Outcomes in meningitis/ventriculitis treated with intravenous or intraventricular plus intravenous colistin

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.

An International, Multicenter Feasibility Study on Active and Continuous Irrigation With Cerebrospinal Fluid Exchange for Improving Outcomes in Cerebral Ventriculitis

BACKGROUND AND OBJECTIVES

Cerebral ventriculitis remains a challenging neurosurgical condition because of poor outcomes including mortality rates of nearly 80% and a prolonged course of treatment in survivors. Despite current conventional management, outcomes in some cases remain unsatisfactory, with no definitive therapeutic guidelines. This feasibility study aims to explore the use of a novel active, continuous irrigation and drainage system (IRRAflow [IRRAS AB]) combined with intraventricular drug delivery for patients with cerebral ventriculitis.

METHODS

We conducted a multicenter, international, retrospective study of patients with ventriculitis who were treated with use of the IRRAflow system. Data collected included patient demographics, comorbidities, admission Glasgow Coma Scale score, baseline modified Rankin Scale (mRS) score, and imaging findings. Catheter occlusions, infections, and shunt placement were recorded for outcome assessment, along with discharge mRS scores and in-hospital deaths.

RESULTS

Four centers contributed data for a total of 21 patients who had IRRAflow placement for treatment of ventriculitis. Thirteen (61.9%) were men (mean age = 49.8 ± 14.87 years). The median baseline mRS score was 1. The median Glasgow Coma Scale score at admission was 13. The etiology of ventriculitis was iatrogenic in 12 (57.1%) patients and secondary to an abscess in 9 (42.9%). No cases reported hemorrhage or failure of IRRAflow placement. Antibiotics were administered through the IRRAflow system in 13 (61.9%) cases in addition to systemic dosing. Sixteen (76.2%) patients had significant clinical improvement and resolution of ventriculitis. Seven (33.3%) patients required shunt placement after resolution because of persistent hydrocephalus. There were 6 (28.6%) in-hospital deaths.

CONCLUSION

The use of active irrigation with drainage for continuous delivery of intraventricular irrigation fluid with antibiotics led to dramatically low mortality. In our case series, it led to a marked improvement in neurological status, imaging findings, and cerebrospinal fluid profiles, making it a technically feasible and safe treatment for ventriculitis.

Ventriculitis due to multidrug-resistant gram-negative bacilli associated with external ventricular drain: evolution, treatment, and outcomes

Introduction

Nosocomial infectious ventriculitis caused by multidrug-resistant (MDR) Gram-negative bacilli associated with external ventricular drainage (EVD) placement poses a significant mortality burden and hospital costs.

Objectives

This study aims to analyze the characteristics, ventriculitis evolution, treatment, and outcomes of patients with ventriculitis due to MDR Gram-negative bacilli associated with EVD placement.

Methods

A retrospective cohort study focusing on patients with nosocomial infection caused by MDR Gram-negative bacilli while on EVD was conducted from 2019 to 2022. Medical, laboratory, and microbiological records were collected. The antibiotic resistance of the Gram-negative bacilli isolated in the cerebrospinal fluid (CSF) of patients was analyzed. The risk factors were identified using univariate risk models and were analyzed using survival curves (Cox regression). An adjusted Cox proportional hazards model was also constructed.

Results

Among 530 patients with suspected EVD-associated ventriculitis, 64 patients with isolation of Gram-negative bacilli in CSF were included. The estimated mortality was 78.12%. Hemorrhages (intracranial, subarachnoid, and intraventricular) were observed in 69.8% of patients. Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequently isolated bacilli. In the univariate analysis, significant risk factors for mortality included arterial hypertension, a Glasgow Coma Scale (GCS) score of ≤ 8, invasive mechanical ventilation (IMV) upon hospital admission and during hospitalization, septic shock, and ineffective treatment. The adjusted Cox proportional hazards model revealed that septic shock (HR = 3.3, 95% CI = 1.5-7.2; p = 0.003) and ineffective treatment (HR = 3.2, 1.6-6.5, 0.001) were significant predictors. A high resistance to carbapenems was found for A. baumannii (91.3%) and P. aeruginosa (80.0%). Low resistance to colistin was found for A. baumannii (4.8%) and P. aeruginosa (12.5%).

