Successful Treatment of Polymicrobial Calcaneal Osteomyelitis with Telavancin, Rifampin, and Meropenem

Comparing the efficacy of different antibiotic regimens on osteomyelitis: A network meta-analysis of animal studies

Background

Despite the surge in the number of antibiotics used to treat preclinical osteomyelitis (OM), their efficacy remains inadequately assessed.

Objective

To establish network comparisons on the efficacy of antibiotic regimens on OM in animal studies.

Methods

PubMed, Embase, Web of Science, and The Cochrane Library were searched from inception to March 2022 for relevant articles. Odds ratios (ORs) were generated for dichotomous variants, and the standard mean difference (SMD) was calculated for constant variables. The predominant outcomes were the effective rate of sterility, also known as sterility rates, as well as the bacterial counts at the end of the experiments and antibiotic concentrations in serum or bone. All the network meta-analyses were performed using STATA MP 16.0. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; no. CRD42022316544).

Results

A total of 28 eligible studies with 1,488 animals were included for data analysis, including 13 antibiotic regimens. Regarding the effective rate of sterility, glycopeptides (GLY), linezolid (LIN), rifampicin (RIF)+β-Lactam, and β-Lactam showed significant efficacy compared with placebo (OR ranging from 0.01 to 0.08). For radiological grade, only RIF+GLY (SMD: −5.92, 95%CI: −11.65 to −0.19) showed significant efficacy compared with placebo. As for reducing bacteria count, fosfomycin (FOS), tigecycline (TIG), GLY, LIN, RIF, RIF+β-Lactam, RIF+GLY, aminoglycosides (AMI), and clindamycin (CLI) showed significant efficacy compared with placebo (SMD ranging from −6.32 to −2.62). Moreover, the bone concentrations of GLY were higher 1 h after administration and the higher blood concentrations were higher after 1 h and 4 h compared with the other antibiotics.

Conclusion

Multiple antibiotic regimens showed significant efficacy in animals with OM, including increasing effective rates of sterility, reducing bacterial counts, and lowering radiological scores. Among them, RIF+GLY was the most promising treatment regimen owing to its optimal efficacy. Based on the preclinical studies included in our meta-analysis, head-to-head clinical randomized controlled trials are required to confirm these findings in humans.

Telavancin for the treatment of methicillin-resistant Staphylococcus aureus bone and joint infections

This retrospective, case series describes our experience with the use of telavancin in patients with methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis and prosthetic joint infection. The primary objectives were clinical outcomes and adverse events (AEs), and a secondary outcome described microbiological susceptibility. Fourteen patients were enrolled. Median duration of therapy was 58 days, and four patients had concurrent bacteremia. End-of-treatment outcomes were available in 78% of patients, with a clinical success rate of 91%. Thirty-day and 12-month outcomes were also obtained. Seven patients experienced AEs. Infusion-related reactions were most common, and three AEs required discontinuation of therapy. All MRSA isolates had a telavancin MIC ≤0.06μg/ml, which is susceptible. This study indicates that telavancin may have a role in treatment of MRSA osteomyelitis and prosthetic joint infection. Our study describes clinical success and adverse events for long duration of therapy, up to 8 weeks.

Outpatient treatment of osteomyelitis with telavancin

Telavancin is a lipoglycopeptide antibiotic with bactericidal activity against Gram-positive pathogens including Staphylococcus aureus, the most frequent cause of osteomyelitis. Treatment is often challenging due to needs for surgical intervention along with prolonged administration of intravenous antimicrobials, frequently in an outpatient setting. This was a retrospective analysis of the efficacy and safety of telavancin for treatment of osteomyelitis provided as outpatient parenteral antimicrobial therapy (OPAT) in physician office infusion centres. Medical records of 60 patients receiving telavancin for osteomyelitis in 22 physician office infusion centres from 2010 to 2011 and 2013 to 2015 were reviewed. Of these, 60% were treated without hospitalisation, 37% had orthopaedic hardware and 56% had concurrent infections. Staphylococcus aureus was the most common pathogen (78%), primarily methicillin-resistant. The median duration of telavancin treatment in the outpatient setting was 21 days (range 3-105 days). Telavancin was used as first-line therapy in 32% of cases, following prior antibiotic failure in 47% and due to intolerance to previous agents in 22%, predominantly daptomycin or vancomycin. The telavancin dose was 10 mg/kg/day, adjusted for renal function in 25% of patients. The majority of patients self-administered telavancin at home via an elastomeric infusion pump. Overall clinical success was 73%. No significant differences in outcomes were observed with the presence of hardware, concurrent infection, concomitant therapies or type of osteomyelitis. Telavancin-associated adverse events occurred in 57%, with discontinuation in three patients (5%). These data demonstrate the effective and safe OPAT use of telavancin, providing an alternative for successful treatment of patients with osteomyelitis.

