Human case of bacteremia caused by Streptococcus canis sequence type 9 harboring the scm gene

Genetic organization of an M protein trans-acting positive regulator (Mga) orthologue and its adjacent M-like protein (SCM) alleles in Streptococcus canis

OBJECTIVE

The purpose of this study was to identify the M protein trans-acting positive regulator (Mga) orthologue and its adjacent M-like protein (SCM) alleles in Streptococcus canis.

RESULTS

Using the 39 SCM allele isolates and polymerase chain reaction-based amplification and sequencing, we obtained the deduced Mga amino acid (AA) sequences. The 22 Mga sequences in whole-genome sequences were obtained by searching the National Collection of Type Cultures 12,191(T) Mga sequence into the database. The percentage identity to the type-strain Mga sequence was examined along with its size. The presence of the Mga-specific motifs was confirmed. Of the 62 strains, we identified 59 Mga sequences with an AA size of 509 (except for four different sizes). Percentage identity ranged from 96.66 to 100% with the confirmed Mga-specific motifs and diverse SCM allele populations. Our findings support the presence of an Mga orthologue and diverse SCM allele populations.

Streptococcus canis Native Aortic Valve Endocarditis Linked to Cat Exposure: A Case Report and Review

Streptococcus canis is an uncommon human pathogen, but documented infections have been mostly associated with exposure to dogs. There are only five documented cases of endocarditis secondary to streptococcus canis, with all cases except one documenting exposure to a canine. We present a 74-year-old male with a history of Type 2 diabetes mellitus, CKD 3, moderate aortic stenosis and remote exposure to agent orange, who was found to have Streptococcus canis native valve endocarditis without exposure to a dog. To the best of our knowledge this case is the first case of endocarditis linked to feline exposure.

The type-2 Streptococcus canis M protein SCM-2 binds fibrinogen and facilitates antiphagocytic properties

Streptococcus canis is a zoonotic agent that causes severe invasive diseases in domestic animals and humans, but little is known about its pathogenesis and virulence mechanisms so far. SCM, the M-like protein expressed by S. canis, is considered one of the major virulence determinants. Here, we report on the two distinct groups of SCM. SCM-1 proteins were already described to interact with its ligands IgG and plasminogen as well as with itself and confer antiphagocytic capability of SCM-1 expressing bacterial isolates. In contrast, the function of SCM-2 type remained unclear to date. Using whole-genome sequencing and subsequent bioinformatics, FACS analysis, fluorescence microscopy and surface plasmon resonance spectrometry, we demonstrate that, although different in amino acid sequence, a selection of diverse SCM-2-type S. canis isolates, phylogenetically representing the full breadth of SCM-2 sequences, were able to bind fibrinogen. Using targeted mutagenesis of an SCM-2 isolate, we further demonstrated that this strain was significantly less able to survive in canine blood. With respect to similar studies showing a correlation between fibrinogen binding and survival in whole blood, we hypothesize that SCM-2 has an important contribution to the pathogenesis of S. canis in the host.

Antibiotic-resistant status and pathogenic clonal complex of canine Streptococcus canis-associated deep pyoderma

Background

Streptococcus canis causes deep pyoderma in canines, which raises concerns about the risk of isolates from lesions acquiring an antibiotic-resistant phenotype. It is necessary to identify effective antibiotics and the characteristics of the pathogenic cluster for S. canis-associated deep pyoderma.

Results

The signalment, molecular typing, and antibiotic-resistant status of S. canis isolated from deep pyoderma lesions (27 strains) and oral cavities (26 strains) were analyzed. Older dogs tended to have S. canis-associated deep pyoderma (15 of 27 dogs over 10 years old). Veterinarians chose quinolones for 10/16 cases (63%), even though the rate of quinolone-resistant strains of S. canis is 38–59%. Although 70% of the strains showed resistance to three or more antibiotic classes (37/53), 94% (50/53) strains showed sensitivity for penicillins. We also identified β-lactamase activity among penicillin-resistant strains of S. canis. Clonal complex 13 (CC13) was detected only in lesions and formed independent clusters in the phylogenetic tree. One strain of CC13 was resistant to the anti-methicillin-resistant Staphylococcus aureus drugs, vancomycin and linezolid.

Conclusion

Although antibiotic-resistant strains of S. canis are isolated at a high rate, they can currently be treated with β-lactamase-inhibiting penicillins. CC13 may be a pathogenic cluster with high levels of antibiotics resistance.