Conclusion

Ineffective treatment was an independent hazard factor for death in patients with ventriculitis caused by MDR Gram-negative bacilli associated with EVD.

Intrathecal or intraventricular antimicrobial therapy for post-neurosurgical Gram-negative bacillary meningitis or ventriculitis: a systematic review and meta-analysis

PURPOSE

Extensively-drug-resistant Gram-negative bacteria (XDR GNB)-related post-neurosurgical infection is closely related to mortality, which represents a major challenge for neurosurgeons. There is an urgent need to review and evaluate methods to reduce mortality.

METHODS

Both international and Chinese databases were searched independently from their inception to 15 June 2023. A meta-analysis was conducted using RevMan 5.4 to compare the efficacy and safety of intravenous (IV) treatment in combination with intrathecal or intraventricular (ITH/IVT) treatment with IV treatment alone for post-neurosurgical meningitis or ventriculitis due to GNB. Mortality, microbiological clearance and adverse events were considered as primary outcomes.

RESULTS

In total, 18 eligible studies involving 602 patients were included in the meta-analysis. The IV + ITH/IVT group was associated with significantly lower mortality (especially in the XDR GNB subgroup) and acceptable safety. In terms of microbiological clearance, a significant decrease was shown in the XDR GNB subgroup. Significant benefits were shown in laboratory parameters and clinical symptoms after patients were treated with ITH/IVT.

CONCLUSION

Additional ITH/IVT treatment may promote XDR GNB clearance and reduce mortality. In addition, ITH/IVT administration can improve clinical symptoms and cerebrospinal fluid indicators of patients with post-neurosurgical infections. Significantly, ITH/IVT treatment does not increase the incidence of adverse events at the recommended dose.

Investigation of risk factors for external ventricular drainage‑associated central nervous system infections in patients undergoing neurosurgery

Meningitis/ventriculitis (MV) is an illness which can occur as a complication following neurosurgical procedures. Devices such as an external ventricular drain (EVD) are also related to considerable complications, such as infections. The present study examined the risk factors associated with central nervous system (CNS) infections associated with the external ventricle drainage system. The present retrospective study included all patients hospitalized between April, 2011 and August, 2018 who had been receiving therapy with EVD for developed hydrocephalus. A total of 48 out of 65 patients were classified into two groups as follows: Patients without MV (group A) and patients who developed MV (group B). The durations of hospital stay and intensive care unit (ICU) stay were significantly lower in group A (32.4±24 and 21.1±11 days, respectively) compared to group B (54.7±37 and 42±24 days, respectively) (P=0.027 and P=0.001, respectively). The Acute Physiological and Chronic Health Evaluation II (APACHE II) score and EVD distance from the wound exit side to the burr hole were significantly lower in the survivors compared to the non-survivors (17.5±6 and 15.4±4 vs. 22.5±6 and 39.8±38, respectively). Receiver operating characteristic analysis revealed that the APACHE II score with an area under the curve [(AUC) of 0.677, P=0.044, and 95% confidence interval (CI) of (0.516-0.839)] and a cut-off value of 14 could predict mortality with a sensitivity of 100% and a specificity of 71%; the EVD distance from the wound exit side from the burr hole with an AUC of 0.694 (P=0.028), 95% CI of 0.521-0.866 and a cut-off value of 11.5 mm could predict mortality with a sensitivity of 88% and a specificity of 83%. On the whole, the present study demonstrates that the EVD-related distance from the wound exit side of the burr hole can predict poor outcomes due to CNS infections in patients undergoing neurosurgery.

Outcomes in meningitis‑ventriculitis treated with intravenous or intrathecal plus intravenous colistin: A meta‑analysis

The aim of the present meta-analysis was to provide further evidence on the management of bacterial ventriculitis or meningitis (BVM) and to compare the efficacy of intravenous (IV) or intravenous plus intrathecal (IV/ITH) treatment with colistin. The present meta-analysis included full-text articles published between 1980 and 2020 that compared outcomes in meningitis-ventriculitis treated with IV or IV/ITH colistin. The collected variables included the first author's name, country, study period covered, publication year, the total number of patients and follow-up, Glasgow Coma Scale score upon admission, treatment duration, Acute Physiological and Chronic Health Evaluation II score, the length of intensive unit (ICU) stay, treatment efficacy and mortality for both groups. To avoid publication bias, the final aim was to collect a homogenous pool of manuscripts, including only articles that compared only two modalities. After applying all exclusion and inclusion criteria, seven of 55 articles were left in the final article pool. The total number of patients in those seven articles was 293, divided into two groups (186 in the IV and 107 in the IV/ITH group). As regards ICU stay and mortality, the findings illustrated a statistically significant difference between the two groups. On the whole, the findings of the present study support the addition of ITH colistin to its IV administration for the effective treatment of BVM.

