Diabetic Foot UlcerPETTENK-OSNCT06688084
Pathogenicity Factors of Staphylococcus Pettenkoferi in Foot Wounds and Osteitis in Diabetic Patients
An observational study of Diabetic Foot Ulcer, run by Centre Hospitalier Universitaire de Nīmes at 1 site in France.
Trial summary
Gram-positive cocci, particularly Staphylococcus aureus and coagulase-negative staphylococci (SCoN), are the bacteria most frequently isolated from diabetic foot ulcers. Although studies have been carried out on the role of S. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Diabetic Foot Ulcer
- What is being tested?
- Molecular epidemiology of the collection, Study of the resistome of the S. pettenkoferi population and Study of the virulome of the S. pettenkoferi population
- How many people
- 230 participants
- Where
- 1 siteFrance
- Study dates
- 1 Jan 2024to 31 Dec 2025
- How long will I take part?
- 2 Years
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: The collection of strains at the Nîmes University Hospital site from 9 European laboratories collected between 2015 and 2023 for a total of 108 months was carried out between November 2021 and August 2023.
Who may be able to join
- Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi
Who cannot join
- Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluation of Pathogenicity Factors of Staphylococcus Pettenkoferi in Foot Wounds and Osteitis in Diabetic Patients
Gram-positive cocci, particularly Staphylococcus aureus and coagulase-negative staphylococci (SCoN), are the bacteria most frequently isolated from diabetic foot ulcers. Although studies have been carried out on the role of S. aureus in the unfavorable evolution of these wounds, no studies have focused on the role of SCoN. Of the fifty or so SCoN species, not all have the same virulence potential. The role of Staphylococcus pettenkoferi is unknown, yet this bacterium is the 7th most frequently identified in diabetic foot ulcers, suggesting that it may also be involved in the pathophysiology of these infections. At Nîmes University Hospital, this bacterium is mainly identified in samples from diabetic foot ulcers or osteitis in our laboratory and 80% of the bacteria present are in biofilms.It is essential to understand the mechanisms governing these bacterial interactions and establish the true pathogenic potential of these bacteria. Recently, the Nîmes team showed that a strain of S. pettenkoferi (SP165) isolated from foot osteitis in a diabetic patient had real virulence potential. SP165 could not only produce biofilm, but could also survive in human blood, human keratinocytes and murine and human macrophages. It also caused significant embryonic mortality in a zebrafish model. A second study of 29 isolates from Nîmes University Hospital subsequently demonstrated that there were two predominant clones with different virulences. Three biofilm production profiles (rapidly and highly biofilm-producing, slowly biofilm-producing and non-biofilm-producing) and two zebrafish profiles (highly and moderately lethal) were reported by phenotypic and genomic analyses on this panel of strains. Genes for resistance, virulence and biofilm production were also found on their genomes.
Read the detailed description
Gram-positive cocci, in particular Staphylococcus aureus and coagulase-negative staphylococci (SCoN), are the bacteria most frequently isolated from diabetic foot ulcers. While studies have been carried out on the role of S. aureus in the unfavorable evolution of these wounds, no study has focused on the role of SCoN. Of the fifty or so SCoN species, not all have the same virulence potential. The role of Staphylococcus pettenkoferi is not known. Yet this bacterium is the 7th most frequently identified in diabetic foot ulcers, suggesting that it may also be involved in the pathophysiology of these infections. In the work of Loetsche et al. a study of the microbiome of 349 diabetic foot ulcer samples by targeted 16S rDNA sequencing showed that the genus Staphylococcus was the most abundant, with a relative abundance of 22.8%, including 13.3% S. aureus and 5.3% S. pettenkoferi.
At Nîmes University Hospital, this bacterium is mainly identified in samples from diabetic foot ulcers or osteitis in our laboratory (89 isolations of S. pettenkoferi from diabetic foot ulcer samples out of 167 isolations made of this bacterium between 2018 and 2022).The difficulty of managing chronic wounds also lies in the fact that almost 80% of the bacteria present are in biofilms. It has also been established that the environment in which bacteria are found, and in particular the interactions they establish between themselves, play a significant role in delayed wound healing. It is therefore essential to understand the mechanisms governing these bacterial interactions and to establish the true pathogenic potential of these bacteria.
