Corynebacterium canis sp. nov., isolated from a wound infection caused by a dog bite

Species-level characterization of saliva and dental plaque microbiota reveals putative bacterial and functional biomarkers of periodontal diseases in dogs

Periodontal diseases are among the most common bacterial-related pathologies affecting the oral cavity of dogs. Nevertheless, the canine oral ecosystem and its correlations with oral disease development are still far from being fully characterized. In this study, the species-level taxonomic composition of saliva and dental plaque microbiota of 30 healthy dogs was investigated through a shallow shotgun metagenomics approach. The obtained data allowed not only to define the most abundant and prevalent bacterial species of the oral microbiota in healthy dogs, including members of the genera Corynebacterium and Porphyromonas, but also to identify the presence of distinct compositional motifs in the two oral microniches as well as taxonomical differences between dental plaques collected from anterior and posterior teeth. Subsequently, the salivary and dental plaque microbiota of 18 dogs affected by chronic gingival inflammation and 18 dogs with periodontitis were compared to those obtained from the healthy dogs. This analysis allowed the identification of bacterial and metabolic biomarkers correlated with a specific clinical status, including members of the genera Porphyromonas and Fusobacterium as microbial biomarkers of a healthy and diseased oral status, respectively, and genes predicted to encode for metabolites with anti-inflammatory properties as metabolic biomarkers of a healthy status.

Microbial Complexity of Oral Cavity of Healthy Dogs Identified by Mass Spectrometry and Next-Generation Sequencing

The high complexity of the oral microbiota of healthy dogs and the close exposure of humans to companion animals represent a risk of the transmission of potential zoonotic microorganisms to humans, especially through dog bites, including multidrug-resistant ones. Nonetheless, a limited number of comprehensive studies have focused on the diversity of the microorganisms that inhabit the oral cavities of healthy dogs, particularly based on modern molecular techniques. We investigated bacterial and fungal organisms in the oral cavities of 100 healthy dogs based on a combination of conventional and selective microbiological culture, mass spectrometry (MALDI-TOF MS), and next-generation sequencing. In addition, in vitro antimicrobial susceptibility patterns of isolates and mecA resistance gene were assessed. A total of 213 bacteria and 20 fungi were isolated. Staphylococcus pseudintermedius (40/100 = 40%), α-hemolytic Streptococcus (37/100 = 37%), and Pasteurella stomatis (22/100 = 22%) were the most prevalent bacteria diagnosed by microbiological culture and MALDI-TOF MS, whereas Aspergillus (10/100 = 10%) was the most common fungi identified. Based on next-generation sequencing of selected 20 sampled dogs, Porphyromonas (32.5%), Moraxella (16.3%), Fusobacterium (12.8%), Conchiformibius (9.5%), Bergeyella (5%), Campylobacter (3.8%), and Capnocytophaga (3.4%) genera were prevalent. A high multidrug resistance rate was observed in Staphylococcus pseudintermedius isolates, particularly to azithromycin (19/19 = 100%), penicillin (15/19 = 78.9%), and sulfamethoxazole/trimethoprim (15/19 = 78.9%). In addition, the mecA resistance gene was detected in 6.1% (3/49) of coagulase-positive staphylococci. Here, we highlight the microbial complexity of the oral mucosa of healthy dogs, including potential zoonotic microorganisms and multidrug-resistant bacteria, contributing with the investigation of the microbiota and antimicrobial resistance patterns of the microorganisms that inhabit the oral cavity of healthy dogs.

Influence of Gallic Acid-Containing Mouth Spray on Dental Health and Oral Microbiota of Healthy Dogs: A Pilot Study

The pilot study aimed to investigate the effects of GAMS on oral microbiota in healthy dog subjects. Thirty-eight dogs were recruited and randomly allocated to the placebo (n = 19) and treatment groups (n = 19). The dogs were treated with mouth spray once daily for 42 days. The changes in the gingival index (GI), plaque index (PI), and calculus index (CI) were measured at baseline (day 0) and end of the study (42nd day). The changes in the oral microbial composition of representative dogs (placebo, n = 7; and treatment, n = 7) were also evaluated at baseline and end of the study. Oral microbial composition was assessed by sequencing. The sequences were annotated using the QIIME 2.0^TM. The GI, PI, and CI indexes were reduced after the GAMS usage. The abundance of the commensal bacterial phylum Actinobacteria and Chloroflexi, genera Frederiksenia, and Bergeyella was improved after six weeks of GAMS usage. GAMS reduced the pathogenic bacterial species, including Neisseria sp., Desulfobulbus sp., Capnocytophaga canis, and Corynebacterium mustelae. Moreover, some pathogenic bacterial abundances were increased at the end of the study. All the microbial variations were observed within the group. The inter-group analysis revealed that the changes were unrelated to GAMS usage. Further studies need to be carried out using more experimental subjects to confirm the effectiveness of GAMS. More metagenomic data are required to evidence the GMAS impact on the oral microbiome of healthy dogs.

