Staphylokinase and ABO Group Phenotype: New Players in Staphylococcus Aureus Implant-associated Infections Development

The purpose of this study is to identify bacterial and/or clinical features involved in the pathogenesis of Staphylococcus aureus implant-associated infections (IAI). Materials & methods: In total, 57 IAI S. aureus and 31 nasal carriage (NC) S. aureus isolates were studied. Staphylococcus aureus genetic background was obtained by microarray analysis. Multilocus sequence typing was performed to determine clonal complexes (CC). Biofilm production was investigated by resazurin and crystal violet methods

Study Overview

• Status: Completed
• Conditions: Staphylococcal Infection
• Intervention / Treatment: Other: IAI infection; Other: Staphylococcus aureus nasal carriage infection

• Study Type: Observational
• Enrollment (Actual): 88

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: ADULT; OLDER_ADULT; CHILD
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Fifty-five IAI patients were included; two of them had two different S. aureus IAI episodes. The median age was 73 years (range: 21-96 years) with 29 women (52.7%). Twenty seven percent of patients suffered from diabetes and were smokers.

Nine patients including six women were immunosuppressed with a median age of 71 years. The main diagnosis for arthroplasty was arthrosis (38%). Implants were hip prosthesis (n = 35), knee prosthesis (n = 18) and osteosynthesis (n = 4). Main local consequences of IAI were scarce alteration (n = 34) and skin fistulization (n = 22). These IAI were treated by surgical removal of all infected tissue and implant or a combination of debridement with implant retention associated to long-term antimicrobial therapy active against biofilm microorganisms. Eighteen early, nine delayed and 30 late infections occurred. Blood group phenotypes were available for 54 patients and were distributed as follows: 26 O group, 17 A group, 10 B group and one AB group.

Description

Inclusion Criteria:

• infected patients with S. Aureus IAI infection
• noninfected patients screened for S. aureus nasal colonization at the orthopedic consultation ward

Exclusion Criteria:

• minor

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
IAI patients group; patients with Staphylococcus aureus of implant-associated infections	Other: IAI infection
control group; patients with Staphylococcus aureus nasal carriage	Other: Staphylococcus aureus nasal carriage infection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
biofilm production measurement in the two groups	The primary aim of this study is to identify phenotypic (biofilm production) markers in two different groups of S. aureus strains isolated from patients with IAI or screened from nasal carrier in noninfected patients undergoing orthopedic surgery. By using resazurin method, IAI and NC nasal carriage isolates were divided into three groups. Isolates were classified as strong, moderate and weak biofilm producers.	september 2012
Clonal complexes distribution	The primary aim of this study is to identify genotypic markers in two different groups of S. aureus strains isolated from patients with IAI or screened from nasal carrier in noninfected patients undergoing orthopedic surgery. IAI and NC isolates genetic background was determined in order to compare the prevalence of individual virulence factor genes. All genes provided by the Alere StaphyType DNA microarray were studied.	september 2012
IAI and NC nasal carriage isolates genetic background	IAI and NC isolates genetic background was determined in order to compare the prevalence of individual virulence factor genes. All genes provided by the Alere StaphyType DNA microarray were studied	september 2012

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
biofilm production correlation with genotype	quantile-quantile (QQ)-plot analysis	december 2013
Correlation between Clonal Complexes distribution , genotype and clinical parameters	In order to determine whether clusters of S. aureus could be associated with clinical characteristics of the patients, search of association between CCs and clinical data was performed	december 2013
Association of ABO group phenotype and IAI S. aureus genotype	QQ-plots analysis	december 2013

Collaborators and Investigators

• Sponsor: Nantes University Hospital

Study record dates

Study Major Dates

• Study Start: February 1, 2012
• Primary Completion (ACTUAL): September 1, 2012
• Study Completion (ACTUAL): December 1, 2013

Study Registration Dates

• First Submitted: June 16, 2016
• First Submitted That Met QC Criteria: June 23, 2016
• First Posted (ESTIMATE): June 24, 2016

Study Record Updates

• Last Update Posted (ESTIMATE): June 24, 2016
• Last Update Submitted That Met QC Criteria: June 23, 2016
• Last Verified: June 1, 2016

More Information

Terms related to this study

• Keywords: Staphylococcus aureus; biofilm; microarrays; bone and joint infection; staphylokinase; bone binding sialoprotein; blood group
• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Bacterial Infections; Bacterial Infections and Mycoses; Gram-Positive Bacterial Infections; Infections; Communicable Diseases; Staphylococcal Infections
• Other Study ID Numbers: RC15_0456

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO