Comparison of the pharmacokinetics, safety and tolerability of daptomycin in healthy adult volunteers following intravenous administration by 30 min infusion or 2 min injection

Phenotypic and genetic characterization of daptomycin non-susceptible Staphylococcus aureus strains selected by adaptive laboratory evolution

Background

Daptomycin non-susceptible Staphylococcus aureus (DNS) strains pose a serious clinical threat, yet their characteristics remain poorly understood.

Methods

DNS derivatives were generated by exposing S. aureus strains to subinhibitory concentrations of daptomycin. Competition experiment and growth kinetics experiment were used to observe the growth of bacteria. Galleria mellonella larvae and mouse skin abscess models were used to observe the virulence of bacteria. Transmission electron microscopy (TEM), cytochrome C experiment and biofilm formation experiment were used to observe the drug resistance phenotype. And homologous recombination was used to study the role of mutations.

Results

Phenotypic profiling of DNS strains revealed impaired growth, increased cell wall thickness, enhanced biofilm formation, reduced negative surface charge, and attenuated virulence compared to their wild-type strains. Whole genome sequencing identified mutations in mprF, cls2, and saeR in DNS strains. Allelic replacement experiments validated the roles of MprF L341F and Cls2 F60S substitutions in augmenting daptomycin non-susceptibility in Newman. Deletion of saeR in the NewmanMprFL341F strain and complementation of saeR in the Newman-DNS strain did not directly alter daptomycin susceptibility. However, the deletion of saeR was found to enhance competitive fitness under daptomycin pressure.

Conclusion

This work validates adaptive laboratory evolution (ALE) for modeling clinical DNS strains and uncovers contributions of mprF, cls2, and saeR mutations to the adaptation and resistance mechanisms of S. aureus against daptomycin. These findings enrich our understanding of how S. aureus acquired resistance to daptomycin, thus paving the way for the development of more effective treatment strategies and offering potential molecular markers for resistance surveillance.

Daptomycin Pharmacokinetics in Blood and Wound Fluid in Critical Ill Patients with Left Ventricle Assist Devices

Daptomycin is a cyclic lipopeptide antibiotic with bactericidal effects against multidrug-resistant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). For critically ill patients, especially in the presence of implants, daptomycin is an important therapeutic option. Left ventricle assist devices (LVADs) can be utilized for intensive care patients with end-stage heart failure as a bridge to transplant. We conducted a single-center prospective trial with critically ill adults with LVAD who received prophylactic anti-infective therapy with daptomycin. Our study aimed to evaluate the pharmacokinetics of daptomycin in the blood serum and wound fluids after LVAD implantation. Daptomycin concentration were assessed over three days using high-performance liquid chromatography (HPLC). We detected a high correlation between blood serum and wound fluid daptomycin concentration at 12 h (IC95%: 0.64 to 0.95; r = 0.86; p < 0.001) and 24 h (IC95%: -0.38 to 0.92; r = 0.76; p < 0.001) after antibiotic administration. Our pilot clinical study provides new insights into the pharmacokinetics of daptomycin from the blood into wound fluids of critically ill patients with LVADs.

Physiologically based pharmacokinetic modeling of daptomycin dose optimization in pediatric patients with renal impairment

Background and Objective: Daptomycin is used to treat Gram-positive infections in adults and children and its dosing varies among different age groups. We focused on the pharmacokinetics of daptomycin in children with renal impairment, which has not been evaluated.

Methods: A physiologically based pharmacokinetic (PBPK) model of daptomycin was established and validated to simulate its disposition in healthy populations and adults with renal impairment, along with a daptomycin exposure simulated in pediatric patients with renal impairment.

Results: The simulated PBPK modeling results for various regimens of intravenously administered daptomycin were consistent with observed data according to the fold error below the threshold of 2. The Cmax and AUC of daptomycin did not differ significantly between children with mild-to-moderate renal impairment and healthy children. The AUC increased by an average of 1.55-fold and 1.85-fold in severe renal impairment and end-stage renal disease, respectively. The changes were more significant in younger children and could reach a more than 2-fold change. This scenario necessitates further daptomycin dose adjustments.

Conclusion: Dose adjustments take into account the efficacy and safety of the drug; however, the steady-state Cmin of daptomycin may be above 24.3 mg/L in a few instances. We recommend monitoring creatine phosphokinase more than once a week when using daptomycin in children with renal impairment.

