Myopathy and eosinophilic pneumonia coincidentally induced by treatment with daptomycin

A 34-year-old man with 22q11.2 deletion syndrome (DiGeorge syndrome) concurrently suffered from myopathy and eosinophilic pneumonia shortly after receiving daptomycin (DAP) for right-sided infective endocarditis. The simultaneous occurrence of these phenomena in relation to DAP therapy has not been previously well described. An allergic reaction was suspected as a possible etiology of these DAP-related complications. This case highlights the need for close observation in order to detect both musculoskeletal and respiratory disorders from the start of DAP therapy. Physicians should pay more attention to this new drug, which is expected to be frequently used in various clinical settings.

Modeling economic implications of alternative treatment strategies for acute bacterial skin and skin structure infections

OBJECTIVE

The economic implications from the US Medicare perspective of adopting alternative treatment strategies for acute bacterial skin and skin structure infections (ABSSSIs) are substantial. The objective of this study is to describe a modeling framework that explores the impact of decisions related to both the location of care and switching to different antibiotics at discharge.

METHODS

A discrete event simulation (DES) was developed to model the treatment pathway of each patient through various locations (emergency department [ED], inpatient, and outpatient) and the treatments prescribed (empiric antibiotic, switching to a different antibiotic at discharge, or a second antibiotic). Costs are reported in 2012 USD.

RESULTS

The mean number of days on antibiotic in a cohort assigned to a full course of vancomycin was 11.2 days, with 64% of the treatment course being administered in the outpatient setting. Mean total costs per patient were $8671, with inpatient care accounting for 58% of the costs accrued. The majority of outpatient costs were associated with parenteral administration rather than drug acquisition or monitoring. Scenarios modifying the treatment pathway to increase the proportion of patients receiving the first dose in the ED, and then managing them in the outpatient setting or prescribing an oral antibiotic at discharge to avoid the cost associated with administering parenteral therapy, therefore have a major impact and lower the typical cost per patient by 11-20%. Since vancomycin is commonly used as empiric therapy in clinical practice, based on these analyses, a shift in treatment practice could result in substantial savings from the Medicare perspective.

CONCLUSIONS

The choice of antibiotic and location of care influence the costs and resource use associated with the management of ABSSSIs. The DES framework presented here can provide insight into the potential economic implications of decisions that modify the treatment pathway.

Clinical management of Staphylococcus aureus bacteremia: a review

IMPORTANCE

Several management strategies may improve outcomes in patients with Staphylococcus aureus bacteremia.

OBJECTIVES

To review evidence of management strategies for S. aureus bacteremia to determine whether transesophageal echocardiography is necessary in all adult cases and what is the optimal antibiotic therapy for methicillin-resistant S. aureus (MRSA) bacteremia.

EVIDENCE REVIEW

A PubMed search from inception through May 2014 was performed to identify studies addressing the role of transesophageal echocardiography in S. aureus bacteremia. A second search of PubMed, EMBASE, and the Cochrane Library from January 1990 through May 2014 was performed to find studies addressing antibiotic treatment for MRSA bacteremia. Studies reporting outcomes from antibiotic therapy for MRSA bacteremia were included. All searches, which were limited to English and focused on adults, were augmented by review of bibliographic references from included studies. The quality of evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation system with consensus of independent evaluations by at least 2 of the authors.

FINDINGS

In 9 studies with a total of 4050 patients, use of transesophageal echocardiography was associated with higher rates of a diagnosis of endocarditis (14%-28%) compared with transthoracic echocardiography (2%-15%). In 4 studies, clinical or transthoracic echocardiography findings did not predict subsequent transesophageal echocardiography findings of endocarditis. Five studies identified clinical or transthoracic echocardiography characteristics associated with low risk of endocarditis (negative predictive values from 93% to 100%). Characteristics associated with a low risk of endocarditis include absence of a permanent intracardiac device, sterile follow-up blood cultures within 4 days after the initial set, no hemodialysis dependence, nosocomial acquisition of S. aureus bacteremia, absence of secondary foci of infection, and no clinical signs of infective endocarditis. Of 81 studies of antibiotic therapy for MRSA bacteremia, only 1 high-quality trial was identified. In that study of 246 patients with S. aureus bacteremia, daptomycin was not inferior to vancomycin or an antistaphylococcal penicillin, each in combination with low-dose, short-course gentamicin (clinical success rate, 44.2% [53/120] vs 41.7% [48/115]; absolute difference, 2.4% [95% CI, -10.2% to 15.1%]).

