Daptomycin Plasma and CSF Levels in Patients with Healthcare-Associated Meningitis

Management of methicillin-resistant Staphylococcus aureus bloodstream infections: a comprehensive narrative review of available evidence focusing on current controversies and the challenges ahead

INTRODUCTION

Bloodstream infections (BSIs) caused by Staphylococcus aureus are common worldwide, representing one of the most relevant issues in clinical infectious diseases practice. In particular, BSIs by methicillin-resistant S. aureus (MRSA-BSI) are still today a challenge since mortality burden remains elevated although decades of research.

AREAS COVERED

The following topics regarding MRSA-BSI were reviewed and discussed by resorting to best available evidence retrieved from PubMed/MEDLINE up to October 2024: i) epidemiology; ii) microbiology; iii) classification, with a focus on complicated and not complicated forms; iv) the structured approach to the patient; v) pharmacokinetics and pharmacodynamics of the main antimicrobial options; vi) controversies regarding the best therapeutic approach.

EXPERT OPINION

Despite ongoing efforts to better stratify and manage MRSA-BSI, there is no universally accepted classification system accurately distinguishing between uncomplicated/low risk and complicated/high risk forms. Biomarkers such as interleukin(IL)-10 hold promise in order to enable a more precise stratification, premise for an appropriate treatment plan. There is a theoretical rationale for implementing a combination therapy including a beta-lactam agent upfront, especially for patients considered at higher risk of unfavorable outcomes, but further data are necessary, and the same applies to newer adjuvants. Novel microbiological techniques may help in guiding antimicrobial duration.

Clinical Application Value of Metagenomic Next-Generation Sequencing at Perioperative Period in Patients with Central Nervous System Infections in Neurosurgical Intensive Care Unit

OBJECTIVE

This study aims to evaluate the clinical utility of metagenomic next-generation sequencing (mNGS) for diagnosing central nervous system infections (CNSIs) during the perioperative period in neurosurgical intensive care unit (ICU) patients.

METHODS

In this prospective study, we included patients suspected of CNSIs during the perioperative period who were admitted to the neurosurgical ICU at Henan Provincial People's Hospital. Clinical samples were tested using both mNGS and conventional pathogen culture methods. Based on comprehensive clinical diagnoses, patients were categorized into the CNSIs and non-CNSIs groups. The diagnostic performance of mNGS was compared with traditional methods, including time to pathogen detection and evaluation of optimal testing conditions. Additionally, the study assessed whether antibiotic resistance genes detected by mNGS could predict drug resistance phenotypes.

RESULTS

Between January 2022 and December 2023, 116 patients were enrolled, including 48 in the CNSIs group and 30 in the non-CNSIs group. mNGS identified a greater variety and quantity of pathogens compared to conventional methods. First, mNGS results were consistent with traditional culture in 5 cases. mNGS exhibited superior sensitivity (85.42% vs. 10.42%) and a higher negative predictive value (80.00% vs. 40.10%) compared to traditional cultures. Second, only 8.33% of CNSIs patients showed identical pathogens in both cerebrospinal fluid and blood samples. Third, 28.6% of cerebrospinal fluid samples with an mNGS detection interval of more than 7 days showed complete pathogen consistency, while 60% of samples with a detection interval of less than 3 days were consistent. Moreover, the antibiotic resistance genes detected by mNGS largely corresponded with the resistance phenotypes identified by antibiotic susceptibility testing.

CONCLUSIONS

To sum up, mNGS offers excellent diagnostic accuracy and significant clinical value in CNSIs diagnosis during the perioperative period in the neurosurgical ICU, complementing traditional culture methods effectively.

Development of VRE meningitis due to haematogenous spread while on high-dose daptomycin therapy

Introduction

Vancomycin-resistant Enterococcus faecium (VRE) meningitis accounts for only 0.3%-4.0% of bacterial meningitis cases and typically occurs following neurosurgical intervention. We describe a rare case of a patient without neurological devices in situ or a recent neurological procedure who developed VRE meningitis via haematogenous spread. Optimal treatment for VRE meningitis is unknown.