Clinical Pharmacokinetics of Daptomycin

Due to the low level of resistance observed with daptomycin, this antibiotic has an important place in the treatment of severe Gram-positive infections. It is the first-in-class of the group of calcium-dependent, membrane-binding lipopeptides, and is a cyclic peptide constituted of 13 amino acids and an n-decanoyl fatty acid chain. The antibacterial action of daptomycin requires its complexation with calcium. Daptomycin is not absorbed from the gastrointestinal tract and needs to be administered parenterally. The distribution of daptomycin is limited (volume of distribution of 0.1 L/kg in healthy volunteers) due to its negative charge at physiological pH and its high binding to plasma proteins (about 90%). Its elimination is mainly renal, with about 50% of the dose excreted unchanged in the urine, justifying dosage adjustment for patients with renal insufficiency. The pharmacokinetics of daptomycin are altered under certain pathophysiological conditions, resulting in high interindividual variability. As a result, therapeutic drug monitoring of daptomycin may be of interest for certain patients, such as intensive care unit patients, patients with renal or hepatic insufficiency, dialysis patients, obese patients, or children. A target for the ratio of the area under the curve to the minimum inhibitory concentration > 666 is usually recommended for clinical efficacy, whereas in order to limit the risk of undesirable muscular effects the residual concentration should not exceed 24.3 mg/L.

High-Dose Daptomycin Is Well Tolerated via 2-Minute IV Push Administration

Background

The purpose of this study was to evaluate the safety of administering high-dose daptomycin (HDD; > 6 mg/kg actual body weight) as a 2-minute intravenous (IV) push (IVP) compared to traditional 30-minute IV piggyback (IVPB) infusion.

Methods

Retrospective cohort study comparing patients receiving HDD as an IVP or IVPB infusion. The primary outcome was the proportion of patients with a documented infusion-related reaction (IRR) to daptomycin.

Results

Three hundred patients were included in the final analysis, 200 patients received IVP, and 100 patients received IVPB representing a total of 1697 administrations. Median (IQR) daptomycin dose was IVP 700 mg (550-900) and IVPB 700 mg (600-900), with mg/kg doses of 8.2 (7.9-10) and 8.3 (8-10), respectively. After adjudication, IRR occurred in 1% of subjects in each treatment group.

Conclusions

This study provides data in more than 1100 administrations of HDD administered via IVP. Infusion-related reactions were documented in 1% of patients regardless of infusion method, suggesting comparable safety to traditional infusion methods. This practice may be useful during fluid shortage and in the outpatient setting.

Comparison of the Drug-Drug Interaction Potential of Daptomycin in Combination with Rifampin in Healthy Adult Volunteers

We evaluated the effects of rifampin coadministration and MDR1 single nucleotide polymorphisms on the disposition of daptomycin in twelve healthy adults. There were no significant changes from baseline in the clearance (0.53 versus 0.55 liters/h, P = 1.00), volume of distribution (7.0 versus 7.2 liter, P = 0.62), or half-life (9.7 versus 9.6 h, P = 0.89) of daptomycin after exposure to rifampin. The tested MDR1 polymorphisms were not associated with significant differences in daptomycin disposition.

Pharmacokinetic/pharmacodynamic parameters for treatment optimization of infection due to antibiotic resistant bacteria: a summary for practical purposes in children and adults

In the last years, there has been a tremendous increase in the incidence of bacterial infections due to resistant strains, especially multi-drug resistant Gram-negative bacilli. In Europe, a north to south and a west to east gradient was noticed, with more than one third of the K. pneumonia isolates being resistant to carbapenems in few countries. New antibiotics are lacking and, as a consequence, pharmacokinetic/pharmacodynamic parameters, normalized to pathogen minimal inhibitory concentration, are used with increased frequency to treat infections due to difficult-to-treat pathogens. These parameters are available at least for the adult population, but sparse in many different publications. This review wants to provide a comprehensive and 'easy to read' text for everyday practice, briefly summarizing the presently available knowledge on pharmacokinetic/pharmacodynamic parameters (normalized for minimal inhibitory concentration values) of different class drugs, that can be applied for an effective antibacterial treatment infections due to antibiotic-resistant pathogens.

Safety and efficacy of daptomycin in outpatient parenteral antimicrobial therapy: a prospective and multicenter cohort study (DAPTODOM trial)

BACKGROUND

Daptomycin is an optimal choice for outpatient parenteral antibiotic therapy (OPAT) because of its safety, once-daily administration and its activity against Gram-positive bacteria. Although daptomycin is increasingly being used in OPAT, limited information about its safety in this scenario is available.

METHODS

We performed a prospective multicentre pilot study to evaluate the safety of daptomycin in outpatients with proved or suspected Gram-positive infections (DAPTODOM). The primary objective was to evaluate the safety and the secondary objective to evaluate the efficacy in OPAT. We also looked at the development of daptomycin resistance in those cases with microbiological failure.