Recently, our team demonstrated that a strain of S. pettenkoferi (SP165) isolated from foot osteitis in a diabetic patient had real virulence potential. As well as being able to produce biofilm, SP165 was able to survive in human blood, human keratinocytes and murine and human macrophages. It also demonstrated its virulence by causing significant embryonic mortality in the zebrafish model.
A second study of 29 isolates from Nîmes University Hospital subsequently demonstrated the existence of two predominant clones with different virulences.
Three biofilm production profiles (rapidly and highly biofilm-producing, slowly biofilm-producing and non-biofilm-producing) and two zebrafish virulence profiles (highly and moderately lethal) were reported by phenotypic and genomic analyses on this panel of strains. Genes for resistance, virulence and biofilm production were also found on their genomes.
- Conditions
- Diabetic Foot Ulcer
- Being tested
- Molecular epidemiology of the collection, Study of the resistome of the S. pettenkoferi population, Study of the virulome of the S. pettenkoferi population, Study of the resistance profiles of all S. pettenkoferi isolates, Selection of strains for in-depth phenotypic study
- Keywords
- Diabetes, Foot, Infection, Staphylococcus pettenkoferi, Osteitis
- Medical subject headings
- Diabetic Foot, Diabetes Mellitus, Infections, Osteitis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Molecular epidemiology of the collectionOther
Next-generation genomic sequencing (MICRO\&BIO platform, MiSeq, Illumina) and bioinformatics analyses. After validating data quality, genomes will be re-assembled using Spades software (version 3.15.4) and CLC® (Qiagen), then compared with the National Center for Biotechnology Information GenBank database. They will also be analysed on the online Type-Strain Genomes Server platform to accurately identify the bacteria. Genome annotation will be done using the DDBJ Fast Annotation and Submission Tool. Single nucleotide polymorphisms (SNP) analysis based on the alignment of whole genomes and core-genomes will be carried out using version 7 of MAFFT (multiple alignment using fast Fourier transform) software, then quantified using snp-dists (version 0.6.3). This approach will enable the molecular epidemiology of the collection of strains in France and other European countries to be clarified, and the main circulating clades to be assessed, particularly depending on the origin of samples.
Study of the resistome of the S. pettenkoferi populationOther
The resistome will be assessed by identifying known and described resistance genes in staphylococci using bioinformatics analyses of sequenced complete bacterial genomes. A search for plasmids will also be made using various specific software packages (ResFinder, CARD, PointFinder, Plasmidfinder, in-house pipeline).
Study of the virulome of the S. pettenkoferi populationOther
The virulome of the strains will be studied based on the genomic sequencing data obtained and with reference to the literature on Staphylococci. Various specific software packages (Pathogenfinder, Virulencefinder, in-house pipeline) will be used for this purpose.
Study of the resistance profiles of all S. pettenkoferi isolatesOther
Antibiotic resistance will be assessed using a Sensititer® plate (Thermo ScientificTM, Illkirch) to evaluate the minimum inhibitory concentration of isolates against a series of antibiotics commonly used for S. pettenkoferi infections, including new molecules currently on the market or in development, such as Ceftaroline, Ceftobiprole, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Minimum inhibitory concentration values will be interpreted in accordance with the recommendations of the Antibiogram Committee of the Société Française de Microbiologie (https://www.sfm-microbiologie.org/2021/04/23/casfm-avril-2021-v1-0/).
Selection of strains for in-depth phenotypic studyOther
Different strains of S. pettenkoferi isolated from foot osteitis in diabetic patients and non-diabetic osteitis will be selected according to the clades identified and phenotypically characterised by further analysis:
- Observation of culture characteristics (culture requirements, growth time, colony size and haemolytic capacity), (n=20)
- Determination of growth curves by measuring absorbance at 600 nm using the Infinite M Mano automatic absorbance reader (TECAN, Lyon), (n=20)
- Study of the ability to form biofilm in the presence (antibiofilmogram) (n=85) or absence (BioFilm Ring® test, Biofilm Control, St Beauzire) (n=85) of various antibiotics commonly used for the treatment of S. pettenkoferi infection during osteitis.