Tetracycline, Macrolide and Lincosamide Resistance in Streptococcus canis Strains from Companion Animals and Its Genetic Determinants

Growing antimicrobial resistance (AMR) in companion-animal pathogens, including Streptococcus canis (S. canis), is a significant concern for pet treatment as well for public health. Despite the importance of S. canis in veterinary and human medicine, studies concerning the AMR of this bacterium are still scarce. A total of 65 S. canis strains, isolated from dogs and cats, were assessed to test for susceptibility to six clinically relevant antimicrobials via a microdilution method. The prevalence of the selected acquired-resistance genes was also investigated via PCR. High MIC50 and MIC90 values (≥128 μg/mL) were noted for tetracycline, erythromycin and clindamycin. Only a few strains were resistant to the tested beta-lactams (6.2%). Tetracycline resistance was found in 66.2% of the strains. Resistance to erythromycin and clindamycin (ML resistance) was found in 55.4% of the strains. Strains with a phenotype showing concurrent resistance to tetracycline and ML were predominant (53.8%). AMR in the tested S. canis strains was associated with a variety of acquired and potentially transferable genes. Tetracycline resistance was conferred by tet(O) (40.0%), tet(M) (9.2%), and tet(T) (1.5%), which is reported for the first time in S. canis. In most cases, the tet(M) gene was detected in relation to the conjugative transposon Tn916. The MLSB phenotype was confirmed in the strains harboring erm(B) (43.1%) and erm(TR) (7.7%). To conclude, a high rate of S. canis strains occurring in dogs and cats displayed resistance to antimicrobials important for treatment; moreover, they are a potential reservoirs of various resistance determinants. Therefore, AMR in these pathogens should be continuously monitored, especially regarding the One Health concept.

Genotypic and phenotypic features of eye-origin Streptococcus canis isolates from dogs in 2021: relatedness with clonal complex 46 and antimicrobial resistance

Eye (including cornea) and ear canal are major sources of Streptococcus canis in companion animal practice. We aimed to clarify genotypic and phenotypic features of the eye-origin isolates in 2021 compared to ear-origin isolates in 2021 and eye-origin isolates in 2017. Of the 102 isolates in 2021, nine eye-origin isolates were enrolled, whereas twenty-one ear-origin isolates in 2021 and thirteen eye-origin isolates in 2017 were included as controls. Genotypic analyses included virulence-associated gene (VAG; inl, sagA, slo, scp, lbp, fbp, gbp, ap1, fp1, and brp) profiling, S. canis M-like protein (SCM) allele typing, multilocus sequence typing, and antimicrobial resistance (AMR) genotyping: phenotypic analyses contained hemolytic activity (HA) measurement and AMR phenotyping. There was only one 2017-eye-origin isolate with high-level HA, while the others showed low-level HA. We observed no association of the 2021-eye-origin population with detection rate of each VAG. There was no association of the 2021-eye-origin population with main SCM allele 2. We found significant association of the 2021-eye-origin population with main clonal complex (CC) 46 containing sequence type (ST) 46/ST2. There was significant association of the 2021-eye-origin population with AMR phenotypes/genotypes. Our observations suggest the unique microbiological features (CC46 having AMR phenotypes/genotypes) among the 2021-eye-origin population.

A case of Streptococcus canis bacteremia, osteomyelitis, sacroiliitis, myositis, and abscess

Background

Streptococcus canis is a group G beta-hemolytic Streptococcus species which normally resides on the skin and mucosal surfaces of dogs. Although it rarely causes infection in humans, our case and review of relevant literature demonstrate that this multi-host pathogen may be responsible for metastatic infection. We present an appropriate management strategy in such cases.

Case presentation

A previously healthy 26-year-old male presented to the emergency department with a 2-day history of erythema, pain, and swelling of the left ankle and foot, consistent with acute cellulitis. The patient was initially discharged home with a plan to complete a course of IV cefazolin as an outpatient, but later recalled after two sets of blood cultures grew gram positive cocci. Blood cultures speciated as Streptococcus canis. This was performed by identifying beta hemolytic strep on blood agar, then typed as Lancefield group G, followed by MALDI-TOF which distinguished S. canis. History was unremarkable except for a 2-week history of lower back pain precipitated by a wrestling injury. There was no canine bite or scratch wound, although the patient lives with a dog. CT spine was obtained which demonstrated right piriformis myositis and S1 osteomyelitis. MRI additionally demonstrated right erector spinae myositis, right sacroiliitis, and multiple collections in the right posterior paraspinal soft tissues. Transthoracic echocardiogram did not demonstrate valvular vegetations. The S. canis isolate was pan-susceptible and the patient was ultimately discharged home and completed a 8-week course of IV penicillin G. After completion of therapy, his symptoms, repeat imaging, and biochemical markers suggested resolution of infection on follow-up.

Conclusions

We suggest that management of S. canis bacteremia should involve consideration of screening for metastatic infection and infectious diseases consultation. However, despite its potential for systemic involvement, S. canis is often susceptible to narrow spectrum antibiotics, and may be treated with penicillins.