RESULTS

We included 54 patients from 12 Spanish hospitals, 67% male with a mean age of 67.1 years. Most patients (87%) had chronic underlying diseases. The main reason for inclusion was skin and soft-tissue infections in 52%, followed by bacteremia or endocarditis in 34%. Staphylococcus aureus accounted for 44% of the isolates (24% were methicillin-resistant), coagulase-negative staphylococci 15% and enterococci 7%. Two patients (4%) had to be readmitted because of complications; only one patient had an adverse effect related to daptomycin (increase in serum creatine kinase levels), which disappeared after discontinuation (2%). At the end of follow-up, 96% of patients had good outcome and only 4% of patients did not have a clinical or microbiological cure. The use of a 2-minute bolus in 18 cases was not associated with adverse effects.

CONCLUSIONS

Daptomycin was safe and efficacious in outpatients with Gram-positive bacterial infections and can be administered in 2-minute bolus infusion.

Daptomycin: an evidence-based review of its role in the treatment of Gram-positive infections

Infections caused by Gram-positive pathogens remain a major public health burden and are associated with high morbidity and mortality. Increasing rates of infection with Gram-positive bacteria and the emergence of resistance to commonly used antibiotics have led to the need for novel antibiotics. Daptomycin, a cyclic lipopeptide with rapid bactericidal activity against a wide range of Gram-positive bacteria including methicillin-resistant Staphylococcus aureus, has been shown to be effective and has a good safety profile for the approved indications of complicated skin and soft tissue infections (4 mg/kg/day), right-sided infective endocarditis caused by S. aureus, and bacteremia associated with complicated skin and soft tissue infections or right-sided infective endocarditis (6 mg/kg/day). Based on its pharmacokinetic profile and concentration-dependent bactericidal activity, high-dose (>6 mg/kg/day) daptomycin is considered an important treatment option in the management of various difficult-to-treat Gram-positive infections. Although daptomycin resistance has been documented, it remains uncommon despite the increasing use of daptomycin. To enhance activity and to minimize resistance, daptomycin in combination with other antibiotics has also been explored and found to be beneficial in certain severe infections. The availability of daptomycin via a 2-minute intravenous bolus facilitates its outpatient administration, providing an opportunity to reduce risk of health care-associated infections, improve patient satisfaction, and minimize health care costs. Daptomycin, not currently approved for use in the pediatric population, has been shown to be widely used for treating Gram-positive infections in children.

Outpatient parenteral antimicrobial therapy and antimicrobial stewardship: challenges and checklists

Outpatient parenteral antimicrobial therapy (OPAT) has become, for many countries, an established form of healthcare delivery. At the same time, there have been calls to ensure the prudent use of the existing antimicrobial armamentarium. For OPAT, this presents a dilemma. On one hand, stewardship principles look for the most effective agent with minimal collateral effects. In OPAT, whilst the aims of the service are similar, convenience of dosing to optimize early hospital discharge or admission avoidance may take precedence over an agent's spectrum of activity. This brief article aims to highlight the importance and explore the challenges of antimicrobial stewardship in the context of OPAT. Within the UK, the safe and effective use of antimicrobials is modelled around the IDSA/Society for Healthcare Epidemiology of America stewardship practice guidelines with local customization where appropriate. Current UK stewardship practice principles were compared with published good practice recommendations for OPAT to identify how OPAT could support the broader antimicrobial stewardship agenda. It is essential that antimicrobial stewardship teams should understand the challenges faced in the non-inpatient setting and the potential benefits/lower risks associated with avoided admission or shortened hospital stay in this population. Within its limitations, OPAT should practise stewardship principles, including optimization of intravenous to oral switch and the reporting of outcomes, healthcare-associated infections and re-admission rates. OPAT should report to the antimicrobial stewardship team. Ideally the OPAT team should be formally represented within the stewardship framework. A checklist has been proposed to aid OPAT services in ensuring they meet their stewardship agenda.

Infusion-related reaction following daptomycin two-minute rapid intravenous administration

BACKGROUND

Erythroderma, or red man's syndrome, is a common infusion-related reaction following vancomycin administration. Erythroderma following daptomycin rapid infusion has not been documented.

OBJECTIVE

To report a case of erythroderma following daptomycin 2-minute intravenous (IV) injection.

