Proactive therapeutic monitoring of dalbavancin concentrations in the long-term management of chronic osteoarticular/periprosthetic joint infections.

Here, we describe the use of proactive therapeutic drug monitoring (TDM) to individualize the optimal timing of drug injections in 16 adult patients with chronic osteoarticular infections receiving a median of 7 injections of dalbavancin (up to 12 injections in 15 months). Dalbavancin injections were repeated at medians of 39-47 days, with infusion intervals ranging from 26 to 69 days. TDM can facilitates a precise, targeted use of dalbavancin for infections requiring prolonged treatments.

High prevalence of heteroresistance in Staphylococcus aureus is caused by a multitude of mutations in core genes.

Heteroresistance (HR) is an enigmatic phenotype where, in a main population of susceptible cells, small subpopulations of resistant cells exist. This is a cause for concern, as this small subpopulation is difficult to detect by standard antibiotic susceptibility tests, and upon antibiotic exposure the resistant subpopulation may increase in frequency and potentially lead to treatment complications or failure. Here, we determined the prevalence and mechanisms of HR for 40 clinical Staphylococcus aureus isolates, against 6 clinically important antibiotics: daptomycin, gentamicin, linezolid, oxacillin, teicoplanin, and vancomycin. High frequencies of HR were observed for gentamicin (69.2%), oxacillin (27%), daptomycin (25.6%), and teicoplanin (15.4%) while none of the isolates showed HR toward linezolid or vancomycin. Point mutations in various chromosomal core genes, including those involved in membrane and peptidoglycan/teichoic acid biosynthesis and transport, tRNA charging, menaquinone and chorismite biosynthesis and cyclic-di-AMP biosynthesis, were the mechanisms responsible for generating the resistant subpopulations. This finding is in contrast to gram-negative bacteria, where increased copy number of bona fide resistance genes via tandem gene amplification is the most prevalent mechanism. This difference can be explained by the observation that S. aureus has a low content of resistance genes and absence of the repeat sequences that allow tandem gene amplification of these genes as compared to gram-negative species.

Prevalence and molecular characteristics of heterogeneous vancomycin intermediate Staphylococcus aureus in a tertiary care center of northern China.

The use of glycopeptide medications may decline in line with the annual decline in methicillin-resistant Staphylococcus aureus (MRSA) detection rates in China. The rate of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA)detection may be impacted by this. However, there is currently a dearth of information on the incidence of hVISA in China. This study aims to analyze the recent epidemiology and molecular characteristics of hVISA strains in Beijing, China. A total of 175 non-duplicate MRSA strains from various infection sites were collected from a medical center between January 2018 and May 2023 and underwent molecular typing and susceptibility testing (Vitek2). Vancomycin and teicoplanin MICs were also evaluated by standard broth microdilution method and agar dilution method, respectively. Isolates growing on screening agar (BHIV4 and BHIT5, brain heart infusion agar containing 4 µg/ml vancomycin and 5 µg/ml teicoplanin, respectively) were characterized further by analysis of macro-Etest (MET) and population analysis profiling with area under the curve (PAP-AUC). The proportion of hVISA among MRSA isolates was 8.6 %. BHIT5 could select all hVISA strains while BHIV4 and MET only selected two hVISA strains. Compared with vancomycin- susceptible Staphylococcus aureus (VSSA), hVISA isolates were less susceptible to erythromycin and clindamycin. In addition, hVISA frequency was MIC-independent despite using different detection methods. In total, 11 types of STs, 28 types of spa typing, four types of SCCmec typing, and two types of agr typing were identified and the predominant type in both MRSA and hVISA isolates was ST239-t030-SCCmecIII-agr I. The analysis of biofilm formation, growth, and virulence genes in hVISA strains revealed sparse information. The dataset presented in this study provided the prevalence and molecular characteristics of hVISA in hospital settings and the combination of BHIT5 and PAP-AUC may identify hVISA efficiently. The result of genotyping suggested the genotype of hVISA was mainly consistent with that of local MRSA. Additional studies on the characteristics of hVISA strains were necessary.

Model-based dosing optimization and therapeutic drug monitoring practices of teicoplanin in patients with complicated or non-complicated methicillin-resistant staphylococcus aureus infection.