Adverse Events and Drug Resistance in Critically Ill Patients Treated with Colistimethate Sodium: A Review of the Literature

The adverse events related to sodium colistimethate have had variability regarding the prevalence of nephrotoxicity, neurotoxicity, and less frequent respiratory depression. In recent years, its use has been relevant due to the increase of multidrug-resistant bacteria since it is considered the last-line drug, being its main adverse event and reason for discrepancies between authors' nephrotoxicity. The indiscriminate use of antibiotic therapy has generated multiple mechanisms of resistance, the most common being related to Colistin, the bactericidal escape effect. Based on the search criteria, no randomized clinical trials were identified showing safety and efficacy with the use of Colistin, inferring that the application of the appropriate dose is governed by expert opinion and retrospective and prospective observational studies, which confounding factors such as the severity of the patient and the predisposition to develop acute renal failure are constant. In this review, we focus on identifying the mechanism of nephrotoxicity and bacterial resistance, where much remains to be known.

Treatment of Carbapenem-Resistant Multidrug-Resistant Gram-Negative Bacilli with Intracerebroventricular Injection of Polymyxin B: A Retrospective Study

Purpose

We evaluated the efficacy and administration time of intraventricular (IVT) polymyxin B in the treatment of carbapenem-resistant and multidrug-resistant/extensively drug-resistant (MDR/XDR) Gram-negative bacilli in central nervous system (CNS) infections and investigated prognostic factors.

Patients and Methods

This retrospective analysis comprised 41 post-surgical carbapenem-resistant CNS infections from October 2016 to October 2021. All patients were treated with effective intravenous antibiotics and IVT polymyxin B. Patient characteristics, therapeutic procedure, symptoms, cerebrospinal fluid (CSF) examination, laboratory tests, and complications were recorded. The effectiveness of IVT polymyxin B was evaluated using temperature, Glasgow Coma Scale, CSF contents, bacterial clearance rate, cure rate, and mortality. Mortality between early (7 days) and late administration of IVT polymyxin B was compared. Prognostic factors were evaluated using the pupillary light reflex and multiloculated hydrocephalus.

Results

The 41 patients acquired carbapenem-resistant MDR/XDR bacteria, including 24 Klebsiella pneumoniae, 15 Acinetobacter baumannii, 3 Pseudomonas aeruginosa, and 1 Enterobacter cloacae. The bacterial clearance rate was 32/41 (78.0%), and 9 patients (22.0%) with uncured bacterial infections died. Adverse events included 1 case of skin pigmentation. Among the 32 cured patients, 31 received a ventriculoperitoneal shunt, and 1 patient had an extraventricular drainage tube removed. Mortality in the late (>7 days) group was higher (39.1% vs 0%, P < 0.05). The group without pupillary light reflex showed a higher death rate (41.2% vs 8.3%; P < 0.05). The multiloculated hydrocephalus group had a higher mortality rate than that of the normal group (34.8% vs 5.6%, P < 0.05). All 32 cured patients were followed up for 9 to 66 months, and all survived without recurrent infections.

Conclusion

Intraventricular polymyxin B is an effective treatment for carbapenem-resistant MDR/XDR Gram-negative bacilli, with a 78% cure rate and significant mortality reduction if administered within 7 days of bacterial identification. Multiloculated hydrocephalus and the pupillary light reflex may be used as prognostic indicators of mortality.

Detection of multidrug-resistant Acinetobacter baumannii by metagenomic next-generation sequencing in central nervous system infection after neurosurgery: A case report

Background

Central nervous system (CNS) infection is one of the most serious complications after neurosurgery. Traditional clinical methods are difficult to diagnose the pathogen of intracranial infection. Due to recent advances in genomic approaches, especially sequencing technologies, metagenomic next-generation sequencing (mNGS) has been applied in many research and clinical settings.

