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Prygiel M, Mosiej E, Polak M, Krysztopa-Grzybowska K, Wdowiak K, Formińska K, Zasada AA. Challenges of Diphtheria Toxin Detection. Toxins (Basel) 2024; 16:245. [PMID: 38922140 PMCID: PMC11209151 DOI: 10.3390/toxins16060245] [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: 04/25/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/27/2024] Open
Abstract
Diphtheria toxin (DT) is the main virulence factor of Corynebacterium diphtheriae, C. ulcerans and C. pseudotuberculosis. Moreover, new Corynebacterium species with the potential to produce diphtheria toxin have also been described. Therefore, the detection of the toxin is the most important test in the microbiological diagnosis of diphtheria and other corynebacteria infections. Since the first demonstration in 1888 that DT is a major virulence factor of C. diphtheriae, responsible for the systemic manifestation of the disease, various methods for DT detection have been developed, but the diagnostic usefulness of most of them has not been confirmed on a sufficiently large group of samples. Despite substantial progress in the science and diagnostics of infectious diseases, the Elek test is still the basic recommended diagnostic test for DT detection. The challenge here is the poor availability of an antitoxin and declining experience even in reference laboratories due to the low prevalence of diphtheria in developed countries. However, recent and very promising assays have been developed with the potential for use as rapid point-of-care testing (POCT), such as ICS and LFIA for toxin detection, LAMP for tox gene detection, and biosensors for both.
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Affiliation(s)
| | | | | | | | | | | | - Aleksandra A. Zasada
- Department of Sera and Vaccines Evaluation, National Institute of Public Health NIH—National Research Institute, Chocimska 24, 00-791 Warsaw, Poland; (M.P.); (E.M.); (M.P.); (K.K.-G.); (K.W.); (K.F.)
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2
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O'Boyle S, Barton HE, D'Aeth JC, Cordery R, Fry NK, Litt D, Southgate R, Verrecchia R, Mannes T, Wang TY, Stewart DE, Olufon O, Dickinson M, Ramsay ME, Amirthalingam G. National public health response to an outbreak of toxigenic Corynebacterium diphtheriae among asylum seekers in England, 2022: a descriptive epidemiological study. Lancet Public Health 2023; 8:e766-e775. [PMID: 37777286 DOI: 10.1016/s2468-2667(23)00175-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/10/2023] [Accepted: 07/25/2023] [Indexed: 10/02/2023]
Abstract
BACKGROUND In July, 2022, an increase in diphtheria cases caused by toxigenic Corynebacterium diphtheriae (C diphtheriae) was reported among asylum seekers arriving by small boats to England. Rising case numbers presented challenges for case and contact management in initial reception centres, prompting changes to national guidance and implementation of population-based control measures. This study aimed to describe the outbreak of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022 by use of national surveillance data. METHODS We undertook a descriptive epidemiological analysis of cases of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022, incorporating genomic sequencing data, antibiotic susceptibility testing results, and epidemiological data obtained through the UK Health Security Agency's national enhanced surveillance programme. Health Protection Teams conducted risk assessments, and operational data (including details regarding offer and uptake of antibiotics and vaccinations) were obtained from National Health Service partners supporting the intervention programme. FINDINGS In 2022, C diphtheriae isolates from 86 asylum seekers arriving by small boats were submitted to the National Reference Laboratory for confirmation and testing. Toxigenic C diphtheriae was confirmed for 72 (84%) cases and one individual with typical diphtheritic lesions but from whom no C diphtheriae was isolated from clinical swabs was also included as a probable case, resulting in 73 cases of diphtheria. 71 (97%) were male, 39 (53%) were younger than 18 years, and 36 (49%) presented with cutaneous diphtheria. The prevalence of diphtheria was highest among Afghans (1·3%) compared with all other nationalities (<0·1%). Local antibiotic susceptibility testing identified six cases with a macrolide resistant strain. INTERPRETATION The increase in diphtheria coincided with a high volume of asylum seekers arriving by small boats to England during 2022, and subsequently increased clinical awareness of the disease among this population. Long-term disruption to vaccination programmes in origin countries along with barriers to accessing health care along migrant routes puts asylum seekers arriving by small boats at risk of disease. With arrivals expected to continue in 2023, the UK Health Security Agency has recommended continuation of population-based control measures in England until October, 2023, subject to ongoing review. FUNDING The UK Health Security Agency.
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Affiliation(s)
- Shennae O'Boyle
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
| | - Hannah E Barton
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
| | - Joshua C D'Aeth
- Vaccine Preventable Bacteria Section, Respiratory and Vaccine Preventable Bacteria Reference Unit, Reference Services, UK Health Security Agency, London, UK
| | - Rebecca Cordery
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
| | - Norman K Fry
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK; Vaccine Preventable Bacteria Section, Respiratory and Vaccine Preventable Bacteria Reference Unit, Reference Services, UK Health Security Agency, London, UK
| | - David Litt
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK; Vaccine Preventable Bacteria Section, Respiratory and Vaccine Preventable Bacteria Reference Unit, Reference Services, UK Health Security Agency, London, UK
| | - Rosamund Southgate
- South East Health Protection Team, UK Health Security Agency, London, UK
| | - Robert Verrecchia
- South East Health Protection Team, UK Health Security Agency, London, UK
| | - Trish Mannes
- South East Health Protection Team, UK Health Security Agency, London, UK
| | - Tian Yun Wang
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
| | - Daniel E Stewart
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
| | - Oluwakemi Olufon
- Rapid Investigations Team, Field Services, UK Health Security Agency, London, UK
| | - Michelle Dickinson
- Rapid Investigations Team, Field Services, UK Health Security Agency, London, UK
| | - Mary E Ramsay
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
| | - Gayatri Amirthalingam
- Immunisations and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK
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3
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Kitamura N, Hoan TT, Do HM, Dao TA, Le LT, Le TTT, Doan TTT, Chau TN, Dinh HT, Iwaki M, Senoh M, Efstraciou A, Ho NM, Pham DM, Dang DA, Toizumi M, Fine P, Do HT, Yoshida LM. Seroepidemiology and Carriage of Diphtheria in Epidemic-Prone Area and Implications for Vaccination Policy, Vietnam. Emerg Infect Dis 2023; 29:70-80. [PMID: 36573549 PMCID: PMC9796191 DOI: 10.3201/eid2901.220975] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In 2019, a community-based, cross-sectional carriage survey and a seroprevalence survey of 1,216 persons 1-55 years of age were conducted in rural Vietnam to investigate the mechanism of diphtheria outbreaks. Seroprevalence was further compared with that of an urban area that had no cases reported for the past decade. Carriage prevalence was 1.4%. The highest prevalence, 4.5%, was observed for children 1-5 years of age. Twenty-seven asymptomatic Coerynebacterium diphtheriae carriers were identified; 9 carriers had tox gene-bearing strains, and 3 had nontoxigenic tox gene-bearing strains. Child malnutrition was associated with low levels of diphtheria toxoid IgG, which might have subsequently increased child carriage prevalence. Different immunity patterns in the 2 populations suggested that the low immunity among children caused by low vaccination coverage increased transmission, resulting in symptomatic infections at school-going age, when vaccine-induced immunity waned most. A school-entry booster dose and improved infant vaccination coverage are recommended to control transmissions.