Selection of strains (n=3) for the virulence studyOther
Three strains of S. pettenkoferi isolated from foot osteitis in diabetic patients will be selected on the basis of the clades identified and the study of the virulome in order to be analysed on :
- In vitro cell culture models of macrophages (RAW 264.7) and osteoblasts (MC3T3-E1) to assess the invasion potential of these isolates by measuring internalisation rates (TECAN, Lyon) and LDH release (CyQUANT LDH Cytotoxicity kit), a sign of cellular toxicity of the isolate.
- An in vivo wound model on diabetic zebrafish (Dario rerio) with evaluation of their survival at 48h in the presence of the isolates by immersion.
These models were developed at the MICRO\&BIO Platform and the INSERM 1047 VBIC unit.
What is being measured
The primary outcome is the main question the study is designed to answer.
Genetic diversity of Staphyloccocus pettenkoferi strains isolated from osteitis and non-diabetic wounds, blood cultures and nasal carriage.
Number of clades estimated via typing by complete sequencing of the bacterial genomes of all S. pettenkoferi strains and analysis of phylogenetic distances (whole genome and core genome single nucleotide polymorphisms).
Measured: Day 0 to 3 months
Secondary outcomes (45)
Genetic diversity of Staphyloccocus pettenkoferi strains isolated from osteitis and non-diabetic wounds, blood cultures and nasal carriage.
Number of clades estimated via typing by complete sequencing of the bacterial genomes of all Staphylococcus pettenkoferi strains and analysis of phylogenetic distances.
Measured: 3 - 6 months
Resistome in the strain population according to sample origin:osteitis
The presence of antibiotic resistance genes (resistome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Resistome in the strain population according to sample origin: non-diabetic wounds
The presence of antibiotic resistance genes (resistome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Resistome in the strain population according to sample origin: diabetic wounds
The presence of antibiotic resistance genes (resistome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Resistome in the strain population according to sample origin: blood cultures
The presence of antibiotic resistance genes (resistome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Resistome in the strain population according to sample origin: nasal carriage
The presence of antibiotic resistance genes (resistome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Virulome in the strain population according to sample origin: osteitis
The presence of virulence genes (virulome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Virulome in the strain population according to sample origin: non-diabetic wounds
The presence of virulence genes (virulome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Virulome in the strain population according to sample origin: diabetic wounds
The presence of virulence genes (virulome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Virulome in the strain population according to sample origin: blood cultures
The presence of virulence genes (virulome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Virulome in the strain population according to sample origin: nasal carriage
The presence of virulence genes (virulome) will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Plasmids inthe strain population and according to sample origin: osteitis
The presence of plasmids will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Plasmids inthe strain population and according to sample origin: non-diabetic wounds
The presence of plasmids will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Plasmids inthe strain population and according to sample origin: diabetic wounds
The presence of plasmids will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Plasmids inthe strain population and according to sample origin: blood cultures
The presence of plasmids will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Plasmids inthe strain population and according to sample origin: nasal carriage
The presence of plasmids will be identified by bioinformatics analysis of sequenced bacterial genomes.
Measured: 3 - 6 months
Phenotypic resistance profiles in the population in a subsample of 85 strains
The minimum inhibitory concentration for a series of antibiotics will be recorded (antibiograms of isolates).These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: osteitis
Minimum inhibitory concentration for a series of antibiotics (antibiograms of isolates). These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: non-diabetic wounds
Minimum inhibitory concentration for a series of antibiotics (antibiograms of isolates). These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: diabetic wounds
Minimum inhibitory concentration for a series of antibiotics (antibiograms of isolates). These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: blood cultures
Minimum inhibitory concentration for a series of antibiotics (antibiograms of isolates). These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: nasal carriage
Minimum inhibitory concentration for a series of antibiotics (antibiograms of isolates). These antibiograms will be established on newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin.
