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Genomics May 2022Helcococcus kunzii is a commensal Gram-positive bacterial species recovered from the human skin microbiota and considered as an opportunistic pathogen. Although little...
Helcococcus kunzii is a commensal Gram-positive bacterial species recovered from the human skin microbiota and considered as an opportunistic pathogen. Although little is known about its clinical significance, its increased abundance has been reported in infected wounds, particularly in foot ulcers in persons with diabetes. This species is usually detected in mixed cultures from human specimens and frequently isolated with Staphylococcus aureus. Modulation of staphylococci virulence by H. kunzii has been shown in an infection model of Caenorhabditis elegans. The aim of this study was to compare the genomes of two H. kunzii strains isolated from foot ulcers -isolate H13 and H10 showing high or low impact on S. aureus virulence, respectively- and the H. kunzii ATCC51366 strain. Whole genome analyses revealed some differences between the two strains: length (2.06 Mb (H13) and 2.05 Mb (H10) bp), GC content (29.3% (H13) and 29.5% (H10)) and gene content (1,884 (H13) and 1,786 (H10) predicted genes). The core-proteome phylogenies within the genus characterised H. kunzii H13 and H10 as genetically similar to their ancestor. The main differences between the strains were mainly in sugar-associated transporters and various hypothetical proteins. Five targets were identified as potentially involved in S. aureus virulence modulation in both genomes: the two-component iron export system and three autoinducer-like proteins. Moreover, H13 strain harbours a prophage inserted in 1,261,110-1,295,549 (attL-attR), which is absent in H10 strain. The prophage PhiCD38_2 was previously reported for its ability to modulate secretion profile, reinforcing the autoinducer-like hypothesis. In the future, transcriptomics or metaproteomics approaches could be performed to better characterize the H13 strain and possibly identify the underlying mechanism for S. aureus virulence modulation.
Topics: Humans; Diabetic Foot; Staphylococcus aureus; Staphylococcal Infections; Genomics; Diabetes Mellitus
PubMed: 35413435
DOI: 10.1016/j.ygeno.2022.110365 -
BMC Infectious Diseases Jun 2015Helcococcus kunzii is a facultative anaerobic bacterium that was first described by Collins et al. in 1993, and was initially considered as a commensal of the human... (Review)
Review
BACKGROUND
Helcococcus kunzii is a facultative anaerobic bacterium that was first described by Collins et al. in 1993, and was initially considered as a commensal of the human skin, in particular of lower extremities. Human infections caused by H. kunzii remain rare with only a few cases published in the pubmed database. Nevertheless recent reports indicate that this microorganism has to be considered as an opportunistic pathogen that can be involved in severe infections in human. To the best of our knowledge, we describe here the first known case of infectious endocarditis caused by H. kunzii.
CASE PRESENTATION
A 79 year-old man reporting severe polyvascular medical history attended the emergency ward for rapid deterioration of his general state of health. After physical examination and paraclinical investigations, the diagnosis of infectious endocarditis on native mitral valve caused by Helcococcus kunzii was established based on Dukes criteria. MALDI-TOF mass spectrometry and 16S rDNA sequencing allowed an accurate identification to the species level of Helcococcus kunzii. The patient was successfully treated by a medico-surgical approach. The treatment consisted in intravenous amoxicillin during four weeks and mitral valve replacement with a bioprosthestic valve. After an in depth review of patient's medical file, the origin of infection remained unknown. However, a cutaneous portal of entry cannot be excluded as the patient and his General Practitioner reported chronic ulcerations of both feet.
CONCLUSIONS
We describe here the first case of endocarditis caused by H. kunzii in an elderly patient with polyvascular disease. This report along with previous data found in the literature emphasizes the invasive potential of this bacterial species as an opportunistic pathogen, in particular for patient with polyvascular diseases. MALDI-TOF mass spectrometry and 16S rDNA sequencing are reliable tools for H. kunzii identification. We also sequenced in this work H.kunzii type strain 103932T CIP and deposited in the Genbank under accession number KM403387. We noticed a 14 base difference between our sequence and the original sequence deposited by Collins et al. under Genbank accession number X69837. Hopefully, the spread of next generation sequencing tools would lead to a more accurate classification of clinical strains.