CASE REPORT

A review of published literature suggests that this is the first published case of a flushing (nonallergic) reaction resulting from a 2-minute IV injection of daptomycin that is not present with standard IV infusion. A 69-year-old woman following right knee reconstructive surgery presented with right knee joint swelling, purulent discharge, and fever. Subsequently, she was diagnosed with a presumed postsurgical infection and was initiated on vancomycin therapy. Following removal of the infected hardware, the patient was discharged and continued outpatient vancomycin therapy. The patient's renal function began to decline and therapy was discontinued. Daptomycin 6 mg/kg every 48 hours was initiated via 2-minute IV push. On the initial dose, approximately 2 hours post IV infusion, the patient began to notice redness and a warm sensation on her face, neck, and upper part of the chest. Diphenhydramine 25 mg provided limited immediate relief, but all symptoms subsided within 3 to 4 hours. The patient received her next dose 48 hours later over a 40-minute IV infusion with no adverse effects. Subsequent infusions continued at the same dose over 30 minutes for 4 weeks with no further adverse effects.

CONCLUSION

A 2-minute intravenous injection of daptomycin in this patient yielded a reaction that was not present on rechallenge with standard, extended infusion.

Evaluation of the safety, tolerability, and pharmacokinetics of a single bolus injection of daptomycin in healthy Japanese subjects

This was a phase I double-blind, randomized, placebo-controlled, 2-period, single-dose, crossover study in healthy Japanese subjects to evaluate the safety, tolerability, and pharmacokinetics of a single bolus injection of daptomycin. Twenty healthy subjects were randomized; 16 received a single intravenous (IV) administration of 6 mg/kg of daptomycin and 4 received a single intravenous administration of placebo (0.9% sodium chloride) by either bolus injection (10 s) or infusion (30 min) following an overnight fast in Periods 1 or 2. There was a minimum 5-day washout period from the administration in Period 1 to the administration in Period 2. Administration of a single bolus injection of daptomycin 6 mg/kg was generally well tolerated. The geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for AUC0-∞, AUC0-24 h, Cmax, and C24 h of daptomycin in plasma following bolus injection over 10 s relative to IV infusion over 30 min were 1.01 (1.00, 1.03), 1.02 (1.00, 1.03), 1.50 (1.41, 1.60) and 1.05 (1.02, 1.08), respectively. Because no existing studies of this nature were available, Cmax following daptomycin 6 mg/kg/10 s multiple-dose bolus injections was simulated. It was estimated at 178 μg/mL (upper limit) and was expected to be equal to or less than the confirmed Cmax in Japanese or non-Japanese healthy subjects following single- or multiple-dose IV infusion over 30 min. From the results of this study, daptomycin multiple-dose bolus injections over 10 s are expected well tolerated and to have similar Cmax values as IV infusion over 30 min, thus offering potential clinical benefit.

TRIAL REGISTRATION

Because this was a phase I trial in healthy subjects, the trial was not registered.

Public reporting improves antibiotic prescribing for upper respiratory tract infections in primary care: a matched-pair cluster-randomized trial in China

BACKGROUND

Inappropriate use and overuse of antibiotics is a serious concern in the treatment of upper respiratory tract infections (URTIs), especially in developing countries. In recent decades, information disclosure and public reporting (PR) has become an instrument for encouraging good practice in healthcare. This study evaluated the impact of PR on antibiotic prescribing for URTIs in a sample of primary care institutions in China.

METHODS

A matched-pair cluster-randomized trial was undertaken in QJ city, with 20 primary care institutions participating in the trial. Participating institutions were matched into pairs before being randomly assigned into a control and an intervention group. Prescription statistics were disclosed to patients, health authorities, and health workers monthly within the intervention group, starting from October 2013. Outpatient prescriptions for URTIs were collected from both groups before (1st March to 31st May, 2013) and after the intervention (1st March to 31st May, 2014). A total of 34,815 URTI prescriptions were included in a difference-in-difference analysis using multivariate linear or logistic regression models, controlling for patient attributes as well as institutional characteristics.

RESULTS

Overall, 90% URTI prescriptions required antibiotics and 21% required combined use of antibiotics. More than 77% of URTI prescriptions required intravenous (IV) injection or infusion of drugs. PR resulted in a 9 percentage point (95% CI -17 to -1) reduction in the use of oral antibiotics (adjusted RR = 39%, P = 0.027), while the use of injectable antibiotics remained unchanged. PR led to a 7 percentage point reduction (95% CI -14 to 0; adjusted RR = 36%) in combined use of antibiotics (P = 0.049), which was largely driven by a significant reduction in male patients (-7.5%, 95% CI -14 to -1, P = 0.03). The intervention had little impact on the use of IV injections or infusions, or the total prescription expenditure.

CONCLUSIONS

The results suggest that PR could improve prescribing practices in terms of reducing oral antibiotics and combined use of antibiotics; however, the impacts were limited. We suggest that PR would probably be enhanced by provider payment reform, management and training for providers, and health education for patients.