S. canis does not require a clear portal of entry to cause infection

When S. canis infection is identified, screening for sites of metastatic infection should be considered

S. canis infection is typically susceptible to narrow-spectrum antibiotics

SARS-CoV-2 and Prevotella spp.: friend or foe? A systematic literature review

During this global pandemic of the COVID-19 disease, a lot of information has arisen in the media and online without scientific validation, and among these is the possibility that this disease could be aggravated by a secondary bacterial infection such as Prevotella, as well as the interest or not in using azithromycin, a potentially active antimicrobial agent. The aim of this study was to carry out a systematic literature review, to prove or disprove these allegations by scientific arguments. The search included Medline, PubMed, and Pubtator Central databases for English-language articles published 1999-2021. After removing duplicates, a total of final eligible studies (n=149) were selected. There were more articles showing an increase of Prevotella abundance in the presence of viral infection like that related to Human Immunodeficiency Virus (HIV), Papillomavirus (HPV), Herpesviridae and respiratory virus, highlighting differences according to methodologies and patient groups. The arguments for or against the use of azithromycin are stated in light of the results of the literature, showing the role of intercurrent factors, such as age, drug consumption, the presence of cancer or periodontal diseases. However, clinical trials are lacking to prove the direct link between the presence of Prevotella spp. and a worsening of COVID-19, mainly those using azithromycin alone in this indication.

Comparative genomic features of Streptococcus canis based on the pan-genome orthologous group analysis according to sequence type

Using bacterial pan-genome obtained through whole genome sequencing (WGS), coding DNA sequences (CDSs) can be clustered into pan-genome orthologous groups (POGs). We aimed to investigate comparative genomic features of Streptococcus canis based on POG analysis and to determine CDSs specific to prevalent sequence type (ST) 9. Twenty WGS datasets on S. canis strains from invasive and non-invasive specimens were retrieved from the National Center for Biotechnology Information Assembly database. Based on the WGS data, we performed comparative genome hybridization (CGH), pan- and core-genome prediction, Venn diagram test with five ST9 strains, and phylogenetic analysis, with ST determination. We compared the CDSs between seven ST9 and 13 non-ST9 strains. We observed genomic diversity based on CGH and Venn diagram. The predicted pan- and core-genomes contained 4,772 and 1,403 genes, respectively. We found five clades consisting of different STs (ST1, ST44/2, ST13/14, ST21/15/41, and ST9) based on phylogenetic tree. There were differences in four pathways (DNA restriction-modification system, DNA-mediated transposition, extracellular region, and response to oxidative stress) regulated by CDSs specific to ST9. Our findings describe genomic diversity in CGH and Venn diagram, pan- and core-genomes, five clades of genomes consisting of different STs, and unique CDS features associated to ST9.

Characterization of the Variables Related to Reports of Death Due to Canine Bites in Scientific Articles during the Years 2013-2017: A Systematic Review

Simple Summary

Dog bites are a major public health problem throughout the world. The main consequences for human health include physical and psychological injuries of varying proportions, secondary infections, sequelae, risk of transmission of zoonoses and surgery, among others, which entail costs for the health care system and those affected. The objective of this review was to search and analyze the indexed scientific literature on canine bites resulting in death, published during the period 2013–2017. The results show that most of the articles on bite accidents resulting in death analyzed in this study have details about the victims, their injuries and the treatment received by the victim. These results reflect that most of these accidents are suffered by adults, in public spaces and by only one animal. The analysis of these antecedents, as well as others incorporated in this review, will be of great help to fully understand the incidents of dog bites resulting in death published in the scientific literature.

Abstract

Canine bites are an important public health problem, with consequences such as physical injuries, psychological trauma, transmission of zoonoses, infections and they can even cause death. To avoid deaths caused by this type of bite, multiple factors related to this issue must be considered. The objective of this review was to search and analyze the indexed scientific literature on canine bites resulting in death, published during the period 2013–2017. A search was carried out in various databases of indexed literature, in Spanish and English. After selecting and excluding items using PRISMA, they were classified according to SIGN guidelines to filter out the level of evidence and potential biases. Thirty-three scientific articles were retrieved and analyzed. In most of these, victims between 50 and 64 years of age (28.6%, 8/28) were registered. Additionally, in most of the articles, only one animal participated (80%, 16/20). The highest number of events occurred in public spaces (58.5%, 7/12). In conclusion, most of the scientific articles that report incidents of dog bites resulting in death, provide details about the victims, their injuries and the treatment received; however, few articles provide background information on the context of the attack and the biting animal.