AIMS: This study aims to establish a population pharmacokinetic (PK) model of teicoplanin in Chinese adult patients to evaluate the dosing regimen in the label sheet and optimize it. METHODS: Nonlinear mixed-effects modelling was used to estimate PK parameters. Monte Carlo simulations were used to evaluate the attainment of various dosing regimens in achieving the target trough concentrations in patients with normal or decreased renal function. RESULTS: A total of 115 patients were enrolled in this retrospective study. Creatinine clearance (CrCL) and albumin (ALB) were identified as covariates on the clearance of teicoplanin. For the treatment of non-complicated methicillin-resistant Staphylococcus aureus (MRSA) infections in patients with normal renal function and serum ALB concentration, the recommended dosing regimen was 600 mg q12h with five administrations as the loading dose followed by 600 mg qd as the maintenance dose; for the treatment of serious and/or complicated MRSA infections, the recommended dosing regimen was 800 mg q12h with five administrations as the loading dose followed by 800 mg qd as the maintenance dose. It is worth noting that both the loading and maintenance doses ought to be modified based on the patient's renal function and serum ALB concentration. In addition, trough concentrations of teicoplanin were significantly increased every other week. CONCLUSIONS: Both loading dosing and maintenance dosing regimens were recommended to be adjusted according to patient's renal function and serum ALB concentration. In addition, it is necessary to perform follow-up therapeutic drug monitoring of teicoplanin at least once every week.

Implementation and validation of a Bayesian method for accurately forecasting duration of optimal pharmacodynamic target attainment with dalbavancin during long-term use for subacute and chronic staphylococcal infections.

Dalbavancin is increasingly being used for long-term treatment of subacute and chronic staphylococcal infections. In this study, a new Bayesian model was implemented and validated using MwPharm software for accurately forecasting the duration of pharmacodynamic target attainment above the efficacy thresholds of 4.02 mg/L or 8.04 mg/L against staphylococci. Forecasting accuracy improved substantially with the a posteriori approach compared with the a priori approach, particularly when two measured concentrations were used. This strategy may help clinicians to estimate the duration of optimal exposure with dalbavancin in the context of long-term treatment.

Molecular and Clinical Features of Heterogeneous Vancomycin-Intermediate Staphylococcus aureus in Tertiary Care Hospitals in South India.

Objectives: This study aimed to detect heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) among methicillin-resistant S. aureus (MRSA) isolated from healthcare-associated infections and identify staphylococcal cassette chromosome mec (SCCmec) types. Methods: This study was conducted from February 2019 to March 2020 and included patients admitted in 4 tertiary care hospitals in Karnataka, India. Isolation and identification of MRSA were done using standard bacteriological methods. Antimicrobial susceptibility testing was done using Kirby-Bauer disc diffusion; macrolide-lincosamide-streptogramin B phenotypes were identified using the D test. The minimum inhibitory concentration (MIC) of vancomycin was determined using agar dilution. hVISA were confirmed by the modified population analysis profile-area under the curve test. SCCmec types and the Panton-Valentine leukocidin (pvl) gene were detected using multiplex polymerase chain reaction. Results: Of 220 MRSA stains, 14 (6.4%) were hVISA. None of the MRSA isolates was vancomycin-intermediate or -resistant and all hVISA were susceptible to linezolid and teicoplanin. The macrolide-streptogramin B phenotype was present in 42.9% of hVISA; 92.9% of the hVISA strains had vancomycin MIC in the range of 1-2 µg/mL. Majority of the hVISA and vancomycin-susceptible MRSA were isolated from patients with skin and soft tissue infections. SCCmec III and IV were present in 50% and 35.7% of hVISA, respectively; 14.3% of the hVISA harboured SCCmec V. Conclusion: The prevalence rate of hVISA among MRSA was 6.4%. Therefore, MRSA strains should be tested for hVISA before starting vancomycin treatment. None of the isolates was vancomycin-intermediate or -resistant and all the hVISA strains were susceptible to linezolid and teicoplanin. The majority of the hVISA were isolated from patients with skin and soft tissue infections and harboured SCCmec III and IV.

