Cerebral Spinal Fluid Penetration of Tigecycline in a Patient with Acinetobacter baumannii Cerebritis

Intrathecal Tigecycline in the Treatment of Hospital-Acquired Meningitis: A Review of Four Cases

Objectives: Carbapenem-resistant A. baumannii is a common cause of nosocomial meningitis, and it presents a challenge in terms of treatment because of limited therapeutic options. Intravenous tigecycline has been considered a potential salvage therapy against multi-drug-resistant Acinetobacter baumannii. However, its effectiveness is limited by its poor ability to cross the blood-brain barrier. As an alternative treatment option, intrathecal tigecycline has shown promise with its minimal side effects and high concentration in cerebrospinal fluid. Methods: In this report, we present a series of four cases infected with multi-drug-resistant A. baumannii following neurosurgery and treated with intrathecal tigecycline, including antimicrobial therapy. Results: The rate of successful microbiological response was 2 out of 3 cases (66%) in whom microbiological response could be tested anytime during the intrathecal therapy, whereas the 30-day survival rate after treatment completion was ¼ (25%). Conclusion: Although intrathecal tigecycline treatment has shown relative efficacy in achieving microbiological response, its impact on overall survival is still uncertain. Further studies involving larger groups of patients are necessary to evaluate the outcomes of intrathecal tigecycline therapy.

Analysis of tigecycline in the cerebrospinal fluid and serum of patients with Acinetobacter baumannii central nervous system infection

Aim: This study aimed to establish a method to determine tigecycline (TGC) in the cerebrospinal fluid (CSF) and serum of 12 patients with multidrug-resistant Acinetobacter baumannii (MDRAB) central nervous system infection (CNSI) and evaluate the correlation of TGC in CSF and serum samples. Materials & methods: TGC in CSF and serum was detected by high-performance liquid chromatography with tandem mass spectrometry. Results: In all 12 patients, the CSF-to-serum ratio of TGC at a steady-state trough concentration ranged from 21.46 to 44.46%, and the mean value was 31.61 ± 8.13%. The correlation of TGC in CSF and serum was 0.5065. Conclusion: CNSI might have no potential to increase the penetration ability of TGC into the CSF. The correlation between the concentrations of TGC in CSF and serum at steady state was demonstrated to be positive.

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.

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.

Role of Therapeutic Drug Monitoring in the Treatment of Persistent Mycobacterium abscessus Central Nervous System Infection: A Case Report and Review of the Literature

A patient presenting with recurrent ventriculoperitoneal shunt infection was found to have Mycobacterium abscessus growing from cerebrospinal fluid (CSF), which remained persistently positive. Therapeutic monitoring of clarithromycin, imipenem, and linezolid in CSF and plasma revealed lower than expected concentrations, prompting alternative therapy and culture clearance on hospital day 42.

Intravenous plus intraventricular tigecycline-amikacin therapy for the treatment of carbapenem-resistant Klebsiella pneumoniae ventriculitis: A case report

RATIONALE

Central nervous system infections (CNSIs) are one of the most serious complications after neurosurgery, especially carbapenem-resistant bacterial meningitis. Owing to the poor blood-brain barrier permeability of most antibiotics, the treatment of CNSIs by intraventricular (IVT) administration is becoming a hot topic in clinical research. Currently, the treatment of CNSIs caused by carbapenem-resistant Klebsiella pneumoniae is mainly based on intraventricular injection of an antibiotic combined with one or more other systemic intravenous (IV) antibiotics, whereas there are few case reports of intraventricular injection of 2 antibiotics.

PATIENT CONCERNS

A 57-year-old man with an open craniocerebral injury presented with dyspnea, high fever, and seizures associated with surgery.

DIAGNOSIS

Intracranial infection caused by carbapenem-resistant K. pneumoniae was diagnosed.

INTERVENTIONS

On the advice of a clinical pharmacist, the patient was given tigecycline (100 mg IV + 3 mg IVT q12h) combined with amikacin (0.8 g IV + 30 mg IVT qd) antiinfective therapy. Ultimately, the pathogens in the cerebrospinal fluid were eradicated after 7 days, and the CNSIs were completely cured after 14 days.

OUTCOMES

The patient recovered and was discharged from the hospital without adverse reactions.

LESSONS

A series of in vitro and in vivo synergy tests of carbapenem-resistant K. pneumoniae showed that tigecycline combined with aminoglycosides had good synergistic effects and effectively suppressed bacterial resistance selection. Intravenous plus intraventricular tigecycline-amikacin seems to be a safe and effective treatment option for carbapenem-resistant K. pneumoniae CNSIs.

Successful Treatment of Postneurosurgical Ventriculitis Caused by Extensively Drug-resistant Acinetobacter baumannii in a Child: Case Report

Introduction: The incidence of postneurosurgical Acinetobacter baumannii ventriculitis/meningitis, primarily due to drug-resistant strains, has increased considerably in recent years. However, limited therapeutic options are available because most antibiotics poorly penetrate the blood-brain barrier, especially in pediatric patients. Case Presentation: A five-year-old boy developed ventriculitis due to extensively drug-resistant A. baumannii (XDRAB) after bilateral frontal external ventricular drainage for spontaneous intraventricular hemorrhage. The boy was safely and successfully treated with intraventricular (IVT)/intrathecal (ITH) polymyxin B together with intravenous tigecycline plus cefoperazone/sulbactam. Conclusions: In the present case, postneurosurgical XDRAB ventriculitis was closely associated with intraventricular hemorrhage and the placement of external ventricular drainage. IVT/ITH polymyxin B combined with intravenous tigecycline and cefoperazone sulbactam could be a therapeutic option against XDRAB ventriculitis in children.

Does Tigecycline Have a Place in Therapy for Rickettsial Infection of the Central Nervous System?

This brief report documents the safety and efficacy of high-dose tigecycline as a salvage-therapy in in a case series of five patients with serious central nervous system (CNS) rocky mountain spotted fever (RMSF). These severily ill patients were unable to take any oral drug therapy, parenteral doxycycline was unavailable and absorption of oral doxycycline was a concern in these critically ill patients. As far as we know, we report the successfull use of tigecycline for the treatment of rickettsial meningitis for the first time in Italy. We suggest more studies on tigecycline in severe CNS infections from Rickettsia species and multi-drug resistant bacteria, especially the use of tigecycline at higher than standard doses in these life-threathening infectious diseases.

Dose optimisation of antibiotics used for meningitis

PURPOSE OF REVIEW

Central nervous system (CNS) infections such as ventriculitis and meningitis are associated with significant morbidity and mortality. In part, this may be due to increased difficulties in achieving a therapeutic antibiotic concentration at the site of infection due to both the pharmacokinetic (PK) changes observed during critical illness and the reduced antibiotic penetration through the blood brain barrier. This paper reviews the pharmacodynamics (PD) and CNS PKs of antibiotics used for Gram-negative bacterial CNS infections to provide clinicians with practical dosing advice.

RECENT FINDINGS

Recent PK studies have shown that currently used intravenous antibiotic dosing regimens may not achieve a therapeutic exposure within the CNS, even for reportedly 'susceptible' bacteria per the current clinical meningitis breakpoints. Limited data exist for new β-lactam antibiotic/β-lactamase inhibitor combinations, which may be required for multidrug resistant infections. Intraventricular antibiotic administration, although not a new concept, has further evidence demonstrating improved patient outcomes compared with intravenous therapy alone, despite the ongoing paucity of PK studies guiding dosing recommendations.

SUMMARY

Clinicians should obtain the bacterial minimum inhibitory concentration when treating patients with CNS Gram-negative bacterial infections and consider the underlying PK/PD principles when prescribing antibiotics. Therapeutic drug monitoring, where available, should be considered to guide dosing. Intraventricular therapy should also be considered for patients with ventricular drains to optimise clinical outcomes.

Successful Treatment of Severe Post-craniotomy Meningitis Caused by an Escherichia coli Sequence Type 410 Strain Coharboring bla NDM - 5 and bla CTX - M - 65

Intracranial infections caused by multidrug-resistant Gram-negative bacterium have led to considerable mortality due to extremely limited treatment options. Herein, we firstly reported a clinical carbapenem-resistant Escherichia coli isolate coharboring bla NDM - 5 and bla CTX - M - 65 from a patient with post-craniotomy meningitis. The carbapenem-resistant Escherichia coli strain CNEC001 belonging to Sequence Type 410 was only susceptible to amikacin and tigecycline, both of which have poor penetration through the blood-brain barrier (BBB). The bla CTX - M - 65 gene was expressed on a 135,794 bp IncY plasmid. The bla NDM - 5 gene was located on a genomic island region of an IncX3-type plasmid pNDM5-CNEC001. Based on the characteristics of the strain, we presented the successful treatment protocol of intravenous (IV) tigecycline and amikacin combined with intrathecal (ITH) amikacin in this study. Intracranial infection caused by Escherichia coli coharboring bla NDM - 5 and bla CTX - M - 65 is rare and fatal. Continuous surveillance and infection control measures for such strain need critical attention in clinical settings.

Inadequate Cerebrospinal Fluid Concentrations of Available Salvage Agents Further Impedes the Optimal Treatment of Multidrug-Resistant Enterococcus faecium Meningitis and Bacteremia

BACKGROUND

Vancomycin-resistant Enterococcus faecium (VRE) in particular has evolved as an important cause of hospital acquired infection, especially in immunocompromised hosts.

METHODS

We present a complex case of a patient with relapsed acute myeloid leukemia who underwent allogenic hematopoietic stem cell transplantation complicated by persistent VRE bacteremia and meningitis. To optimize therapy, various blood and cerebrospinal fluid (CSF) samples were sent to a research laboratory for extensive susceptibility testing, pharmacokinetic analyses, and time-kill experiments.

RESULTS

In vitro testing revealed resistance to all first-line treatment options and CSF sampling demonstrated sub-optimal central nervous system concentrations achieved by each antimicrobial agent administered in relation to their respective MIC value. Time-kill analyses at observed CSF concentrations confirmed the lack of bactericidal activity despite use of a four-drug combination regimen.

CONCLUSIONS

This work is the first to report CSF concentrations of oritavancin and tedizolid in humans and adds to the limited data regarding in vitro susceptibility of new antimicrobial agents such as eravacycline, omadacycline, and lefamulin against VRE. Our study provides new insights into various aspects of treatment of extensively drug-resistant Enterococcus faecium meningitis and bacteremia and supports the continued pursuit of precision medicine for these challenging cases.

Spinal arachnoiditis followed by intrathecal tigecycline therapy for central nervous system infection by extremely drug-resistant Acinetobacter baumannii

In prior research, intrathecal tigecycline was successfully used to treat central nervous system infection by extensively drug-resistant Acinetobacter baumannii. However, little is known about its safe dose and adverse reactions. This study reports the case of a 28-year-old male patient who was diagnosed with central nervous system infection by extensively drug-resistant A. baumannii after the removal of a ventriculoperitoneal shunt. Intravenous and intrathecal tigecycline were administrated simultaneously. Spinal arachnoiditis was discovered after nine doses of intrathecal tigecycline. Spinal arachnoiditis was resolved after discontinuation of the antibiotic. This is the first report of an adverse reaction to intrathecal tigecycline. The case was complicated by spinal arachnoiditis, which obstructed the assessment of cerebrospinal fluid. The appropriate dose and administration schedule of intrathecal tigecycline remain to be determined.

Sequential intraventricular injection of tigecycline and polymyxin B in the treatment of intracranial Acinetobacter baumannii infection after trauma: a case report and review of the literature

BACKGROUND

Intracranial infection after craniotomy is one of the most serious postoperative complications, especially multidrug-resistant (MDR) or extensively drug-resistant (XDR) bacterial meningitis, and strongly affects the prognosis of patients. Current treatment experience regarding these infections is scarce.

CASE PRESENTATION

We report a case of severe intracranial infection of XDR Acinetobacter baumannii (A. baumannii) that was treated by intravenous (IV) injection, sequential intraventricular (IVT) injection of tigecycline and polymyxin B, and other anti-infective drugs. Good results were obtained, and the patient was eventually discharged from the hospital. This case is characterized by intracranial infection.

CONCLUSIONS

The polymyxin B IV + IVT pathway is an ideal treatment strategy for XDR A. baumannii. The tigecycline IVT pathway is also a safe treatment option.

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.

Tigecycline treatment in a liver transplant infant with carbapenem-resistant Escherichia coli infection: Case report

INTRODUCTION

During the past decade, the rate of carbapenem resistance among Enterobacteriaceae, mostly in Escherichia coli and Klebsiella pneumoniae, has significantly increased worldwide. It is a great challenge for the choice of drug treatment especially in children.Tigecycline is the first drug in the glycylcycline class of antibiotics. For children, the China Food and Drug Administration and US Food and Drug Administration postulated that tigecycline is not recommended. It must be used only as salvage therapy for life-threatening infections in critically ill children who have no alternative treatment options.

PATIENT CONCERNS

A male pediatric case of 4.5 months was blood stream infection after liver transplantation. The blood cultures obtained grew Gram-negative rods, which reportedly grew a strain of extended-spectrum β-lactamase and carbapenemases-producing Escherichia coli within 10 hours. All bacterial isolates were found to be resistant to all antimicrobial agents except aminoglycosides and tigecycline.

DIAGNOSES

Complicated intra-abdominal infection, central line-associated blood stream infection.

INTERVENTIONS

The blood stream infection with carbapenem-resistant Escherichia coli after liver transplantation was cured by tigecycline.

OUTCOMES

The patient's condition continued to improve, then transferred to general ward.

CONCLUSION

The following report, to our knowledge, is the youngest liver transplantation patient who used tigecycline treatment around the world. It provides reference and experience for the use of tigecycline in infants with severe infections.

Different influences on mitochondrial function, oxidative stress and cytotoxicity of antibiotics on primary human neuron and cell lines

Although antibiotics are generally well tolerated, their toxic effects on the central nervous system have been gained attention. In this study, we systematically investigated the neuron toxicity of antibiotics from six different classes. We show that clinically relevant concentrations of metronidazole, tigecycline, azithromycin and clindamycin but not ampicillin or sulfamethoxazole induce apoptosis of human primary neuron cells and lines. Notably, tigecycline, azithromycin and clindamycin cause neuron cell oxidative damage whereas metronidazole has no effect on reactive oxygen species (ROS) production, suggesting that metronidazole induces neuron death via ROS-independent mechanism. Tigecycline, azithromycin and clindamycin induce mitochondrial dysfunctions via targeting different mitochondrial respiratory complexes, leading to mitochondrial membrane potential disruption and energy crisis. The deleterious effects of antibiotics are reversed by pretreatment of neuron cells with antioxidant. Our work highlights the different influences of antibiotics on mitochondrial dysfunction, oxidative damage and cytotoxicity in neuron cells. We also provide a strategy to prevent the neurotoxicity.

Multidrug-Resistant Acinetobacter baumannii Ventriculostomy-Related Infection, Treated by a Colistin, Tigecycline, and Intraventricular Fibrinolysis

BACKGROUND

Acinetobacter baumannii meningitis and ventriculitis are difficult issues, because of the low diffusion of antibiotics in the cerebrospinal fluid and bacterial multidrug resistance. The presence of an infected intraventricular hematoma, constituting an equivalent of undrained abscess, may promote biofilm formation and failure of medical treatment.

CASE DESCRIPTION

In this case of ventriculostomy-related infection after ventricular hemorrhage, Acinetobacter baumannii was sensitive only to colistin and tigecycline. Despite a combination therapy involving intraventricular injections of colistin, we observed clinical and bacteriologic failure. Therefore, at day 4 of antibiotic therapy, we performed intraventricular fibrinolysis, which dissolved the clot, enabling sterilization of the cerebrospinal fluid after 48 hours.

CONCLUSION

This clinical case suggests the usefulness of intraventricular fibrinolysis to lyse the clot and optimize the action of antibiotics.

Tigecycline in the treatment of multidrug-resistant Acinetobacter baumannii meningitis: Results of the Ege study

OBJECTIVES

In this study we retrospectively reviewed A. baumannii meningitis cases treated with tigecycline including regimens and evaluated the efficacy of tigecycline in the therapy.

PATIENTS AND METHODS

Study was performed in seven tertiary-care educational hospitals from five cities of Turkey and one center from France. We extracted data and outcomes of all adult (aged >18) patients with culture proven A. baumannii meningitis treated with tigecycline including antibiotic therapy until April 2016.