Corynebacterium antarcticum sp. nov., Corynebacterium marambiense sp. nov., Corynebacterium meridianum sp. nov., and Corynebacterium pygosceleis sp. nov., isolated from Adélie penguins (Pygoscelis adeliae)

A taxonomic study was conducted on 16 bacterial strains isolated from wild Adélie penguins (Pygoscelis adeliae) from Seymour (Marambio) Island and James Ross Island. An initial screening by repetitive sequence-based PCR fingerprinting divided the strains studied into four coherent groups. Phylogenetic analysis based on 16S rRNA gene sequences assigned all groups to the genus Corynebacterium and showed that Corynebacterium glyciniphilum and Corynebacterium terpenotabidum were the closest species with 16S rRNA gene sequence similarities between 95.4 % and 96.5 %. Further examination of the strains studied with ribotyping, MALDI-TOF mass spectrometry, comprehensive biotyping and calculation of average nucleotide identity and digital DNA-DNA hybridisation values confirmed the separation of the four groups from each other and from the other Corynebacterium species. Chemotaxonomically, the four strains P5828^T, P5850^T, P6136^T, P7210^T representing the studied groups were characterised by C_16:0 and C_18:1ω9c as the major fatty acids, by the presence of meso-diaminopimelic acid in the peptidoglycan, the presence of corynemycolic acids and a quinone system with the predominant menaquinone MK-9(H₂). The results of this study show that the strains studied represent four new species of the genus Corynebacterium, for which the names Corynebacterium antarcticum sp. nov. (type strain P5850^T = CCM 8835^T = LMG 30620^T), Corynebacterium marambiense sp. nov. (type strain P5828^T = CCM 8864^T = LMG 31626^T), Corynebacterium meridianum sp. nov. (type strain P6136^T = CCM 8863^T = LMG 31628^T) and Corynebacterium pygosceleis sp. nov. (type strain P7210^T = CCM 8836^T = LMG 30621^T) are proposed.

In Silico Prediction and Analysis of Unusual Lantibiotic Resistance Operons in the Genus Corynebacterium

Post-translationally modified, (methyl-)lanthionine-containing peptides are produced by several Gram-positive bacteria. These so-called lantibiotics have potent activity against various bacterial pathogens including multidrug-resistant strains and are thus discussed as alternatives to antibiotics. Several naturally occurring mechanisms of resistance against lantibiotics have been described for bacteria, including cell envelope modifications, ABC-transporters, lipoproteins and peptidases. Corynebacterium species are widespread in nature and comprise important pathogens, commensals as well as environmentally and biotechnologically relevant species. Yet, little is known about lantibiotic biosynthesis and resistance in this genus. Here, we present a comprehensive in silico prediction of lantibiotic resistance traits in this important group of Gram-positive bacteria. Our analyses suggest that enzymes for cell envelope modification, peptidases as well as ABC-transporters involved in peptide resistance are widely distributed in the genus. Based on our predictions, we analyzed the susceptibility of six Corynebacterium species to nisin and found that those without dedicated resistance traits are more susceptible and unable to adapt to higher concentrations. In addition, we were able to identify lantibiotic resistance operons encoding for peptidases, ABC-transporters and two-component systems with an unusual predicted structure that are conserved in the genus Corynebacterium. Heterologous expression shows that these operons indeed confer resistance to the lantibiotic nisin.

Complete Genome Sequence of the Type Strain Corynebacterium mustelae DSM 45274, Isolated from Various Tissues of a Male Ferret with Lethal Sepsis

The complete genome of Corynebacterium mustelae DSM 45274 comprises 3,474,226 bp and 3,188 genes. Prominent niche and virulence factors are SpaBCA- and SpaDEF-type pili with similarity to pilus proteins of Corynebacterium resistens and Corynebacterium urealyticum and an immunomodulatory EndoS-like endoglycosidase probably catalyzing the removal of distinct glycans from IgG antibodies.