CONCLUSIONS AND RELEVANCE

All adult patients with S. aureus bacteremia should undergo echocardiography. Characteristics of low-risk patients with S. aureus bacteremia for whom transesophageal echocardiography can be safely avoided have been identified. Vancomycin and daptomycin are the first-line antibiotic choices for MRSA bacteremia. Well-designed studies to address the management of S. aureus bacteremia are needed.

Antimicrobial salvage therapy for persistent staphylococcal bacteremia using daptomycin plus ceftaroline

PURPOSE

Guidelines recommend daptomycin combination therapy as an option for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia after vancomycin failure. Recent data suggest that combining daptomycin with a β-lactam may have unique benefits; however, there are very limited clinical data regarding the use of ceftaroline with daptomycin.

METHODS

All 26 cases from the 10 medical centers in which ceftaroline plus daptomycin was used for treatment of documented refractory staphylococcal bacteremia from March 2011 to November 2012 were included. In vitro (synergy studies, binding assays, cathelicidin LL-37 killing assays), and in vivo (virulence assays using a murine subcutaneous infection model) studies examining the effects of ceftaroline with daptomycin were also performed.

FINDINGS

Daptomycin plus ceftaroline was used in 26 cases of staphylococcal bacteremia (20 MRSA, 2 vancomycin-intermediate S aureus, 2 methicillin-susceptible S aureus [MSSA], 2 methicillin-resistant S epidermidis). Bacteremia persisted for a median of 10 days (range, 3-23 days) on previous antimicrobial therapy. After daptomycin plus ceftaroline was started, the median time to bacteremia clearance was 2 days (range, 1-6 days). In vitro studies showed ceftaroline synergy against MRSA and enhanced MRSA killing by cathelicidin LL-37 and neutrophils. Ceftaroline also induced daptomycin binding in MSSA and MRSA to a comparable degree as nafcillin. MRSA grown in subinhibitory concentrations of ceftaroline showed attenuated virulence in a murine subcutaneous infection model.

IMPLICATIONS

Ceftaroline plus daptomycin may be an option to hasten clearance of refractory staphylococcal bacteremia. Ceftaroline offers dual benefit via synergy with both daptomycin and sensitization to innate host defense peptide cathelicidin LL37, which could attenuate virulence of the pathogen.

Prevalence and detection of mixed-population enterococcal bacteremia

Mixed-population (heterogeneous) enterococcal bacteremia (MEB) is rarely reported. Based on one occasion in which Vitek2 missed a vancomycin-resistant subpopulation isolated from a patient, we developed a simple method to detect this subpopulation and determined MEB frequency. The four patients presented here had either Enterococcus faecium or Enterococcus faecalis bacteremia caused by both vancomycin-resistant enterococci (VRE) and vancomycin-susceptible enterococci (VSE). No prior common antibiotic therapy was observed, and bacteremia resolved with daptomycin, gentamicin, and/or linezolid treatment. In two cases, VRE presence was missed by Vitek2. To detect the VRE subpopulation, tryptic soy broth was inoculated from positive blood cultures and a saline suspension was inoculated to a vancomycin (6-μg/ml) (V6) plate. Two isolates from each patient were studied further. Relatedness was assessed by multilocus sequence typing, fitness was evaluated by growth curve and competition assays, and vanA presence was determined by PCR. MEB represented ∼5% of all enterococcal bacteremias. All VRE subpopulations grew on V6 plates but were missed in two instances by Vitek2. VRE and VSE isolates from each patient were closely related and did not differ in overall fitness. All four VRE isolates and 2/4 VSE isolates were vanA positive. MEBs occur regardless of prior antimicrobial therapy, are relatively common in our hospital, and are important to detect. As far as we know, this study is the first to report heterogeneous E. faecalis bacteremia. There is a simple method to detect VRE subpopulations that may be missed by Vitek2.