Case presentation

Here, we report a case of CNS infection with Acinetobacter baumannii in a 15-year-old woman, who previously underwent surgery for recurrence of ependymoma in the fourth ventricle. On the eleventh postoperative day, the patient had a high fever and leukocytosis in the cerebrospinal fluid (CSF). mNGS using CSF rapidly and accurately identified the causative pathogen as A. baumannii with carbapenem resistance genes blaOXA-23 and blaOXA-51, which were confirmed by subsequent culture and susceptibility tests within 5 days. During the disease, mNGS, culture, and drug susceptibility testing were continued to monitor changes in pathogenic bacteria and adjust medication. At present, there are no case reports on to the use of mNGS for detecting pathogens in postoperative infection with ependymoma and guide medication.

Conclusion

mNGS has great advantages in pathogen identification and even pathogen resistance prediction. Multiple mNGS examinations during the course of the disease play an important role in the dynamic monitoring of pathogens.

Prediction of Tissue Exposures of Meropenem, Colistin, and Sulbactam in Pediatrics Using Physiologically Based Pharmacokinetic Modeling

BACKGROUND

The combination of polymyxins, meropenem, and sulbactam demonstrated efficacy against multi-drug-resistant bacillus Acinetobacter baumannii. These three antibiotics are commonly used against major blood, skin, lung, and heart muscle infections.

OBJECTIVE

The objective of this study was to predict drug disposition and extrapolate the efficacy in these tissues using a physiologically based pharmacokinetic modeling approach that linked drug exposures to their target pharmacodynamic indices associated with antimicrobial activities against A. baumannii.

METHODS

An adult physiologically based pharmacokinetic model was developed for meropenem, colistin, and sulbactam and scaled to pediatrics accounting for both renal and non-renal clearances. The model reliability was evaluated by comparing simulated plasma and tissue drug exposures to observed data. Target pharmacodynamic indices were used to evaluate whether pediatric and adult dosing regimens provided sufficient coverage.

RESULTS

The modeled plasma drug exposures in adults and pediatric patients were consistent with reported literature data. The mean fold errors for meropenem, colistin, and sulbactam were in the range of 0.710-1.37, 0.981-1.47, and 0.647-1.39, respectively. Simulated exposures in the blood, skin, lung, and heart were consistent with reported penetration rates. In a virtual pediatric population aged from 2 to < 18 years, the interpretive breakpoints were achieved in 85-90% of subjects for their targeted pharmacodynamic indices after administration of pediatric dosing regimens consisting of 30 mg/kg of meropenem, and 40 mg/kg of sulbactam three times daily as a 3-h or continuous infusion and 5 mg/kg/day of colistin base activity.

CONCLUSIONS

The physiologically based pharmacokinetic modeling supports pediatric dosing regimens of meropenem/colistin/sulbactam in a co-administration setting against infections in the blood, lung, skin, and heart tissues due to A. baumannii.

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.

Systematic review on estimated rates of nephrotoxicity and neurotoxicity in patients treated with polymyxins

BACKGROUND

Nephrotoxicity and neurotoxicity are commonly associated with polymyxin treatment; however, the emergence of multidrug-resistant Gram-negative bacteria with limited therapeutic options has resulted in increased use of polymyxins.

OBJECTIVES

To determine the rates of nephrotoxicity and neurotoxicity during polymyxin treatment and whether any factors influence these.

DATA SOURCES

Medline, Embase and Cochrane Library databases were searched on 2 January 2020.

STUDY ELIGIBILITY CRITERIA

Studies reporting nephrotoxicity and/or neurotoxicity rates in patients with infections treated with polymyxins were included. Reviews, meta-analyses and reports not in English were excluded.

PARTICIPANTS

Patients hospitalized with infections treated with systemic or inhaled polymyxins were included. For comparative analyses, patients treated with non-polymyxin-based regimens were also included.

METHODS

Meta-analyses were performed using a random-effects model; subgroup meta-analyses were conducted where data permitted using a mixed-effects model.