Complete Genome Sequence of the Type Strain Corynebacterium epidermidicanis DSM 45586, Isolated from the Skin of a Dog Suffering from Pruritus

The complete genome sequence of Corynebacterium epidermidicanis DSM 45586 comprises 2,692,072 bp with 58.06% G+C content. The annotation revealed 2,466 protein-coding regions, including genes for surface-anchored proteins with Cna B-type or bacterial Ig-like domains and for an adhesive SpaABC-type pilus with similarity to fimbrial subunits of Corynebacterium resistens DSM 45100.

Corynebacterium pelargi sp. nov., isolated from the trachea of white stork nestlings

A Gram-stain-positive, pleomorphic, oxidase-negative, non-motile isolate from the trachea of a white stork from Poland, designated strain 136/3T, was subjected to a comprehensive taxonomic investigation. A comparative analysis of the 16S rRNA gene sequence showed highest similarities to Corynebacterium mustelae , Corynebacterium pseudotuberculosis , Corynebacterium vitaeruminis and Corynebacterium ulcerans (96.0–96.3 %). The quinone system consisted of major amounts of MK-8(H2), minor amounts of MK-9(H2) and traces of MK-8 and MK-9. The polar lipid profile of strain 136/3T contained phosphatidylinositol and phosphatidylinositol-mannoside as major lipids and phosphatidylglycerol and an acidic glycolipid in moderate amounts. In addition small amounts of diphosphatidylglycerol, a phospholipid, an aminolipid and two lipids of unknown group affiliation were found. The polyamine pattern was composed of the major components spermidine and spermine. Putrescine, 1,3-diaminopropane, cadaverine, sym-homospermidine and tyramine were found in minor or trace amounts. The diamino acid of the peptidoglycan was meso-diaminopimelic acid. In the fatty acid profile straight-chain, saturated and mono-unsaturated fatty acids predominated (C18 : 1ω9c, C16 : 1ω7c, C16 : 0, C18  : 0). Corynemycolic acids were detected. Physiological traits as well as unique traits of the polar lipid profile and the fatty acid pattern distinguished strain 136/3T from the most closely related species. All these results indicate that strain 136/3T represents a novel species of the genus Corynebacterium for which we propose the name Corynebacterium pelargi sp. nov. The type strain is 136/3T ( = CIP 110778T = CCM 8517T = LMG 28174T).

Cutaneous abscess caused by Corynebacterium lactis in a companion dog

Many new, emerging and re-emerging diseases of humans are caused by pathogens which originate from animals or products of animal origin. Corynebacterium lactis, a recently described species of the genus Corynebacterium, was first isolated from milk of asymptomatic cows. In the present study a cutaneous abscess caused by C. lactis in a dog was recognized by cytologic and histologic examination in addition to 16S rRNA gene analysis of the microorganism. Therefore, C. lactis should be included among other bacterial species recognized as emerging pathogens for companion animals.

Corynebacterium epidermidicanis sp. nov., isolated from skin of a dog

A Gram-stain-positive, pleomorphic, oxidase-negative, non-motile isolate from the skin of a dog, designated strain 410(T), was subjected to comprehensive taxonomic characterization. Comparison of the 16S rRNA gene sequences revealed that the novel isolate showed highest similarities to the type strains of Corynebacterium humireducens, Corynebacterium diphtheriae, Corynebacterium pseudotuberculosis and Corynebacterium ulcerans (96.1-96.8 %). The quinone system consisted predominantly of MK-8(H(2)) and MK-9(H(2)). The polar lipid profile of strain 410(T) contained the major compounds diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified phospholipids and four unidentified glycolipids. The polyamine pattern was composed of the major amines spermidine and spermine. In the fatty acid profile, predominantly straight-chain, saturated and mono-unsaturated fatty acids were detected (C(18 : 1)ω9c, C(16 : 1)ω7c, C(16 : 0)). These chemotaxonomic traits are in agreement with those reported for representatives of the genus Corynebacterium. Strain 410(T) tested negative for diphtheria toxin. Physiological properties as well as unique traits in the polar lipid profile could be used to distinguish strain 410(T) from the most closely related species. These data suggest that strain 410(T) represents a novel species of the genus Corynebacterium, for which we propose the name Corynebacterium epidermidicanis sp. nov. The type strain is 410(T) (= DSM 45586(T) = LMG 26322(T) = CCUG 60915(T)).