Cultivable bacterial diversity of the canine dental plaque as a potential source of bacterial infections

Dental diseases are a persistent problem, not only in humans, but very often in companion animals as well. Aetiological agents of these diseases are the dental plaque bacteria. In the present study, we focused on identifying cultivable bacteria living in the dental plaque of dogs, specifically dogs suffering from the early stages of periodontal disease. Canine oral bacteria pose a risk to humans that get bitten by the dog, but they also have a zoonotic potential. Dental plaque samples were taken from five dogs of small breeds. Samples were cultured under aerobic and anaerobic conditions on several types of microbiological agars. All obtained and selected bacterial colonies were identified by PCR with universal primers for the 16S rRNA gene and the sequences of the 16S rRNA gene were compared with the sequences available in the GenBank database using BLASTn analysis. A total of 75 bacteria belonging to five phyla, predominantly to Firmicutes and Proteobacteria, were identified. The most frequent species was Pasteurella canis which was detected in all samples. In addition, representatives of the genera Actinomyces, Bacillus, Bacteroides, Corynebacterium, Frederiksenia, Fusobacterium, Haemophilus, Lactobacillus, Leucobacter, Neisseria, Ottowia, Porphyromonas, Pseudomonas, Staphylococcus, Stenotrophomonas and Streptococcus were detected in the samples. In the present study, a broad spectrum of bacteria in dental plaque samples, including canine periodontal pathogens such as Porphyromonas gulae or Porphyromonas macacae were identified. In addition, highly pathogenic bacteria, specifically Actinomyces hordeovulneris, Bacillus circulans, and Bacteroides pyogenes, which pose a serious risk to human health, were detected in samples.

Biofilm production ability and other microbiological features of Streptococcus canis

This study assessed biofilm production ability (BPA) and other microbiological features of Streptococcus canis strains. Companion animal-origin 40 strains from each year (2015/2017) were randomly selected with the host information, and three blood-origin strains from 2 humans/1 dog were included. We measured BPA using crystal violet staining, along with S. canis M-like protein (SCM) allele typing, sequence type (ST) determination, antimicrobial resistance (AMR) phenotyping/genotyping, and virulence-associated gene profiling (gbp-ap1-fp1-brp). BPA measurements revealed that 35 strains with BPA and 48 strains without BPA. There was association of the producer with isolation year (2017). We found association between the non-producer and SCM allele 1/ST9: there was association of the producer with SCM allele 10/ST21. We observed correlation between the producer and presence of AMR genotypes. There was association between the producer and ap1 detection and between non-producer and gbp detection. Our observations suggest the correlation between the producer and other microbiological features (isolation year/SCM allele type 10/ST21/presence of AMR genotypes/ap1 detection).

Pathogenicity and drug resistance of animal streptococci responsible for human infections

Bacteria of the genus Streptococcus, earlier considered typically animal, currently have also been causing infections in humans. It is necessary to make clinicians aware of the emergence of new species that may cause the development of human diseases. There is an increasing frequency of isolation of streptococci such as S. suis, S. dysgalactiae, S. iniae and S. equi from people. Isolation of Streptococcus bovis/Streptococcus equinus complex bacteria has also been reported. The streptococcal species described in this review are gaining new properties and virulence factors by which they can thrive in new environments. It shows the potential of these bacteria to changes in the genome and the settlement of new hosts. Information is presented on clinical cases that concern streptococcus species belonging to the groups Bovis, Pyogenic and Suis. We also present the antibiotic resistance profiles of these bacteria. The emerging resistance to β-lactams has been reported. In this review, the classification, clinical characteristics and antibiotic resistance of groups and species of streptococci considered as animal pathogens are summarized.

Systematic Review: Comparison of the Main Variables of Interest in Publications of Canine Bite Accidents in the Written Press, Gray and Scientific Literature in Chile and Spain, between the Years 2013 and 2017

Simple Summary

Dog bites are a major public health problem throughout the world. The different types of information sources that exist in relation to this issue are influencing decision making to control and prevent these incidents. For this reason, the present study aims to compare the main variables of interest in the publications of dog bite accidents in the written and grey press and scientific literature in Chile and Spain, between 2013 and 2017. The results showed that sensationalist variables in dog bite articles are reported more frequently in the press literature compared to the indexed and grey literature. Examples of these variables are involvement of potentially dangerous breeds, articles with death reports, among others. In conclusion, an improvement in the quality of the information that reaches the population about dog bites could be achieved through better and more fluid communication between scientists and journalists who publish on this topic.

Abstract

Dog bites are a major public health problem, with consequences such as physical injury, psychological trauma, transmission of zoonoses, infections, and economic costs. For this reason, it is necessary to develop preventive programs, which require quality information to support the authorities’ decision-making and to raise public awareness about the application of the proposed measures. The objective of this review was to analyze the press, indexed and gray dog bite literature published during the 2013–2017 period. During that period, 385 articles from three sources of information were analyzed: Press literature, scientific literature, and gray literature. Of these, the greatest amount of information corresponding to the context and the aggressor animal was found in the press literature, where it was recorded that the greatest number of records reported in the Chilean articles were caused by potentially dangerous breeds (87.50%), having significant differences with the gray literature (p = 0.030), and in Spain, the greatest number of attacks was also made by potentially dangerous dogs 91.30% (21/23), statistically significant differences with the gray literature (p = 0.002) and with the indexed (p < 0.001). In the case of the scientific and gray literature, the greatest amount of information was found about the victim of the attack and the treatments applied to them. In these cases, the highest percentage of victims included in the reports contained both sexes for the two literatures (44.62% and 87.71%, respectively). Regarding the treatment applied, in the scientific literature in most of the reports, the patients received washings, rabies vaccine, and tetanus vaccine (46.26%) and presented significant differences in Chile with the information contained in the gray literature (p = 0.023), in Spain with the gray (p = 0.017) and with the press (p = 0.023). In conclusion, the press literature differs in multiple variables with the information reported in the scientific literature and, in some cases, with the gray literature. The reason why the material that is being distributed to the population would not coincide in multiple relevant variables in other literature and the representative reality of the problem is the basis for this topic.