RESULTS

In total, 237 reports of randomized controlled trials, cohort and case-control studies were eligible for inclusion; most were single-arm observational studies. Nephrotoxic events in 35,569 patients receiving polymyxins were analysed. Overall nephrotoxicity rate was 0.282 (95% confidence interval (CI) 0.259-0.307). When excluding studies where >50% of patients received inhaled-only polymyxin treatment or nephrotoxicity assessment was by methods other than internationally recognized criteria (RIFLE, KDIGO or AKIN), the nephrotoxicity rate was 0.391 (95% CI 0.364-0.419). The odds of nephrotoxicity were greater with polymyxin therapies compared to non-polymyxin-based regimens (odds ratio 2.23 (95% CI 1.58-3.15); p < 0.001). Meta-analyses showed a significant effect of polymyxin type, dose, patient age, number of concomitant nephrotoxins and use of diuretics, glycopeptides or vasopressors on the rate of nephrotoxicity. Polymyxin therapies were not associated with a significantly different rate of neurotoxicity than non-polymyxin-based regimens (p 0.051). The overall rate of neurotoxicity during polymyxin therapy was 0.030 (95% CI 0.020-0.043).

CONCLUSIONS

Polymyxins are associated with a higher risk of nephrotoxicity than non-polymyxin-based regimens.

Use of Intraventricular Medications in Critically Ill Patients: A Systematic Review

New evidence and increased use of intracranial devices have increased the frequency of intraventricular (IVT) medication administration in the neurologic intensive care unit. Significant benefits and risks are associated with administration of medications directly into the central nervous system. This review summarizes important literature, along with key information for clinicians regarding the administration, dosing, monitoring, and adverse effects related to IVT medication usage. Multiple medications have supporting literature for their use in critically ill patients including amphotericin B, aminoglycosides, colistimethate, daptomycin, quinupristin/dalfopristin, vancomycin, alteplase, and nicardipine. Sterile preparation and delivery, along with different types of devices that support medication administration, are also reviewed. One randomized, placebo-controlled trial of alteplase demonstrated decreased mortality but no change in good functional outcome. Other reports of IVT medication use are mainly limited to case reports and retrospective case series. There is a need for increased research on the topic; however, several practical barriers decrease the likelihood of a large, placebo-controlled, prospective study for most indications. Providers should consider implementing protocols to maximize safety of IVT medication delivery to ensure optimal patient outcomes.

Intraventricular Tigecycline as a Last Resort Therapy in a Patient with Difficult-to-Treat Healthcare-Associated Acinetobacter baumannii Ventriculitis: a Case Report

Healthcare-associated ventriculitis and meningitis is a common complication in patients who suffer from head trauma or have undergone a neurosurgery. Healthcare-associated ventriculitis and meningitis is associated with significant morbidity and mortality. Complications of healthcare-associated ventriculitis and meningitis include persistent vegetative state, moderate and severe disability, and death. Acinetobacter baumannii is the causative pathogen in 3.6–11.2% of cases of healthcare-associated ventriculitis and meningitis. Cases of difficult-to-treat healthcare-associated A. baumannii ventriculitis and meningitis are being reported more frequently. However, in most of these cases, a combination of intravenous (IV) and intraventricular (IVT)/intrathecal colistin achieves good therapeutic outcome. This report describes a clinical case of difficult-to-treat healthcare-associated A. baumannii ventriculitis. The A. baumannii strain was sensitive to colistin and trimethoprim-sulfamethoxazole, intermediate to tigecycline, and resistant to other antibiotics. While colistin was the drug of choice in our case, the patient developed anaphylactoid reaction during the IV administration of the loading dose of colistin, which mandated us to discontinue colistin and complicated the treatment of our patient. The patient did not respond to a combination of IV antibiotics that included meropenem, trimethoprim-sulfamethoxazole, and tigecycline. However, when IVT tigecycline was added as a last-resort therapeutic option, the patient’s ventriculitis dramatically improved, and the patient was discharged from the hospital. Physicians who treat patients with healthcare-associated A. baumannii ventriculitis might resort to IVT tigecycline when they run out of therapeutic options.

