Draft genome sequence of Turicella otitidis ATCC 51513, isolated from middle ear fluid from a child with otitis media

Metabolism and gene sequence variation in Turicella otitidis implies its adaptability and pathogenicity in extra-otic infection: a systematic review

Turicella otitidis belongs to the Corynebacteriaceae family and is a normal inhabitant of the ear and exists in a commensal relationship with its host. In children, T. otitidis is frequently associated with otitis media. The emergence of Turicella otitidis as a pathogen is concerning, particularly due to the limited availability of data on its pathogenic properties. The objective of this study is to conduct a systematic review of T. otitidis infections occurring in both the ear and other anatomical sites, and to summarize the differences in metabolism and genome sequences between isolates obtained from the ear and blood.

Turicella otitidis: a rare agent causing microbial keratitis

A 10-year-old boy treated for alkali injury with multiple interventions presented with a perforated corneal ulcer with clinically suspected bacterial aetiology. Cornea scraping and tissue adhesive application were planned. During surgery, an eyelash was found embedded at the perforated site. Gram staining of corneal scraping revealed the presence of Gram-positive bacilli on the first day which later was identified as Turicella otitidis with culture followed by VITEK V.2.0 (Biomerieux) identification. The bacterium was found to be sensitive to amikacin, ciprofloxacin, cefazolin, gatifloxacin, moxifloxacin, ofloxacin and vancomycin antibiotics as per Clinical and Laboratory Standards Institute guidelines. Coryneform bacteria is a rare cause of keratitis, and this is the first reported case of microbial keratitis caused by one of the rare corynebacterium species T. otitidis to the best of our knowledge. Literature search does not reveal any specific ocular features typical to this organism. This case supports the growing evidence for pathogenicity of T. otitidis in ocular samples. This study demonstrates the utility of VITEK for the identification of rare pathogen and may facilitate the use of certain antibiotics in the treatment regimen of T. otitidis infections.

Reviewing the Pathogenic Potential of the Otitis-Associated Bacteria Alloiococcus otitidis and Turicella otitidis

Alloiococcus otitidis and Turicella otitidis are common bacteria of the human ear. They have frequently been isolated from the middle ear of children with otitis media (OM), though their potential role in this disease remains unclear and confounded due to their presence as commensal inhabitants of the external auditory canal. In this review, we summarize the current literature on these organisms with an emphasis on their role in OM. Much of the literature focuses on the presence and abundance of these organisms, and little work has been done to explore their activity in the middle ear. We find there is currently insufficient evidence available to determine whether these organisms are pathogens, commensals or contribute indirectly to the pathogenesis of OM. However, building on the knowledge currently available, we suggest future approaches aimed at providing stronger evidence to determine whether A. otitidis and T. otitidis are involved in the pathogenesis of OM. Such evidence will increase our understanding of the microbial risk factors contributing to OM and may lead to novel treatment approaches for severe and recurrent disease.

Phylogeny Trumps Chemotaxonomy: A Case Study Involving Turicella otitidis

The genus Turicella was proposed to harbor clinical strains isolated from middle-ear fluids of patients with otitis media. 16S rRNA phylogeny showed that it belonged to the mycolic acid-containing actinobacteria, currently classified in the order Corynebacteriales, and was closely related to the genus Corynebacterium. A new genus was proposed for the organisms as unlike corynebacteria they lacked mycolic acids and had different menaquinones. Here, we carried out large-scale comparative genomics on representative strains of the genera Corynebacterium and Turicella to check if this chemotaxonomic classification is justified. Three genes that are known to play an essential role in mycolic acid biosynthesis were absent in Turicella and two other mycolate-less Corynebacterium spp., explaining the lack of mycolic acids resulted from the deletion of genes and does not confer any phylogenetic context. Polyphasic phylogenetic analyses using 16S rRNA, bacterial core genes and genes responsible for synthesizing menaquinones unequivocally indicate that Turicella is a true member of the genus Corynebacterium. Here, we demonstrate that menaquinone and mycolic acid that have been used as critical taxonomic markers should be interpreted carefully, particularly when genome-based taxonomy is readily available. Based on the phylogenetic analysis, we propose to reclassify Turicella otitidis as Corynebacterium otitidis comb. nov.

Draft Genome Sequence of Turicella otitidis TD1, Isolated from a Patient with Bacteremia

We report the draft genome sequence of Turicella otitidis strain TD1, isolated from a central line catheter sample from a patient with a history of bowel obstruction. It contained several genetic determinants of multidrug-resistant phenotypes such as a cfrA 50S methyltransferase, two major facilitator superfamily-type drug resistance transporters, and a putative beta-lactamase.

The quest for a unified view of bacterial land colonization

Exploring molecular mechanisms underlying bacterial water-to-land transition represents a critical start toward a better understanding of the functioning and stability of the terrestrial ecosystems. Here, we perform comprehensive analyses based on a large variety of bacteria by integrating taxonomic, phylogenetic and metagenomic data, in the quest for a unified view that elucidates genomic, evolutionary and ecological dynamics of the marine progenitors in adapting to nonaquatic environments. We hypothesize that bacterial land colonization is dominated by a single-gene sweep, that is, the emergence of dnaE2 derived from an early duplication event of the primordial dnaE, followed by a series of niche-specific genomic adaptations, including GC content increase, intensive horizontal gene transfer and constant genome expansion. In addition, early bacterial radiation may be stimulated by an explosion of land-borne hosts (for example, plants and animals) after initial land colonization events.