Cerebrospinal fluid penetration of high-dose daptomycin in suspected Staphylococcus aureus meningitis

Ceftaroline in CNS and ocular infections: a case series

Background

There are limited data describing outcomes of patients treated with ceftaroline for infections with CNS or ocular involvement.

Objectives

To describe outcomes of patients treated with ceftaroline for methicillin-resistant staphylococcal infections involving the CNS or eye.

Patients and methods

This was a retrospective review of 10 patients at an academic medical centre who received ceftaroline for CNS or ocular infections.

Results

All patients were treated with ceftaroline as part of a combination for salvage therapy. Four patients died, whereas six patients experienced clinical cure. Only one experienced microbiological recurrence.

Conclusions

These preliminary data suggest that ceftaroline may be an option for salvage therapy of severe staphylococcal infections when used in combination.

Addition of daptomycin for the treatment of pneumococcal meningitis: protocol for the AddaMAP study

BACKGROUND

The leading cause of acute bacterial meningitis in adults is Streptococcus pneumoniae. This infection is associated with high rates of mortality and morbidity related, among other factors, to the excessive host response to the pneumococcal lysis. Experimental in vitro and in vivo data show that the combination of corticosteroids/third-generation cephalosporins and the non-lytic antibiotic, daptomycin, has synergistic effects with (1) a rapid cerebrospinal fluid sterilisation, (2) less brain damages and (3) less loss of cognitive performances. Despite these encouraging results, daptomycin has never been evaluated in adult patients with pneumococcal meningitis.

METHODS AND ANALYSIS

The AddaMAP trial is a phase II, open-label, Simon's two-stage, multicentre trial that has been designed to assess the efficacy and safety of adding daptomycin (10 mg/kg/d for 8 days) to the recommended treatment (corticosteroids+third generation cephalosporin) in adults with confirmed pneumococcal meningitis. The main endpoint is the disability-free survival (defined as modified Rankin Scale mRS≤2) at day 30. Secondary outcomes are overall mortality, disability at D30 and D90 (mRS, Glasgow Coma Scale and Glasgow Outcome Scales, mini-mental score), hearing loss (Hearing Handicap Inventory Test at D30 and D90, routine audiometric test and Hearing-it test at D30), and quality of life (12-item Short Form Survey and WHO QOL BREF). Seventy-two analysable patients are required.

ETHICS AND DISSEMINATION

The study protocol was approved by the Institutional Review Board of the IDF 1 of the ethics committee on 16 January 2018, and authorisation was obtained from the Agence Nationale de Securité des Médicaments et des Produits de Santé on 22 September 2017. The results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03480191.

Daptomycin for the treatment of acute bacterial meningitis: a narrative review

BACKGROUND

There is a growing interest in the utilization of daptomycin for the treatment of multi-drug resistant, Gram-positive infections. Pharmacokinetic studies suggest that daptomycin could penetrate into the cerebrospinal fluid, albeit to a small extent. The objective of this review was to evaluate the available clinical evidence for daptomycin use in acute bacterial meningitis of both pediatric and adult patients.

METHODS

Electronic databases were searched up to June 2022 for studies published on the topic. The inclusion criteria were met if the study reported the use of intravenous daptomycin (more than a single dose) for the treatment of diagnosed acute bacterial meningitis.

RESULTS

A total of 21 case reports were identified that met the inclusion criteria. These suggest that daptomycin could be safe and effective alternative in achieving clinical cure of meningitis. In these studies, daptomycin was used in the event of treatment failure, patient intolerance, or bacterial resistance to first-line agents.

CONCLUSIONS

Daptomycin has potential to be an alternative to standard care for meningitis caused by Gram-positive bacteria in the future; however, more robust research is required to establish an optimal dosing regimen, duration of therapy, and place in therapy for the management of meningitis.

A Systematic Review of Studies Reporting Antibiotic Pharmacokinetic Data in the Cerebrospinal Fluid of Critically Ill Patients with Uninflamed Meninges

Ventriculostomy-associated infections in critically ill patients remain therapeutically challenging because of drug- and disease-related factors that contribute to suboptimal antibiotic concentrations in cerebrospinal fluid. Optimal antibiotic dosing for the treatment and prevention of such infections should be based on robust and contextually specific pharmacokinetic data. The objects of this study were to describe and critically appraise studies with reported antibiotic concentrations or pharmacokinetic data in cerebrospinal fluid of critically ill patients without meningeal inflammation. We systematically reviewed the literature to identify published reports and studies describing antibiotic concentrations, pharmacokinetics, and pharmacokinetics/pharmacodynamics in cerebrospinal fluid of critically ill patients with uninflamed meninges. Fifty-eight articles met the inclusion criteria. There was significant heterogeneity in methodologies and results. When available, antibiotic pharmacokinetic parameters displayed large intersubject variability. Intraventricular dosing achieved substantially higher antibiotic concentrations in cerebrospinal fluid than did intravenous doses. Few studies conducted a robust pharmacokinetic analysis and described relevant clinical pharmacokinetic/pharmacodynamic indices and exposure targets in cerebrospinal fluid. Robust and clinically relevant antibiotic pharmacokinetic data describing antibiotic disposition in cerebrospinal fluid are necessary. Such studies should use a standardized approach to accurately describe pharmacokinetic variability. These data should ideally be tied to clinical outcomes whereby therapeutic targets in the cerebrospinal fluid can be better defined. Altered dosing strategies, in conjunction with exploring the utility of therapeutic drug monitoring, can then be developed to optimize antibiotic exposure with the goal of improving outcomes in this difficult-to-treat patient group.

La pharmacologie des antibiotiques dans le liquide cérébrospinal

Le liquide cérébrospinal (LCS) est produit par les plexus choroïdes des ventricules cérébraux avec pour rôle de protéger le système nerveux central des agressions mécaniques (chocs) et infectieuses (virus, bactéries, parasites) et de lui apporter des nutriments essentiels à son fonctionnement optimal. Il est anatomiquement à l'interface entre le compartiment sanguin, le liquide interstitiel cérébral et le compartiment lymphatique. Sa composition est fortement influencée par ces structures. Deux barrières permettent de réguler le passage moléculaire dans le système nerveux central et limitent fortement l'accès à ce dernier : la barrière hématoencéphalique et la barrière hématoméningée. La diffusion des antibiotiques dans le LCS, mais également dans le parenchyme cérébral dépend de plusieurs facteurs : la taille de la molécule, sa lipophilie, la liaison aux protéines plasmatiques et l'intégrité des barrières hématoencéphalique et hématoméningée. Les phénomènes d'inflammation méningée observés dans les méningites bactériennes augmentent la perméabilité des barrières et facilitent la diffusion des agents antibiotiques. Les molécules diffusant le mieux dans le LCS sont les fluoroquinolones, le linézolide, l'association triméthoprime- sulfaméthoxazole, la rifampicine et la fosfomycine. Les bêtalactamines présentent une diffusion assez faible mais qui augmente fortement en cas d'inflammation méningée. Des posologies journalières très élevées permettent de contourner l'écueil de la diffusion. De nombreux paramètres influencent la diffusion des antibiotiques dans le LCS. Le choix de l'antibiothérapie adaptée se fait en fonction de ces paramètres et du type d'infection à traiter en concertation pluridisciplinaire.

Novel and preclinical treatment strategies in pneumococcal meningitis

PURPOSE OF REVIEW

Pneumococcal meningitis is the most frequent form of bacterial meningitis in Europe and the United States. Although early antimicrobial and adjuvant therapy with dexamethasone have helped to improve disease outcome in adults, mortality and morbidity rates remain unsatisfactorily high, emphasizing the need for additional treatment options. Promising targets for adjuvant therapy have been identified recently and will be the focus of this review.