Measured: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: osteitis
Biofilm formation index in the presence/absence of a series of antibiotics (antibiograms of isolates). These antibiotics will be newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Results recorded on a scale ranging from 0 = biofilm and 12 = no biofilm
Measured: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: non-diabetic wounds
Biofilm formation index in the presence/absence of a series of antibiotics (antibiograms of isolates). These antibiotics will be newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Results recorded on a scale ranging from 0 = biofilm and 12 = no biofilm
Measured: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: diabetic wounds
Biofilm formation index in the presence/absence of a series of antibiotics (antibiograms of isolates). These antibiotics will be newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Results recorded on a scale ranging from 0 = biofilm and 12 = no biofilm
Measured: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: blood cultures
Biofilm formation index in the presence/absence of a series of antibiotics (antibiograms of isolates). These antibiotics will be newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Results recorded on a scale ranging from 0 = biofilm and 12 = no biofilm
Measured: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: nasal carriage
Biofilm formation index in the presence/absence of a series of antibiotics (antibiograms of isolates). These antibiotics will be newly-marketed or current molecules such as Ceftarolin, Ceftobiprol, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Results recorded on a scale ranging from 0 = biofilm and 12 = no biofilm
Measured: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: osteitis
Bacterial growth curve by measuring absorbance on bacterial culture over time.
Measured: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: non-diabetic wounds
Bacterial growth curve by measuring absorbance on bacterial culture over time.
Measured: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: diabetic wounds
Bacterial growth curve by measuring absorbance on bacterial culture over time.
Measured: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: blood cultures
Bacterial growth curve by measuring absorbance on bacterial culture over time.
Measured: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: nasal carriage
Bacterial growth curve by measuring absorbance on bacterial culture over time.
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: osteitis
The rate of internalisation and release of LDH (a sign of cellular toxicity of the bacterial isolate) in an in vitro osteoblast cell culture model (MC3T3-E1)
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: intracellular bacterial multiplication of S. pettenkoferi strains from osteitis
The amount of intracellular bacterial multiplication will be assessed in an in vitro macrophage cell culture model (RAW 264.7).
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: diabetic wounds
The rate of internalisation and release of LDH (a sign of cellular toxicity of the bacterial isolate) in an in vitro osteoblast cell culture model (MC3T3-E1)
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: intracellular bacterial multiplication of S. pettenkoferi strains from diabetic wounds
The amount of intracellular bacterial multiplication will be assessed in an in vitro macrophage cell culture model (RAW 264.7).
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: blood cultures
The rate of internalisation and release of LDH (a sign of cellular toxicity of the bacterial isolate) in an in vitro osteoblast cell culture model (MC3T3-E1)
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains:intracellular bacterial multiplication of S. pettenkoferi strains from blood cultures
The amount of intracellular bacterial multiplication will be assessed in an in vitro macrophage cell culture model (RAW 264.7).
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: nasal carriage
The rate of internalisation and release of LDH (a sign of cellular toxicity of the bacterial isolate) in an in vitro osteoblast cell culture model (MC3T3-E1)
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains:intracellular bacterial multiplication of S. pettenkoferi strains from nasal carriage
The amount of intracellular bacterial multiplication will be assessed in an in vitro macrophage cell culture model (RAW 264.7).
Measured: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: survival time of diabetic zebrafish immersed in S. pettenkoferi strains from osteitis
Survival curve at 48 hours
Measured: Up to 48 hours
Virulence profiles according to sample origin in a sub-sample of 3 strains: survival time of diabetic zebrafish immersed in S. pettenkoferi strains from non-diabetic wounds
Survival curve at 48 hours
Measured: Up to 48 hours
Virulence profiles according to sample origin in a sub-sample of 3 strains: survival time of diabetic zebrafish immersed in S. pettenkoferi strains from diabetic wounds
Survival curve at 48 hours
Measured: Up to 48 hours
Virulence profiles according to sample origin in a sub-sample of 3 strains: survival time of diabetic zebrafish immersed in S. pettenkoferi strains from blood cultures
Survival curve at 48 hours
Measured: Up to 48 hours
Virulence profiles according to sample origin in a sub-sample of 3 strains: survival time of diabetic zebrafish immersed in S. pettenkoferi strains from nasal carriage
Survival curve at 48 hours
Measured: Up to 48 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Nov 2024
- Study start1 Jan 2024
- Primary completion31 Dec 2025
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Diabetic Foot UlcerStudies of the same condition, open and under way.