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4
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Polymorphisms of dtxR Gene of Corynebacterium diphtheriae Isolated from Diphtheria Outbreak in Indonesia. Jundishapur J Microbiol 2022. [DOI: 10.5812/jjm-121534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: In Corynebacterium diphtheriae, the dtxR gene plays a role in regulating diphtheria toxin synthesis. The dtxR gene is often used as a marker for identifying C. diphtheriae by the polymerase chain reaction (PCR) method because it is present in all strains of this bacterium. Mutations in the dtxR gene can cause the over-synthesis of diphtheria toxin and reduce PCR assays' sensitivity. Objectives: This study aimed to describe the polymorphisms in the dtxR gene of C. diphtheriae isolated from a diphtheria outbreak in Indonesia. Methods: Forty-eight isolates of C. diphtheriae were obtained from clinical samples (throat/nasopharyngeal swabs) of diphtheria cases and close contacts. The isolates were revived on a Blood Agar Plate (BAP), bacterial colonies were harvested, and deoxyribonucleic acid (DNA) was extracted. The DNA sequencing was carried out using a Whole-genome Sequencing (WGS) approach. The data were converted and analyzed with U-gene software. The dtxR gene analysis was performed with C. diphtheriae PW8 as references. Results: There were 59-point mutation locations in 48 isolates examined. None of these single nucleotide polymorphisms (SNPs) coded for amino acid changes. Based on the mutation pattern, seven clades/groups of the dtxR gene of 48 C. diphtheriae isolates were examined. Conclusions: At least seven types of DNA sequences and more than 50 SNPs of the dtxR gene were identified in 48 C. diphtheriae isolates from a diphtheria outbreak in Indonesia. Although all of them are silent mutations, they must be considered in the design of PCR examination in diphtheria laboratories.
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5
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Development and Application of Dtxr and Tox Genes Targeting Real-Time PCR to Identify Corynebacterium diphtheriae, C. ulcerans, and C. Pseudotuberculosis Simultaneously. Jundishapur J Microbiol 2022. [DOI: 10.5812/jjm-121256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis are known as diphtheria-causing bacteria. Although diphtheria therapy is administered based on the clinical manifestations, some cases are mild and atypical. The immediate and accurate identification of diphtheria-causing bacteria is of paramount importance to prevent the spread of the disease and provide case management as early as possible. Unfortunately, conventional methods as the gold standard are time-consuming. Objectives: This study aimed to develop and implement a multiplex real-time PCR with the dtxR and tox genes as the target to identify three species of diphtheria-causing bacteria and screen their toxigenicity quickly and accurately. Methods: The research sample encompassed seven reference strains, one synthetic DNA, 30 archived isolates, and 924 clinical specimens isolated from 311 diphtheria cases and 613 close contacts. The conventional methods as the gold standard and the established PCR assay were used to verify the results of multiplex real-time PCR developed in this study. Results: The multiplex real-time PCR could identify seven reference strains, one synthetic DNA, and 30 archived isolates as accurately as the conventional methods and the established PCR. Similar to established PCR, the multiplex real-time PCR identified diphtheria-causing bacteria in 120 (38.6%) out of 311 and 12 (2%) out of 613 clinical specimens from diphtheria cases and close contacts, respectively. Meanwhile, the conventional methods identified diphtheria-causing bacteria in 79 (25.4%) out of 311 and three (0.5%) out of 613 clinical specimens. Conclusions: The multiplex real-time PCR developed in this study can be used to identify three species of diphtheria-causing bacteria and screen their toxigenicity quickly and accurately. However, in this study, nodiphtheria-causing bacteria other than C. diphtheriae was found in the clinical samples using the PCR or conventional methods. PCR is more sensitive than the conventional methods and can be used as an additional test in diphtheria laboratories.
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6
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Kawase J, Sakai T, Iwaki M, Umeda K, Fukuma A, Fujisawa N, Kawakami Y, Hayashi H, Wada M. Rapid detection and discrimination of potentially toxigenic Corynebacterium ulcerans and Corynebacterium pseudotuberculosis by multiplex real-time PCR and amplicon melting curve analysis. J Microbiol Methods 2022; 195:106454. [DOI: 10.1016/j.mimet.2022.106454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/16/2022] [Accepted: 03/23/2022] [Indexed: 12/27/2022]
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7
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Devanga Ragupathi NK, Muthuirulandi Sethuvel DP, Murugan D, Ranjan R, Gautam V, Gupta P, Johnson J, Sharma NC, Mutreja A, Haldar P, Kumar A, Bhatnagar P, Sangal L, Veeraraghavan B. Divergent evolution of Corynebacterium diphtheriae in India: An update from National Diphtheria Surveillance network. PLoS One 2021; 16:e0261435. [PMID: 34910778 PMCID: PMC8673651 DOI: 10.1371/journal.pone.0261435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 12/01/2021] [Indexed: 11/22/2022] Open
Abstract
Diphtheria is caused by a toxigenic bacterium Corynebacterium diphtheria which is being an emerging pathogen in India. Since diphtheria morbidity and mortality continues to be high in the country, the present study aimed to study the molecular epidemiology of C. diphtheriae strains from India. A total of 441 diphtheria suspected specimens collected as part of the surveillance programme between 2015 and 2020 were studied. All the isolates were confirmed as C. diphtheriae with standard biochemical tests, ELEK's test, and real-time PCR. Antimicrobial susceptibility testing for the subset of isolates showed intermediate susceptibility to penicillin and complete susceptible to erythromycin and cefotaxime. Isolates were characterized using multi locus sequence typing method. MLST analysis for the 216 C. diphtheriae isolates revealed major diversity among the sequence types. A total of 34 STs were assigned with majority of the isolates belonged to ST466 (30%). The second most common ST identified was ST405 that was present in 14% of the isolates. The international clone ST50 was also seen. The identified STs were grouped into 8 different clonal complexes (CC). The majority belongs to CC5 followed by CC466, CC574 and CC209, however a single non-toxigenic strain belongs to CC42. This epidemiological analysis revealed the emergence of novel STs and the clones with better dissemination properties. This study has also provided information on the circulating strains of C. diphtheriae among the different regions of India. The molecular data generated through surveillance system can be utilized for further actions in concern.
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Affiliation(s)
- Naveen Kumar Devanga Ragupathi
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, United Kingdom
| | | | - Dhivya Murugan
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | - Ranjini Ranjan
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | - Vikas Gautam
- Department of Medical Microbiology, Postgraduate Institute of Medical Education & Research, Chandigarh, India
| | - Prashanth Gupta
- King George’s Medical University, Lucknow, Uttar Pradesh, India
| | | | | | - Ankur Mutreja
- Department of Medicine, Addenbrookes Hospital, University of Cambridge, Cambridge, United Kingdom
- Translational Health Science and Technology Institute (THSTI), Delhi-NCR, India
| | - Pradeep Haldar
- Ministry of Health and Family Welfare, Government of India, New Delhi, India
| | - Arun Kumar
- World Health Organization, New Delhi, India
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8
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Application of Polymerase Chain Reaction in Diphtheria Laboratory Examination: A Field Need. Jundishapur J Microbiol 2021. [DOI: 10.5812/jjm.117884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Indonesia is one of the five countries with the highest number of diphtheria cases worldwide. Diphtheria is caused by the toxigenic strains Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis. The diphtheria-causing bacteria can be identified using conventional and molecular methods, including polymerase chain reaction (PCR) assay. We used the PCR assay as additional testing, because in island countries like Indonesia, specimen transport is a serious challenge to maintaining bacterial survival. Objectives: This study aimed to evaluate the PCR assay as additional testing to identify diphtheria-causing bacteria in the diphtheria laboratory. Methods: In this cross-sectional study, a total of 178 pairs of the throat and nasal swabs from diphtheria suspected cases and close contacts were collected from seven provinces in Indonesia in 2016. All samples were directly identified by the conventional method and multiplex PCR assay. Statistical analysis was conducted using the 2 × 2 tables to determine the sensitivity and specificity of both methods, while the χ2 test was used to examine the correlation between specimen examination delay and the differentiation of results. A P-value < 0.05 was considered as statistically significant. Results: Out of 178 examined samples, eight samples were identified as diphtheria-positive by both the conventional method and PCR assay, while nine samples were only detected by the PCR assay. All diphtheria-causing bacteria found in the positive samples were toxigenic C. diphtheriae. The diphtheria-causing bacteria were found in 27.6% of cases and 6.0% of close contacts using the PCR assay versus 13.8% of cases and 2.7% of close contacts using the conventional method. Statistical analysis showed that the PCR assay is about twice more sensitive than the conventional method. There was a significant correlation between the differentiation of results and > 72 hours’ specimen examination delay with a P-value of 0.04 (< 0.05). Conclusions: The PCR assay is more sensitive than the conventional method to identify diphtheria-causing bacteria and may be applied as additional testing to increase the positivity rate of diphtheria-confirmed cases in Indonesia as an archipelago country where geographical factors and specimen transport are real obstacles.