RECENT FINDINGS

Brain disease in pneumococcal meningitis is caused by direct bacterial toxicity and excessive meningeal inflammation. Accordingly, promising targets for adjuvant therapy comprise limiting the release of toxic bacterial products and suppressing inflammation in a way that maximally protects against tissue injury without hampering pathogen eradication by antibiotics. Among the agents tested so far in experimental models, complement inhibitors, matrix-metalloproteinase inhibitors, and nonbacteriolytic antibiotics or a combination of the above have the potential to more efficiently protect the brain either alone (e.g., in children and outside the high-income settings) or in addition to adjuvant dexamethasone. Additionally, new protein-based pneumococcal vaccines are being developed that promise to improve disease prevention, namely by addressing the increasing problem of serotype replacement seen with pneumococcal conjugate vaccines.

SUMMARY

Pneumococcal meningitis remains a life-threatening disease requiring early antibiotic and targeted anti-inflammatory therapy. New adjuvant therapies showed promising results in animal models but need systematic clinical testing.

Antibiotic Distribution into Cerebrospinal Fluid: Can Dosing Safely Account for Drug and Disease Factors in the Treatment of Ventriculostomy-Associated Infections?

Ventriculostomy-associated infections, or ventriculitis, in critically ill patients are associated with considerable morbidity. Efficacious antibiotic dosing for the treatment of these infections may be complicated by altered antibiotic concentrations in the cerebrospinal fluid due to variable meningeal inflammation and antibiotic properties. Therefore, doses used to treat infections with a higher degree of meningeal inflammation (such as meningitis) may often fail to achieve equivalent exposures in patients with ventriculostomy-associated infections such as ventriculitis. This paper aims to review the disease burden, infection rates, and common pathogens associated with ventriculostomy-associated infections. This review also seeks to describe the disease- and drug-related factors that influence antibiotic distribution into cerebrospinal fluid and provide a critical appraisal of current dosing of antibiotics commonly used to treat these types of infections. A Medline search of relevant articles was conducted and used to support a review of cerebrospinal fluid penetration of vancomycin, including critical appraisal of the recent paper by Beach et al. recently published in this journal. We found that in the intensive care unit, ventriculostomy-associated infections are the most common and serious complication of external ventricular drain insertion and often result in prolonged patient stay and increased healthcare costs. Reported infection rates are extremely variable (between 0 and 45%), hindered by the inherent diagnostic difficulty. Both Gram-positive and Gram-negative organisms are associated with such infections and the rise of multi-drug-resistant pathogens means that effective treatment is an ongoing challenge. Disease factors that may need to be considered are reduced meningeal inflammation and the presence of critical illness; drug factors include physiochemical properties, degree of plasma-protein binding, and affinity to active transporter proteins present in the blood-cerebrospinal fluid barrier. The relationship between cerebrospinal fluid antibiotic exposures in the setting of ventriculostomy-associated infection and clinical response has not been fully elucidated for many of the antibiotics commonly used in its treatment. More thorough and clinically relevant investigations are needed to better define blood pharmacokinetic/pharmacodynamics targets and optimal therapeutic exposures for treatment of ventriculostomy-associated infections. It is hoped that this future research will be able to provide clearer recommendations for clinicians frequently faced with dosing-related dilemmas when treating patients with these challenging infections.

Adjuvant non-bacteriolytic and anti-inflammatory combination therapy in pneumococcal meningitis: an investigation in a mouse model

OBJECTIVES

Therapy with antibiotics, dexamethasone, and supportive intensive care has improved the prognosis of pneumococcal meningitis, but mortality remains high. Here, we investigated an adjunctive combination therapy of the non-bacteriolytic antibiotic daptomycin plus several anti-inflammatory agents to identify the currently most promising adjunctive combination therapy for pneumococcal meningitis.

METHODS

C57BL/6 mice were infected by injection of pneumococci into the cisterna magna. Treatment was begun 21 h after infection, and consisted of ceftriaxone plus (a) dexamethasone, (b) dexamethasone plus daptomycin, (c) daptomycin, (d) daptomycin plus an anti-IL1 antibody, (e) daptomycin plus roscovitine, or (f) daptomycin plus an anti-C5 antibody. Animals were followed until 45 h after infection. Furthermore, adjunctive daptomycin plus anti-C5 antibodies were assessed in a long-term follow-up.