Hair of the Dog? Periprosthetic Joint Infection with Streptococcus can is

A 61-year-old man underwent elective primary total hip arthroplasty at an academic center and presented to the emergency department 2 weeks later with a periprosthetic infection. Intraoperative cultures were positive for Streptococcus canis. He was successfully treated with one-stage revision and 6 weeks of intravenous cefazolin. It was later determined that the patient has a pet dog who frequently licks his legs. We hypothesize that patients with pets are more likely to carry this pathogen as part of their skin microbiome, and further research is required to establish whether S. canis poses an infectious risk beyond that of normal group B Streptococcus skin flora and if preoperative decolonization strategies are warranted.

An Outbreak of Subclinical Mastitis in a Dairy Herd Caused by a Novel Streptococcus canis Sequence Type (ST55)

Simple Summary

Although Streptococcus (S). canis is mainly isolated from carnivores, intramammary infection in dairy cows caused by this bacterium have been reported. Cats and dogs with access to the barn have been considered as the main source of these infections. Here, we report subclinical mastitis and substantially increased bulk milk somatic cell counts in a dairy herd. During a herd visit, management and hygiene practices were evaluated and data from the milk quality control program were retrieved. Furthermore, quarter milk samples, mucosal swabs from farm cats and a dog, and swabs from the milking unit were aseptically collected. The samples were examined bacteriologically, and S. canis was identified using conventional phenotypic methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Genetic relationships between S. canis isolates were determined by multilocus sequence typing, revealing that all S. canis isolates shared the same sequence type, presenting a new combination of alleles for which a new number (ST55) was assigned. As the most likely source of intramammary infection, a farmyard cat was identified. The concurrent treatment of all positive cows and the improvement of management (no further access of carnivores to the barn) lead to positive results, including a decreased somatic cell count.

Abstract

The present case report provides data on the phenotypic and genotypic properties of S. canis isolated from nine dairy cows with subclinical mastitis (SCC greater than 200,000 cells/mL in the quarter milk sample, no clinical signs) and from a cat living in the barn and reports the eradication of the pathogen from the herd with an automatic milking system. The isolates were identified using conventional bacteriology, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and genetic relationships were investigated by multilocus sequence typing (MLST). Udder health management and hygiene instructions comprised the removal of the carnivores from the barn, strict monitoring of milking hygiene and techniques to avoid new infections via the milking robot, with simultaneous therapy for all infected cows. Phenotypic and genotypic properties of all isolates were identical. MLST revealed a unique sequence type (ST55) and a farmyard cat was identified as the most likely source of the S. canis infection in cows. The simultaneous treatment of all infected cows and management and hygiene improvements lead to a decreased SCC within four weeks.

Novel Models of Streptococcus canis Colonization and Disease Reveal Modest Contributions of M-Like (SCM) Protein

Streptococcus canis is a common colonizing bacterium of the urogenital tract of cats and dogs that can also cause invasive disease in these animal populations and in humans. Although the virulence mechanisms of S. canis are not well-characterized, an M-like protein, SCM, has recently identified been as a potential virulence factor. SCM is a surface-associated protein that binds to host plasminogen and IgGs suggesting its possible importance in host-pathogen interactions. In this study, we developed in vitro and ex vivo blood component models and murine models of S. canis vaginal colonization, systemic infection, and dermal infection to compare the virulence potential of the zoonotic S. canis vaginal isolate G361 and its isogenic SCM-deficient mutant (G361∆scm). We found that while S. canis establishes vaginal colonization and causes invasive disease in vivo, the contribution of the SCM protein to virulence phenotypes in these models is modest. We conclude that SCM is dispensable for invasive disease in murine models and for resistance to human blood components ex vivo, but may contribute to mucosal persistence, highlighting a potential contribution to the recently appreciated genetic diversity of SCM across strains and hosts.