- More trials run by Centre Hospitalier Universitaire de NīmesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Other
- Enrolment
- 230 participants (actual)
- Target duration
- 2 Years
Sponsor and investigators
- Lead sponsor
- Centre Hospitalier Universitaire de Nīmes
- Sponsor type
- University, hospital or other
- Collaborators
- Staphylococcal National Reference Center, Lyon, France, Rennes University Hospital, Nantes University Hospital, Universität Tübingen, Örebro University, Sweden, Charles University, Czech Republic, University Hospital Muenster
- Responsible party
- Sponsor
- Investigators
- Chloé MAGNAN, Dr., Principal investigator, Nîmes University Hospital, FRANCE
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06688084
- Sponsor's protocol ID
- NIMAO/2023-2/CM-01
- Acronym
- PETTENK-OS
- Status last verified
- Sep 2026
- First submitted
- 9 Nov 2024
- Last updated
- 25 Sep 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Magnan C, Curtil-Dit-Galin M, Morsli M, Cattoir V, Piau-Couapel C, Soderquist B, Kahl BC, Denis O, Rwayane K, Corvec S, Francois P, Salipante F, Pantel A, Dunyach-Remy C, Laurent F, Lavigne JP; European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Staphylococci and Staphylococcal Diseases (ESGS). Staphylococcus pettenkoferi: an underrecognized species with clinically relevant antimicrobial resistance. A comprehensive genomic European study. Emerg Microbes Infect. 2026 Dec;15(1):2724635. doi: 10.1080/22221751.2026.2724635. Epub 2026 Sep 16.
PubMed 42748359Magnan C, Plumet L, Morsli M, Dunyach-Remy C, Pouget C, Sotto A, Molle V, Lavigne J-P. A narrative review of coagulase-negative staphylococci in diabetic foot infections. Clin Microbiol Rev. 2025 Dec 11;38(4):e0012125. doi: 10.1128/cmr.00121-25. Epub 2025 Nov 4.
PubMed 41186420
Study at a glance
From the registry record, last updated by the sponsor on 25 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Pathogenicity Factors of Staphylococcus Pettenkoferi in Foot Wounds and Osteitis in Diabetic Patients
- ClinicalTrials.gov ID
- NCT06688084
- Acronym / sponsor ID
- PETTENK-OS / NIMAO/2023-2/CM-01
- Conditions
- Diabetic Foot Ulcer
- Keywords
- Diabetes, Foot, Infection, Staphylococcus pettenkoferi, Osteitis
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 230 participants (actual)
- Lead sponsor
- Centre Hospitalier Universitaire de NīmesUniversity, hospital or other
- Collaborators
- Staphylococcal National Reference Center, Lyon, France, Rennes University Hospital, Nantes University Hospital, Universität Tübingen, Örebro University, Sweden, Charles University, Czech Republic, University Hospital Muenster
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 31 Dec 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 14 Nov 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Gram-positive cocci, particularly Staphylococcus aureus and coagulase-negative staphylococci (SCoN), are the bacteria most frequently isolated from diabetic foot ulcers. Although studies have been carried out on the role of S. aureus in the unfavorable evolution of these wounds, no studies have focused on the role of SCoN. Of the fifty or so SCoN species, not all have the same virulence potential. The role of Staphylococcus pettenkoferi is unknown, yet this bacterium is the 7th most frequently identified in diabetic foot ulcers, suggesting that it may also be involved in the pathophysiology of these infections. At Nîmes University Hospital, this bacterium is mainly identified in samples from diabetic foot ulcers or osteitis in our laboratory and 80% of the bacteria present are in biofilms.It is essential to understand the mechanisms governing these bacterial interactions and establish the true pathogenic potential of these bacteria. Recently, the Nîmes team showed that a strain of S. pettenkoferi (SP165) isolated from foot osteitis in a diabetic patient had real virulence potential. SP165 could not only produce biofilm, but could also survive in human blood, human keratinocytes and murine and human macrophages. It also caused significant embryonic mortality in a zebrafish model. A second study of 29 isolates from Nîmes University Hospital subsequently demonstrated that there were two predominant clones with different virulences. Three biofilm production profiles (rapidly and highly biofilm-producing, slowly biofilm-producing and non-biofilm-producing) and two zebrafish profiles (highly and moderately lethal) were reported by phenotypic and genomic analyses on this panel of strains. Genes for resistance, virulence and biofilm production were also found on their genomes.