RESULTS

A total of 23 patients (15 male and eight female) fulfilled our inclusion criteria. All Acinetobacter strains were carbapenem-resistant and susceptible to tigecycline. Six cases received tigecycline monotherapy while 17 received tigecycline including combination therapy (10 with colistin, 4 with netilmicin, 3 with amikacin, 4 with meropenem). Seven of 23 cases (30%) died during the tigecycline including therapy (1 in monotherapy, 4 in colistin, 2 in netilmicin, 1 amikacin, one case received tigecycline + netilmicin followed by tigecycline + colistin). Hence, overall end of treatment (EOT) success was 70%. However, since further 27% died due to additional nosocomial infections, overall clinical success (relieved symptoms at the EOT and one-month post-therapy survival without any relapse or reinfection) decreased to 43%.

CONCLUSION

We conclude that tigecycline may be an alternative in the salvage treatment of nosocomial multidrug-resistant Acinetobacter spp. meningitis. Acinetobacter spp. Meningitis.

Tigecycline Therapy in an Infant for Ventriculoperitoneal Shunt Meningitis

Shunt infections are seen in 3% to 20% of patients who have cerebrospinal fluid (CSF) shunts. Although the staphylococcal species are the most common cause of shunt-related infections, Gram-negative bacteria are increasingly reported with higher mortality rates. Tigecycline, a glycylcycline, is not approved for children. But in the era of nosocomial infections due to multidrug-resistant pathogens, it can be the life-saving option. We report an infant with ventriculoperitoneal shunt-related meningitis treated with a tigecycline combination regimen. A 5-month-old boy who had a ventriculoperitoneal shunt was admitted with meningitis. Extended spectrum β-lactamase-producing Klebsiella pneumoniae grew in the CSF. At the end of the fourth week of intravenous meropenem plus gentamicin therapy, carbapenem-resistant K pneumoniae grew in the CSF (mean inhibitory concentration value for meropenem >4 μg/mL, by E-test). The infected shunt was removed, and an external ventricular drainage catheter was inserted. With permission, intravenous tigecycline (1.2 mg/kg per dose twice a day) and intrathecal amikacin were added to the meropenem. Intrathecal amikacin could be given for only 7 days. On the sixth day of tigecycline treatment, the CSF was sterilized. Antibiotic therapy was given and consisted of a total of 60 days of meropenem and 20 days of tigecycline therapy. Because no available efficacy and safety data from randomized-controlled studies exist, tigecycline must be used only as salvage therapy, in combination with other drugs, for critically ill children who have no alternative treatment options.

Minocycline and Tigecycline: What Is Their Role in the Treatment of Carbapenem-Resistant Gram-Negative Organisms?

Carbapenem-resistant organisms are increasingly common worldwide, particularly in India and are associated with high mortality rates especially in patients with severe infection such as bacteremia. Existing drugs such as carbapenems and polymyxins have a number of disadvantages, but remain the mainstay of treatment. The tetracycline class of antibiotics was first produced in the 1940s. Minocycline, tetracycline derivative, although licensed for treatment of wide range of infections, has not been considered for treatment of multidrug-resistant organisms until recently and needs further in vivo studies. Tigecycline, a derivative of minocycline, although with certain disadvantages, has been frequently used in the treatment of carbapenem-resistant organisms. In this article, we review the properties of minocycline and tigecycline, the common mechanisms of resistance, and assess their role in the management of carbapenem-resistant organisms.

Intrathecal injection of tigecycline in treatment of multidrug-resistant Acinetobacter baumannii meningitis: a case report

The ubiquitous Acinetobacter baumannii is an important and troublesome pathogen of nosocomial infection. Multidrug-resistant A baumannii meningitis is very difficult to treat, usually with high mortality. The disease is generally associated with craniotomy, but rarely with lumbar puncture. However, in our case, a 45-year-old male construction worker suffered multidrug-resistant A baumannii meningitis associated with lumbar puncture. The patient responded poorly to the initial treatment with an intravenous infusion of tigecycline. However, later treatment with an intrathecal injection of tigecycline (concentration 1 mg/mL) at a dose of 10 mg every 12 hours proved to be highly efficacious. Thus, intrathecal injection of tigecycline should be seriously considered as a treatment for multidrug-resistant A baumannii meningitis.