Case presentation

A 67-year-old male with end-stage liver failure underwent liver transplantation complicated by VRE bacteraemia and subsequently developed VRE meningitis while on high-dose daptomycin therapy (12 mg/kg/day). Due to clinical and microbiological failure with daptomycin, he was switched to linezolid and symptoms resolved rapidly. He completed 2 weeks of linezolid, fully recovered, and continued to do well without complications at the 5 month follow-up.

Conclusions

This case highlights the severity of VRE infections in solid organ transplant recipients and raises concerns about daptomycin penetration into the CNS. Linezolid could be considered the preferred treatment for VRE CNS infections rather than high-dose daptomycin.

Analysis of Vacuum-Assisted Closure-Assisted Antibiotic Irrigation in Treatment of Severe Neurosurgical Central Nervous System Infections

Objective: Severe neurosurgical central nervous system infections (sNCNSIs) are among the most serious complications of neurosurgical disease. Conventional methods have shown a poor prognosis. This study aims to analyze the clinical characteristics of vacuum-assisted closure (VAC) in sNCNSIs with the help of antibiotic irrigation treatment. Patients and Methods: A retrospective study was performed for patients diagnosed with sNCNSIs. A VAC device was placed on the incision after debridement and the surgical cavity was rinsed with antibiotic agents in the VAC group. Meanwhile the surgical cavity was drained after debridement in the control group. Medical data were reviewed and analyzed. Results: Twenty-eight patients met the inclusion criteria, including 18 cases in the VAC group and 10 cases in the control group. The basic medical data showed no differences. Bacteria was isolated from 24 (85.7%) patients. The cure rate was significantly higher in the VAC group (p < 0.05). The cure rate in patients with multi-drug-resistant (MDR) infections was significantly higher in patients treated with VAC therapy (p < 0.05). The prognosis evaluated by Glasgow Outcome Score (GOS) between the two groups showed significant difference (p < 0.05). No re-infection in the VAC group occurred in the follow-up period. Conclusions: It is suggested that VAC-assisted antibiotic irrigation is safe and effective for patients with severe NCNSIs and can improve the prognosis dramatically. The results can provide a new effective and reasonable therapeutic strategy for patients with sNCNSIs.

Clinical Experience with Off-Label Intrathecal Administration of Selected Antibiotics in Adults: An Overview with Pharmacometric Considerations

Drain-associated intracerebral infections are life-threatening emergencies. Their treatment is challenging due to the limited penetration of antibiotics to the site of infection, resulting in potentially inadequate exposure. The emergence of multidrug-resistant pathogens might force the use of off-label intrathecal (IT) doses of antibiotics. We reviewed the literature on general aspects determining intrathecal dosing regimen, using pharmacometric knowledge. We summarised clinical experience with IT doses of antibiotics that are usually not used intrathecally, as well as the outcome of the cases and concentrations reached in the cerebrospinal fluid (CSF). Factors determining the IT regimen are the size of the ventricle system and the CSF drainage volume. With regard to pharmacometrics, pharmacokinetic/pharmacodynamic indices are likely similar to those in non-cerebral infections. The following number (N) of cases were described: benzylpenicillin (>50), ampicillin (1), ceftazidime (2), cephaloridine (56), ceftriaxone (1), cefotiam (1), meropenem (57), linezolid (1), tigecycline (15), rifampicin (3), levofloxacin (2), chloramphenicol (3) and daptomycin (8). Many side effects were reported for benzylpenicillin in the 1940-50s, but for the other antibiotics, when administered correctly, all side effects were minor and reversible. These data might help when choosing an IT dosing regimen in case there is no alternative option due to antimicrobial resistance.

Contemporary pharmacologic treatments of MRSA for hospitalized adults: rationale for vancomycin versus non-vancomycin therapies as first line agents

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important pathogen in the hospital setting and causes significant morbidity and mortality each year. Since the initial discovery over 60 years ago, vancomycin has remained a first-line treatment for many different types of MRSA infections. However, significant concerns related to target attainment and nephrotoxicity have spurred efforts to develop more effective agents in the last two decades.

AREAS COVERED

Newer anti-MRSA antibiotics that have been approved since 2000 include linezolid, daptomycin, and ceftaroline. As clinical evidence has accumulated, these newer agents have become more frequently used, and some are now recommended as co-first-line options (along with vancomycin) in clinical practice guidelines. For this review, a scoping review of the literature was conducted to support our findings and recommendations.

EXPERT OPINION

Vancomycin remains an important standard of care for MRSA infections but is limited with respect to nephrotoxicity and rapid target attainment. Newer agents such as linezolid, daptomycin, and ceftaroline have specific indications for treating different types of MRSA infections; however, newer agents also have unique attributes which require consideration during therapy.

Effectiveness and Safety of Linezolid Versus Vancomycin, Teicoplanin, or Daptomycin against Methicillin-Resistant Staphylococcus aureus Bacteremia: A Systematic Review and Meta-Analysis

Vancomycin (VCM) and daptomycin (DAP) are standard therapies for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, despite concerns regarding clinical utility and growing resistance. Linezolid (LZD) affords superior tissue penetration to VCM or DAP and has been successfully used as salvage therapy for persistent MRSA bacteremia, indicating its utility as a first-choice drug against MRSA bacteremia. In a systematic review and meta-analysis, we compared the effectiveness and safety of LZD with VCM, teicoplanin (TEIC), or DAP in patients with MRSA bacteremia. We evaluated all-cause mortality as the primary effectiveness outcome, clinical and microbiological cure, hospital length of stay, recurrence, and 90-day readmission rates as secondary effectiveness outcomes, and drug-related adverse effects as primary safety outcomes. We identified 5328 patients across 2 randomized controlled trials (RCTs), 1 pooled analysis of 5 RCTs, 1 subgroup analysis (1 RCT), and 5 case-control and cohort studies (CSs). Primary and secondary effectiveness outcomes were comparable between patients treated with LZD versus VCM, TEIC, or DAP in RCT-based studies and CSs. There was no difference in adverse event incidence between LZD and comparators. These findings suggest that LZD could be a potential first-line drug against MRSA bacteremia as well as VCM or DAP.

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.

The Blood-Brain Barrier and Pharmacokinetic/Pharmacodynamic Optimization of Antibiotics for the Treatment of Central Nervous System Infections in Adults

Bacterial central nervous system (CNS) infections are serious and carry significant morbidity and mortality. They encompass many syndromes, the most common being meningitis, which may occur spontaneously or as a consequence of neurosurgical procedures. Many classes of antimicrobials are in clinical use for therapy of CNS infections, some with established roles and indications, others with experimental reporting based on case studies or small series. This review delves into the specifics of the commonly utilized antibacterial agents, updating their therapeutic use in CNS infections from the pharmacokinetic and pharmacodynamic perspectives, with a focus on the optimization of dosing and route of administration that have been described to achieve good clinical outcomes. We also provide a concise synopsis regarding the most focused, clinically relevant information as pertains to each class and subclass of antimicrobial therapeutics. CNS infection morbidity and mortality remain high, and aggressive management is critical in ensuring favorable patient outcomes while averting toxicity and upholding patient safety.

Tissue Penetration of Antimicrobials in Intensive Care Unit Patients: A Systematic Review—Part I

The challenging severity of some infections, especially in critically ill patients, makes the diffusion of antimicrobial drugs within tissues one of the cornerstones of chemotherapy. The knowledge of how antibacterial agents penetrate tissues may come from different sources: preclinical studies in animal models, phase I–III clinical trials and post-registration studies. However, the particular physiopathology of critically ill patients may significantly alter drug pharmacokinetics. Indeed, changes in interstitial volumes (the third space) and/or in glomerular filtration ratio may influence the achievement of bactericidal concentrations in peripheral compartments, while inflammation can alter the systemic distribution of some drugs. On the contrary, other antibacterial agents may reach high and effective concentrations thanks to the increased tissue accumulation of macrophages and neutrophils. Therefore, the present review explores the tissue distribution of beta-lactams and other antimicrobials acting on the cell wall and cytoplasmic membrane of bacteria in critically ill patients. A systematic search of articles was performed according to PRISMA guidelines, and tissue/plasma penetration ratios were collected. Results showed a highly variable passage of drugs within tissues, while large interindividual variability may represent a hurdle which must be overcome to achieve therapeutic concentrations in some compartments. To solve that issue, off-label dosing regimens could represent an effective solution in particular conditions.

Current Perspectives on the Diagnosis and Management of Healthcare-Associated Ventriculitis and Meningitis

Ventriculitis or post-neurosurgical meningitis or healthcare-associated ventriculitis and meningitis (VM) is a severe infection that complicates central nervous system operations or is related to the use of neurosurgical devices or drainage catheters. It can further deteriorate patients who have already presented significant neurologic injury and is associated with high morbidity, mortality, and poor functional outcome. VM can be difficult to distinguish from aseptic meningitis, inflammation that follows hemorrhagic strokes and neurosurgical operations. The associated microorganisms can be either skin flora or nosocomial pathogens, most commonly, Gram-negative bacteria. Classical microbiology can fail to isolate the culprit pathogen. Novel cerebrospinal fluid (CSF) biomarkers and molecular microbiology can fill the diagnostic gap and expedite pathogen identification and treatment. The pathogens may demonstrate significant resistant patterns and their antibiotic treatment can be difficult, as many important drug classes, including the beta-lactams and the glycopeptides, hardly penetrate to the CSF, and do not achieve therapeutic levels at the site of the infection. Treatment modifications, such as higher daily dose and prolonged or continuous administration, might increase antibiotic levels in the site of infection and facilitate pathogens clearance. However, in the case of therapeutic failure or infection due to difficult-to-treat bacteria, the direct antibiotic instillation into the CSF, in addition to the intravenous antibiotic delivery, may help in the resolution of infection. However, intraventricular antibiotic therapy may result in aseptic meningitis and seizures, concerning the administration of aminoglycosides, polymyxins, and vancomycin. Meanwhile, bacteria form biofilms on the catheter or the device that should routinely be removed. Novel neurosurgical treatment modalities comprise endoscopic evacuation of debris and irrigation of the ventricles. VM prevention includes perioperative antibiotics, antimicrobial impregnated catheters, and the implementation of standardized protocols, regarding catheter insertion and manipulation.

Staphylococcus haemolyticus meningitis and bacteremia in an allogenic stem cell transplant patient

Staphylococcus haemolyticus is a rare cause of bacterial meningitis and most commonly occurs as a nosocomial infection in patients' post-neurosurgery. We report a patient post-allogenic stem cell transplant, with no prior history of neurosurgical procedures, who developed S. haemolyticus meningitis and bacteremia following central catheter-related bloodstream infection. The patient failed therapy with vancomycin and daptomycin but was successfully treated with a prolonged course of linezolid. We review the pharmacological management of coagulase negative Staphylococcus (CoNS) meningitis, with a focus on the pharmacokinetic properties of vancomycin, daptomycin and linezolid within the cerebrospinal fluid (CSF).

Antimicrobial use in central nervous system infections

PURPOSE OF REVIEW

Central nervous system (CNS) infections are associated with high rates of morbidity and mortality. The purpose of this review is to summarize current antimicrobial therapies, as well as, updates in the management of community-acquired meningitis and healthcare-associated meningitis and ventriculitis.

RECENT FINDINGS

Due to the increasing rates of multidrug resistant and extensively-drug resistant organisms, available antimicrobials are limited. Novel treatment options include newer systemic antimicrobials and antimicrobials that have previously limited data in the management of CNS infections. Although limited by retrospective data, intrathecal (IT) and intraventricular (IVT) routes of administration offer the opportunity for antimicrobials that conventionally have minimal cerebrospinal fluid (CSF) penetration to achieve high CSF concentrations while minimizing systemic exposure.

SUMMARY

Updates in the use of systemic, IT, and IVT antimicrobials offer promise as therapeutic options for CNS infections. Additional pharmacokinetic and prospective data are needed to confirm these findings.

Central nervous system infections and antimicrobial resistance: an evolving challenge

PURPOSE OF REVIEW

Antimicrobial resistance is an increasing threat to patients also in nosocomial central nervous system (CNS) infections. The present review focusses on optimizing intravenous treatment in order to achieve sufficient concentrations of antibiotics in the different compartments of the CNS when the causative pathogens have reduced sensitivity to antibiotics or/and the impairment of the blood-cerebrospinal fluid (CSF) and blood-brain barrier is mild.

