The dtxR Gene: A New Alternative Marker to Identify Corynebacterium ulcerans and Corynebacterium pseudotuberculosis by PCR Assay

Sunarno, Sunarno; Fitri, Nyoman; Puspandari, Nelly; Sariadji, Kambang

doi:10.18585/inabj.v10i3.403

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…However, the dtxR gene was used in this study, while the aforementioned researchers used the rpoB gene. Previously, we showed that the dtxR gene had some advantages over 16S rRNA and pld genes in identifying C. ulcerans and C. pseudotuberculosis (20). Moreover, we detected and identified three species of diphtheria-causing bacteria, while they only identified two (C. diphtheriae and C. ulcerans/C.…”

Section: Discussionmentioning

confidence: 90%

Development and Application of Dtxr and Tox Genes Targeting Real-time PCR to Identify Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis Simultaneously

Sunarno¹,

Hartoyo²,

Amalia³

et al. 2022

Jundishapur J Microbiol

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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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Section: Discussionmentioning

confidence: 90%

Development and Application of Dtxr and Tox Genes Targeting Real-time PCR to Identify Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis Simultaneously

Sunarno¹,

Hartoyo²,

Amalia³

et al. 2022

Jundishapur J Microbiol

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New approach for the identification of potentially toxigenic Corynebacterium sp. using a multiplex PCR assay

Sunarno

Khariri

Muna

et al. 2021

Journal of Microbiological Methods

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Polymorphisms of dtxR Gene of Corynebacterium diphtheriae Isolated from Diphtheria Outbreak in Indonesia

Wang¹,

Amalia²,

Hartoyo³

et al. 2022

Jundishapur J Microbiol

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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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The dtxR Gene: A New Alternative Marker to Identify Corynebacterium ulcerans and Corynebacterium pseudotuberculosis by PCR Assay

Cited by 3 publications

References 33 publications

Development and Application of Dtxr and Tox Genes Targeting Real-time PCR to Identify Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis Simultaneously

Development and Application of Dtxr and Tox Genes Targeting Real-time PCR to Identify Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis Simultaneously

New approach for the identification of potentially toxigenic Corynebacterium sp. using a multiplex PCR assay

Polymorphisms of dtxR Gene of Corynebacterium diphtheriae Isolated from Diphtheria Outbreak in Indonesia

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