RESULTS

Adjunctive treatment with daptomycin and an anti-C5 antibody was superior to adjunctive dexamethasone and reduced disease symptoms (clinical score 1.1 ± 1.1 versus 5.0 ± 2.7, p < 0.0083), improved explorative activity (open field test 17.8 ± 8.2 versus 7.4 ± 4.3 crossed fields/2 minutes, p < 0.0083), and reduced hearing impairment (thresholds for click stimulus 96.1 ± 14.7 versus 114.8 ± 9.3 dB SPL, p < 0.0083) in the acute stage. Furthermore, explorative activity (14.4 ± 7.3 crossed fields/2 minutes versus 6.3 ± 7.2, p < 0.05) and cognitive function (t-maze test, exploration time previously unknown alley 72.4 ± 14.3 versus 48.7 ± 25.6%, p < 0.05) was improved at 2 weeks after infection. Treatment with daptomycin plus an anti-IL-1β antibody or roscovitine was not of significant benefit in comparison to adjunctive therapy with dexamethasone.

CONCLUSIONS

An adjunctive combination of the non-lytic antibiotic daptomycin plus an anti-C5 antibody was superior to standard therapy with adjunctive dexamethasone in the treatment of pneumococcal meningitis.

Bacterial meningitis: insights into pathogenesis and evaluation of new treatment options: a perspective from experimental studies

Bacterial meningitis is associated with high mortality and morbidity rates. Bacterial components induce an overshooting inflammatory reaction, eventually leading to brain damage. Pathological correlates of neurofunctional deficits include cortical necrosis, damage of the inner ear and hippocampal apoptosis. The hippocampal dentate gyrus is important for memory acquisition and harbors a neuronal stem cell niche, thus being potentially well equipped for regeneration. Adjuvant therapies aimed at decreasing the inflammatory reaction, for example, dexamethasone, and those protecting the brain from injury have been evaluated in animal models of the disease. They include nonbacteriolytic antibiotics (e.g., daptomycin), metalloproteinase inhibitors and modulators of the immunological response, for example, granulocyte colony-stimulating factor. Increasing research interest has recently been focused on interventions aimed at supporting regenerative processes.

An updated approach to healthcare-associated meningitis

Among hospital-associated infections, healthcare-associated central nervous system infections are quite important because of high morbidity and mortality rates. The causative agents of healthcare-associated meningitis differ according to the status of immune systems and underlying diseases. The most frequent agents are Gram-negative bacilli (Pseudomonas spp., Acinetobacter spp., Escherichia coli and Klebsiella pneumoniae) and Gram-positive cocci (Staphylococcus aureus and coagulase-negative staphylococci). There are currently several problems in the treatment strategies of healthcare-associated meningitis due to a globally increasing resistance problem. Strategies targeting multidrug-resistant pathogens are especially limited. This review focuses on healthcare-associated meningitis and the current treatment strategies with a particular focus on methicillin-resistant Staphylococcus aureus (MRSA) meningitis.

Clinical pharmacokinetics of antibacterials in cerebrospinal fluid

In the past 20 years, an increased discrepancy between new available antibacterials and the emergence of multidrug-resistant strains has been observed. This condition concerns physicians involved in the treatment of central nervous system (CNS) infections, for which clinical and microbiological success depends on the rapid achievement of bactericidal concentrations. In order to accomplish this aim, the choice of drugs is based on their disposition toward the cerebrospinal fluid (CSF), which is influenced by the physicochemical characteristics of antibacterials. A reduced distribution into CSF has been documented for beta-lactams, especially cephalosporins and carbapenems, on the basis of their hydrophilic nature. However, they represent a cornerstone of the majority of combined therapeutic schemes for their ability to achieve bactericidal concentrations, especially in the presence of inflamed meninges. The good tolerability of beta-lactams makes possible high daily dose intensities, which may be associated with increased probability of cure. Furthermore, the adoption of continuous infusion seems to be a fruitful option. Fluoroquinolones, namely moxifloxacin, and antituberculosis drugs, together with the agents such as linezolid, reach the highest CSF/plasma concentration ratio, which is greater than 0.8, and for most of these drugs it is near 1. For all drugs that are currently used for the treatment of CNS infections, the evaluation of pharmacokinetic/pharmacodynamic parameters, on the basis of dosing regimens and their time-dependent or concentration-dependent pattern of bacterial killing, remains an important aspect of clinical investigation and medical practice.