Topics: Aged; Aortic Aneurysm, Abdominal; Carotid Artery Diseases; DNA, Ribosomal; Endocarditis, Bacterial; Foot Ulcer; Gram-Positive Bacterial Infections; High-Throughput Nucleotide Sequencing; Humans; Male; Mitral Valve; Myocardial Ischemia; Peptostreptococcus; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 26099275
DOI: 10.1186/s12879-015-0984-y -
Journal of Clinical Microbiology Mar 2014Helcococcus spp. are Gram-positive, catalase-negative, facultatively anaerobic cocci that are associated with wound and prosthetic joint infections as well bacteremia...
Helcococcus spp. are Gram-positive, catalase-negative, facultatively anaerobic cocci that are associated with wound and prosthetic joint infections as well bacteremia and empyema. Five Helcococcus spp. strains were isolated from our patient population, including 2 strains of Helcococcus kunzii from trauma-associated wounds, 2 Helcococcus sueciensis strains from blood and abscess, and a novel Helcococcus spp. strain from blood associated with urosepsis. Based on the phenotypic and phylogenetic evidence, we propose that the unknown bacterium be classified as Helcococcus seattlensis sp. nov. We found that all 5 tested Helcococcus strains grew as satellite colonies around Staphylococcus aureus and, interestingly, both H. kunzii strains were isolated together with S. aureus. In addition to 16S rRNA gene sequencing, conventional methods for leucine aminopeptidase (LAP) and pyrrolidonyl arylamidase (PYR) testing can be cost-effective and efficient for differentiation of Helcococcus spp. from Abiotrophia and Granulicatella species. Using nonstandard methods, we found that all tested Helcococcus spp. had high MICs of >4/76 μg/ml for trimethoprim-sulfamethoxazole, an antibiotic commonly used to treat urinary tract infections. High MICs for erythromycin, azithromycin, and clindamycin, and intermediate to high MICs for moxifloxacin, levofloxacin, and gentamicin were also observed among the Helcococcus strains.
Topics: Anti-Bacterial Agents; Bacterial Typing Techniques; Blood; DNA, Bacterial; DNA, Ribosomal; Gram-Positive Bacteria; Gram-Positive Bacterial Infections; Humans; Microbial Sensitivity Tests; Molecular Sequence Data; RNA, Ribosomal, 16S; Sepsis; Sequence Analysis, DNA; Urinary Tract Infections
PubMed: 24371247
DOI: 10.1128/JCM.03076-13 -
Journal of Clinical Microbiology Aug 2015From 2008 to 2013, 39 Helcococcus kunzii strains were collected from human clinical specimens (79% from foot ulcers), and 85% of the 39 patients were infected....
From 2008 to 2013, 39 Helcococcus kunzii strains were collected from human clinical specimens (79% from foot ulcers), and 85% of the 39 patients were infected. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and molecular methods accurately identified all isolates. This large study of clinical observations confirms the potential pathogenic role of H. kunzii.
Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteriological Techniques; Female; Firmicutes; Gram-Positive Bacterial Infections; Humans; Male; Middle Aged; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Young Adult
PubMed: 25994161
DOI: 10.1128/JCM.00947-15 -
Frontiers in Cellular and Infection... 2017Social bacterial interactions are considered essential in numerous infectious diseases, particularly in wounds. Foot ulcers are a common complication in diabetic...