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Zendri F, Isgren CM, Sinovich M, Richards-Rios P, Hopkins KL, Russell K, Groves N, Litt D, Fry NK, Timofte D. Case Report: Toxigenic Corynebacterium ulcerans Diphtheria-Like Infection in a Horse in the United Kingdom. Front Vet Sci 2021; 8:650238. [PMID: 34141732 PMCID: PMC8203807 DOI: 10.3389/fvets.2021.650238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Corynebacterium ulcerans (C. ulcerans) may cause diphtheria in humans and can be carried by a wide range of animal species including dairy cows and, more recently, dogs and cats that have been increasingly involved in zoonotic trasmission. We isolated and characterized, by WGS, a toxigenic C. ulcerans strain from a diseased horse in the United Kingdom showing clinical signs of respiratory diphtheria comparable to those seen in people. Our results indicate a role for horses as reservoirs for zoonotic C. ulcerans.
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Affiliation(s)
- Flavia Zendri
- Department of Veterinary Anatomy, Physiology and Pathology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
| | - Cajsa Marie Isgren
- Department of Equine Clinical Science, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
| | - Matthew Sinovich
- Department of Equine Clinical Science, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
| | - Peter Richards-Rios
- Department of Veterinary Anatomy, Physiology and Pathology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
| | - Katie L. Hopkins
- Healthcare Associated Infections and Antimicrobial Resistance Division, National Infection Service, Public Health England, London, United Kingdom
| | - Katherine Russell
- Emerging Infections and Zoonoses section, National Infection Service, Public Health England, London, United Kingdom
| | - Natalie Groves
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, United Kingdom
| | - David Litt
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, United Kingdom
| | - Norman K. Fry
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, United Kingdom
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - Dorina Timofte
- Department of Veterinary Anatomy, Physiology and Pathology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
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10
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Strauss RA, Herrera-Leon L, Guillén AC, Castro JS, Lorenz E, Carvajal A, Hernandez E, Navas T, Vielma S, Lopez N, Lopez MG, Aurenty L, Navas V, Rosas MA, Drummond T, Martínez JG, Hernández E, Bertuglia F, Andrade O, Torres J, May J, Herrera-Leon S, Eibach D. Molecular and epidemiologic characterization of the diphtheria outbreak in Venezuela. Sci Rep 2021; 11:6378. [PMID: 33737710 PMCID: PMC7973433 DOI: 10.1038/s41598-021-85957-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/09/2021] [Indexed: 11/09/2022] Open
Abstract
In 2016, Venezuela faced a large diphtheria outbreak that extended until 2019. Nasopharyngeal or oropharyngeal samples were prospectively collected from 51 suspected cases and retrospective data from 348 clinical records was retrieved from 14 hospitals between November 2017 and November 2018. Confirmed pathogenic Corynebactrium isolates were biotyped. Multilocus Sequence Typing (MLST) was performed followed by next-generation-based core genome-MLST and minimum spanning trees were generated. Subjects between 10 and 19 years of age were mostly affected (n = 95; 27.3%). Case fatality rates (CFR) were higher in males (19.4%), as compared to females (15.8%). The highest CFR (31.1%) was observed among those under 5, followed by the 40 to 49 age-group (25.0%). Nine samples corresponded to C. diphtheriae and 1 to C. ulcerans. Two Sequencing Types (ST), ST174 and ST697 (the latter not previously described) were identified among the eight C. diphtheriae isolates from Carabobo state. Cg-MLST revealed only one cluster also from Carabobo. The Whole Genome Sequencing analysis revealed that the outbreak seemed to be caused by different strains with C. diphtheriae and C. ulcerans coexisting. The reemergence and length of this outbreak suggest vaccination coverage problems and an inadequate control strategy.
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Affiliation(s)
| | | | | | - Julio S Castro
- Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | - Eva Lorenz
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ana Carvajal
- Hospital Universitario de Caracas, Caracas, Venezuela
| | | | - Trina Navas
- Hospital General Los Magallanes de Catia, Caracas, Venezuela
| | | | | | - Maria G Lopez
- Hospital de Niños José Manuel de Los Ríos, Caracas, Venezuela
| | - Lisbeth Aurenty
- Hospital de Niños José Manuel de Los Ríos, Caracas, Venezuela
| | - Valeria Navas
- Hospital Universitario de Maracaibo, Maracaibo, Venezuela
| | - Maria A Rosas
- Ciudad Hospitalaria Dr Henrique Tejera, Carabobo, Venezuela
| | | | | | | | | | - Omaira Andrade
- Centro Clinico-Materno Leopoldo Aguerrevere, Caracas, Venezuela
| | - Jaime Torres
- Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | - Jürgen May
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Daniel Eibach
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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11
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Sunarno, Khariri, Muna F, Sariadji K, Rukminiati Y, Febriyana D, Febrianti T, Saraswati RD, Susanti I, Puspandari N, Karuniawati A, Malik A, Soebandrio A. New approach for the identification of potentially toxigenic Corynebacterium sp. using a multiplex PCR assay. J Microbiol Methods 2021; 184:106198. [PMID: 33713727 DOI: 10.1016/j.mimet.2021.106198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 10/22/2022]
Abstract
In diphtheria laboratory examinations, the PCR test can be applied to isolates and clinical specimens. This study aimed to develop a PCR assay to identify the species and toxigenicity of diphtheria-causing bacteria, including the prediction of some NTTB types. Seven reference isolates, four synthetic DNA samples, 36 stored isolates, and 487 clinical samples used for PCR optimization. The PCR results was confirmed by DNA sequence analysis. The results of the PCR examination of the 7 reference isolates and 36 stored isolates were similar to the results obtained using conventional methods as gold standard, both for diphtheria-causing and non-diphtheria-causing bacteria. The validation of the PCR results using DNA sequence analysis showed that there was no mispriming or misamplification. The multiplex PCR assay developed in this study could correctly identify the species and toxigenicity of diphtheria-causing bacteria, including the prediction of some NTTB types not yet covered by established PCR methods.