Daptomycin dosing strategies in patients receiving thrice-weekly intermittent hemodialysis

OBJECTIVE

To determine the optimal dosing regimen of daptomycin in patients receiving thrice-weekly hemodialysis.

DATA SOURCES

Literature was accessed via PubMed using the terms daptomycin and hemodialysis through July 2013. Reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION

English language articles meeting the search criteria were evaluated. Studies were included if they addressed either thrice-weekly or intradialytic daptomycin administration.

DATA SYNTHESIS

Daptomycin is approved for the treatment of bloodstream infections due to methicillin-resistant Staphylococcus aureus and other Gram-positive organisms. Rapid bactericidal activity and limited potential for drug interactions make daptomycin an attractive agent. However, the daptomycin prescribing information recommends dosing every 48 hours in patients receiving hemodialysis, which results in dyssynchrony of dosing and dialysis sessions every other week. Studies evaluating a dosing regimen of daptomycin thrice weekly, coinciding with dialysis, indicate that pharmacokinetic and pharmacodynamic parameters are appropriate for therapeutic success. However, to maintain adequate serum drug concentrations throughout the 72-hour interdialytic period, an additional 50% of the dose should be provided to account for the longer interval. Intradialytic dosing, with the administration of daptomycin infusion beginning during the final 30 minutes of dialysis, may also require a dose increase. Limited clinical outcomes data have been reported, but no significant safety concerns have been identified.

CONCLUSIONS

Administration of daptomycin doses thrice weekly on hemodialysis days appears to be both safe and reasonable. Doses should be increased preceding the 72-hour interdialytic period or if daptomycin is infused during dialysis.

Does economic incentive matter for rational use of medicine? China's experience from the essential medicines program

BACKGROUND

Before the new round of healthcare reform in China, primary healthcare providers could obtain a fixed 15 % or greater mark-up of profits by prescribing and selling medicines. There were concerns that this perverse incentive was a key cause of irrational medicine use. China's new Essential Medicines Program (EMP) was launched in 2009 as part of the national health sector reform initiatives. One of its core policies was to eliminate primary care providers' economic incentives to overprescribe or prescribe unnecessarily expensive drugs, which were regarded as consequences of China's traditional financing system for health institutions.

OBJECTIVES

The objective of the study was to measure changes in prescribing patterns in primary healthcare facilities after the removal of the economic incentives for physicians to overprescribe as a result of the implementation of the EMP.

METHODS

A comparison design was applied to 8,258 prescriptions in 2007 and 8,278 prescriptions in 2010, from 83 primary healthcare facilities nationwide. Indicators were adopted to evaluate medicine utilization, which included overall number of medicines, average number of Western and traditional Chinese medicines, pharmaceutical expenditure per outpatient prescription, and proportion of prescriptions that contained two or more antibiotics. We further assessed the use of medicines (antibiotics, infusion, hormones, and intravenous injection) per disease-specific prescription for hypertension, diabetes, coronary artery heart disease, bronchitis, upper respiratory tract infection, and gastritis. A difference-in-difference analysis was employed to evaluate the net policy effect.

RESULTS

Overall changes in indicators were not found to be statistically significant between the 2 years. The results varied for different diseases. The number of Western drugs per outpatient prescription decreased while that of traditional Chinese medicines increased. Overuse of antibiotics remained an extensive problem in the treatment of many diseases, though there was some significant improvement in certain diseases, like diabetes in rural areas. Medicine expenditure per prescription also decreased.

CONCLUSIONS

It seems that the removal of a perverse economic incentive alone would not lead to improvement of healthcare providers' prescribing patterns. The rationality of the Essential Medicines List and the lack of payers' and providers' meaningful involvement in the development of the policy possibly contribute to the lack of significant changes in prescribing behaviors. It is suggested that China should adopt more comprehensive policies for healthcare facilities, physicians, patients, and payers, rather than just relying on economic incentives to improve rational use of medicines.

Current use of daptomycin in cardiac surgery and postoperative intensive care

Infections due to multidrug-resistant pathogens have an increasing impact on patients undergoing cardiac surgery. Preoperative infections, such as endocarditis, and postoperative infections, including wound and device infection, influence patient outcomes. Special interest needs to be taken in patients admitted to cardiac surgical intensive care units, as these patients are at high risk for infections, particularly nosocomial pneumonia, catheter-related and wound infections. The increasing numbers of infections due to Gram-positive multidrug-resistant pathogens underline the necessity for newer antibiotics with bactericidal effects and a more favorable profile of side effects. Daptomycin, a lipopeptide antimicrobial agent with bactericide activity against Gram-positive organisms, has been successfully used in the treatment of complicated infections due to Gram-positive multidrug-resistant pathogens, especially regarding endocarditis, wound infections, device and catheter-related infections in intensive care units. In this review, the authors will summarize therapeutic potential of daptomycin in cardiac surgery and postoperative intensive care.