Rapid emergence of daptomycin resistance in clinical isolates of Corynebacterium striatum… a cautionary tale

The objective of this study was to investigate the observation of daptomycin resistance in Corynebacterium striatum, both in vivo and in vitro. We describe a case of C. striatum bacteremia in a patient with a left ventricular assist device (LVAD); the initial isolate recovered was daptomycin susceptible with a minimum inhibitory concentration (MIC) of 0.125 μg/ml. Two months later, and after daptomycin therapy, the individual became bacteremic with an isolate of C. striatum with a daptomycin MIC of >256 μg/ml. To study the prevalence of daptomycin resistance in C. striatum, clinical isolates of C. striatum were grown in broth culture containing daptomycin to investigate the emergence of resistance to this antimicrobial. Molecular typing was used to evaluate serial isolates from the index patient and the clinical isolates of C. striatum we assayed. In vitro analysis of isolates from the index patient and 7 of 11 additional C. striatum isolates exhibited the emergence of high-level daptomycin resistance, despite initially demonstrating low MICs to this antimicrobial agent. This phenotype was persistent even after serial subculture in the absence of daptomycin. Together, these data demonstrate that caution should be taken when using daptomycin to treat high-inoculum infections and/or infections of indwelling medical devices with C. striatum. To our knowledge, this is the first report characterizing the emergence of daptomycin resistance in C. striatum.

The safety and efficacy of daptomycin versus other antibiotics for skin and soft-tissue infections: a meta-analysis of randomised controlled trials

OBJECTIVE

Daptomycin, a cyclic lipopeptide that exhibits rapid, concentration-dependent bactericidal activity in vitro against a broad spectrum of Gram-positive pathogens, has now, since 2003, been approved in more than 70 countries and regions to treat skin and soft-tissue infections (SSTIs). The purpose of this meta-analysis was to compare the safety and efficacy of daptomycin with other antibiotics, especially with vancomycin which has long been considered the standard therapy for complicated SSTIs.

DESIGN

Meta-analysis of randomised controlled trials (RCTs).

DATA SOURCES

We thoroughly searched PubMed, EMBASE, Cochrane Central to identify relevant RCTs. Six RCTs with a total of 1710 patients were included in this meta-analysis.

RESULTS

The results demonstrated that the efficacy of daptomycin was at par with or maybe better than other first-line antibiotics for treating SSTIs as shown by the OR for clinical success (OR=1.05, 95% CI 0.84 to 1.31, p=0.65, I(2)=0%); daptomycin versus vancomycin subgroup (OR=1.19, 95% CI 0.77 to 1.83, p=0.43, I(2)=0%); overall microbiological success (OR=1.05, 95% CI 0.61 to 1.79, p=0.86, I(2)=42%); microbiological success of daptomycin versus comparators for Staphylococcus aureus (SA, OR=1.05, 95% CI 0.61 to 2.60, p=0.53, I(2)=47%), for methicillin-resistant S. aureus (OR=0.90, 95% CI 0.77 to 1.06, p=0.20, I(2)=56%). However, daptomycin tended to have a similar treatment-related adverse events (AEs) incidence in comparison with other antibiotics (OR=1.06, 95% CI 0.71 to 1.59, p=0.76, I(2)=41%). The trend showed that daptomycin might cause less discontinuation due to AEs and death compared with other first-line antibiotics (OR=0.71, 95% CI 0.46 to 1.10, p=0.12, I(2)=11%). Significantly more patients in the daptomyicn group had creatine phosphokinase elevation than those in the control group; however, it could be reversed when the therapy ended (OR=1.95, 95% CI 1.04 to 3.65, p=0.04, I(2)=0).

CONCLUSIONS

This meta-analysis demonstrated that the safety and efficacy of daptomycin was not inferior to that of other first-line drugs, and daptomycin tended to exhibit superior efficacy when compared with vancomycin or with comparators for SA infections; nevertheless, more high-quality RCTs are needed to draw a more credible conclusion.