Successful Outpatient Treatment of Severe Diabetic-Foot Myositis and Osteomyelitis Caused by Extensively Drug-Resistant Enterococcus faecalis with Teicoplanin plus Rifampicin: A Case Report.

BACKGROUND Foot ulcers are high-morbidity and debilitating complications of diabetes mellitus, and carry significantly increased rates of associated major amputations. They contribute to significantly worse quality of life. Osteomyelitis is a frequent complication of diabetic foot ulcers, since bacteria can contiguously spread from soft tissues to the bone, involving the cortex first and then the bone marrow. Unfortunately, clinically unsuspected osteomyelitis is frequent in persisting diabetic foot ulcers. It is associated with limb amputations and increased mortality. CASE REPORT We describe a 76-year-old man with long-standing insulin-treated type 2 diabetes, who experienced extensively drug-resistant Enterococcus faecalis diabetic foot myositis and osteomyelitis associated with sepsis. He was successfully treated with surgical debridement combined with the administration of teicoplanin plus rifampicin in the outpatient setting, completing, in total, a twelve-week course of antibiotic therapy. CONCLUSIONS Clinically unsuspected osteomyelitis in patients with persisting diabetic foot ulcers has been associated with infections from highly resistant bacteria. Early and accurate diagnosis of diabetic foot osteomyelitis, as well as proper therapeutic approach (antimicrobial and surgical), is of great importance to reduce the risk of minor and major amputations, septic shock leading to multiple organ failure, and overall mortality.

Oral teicoplanin administration suppresses recurrence of Clostridioides difficile infection: Proof of concept.

OBJECTIVES: Teicoplanin is a potential antimicrobial candidate for Clostridioides difficile infection (CDI) treatment. However, the therapeutic potential of teicoplanin against severe CDI has not been clinically proven. In the present study, we investigated the efficacy of oral teicoplanin administration against severe CDI and the recurrence of severe CDI after teicoplanin treatment in a mouse model. METHODS: A lethal CDI mouse model was established by colonizing the mice with C. difficile ATCC® 43255; they were orally administered teicoplanin (128 mg/kg/d) or vancomycin (160 mg/kg/d) for 10 d, 24 h after C. difficile spore challenge, and physiological and biological responses were monitored for 20 d after the initial antibiotic treatment. We also performed the in vitro time-kill assay and determined minimum inhibitory concentration (MIC), post-antibiotic effect, and toxin production with antibiotic exposure. RESULTS: The therapeutic response (survival rates, body weight change, clinical sickness score grading, C. difficile load, and toxin titer in feces) of oral teicoplanin administration was comparable to that of oral vancomycin administration in the lethal CDI mouse model. Moreover, teicoplanin treatment suppressed the re-onset of diarrhea and re-increase in toxin titer 10 d after treatment compared with that by vancomycin treatment. In in vitro experiments, teicoplanin exhibited time-dependent antibacterial activity and possessed lower MIC and longer post-antibiotic effect than vancomycin against C. difficile. C. difficile toxin production was numerically lower with teicoplanin exposure than with vancomycin exposure. CONCLUSIONS: The results obtained from the present basic experiments could suggest that teicoplanin is a potential antibiotic for the treatment of severe CDI with recurrence-prevention activity.

Efficacy of boric acid used to treat experimental vascular graft infection by methicillin-resistant Staphylococcus aureus.