In vitro activity of daptomycin against Enterococcus faecalis under various conditions of growth-phases, inoculum and pH

Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezolid, tigecycline, rifampicin, gentamicin, teicoplanin, ceftriaxone and amoxicillin. Time-kill studies included colony counts at 1, 4 and 24 h of incubation. Significant bactericidal activity was defined as a decrease of ≥3log₁₀CFU/ml after 24 h of incubation. Antibiotics were tested at a low (10⁶ CFU/ml) and high (10⁹ CFU/ml) inoculum, against exponential- and stationary-phase bacteria. We also performed time kill studies of chemically growth arrested E. faecalis. Various pH conditions were used during the tests. In exponential growth phase and with a low inoculum, daptomycin alone at 60 µg/ml and the combination amoxicillin-gentamicin both achieved a 4-log₁₀ reduction in one hour on all strains. In exponential growth phase with a high inoculum, daptomycin alone was bactericidal at a concentration of 120 µg/ml. All the combinations tested with this drug were indifferent. In stationary phase with a high inoculum daptomycin remained bactericidal but exhibited a pH dependent activity and slower kill rates. All combinations that did not include daptomycin were not bactericidal in conditions of high inoculum, whatever the growth phase. The results indicate that daptomycin is the only antibiotic that may be able of overcoming the effects of growth phase and high inoculum.

Daptomycin use in patients with osteomyelitis: a preliminary report from the EU-CORE(SM) database

BACKGROUND

Osteomyelitis is a complex and heterogeneous group of infections that require surgical and antimicrobial interventions. Because treatment failure or intolerance is common, new treatment options are needed. Daptomycin has broad Gram-positive activity, penetrates bone effectively and has bactericidal activity within biofilms. This is the first report on clinical outcomes in patients with osteomyelitis from the multicentre, retrospective, non-interventional European Cubicin(®) Outcomes Registry and Experience (EU-CORE(SM)), a large database on real-world daptomycin use.

PATIENTS AND METHODS

In total, 220 patients were treated for osteomyelitis; the population was predominantly elderly, with predisposing baseline conditions such as diabetes and chronic renal/cardiac diseases.

RESULTS

Most patients (76%) received prior antibiotic treatment, and first-line treatment failure was the most frequent reason to start daptomycin. Common sites of infection were the knee (22%) or hip (21%), and the most frequently isolated pathogens were Staphylococcus aureus (33%) and coagulase-negative staphylococci (32%). Overall, 52% of patients had surgery, 55% received concomitant antibiotics and 29% received a proportion of daptomycin therapy as outpatients. Clinical success was achieved in 75% of patients. Among patients with prosthetic device-related osteomyelitis, there was a trend towards higher success rates if the device was removed. Daptomycin was generally well tolerated.

CONCLUSIONS

This analysis suggests that daptomycin is an effective and well-tolerated treatment option for osteomyelitis and highlights the importance of optimal surgical intervention and appropriate microbiological diagnosis for clinical outcomes.

[Daptomycin in outpatient antimicrobial parenteral therapy]

Daptomycin is a cyclic lipopeptide with a rapid bactericidal effect against Gram-positive bacteria. The pharmacokinetic properties of this drug allow once-daily intravenous infusion as the best posology (including a 2-minute bolus). Because of its ease of administration and excellent safety profile, daptomycin is a first-line agent for use as outpatient antimicrobial parenteral therapy (OPAT). The best evidence supporting this indication exists for the treatment of complicated and uncomplicated skin and soft tissue infections, as well as osteoarticular infections caused by Gram-positive bacteria. For the remaining indications, the use of daptomycin as OPAT should be analyzed in each patient. Information from the EUCORE Registry in Spain indicates that daptomycin has high rates of treatment success in both hospitalized patient and in those included in OPAT programs.

Serum levels of daptomycin in pediatric patients

BACKGROUND

Limited data are available on the pharmacokinetics and optimal dosage of daptomycin, a lipopeptide compound possessing activity against Gram-positive bacteria, in the pediatric population, particularly in neonates and infants. We determined serum levels of daptomycin in hospitalized pediatric patients treated with various dosages of this agent.

METHODS

Blood samples were obtained from pediatric patients of all ages with normal renal function who had received daptomycin between May 2009 and December 2010. Serum levels prior ("trough") and 30 min after end of the infusion ("peak") were determined using an ultra-performance liquid chromatography-UV detection method.