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Affiliation(s)
- Sunarno
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia.
| | - Khariri
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Fauzul Muna
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Kambang Sariadji
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Yuni Rukminiati
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Dwi Febriyana
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Tati Febrianti
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Ratih Dian Saraswati
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Ida Susanti
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Nelly Puspandari
- Centre for Research and Development of Biomedical and Basic Health Technology, National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | | | - Amarila Malik
- Division of Microbiology and Biotechnology Pharmacy, Faculty of Pharmacy, Universitas Indonesia, Depok, Indonesia
| | - Amin Soebandrio
- Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia; Eijkman Institute for Molecular Biology, Jakarta, Indonesia
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12
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Rosana Y, Prilandari LI, Ajisman R, Hartono TS, Yasmon A. Detection of toxin-producing Corynebacterium diphtheriae from throat swabs of diphtheria patients using duplex real-time PCR. IRANIAN JOURNAL OF MICROBIOLOGY 2020; 12:508-515. [PMID: 33613904 PMCID: PMC7884264 DOI: 10.18502/ijm.v12i6.5024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background and Objectives Diphtheria is a potentially fatal disease caused by toxigenic bacterial infection, particularly from Corynebacterium diphtheriae (C. diphtheriae). Isolation of C. diphtheriae is technically lacking in sensitivity, and Elek's test to detect toxin production has several difficulties associated with its application. Duplex real-time PCR to throat swab of suspected diphtheria patients can detect both bacteria and toxin-encoding genes simultaneously, faster, with higher sensitivity and specificity. Materials and Methods A total of 89 consecutive throat swabs from suspected diphtheria patients were collected from Sulianti Saroso Infectious Disease Hospital, Jakarta, during 2018 to 2019. Two pairs of primers and probes, targeting the rpoB gene of C. diphtheriae and the A-subunit of the diphtheria toxin gene, were used in this study. Parameters including annealing temperature, concentration of primers and probes, inhibitors, cross-reaction and detection limit were all optimized. Elek's toxigenicity test and clinical data were analyzed for comparison. Results The optimum annealing temperature was 55°C. The concentrations of Cd primer, Tox primer, Cd probe and Tox probe were 0.4, 0.6, 0.5 and 0.625 µM, respectively. DNA elution and template volumes were 50 µL and 5 µL. The detection limit was 2 CFU/mL. No cross-reaction with other microorganisms was observed. Of the 89 samples, duplex real-time PCR gave better results than the standard test, with 19 (21.3%) and 10 (11.2%) patients diagnosed with diphtheria, respectively. Conclusion Duplex real-time PCR increases the rate of laboratory diagnosis of diphtheria, compared to the standard method to detect potentially toxigenic C. diphtheriae.
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Affiliation(s)
- Yeva Rosana
- Department of Microbiology, School of Medicine, Universitas Indonesia, Ciptomangunkusumo Hospital, Jakarta, Indonesia
| | - Luh Inta Prilandari
- Department of Microbiology, Clinical Microbiologist Program, School of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Ruhsyahadati Ajisman
- Department of Microbiology, Clinical Microbiologist Program, School of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Teguh Sarry Hartono
- Department of Microbiology, Sulianti Saroso Infectious Diseases Hospital, Jakarta, Indonesia
| | - Andi Yasmon
- Department of Microbiology, School of Medicine, Universitas Indonesia, Ciptomangunkusumo Hospital, Jakarta, Indonesia
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13
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Gower CM, Scobie A, Fry NK, Litt DJ, Cameron JC, Chand MA, Brown CS, Collins S, White JM, Ramsay ME, Amirthalingam G. The changing epidemiology of diphtheria in the United Kingdom, 2009 to 2017. ACTA ACUST UNITED AC 2020; 25. [PMID: 32209165 PMCID: PMC7096772 DOI: 10.2807/1560-7917.es.2020.25.11.1900462] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background Diphtheria is a potentially fatal disease caused by toxigenic strains of Corynebacterium diphtheriae, C. ulcerans or C. pseudotuberculosis. Aim Our objective was to review the epidemiology of diphtheria in the United Kingdom (UK) and the impact of recent changes in public health management and surveillance. Methods Putative human toxigenic diphtheria isolates in the UK are sent for species confirmation and toxigenicity testing to the National Reference Laboratory. Clinical, epidemiological and microbiological information for toxigenic cases between 2009 and 2017 are described in this population-based prospective surveillance study. Results There were 33 toxigenic cases of diphtheria aged 4 to 82 years. Causative species were C. diphtheriae (n = 18) and C. ulcerans (n = 15). Most C. diphtheriae cases were cutaneous (14/18) while more than half of C. ulcerans cases had respiratory presentations (8/15). Two thirds (23/33) of cases were inadequately immunised. Two cases with C. ulcerans infections died, both inadequately immunised. The major risk factor for C. diphtheriae aquisition was travel to an endemic area and for C. ulcerans, contact with a companion animal. Most confirmed C. diphtheriae or C. ulcerans isolates (441/507; 87%) submitted for toxigenicity testing were non-toxigenic, however, toxin positivity rates were higher (15/23) for C. ulcerans than C. diphtheriae (18/469). Ten non-toxigenic toxin gene-bearing (NTTB) C. diphtheriae were also detected. Conclusion Diphtheria is a rare disease in the UK. In the last decade, milder cutaneous C. diphtheriae cases have become more frequent. Incomplete vaccination status was strongly associated with the risk of hospitalisation and death.
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Affiliation(s)
- Charlotte M Gower
- These authors contributed equally to this work.,Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - Antonia Scobie
- Vaccine Preventable Bacteria Section, National Infection Service Laboratories, Public Health England, London, United Kingdom.,These authors contributed equally to this work
| | - Norman K Fry
- Vaccine Preventable Bacteria Section, National Infection Service Laboratories, Public Health England, London, United Kingdom.,Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - David J Litt
- Vaccine Preventable Bacteria Section, National Infection Service Laboratories, Public Health England, London, United Kingdom
| | - J Claire Cameron
- NHS National Services Scotland, Health Protection Scotland, Meridan Court, Glasgow, United Kingdom
| | | | - Colin S Brown
- Department of Infection, Royal Free London NHS Foundation Trust, London, United Kingdom.,Vaccine Preventable Bacteria Section, National Infection Service Laboratories, Public Health England, London, United Kingdom
| | - Sarah Collins
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - Joanne M White
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - Mary E Ramsay
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
| | - Gayatri Amirthalingam
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, United Kingdom
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14
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Abstract
The introduction of treatment and systematic vaccination has significantly reduced diphtheria mortality; however, toxigenic strains continue to circulate worldwide. The emergence of an indigenous diphtheria case with fatal outcome in Greece, after 30 years, raised challenges for laboratory confirmation, clinical and public health management. Toxigenic Corynebacterium diphtheriae was isolated from an incompletely vaccinated 8-year-old boy with underlying conditions. The child passed away due to respiratory distress syndrome, before the administration of diphtheria antitoxin (DAT). All close contacts in family, school and hospital settings were investigated. Pharyngeal swabs were obtained to determine asymptomatic carriage. Chemoprophylaxis was given for 7 days to all close contacts and a booster dose to those incompletely vaccinated. Testing revealed a classmate, belonging to a subpopulation group (Roma), and incompletely vaccinated, as an asymptomatic carrier with an indistinguishable toxigenic strain (same novel multilocus sequence type, designated ST698). This case highlights the role of asymptomatic carriage, as the entry of toxigenic strains into susceptible populations can put individuals and their environment at risk. Maintenance of high-level epidemiological and microbiological surveillance, implementation of systematic vaccination in children and adults with primary and booster doses, availability of a DAT stockpile, and allowing timely administration are the cornerstone to prevent similar incidents in the future.