Social bacterial interactions are considered essential in numerous infectious diseases, particularly in wounds. Foot ulcers are a common complication in diabetic patients and these ulcers become frequently infected. This infection is usually polymicrobial promoting cell-to-cell communications. is the most prevalent pathogen isolated. Its association with , commensal Gram-positive cocci, is frequently described. The aim of this study was to assess the impact of co-infection on virulence of both and strains in a model. To study the host response, qRT-PCRs targeting host defense genes were performed. We observed that strains harbored a very low (LT50: 5.7 days ± 0.4) or an absence of virulence (LT50: 6.9 days ± 0.5). In contrast, strains (LT50: 2.9 days ± 0.4) were significantly more virulent than all ( < 0.001). When and strains were associated, significantly reduced the virulence of the strain in nematodes (LT50 between 4.4 and 5.2 days; < 0.001). To evaluate the impact of these strains on host response, transcriptomic analysis showed that the ingestion of led to a strong induction of defense genes (, and ) while did not. No statistical difference of host response genes expression was observed when were infected with either alone or with + . Moreover, two well-characterized virulence factors ( and ) present in were down-regulated when were co-infected with . This study showed that decreased the virulence of without modifying directly the host defense response. Factor(s) produced by this bacterium modulating the staphylococci virulence must be investigated.
Topics: Animals; Caenorhabditis elegans; Coinfection; Disease Models, Animal; Firmicutes; Gene Expression Profiling; Gram-Positive Bacterial Infections; Microbial Interactions; Real-Time Polymerase Chain Reaction; Survival Analysis; Virulence
PubMed: 28361041
DOI: 10.3389/fcimb.2017.00077 -
The Journal of Antimicrobial... Feb 2020To determine the mechanism of induction of erm(47) and its atypical expression in the Gram-positive opportunistic pathogen Helcococcus kunzii, where it confers...
OBJECTIVES
To determine the mechanism of induction of erm(47) and its atypical expression in the Gram-positive opportunistic pathogen Helcococcus kunzii, where it confers resistance to a subset of clinically important macrolide, lincosamide and streptogramin B (MLSB) antibiotics.
METHODS
The resistant H. kunzii clinical isolate UCN99 was challenged with subinhibitory concentrations of a wide range of ribosome-targeting drugs. The methylation status of the H. kunzii ribosomal RNA at the MLSB binding site was then determined using an MS approach and was correlated with any increase in resistance to the drugs.
RESULTS
The H. kunzii erm(47) gene encodes a monomethyltransferase. Expression is induced by subinhibitory concentrations of the macrolide erythromycin, as is common for many erm genes, and surprisingly also by 16-membered macrolide, lincosamide, streptogramin, ketolide, chloramphenicol and linezolid antibiotics, all of which target the 50S ribosomal subunit. No induction was detected with spectinomycin, which targets the 30S subunit.
CONCLUSIONS
The structure of the erm(47) leader sequence functions as a hair trigger for the induction mechanism that expresses resistance. Consequently, translation of the erm(47) mRNA is tripped by MLSB compounds and also by drugs that target the 50S ribosomal subunit outside the MLSB site. Expression of erm(47) thus extends previous assumptions about how erm genes can be induced.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Firmicutes; Lincosamides; Macrolides; Methyltransferases; Ribosomes; Streptogramin B
PubMed: 31670815
DOI: 10.1093/jac/dkz441 -
BMC Infectious Diseases Jul 2021Infection of Helcococcus kunzii(H. kunzii) from diabetic foot wound is rarely reported. This case report describes the infection of H.kunzii and highlights the...
BACKGROUND
Infection of Helcococcus kunzii(H. kunzii) from diabetic foot wound is rarely reported. This case report describes the infection of H.kunzii and highlights the therapeutic effect on H.kunzii from a diabetic foot wound.
CASE PRESENTATION
In this study, one H. kunzii strain was isolated from a patient with diabetic foot, which was confirmed by 16S rRNA gene analysis and MALDI-TOF-MS. It is the first Chinese case of H. kunzii in a patient with diabetic foot. As a result of the lack of antibiotic sensitivity data and multiple comorbidities, antibiotics were used cautiously, and those administered during the first 3 months were ineffective. Then, vacuum sealing drainage (VSD) was applied during hospitalization; no antibiotics were used and the wound healed well.
