Carriage of a Single Strain of Nontoxigenic Corynebacterium diphtheriae bv. Belfanti ( Corynebacterium belfantii ) in Four Patients with Cystic Fibrosis

Abstract

Cystic fibrosis (CF) patients are commonly colonized by bacterial pathogens, which can induce persistent lung inflammation and may contribute to clinical deterioration. Colonization of CF patients and cross-transmission by Corynebacterium diphtheriae have not been reported so far. The aim of this article was to investigate the possibility of a cross-transmission of C. diphtheriae biovar Belfanti between four patients of a CF center. C. diphtheriae biovar Belfanti (now formally called C. belfantii) isolates were collected from four patients in a single CF care center over a period of 6 years and analyzed by microbiological methods and whole-genome sequencing. Epidemiological links among patients were investigated. Ten isolates were collected from 4 patients. Whole-genome sequencing of one isolate from each patient showed that a single strain was shared among them. In addition, one patient was found to have the same strain in two consecutive samplings performed 9 months apart. The strain was nontoxigenic and was susceptible to most antimicrobial agents. Ciprofloxacin resistance was observed in one patient. The idea of transmission of the strain among patients was supported by the occurrence of same-day visits to the CF center. This study demonstrated colonization of CF patients by C. diphtheriae biovar Belfanti (C. belfantii), and the data suggest persistence and transmission of a unique strain during at least 6 years in a single CF patient care center.

Whole-Genome Sequencing of Corynebacterium diphtheriae Isolates Recovered from an Inner-City Population Demonstrates the Predominance of a Single Molecular Strain

“…Our study is novel in that it is the first study, to our knowledge, to whole-genome sequence a large collection of C. diphtheriae isolates collected in North America. Previous groups have sequenced collections of C. diphtheriae from Germany, Belarus, South Africa, and Australia (2,7,9,(11)(12)(13)(14)(15). Interestingly, our dominant sequence type, ST76, has only been reported in PubMLST.org, an MLST database, in 9 isolates from Saint Petersburg, Russia, spanning the years 2005 to 2010.…”

“…WGS also provides the ability to search for virulence factors such as diphtheria toxin and antimicrobial resistance markers. WGS had been used to elucidate transmission dynamics of C. diphtheriae previously (2,7,9,(11)(12)(13)(14)(15) and has shown that unrelated C. diphtheriae genomes differ by approximately 30,000 SNPs or more, whereas epidemiologically linked outbreak isolates differ by up to 150 SNVs (9,12). Similarly, unrelated isolates have been found to be more than 1,000 alleles different when using cgMLST analysis, whereas related isolates have been within 5 alleles (12).…”

Population genomics and antimicrobial resistance in Corynebacterium diphtheriae

“…In addition, we demonstrate an association between alterations in chromosomally encoded targets and phenotypic resistance for quinolone, trimethoprim, and rifampicin. Fluoroquinolone resistance was previously linked to mutations in the gyrA gene in C. amycolatum [77], C. striatum [78], and C. belfantii [79] but seemingly never for C. diphtheriae. Finally, we demonstrate the co-occurrence within some strains of multiple resistance determinants and uncover a previously undescribed large resistance plasmid in C. diphtheriae.…”

Citizen-science based study of the oral microbiome in Cystic fibrosis and matched controls reveals major differences in diversity and abundance of bacterial and fungal species

“…This genus can work to neutralize acidic conditions that damage teeth [140] and Kingella is acidogenic [141], so their co-occurrence in the CF network may indicate that they complement each other in the acidic CF oral cavity. The association between Corynebacterium and Selenomonas in CF is reasonable, as both have been implicated in CF [142][143][144].…”