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15
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Detection and Characterization of Diphtheria Toxin Gene-Bearing Corynebacterium Species through a New Real-Time PCR Assay. J Clin Microbiol 2020; 58:JCM.00639-20. [PMID: 32727830 DOI: 10.1128/jcm.00639-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/26/2020] [Indexed: 11/20/2022] Open
Abstract
Respiratory diphtheria, characterized by a firmly adherent pseudomembrane, is caused by toxin-producing strains of Corynebacterium diphtheriae, with similar illness produced occasionally by toxigenic Corynebacterium ulcerans or, rarely, Corynebacterium pseudotuberculosis While diphtheria laboratory confirmation requires culture methods to determine toxigenicity, real-time PCR (RT-PCR) provides a faster method to detect the toxin gene (tox). Nontoxigenic tox-bearing (NTTB) Corynebacterium isolates have been described, but impact of these isolates on the accuracy of molecular diagnostics is not well characterized. Here, we describe a new triplex RT-PCR assay to detect tox and distinguish C. diphtheriae from the closely related species C. ulcerans and C. pseudotuberculosis Analytical sensitivity and specificity of the assay were assessed in comparison to culture using 690 previously characterized microbial isolates. The new triplex assay characterized Corynebacterium isolates accurately, with 100% analytical sensitivity for all targets. Analytical specificity with isolates was 94.1%, 100%, and 99.5% for tox, Diph_rpoB, and CUP_rpoB targets, respectively. Twenty-nine NTTB Corynebacterium isolates, representing 5.9% of 494 nontoxigenic isolates tested, were detected by RT-PCR. Whole-genome sequencing of NTTB isolates revealed varied mutations putatively underlying their lack of toxin production, as well as eight isolates with no mutation in tox or the promoter region. This new Corynebacterium RT-PCR method provides a rapid tool to screen isolates and identify probable diphtheria cases directly from specimens. However, the sporadic occurrence of NTTB isolates reinforces the viewpoint that diphtheria culture diagnostics continue to provide the most accurate case confirmation.
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16
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Abbott Y, Efstratiou A, Brennan G, Hallanan S, Leggett B, Leonard FC, Markey BK, Tuite C, Fry NK. Toxigenic Corynebacterium ulcerans associated with upper respiratory infections in cats and dogs. J Small Anim Pract 2020; 61:554-560. [PMID: 32734615 DOI: 10.1111/jsap.13185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 01/02/2023]
Abstract
OBJECTIVES To describe infection in companion animals with the zoonotic pathogen Corynebacterium ulcerans and to determine its prevalence in clinically-affected and healthy animals. MATERIALS AND METHODS The clinical presentation and treatment of three cases of C. ulcerans infection is described. Two studies to determine C. ulcerans prevalence rates were undertaken: (a) a prospective study of nasal samples from healthy animals, 479 dogs and 72 cats; (b) a retrospective analysis of records of nasal samples collected over a 10-year period from 189 dogs and 64 cats affected by respiratory signs. RESULTS Toxigenic C. ulcerans was isolated from four cats with nasal discharge while concurrent C. ulcerans and mecC methicillin-resistant S. aureus infection was detected in a dog suffering from chronic nasal discharge. Clinical features were not distinctive and all cases recovered following antimicrobial treatment. Multilocus sequence typing supported a common source for isolates from the shelter cats. Carriage rates of C. ulcerans in healthy animals were 0.42% (2/479) in dogs and 0.00% (0/72) in cats whereas in animals with signs of upper respiratory tract infection prevalence rates were 0.53% (1/189) in dogs and 6.25% (4/64) in cats. CLINICAL SIGNIFICANCE Clinicians should be aware that dogs and cats can be infected with (or carriers of) toxigenic C. ulcerans Considering the potential zoonotic risk, assistance from medical and public health colleagues should be sought in confirmed cases.
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Affiliation(s)
- Y Abbott
- Veterinary Pathobiology Section, School of Veterinary Medicine, University College Dublin, Belfield, Stillorgan Road, Dublin, D04 W6F6, Ireland
| | - A Efstratiou
- WHO Global Reference Centre for Diphtheria and Streptococcal Infections, Public Health England, National Infection Service, 61 Colindale Avenue, London, NW9 5EQ, UK
| | - G Brennan
- National MRSA Reference Laboratory, St. James's Hospital, James's Street, Dublin 8, Ireland
| | - S Hallanan
- Riverforest Veterinary Centre, Riverforest Court, Captain's Hill, Leixlip, Co. Kildare, W23 A5N4, Ireland
| | - B Leggett
- Veterinary Pathobiology Section, School of Veterinary Medicine, University College Dublin, Belfield, Stillorgan Road, Dublin, D04 W6F6, Ireland
| | - F C Leonard
- Veterinary Pathobiology Section, School of Veterinary Medicine, University College Dublin, Belfield, Stillorgan Road, Dublin, D04 W6F6, Ireland
| | - B K Markey
- Veterinary Pathobiology Section, School of Veterinary Medicine, University College Dublin, Belfield, Stillorgan Road, Dublin, D04 W6F6, Ireland
| | - C Tuite
- Fairview Veterinary Hospital, 13 Fairview Strand, Dublin, D03 P27, Ireland
| | - N K Fry
- Vaccine Preventable Bacteria Section, Public Health England, National Infection Service, 61 Colindale Avenue, London, NW9 5EQ, UK.,Immunisation and Countermeasures Division, Public Health England, National Infection Service, 61 Colindale Avenue, London, NW9 5EQ, UK
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17
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Abstract
We report two cases of respiratory toxigenic Corynebacterium diphtheriae infection in fully vaccinated UK born adults following travel to Tunisia in October 2019. Both patients were successfully treated with antibiotics and neither received diphtheria antitoxin. Contact tracing was performed following a risk assessment but no additional cases were identified. This report highlights the importance of maintaining a high index of suspicion for re-emerging infections in patients with a history of travel to high-risk areas outside Europe.
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18
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Corynebacterium rouxii sp. nov., a novel member of the diphtheriae species complex. Res Microbiol 2020; 171:122-127. [PMID: 32119905 DOI: 10.1016/j.resmic.2020.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 12/18/2022]
Abstract
A group of six clinical isolates previously identified as Corynebacterium diphtheriae biovar Belfanti, isolated from human cutaneous or peritoneum infections and from one dog, were characterized by genomic sequencing, biochemical analysis and MALDI-TOF mass spectrometry. The six isolates were negative for the diphtheria toxin gene. Phylogenetic analyses showed that the six isolates (including FRC0190T) are clearly demarcated from C. diphtheriae, Corynebacterium belfantii, Corynebacterium ulcerans and Corynebacterium pseudotuberculosis. The average nucleotide identity of FRC0190T with C. diphtheriae NCTC11397T was 92.6%, and was 91.8% with C. belfantii FRC0043T. C. diphtheriae subsp. lausannense strain CHUV2995T appeared to be a later heterotypic synonym of C. belfantii (ANI, 99.3%). Phenotyping data revealed an atypical negative or heterogeneous intermediate maltose fermentation reaction for the six isolates. MALDI-TOF mass spectrometry differentiated the new group from the other Corynebacterium taxa by the presence of specific spectral peaks. rpoB sequences showed identity to atypical, maltose-negative C. diphtheriae biovar Belfanti isolates previously described from two cats in the USA. We propose the name Corynebacterium rouxii sp. nov. for the novel group, with FRC0190T (= CIP 111752T = DSM 110354T) as type strain.
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19
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Sharma NC, Efstratiou A, Mokrousov I, Mutreja A, Das B, Ramamurthy T. Diphtheria. Nat Rev Dis Primers 2019; 5:81. [PMID: 31804499 DOI: 10.1038/s41572-019-0131-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 01/09/2023]
Abstract
Diphtheria is a potentially fatal infection mostly caused by toxigenic Corynebacterium diphtheriae strains and occasionally by toxigenic C. ulcerans and C. pseudotuberculosis strains. Diphtheria is generally an acute respiratory infection, characterized by the formation of a pseudomembrane in the throat, but cutaneous infections are possible. Systemic effects, such as myocarditis and neuropathy, which are associated with increased fatality risk, are due to diphtheria toxin, an exotoxin produced by the pathogen that inhibits protein synthesis and causes cell death. Clinical diagnosis is confirmed by the isolation and identification of the causative Corynebacterium spp., usually by bacterial culture followed by enzymatic and toxin detection tests. Diphtheria can be treated with the timely administration of diphtheria antitoxin and antimicrobial therapy. Although effective vaccines are available, this disease has the potential to re-emerge in countries where the recommended vaccination programmes are not sustained, and increasing proportions of adults are becoming susceptible to diphtheria. Thousands of diphtheria cases are still reported annually from several countries in Asia and Africa, along with many outbreaks. Changes in the epidemiology of diphtheria have been reported worldwide. The prevalence of toxigenic Corynebacterium spp. highlights the need for proper clinical and epidemiological investigations to quickly identify and treat affected individuals, along with public health measures to prevent and contain the spread of this disease.