International Consensus Guidelines for the Optimal Use of the Polymyxins: Endorsed by the American College of Clinical Pharmacy (ACCP), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), Infectious Diseases Society of America (IDSA), International Society for Anti-infective Pharmacology (ISAP), Society of Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP)

The polymyxin antibiotics colistin (polymyxin E) and polymyxin B became available in the 1950s and thus did not undergo contemporary drug development procedures. Their clinical use has recently resurged, assuming an important role as salvage therapy for otherwise untreatable gram-negative infections. Since their reintroduction into the clinic, significant confusion remains due to the existence of several different conventions used to describe doses of the polymyxins, differences in their formulations, outdated product information, and uncertainties about susceptibility testing that has led to lack of clarity on how to optimally utilize and dose colistin and polymyxin B. We report consensus therapeutic guidelines for agent selection and dosing of the polymyxin antibiotics for optimal use in adult patients, as endorsed by the American College of Clinical Pharmacy (ACCP), Infectious Diseases Society of America (IDSA), International Society of Anti-Infective Pharmacology (ISAP), Society for Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP). The European Society for Clinical Microbiology and Infectious Diseases (ESCMID) endorses this document as a consensus statement. The overall conclusions in the document are endorsed by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). We established a diverse international expert panel to make therapeutic recommendations regarding the pharmacokinetic and pharmacodynamic properties of the drugs and pharmacokinetic targets, polymyxin agent selection, dosing, dosage adjustment and monitoring of colistin and polymyxin B, use of polymyxin-based combination therapy, intrathecal therapy, inhalation therapy, toxicity, and prevention of renal failure. The treatment guidelines provide the first ever consensus recommendations for colistin and polymyxin B therapy that are intended to guide optimal clinical use.

Local complications of adjunct intrathecal antibiotics for nosocomial meningitis associated with gram-negative pathogens: a meta-analysis

Direct delivery of antibiotics to the ventricular system offers an alternative for the management of nosocomial meningitis. However, the available literature frequently results in controversial findings regarding its safety. The present meta-analysis aimed at summarizing the risk of local complications after the administration of intraventricular/intrathecal (IVT/IT) antibiotics for the treatment of ventriculitis/meningitis (VM) associated with gram-negative pathogens. We systematically searched the medical literature from 1964 until July 2018, for clinical studies reporting on complications after the index treatment. The quality of the eligible studies was classified as "high," "moderated," and "low" for randomized controlled trials, observational studies, and case series, respectively. The results were summarized as pooled frequencies, estimated by the random- or fixed-effects models, according to the inter-study heterogeneity. The publication bias was visualized in trim-and-fill funnel plots. Τhe analysis included twenty-three primary studies with 229 patients. The overall complication rate was as high as 0.13 (95% CI 0.08; 0.19, I² = 9%); chemical meningitis and seizures represented the majority of the complications, with an occurrence rate of 0.11 (95% CI 0.07; 0.17, I² = 0%) and 0.07 (95% CI 0.04; 0.12; I² = 0%), respectively. The meta-analysis was based on studies of "moderate" and "low" reporting quality, while the publication bias after inspecting of the funnel plots revealed significant asymmetry. The present review denotes the absence of large, high-quality studies in the field. Nevertheless, IVT/IT was associated with moderate morbidity, mainly attributed to chemical meningitis and seizures. Further high-quality studies are still required before this therapeutic modality becomes broadly established.

Intrathecal or intraventricular antimicrobial therapy for post-neurosurgical intracranial infection due to multidrug-resistant and extensively drug-resistant Gram-negative bacteria: A systematic review and meta-analysis

This review investigated the effectiveness and safety of intrathecal (ITH) or intraventricular (IVT) antimicrobial therapy for post-neurosurgical intracranial infection due to multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria. Electronic databases including PubMed, EMBASE and the Cochrane Library databases were searched for clinical studies that compared the addition of ITH/IVT therapy with intravenous (IV) monotherapy in the treatment of post-neurosurgical intracranial infection due to MDR/XDR Gram-negative bacteria. Eligible articles were analysed using Stata/SE software v.12.0. Publication bias was assessed using Begg's funnel plot and Egger's test. Nine studies involving 296 patients were included. The odds ratio (OR) for death (IV+ITH/IVT versus IV) reported in the included studies ranged from 0.02-0.93. The overall pooled OR was 0.15 [95% confidence interval (CI) 0.08-0.28; P < 0.001] and the risk of mortality was significantly different between the two groups. Microbiological clearance was significantly different between the two groups, with a pooled OR of 0.02 (95% CI 0.01-0.10; P < 0.001). In observational studies, addition of ITH/IVT antimicrobial therapy is associated with a lower risk of mortality and a higher microbiological clearance rate, with mild adverse effects, in patients with post-neurosurgical intracranial infection due to MDR/XDR Gram-negative bacteria. A well-designed randomised controlled trial is necessary to address this important issue.