Tolerability and efficacy of long-term treatment with daptomycin, ceftazidime and colistin in a patient with a polymicrobial, multidrug-resistant prosthetic joint reinfection: a case report

INTRODUCTION

Prosthetic joint infections are severe complications of joint implants. Further complications arise when polymicrobial and/or multidrug-resistant microorganisms are involved. Currently, there are limited data on the management of these infections and on the tolerability of long-term treatment with daptomycin, ceftazidime and colistin.

CASE PRESENTATION

A 55-year-old Caucasian woman who had a right hip prosthesis removed 1 year prior because of infection was admitted for prosthesis reimplantation. On admission at our hospital, anamnesis regarding etiology and management of prosthesis infection was not available. On clinical, laboratory findings and imaging studies infection was not suspected. A hip prosthesis was reimplanted. At surgery, histopathological and microbiological investigations were not taken. Three weeks after reimplantation, surgical site infection due to Enterobacter cloacae was diagnosed and oral ciprofloxacin was prescribed. Four days later, a periprosthesis fluid collection was evidenced and a percutaneous needle aspirate grew Staphylococcus epidermidis and S. haemolyticus. Enterobacter genome was also detected from the same sample. Teicoplanin and meropenem were added to ciprofloxacin without clinical improvement. Moreover, acetabular cup dislocation was documented. She underwent prosthesis explantation, debridement, and positioning of an antimicrobial mixed spacer. From the intraoperatory cultures S. epidermidis and Acinetobacter baumannii were grown. Daptomycin, ceftazidime, colistin and rifampin were administered. Four days later, rifampin was stopped due to a suspected liver toxicity. While undergoing therapy she presented recurrent episodes of wound dehiscence and on the 22nd week of treatment a further surgical debridement was performed, upon which the spacer was removed. At this time, intraoperative cultures resulted negative. Three months later, after a total of 8 months, antimicrobials were interrupted. Subsequently, a femoral transcondylar traction was positioned, and 3 weeks later a new prosthesis was reimplanted. At over 1 year after reimplantation she is well.

CONCLUSIONS

Our findings suggest that microbiologic investigations are mandatory even when prosthetic joint infection is not suspected. Molecular methods for identification of microorganisms can be used in addition to conventional cultures especially when patients are under antibiotic treatment. Daptomycin, ceftazidime and colistin can be administered for several months without side effects. Guidelines specifically addressing the diagnosis and the management of polymicrobial, multidrug-resistant prosthetic joint infections need to be developed.

Evaluation of ceftaroline, vancomycin, daptomycin, or ceftaroline plus daptomycin against daptomycin-nonsusceptible methicillin-resistant Staphylococcus aureus in an in vitro pharmacokinetic/pharmacodynamic model of simulated endocardial vegetations

Infective endocarditis (IE) caused by methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin and daptomycin has few adequate therapeutic options. Ceftaroline (CPT) is bactericidal against daptomycin (DAP)-nonsusceptible (DNS) and vancomycin-intermediate MRSA, but supporting data are limited for IE. This study evaluated the activities of ceftaroline, vancomycin, daptomycin, and the combination of ceftaroline plus daptomycin against DNS MRSA in a pharmacokinetic/pharmacodynamic (PK/PD) model of simulated endocardial vegetations (SEVs). Simulations of ceftaroline-fosamil (600 mg) every 8 h (q8h) (maximum concentration of drug in serum [Cmax], 21.3 mg/liter; half-life [t1/2], 2.66 h), daptomycin (10 mg/kg of body weight/day) (Cmax, 129.7 mg/liter; t1/2, 8 h), vancomycin (1 g) q8h (minimum concentration of drug in serum [Cmin], 20 mg/liter; t1/2, 5 h), and ceftaroline plus daptomycin were evaluated against 3 clinical DNS, vancomycin-intermediate MRSA in a two-compartment, in vitro, PK/PD SEV model over 96 h with a starting inoculum of ∼8 log10 CFU/g. Bactericidal activity was defined as a ≥ 3-log10 CFU/g reduction from the starting inoculum. Therapeutic enhancement of combinations was defined as ≥ 2-log10 CFU/g reduction over the most active agent alone. MIC values for daptomycin, vancomycin, and ceftaroline were 4 mg/liter, 4 to 8 mg/liter, and 0.5 to 1 mg/liter, respectively, for all strains. At simulated exposures, vancomycin was bacteriostatic, but daptomycin and ceftaroline were bactericidal. By 96 h, ceftaroline monotherapy offered significantly improved killing compared to other agents against one strain. The combination of DAP plus CPT demonstrated therapeutic enhancement, resulting in significantly improved killing versus either agent alone against 2/3 (67%) strains. CPT demonstrated bactericidal activity against DNS, vancomycin-intermediate MRSA at high bacterial densities. Ceftaroline plus daptomycin may offer more rapid and sustained activity against some MRSA in the setting of high-inoculum infections like IE and should also be considered.