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Affiliation(s)
- Naresh Chand Sharma
- Laboratory Department, Maharishi Valmiki Infectious Diseases Hospital, Delhi, India
| | - Androulla Efstratiou
- WHO Collaborating Centre for Diphtheria and Streptococcal Infections, Reference Microbiology Division, Public Health England, London, UK
| | - Igor Mokrousov
- Laboratory of Molecular Epidemiology and Evolutionary Genetics, St. Petersburg Pasteur Institute, St. Petersburg, Russia
| | - Ankur Mutreja
- Global Health-Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Bhabatosh Das
- Infection and Immunology Division, Translational Health Science and Technology Institute, Faridabad, India
| | - Thandavarayan Ramamurthy
- Infection and Immunology Division, Translational Health Science and Technology Institute, Faridabad, India.
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20
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Abstract
Background Increasingly, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) has been used to provide rapid, inexpensive and precise identification of bacteria, including Corynebacterium species. Only three Corynebacterium species are able to produce diphtheria toxin (DT), and strains recovered may be either toxin-producing or non-toxin-producing. It appears the more precise bacterial identification provided by MALDI-TOF systems has led to an increase in requests submitted to the National Microbiology Laboratory (NML) for toxin testing. Objective To describe the number of isolates identified as C. diphtheriae, C. ulcerans and C. pseudotuberculosis, submitted to the NML between January 2006 and July 30, 2019, including their geographic area, source, and whether they produce DT. Methods Referrals to the NML of human or animal isolates that were identified as any of those three Corynebacterium species were studied with respect to province, source and toxigenicity. Species identification was confirmed and then specimens were tested by polymerase chain reaction for the presence of tox genes and, if positive, for expression of DT by the modified Elek method. Analysis was descriptive. Results Over the study period, 639 isolates were identified as C. diphtheriae, 22 isolates as C. ulcerans; no isolates were identified as C. pseudotuberculosis. There was an increase in C. diphtheriae referrals for DT testing: from eight per year in 2006 to an average of 15 per month in 2019, or a 1,200% increase over the 13.6-year period. The referrals were primarily from western Canada (n=609/639; 95%). Most (638/639, 99%) were human isolates and most were obtained from cutaneous sites. Of those isolates, 87/639 (13.6%) were found to be toxigenic and 552/639 (86.4%) non-toxigenic. Among C. ulcerans referrals, 17/22 (77%) were from humans and five (23%) were from animals, with 10/22 (45%) being toxigenic. Conclusion There has been a marked increase in referrals to the NML for DT testing of Corynebacterium species. This could be due to the enhanced ability to identify these bacteria using MALDI-TOF systems. Ongoing monitoring will help to assess whether the increase is due solely to increased precision of diagnosis or whether these are emerging cutaneous pathogens.
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21
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Martini H, Soetens O, Litt D, Fry NK, Detemmerman L, Wybo I, Desombere I, Efstratiou A, Piérard D. Diphtheria in Belgium: 2010-2017. J Med Microbiol 2019; 68:1517-1525. [PMID: 31418673 DOI: 10.1099/jmm.0.001039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In Western Europe, the incidence of both respiratory and cutaneous diphtheria, caused by toxin-producing Corynebacterium diphtheriae, Corynebacterium ulcerans or Corynebacterium pseudotuberculosis, has been low over the past few decades thanks to the use of an effective vaccine and a high level of vaccination coverage. However, the disease has still not been eradicated and continues to occur in all of Europe. In order to prevent sequelae or a fatal outcome, diphtheria antitoxin (DAT) should be administered to suspected diphtheria patients as soon as possible, but economic factors and issues concerning regulations have led to poor availability of DAT in many countries. The European Centre for Disease Prevention and Control and World Health Organization have called for European Union-wide solutions to this DAT-shortage. In order to illustrate the importance of these efforts and underline the need for continued diphtheria surveillance, we present data on all registered cases of toxigenic and non-toxigenic C. diphtheriae, C. ulcerans and C. pseudotuberculosis in Belgium during the past decade, up to and including 2017.
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Affiliation(s)
- Helena Martini
- Department of Microbiology, National Reference Centre for toxigenic corynebacteria, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Oriane Soetens
- Department of Microbiology, National Reference Centre for toxigenic corynebacteria, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - David Litt
- Respiratory and Vaccine Preventable Bacteria Reference Unit, Public Health England - National Infection Service, London, UK
| | - Norman K Fry
- Immunisation and Countermeasures Division, Public Health England - National Infection Service, London, UK.,Respiratory and Vaccine Preventable Bacteria Reference Unit, Public Health England - National Infection Service, London, UK
| | - Liselot Detemmerman
- Present address: LaCAR MDx Technologies, Liège, Belgium.,Department of Microbiology, National Reference Centre for toxigenic corynebacteria, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Ingrid Wybo
- Department of Microbiology, National Reference Centre for toxigenic corynebacteria, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Isabelle Desombere
- Present address: LaCAR MDx Technologies, Liège, Belgium.,SD Infectious Diseases in Humans, Service Immune Response, National Reference Centre for toxigenic corynebacteria, Sciensano (Public Health Belgium), Brussels, Belgium
| | - Androulla Efstratiou
- WHO Global Collaborating Centre for Reference and Research on Diphtheria and Streptococcal Infections, Public Health England - National Infection Service, London, UK
| | - Denis Piérard
- Department of Microbiology, National Reference Centre for toxigenic corynebacteria, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
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22
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Edwards D, Kent D, Lester C, Brown CS, Murphy ME, Brown NM, Sule O, Itani A, Chand M, Trindall A, Pearson C, Roddick I, Fry NK, Hoffmann J, Iyanger N, Kemp L, White J, Javid B, Ramsay ID, Zenner D, Ahmed A, Amirthalingam G, Salimee S, Litt D, Reacher M. Transmission of toxigenic Corynebacterium diphtheriae by a fully immunised resident returning from a visit to West Africa, United Kingdom, 2017. ACTA ACUST UNITED AC 2019; 23. [PMID: 30280689 PMCID: PMC6169202 DOI: 10.2807/1560-7917.es.2018.23.39.1700681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In early 2017, a United Kingdom (UK)-born person in their 20s presented with a skin ulcer on the foot 3 weeks after returning from Ghana. The patient had last received a diphtheria-containing vaccine in 2013, completing the recommended course. MALDI-TOF of a cutaneous swab identified Corynebacterium diphtheriae. Real-time PCR ascertained the species and presence of the diphtheria toxin gene. An Elek test confirmed toxigenicity. The isolate was macrolide sensitive and penicillin resistant. The local Public Health England (PHE) Health Protection Team obtained the patient's clinical history and traced contacts to inform appropriate public health action. One close contact (in their early 80s with uncertain immunisation status who had not recently travelled) had a positive throat swab for toxigenic C. diphtheriae and reported a history of mild coryzal symptoms. Multilocus sequence typing revealed that strains from the index case and contact had Sequence Type 463. Diphtheria is extremely rare in the UK due to high vaccine coverage and this is the first documented transmission in 30 years. Clinicians and laboratory staff should remain highly suspicious of lesions in overseas travellers, even when patients are fully vaccinated. Older individuals who might not have completed a full immunisation course may have higher diphtheria susceptibility.