INTRODUCTION: We aimed to investigate the efficacy of local boric acid (BA) and teicoplanin in prosthetic vascular graft infection (PVGI) caused by methicillin-resistant Staphylococcus aureus (MRSA) in a rat model. METHODOLOGY: Fourty rats were divided into five groups. Group 1 received no treatments (control group); group 2 was uncontaminated polytetrafluoroethylene (PTFE) graft group; group 3 was untreated and the PTFE graft was contaminated with 2×107 CFU/mL MRSA; group 4 received local BA (8 mg/kg) and was contaminated with with 2×107 CFU/mL MRSA; group 5 received local BA (8 mg/kg) and intraperitoneal teikoplanin (10 mg/kg), and was contaminated with 2×107 CFU/mL MRSA; On the 3rd day, grafts and serums were removed for microbiological, histological and serological tests. RESULTS: The amounts of culture growth in groups 4 and 5 were significantly lower compared to group 3 (p < 0.001). TNF-α was significantly higher in Group 3 than the other groups (p = 0.001). There was no significant difference between the groups in serum IL-1 levels (p = 0.138). Monocyte chemotactic protein-1 (MCP-1) was not significantly different between groups 3, 4, and 5, but it was significantly higher than groups 1 and 2 (p < 0.001). The severity of inflammation was significantly higher in group 3 than the other groups, and fibroblastic proliferation, granulation tissue and collagen synthesis were significantly lower (p < 0.05). CONCLUSIONS: Our study showed that local BA and combined teicoplanin treatment is effective in preventing PVGI.

Characteristics of Gram-positive cocci infection and the therapeutic effect after liver transplantation. / è‚ç§»æ¤æœ¯åŽé©å °æ°é˜³æ€§çƒèŒçš„æ„ŸæŸ“ç‰¹ç‚¹åŠé˜²æ²»æ•ˆæžœ.

OBJECTIVES: Gram-positive cocci is the main pathogen responsible for early infection after liver transplantation (LT), posing a huge threat to the prognosis of liver transplant recipients. This study aims to analyze the distribution and drug resistance of Gram-positive cocci, the risk factors for infections and efficacy of antibiotics within 2 months after LT, and to guide the prevention and treatment of these infections. METHODS: In this study, data of pathogenic bacteria distribution, drug resistance and therapeutic efficacy were collected from 39 Gram-positive cocci infections among 256 patients who received liver transplantation from donation after citizens' death in the Third Xiangya Hospital of Central South University from January 2019 to July 2022, and risk factors for Gram-positive cocci infection were analyzed. RESULTS: Enterococcus faecium was the dominant pathogenic bacteria (33/51, 64.7%), followed by Enterococcus faecalis (11/51, 21.6%). The most common sites of infection were abdominal cavity/biliary tract (13/256, 5.1%) and urinary tract (10/256, 3.9%). Fifty (98%) of the 51 Gram-positive cocci infections occurred within 1 month after LT. The most sensitive drugs to Gram-positive cocci were teicoplanin, tigecycline, linezolid and vancomycin. Vancomycin was not used in all patients, considering its nephrotoxicity. Vancomycin was not administered to all patients in view of its nephrotoxicity.There was no significant difference between the efficacy of daptomycin and teicoplanin in the prevention of cocci infection (P>0.05). Univariate analysis indicated that preoperative Model for End-Stage Liver Disease (MELD) score >25 (P=0.005), intraoperative red blood cell infusion ≥12 U (P=0.013) and exposure to more than 2 intravenous antibiotics post-LT (P=0.003) were related to Gram-positive cocci infections. Multivariate logistic regression analysis revealed that preoperative MELD score >25 (OR=2.378, 95% CI 1.124 to 5.032, P=0.024) and intraoperative red blood cell transfusion ≥ 12 U (OR=2.757, 95% CI 1.227 to 6.195, P=0.014) were independent risk factors for Gram-positive cocci infections after LT. Postoperative Gram-positive cocci infections were reduced in LT recipients exposing to more than two intravenous antibiotics post-LT (OR=0.269, 95% CI 0.121 to 0.598, P=0.001). CONCLUSIONS: Gram-positive cocci infections occurring early after liver transplantation were dominated by Enterococcus faecalis infections at the abdominal/biliary tract and urinary tract. Teicoplanin, tigecycline and linezolid were anti-cocci sensitive drugs. Daptomycin and teicoplanin were equally effective in preventing cocci infections due to Gram-positive cocci. Patients with high preoperative MELD score and massive intraoperative red blood cell transfusion were more likely to suffer Gram-positive cocci infection after surgery. Postoperative Gram-positive cocci infections were reduced in recipients exposing to more than two intravenous antibiotics post-LT.

Expert Opinion on Dose Regimen and Therapeutic Drug Monitoring for Long-Term Use of Dalbavancin: Expert Review Panel.