Pharmacokinetics of antibacterial agents in the CSF of children and adolescents

The adequate management of central nervous system (CNS) infections requires that antimicrobial agents penetrate the blood-brain barrier (BBB) and achieve concentrations in the CNS adequate for eradication of the infecting pathogen. This review details the currently available literature on the pharmacokinetics (PK) of antibacterials in the CNS of children. Clinical trials affirm that the physicochemical properties of a drug remain one of the most important factors dictating penetration of antimicrobial agents into the CNS, irrespective of the population being treated (i.e. small, lipophilic drugs with low protein binding exhibit the best translocation across the BBB). These same physicochemical characteristics determine the primary disposition pathways of the drug, and by extension the magnitude and duration of circulating drug concentrations in the plasma, a second major driving force behind achievable CNS drug concentrations. Notably, these disposition pathways can be expected to change during the normal process of growth and development. Finally, CNS drug penetration is influenced by the nature and extent of the infection (i.e. the presence of meningeal inflammation). Aminoglycosides have poor CNS penetration when administered intravenously. Intrathecal gentamicin has been studied in children with more promising results, often exceeding the minimum inhibitory concentration. There are very limited data with intrathecal tobramycin in children. However, in the few patients that have been studied, the CSF concentrations were highly variable. Penicillins generally have good CNS penetration. Aqueous penicillin G reaches greater concentrations than procaine or benzathine penicillin. Concentrations remain detectable for ≥ 12 h. Of the aminopenicillins, both ampicillin and parenteral amoxicillin reach adequate CNS concentrations; however, orally administered amoxicillin resulted in much lower concentrations. Nafcillin and piperacillin are the final two penicillins with pediatric data: their penetration is erratic at best. Cephalosporins vary greatly in regard to their CSF penetration. Few first- and second-generation cephalosporins are able to reach higher CSF concentrations. Cefuroxime is the only exception and is usually avoided due to its adverse effects and slower sterilization of the CSF than third-generation agents. Ceftriaxone, cefotaxime, ceftazidime, cefixime and cefepime have been studied in children and are all able to adequately penetrate the CSF. As with penicillins, concentrations are greatest in the presence of meningeal inflammation. Meropenem and imipenem are the only carbapenems with pediatric data. Imipenem reaches higher CSF concentrations; however, meropenem is preferred due to its lower incidence of seizures. Aztreonam has also demonstrated favorable penetration but only one study has been completed in children. Both chloramphenicol and sulfamethoxazole/trimethoprim (cotrimoxazole) penetrate into the CNS well; however, significant toxicities limit their use. The small size and minimal protein binding of fosfomycin contribute to its favorable CNS PK. Although rarely used, it achieves higher concentrations in the presence of inflammation and accumulation is possible. Linezolid reaches high CSF concentrations; however, more frequent dosing might be required in infants due to their increased elimination. Metronidazole also has very limited information but it demonstrated favorable results similar to adult data; CSF concentrations even exceeded plasma concentrations at certain time points. Rifampin (rifampicin) demonstrated good CNS penetration after oral administration. Vancomycin demonstrates poor CNS penetration after intravenous administration. When combined with intraventricular therapy, CNS concentrations are much greater. Of the antituberculosis agents, isoniazid, pyrazinamide and streptomycin have been studied in children. Isoniazid and pyrazinamide have favorable CSF penetration. Streptomycin appears to produce unpredictable CSF levels. No pediatric-specific data are available for clindamycin, daptomycin, macrolides, tetracyclines, and fluoroquinolones. Daptomycin, fluoroquinolones, and tetracyclines have demonstrated favorable CNS penetration in adults; however, data are limited due to their potential pediatric-specific toxicities and newness within the marketplace. Macrolides and clindamycin have demonstrated poor CNS penetration in adults and thus have not been studied in pediatrics.