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Affiliation(s)
- David Edwards
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | - Dianne Kent
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | - Caroline Lester
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | | | - Michael E Murphy
- Department of Microbiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Nicholas M Brown
- PHE Public Health Laboratory Cambridge, Public Health England, Cambridge, United Kingdom
| | - Olajumoke Sule
- PHE Public Health Laboratory Cambridge, Public Health England, Cambridge, United Kingdom
| | | | - Meera Chand
- NIHR Health Protection Research Unit in Respiratory Infections, Public Health England, London, United Kingdom
| | - Amy Trindall
- Field Epidemiology Service, Public Health England, Cambridge, United Kingdom
| | - Callum Pearson
- Field Epidemiology Service, Public Health England, Cambridge, United Kingdom
| | - Iain Roddick
- Field Epidemiology Service, Public Health England, Cambridge, United Kingdom
| | - Norman K Fry
- National Infection Service, Public Health England, London, United Kingdom
| | - Jorg Hoffmann
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | - Nalini Iyanger
- National Infection Service, Public Health England, London, United Kingdom
| | | | - Joanne White
- National Infection Service, Public Health England, London, United Kingdom
| | - Babak Javid
- Department of Medicine, University of Cambridge School of Clinical Medicine, University of Cambridge Hospitals Trust, Cambridge, United Kingdom
| | - Isobel D Ramsay
- Department of Medicine, University of Cambridge School of Clinical Medicine, University of Cambridge Hospitals Trust, Cambridge, United Kingdom
| | - Dominik Zenner
- National Infection Service, Public Health England, London, United Kingdom
| | - Aliko Ahmed
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | - Gayatri Amirthalingam
- Immunisation, Hepatitis and Blood Safety Department, National Infection Service, Public Health England, London, United Kingdom
| | - Sultan Salimee
- East of England Health Protection Team, Public Health England, Thetford, United Kingdom
| | - David Litt
- National Infection Service, Public Health England, London, United Kingdom
| | - Mark Reacher
- Field Epidemiology Service, Public Health England, Cambridge, United Kingdom
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23
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Badell E, Guillot S, Tulliez M, Pascal M, Panunzi LG, Rose S, Litt D, Fry NK, Brisse S. Improved quadruplex real-time PCR assay for the diagnosis of diphtheria. J Med Microbiol 2019; 68:1455-1465. [DOI: 10.1099/jmm.0.001070] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Edgar Badell
- Institut Pasteur, National Reference Center for Corynebacteria of the diphtheriae complex, Paris, France
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - Sophie Guillot
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - Marie Tulliez
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - Marine Pascal
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | | | - Samuel Rose
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, UK
| | - David Litt
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, UK
| | - Norman K. Fry
- Immunisation and Countermeasures Division, National Infection Service, Public Health England, London, UK
- Respiratory and Vaccine Preventable Bacteria Reference Unit, National Infection Service, Public Health England, London, UK
| | - Sylvain Brisse
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
- Institut Pasteur, National Reference Center for Corynebacteria of the diphtheriae complex, Paris, France
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Muthuirulandi Sethuvel DP, Subramanian N, Pragasam AK, Inbanathan FY, Gupta P, Johnson J, Sharma NC, Hemvani N, Veeraraghavan B, Anandan S, Sangal L. Insights to the diphtheria toxin encoding prophages amongst clinical isolates of Corynebacterium diphtheriae from India. Indian J Med Microbiol 2019; 37:423-425. [PMID: 32003344 DOI: 10.4103/ijmm.ijmm_19_469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Diphtheria is a dreadful disease caused by Corynebacterium diphtheriae. Lysogenised bacteriophages carrying toxin gene in C. diphtheriae can make the strain toxigenic. However, such phage disseminates the toxin genes to other strains when it undergoes lytic phase. As little is known about the phage diversity in C. diphtheriae in India, the present study was undertaken to investigate the prophages integrated into the genome of 29 clinical isolates of C. diphtheriae using whole-genome shotgun sequencing. Amongst these isolates, 27 were toxigenic, while 2 were non-toxigenic strains. Of the 27 toxigenic strains, all harbored known phages carrying toxin gene and two other phages with unknown function. However, the two non-toxin strains did not harbour any of the phages in the genome. It is imperative to devise prevention strategies that hinder the dissemination of toxin by prophages, as it may increase the complications of diphtheria post-immunisation.
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Affiliation(s)
| | | | | | | | - Prashant Gupta
- King George's Medical University, Lucknow, Uttar Pradesh, India
| | | | | | - Nanda Hemvani
- Choithram Hospital and Research Centre, Indore, Madhya Pradesh, India
| | | | - Shalini Anandan
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | - Lucky Sangal
- World Health Organization Country Office, New Delhi, India
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Othieno R, Mark K, Etherson M, Foster G, Murray S, Kalima P, Fry NK, Cameron C, Strachan J. A case of cutaneous toxigenic Corynebacterium ulcerans likely acquired from a domestic dog. Access Microbiol 2019; 1:e000025. [PMID: 32974539 PMCID: PMC7481734 DOI: 10.1099/acmi.0.000025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/06/2019] [Indexed: 11/29/2022] Open
Abstract
Introduction Corynebacterium ulcerans can produce diphtheria toxin and although still rare, is now the predominant cause of toxigenic diphtheria infection in the UK, making this organism of great clinical and public health importance. Here we describe a cutaneous case, likely secondary to domestic animal contact. Case presentation A 60-year-old female presented with a slow-healing finger-burn wound. A skin swab cultured Corynebacterium ulcerans, which was confirmed to be toxin producing. She resided with her partner and two dogs, one of which had a chronic skin lesion. Her most recent diphtheria vaccine was in 2009. Four close contacts were identified, two of whom were healthcare professionals, and nose and throat swabs were obtained. The patient was treated with clarithromycin (14 day course), diphtheria vaccine and excluded from work until completion of antibiotics and negative clearance swabs. Contacts were given erythromycin (7 day course), vaccinated and healthcare worker contacts excluded from work until swab negative. A veterinary practitioner swabbed the throats and a skin lesion of their dogs. One contact (partner of patient) and all dog swabs were positive. Partial allelic profiles from MLST supported an epidemiological link. The dogs were treated with antibiotics and antimicrobial skin wash. Repeat swabs for the index case, contact and both dogs were negative following treatment. Conclusion This was a rare case of cutaneous diphtheria secondary to Corynebacterium ulcerans with domestic animals the most likely source, although human-to-human contact could not be excluded, with important human and animal public health implications.
