]
Abstract
The territory of Siberia and the Far East of Russia is classified as epidemically safe for cholera; however, in the 1970s and 1990s a number of infection importation cases and acute outbreaks associated with the cholera importation were reported. Here, we analyze genomes of four Vibrio cholerae El Tor strains isolated from humans during epidemic complications (imported cases, an outbreak) in the 1990s. The analyzed strains harbor the classical allele of the cholera toxin subunit B gene (ctxB1); thus, belong to genetically altered variants of the El Tor biotype. Analysis of the genomes revealed their high homology with the V. cholerae N16961 reference strain: 85-93 SNPs were identified in the core genome as compared to the reference. The determined features of SNPs in the CTX prophage made it possible to propose the presence of a new subtype - CTX-2a in two strains; the other two strains carried the prophage of CTX-3 type. Results of phylogenetic analysis based on SNP-typing demonstrated that two strains belonged to the second wave, and two - to the early third wave of cholera dissemination in the world. Phylogenetic reconstruction in combination with epidemiological data permitted to trace the origin of the strains and the way of their importation to the Russian Federation directly or through temporary cholera foci.
Collapse
Affiliation(s)
- Liliya V Mironova
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| | - Anna S Gladkikh
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia.
| | - Anna S Ponomareva
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| | - Sergey I Feranchuk
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia; Limnological Institute of Siberian Branch of Russian Academy of Sciences, 3, Ulan-Batorskaya str., Irkutsk 664033, Russia
| | - Nikita О Bochalgin
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| | - Evgenii A Basov
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| | - Zhanna Yu Khunkheeva
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| | - Sergey V Balakhonov
- Irkutsk Antiplague Research Institute of Rospotrebnadzor, 78, Trillisser str., Irkutsk 664047, Russia
| |
Collapse
|
12
|
Vibrio cholerae embraces two major evolutionary traits as revealed by targeted gene sequencing. Sci Rep 2018; 8:1631. [PMID: 29374205 PMCID: PMC5785995 DOI: 10.1038/s41598-018-19995-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/11/2018] [Indexed: 01/27/2023] Open
Abstract
Vibrio cholerae inhabits aquatic environments worldwide and has over 200 recognized serogroups classified by O-polysaccharide specificity. Here, we report that V. cholerae selects either of two genetic traits during their evolution. Sequencing of the specific gene locus MS6_A0927 revealed that 339 of 341 strains of V. cholerae and closely related Vibrio species originating from 34 countries over a century carried either metY (M) (~1,269 bp) or luxR-hchA (LH) (~1,600 bp) genes, and consequently those vibrios were separated into two clusters, M (45.4%) and LH (54.6%). Only two strains contained both M and LH in the same locus. Moreover, extensive polymorphisms in those genes were detected in M and LH with 79 and 46 sequence variations, respectively. V. cholerae O1 strains isolated from cholera outbreaks worldwide, and some non-O1 strains evolving from O1 via exchange of genes encoding cell surface polysaccharides possessed LH alleles. Analysis of polymorphisms in the gene locus implicated a high degree of genetic diversity and identical subpopulations among the V. cholerae species.
Collapse
|
13
|
Roobthaisong A, Okada K, Htun N, Aung WW, Wongboot W, Kamjumphol W, Han AA, Yi Y, Hamada S. Molecular Epidemiology of Cholera Outbreaks during the Rainy Season in Mandalay, Myanmar. Am J Trop Med Hyg 2017; 97:1323-1328. [PMID: 28820711 DOI: 10.4269/ajtmh.17-0296] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Cholera, caused by Vibrio cholerae, remains a global threat to public health. In Myanmar, the availability of published information on the occurrence of the disease is scarce. We report here that cholera incidence in Mandalay generally exhibited a single annual peak, with an annual average of 312 patients with severe dehydration over the past 5 years (since 2011) and was closely associated with the rainy season. We analyzed cholera outbreaks, characterized 67 isolates of V. cholerae serogroup O1 in 2015 from patients from Mandalay, and compared them with 22 V. cholerae O1 isolates (12 from Mandalay and 10 from Yangon) in 2014. The isolates carried the classical cholera toxin B subunit (ctxB), the toxin-coregulated pilus A (tcpA) of Haitian type, and repeat sequence transcriptional regulator (rstR) of El Tor type. Two molecular typing methods, pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analysis (MLVA), differentiated the 89 isolates into seven pulsotypes and 15 MLVA profiles. Pulsotype Y15 and one MLVA profile (11, 7, 7, 16, 7) were predominantly found in the isolates from cholera outbreaks in Mandalay, 2015. Pulsotypes Y11, Y12, and Y15 with some MLVA profiles were detected in the isolates from two remote areas, Mandalay and Yangon, with temporal changes. These data suggested that cholera spread from the seaside to the inland area in Myanmar.