Daptomycin plus trimethoprim/sulfamethoxazole combination therapy in post-neurosurgical meningitis caused by linezolid-resistant Staphylococcus epidermidis

Post-neurosurgical infection is a serious complication that occurs in approx. 4% of all patients undergoing neurosurgical procedures and is associated with high morbidity and mortality rates and prolonged length of intensive care unit (ICU) stay. Coagulase-negative staphylococci (CoNS), especially methicillin-resistant Staphylococcus epidermidis (MRSE), are the most frequent pathogens involved in CNS post-neurosurgical meningitis. Treatment is challenging especially in patients with meningitis due to multidrug- resistant (MDR) CONS. Herein, we report a unique case of post-neurosurgical meningitis due to MRSE resistant to linezolid (a molecular analysis revealed the presence of the mutation G2576T on domain V of the 23S rRNA gene) and with reduced susceptibility to glycopeptides, successfully treated with a combination of daptomycin at 10 mg/kg daily plus trimethoprim/sulfamethoxazole (TMP/SMX). This antibiotic combination showed an indifferent interaction in in vitro studies. Daptomycin serum and cerebrospinal fluid (CSF) concentrations, determined through blood and CSF samples drawn just prior to and 4 h after the third dose, were 18.9-0.78 and 51.65-3.1 mg/L, respectively. These values allowed us to approximate a 5-6% penetration rate of the drug through an inflamed blood-brain barrier. In conclusion, although further studies are needed, combination of high-dose daptomycin plus TMP/SMX is a reasonable option for treatment of meningitis caused by multidrug-resistant S. epidermidis.

Adjunctive daptomycin attenuates brain damage and hearing loss more efficiently than rifampin in infant rat pneumococcal meningitis

Exacerbation of cerebrospinal fluid (CSF) inflammation in response to bacteriolysis by beta-lactam antibiotics contributes to brain damage and neurological sequelae in bacterial meningitis. Daptomycin, a nonlytic antibiotic acting on Gram-positive bacteria, lessens inflammation and brain injury compared to ceftriaxone. With a view to a clinical application for pediatric bacterial meningitis, we investigated the effect of combining daptomycin or rifampin with ceftriaxone in an infant rat pneumococcal meningitis model. Eleven-day-old Wistar rats with pneumococcal meningitis were randomized to treatment starting at 18 h after infection with (i) ceftriaxone (100 mg/kg of body weight, subcutaneously [s.c.], twice a day [b.i.d.]), (ii) daptomycin (10 mg/kg, s.c., daily) followed 15 min later by ceftriaxone, or (iii) rifampin (20 mg/kg, intraperitoneally [i.p.], b.i.d.) followed 15 min later by ceftriaxone. CSF was sampled at 6 and 22 h after the initiation of therapy and was assessed for concentrations of defined chemokines and cytokines. Brain damage was quantified by histomorphometry at 40 h after infection and hearing loss was assessed at 3 weeks after infection. Daptomycin plus ceftriaxone versus ceftriaxone significantly (P < 0.04) lowered CSF concentrations of monocyte chemoattractant protein 1 (MCP-1), MIP-1α, and interleukin 6 (IL-6) at 6 h and MIP-1α, IL-6, and IL-10 at 22 h after initiation of therapy, led to significantly (P < 0.01) less apoptosis, and significantly (P < 0.01) improved hearing capacity. While rifampin plus ceftriaxone versus ceftriaxone also led to lower CSF inflammation (P < 0.02 for IL-6 at 6 h), it had no significant effect on apoptosis and hearing capacity. Adjuvant daptomycin could therefore offer added benefits for the treatment of pediatric pneumococcal meningitis.

Bacterial meningitis: current therapy and possible future treatment options

Despite targeted therapy, case-fatality rates and neurologic sequelae of bacterial meningitis remain unacceptably high. The poor outcome is mainly due to secondary systemic and intracranial complications. These complications seem to be both a consequence of the inflammatory response to the invading pathogen and release of bacterial components by the pathogen itself. Therefore, within the last decades, research has focused on the mechanism underlying immune regulation and the inhibition of bacterial lysis in order to identify new targets for adjuvant therapy. The scope of this article is to give an overview on current treatment strategies of bacterial meningitis, to summarize new insights on the pathophysiology of bacterial meningitis, and to give an outlook on new treatment strategies derived from experimental models.