Intracellular Invasion Ability and Associated Microbiological Characteristics of Streptococcus canis in Isolates from Japan

This study evaluated the cell invasion ability (CIA) of Streptococcus canis isolates, and clarified the relationship between high-frequency CIA and its microbiological features. Of the companion animal-origin isolates (n = 117) that were obtained in 2017, 40 isolates were randomly selected with the host information, with two human blood-origin isolates included. CIA was measured using human colon carcinoma epithelium and the hemolytic activity (HA) using sheep blood, along with S. canis M-like protein (SCM) allele typing, sequence type (ST) determination, and antimicrobial resistance (AMR) phenotyping/genotyping. CIA measurements revealed that 19 and 24 isolates had high- and low-frequencies, respectively. HA assessment revealed that 24 and 19 isolates were categorized as high- and low- level, respectively. No difference was observed in the high-/low-level HA between the high- /low-frequency CIA populations. A significant difference was found in the high-/low-frequency CIA between the SCM group I/II populations. Additionally, a significantly higher CIA was found in the SCM allele type 10/type 11 than in the others. A significant association was observed between high-frequency CIA and the ST21/ST41 populations. No difference was found in the high-/low-frequency CIA between the presence and absence of the AMR phenotype/genotype. These observations suggest a relationship between high-frequency CIA and its microbiological characteristics (SCM allele type 10/type 11 or ST21/ST41).

Draft Genome Sequence of Blood-Origin Streptococcus canis Strain FU149, Isolated from a Dog with Necrotizing Soft Tissue Infection

The draft genome sequence of the blood-origin Streptococcus canis strain FU149, isolated from a dog with a necrotizing soft tissue infection in Japan, is reported. The genome size was 2.108 Mbp, with a G+C content of 39.5%. Sequences unmapped to the reference genome sequence of NCTC 12191^T (GenBank accession number LR134293) were characterized.

Novel diverse sequences of the Streptococcus canis M-like protein (SCM) gene and their prevalence in diseased companion animals: Association of their alleles with sequence types

OBJECTIVE

We aimed to determine novel alleles and their prevalence in Streptococcus canis M-like protein (SCM) and to elucidate association of their alleles with sequence types (STs)/clonal complexes (CCs) and antimicrobial resistance (AMR) phenotypes/genotypes.

METHODS

We amplified and sequenced scm, by using primers reported by Pinho recently, for 40 isolates in 2015 and 2017, in which the sequences could not be determined with conventional primers. Isolates, for which SCM alleles, STs, and AMR phenotypes/genotypes were previously determined, were included as controls. A phylogenetic tree of SCM amino acid sequences was constructed. Alleles, based on the tree positions with their prevalence, as well as STs/CCs and AMR phenotypes/genotypes were characterized.

RESULTS

Although one isolate possessed SCM allele type 1, 39 isolates had novel allele types 10-15, based on cluster analysis. The 11 and 12 allele types were firstly found in this study. We designated novel allele types as group II and non-novel allele types as group I. Prevalence of group II alleles was 29.9% and 16.2% in 2015 and 2017. Prevalent group II types were allele 10 (10.3%), allele 11 (2.7%), and allele 15 (3.3%) through both periods. There was a significant difference in distribution of STs/CCs between groups I/II SCM populations. We found significant differences in distribution of macrolide/lincosamide AMR genotype (7.7% vs. 26.8%) and AMR rates of fluoroquinolone (0% vs. 12.5%) between the two populations.

CONCLUSION

Our study presents group II scm sequences and their prevalence among diseased companion animals in Japan, with association of their alleles with STs.

Novel Quinolone Nonsusceptible Streptococcus canis Strains with Point Mutations in Quinolone Resistance-Determining Regions and Their Related Factors

This study investigated quinolone nonsusceptible Streptococcus canis with point mutations in quinolone resistance-determining regions (QRDRs). After selecting targets from 185 isolates, we tested antimicrobial susceptibility using levofloxacin, ciprofloxacin, norfloxacin, and moxifloxacin. We also determined the amino acid sequences of QRDRs in gyrA/gyrB/parC/parE genes and their point mutations. Finally, we performed S. canis-derived M-like protein (SCM) allele typing, multilocus sequence typing, and antimicrobial resistance genotyping. Correlations between nonsusceptible strains and their related factors were examined. We found 13 (7.0%) nonsusceptible isolates consisting of two classes, high-level minimum inhibitory concentrations (MICs) (n = 7, 3.8%) and low-level MICs (n = 6, 3.2%). Mutations Ser81Phe/Ser81Tyr/Glu85Lys in gyrA, Ser67Phe/Ser67Tyr/Asp71Tyr in parC, Asp438Asn in parE, and Gly408Asp in gyrB were observed in these nonsusceptible strains. Common mutations included Ser81 and Ser67/Asp71; additionally, we found one strain each with Glu85, Asp438, and Gly408 mutations. There was a significant correlation between nonsusceptible isolates and the presence of SCM allele type 2, sequence type 46, tetracyclineresistance genes, and macrolide/lincosamide-resistance genes. These results could be used in future, by veterinarians while treating companion animals with clinical symptoms of streptococcal infections.