Collapse
Affiliation(s)
- Amonrattana Roobthaisong
- Section of Bacterial Infections, Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand
| | - Kazuhisa Okada
- Section of Bacterial Infections, Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand.,Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Nilar Htun
- University of Medicine, Mandalay, Myanmar
| | - Wah Wah Aung
- Advanced Molecular Research Centre, Department of Medical Research, Yangon, Myanmar
| | - Warawan Wongboot
- Section of Bacterial Infections, Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand
| | - Watcharaporn Kamjumphol
- Section of Bacterial Infections, Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand
| | | | - Yi Yi
- Public Health Laboratory, Mandalay, Myanmar
| | - Shigeyuki Hamada
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| |
Collapse
|
14
|
Oh YT, Kim HY, Kim EJ, Go J, Hwang W, Kim HR, Kim DW, Yoon SS. Selective and Efficient Elimination of Vibrio cholerae with a Chemical Modulator that Targets Glucose Metabolism. Front Cell Infect Microbiol 2016; 6:156. [PMID: 27900286 PMCID: PMC5111416 DOI: 10.3389/fcimb.2016.00156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/02/2016] [Indexed: 12/16/2022] Open
Abstract
Vibrio cholerae, a Gram-negative bacterium, is the causative agent of pandemic cholera. Previous studies have shown that the survival of the seventh pandemic El Tor biotype V. cholerae strain N16961 requires production of acetoin in a glucose-rich environment. The production of acetoin, a neutral fermentation end-product, allows V. cholerae to metabolize glucose without a pH drop, which is mediated by the production of organic acid. This finding suggests that inhibition of acetoin fermentation can result in V. cholerae elimination by causing a pH imbalance under glucose-rich conditions. Here, we developed a simple high-throughput screening method and identified an inducer of medium acidification (iMAC). Of 8364 compounds screened, we identified one chemical, 5-(4-chloro-2-nitrobenzoyl)-6-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione, that successfully killed glucose-metabolizing N16961 by inducing acidic stress. When N16961 was grown with abundant glucose in the presence of iMAC, acetoin production was completely suppressed and concomitant accumulation of lactate and acetate was observed. Using a beta-galactosidase activity assay with a single-copy palsD::lacZ reporter fusion, we show that that iMAC likely inhibits acetoin production at the transcriptional level. Thin-layer chromatography revealed that iMAC causes a significantly reduced accumulation of intracellular (p)ppGpp, a bacterial stringent response alarmone known to positively regulate acetoin production. In vivo bacterial colonization and fluid accumulation were also markedly decreased after iMAC treatment. Finally, we demonstrate iMAC-induced bacterial killing for 22 different V. cholerae strains belonging to diverse serotypes. Together, our results suggest that iMAC, acting as a metabolic modulator, has strong potential as a novel antibacterial agent for treatment against cholera.