Pharmacokinetics of single-dose daptomycin in patients with suspected or confirmed neurological infections

There are currently few or no published data on the amount of cerebrospinal fluid (CSF) penetration of daptomycin in patients with suspected or documented neurosurgical infections. We conducted a prospective study, assessing the pharmacokinetics and CSF penetration of a single intravenous daptomycin dose administered at 10 mg/kg, based on total body weight (TBW), in six neurosurgical patients with indwelling external CSF shunts with suspected or documented meningitis or ventriculitis. Each patient had four blood and CSF samples drawn simultaneously at specific times after the end of infusion: 30 min, 6 h, 12 h, and 24 h. Pharmacokinetic parameters of daptomycin in serum were calculated using standard noncompartmental methods, and daptomycin was assayed using high-performance liquid chromatography (for serum) or liquid chromatography with mass spectrometry (for CSF). The mean (± standard deviation [SD]) maximum measured daptomycin concentrations were 93.7 ± 17.3 mg/liter in serum at 0.5 h postinfusion and 0.461 ± 0.51 mg/liter in CSF at 6 h postinfusion. The mean (± SD) daptomycin minimum concentrations were 13.8 ± 4.8 mg/liter in serum at 24 h postinfusion and 0.126 ± 0.12 mg/liter in CSF at 0.5 h postinfusion. The mean daptomycin penetration, determined by the area under the concentration-time curve in CSF (AUC(CSF))/(AUC(serum) ratio), was 0.8%. Corrected for protein binding, the overall CSF penetration was 11.5%. Additional pharmacokinetic studies evaluating multiple and/or higher dosages of daptomycin are necessary in human subjects to better characterize the CSF penetration of daptomycin in neurosurgical patients.

Case report of a successful treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and MRSA/vancomycin-resistant Enterococcus faecium cholecystitis by daptomycin

A 72-year-old man, receiving 8 mg daptomycin/kg body weight/day for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, was diagnosed with MRSA/vancomycin-resistant Enterococcus faecium (VRE) cholecystitis (daptomycin MIC values, 1 and 2 mg/liter, respectively). After the fifth drug dose, the bile concentration of daptomycin was 66 mg/liter 5 min after drug administration, with the biliary concentration/MIC values higher than 30 for both bacterial strains. Therefore, daptomycin achieved therapeutic levels in bile, hence suggesting a role for the drug in the treatment of MRSA/VRE cholecystitis.

Treatment of meningitis caused by vancomycin-resistant Enterococcus faecium: high-dose and combination daptomycin therapy

OBJECTIVE

To report 3 successful treatments of vancomycin-resistant Enterococcus faecium meningitis in adults using daptomycin and either linezolid or gentamicin.

CASE SUMMARY

Three case reports involving males (aged 58-78 years) are presented; in each case (trigeminal nerve microvascular decompression and subdural hygroma; paraspinal abscess; and hydrocephalus with subsequent craniotomy and ventriculo-peritoneal shunt placement) CSF examination revealed vancomycin-resistant Enterococcus (VRE) susceptible to daptomycin, gentamicin, and/or linezolid. Threeto four-week treatment regimens with daptomycin 6-12 mg/kg and either gentamicin or linezolid led to clinical resolution and microbiological clearance of infection.

DISCUSSION

Daptomycin has previously been shown to be successful in treating methicillin-resistant Staphylococcus aureus-associated meningitis and other serious VRE and enterococcal infections. Higher than approved doses of daptomycin were used in 2 cases where in theory higher CSF concentrations would thus be obtained. Gentamicin and linezolid were added to daptomycin therapy based on in vitro data synergy results and because of documented successful treatment for VRE meningitis, respectively.

CONCLUSIONS

The difficulty in treating VRE CSF infections involves both drug kinetics and microbial resistance factors, as well as external factors such as foreign bodies like shunts. This report highlighted 3 cases where daptomycin use in concert with either gentamicin or linezolid was successful in treating this infection. Additional controlled trials will be helpful in identifying the best strategies when using daptomycin to treat CSF infections.