Detailed description
Gram-positive cocci, in particular Staphylococcus aureus and coagulase-negative staphylococci (SCoN), are the bacteria most frequently isolated from diabetic foot ulcers. While studies have been carried out on the role of S. aureus in the unfavorable evolution of these wounds, no study has focused on the role of SCoN. Of the fifty or so SCoN species, not all have the same virulence potential. The role of Staphylococcus pettenkoferi is not known. Yet this bacterium is the 7th most frequently identified in diabetic foot ulcers, suggesting that it may also be involved in the pathophysiology of these infections. In the work of Loetsche et al. a study of the microbiome of 349 diabetic foot ulcer samples by targeted 16S rDNA sequencing showed that the genus Staphylococcus was the most abundant, with a relative abundance of 22.8%, including 13.3% S. aureus and 5.3% S. pettenkoferi.
At Nîmes University Hospital, this bacterium is mainly identified in samples from diabetic foot ulcers or osteitis in our laboratory (89 isolations of S. pettenkoferi from diabetic foot ulcer samples out of 167 isolations made of this bacterium between 2018 and 2022).The difficulty of managing chronic wounds also lies in the fact that almost 80% of the bacteria present are in biofilms. It has also been established that the environment in which bacteria are found, and in particular the interactions they establish between themselves, play a significant role in delayed wound healing. It is therefore essential to understand the mechanisms governing these bacterial interactions and to establish the true pathogenic potential of these bacteria.
Recently, our team demonstrated that a strain of S. pettenkoferi (SP165) isolated from foot osteitis in a diabetic patient had real virulence potential. As well as being able to produce biofilm, SP165 was able to survive in human blood, human keratinocytes and murine and human macrophages. It also demonstrated its virulence by causing significant embryonic mortality in the zebrafish model.
A second study of 29 isolates from Nîmes University Hospital subsequently demonstrated the existence of two predominant clones with different virulences.
Three biofilm production profiles (rapidly and highly biofilm-producing, slowly biofilm-producing and non-biofilm-producing) and two zebrafish virulence profiles (highly and moderately lethal) were reported by phenotypic and genomic analyses on this panel of strains. Genes for resistance, virulence and biofilm production were also found on their genomes.
Study design
- Observational model
- Cohort
- Time perspective
- Other
- Target follow-up
- 2 Years
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- The collection of strains at the Nîmes University Hospital site from 9 European laboratories collected between 2015 and 2023 for a total of 108 months was carried out between November 2021 and August 2023.