Collapse
Affiliation(s)
- Young Taek Oh
- Department of Microbiology and Immunology, Yonsei University College of Medicine Seoul, South Korea
| | - Hwa Young Kim
- Department of Microbiology and Immunology, Yonsei University College of MedicineSeoul, South Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of MedicineSeoul, South Korea
| | - Eun Jin Kim
- Department of Pharmacy, College of Pharmacy, Hanyang University Ansan, South Korea
| | - Junhyeok Go
- Department of Microbiology and Immunology, Yonsei University College of MedicineSeoul, South Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of MedicineSeoul, South Korea
| | - Wontae Hwang
- Department of Microbiology and Immunology, Yonsei University College of MedicineSeoul, South Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of MedicineSeoul, South Korea
| | - Hyoung Rae Kim
- Bio and Drug Discovery Division, Korea Research Institute of Chemical Technology Daejeon, South Korea
| | - Dong Wook Kim
- Department of Pharmacy, College of Pharmacy, Hanyang UniversityAnsan, South Korea; Institute of Pharmacological Research, Hanyang UniversityAnsan, South Korea
| | - Sang Sun Yoon
- Department of Microbiology and Immunology, Yonsei University College of MedicineSeoul, South Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of MedicineSeoul, South Korea; Institute for Immunology and Immunological Diseases, Yonsei University College of MedicineSeoul, South Korea
| |
Collapse
|
15
|
Oladokun MO, Okoh IA. Vibrio cholerae: A historical perspective and current trend. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2016. [DOI: 10.1016/s2222-1808(16)61154-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
16
|
Smirnova NI, Kul’shan’ TA, Baranikhina EY, Krasnov YM, Agafonov DA, Kutyrev VV. Genome structure and origin of nontoxigenic strains of Vibrio cholerae of El Tor biovar with different epidemiological significance. RUSS J GENET+ 2016. [DOI: 10.1134/s1022795416060120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
17
|
Ranjbar R, Sadeghy J, Shokri Moghadam M, Bakhshi B. Multi-locus variable number tandem repeat analysis of Vibrio cholerae isolates from 2012 to 2013 cholera outbreaks in Iran. Microb Pathog 2016; 97:84-8. [PMID: 27247094 DOI: 10.1016/j.micpath.2016.05.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/12/2016] [Accepted: 05/27/2016] [Indexed: 11/18/2022]
Abstract
Cholera remains to be an international threat, with high rates of illness and death. In 2012 and 2013, two cholera outbreak happened in Iran, affecting lots of people. Vibrio cholerae O1 was confirmed as the etiological agent. Source identification and controlling the spread of the cholera disease are two critical approaches in cholera outbreaks. In this study, thirty V. cholerae O1 isolates were selected and has been evaluated for antimicrobial resistant as well as molecular typing by multilocus variable-number tandem-repeat analysis (MLVA) method. Twenty-nine (97%) isolates were sero-grouped as El Tor (one isolate was classical) and 100% were related to Inaba serotype. All of the isolates were susceptible to ciprofloxacin, chloramphenicol, ampicillin and gentamicin. On the other hand, 60% of the isolates were MDR (resistant to 3 or more classes). There were three resistance patterns. The most prevalent pattern was resistance to streptomycin, erythromycin, trimethoprim-sulfamethoxazole, and tetracycline (ST-SXT-E-T) which was seen in 50% of isolates. Using MLVA method 14 MLVA types were identified. MLVA type 2 (5-7-7-16-15) accounted for 43% of isolates. Isolates with the same genotype often did not have the same antibiogram. Overall, the data indicate that the Iranian V. cholerae were MDR and clonaly related. Furthermore, the results of this study shows that MLVA can be used as useful method for V. cholerae genotyping in epidemiological investigations.
Collapse
Affiliation(s)
- R Ranjbar
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - J Sadeghy
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Iran
| | - M Shokri Moghadam
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Iran
| | - B Bakhshi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Iran.
| |
Collapse
|
18
|
Shpilevaya MV, Obraztsova OA, Chestkov AV. The use of current genotyping assay methods for Neisseria gonorrhoeae. VESTNIK DERMATOLOGII I VENEROLOGII 2015. [DOI: 10.25208/0042-4609-2015-91-6-33-40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The review deals with up-to-date genotyping assay methods of Neisseria gonorrhoeae. The review covers the characteristics and features of each method, application areas of genotyping assay of Neisseria gonorrhoeae. The methods described enable to upgrade the diagnostication of gonococcal infection, predict its antibiotic resistance, trace the contagion and channels of the infection as well as study the processes of molecular evolution of the microorganism. Information obtained based on up-to-date N. gonorrhoeae genotyping assay methods can be used in developing the reproductive health strategy of the population.