BACKGROUND: Dalbavancin is a lipoglycopeptide with a long elimination half-life and is currently licensed for the treatment of acute bacterial skin and skin structure infections in adults. Dalbavancin's potential in treating off-label complex Gram-positive infections is promising and real-world experience in treating such infections is growing. However, clear guidance on extended dosing regimens is lacking. OBJECTIVES: This study aimed to provide clear expert opinion based on recent pharmacokinetic literature and expert and real-world experience in infection areas that require > 2 weeks of treatment. METHODS: A single face-to-face meeting was held in September 2022 to collate expert opinion and present safety data of dalbavancin use in these clinical indications. A survey was completed by all authors on their individual experience with dalbavancin, which highlighted the heterogeneity in the regimens that were used. RESULTS: After review of the survey data and recent literature, this study presents expert panel proposals that accommodate different healthcare settings and resource availability, and centre around the length of treatment duration including up to or exceeding 6 weeks. To achieve adequate dalbavancin concentrations for up to 6 weeks, 3000 mg of dalbavancin should be given over 4 weeks for the agreed complex infections requiring > 2 weeks of treatment. Therapeutic drug monitoring (TDM) is advised for longer treatment durations and in cases of renal failure. Specific dosing recommendations for other special populations require further investigation. CONCLUSIONS: These proposals based on expert opinion have been defined to encourage best practice with dalbavancin, to optimise its administration beyond the current approved licenced dose across different healthcare settings.

A HPLC-DAD method to facilitate large-scale therapeutic drug monitoring of dalbavancin.

Dalbavancin, a long-acting lipoglycopeptide antibiotic targeting susceptible Gram-positive bacteria, is WHO critically important antibiotic, increasingly used in critical situations such as osteoarticular infections. To ensure its effectiveness and its safety, the therapeutic drug monitoring (TDM) of dalbavancin is strongly recommended. In the absence of an available minimum inhibitory concentration (MIC), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends a breakpoint of 0.125 mg/L for Staphylococcus aureus, corresponding to a trough target concentration of 25 mg/L. Nowadays, the TDM is usually performed using a high-performance liquid chromatography (HPLC) method coupled with a tandem mass spectrometry. However, this expensive and specialized equipment and reagents may be difficult to acquire for non-specialized laboratories. The use of HPLC coupled with diode array detector (DAD) facilitates TDM with a lower cost, while preserving the reliability of the results. Our aim was to provide a sensitive and specific method, relying on HPLC-DAD for extending the TDM of dalbavancin beyond non-specialized labs, therefore maximizing its efficiency and Benefit/risk ratio. Our method complied with the European Medicines Agency guidelines of bioanalytical validation. Irrespective of the concentrations of dalbavancin, the coefficient of variation < 10% confirmed the reliability of this analytical method, with a calibration curve ranging from 5 to 100 mg/L. No interferences nor carryover was observed. Our HPLC-DAD method, combined with a simple extraction, provides a widely usable, inexpensive and easy-to-implement new asset for the TDM of Dalbavancin.

Accuracy of Therapeutic Drug Monitoring of Teicoplanin at the Onset of Febrile Neutropenia.

Background and Objectives: Teicoplanin (TEIC) is an effective drug for patients with febrile neutropenia (FN); however, it has been reported that these patients may have increased TEIC clearance compared with patients who do not have FN. The purpose of this study was to study therapeutic drug monitoring in patients with FN when the TEIC dosing design was based on the population mean method. Materials and Methods: Thirty-nine FN patients with hematological malignancy were included in the study. To calculate the predicted blood concentration of TEIC, we used the two population pharmacokinetic (population PK) parameters (parameters 1 and 2) reported by Nakayama et al. and parameter 3, which is a modification of the population PK of Nakayama et al. We calculated the mean prediction error (ME), an indicator of prediction bias, and the mean absolute prediction error (MAE), an indicator of accuracy. Furthermore, the percentage of predicted TEIC blood concentration within 25% and 50% of the measured TEIC blood concentration was calculated. Results: The ME values were -0.54, -0.25, and -0.30 and the MAE values were 2.29, 2.19, and 2.22 for parameters 1, 2, and 3, respectively. For all of the three parameters, the ME values were calculated as minus values, and the predicted concentrations tended to be biased toward smaller values relative to the measured concentrations. Patients with serum creatinine (Scr) < 0.6 mg/dL and neutrophil counts < 100/µL had greater ME and MAE values and a smaller percentage of predicted TEIC blood concentration within 25% of measured TEIC blood concentrations compared with other patients. Conclusions: In patients with FN, the accuracy of predicting TEIC blood concentrations was good, with no significant differences between each parameter. However, patients with a Scr < 0.6 mg/dL and a neutrophil count < 100/µL showed slightly inferior prediction accuracy.