Activity of telavancin against Gram-positive pathogens isolated from bone and joint infections in North American, Latin American, European and Asia-Pacific nations

Telavancin was tested against a worldwide collection of Gram-positive pathogens (967) isolated from bone and joint infections (BJI). Most BJI isolates were from the United States (US) (49.9%) followed by Europe (26.4%), Latin America (LATAM; 14.4%), and Asia-Pacific (APAC; 9.3%). Organisms were tested by broth microdilution susceptibility methods. S. aureus (66.4%; range of 48.9% in APAC to 71.2% in LATAM) was the most common pathogen and had a 35.7% methicillin resistance (MRSA) rate and telavancin MIC_50/90 of 0.03/0.06μg/mL (100% susceptible). MRSA isolates that were daptomycin resistant (0.2%) were telavancin susceptible. CoNS (12.1% of BJI) had telavancin MIC_50/90 at 0.06/0.06μg/mL, and 13.7% were teicoplanin resistant. Enterococci had telavancin MIC_50/90 at 0.12/0.25μg/mL, but telavancin inhibited vancomycin-susceptible isolates at ≤0.25μg/mL. All streptococci were telavancin susceptible (MIC₉₀, 0.03-0.06μg/mL). The in vitro results presented here warrant further investigations to access the role of telavancin for BJI/osteomyelitis treatment caused by Gram-positive cocci.

Clinical Effectiveness, Safety Profile, and Pharmacokinetics of Daptomycin in Pediatric Patients: A Systematic Review

Infections by Gram-positive pathogens pose a public health risk, especially due to increasing antibiotic resistance. Daptomycin has efficacy against most clinically important Gram-positive bacteria. Although experience regarding use of daptomycin in adults is increasing, studies on pediatric populations are limited. We aimed to evaluate the efficacy, safety, and pharmacokinetics of daptomycin in pediatric settings. We searched MEDLINE and Clinicaltrials.gov (through April 2016) and included 29 original studies in the final analysis. Available evidence suggests that daptomycin in pediatric patients has a favorable safety and tolerability profile and is an efficacious alternative for treatment of Gram-positive bacteremia, endocarditis, and infections of the skin, soft tissues, joints, and bones, especially when resistant strains are involved. However, future studies need to address several issues to determine the optimal dose and various pharmacokinetic parameters in different pediatric age groups.

New Is Old, and Old Is New: Recent Advances in Antibiotic-Based, Antibiotic-Free and Ethnomedical Treatments against Methicillin-Resistant Staphylococcus aureus Wound Infections

Staphylococcus aureus is the most common pathogen of wound infections. Thus far, methicillin-resistant S. aureus (MRSA) has become the major causative agent in wound infections, especially for nosocomial infections. MRSA infections are seldom eradicated by routine antimicrobial therapies. More concerning, some strains have become resistant to the newest antibiotics of last resort. Furthermore, horizontal transfer of a polymyxin resistance gene, mcr-1, has been identified in Enterobacteriaceae, by which resistance to the last group of antibiotics will likely spread rapidly. The worst-case scenario, "a return to the pre-antibiotic era", is likely in sight. A perpetual goal for antibiotic research is the discovery of an antibiotic that lacks resistance potential, such as the recent discovery of teixobactin. However, when considering the issue from an ecological and evolutionary standpoint, it is evident that it is insufficient to solve the antibiotic dilemma through the use of antibiotics themselves. In this review, we summarized recent advances in antibiotic-based, antibiotic-free and ethnomedical treatments against MRSA wound infections to identify new clues to solve the antibiotic dilemma. One potential solution is to use ethnomedical drugs topically. Some ethnomedical drugs have been demonstrated to be effective antimicrobials against MRSA. A decline in antibiotic resistance can therefore be expected, as has been demonstrated when antibiotic-free treatments were used to limit the use of antibiotics. It is also anticipated that these drugs will have low resistance potential, although there is only minimal evidence to support this claim to date. More clinical trials and animal tests should be conducted on this topic.