RECENT FINDINGS

Experience has been gathered with treatment protocols for several established antibiotics using increased doses or continuous instead of intermittent intravenous therapy. Continuous infusion in general does not increase the average CSF concentrations (or the area under the concentration-time curve in CSF) compared to equal daily doses administered by short-term infusion. In some cases, it is postulated that it can reduce toxicity caused by high peak plasma concentrations. In case reports, new β-lactam/β-lactamase inhibitor combinations were shown to be effective treatments of CNS infections.

SUMMARY

Several antibiotics with a low to moderate toxicity (in particular, β-lactam antibiotics, fosfomycin, trimethoprim-sulfamethoxazole, rifampicin, vancomycin) can be administered at increased doses compared to traditional dosing with low or tolerable adverse effects. Intrathecal administration of antibiotics is only indicated, when multiresistant pathogens cannot be eliminated by systemic therapy. Intravenous should always accompany intrathecal treatment.

High-Dose Daptomycin and Clinical Applications

OBJECTIVE

To evaluate evidence for high-dose daptomycin (doses ≥ 8 mg/kg/d).

DATA SOURCES

A PubMed/MEDLINE literature search was performed (January 2000 to December 2020) using the search terms daptomycin, high dose, and dosing. Review article references and society guidelines were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials, observational studies, retrospective studies, meta-analyses, and systematic reviews reporting on high-dose daptomycin were included.

DATA SYNTHESIS

Experimentally, daptomycin outperforms other antimicrobials for high inoculum and biofilm-associated infections. Clinically, high-dose daptomycin is supported as salvage and first-line therapy for endocarditis and bacteremia, primarily when caused by methicillin-resistant Staphylococcus aureus (when vancomycin minimum inhibitory concentration is >1 mg/L) and Enterococcus. High-dose daptomycin appears effective for osteomyelitis and central nervous system infections, although comparative studies are lacking. High dosing in renal replacement therapy requires considering clearance modality to achieve exposures like normal renal function. Weight-based dosing in obesity draws concern for elevated exposures, although high doses have not been evaluated kinetically in obesity. Some data show benefits of high doses in overweight populations. Burn patients clear daptomycin more rapidly, and high doses may only achieve drug exposures similar to standard doses (6 mg/kg).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review analyzes the efficacy and safety of high-dose daptomycin in serious gram-positive infections. Discussion of specific infectious etiologies and patient populations should encourage clinicians to evaluate their daptomycin dosing standards.

CONCLUSIONS

The efficacy of high-dose daptomycin and limited safety concerns encourage clinicians to consider high-dose daptomycin more liberally in severe gram-positive infections.

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.

Intrathecal Antibacterial and Antifungal Therapies

Intrathecal administration of anti-infectives is indicated in central nervous system infections by multiresistant pathogens when drugs that can reach adequate cerebrospinal fluid (CSF) concentrations by systemic therapy are not available. Antibiotics that readily pass the blood-brain and blood-CSF barriers and/or that have low toxicity allowing an increase in the daily dosage should not be used for intrathecal therapy. Intrathecal therapy is accompanied by systemic treatment. Antibacterials indispensable for intrathecal therapy include aminoglycosides, colistin, daptomycin, tigecycline, and vancomycin. Limited experience suggests the utility of the antifungals amphotericin B and caspofungin. Intraventricular administration ensures distribution throughout the CSF compartment, whereas intralumbar dosing often fails to attain adequate antibiotic concentrations in the ventricles. The individual dose is determined by the estimated size of the CSF space and by the estimated clearance from CSF. For moderately lipophilic anti-infectives with a molecular weight above approximately 1,000 g/mol, as well as for hydrophilic drugs with a molecular weight above approximately 400 g/mol, one daily dose is normally adequate. The ventricular drain should be clamped for 15 to 120 min to facilitate the distribution of the anti-infective in the CSF space. Therapeutic drug monitoring of the trough levels is necessary only in cases of therapeutic failure.

Multidrug-Resistant Staphylococcus epidermidis Ventriculostomy-Related Infection Successfully Treated by Intravenous Ceftaroline after Failure of Daptomycin Treatment

BACKGROUND

Ventriculostomy-related infection with multidrug-negative strains are challenging to treat. We report the use of new antibiotics in such a case.

CASE DESCRIPTION

We report the case of a neurosurgical intensive care unit patient who developed ventriculostomy-related infection with a multidrug-resistant Staphylococcus epidermidis. Vancomycin, recommended in such cases, was not used due to high minimal inhibitory concentrations and concerns for lack of pharmacokinetic/pharmacodynamic target attainment. Daptomycin and ceftaroline remained the only treatment options. Daptomycin was shown microbiologically ineffective after 10 treatment days, with undetectable cerebrospinal fluid (CSF) concentration. Ceftaroline, a novel beta-lactam agent to which the strain showed susceptibility, was thus used. Serum and CSF samples were assessed for antibiotic concentrations. Our results show that CSF bacterial clearance was obtained after 6 days of such treatment. Serum and CSF samplings showed low penetration ratios (2.6%-4.8%), probably due to mild inflammatory CSF profile, with CSF concentration at minimal inhibitory concentration level.

CONCLUSIONS

We observed than even in the case of mild meningeal inflammation, ceftaroline penetration in CSF, although moderate, enabled efficient bacterial clearance and clinical efficacy, in adjunction to correct ventriculoperitoneal shunt management.

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.

Combining Ceftriaxone with Doxycycline and Daptomycin Reduces Mortality, Neuroinflammation, Brain Damage, and Hearing Loss in Infant Rat Pneumococcal Meningitis

Despite appropriate antibiotic therapy, pneumococcal meningitis (PM) is associated with a case fatality rate of up to 30% in high-income countries. Survivors often suffer from severe lifelong disabilities. An excessive inflammatory reaction drives the pathophysiology, leading to brain damage and neurologic sequelae. We aimed to improve the outcome of experimental PM by simultaneously targeting different pathophysiological mechanisms with combined adjunctive therapies previously shown to be neuroprotective. In vitro, the anti-inflammatory effects of doxycycline and daptomycin were evaluated on primary rat astroglial cells stimulated with Streptococcus pneumoniae Eleven-day-old infant Wistar rats were infected intracisternally with S. pneumoniae and randomized for treatment with ceftriaxone or combination adjuvant therapy consisting of ceftriaxone, daptomycin, and doxycycline. During acute PM, combined-adjuvant therapy with ceftriaxone, daptomycin, and doxycycline increased the survival rate from 64.1% to 85.8% (P < 0.01) and alleviated weight loss compared to ceftriaxone monotherapy (P < 0.01). Levels of inflammatory cytokines were significantly reduced by combined-adjuvant therapy in vitro (P < 0.0001) and in cerebrospinal fluid in vivo (P < 0.05). In infected animals treated with combined adjunctive therapy, cortical damage was significantly reduced (P < 0.05), and animals showed a trend toward better hearing capacity 3 weeks after the infection (P = 0.089), an effect which was significant in mildly infected animals (48 decibels [dB] versus 67.22 dB; P < 0.05). These mildly infected animals showed significantly reduced cochlear fibrous occlusion (P < 0.01). By combining nonbacteriolytic daptomycin and anti-inflammatory doxycycline with ceftriaxone, the previously reported beneficial effects of the drugs were cumulated and identified the triple-antibiotic therapy as a promising therapeutic option for pediatric PM.

Antibiotic exposure at the site of infection: principles and assessment of tissue penetration

Introduction: Since the majority of bacterial infections occur at sites outside the bloodstream, antibiotic tissue concentrations are of significant relevance to optimize treatment. The aim of this review is to aid the clinician in choosing optimal regimens for the treatment of extravascular infections. Areas covered: We discuss the principles of antibiotic tissue penetration and assess different approaches to obtain data on this subject. Finally, we present tissue penetration data for several relevant groups of antibiotic agents in a number of extravascular sites. Data were obtained from an extensive literature search in PubMed until February 2019. Expert opinion: There is still a long way to go before reliable information about tissue penetration of antibiotics is sufficiently available to serve as a basis for the design of optimal strategies for drug and dose selection. At this moment, there is a lack of robust data on tissue penetration, where both the sampling and measurement techniques as well as the relationship between tissue concentrations and clinical outcome of antibiotic treatment have to be better defined.