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Affiliation(s)
| | - Kate Mark
- National Health Services (NHS) Lothian, Edinburgh, UK
| | | | | | | | - Pota Kalima
- National Health Services (NHS) Lothian, Edinburgh, UK
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Tagini F, Pillonel T, Croxatto A, Bertelli C, Koutsokera A, Lovis A, Greub G. Distinct Genomic Features Characterize Two Clades of Corynebacterium diphtheriae: Proposal of Corynebacterium diphtheriae Subsp. diphtheriae Subsp. nov. and Corynebacterium diphtheriae Subsp. lausannense Subsp. nov. Front Microbiol 2018; 9:1743. [PMID: 30174653 PMCID: PMC6108181 DOI: 10.3389/fmicb.2018.01743] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/12/2018] [Indexed: 12/25/2022] Open
Abstract
Corynebacterium diphtheriae is the etiological agent of diphtheria, a disease caused by the presence of the diphtheria toxin. However, an increasing number of records report non-toxigenic C. diphtheriae infections. Here, a C. diphtheriae strain was recovered from a patient with a past history of bronchiectasis who developed a severe tracheo-bronchitis with multiple whitish lesions of the distal trachea and the mainstem bronchi. Whole-genome sequencing (WGS), performed in parallel with PCR targeting the toxin gene and the Elek test, provided clinically relevant results in a short turnaround time, showing that the isolate was non-toxigenic. A comparative genomic analysis of the new strain (CHUV2995) with 56 other publicly available genomes of C. diphtheriae revealed that the strains CHUV2995, CCUG 5865 and CMCNS703 share a lower average nucleotide identity (ANI) (95.24 to 95.39%) with the C. diphtheriae NCTC 11397T reference genome than all other C. diphtheriae genomes (>98.15%). Core genome phylogeny confirmed the presence of two monophyletic clades. Based on these findings, we propose here two new C. diphtheriae subspecies to replace the lineage denomination used in previous multilocus sequence typing studies: C. diphtheriae subsp. lausannense subsp. nov. (instead of lineage-2), regrouping strains CHUV2995, CCUG 5865, and CMCNS703, and C. diphtheriae subsp. diphtheriae subsp. nov, regrouping all other C. diphtheriae in the dataset (instead of lineage-1). Interestingly, members of subspecies lausannense displayed a larger genome size than subspecies diphtheriae and were enriched in COG categories related to transport and metabolism of lipids (I) and inorganic ion (P). Conversely, they lacked all genes involved in the synthesis of pili (SpaA-type, SpaD-type and SpaH-type), molybdenum cofactor and of the nitrate reductase. Finally, the CHUV2995 genome is particularly enriched in mobility genes and harbors several prophages. The genome encodes a type II-C CRISPR-Cas locus with 2 spacers that lacks csn2 or cas4, which could hamper the acquisition of new spacers and render strain CHUV2995 more susceptible to bacteriophage infections and gene acquisition through various mechanisms of horizontal gene transfer.
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Affiliation(s)
- Florian Tagini
- Institute of Microbiology, Department of Laboratory Medicine, Lausanne University Hospital, Lausanne University, Lausanne, Switzerland
| | - Trestan Pillonel
- Institute of Microbiology, Department of Laboratory Medicine, Lausanne University Hospital, Lausanne University, Lausanne, Switzerland
| | - Antony Croxatto
- Institute of Microbiology, Department of Laboratory Medicine, Lausanne University Hospital, Lausanne University, Lausanne, Switzerland
| | - Claire Bertelli
- Institute of Microbiology, Department of Laboratory Medicine, Lausanne University Hospital, Lausanne University, Lausanne, Switzerland
| | - Angela Koutsokera
- Division of Pulmonology, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Alban Lovis
- Division of Pulmonology, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, Department of Laboratory Medicine, Lausanne University Hospital, Lausanne University, Lausanne, Switzerland
- Division of Infectious Diseases, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
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Rajamani Sekar S, Veeraraghavan B, Anandan S, Devanga Ragupathi N, Sangal L, Joshi S. Strengthening the laboratory diagnosis of pathogenicCorynebacteriumspecies in the Vaccine era. Lett Appl Microbiol 2017; 65:354-365. [DOI: 10.1111/lam.12781] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 07/06/2017] [Accepted: 07/20/2017] [Indexed: 01/06/2023]
Affiliation(s)
- S.K. Rajamani Sekar
- Department of Clinical Microbiology; Christian Medical College; Vellore India
| | - B. Veeraraghavan
- Department of Clinical Microbiology; Christian Medical College; Vellore India
| | - S. Anandan
- Department of Clinical Microbiology; Christian Medical College; Vellore India
| | | | - L. Sangal
- World Health Organization (WHO) Country Office; New Delhi India
| | - S. Joshi
- World Health Organization (WHO) Country Office; New Delhi India
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Sangal L, Joshi S, Anandan S, Balaji V, Johnson J, Satapathy A, Haldar P, Rayru R, Ramamurthy S, Raghavan A, Bhatnagar P. Resurgence of Diphtheria in North Kerala, India, 2016: Laboratory Supported Case-Based Surveillance Outcomes. Front Public Health 2017; 5:218. [PMID: 28913330 PMCID: PMC5582196 DOI: 10.3389/fpubh.2017.00218] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 08/04/2017] [Indexed: 11/13/2022] Open
Abstract
Introduction As part of national program, laboratory supported vaccine preventable diseases surveillance was initiated in Kerala in 2015. Mechanisms have been strengthened for case investigation, reporting, and data management. Specimens collected and sent to state and reference laboratories for confirmation and molecular surveillance. The major objective of this study is to understand the epidemiological information generated through surveillance system and its utilization for action. Methods Surveillance data captured from reporting register, case investigation forms, and laboratory reports was analyzed. Cases were allotted unique ID and no personal identifying information was used for analysis. Throat swabs were collected from investigated cases as part of surveillance system. All Corynebacterium diphtheriae isolates were confirmed with standard biochemical tests, ELEK’s test, and real-time PCR. Isolates were characterized using whole genome-based multi locus sequence typing method. Case investigation forms and laboratory results were recorded electronically. Public health response by government was also reviewed. Results A total of 533 cases were identified in 11 districts of Kerala in 2016, of which 92% occurred in 3 districts of north Kerala; Malappuram, Kozhikode, and Kannur. Almost 79% cases occurred in >10 years age group. In <18 years age group, 62% were male while in ≥18 years, 69% were females. In <10 years age group, 31% children had received three doses of diphtheria vaccine, whereas in ≥10 years, 3% cases had received all doses. Fifteen toxigenic C. diphtheriae isolates represented 6 novel sequence types (STs) (ST-405, ST-408, ST-466, ST-468, ST-469, and ST-470). Other STs observed are ST-50, ST-295, and ST-377. Conclusion Diphtheria being an emerging pathogen, establishing quality surveillance for providing real-time information on disease occurrence and mortality is imperative. The epidemiological data thus generated was used for targeted interventions and to formulate vaccine policies. The data on molecular surveillance have given an insight on strain variation and transmission patterns.
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Affiliation(s)
- Lucky Sangal
- WHO India, World Health Organization, New Delhi, India
| | - Sudhir Joshi
- WHO India, World Health Organization, New Delhi, India
| | - Shalini Anandan
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | | | | | | | - Pradeep Haldar
- Ministry of Health and Family Welfare, Government of India, New Delhi, India
| | - Ramesh Rayru
- Ministry of Health, Government of Kerala, Thiruvananthapuram, India
| | | | - Asha Raghavan
- WHO India, World Health Organization, Thiruvananthapuram, India
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Validation of optimal reference genes for quantitative real time PCR in muscle and adipose tissue for obesity and diabetes research. Sci Rep 2017; 7:3612. [PMID: 28620170 PMCID: PMC5472619 DOI: 10.1038/s41598-017-03730-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022] Open
Abstract
The global incidence of obesity has led to an increasing need for understanding the molecular mechanisms that drive this epidemic and its comorbidities. Quantitative real-time RT-PCR (RT-qPCR) is the most reliable and widely used method for gene expression analysis. The selection of suitable reference genes (RGs) is critical for obtaining accurate gene expression information. The current study aimed to identify optimal RGs to perform quantitative transcriptomic analysis based on RT-qPCR for obesity and diabetes research, employing in vitro and mouse models, and human tissue samples. Using the ReFinder program we evaluated the stability of a total of 15 RGs. The impact of choosing the most suitable RGs versus less suitable RGs on RT-qPCR results was assessed. Optimal RGs differed between tissue and cell type, species, and experimental conditions. By employing different sets of RGs to normalize the mRNA expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), we show that sub-optimal RGs can markedly alter the PGC1α gene expression profile. Our study demonstrates the importance of validating RGs prior to normalizing transcriptional expression levels of target genes and identifies optimal RG pairs for reliable RT-qPCR normalization in cells and in human and murine muscle and adipose tissue for obesity/diabetes research.
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