Collapse
|
19
|
Bartholomew JC, Pearson AD, Stenseth NC, LeDuc JW, Hirschberg DL, Colwell RR. Building Infectious Disease Research Programs to Promote Security and Enhance Collaborations with Countries of the Former Soviet Union. Front Public Health 2015; 3:271. [PMID: 26636067 PMCID: PMC4660230 DOI: 10.3389/fpubh.2015.00271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/12/2015] [Indexed: 01/25/2023] Open
Abstract
Addressing the threat of infectious diseases, whether natural, the results of a laboratory accident, or a deliberate act of bioterrorism, requires no corner of the world be ignored. The mobility of infectious agents and their rapid adaptability, whether to climate change or socioeconomic drivers or both, demand the science employed to understand these processes be advanced and tailored to a country or a region, but with a global vision. In many parts of the world, largely because of economic struggles, scientific capacity has not kept pace with the need to accomplish this goal and has left these regions and hence the world vulnerable to infectious disease outbreaks. To build scientific capability in a developing region requires cooperation and participation of experienced international scientists who understand the issues and are committed to educate the next generations of young investigators in the region. These efforts need to be coupled with the understanding and resolve of local governments and international agencies to promote an aggressive science agenda. International collaborative scientific investigation of infectious diseases not only adds significantly to scientific knowledge, but it promotes health security, international trust, and long-term economic benefit to the region involved. This premise is based on the observation that the most powerful human inspiration is that which brings peoples together to work on and solve important global challenges. The republics of the former Soviet Union provide a valuable case study for the need to rebuild scientific capacity as they are located at the crossroads where many of the world’s great epidemics began. The scientific infrastructure and disease surveillance capabilities of the region suffered significant decline after the breakup of the Soviet Union. The U.S. Cooperative Threat Reduction (CTR) Program, a part of the U.S. Department of Defense, together with partner countries, have worked diligently to improve the capabilities in this region to guard against the potential future risk from especially dangerous pathogens. The dissolution of the Soviet Union left behind many scientists still working to study pathogens using antiquated protocols in unsafe laboratories. To address this situation, the CTR program began improving laboratory infrastructure, establishing biosafety and biosecurity programs, and training scientists in modern techniques, with emphasis on biosurveillance and safe containment of especially dangerous pathogens. In the Republic of Georgia, this effort culminated in the construction of a modern containment laboratory, the Richard G. Lugar Center for Public Health Research in Tbilisi to house both isolated especially dangerous pathogens as well as the research to be conducted on these agents. The need now is to utilize and sustain the investment made by CTR by establishing strong public and animal health science programs in these facilities tailored to the needs of the region and the goals for which this investment was made. A similar effort is ongoing in other former Soviet Republics. Here, we provide the analysis and recommendations of an international panel of expert scientists appointed by the Cooperative Biological Engagement Program of the Defense Threat Reduction Agency to provide advice to the stakeholders on the scientific path for the future. The emphasis is on an implementation strategy for decision makers and scientists to consider providing a sustainable biological science program in support of the One Health initiative. Opportunities, potential barriers, and lessons learned while meeting the needs of the Republic of Georgia and the Caucasus region are discussed. It is hoped that this effort will serve as a model for similar scientific needs in not only the former Soviet Union republics but also other regions challenged by infectious diseases where the CTR program operates.
Collapse
Affiliation(s)
- James C. Bartholomew
- Lawrence Berkeley National Laboratory, University of California Berkeley, Berkeley, CA, USA
- *Correspondence: James C. Bartholomew,
| | - Andrew D. Pearson
- Center for Bioinformatics and Computational Biology, University of Maryland Center for Advanced Computer Studies, University of Maryland, College Park, MD, USA
| | - Nils Chr. Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - James W. LeDuc
- Galveston National Laboratory, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - David L. Hirschberg
- Department of Interdisciplinary Arts and Sciences, University of Washington Tacoma, Washington, DC, USA
| | - Rita R. Colwell
- Center for Bioinformatics and Computational Biology, University of Maryland Center for Advanced Computer Studies, University of Maryland, College Park, MD, USA
| |
Collapse
|