Daptomycin versus vancomycin for osteoarticular infections due to methicillin-resistant Staphylococcus aureus (MRSA): a nested case-control study

Vancomycin is the standard antibiotic for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. While daptomycin is approved for MRSA bacteremia, its effectiveness in osteoarticular infections (OAIs) has not been established. A 1:2 nested case-control study of adult patients with MRSA OAIs admitted to an academic center from 2005 to 2010 was carried out. Clinical outcomes and drug toxicity in patients treated with daptomycin versus vancomycin were compared. Twenty patients with MRSA OAIs treated with daptomycin were matched to 40 patients treated with vancomycin. The median age of the patients was 52 years (range, 25-90), and 40 (67%) were male. Most patients had osteomyelitis (82%), predominantly from a contiguous source (87%). Forty percent were diabetics. Diabetic patients were more likely to receive vancomycin than daptomycin [20 (50%) vs. 4 (20%); p = 0.03]. Vancomycin was more often combined with antibiotics other than daptomycin [22 (55%) vs. 5 (25%); p = 0.03]. The median total antibiotic treatment duration was 48 (daptomycin) vs. 46 days (vancomycin) (p = 0.5). Ninety percent of daptomycin-treated patients had previously received vancomycin for a median of 14.5 days (range, 2-36). Clinical success rates were similar between daptomycin and vancomycin at 3 months [15 (75%) vs. 27 (68%); p = 0.8] and 6 months [14 (70%) vs. 23 (58%); p = 0.5], even after propensity score-based adjustment for antibiotic assignment. The frequency of adverse events was similar between treatment groups [1 (5%) vs. 7 (18%); p = 0.2]. Daptomycin and vancomycin achieved similar rates of clinical success and drug tolerability. Daptomycin is a reasonable alternative for treating MRSA OAIs, particularly in patients where therapy with vancomycin has not been well tolerated.

Acute generalized exanthematous pustulosis caused by daptomycin in a critically ill burn victim

Acute generalized exanthematous pustulosis (AGEP) is a self-limiting type of drug eruption that frequently occurs as a reaction to antibiotics, particularly penicillins or macrolides. Daptomycin (DAP) is a newly developed antibiotic that specifically targets methicillin-resistant Staphylococcus aureus infection. We herein present the case of a 77-year-old severe burn victim who was diagnosed with DAP-induced AGEP while receiving treatment in an intensive care unit. Although rare, physicians should be aware that the administration of DAP can cause AGEP, which may complicate the clinical course of patients with a high fever and inflammation.

Staphylococcus aureus toxic shock syndrome toxin-1 endocarditis with muscular metastatic abscesses

A 42-year-old woman, living in a nursing home for the mentally disabled, with congenital ventricular septal defect and multiple comorbidities, developed endocarditis with vegetations of the interventricular septum and the right coronary aortic leaflet. The main feature of this case was the metastatic embolism leading to multiple and muscular abscesses. Methicillin-sensitive S. aureus, spa type 253 and ST30, producing toxin shock syndrome toxin-1 was isolated from blood cultures. The patient was initially treated with beta-lactam antibiotics without showing clinical response and subsequently with daptomycin and linezolid that improved the patient's clinical symptoms. The effectiveness of treatment with daptomycin and linezolid was partly due to the ability of linezolid to reduce TSST-1 secretion. The portal of entry of the infection was not recognized. TSST-1 production by the strain might have favoured the formation of large cardiac vegetations and the subsequent metastatic dissemination to the muscles.

A retrospective study of daptomycin use in a Paris teaching-hospital

OBJECTIVE

We retrospectively studied daptomycin use during 2010 at the Bichat-Claude-Bernard teaching-hospital (Paris) to observe the evolution of daptomycin prescriptions.