CONCLUSIONS
VSD alone may be more effective in treating diabetic feet infected with H. kunzii, which may provide reference for clinical treatment of H. kunzii infection from diabetic foot.
Topics: Aged; China; Diabetic Foot; Firmicutes; Gram-Positive Bacterial Infections; Humans; Male; RNA, Ribosomal, 16S
PubMed: 34284730
DOI: 10.1186/s12879-021-06309-y -
The Journal of General and Applied... 2013
Topics: Animals; Cattle; Cattle Diseases; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Endometritis; Female; Gram-Positive Bacteria; Molecular Sequence Data; Phylogeny; Puerperal Infection; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 24201149
DOI: 10.2323/jgam.59.371 -
International Wound Journal Aug 2015We report the case of an 86-year-old man with severe wound infection originating from a chronic crural ulcer of the lower limb, which under negative pressure wound...
We report the case of an 86-year-old man with severe wound infection originating from a chronic crural ulcer of the lower limb, which under negative pressure wound therapy led to excessive tissue necrosis and perforation of the anterior tibial artery. A swab taken 10 and 7 days preoperatively was positive for Helcococcus kunzii. H. kunzii has been described as a potentially pathogenic organism. The questions whether the negative pressure wound therapy itself caused the bleeding or the negative pressure wound therapy, which generates an anaerobic atmosphere, has triggered the growth and invasion of the facultative anaerobic bacterium H. kunzii and owing to the infection the artery perforated or whether the bacteria has no influence at all remain currently unanswered. After surgical debridement the signs of infection were completely eliminated, and a free musculocutaneous flap led to rapid healing of the wound. Following which H. kunzii was no longer detectable.
Topics: Aged, 80 and over; Chronic Disease; Free Tissue Flaps; Gram-Positive Bacterial Infections; Humans; Leg Ulcer; Male; Necrosis; Negative-Pressure Wound Therapy; Osteomyelitis; Tibia; Wound Infection; Wounds and Injuries
PubMed: 23855685
DOI: 10.1111/iwj.12133 -
BMJ Case Reports May 2017An 88-year-old man with history of bioprosthetic aortic valve replacement was hospitalised with fever, chills, malaise and right lower extremity cellulitis. Laboratory...
An 88-year-old man with history of bioprosthetic aortic valve replacement was hospitalised with fever, chills, malaise and right lower extremity cellulitis. Laboratory investigations revealed leucocytosis and blood cultures grew Although transoesophageal echocardiography was negative for endocarditis, the patient was treated with 4 week of intravenous ceftriaxone. However, he was readmitted 6 weeks later with symptoms of fever, chills and hypoxia in setting of recurrent bacteraemia. A repeat transoesophageal echocardiogram revealed a mobile mass on bioprosthetic aortic valve, severe perivalvular insufficiency with pseudoaneurysm formation, and severe native mitral and tricuspid valve regurgitation. Cardiothoracic surgery was consulted and the patient underwent replacement of aortic valve and aortic root, and tricuspid and mitral valve repairs. Histological examination of excised bioprosthetic aortic valve revealed active endocarditis with cocci identified on silver stain. Patient was successfully treated with 4-week course of intravenous ceftriaxone and was doing well at 2-year follow-up.
Topics: Aged, 80 and over; Anti-Bacterial Agents; Aortic Valve; Ceftriaxone; Cellulitis; Diagnosis, Differential; Echocardiography, Transesophageal; Endocarditis, Bacterial; Firmicutes; Gram-Positive Bacterial Infections; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Humans; Lower Extremity; Male; Prosthesis-Related Infections
PubMed: 28473362
DOI: 10.1136/bcr-2017-219330