One Health and Streptococcus Canis in the Emergency Department: A Case of Cellulitis and Bacteremia in an Immunocompromised Patient Treated With Etanercept

BACKGROUND

One Health is a biomedical approach that aims to optimize the health of humans, animals, and the environment through interdisciplinary collaboration. Cellulitis is an infection of the dermis and subcutaneous fat that may be caused by zoonotic streptococci species.

CASE REPORT

We report a case of cellulitis caused by Streptococcus canis in a woman who was taking Etanercept. We frame the presentation within a One Health approach and urge emergency physicians to collaborate with veterinarians in the management of patients with zoonotic diseases who are discharged home. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pets are a source for zoonotic diseases, including resistant bacteria, that pose particular risk to immunocompromised patients. Emergency physicians often discharge patients with potential zoonotic infections such as cellulitis home without a long-term, holistic care plan, according to a One Health approach. Physicians should then collaborate with veterinarians in caring for humans and animals.

Streptococcus canis multilocus sequence typing in a case series of dogs with ulcerative keratitis

OBJECTIVE

To determine whether four isolates of Streptococcus canis (S canis) recovered from dogs diagnosed with ulcerative keratitis at the Animal Health Trust (AHT) were genetically related to other ocular isolates that are registered in the online database.

ANIMAL STUDIED

Four S canis corneal isolates.

PROCEDURES

Clinical and laboratory records between 2016 and 2017 were searched for dogs with ulcerative keratitis for which microbiology analysis was consistent with the growth of S canis. Genomic DNA was extracted for sequencing (Illumina MiSeq), and multilocus sequence types (STs) were determined using MLST 1.8 relative to the 44 sequence types of S canis available. A neighbor-joining tree was constructed in MEGA v4.0. A two-sided Fisher's exact test was used to determine any associations between the isolated strains and ocular infections of dogs.

RESULTS

Four strains were isolated from pugs (cases 1-4) with ulcerative keratitis. Genome sequencing identified ST-27 (case 1), ST-9 (case 3), and ST-13 (cases 2 and 4). STs 13 and 27 are members of Clonal Complex (CC)-13. Analysis of the multilocus sequence typing database revealed that CC-13 strains accounted for six of the twelve isolates recovered from the eye exudates of dogs (P = .0078).

CONCLUSIONS

There is early evidence that the CC-13 group of S canis is associated with ocular infections in dogs. We provide draft genome sequences toward the future identification of virulence mechanisms associated with streptococcal keratitis in dogs.

Draft Genome Sequence of Streptococcus canis Clinical Strain OT1, Isolated from a Dog Owner with Invasive Infection without a Dog Bite in Japan

Streptococcus canis is a β-hemolytic bacterium that can cause invasive infections in animals and humans. Here, we report a draft genome sequence of S. canis strain OT1, isolated from a female dog owner with bacteremia without a dog bite. The draft genome comprises 2,030,366 bp in 48 contigs.

Streptococcus canis is a β-hemolytic bacterium that can cause invasive infections in animals and humans. Here, we report a draft genome sequence of S. canis strain OT1, isolated from a female dog owner with bacteremia without a dog bite. The draft genome comprises 2,030,366 bp in 48 contigs.

Homophilic protein interactions facilitate bacterial aggregation and IgG-dependent complex formation by the Streptococcus canis M protein SCM

Streptococcus canis is a zoonotic agent that causes serious invasive diseases in domestic animals and humans, but knowledge about its pathogenic potential and underlying virulence mechanisms is limited. Here, we report on the ability of certain S. canis isolates to form large bacterial aggregates when grown in liquid broth. Bacterial aggregation was attributed to the presence and the self-binding activity of SCM, the M protein of S. canis, as evaluated by bacterial sedimentation assays, immunofluorescence- and electron microscopic approaches. Using a variety of truncated recombinant SCM fragments, we demonstrated that homophilic SCM interactions occur via the N-terminal, but not the C-terminal part, of the mature M protein. Interestingly, when incubated in human plasma, SCM forms soluble protein complexes comprising its known ligands, immunoglobulin G (IgG) and plasminogen (Plg). Co-incubation studies with purified host proteins revealed that SCM-mediated complex formation is based on the interaction of SCM with itself and with IgG, but not with Plg or fibrinogen (Fbg), well-established constituents of M protein-mediated protein complexes in human-associated streptococci. Notably, these soluble, SCM-mediated plasma complexes harbored complement factor C1q, which can induce complement breakdown in the periphery and therefore represent another immune evasion mechanism of SCM.

Streptococcus canis Are a Single Population Infecting Multiple Animal Hosts Despite the Diversity of the Universally Present M-Like Protein SCM

Streptococcus canis is an animal pathogen which occasionally causes infections in humans. The S. canis M-like protein (SCM) encoded by the scm gene, is its best characterized virulence factor but previous studies suggested it could be absent in a substantial fraction of isolates. We studied the distribution and variability of the scm gene in 188 S. canis isolates recovered from companion animals (n = 152), wild animal species (n = 20), and humans (n = 14). Multilocus sequence typing, including the first characterization of wildlife isolates, showed that the same lineages are present in all animal hosts, raising the possibility of extensive circulation between species. Whole-genome analysis revealed that emm-like genes found previously in S. canis correspond to divergent scm genes, indicating that what was previously believed to correspond to two genes is in fact the same scm locus. We designed primers allowing for the first time the successful amplification of the scm gene in all isolates. Analysis of the scm sequences identified 12 distinct types, which could be divided into two clusters: group I (76%, n = 142) and group II (24%, n = 46) sharing little sequence similarity. The predicted group I SCM showed extensive similarity with each other outside of the N-terminal hypervariable region and a conserved IgG binding domain. This domain was absent from group II SCM variants found in isolates previously thought to lack the scm gene, which also showed greater amino acid variability. Further studies are necessary to elucidate the possible host interacting partners of the group II SCM variants and their role in virulence.

Analysis of the Type II-A CRISPR-Cas System in Streptococcus canis Isolated from Diseased Companion Animals and One Human Patient in Japan

We determined the whole-genome sequence (WGS) of Streptococcus canis strain TA4 harboring the M-like protein gene (scm); the strain was isolated from a human patient presenting with bacteremia. The potential of type II-A clustered regularly interspaced short palindromic repeats (CRISPR) array-based typing was evaluated, and the genetic relation was elucidated between spacer genogroups and scm prevalence and/or polymorphisms among the isolates from 19 diseased companion animals and the human patient. CRISPRFinder and CRISPRCasFinder detected the type II-A locus with the same repeat sequences in strain TA4 and another WGS of S. canis strain, isolated from a cow with mastitis. An optimized PCR-based amplification method was used to sequence the region covering the locus around the leader and terminal repeat sequences. Among the 20 isolates sequenced, 16 strains (including TA4) were identified with the CRISPR array. We conducted comparative analysis of the homologous spacer sequences and performed grouping based on the successive common ancestral spacer types. These 16 isolates were assigned to five genogroups (A to E) with scm being absent in genogroup A. We found a relationship between genogroups C and E and allele type 1 of the deduced M-like protein. These preliminary findings suggest the feasibility of CRISPR array-based typing and a genetic relation between the spacer genogroups and scm prevalence and/or polymorphisms in the isolates.

Species Identification of β-Hemolytic Streptococci from Diseased Companion Animals and Their Antimicrobial Resistance Data in Japan (2017)

This study aimed to identify the species and assess the antimicrobial resistance (AMR) of β-hemolytic streptococci isolated from companion animals in Japan. Strains were isolated from clinical specimens of 131 companion animals that exhibited symptoms in April-May 2017. We identified strains by 16S rRNA sequencing and assessed their antimicrobial susceptibility using the broth microdilution method. AMR genes erm(A)-erm(B)-mef(A) and tet(M)-tet(O)-tet(K)-tet(L)-tet(S) in all isolates were amplified by PCR. 16S rRNA sequencing identified β-hemolytic streptococcal species as Streptococcus canis (n = 117, 89.3%), S. agalactiae (n = 7), S. dysgalactiae subsp. equisimilis (n = 5), S. dysgalactiae subsp. dysgalactiae (n = 1), and S. equi subsp. zooepidemicus (n = 1). Overall AMR rates were 39.7% for minocycline, 19.8% for erythromycin, and 17.6% for clindamycin, with a minimum inhibitory concentration (MIC₉₀) of > 4, > 2, and > 1 μg/mL, respectively. AMR genotyping showed the presence of single or mixed types: erm(B)-mef(A) and tet(M)-tet(O)-tet(L)-tet(S). There was a significant relationship between tetracycline-resistance genotypes and open pus/skin-derived specimens. These observations identify some unique features of β-hemolytic streptococcal isolates from companion animals in Japan, such as the dominant isolation of S. canis and resistance to tetracycline, macrolide, and lincosamide antibiotics, in terms of species identification and AMR properties.

Draft Genome Sequence of Streptococcus canis Clinical Strain TA4, Harboring the M-Like Protein Gene and Isolated in Japan from a Patient with Bacteremia

Streptococcus canis is an animal-origin β-hemolytic bacterium that can cause severe infections in animals and occasionally infects humans. Here, we report a draft genome sequence of an S. canis strain harboring the M-like protein gene. This strain was isolated from a patient with bacteremia (reported by Taniyama et al. [D. Taniyama, Y. Abe, T. Sakai, T. Kikuchi, and T. Takahashi, IDCases 7:48–52, 2017, https://doi.org/10.1016/j.idcr.2017.01.002]). The draft genome comprises 2,129,080 bp in 60 contigs.