RESULTS

A total of four daptomycin dosages and four patients were studied. Three patients were infants (gestational age: 29-38 weeks, age at sampling 26-65 days) and the fourth was a 7-year-old boy. A dosage of 6 mg/kg/12 h of daptomycin to the infants resulted in trough concentrations of <4-8.4 mg/l and peak concentrations of 10.9-17.7 mg/l. Comparable levels were observed after one of the infants received a dosage of 11 mg/kg/12 h, while a further dosage increase to 15 mg/kg/12 h yielded peak concentrations of 35.5 mg/l. The 7-year-old child received a daptomycin dosage of 12 mg/kg once daily; trough and peak levels were 4.2 and 103.4 mg/l, respectively.

CONCLUSIONS

A dosage of daptomycin 6 mg/kg/12 h in small infants results in lower peak and similar trough concentrations compared with a dosage of 4 mg/kg/day administered to adults. This results suggests that daptomycin dosages of more than 6 mg/kg/12 h may be needed for this pediatric age group to achieve a similar drug exposure as adults.

[Antibiotic dose adjustment in the treatment of MRSA infections in patients with acute renal failure undergoing continuous renal replacement therapies]

Acute renal failure is frequent in critically ill patients. In those patients who need renal replacement therapy, continuous techniques are an alternative to intermittent haemodialysis. Critically ill patients often have an infection, which can lead to sepsis and renal failure. An early and adequate antibiotic treatment at correct dosage is extremely important. Methicillin resistant Staphylococcus aureus (MRSA) is a frequent nosocomial pathogen that causes a high rate of morbidity and mortality in critically ill patients. Many antibiotics are easily removed by continuous renal replacement therapies (CRRT) leading to a high risk of under dosing and therapeutic failure or resistance breakthrough. The objective of this review is to assess the clinical evidence on the pharmacokinetics and dosage recommendations of the main antibiotic groups used in MRSA treatment in patients treated with CRRT.

Daptomycin pharmacokinetics in critically ill patients receiving continuous venovenous hemodialysis

OBJECTIVE

To investigate daptomycin pharmacokinetics in critically ill patients receiving continuous venovenous hemodialysis to develop dosing recommendations.

DESIGN

Prospective, open-label pharmacokinetic study.

SETTING

: Intensive care units located within a teaching medical center.

PATIENTS

Eight adults with known/suspected Gram-positive infections receiving continuous venovenous hemodialysis and daptomycin.

INTERVENTIONS

Daptomycin at 8 mg/kg intravenously over 30 mins. Serial blood and effluent samples were collected over the next 48 hrs. Daptomycin protein binding was determined by equilibrium dialysis. Daptomycin continuous venovenous hemodialysis transmembrane clearance was determined by dividing daptomycin effluent by serum concentrations and multiplying by mean effluent production rate for each subject. Equations describing a two-compartment, open-pharmacokinetic model were fitted to each subject's daptomycin concentration-time data and pharmacokinetic parameters were determined by standard methods. Serum concentration-time profiles were simulated for two daptomycin regimens (8 mg/kg every 48 hrs and 4 mg/kg every 24 hrs).

MEASUREMENTS AND MAIN RESULTS

A total of 7.7 ± 0.6 mg/kg (mean ± sd) of daptomycin was administered, resulting in an observed peak concentration of 81.2 ± 19.0 μg/mL. Daptomycin steady-state volume of distribution (0.23 ± 0.14 L/kg) and free fraction (17.5% ± 5.0%) were increased in critically ill subjects receiving continuous venovenous hemodialysis compared with previous values reported in healthy volunteers. Daptomycin transmembrane clearance (6.3 ± 2.9 mL/min) accounted for more than half of total clearance (11.3 ± 4.7 mL/min). Simulations demonstrated 8 mg/kg daptomycin every 48 hrs would result in higher peak (88.8 ± 20.0 μg/mL vs. 53.0 ± 12.3 μg/mL) and lower trough concentrations (7.2 ± 5.2 μg/mL vs. 12.3 ± 5.1 μg/mL) than 4 mg/kg every 24 hrs.

CONCLUSIONS

Daptomycin at 8 mg/kg every 48 hrs in critically ill patients receiving continuous venovenous hemodialysis resulted in good drug exposure, achieved high peak concentrations to maximize daptomycin's concentration-dependent activity, and resulted in trough concentration that would minimize the risk of myopathy. CLINICALTRIALS.GOV IDENTIFIER: NCT00663403.