In Vitro Pharmacodynamics of Human Simulated Exposures of Telavancin against Methicillin-Susceptible and -Resistant Staphylococcus aureus with and without Prior Vancomycin Exposure

Telavancin is a lipoglycopeptide with potent activity against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). The activity of telavancin against MRSA and MSSA after prior vancomycin exposure was studied in an in vitro pharmacodynamic model. Two clinical MRSA and two MSSA isolates, all with vancomycin MICs of 2 μg/ml, were subjected to humanized free drug exposures of vancomycin at 1 g every 12 h (q12h) for 96 h, telavancin at 750 mg q24h for 96 h, and vancomycin at 1 g q12h for 72 h followed by telavancin at 750 mg q24h for 48 h (120 h total). The microbiological responses were measured by changes from 0 h in log10 CFU/ml at the end of experiments and area under the bacterial killing and regrowth curves over 96 h (AUBC0-96). The control isolates grew to 8.8 ± 0.3 log10 CFU/ml. Initially, all regimens caused -4.5 ± 0.9 reductions in log10 CFU/ml by 48 h followed by slight regrowth over the following 48 to 72 h. After 96 h, vancomycin and telavancin achieved -3.7 ± 0.9 and -3.8 ± 0.8 log10 CFU/ml changes from baseline, respectively (P = 0.74). Sequential exposure to telavancin after vancomycin did not result in additional CFU reductions or increases, with ultimate log10 CFU/ml reductions of -4.3 ± 1.1 at 96 h and -4.2 ± 1.3 at 120 h (P > 0.05 for all comparisons at 96 h). The AUBC0-96 was significantly smaller for the regimen of telavancin for 96 h than for the regimens of vancomycin for 96 h and vancomycin followed by telavancin (P ≤ 0.04). No resistance was observed throughout the experiment. Against these MRSA and MSSA isolates with vancomycin MICs of 2 μg/ml, telavancin was comparable with vancomycin and its activity was unaffected by prior vancomycin exposure.

Update of the telavancin activity in vitro tested against a worldwide collection of Gram-positive clinical isolates (2013), when applying the revised susceptibility testing method

A revised broth microdilution susceptibility testing method for telavancin was approved by the Food and Drug Administration (FDA). Telavancin activity was assessed against Gram-positive pathogens collected worldwide (2013) using the revised method. A total of 12,346 isolates from 90 sites were included as part of the Telavancin International Surveillance Program for the Americas, Europe, and Asia-Pacific. Telavancin had MIC50 and MIC90 values of 0.03 and 0.06 μg/mL, respectively, against staphylococci, regardless of methicillin susceptibility, and inhibited all Staphylococcus aureus at ≤0.12 μg/mL (revised FDA breakpoint). Telavancin was 8-fold more active than daptomycin (MIC50/90, 0.25/0.5 μg/mL) and 16- to 32-fold more active than vancomycin (MIC50/90, 1/1 μg/mL) and linezolid (MIC50/90, 1/1 μg/mL) against methicillin-resistant S. aureus. All 692 vancomycin-susceptible Enterococcus faecalis were inhibited by telavancin (MIC50/90, 0.12/0.12 μg/mL) at ≤0.25 μg/mL (FDA breakpoint), except for 1 strain (MIC, 0.5 μg/mL). All Enterococcus faecium and E. faecalis with telavancin MIC values of ≥0.5 and ≥1 μg/mL, respectively, had a VanA phenotype. A comparison data analysis based on the MIC90 demonstrated that telavancin was at least 8-fold more potent than comparators against vancomycin-susceptible enterococci. Streptococci showed telavancin MIC50 values of ≤0.015 μg/mL, except for Streptococcus agalactiae (MIC50, 0.03 μg/mL). These in vitro results obtained by the recently approved susceptibility testing method establish a new benchmark of telavancin activity worldwide.

Periprosthetic joint infections: clinical and bench research

Prosthetic joint infection is a devastating complication with high morbidity and substantial cost. The incidence is low but probably underestimated. Despite a significant basic and clinical research in this field, many questions concerning the definition of prosthetic infection as well the diagnosis and the management of these infections remained unanswered. We review the current literature about the new diagnostic methods, the management and the prevention of prosthetic joint infections.