Pathogenicity Factors of Staphylococcus Pettenkoferi in Foot Wounds and Osteitis in Diabetic Patients (PETTENK-OS)

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Diabetic Foot Ulcer
• Intervention / Treatment: Other: Molecular epidemiology of the collection; Other: Study of the resistome of the S. pettenkoferi population; Other: Study of the virulome of the S. pettenkoferi population; Other: Study of the resistance profiles of all S. pettenkoferi isolates; Other: Selection of strains for in-depth phenotypic study; Other: Selection of strains (n=3) for the virulence study

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 Type: Observational
• Enrollment (Actual): 230

Contacts and Locations

Study Locations

• France
  • Gard
    • Nîmes, Gard, France, 30029
      • Nimes University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

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.

Description

Inclusion Criteria:

• Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi

Exclusion Criteria:

• Not applicable for this research on a ready-constituted collection of strains of Staphylococcus pettenkoferi

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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).	Day 0 to 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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	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	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	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	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	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.	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.	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.	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.	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.	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)	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).	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)	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).	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)	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).	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)	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).	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	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	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	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	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	Up to 48 hours

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire de Nīmes
• Collaborators: Charles University, Czech Republic; University Hospital Muenster; Rennes University Hospital; Nantes University Hospital; Örebro University, Sweden; Universität Tübingen; Staphylococcal National Reference Center, Lyon, France
• Investigators: Principal Investigator: Chloé MAGNAN, Dr., Nîmes University Hospital, France

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2024
• Primary Completion (Estimated): December 31, 2025
• Study Completion (Estimated): May 1, 2026

Study Registration Dates

• First Submitted: November 9, 2024
• First Submitted That Met QC Criteria: November 12, 2024
• First Posted (Actual): November 14, 2024

Study Record Updates

• Last Update Posted (Actual): November 17, 2025
• Last Update Submitted That Met QC Criteria: November 14, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Diabetes; Infection; Foot; Osteitis; Staphylococcus pettenkoferi
• Additional Relevant MeSH Terms: Endocrine System Diseases; Bone Diseases; Musculoskeletal Diseases; Vascular Diseases; Cardiovascular Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetic Angiopathies; Diabetes Complications; Skin Diseases; Skin Ulcer; Leg Ulcer; Diabetic Neuropathies; Foot Ulcer; Nutritional and Metabolic Diseases; Skin and Connective Tissue Diseases; Diabetes Mellitus; Infections; Diabetic Foot; Osteitis
• Other Study ID Numbers: NIMAO/2023-2/CM-01

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No