PATIENTS AND METHODS

Twenty-one patients were included and several parameters were documented: site of infection, bacterial species involved, reason for daptomycin use, dose and clinical outcome.

RESULTS

Ninety-five percent of daptomycin prescritions were off-label and most did not comply with local guidelines. Fifteen of the 21 patients were cured (71%), including 9 patients of the 12 with off-label and off-local recommendation prescriptions (75%). Osteitis and Enterococcus spp endocarditis were the new indications. Daptomycin was increasingly used at higher doses: 52% of our patients were given doses above 6mg/kg. Staphylococcus spp. was the most frequent pathogen responsible for infection is our patients, followed by Enterococcus spp.

CONCLUSION

Daptomycin use is likely to evolve because of its effectiveness in the treatment of osteitis, left-sided and Enterococcus spp. infective endocarditis. It is generally used at higher doses, which are well tolerated. However, therapeutic monitoring needs to be developed. The antibiotic commission of our hospital gave new recommendations for daptomycin use in 2011.

Acute focal bacterial nephritis due to methicillin-resistant Staphylococcus aureus in an immunocompetent adult

Acute focal bacterial nephritis (AFBN) is a rare, acute focal infection of the renal parenchyma without liquefaction. The pathogenesis is thought to be due to hematogenous infection or ascending infection from the lower urinary tract. Escherichia coli has been the major pathogen isolated in prior cases, but other Gram-negative enteric pathogens and Staphylococcus aureus have been reported as well. It is well described in children and adults with diabetes and organ transplantation, but has not been previously reported in healthy adults. We report a case of an immunocompetent adult female who presented with a methicillin-resistant Staphylococcus aureus bacteremia after a skin and soft tissue infection that resulted in AFBN.

[Management of late-onset sepsis due to coagulase-negative staphylococci in neonatal intensive care units]

Coagulase-negative staphylococci (CoNS) are the most frequent cause of late-onset sepsis (LOS) in neonatal intensive care units (NICUs). Staphylococcus epidermidis is usually considered the most prevalent CoNS in this setting. However, recent reports have identified Staphylococcus capitis, another CoNS, as an emerging cause of bacteremia in NICU wards. S. capitis is the main cause of LOS in several NICUs in France, whereas this species is rarely found in adult patients from the same hospitals. S. capitis isolates from NICU infants share several striking features: they all belong to the same pulsed-field gel electrophoresis type, designated as NRCS-A, which indicates their clonal relatedness; their resistance profile reflects adaptation to antimicrobial agents specifically used in NICUs, including resistance to beta-lactams and aminoglycosides but not to fluoroquinolones, and reduced susceptibility to vancomycin; and they are associated with more severe LOS than those caused by other CoNS. The molecular characterization of NICU S. capitis isolates from several countries has shown that S. capitis NRCS-A strains have disseminated in both Western Europe (France, the United Kingdom, and Belgium) and Australia. The dissemination of such multiresistant strains imposes difficult therapeutic choices on pediatricians. As a consequence of the recent strengthening of the French and European guidelines that regulate the interpretation of clinical vancomycin susceptibility in staphylococci, a non-negligible proportion of NICU CoNS isolates (including S. capitis as well as other CoNS species) that were usually reported as vancomycin-susceptible are now categorized as vancomycin-resistant. In such cases, practitioners are faced with uncomfortable alternatives: the continued use of vancomycin in spite of the pathogen being unambiguously reported as resistant to this molecule and the use of antimicrobial agents such as linezolid or daptomycin that retain an in vitro efficacy against CoNS but whose use in neonates has not received approval by the healthcare authorities. To cope with this emerging challenge, clinical investigations of the relative tolerance and efficacy of vancomycin, linezolid, and daptomycin in NICU infants infected with these newly reported vancomycin-resistant CoNS are urgently needed.

Brazilian experience in EU-CORE: daptomycin registry and treatment of serious Gram-positive infections

Objectives

To collect data about non-controlled prescribing use of daptomycin and its impact among Brazilian patients with serious Gram positive bacterial infection, as well as the efficacy and safety outcomes.