Key inclusion criteria (1 listed)
- Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi
Key exclusion criteria (1 listed)
- Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Molecular epidemiology of the collectionNext-generation genomic sequencing (MICRO\&BIO platform, MiSeq, Illumina) and bioinformatics analyses. After validating data quality, genomes will be re-assembled using Spades software (version 3.15.4) and CLC® (Qiagen), then compared with the National Center for Biotechnology Information GenBank database. They will also be analysed on the online Type-Strain Genomes Server platform to accurately identify the bacteria. Genome annotation will be done using the DDBJ Fast Annotation and Submission Tool. Single nucleotide polymorphisms (SNP) analysis based on the alignment of whole genomes and core-genomes will be carried out using version 7 of MAFFT (multiple alignment using fast Fourier transform) software, then quantified using snp-dists (version 0.6.3). This approach will enable the molecular epidemiology of the collection of strains in France and other European countries to be clarified, and the main circulating clades to be assessed, particularly depending on the origin of samples. | Other | – |
| Study of the resistome of the S. pettenkoferi populationThe resistome will be assessed by identifying known and described resistance genes in staphylococci using bioinformatics analyses of sequenced complete bacterial genomes. A search for plasmids will also be made using various specific software packages (ResFinder, CARD, PointFinder, Plasmidfinder, in-house pipeline). | Other | – |
| Study of the virulome of the S. pettenkoferi populationThe virulome of the strains will be studied based on the genomic sequencing data obtained and with reference to the literature on Staphylococci. Various specific software packages (Pathogenfinder, Virulencefinder, in-house pipeline) will be used for this purpose. | Other | – |
| Study of the resistance profiles of all S. pettenkoferi isolatesAntibiotic resistance will be assessed using a Sensititer® plate (Thermo ScientificTM, Illkirch) to evaluate the minimum inhibitory concentration of isolates against a series of antibiotics commonly used for S. pettenkoferi infections, including new molecules currently on the market or in development, such as Ceftaroline, Ceftobiprole, Dalbavancin, Delafloxacin, Tedizolid and Oritavancin. Minimum inhibitory concentration values will be interpreted in accordance with the recommendations of the Antibiogram Committee of the Société Française de Microbiologie (https://www.sfm-microbiologie.org/2021/04/23/casfm-avril-2021-v1-0/). | Other | – |
| Selection of strains for in-depth phenotypic studyDifferent strains of S. pettenkoferi isolated from foot osteitis in diabetic patients and non-diabetic osteitis will be selected according to the clades identified and phenotypically characterised by further analysis: * Observation of culture characteristics (culture requirements, growth time, colony size and haemolytic capacity), (n=20) * Determination of growth curves by measuring absorbance at 600 nm using the Infinite M Mano automatic absorbance reader (TECAN, Lyon), (n=20) * Study of the ability to form biofilm in the presence (antibiofilmogram) (n=85) or absence (BioFilm Ring® test, Biofilm Control, St Beauzire) (n=85) of various antibiotics commonly used for the treatment of S. pettenkoferi infection during osteitis. | Other | – |
| Selection of strains (n=3) for the virulence studyThree strains of S. pettenkoferi isolated from foot osteitis in diabetic patients will be selected on the basis of the clades identified and the study of the virulome in order to be analysed on : * In vitro cell culture models of macrophages (RAW 264.7) and osteoblasts (MC3T3-E1) to assess the invasion potential of these isolates by measuring internalisation rates (TECAN, Lyon) and LDH release (CyQUANT LDH Cytotoxicity kit), a sign of cellular toxicity of the isolate. * An in vivo wound model on diabetic zebrafish (Dario rerio) with evaluation of their survival at 48h in the presence of the isolates by immersion. These models were developed at the MICRO\&BIO Platform and the INSERM 1047 VBIC unit. | Other | – |
Primary outcome
Genetic diversity of Staphyloccocus pettenkoferi strains isolated from osteitis and non-diabetic wounds, blood cultures and nasal carriage.
Time frame: Day 0 to 3 months
Number of clades estimated via typing by complete sequencing of the bacterial genomes of all S. pettenkoferi strains and analysis of phylogenetic distances (whole genome and core genome single nucleotide polymorphisms).
45 secondary outcomes
Genetic diversity of Staphyloccocus pettenkoferi strains isolated from osteitis and non-diabetic wounds, blood cultures and nasal carriage.
Time frame: 3 - 6 months
Resistome in the strain population according to sample origin:osteitis
Time frame: 3 - 6 months
Resistome in the strain population according to sample origin: non-diabetic wounds
Time frame: 3 - 6 months
Resistome in the strain population according to sample origin: diabetic wounds
Time frame: 3 - 6 months
Resistome in the strain population according to sample origin: blood cultures
Time frame: 3 - 6 months
Resistome in the strain population according to sample origin: nasal carriage
Time frame: 3 - 6 months
Virulome in the strain population according to sample origin: osteitis
Time frame: 3 - 6 months
Virulome in the strain population according to sample origin: non-diabetic wounds
Time frame: 3 - 6 months
Virulome in the strain population according to sample origin: diabetic wounds
Time frame: 3 - 6 months
Virulome in the strain population according to sample origin: blood cultures
Time frame: 3 - 6 months
Virulome in the strain population according to sample origin: nasal carriage
Time frame: 3 - 6 months
Plasmids inthe strain population and according to sample origin: osteitis
Time frame: 3 - 6 months
Plasmids inthe strain population and according to sample origin: non-diabetic wounds
Time frame: 3 - 6 months
Plasmids inthe strain population and according to sample origin: diabetic wounds
Time frame: 3 - 6 months
Plasmids inthe strain population and according to sample origin: blood cultures
Time frame: 3 - 6 months
Plasmids inthe strain population and according to sample origin: nasal carriage
Time frame: 3 - 6 months
Phenotypic resistance profiles in the population in a subsample of 85 strains
Time frame: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: osteitis
Time frame: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: non-diabetic wounds
Time frame: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: diabetic wounds
Time frame: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: blood cultures
Time frame: 6 - 14 months
Phenotypic resistance profiles in the population and according to sample origin: nasal carriage
Time frame: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: osteitis
Time frame: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: non-diabetic wounds
Time frame: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: diabetic wounds
Time frame: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: blood cultures
Time frame: 6 - 14 months
Amount of biofilm formation in the absence and presence of antibiotics in a selection (85 sub-samples) of S. pettenkoferi strains according to sample origine: nasal carriage
Time frame: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: osteitis
Time frame: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: non-diabetic wounds
Time frame: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: diabetic wounds
Time frame: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: blood cultures
Time frame: 6 - 14 months
Bacterial growth rate according to sample origin in a sub-sample of 20 strains: nasal carriage
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: osteitis
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: intracellular bacterial multiplication of S. pettenkoferi strains from osteitis
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: diabetic wounds
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: intracellular bacterial multiplication of S. pettenkoferi strains from diabetic wounds
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: blood cultures
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains:intracellular bacterial multiplication of S. pettenkoferi strains from blood cultures
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains: nasal carriage
Time frame: 6 - 14 months
Virulence profiles according to sample origin in a sub-sample of 3 strains:intracellular bacterial multiplication of S. pettenkoferi strains from nasal carriage
Time frame: 6 - 14 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Sep 2026.
- Background: PubMed 42748359Magnan C, Curtil-Dit-Galin M, Morsli M, Cattoir V, Piau-Couapel C, Soderquist B, Kahl BC, Denis O, Rwayane K, Corvec S, Francois P, Salipante F, Pantel A, Dunyach-Remy C, Laurent F, Lavigne JP; European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Staphylococci and Staphylococcal Diseases (ESGS). Staphylococcus pettenkoferi: an underrecognized species with clinically relevant antimicrobial resistance. A comprehensive genomic European study. Emerg Microbes Infect. 2026 Dec;15(1):2724635. doi: 10.1080/22221751.2026.2724635. Epub 2026 Sep 16.
- Results publication: PubMed 41186420Magnan C, Plumet L, Morsli M, Dunyach-Remy C, Pouget C, Sotto A, Molle V, Lavigne J-P. A narrative review of coagulase-negative staphylococci in diabetic foot infections. Clin Microbiol Rev. 2025 Dec 11;38(4):e0012125. doi: 10.1128/cmr.00121-25. Epub 2025 Nov 4.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Chloé MAGNAN, Dr. principal investigator
Nîmes University Hospital, FRANCE
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Diabetic Foot Ulcer, run by Centre Hospitalier Universitaire de Nīmes at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 25 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Genetic diversity of Staphyloccocus pettenkoferi strains isolated from osteitis and non-diabetic wounds, blood cultures and nasal carriage. (time frame: Day 0 to 3 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06688084, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Sep 2026.