Rifabutin versus rifampicin bactericidal and antibiofilm activities against clinical strains of Staphylococcus spp. isolated from bone and joint infections

Periprosthetic Joint Infection: Current Clinical Challenges

Over the last several decades, periprosthetic joint infection has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of periprosthetic joint infection, focusing on frequent clinical challenges and collaborative interdisciplinary care.

Antibody-Functionalized Polymer Nanoparticles for Targeted Antibiotic Delivery in Models of Pathogenic Bacteria Infecting Human Macrophages

The efficacy of antibody-functionalized poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs), prepared by nanoprecipitation, carrying rifampicin (RIF) against planktonic, sessile, and intracellular Staphylococcus aureus and Escherichia coli is reported here. A biotinylated anti-S. aureus polyclonal antibody, which binds to structural antigens of the whole bacterium, was functionalized on the surface of RIF-loaded PLGA-based NPs by using the high-affinity avidin-biotin complex. This general strategy allows the binding of commercially available biotinylated antibodies. Coculture models of S. aureus ATCC 25923 and Escherichia coli S17 were used to demonstrate the preferential selectivity of the antibody-functionalized NPs against the Gram-positive bacterium only. At 0.2 μg/mL, complete S. aureus eradication was observed for the antibody-functionalized RIF-loaded NPs, whereas only a 5-log reduction was observed for the nontargeted RIF-loaded NPs. S. aureus is a commensal facultative pathogen having part of its live cycle intracellularly in both phagocytic and nonphagocytic cells. Those intracellular bacterial persisters, named small colony variants, have been postulated as reservoirs of relapsed episodes of infection and consequent treatment failure. At 0.5 μg/mL, the RIF-loaded NPs reduced in 2-log intracellular S. aureus-infecting human macrophages. The ability of those antibody-functionalized nanoparticles to prevent biofilm formation or to reduce the bacterial burden in already-formed mature biofilms is also reported here using S. aureus and E. coli single and cocultured biofilms. In the prevention of S. aureus biofilm formation, the antibody-functionalized NPs exerted a superior inhibition of bacterial growth (up to 2 logs) compared to the nonfunctionalized ones. This study demonstrates the selectivity of the synthesized immunonanoparticles and their antimicrobial efficacy in different scenarios, including planktonic cultures, sessile conditions, and even against intracellular infective pathogens.

Do Anti-Biofilm Antibiotics Have a Place in the Treatment of Diabetic Foot Osteomyelitis?

The choice of antibiotic regimens for use in patients presenting with diabetic foot osteomyelitis and their duration differs according to the situation. Antibiotics play a more important role in the medical option where no infected bone has been resected, while their role is reduced but not negligible in the case of surgical options. Some studies have reported the presence of biofilm structures in bone samples taken from patients with diabetic foot osteomyelitis, which raises the question of the place of anti-biofilm antibiotic regimens in this setting. During the last two decades, clinical studies have suggested a potential benefit for anti-biofilm antibiotics, mainly rifampicin against staphylococci and fluoroquinolones against gram-negative bacilli. However, no data from randomized controlled studies have been reported so far. The present work provides a summary of the available data on the question of the place of anti-biofilm antibiotics for the treatment of diabetic foot osteomyelitis, but also the potential limitations of such treatments.

Rifampicin resistance and risk factors associated with significantly lower recovery rates after two stage revision in patients with prosthetic joint infection

PURPOSE

Rifampicin plays a key role in the management of prosthetic joint infections (PJIs), however, the emergence of rifampicin resistance is associated with less favorable clinical outcomes. The purpose of this study was to investigate the impact of rifampicin resistance and other patient-related factors on recovery rates among patients with PJI undergoing two-stage revision.

METHODS

We reviewed medical records and microbiology reports of 73 patients (41 males and 32 females) undergoing two-stage revision due to PJI between 2017 and 2019. Patient-specific data, co-morbidities and the antibiotic resistance of microbiological isolates were registered. 48 patients had hip, 22 had knee, 2 had shoulder and 1 had elbow joint infection. Obtained data were statistically analyzed with a logistic regression model.

RESULTS

Rifampicin-sensitive organism was isolated in 53 cases (72.6%). Recovery rate was 92.5% in the sensitive and 60.0% in the resistant group. We observed that rifampicin resistance significantly reduced the probability of recovery. Furthermore, in the rifampicin-sensitive group, the probability of recovery decreased with advancing age with a significant drop above the age of 60 years. The effect of age is negligible in the rifampicin-resistant group. We also found that type 2 diabetes mellitus has a negative effect on recovery. Coagulase-negative Staphylococci were predominant in the rifampicin-sensitive (50% of the isolates) and Gram-negative rods in the resistant group (40%).

CONCLUSIONS

Rifampicin resistance was associated with lower recovery rates among patients undergoing two-stage revision due to PJI. Higher age and type 2 diabetes mellitus had negative impact on clinical outcome.