Materials and methods

This is a multi-center, retrospective, non-interventional registry (August 01, 2009 to June 30, 2011) to collect data on 120 patients (44 patients in the first year and 76 patients in the second year) who had received at least one dose of commercial daptomycin in Brazil for the treatment of serious Gram-positive bacterial infection.

Results

Right-sided endocarditis (15.8%), complicated skin and soft tissue infections (cSSTI)-wound (15.0%) and bacteremia-catheter-related (14.2%) were the most frequent primary infections; lung (21.7%) was the most common site for infection. Daptomycin was used empirically in 76 (63.3%) patients, and methicillin-resistant Staphylococcus aureus (MRSA) was the most common suspected pathogen (86.1%). 82.5% of the cultures were obtained prior to or shortly after initiation of daptomycin therapy. Staphylococcus spp. – coagulase negative, MRSA, and methicillin-susceptible S. aureus were the most frequently identified pathogens (23.8%, 23.8% and 12.5%, respectively). The most common daptomycin dose administered for bacteremia and cSSTI was 6 mg/kg (30.6%) and 4 mg/kg (51.7%), respectively. The median duration of inpatient daptomycin therapy was 14 days. Most patients (57.1%) did not receive daptomycin while in intensive care unit. Carbapenem (22.5%) was the most commonly used antibiotic concomitantly. The patients showed clinical improvement after two days (median) following the start of daptomycin therapy. The clinical success rate was 80.8% and the overall rate of treatment failure was 10.8%. The main reasons for daptomycin discontinuation were successful end of therapy (75.8%), switched therapy (11.7%), and treatment failure (4.2%). Daptomycin demonstrated a favorable safety and tolerability profile regardless of treatment duration.

Conclusions

Daptomycin had a relevant role in the treatment of Gram-positive infections in the clinical practice setting in Brazil.

Population pharmacokinetics of daptomycin in patients affected by severe Gram-positive infections

A population pharmacokinetic analysis of daptomycin was performed based on therapeutic drug monitoring (TDM) data from 58 patients receiving doses of 4-12 mg/kg for the treatment of severe Gram-positive infections. At a daily dose of 8 mg/kg, daptomycin plasma concentrations (mean ± S.D.) were 76.9 ± 9.8 mg/L at the end of infusion and 52.7 ± 15.4 mg/L and 11.4 ± 5.4 mg/L at 0.5 h and 23 h after drug administration, respectively. The final model was a one-compartmental model with first-order elimination, with estimated clearance (CL) of 0.80 ± 0.14 L/h and a volume of distribution (V(d)) of 0.19 ± 0.05 L/kg. Creatinine clearance (CL(Cr)) was identified as having a significant influence on daptomycin CL, and a decrease in CL(Cr) of 30 mL/min from the median value (80 mL/min) was associated with a reduction of daptomycin CL from 0.80 L/h to 0.73 L/h. These results confirm that the presence of severe infection may be associated with an altered disposition of daptomycin, with an increased Vd. MICs were available in 41 patients and results showed that 38 and 31 subjects achieved AUC/MIC values associated with bacteriostatic (>400) and bactericidal effects (>800), respectively. Of note, 31 of these 41 subjects experienced a clinical improvement or were cured. Although daptomycin pharmacokinetics may be influenced by infections, effective AUC/MIC values were achieved in the majority of patients. The present model may be applied in clinical settings for a TDM routine on the basis of a sparse blood sampling protocol.

Cyclic lipodepsipeptides: a new class of antibacterial agents in the battle against resistant bacteria

In order to provide effective treatment options for infections caused by multidrug-resistant bacteria, innovative antibiotics are necessary, preferably with novel modes of action and/or belonging to novel classes of drugs. Naturally occurring cyclic lipodepsipeptides, which contain one or more ester bonds along with the amide bonds, have emerged as promising candidates for the development of new antibiotics. Some of these natural products are either already marketed or in advanced stages of clinical development. However, despite the progress in the development of new antibacterial agents, it is inevitable that resistant strains of bacteria will emerge in response to the widespread use of a particular antibiotic and limit its lifetime. Therefore, development of new antibiotics remains our most efficient way to counteract bacterial resistance.