Antimicrobial treatment of serious gram-negative infections in newborns

The choice of antibiotics for serious Gram-negative bacterial infections in the newborn must balance delivery of effective antibiotics to the site(s) of infection with the need to minimize selection of antibiotic resistance. To reduce the risk of selective pressure from large-scale cephalosporin usage, a penicillin-aminoglycoside combination is recommended as empiric therapy for neonatal sepsis. Where Gram-negative sepsis is strongly suspected or proven, a third-generation cephalosporin should ordinarily replace penicillin. Piperacillin-tazobactam can provide better Gram-negative cover than penicillin-aminoglycoside combinations, without the risk of selecting antibiotic resistance seen with cephalosporins, but further clinical studies are required before this approach to empiric therapy can be recommended. For antibiotic-resistant infections, a carbapenem remains the mainstay of treatment. However, rapid emergence and spread of resistance to these antibiotics means that in the future, neonatologists may have to rely on antibiotics such as colistin, whose pharmacokinetics, safety, and clinical efficacy in neonates are not well-defined.

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.

Bacterial meningitis: new therapeutic approaches

Bacterial meningitis remains a disease with high mortality and long-term morbidity. Outcome critically depends on the rapid initiation of effective antibiotic therapy. Since a further increase of the incidence of pathogens resistant to antibacterials can be expected both in community-acquired and nosocomial bacterial meningitis, the choice of an optimum initial empirical antibiotic regimen will gain significance. In this context, the use of antibiotics which are bactericidal but do not lyse bacteria, may emerge as a therapeutic option. Conversely, the role of corticosteroids, which decrease the entry of hydrophilic antibacterials into the cerebrospinal fluid, as adjunctive therapy will probably decline as a consequence of the increasing antibiotic resistance of bacteria causing meningitis. Consequent vaccination of all children at present is the most efficient manner to reduce disease burden.

Intraventricular and intrathecal colistin as the last therapeutic resort for the treatment of multidrug-resistant and extensively drug-resistant Acinetobacter baumannii ventriculitis and meningitis: a literature review

Acinetobacter baumannii ventriculitis/meningitis due to the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has become a clinical entity of considerable importance in recent years. A review of the available literature regarding intraventricular (IVT) or intrathecal (ITH) administration of colistin in MDR and XDR A. baumannii ventriculitis/meningitis was conducted and a total of 83 episodes in 81 patients were identified (71 cases in adults and 10 in children and neonates). Colistin was administered via the IVT and ITH route in 52 and 22 cases, respectively, whilst in 7 cases the exact route was not identified. The median dose of local colistin was 125000 IU (10mg) with a range of 20000 IU (1.6 mg) to 500000 IU (40 mg) in adults, whilst a dose of 2000 IU/kg (0.16 mg/kg) up to 125000 IU (10mg) was used in the paediatric population. The median duration of treatment of IVT/ITH polymyxin E was 18.5 days, whilst the median time to achieve sterilisation of cerebrospinal fluid was 4 days. The rate of successful outcome was 89%, and toxicity related to treatment mainly manifested as reversible chemical ventriculitis/meningitis was reported in nine cases (11%). Nowadays, IVT and ITH colistin represents the last resort treatment of MDR and XDR A. baumannii ventriculitis/meningitis, offering a unique, rather safe and successful mode of therapy.

Advances in treatment of bacterial meningitis

Bacterial meningitis kills or maims about a fifth of people with the disease. Early antibiotic treatment improves outcomes, but the effectiveness of widely available antibiotics is threatened by global emergence of multidrug-resistant bacteria. New antibiotics, such as fluoroquinolones, could have a role in these circumstances, but clinical data to support this notion are scarce. Additionally, whether or not adjunctive anti-inflammatory therapies (eg, dexamethasone) improve outcomes in patients with bacterial meningitis remains controversial; in resource-poor regions, where the disease burden is highest, dexamethasone is ineffective. Other adjunctive therapeutic strategies, such as glycerol, paracetamol, and induction of hypothermia, are being tested further. Therefore, bacterial meningitis is a substantial and evolving therapeutic challenge. We review this challenge, with a focus on strategies to optimise antibiotic efficacy in view of increasingly drug-resistant bacteria, and discuss the role of current and future adjunctive therapies.