Cost analysis of disease including treatment with dalbavancin in a Spanish hospital: ECODAL ANALYSIS.

INTRODUCTION AND AIM: Dalbavancin is an antibiotic with activity against gram-positive bacteria that allows early discharge of patients requiring intravenous therapy. Outpatient treatment helps offset hospitalisation costs associated with standard intravenous treatment. Our objective was to assess the cost of disease management, including treatment with dalbavancin, in a Spanish hospital for 1 year, and the hypothetical costs associated with treatment with other therapeutic alternatives to dalbavancin. METHODS: A single-centre, observational, retrospective post-hoc analysis was conducted based on electronic medical records analysing all patients who received dalbavancin treatment throughout 1 year; cost analysis was performed for the whole process. In addition, three scenarios designed on the basis of real clinical practice by clinical experts were hypothesised: (i) individual therapeutic alternative to dalbavancin, (ii) all patients treated with daptomycin, and (iii) all days of dalbavancin as outpatient treatment transformed into hospital stay. Costs were obtained from the hospital. RESULTS: Thirty-four patients were treated with dalbavancin; their mean age was 57.9 years, and 70.6% were men. The main reasons for dalbavancin use were outpatient management (61.7%, n = 21) and ensuring treatment adherence (26.5%, n = 9). The main indications were: osteoarticular infection (32.4%) and infective endocarditis (29.4%). One-half (50%) of the infections were due to Staphylococcus aureus (23.5% were methicillin resistant). All patients achieved clinical resolution, and no costs associated with dalbavancin-associated adverse events or re-admissions were reported. The mean total cost of treatment was 22,738€ per patient, with the greatest expenditures in interventions (8,413€) and hospital stay (6,885€). The mean cost of dalbavancin treatment was 3,936€; without dalbavancin, this cost could have been increased to 3,324-11,038€ depending on the scenario, mainly due to hospital stays. MAIN LIMITATION: Limited sample size obtained from a single centre. CONCLUSION: The economic impact of the management of these infections is high. The cost of dalbavancin is offset by the decreased length of stay.

Dalbavancin Boosts the Ability of Neutrophils to Fight Methicillin-Resistant Staphylococcus aureus.

Polymorphonuclear leukocytes (PMNs) are the most important cell type involved in the early nonspecific host response to bacterial pathogens. Staphylococcus aureus has evolved mechanisms to evade immune responses that contribute to its persistence in PMNs, and acquired resistance to several antimicrobials. Additionally, methicillin-resistant S. aureus (MRSA) is one of the most common causes of acute bacterial skin and skin-structure infections (ABSSSIs). Dalbavancin (DBV), a lipoglycopeptide, is indicated for the treatment of ABSSSIs, and has a broad spectrum of action against most microorganisms. Here, we sought to determine the effect of DBV on the neutrophil killing of MRSA and its potential immunomodulating activity. Our results revealed that DBV boosts MRSA killing by acting on both bacteria and PMNs. DBV pre-treatment of PMNs did not change the respiratory burst or degranulation, while an increased trend in neutrophil extracellular traps-associated elastase and in the production of TNFα and CXCL8 was revealed. In parallel, DBV caused a delay in the apoptosis of MRSA-infected neutrophils. In conclusion, we demonstrated a cooperative effect between the antimicrobial properties of PMNs and DBV, thus owing to their immunomodulatory activity. In the choice of the treatment management of serious S. aureus infections, DBV should be considered as an outstanding option since it reinforces PMNs pathogen clearance capability by exerting its effect directly, not only on MRSA but also on neutrophils.