WSES consensus conference: Guidelines for first-line management of intra-abdominal infections

Intra-abdominal infections are still associated with high rate of morbidity and mortality.A multidisciplinary approach to the management of patients with intra-abdominal infections may be an important factor in the quality of care. The presence of a team of health professionals from various disciplines, working in concert, may improve efficiency, outcome, and the cost of care.A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bologna on July 2010, during the 1st congress of the WSES, involving surgeons, infectious disease specialists, pharmacologists, radiologists and intensivists with the goal of defining recommendations for the early management of intra-abdominal infections.This document represents the executive summary of the final guidelines approved by the consensus conference.

A dynamic in vitro model for evaluating antimicrobial activity against bacterial biofilms using a new device and clinical-used catheters

The activity of daptomycin compared to vancomycin against Staphylococcus epidermidis-biofilms on intravascular catheters has been evaluated using the new Sevilla device that enables to use medical grade-catheters, in an in vitro model that simulates the in vivo conditions. S. epidermidis-biofilms were obtained on polyurethane catheter segments using the Sevilla device linked to a continuous culture system for 24 h. To assess the antimicrobial activity, at this time the continuous culture system was changed to therapeutic antimicrobial concentration solutions for 48 h. At each 24 h interval time, catheter segments were taken out, washed and sonicated. Viable adherent bacteria were determined by agar plating. Data of surviving bacteria numbers attached to the catheter surface obtained with the Sevilla device showed a very good reproducibility. Daptomycin showed a good activity against S. epidermidis-biofilm on polyurethane catheter surface. After 48 h exposure to daptomycin, surviving adherent bacteria were reduced by 4 log compared to the control with no antimicrobial. Using the same model, vancomycin reduced bacterial survival by only 1.3 log. The Sevilla device enables antimicrobial agent activity against bacterial biofilms grown on the external surface of catheters used in clinical practice to be evaluated. The model used replicates as closely as possible the biofilm formed in a highly standardized way. Using this model, daptomycin demonstrates potent in vitro activity against S. epidermidis-biofilm on a polyurethane catheter; this activity was greater than that showed by vancomycin.

Antibiotic pharmacokinetic and pharmacodynamic considerations in patients with kidney disease

Although pharmacokinetic changes occurring in kidney disease are well described, pharmacodynamics in kidney disease is rarely considered. Knowledge of pharmacodynamic principles can allow a clinician to maximize an antibiotic's effectiveness while minimizing adverse effects and antibacterial resistance. An antibiotic's pharmacokinetic and pharmacodynamic profiles should drive dose adjustment decisions in patients with kidney disease. For example, although the half-lives of beta-lactams and aminoglycosides are both prolonged in these patients, beta-lactams exhibit time-dependent antibacterial activity; consequently, maintenance doses should be smaller but given at the same interval. In contrast, aminoglycosides are concentration-dependent antibiotics; hence prolongation of the dosing interval while using larger doses may be advantageous. The timing of drug administration in relation to hemodialysis may be used to achieve specific pharmacodynamic goals. Aminoglycosides given before hemodialysis generate high peaks, whereas subsequent dialytic drug removal minimizes the area under the serum concentration-time curve, potentially decreasing the risk of developing toxicity. Furthermore, new dialysis prescribing patterns (eg, automated peritoneal dialysis, nocturnal dialysis) affect pharmacokinetic and pharmacodynamic parameters in ways not appreciated by clinicians. Studies quantifying the often considerable drug removal with these therapies, as well as efforts to identify pharmacodynamic targets in patients with kidney disease are essential. This paper reviews pharmacodynamic as well as pharmacokinetic issues that should be considered when prescribing antibiotics to treat infections in this population.

Daptomycin: pharmacology and clinical use

IMPORTANCE OF THE FIELD

Infections caused by Gram-positive organisms have increased in frequency and severity. Daptomycin offers a therapeutic option in an era of increasing resistance.

AREAS COVERED IN THIS REVIEW

Literature from 1986 to present was reviewed for pharmacological, preclinical and clinical studies on daptomycin.

WHAT THE READER WILL GAIN

The pharmacological properties, resistance mechanisms and clinical applications of daptomycin are discussed. Recommendations are offered on the use of this agent for the treatment of resistant Gram-positive infections.

TAKE HOME MESSAGE

Daptomycin is a reliable agent for the treatment of Gram-positive infections. It has been shown to be effective in bacteremia and endocarditis, as well as in soft-tissue infections caused by Gram-positive organisms. Its role in the treatment of bone and joint infections is not well-defined. Resistance is currently uncommon in clinical isolates. However, emergence of resistance during therapy is a concern. This may be prevented by use of higher doses.