Antimicrobial drug resistance in Corynebacterium diphtheriae mitis.
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ABSTRACT:
SUBMITTER: Barraud O
PROVIDER: S-EPMC3310561 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundCorynebacterium diphtheriae, the agent of diphtheria, is a genetically diverse bacterial species. Although antimicrobial resistance has emerged against several drugs including first-line penicillin, the genomic determinants and population dynamics of resistance are largely unknown for this neglected human pathogen.MethodsHere, we analyzed the associations of antimicrobial susceptibility phenotypes, diphtheria toxin production, and genomic features in C. diphtheriae. We used 247 strains collected over several decades in multiple world regions, including the 163 clinical isolates collected prospectively from 2008 to 2017 in France mainland and overseas territories.ResultsPhylogenetic analysis revealed multiple deep-branching sublineages, grouped into a Mitis lineage strongly associated with diphtheria toxin production and a largely toxin gene-negative Gravis lineage with few toxin-producing isolates including the 1990s ex-Soviet Union outbreak strain. The distribution of susceptibility phenotypes allowed proposing ecological cutoffs for most of the 19 agents tested, thereby defining acquired antimicrobial resistance. Penicillin resistance was found in 17.2% of prospective isolates. Seventeen (10.4%) prospective isolates were multidrug-resistant (≥ 3 antimicrobial categories), including four isolates resistant to penicillin and macrolides. Homologous recombination was frequent (r/m = 5), and horizontal gene transfer contributed to the emergence of antimicrobial resistance in multiple sublineages. Genome-wide association mapping uncovered genetic factors of resistance, including an accessory penicillin-binding protein (PBP2m) located in diverse genomic contexts. Gene pbp2m is widespread in other Corynebacterium species, and its expression in C. glutamicum demonstrated its effect against several beta-lactams. A novel 73-kb C. diphtheriae multiresistance plasmid was discovered.ConclusionsThis work uncovers the dynamics of antimicrobial resistance in C. diphtheriae in the context of phylogenetic structure, biovar, and diphtheria toxin production and provides a blueprint to analyze re-emerging diphtheria.
| S-EPMC7694903 | biostudies-literature
Project description:The genome sequence of the human pathogen Corynebacterium diphtheriae bv. mitis strain ISS 3319 was determined and closed in this study. The genome is estimated to have 2,404,936 bp encoding 2,257 proteins. This strain also possesses a plasmid of 1,960 bp.
| S-EPMC5794954 | biostudies-literature
Project description: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.
| S-EPMC6108181 | biostudies-literature
Project description:Corynebacterium diphtheriae strains , whole genome shotgun sequencing project.2018.Colombia.
| PRJNA650156 | ENA
Project description:Novel nontoxigenic Corynebacterium diphtheriae was isolated from a domestic cat with severe otitis. Contact investigation and carrier study of human and animal contacts yielded 3 additional, identical isolates from cats, although no evidence of zoonotic transmission was identified. Molecular methods distinguished the feline isolates from known C. diphtheriae.
| S-EPMC3321947 | biostudies-literature
Project description:Corynebacterium diphtheriae and Corynebacterium ulcerans are rarely isolated from clinical samples in Belgium. A case of toxigenic C. ulcerans in a woman is described, which confirms that this pathogen is still present. During investigation of the patient's cats, only a non-toxigenic toxin-bearing C. diphtheriae strain was detected.
| S-EPMC4184488 | biostudies-literature
Project description:Corynebacterium diphtheriae bv. mitis str. NC03529 Genome sequencing and assembly
| PRJNA89613 | ENA
Project description:Disulfide-bond formation, mediated by the Dsb family of proteins, is important in the correct folding of secreted or extracellular proteins in bacteria. In Gram-negative bacteria, disulfide bonds are introduced into the folding proteins in the periplasm by DsbA. DsbE from Escherichia coli has been implicated in the reduction of disulfide bonds in the maturation of cytochrome c. The Gram-positive bacterium Mycobacterium tuberculosis encodes DsbE and its homologue DsbF, the structures of which have been determined. However, the two mycobacterial proteins are able to oxidatively fold a protein in vitro, unlike DsbE from E. coli. In this study, the crystal structure of a DsbE or DsbF homologue protein from Corynebacterium diphtheriae has been determined, which revealed a thioredoxin-like domain with a typical CXXC active site. Structural comparison with M. tuberculosis DsbF would help in understanding the function of the C. diphtheriae protein.
| S-EPMC4157413 | biostudies-literature
Project description: Not available
| S-EPMC10699712 | biostudies-literature
Project description:Many pathogenic bacteria, including Escherichia coli and Vibrio cholerae, can become viable but nonculturable (VBNC) following exposure to specific stress conditions. Corynebacterium diphtheriae, a known human pathogen causing diphtheria, has not previously been shown to enter the VBNC state. Here, we report that C. diphtheriae can become VBNC when exposed to low temperatures. Morphological differences in culturable and VBNC C. diphtheriae were examined using scanning electron microscopy. Culturable cells presented with a typical rod-shape, whereas VBNC cells showed a distorted shape with an expanded center. Cells could be transitioned from VBNC to culturable following treatment with catalase. This was further evaluated via RNA sequence-based transcriptomic analysis and reverse-transcription quantitative PCR of culturable, VBNC, and resuscitated VBNC cells following catalase treatment. As expected, many genes showed different behavior by resuscitation. The expression of both the diphtheria toxin and the repressor of diphtheria toxin genes remained largely unchanged under all four conditions (culturable, VBNC, VBNC after the addition of catalase, and resuscitated cells). This is the first study to demonstrate that C. diphtheriae can enter a VBNC state and that it can be rescued from this state via the addition of catalase. This study helps to expand our general understanding of VBNC, the pathogenicity of VBNC C. diphtheriae, and its environmental survival strategy.
| S-EPMC8145655 | biostudies-literature