Managing Meningoencephalitis in Indian ICU

How to cite this article: Sapra H, Singhal V. Managing Meningo-encephalitis in Indian ICU. Indian J Crit Care Med 2019;23(Suppl 2):S124-S128.

Polymyxin Acute Kidney Injury: Dosing and Other Strategies to Reduce Toxicity

Polymyxins are valuable antimicrobials for the management of multidrug-resistant Gram-negative bacteria; however, nephrotoxicity associated with these drugs is a very common side effect that occurs during treatment. This article briefly reviews nephrotoxic mechanisms and risk factors for polymyxin-associated acute kidney injury (AKI) and discusses dosing strategies that may mitigate kidney damage without compromising antimicrobial activity. Polymyxins have a very narrow therapeutic window and patients requiring treatment with these drugs are frequently severely ill and have multiple comorbidities, which increases the risk of AKI. Notably, there is a significant overlap between therapeutic and toxic plasma polymyxin concentrations that substantially complicates dose selection. Recent dosing protocols for both colistin and polymyxin B have been developed and may help fine tune dose adjustment of these antibiotics. Minimizing exposure to modifiable risk factors, such as other nephrotoxic agents, is strongly recommended. The dose should be carefully selected, particularly in high-risk patients. The administration of oxidative stress-reducing drugs is a promising strategy to ameliorate polymyxin-associated AKI, but still requires support from clinical studies.

Combination Treatment with Intravenous Tigecycline and Intraventricular and Intravenous Colistin in Postoperative Ventriculitis Caused by Multidrug-resistant Acinetobacter baumannii

Nosocomial infections with multidrug-resistant (MDR) pathogens are a life-threatening complication in neurosurgery. An MDR Acinetobacter baumannii (A. baumannii) central nervous system (CNS) infection following neurosurgery has been previously reported and was treated with relative success using intraventricular and/or intravenous (IV) colistin, IV tigecycline, or IV colistin-rifampicin combination therapy. We present a case of MDR A. baumannii in a 13-year-old girl following parietal craniotomy for the resection of a right intraventricular meningioma. Several days after surgery, the patient presented with clinical, radiological, laboratorial, and microbiological evidence of carbapenem-resistant A. baumannii ventriculitis. She was treated with IV colistin and then with combined intraventricular-IV colistin, with partial failure. The combined treatment of IV tigecycline and associated intraventricular and intravenous colistin was started and significant improvement was seen clinically and radiologically, with negative cultures after one week. To the best of our knowledge, this is the first case of a successful combination of intraventricular and IV colistin combined with IV tigecycline after a partial treatment failure with intraventricular and IV colistin alone.

Clinical Pharmacokinetics, Pharmacodynamics and Toxicodynamics of Polymyxins: Implications for Therapeutic Use

The availability of sensitive, accurate and specific analytical methods for the measurement of polymyxins in biological fluids has enabled an understanding of the pharmacokinetics of these important antibiotics in healthy humans and patients. Colistin is administered as its inactive prodrug colistin methanesulfonate (CMS) and has especially complex pharmacokinetics. CMS undergoes conversion in vivo to the active entity colistin, but the rate of conversion varies from brand to brand and possibly from batch to batch. The extent of conversion is generally quite low and depends on the relative magnitudes of the conversion clearance and other clearance pathways for CMS of which renal excretion is a major component. Formed colistin in the systemic circulation undergoes very extensive tubular reabsorption; the same mechanism operates for polymyxin B which is administered in its active form. The extensive renal tubular reabsorption undoubtedly contributes to the propensity for the polymyxins to cause nephrotoxicity. While there are some aspects of pharmacokinetic behaviour that are similar between the two clinically used polymyxins, there are also substantial differences. In this chapter, the pharmacokinetics of colistin, administered as CMS, and polymyxin B are reviewed, and the therapeutic implications are discussed.

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.

Persistent Gram-negative Neurosurgical Meningitis in a Neonate, Successfully Treated With Intraventricular Colistin: Case Report and Review of the Literature

We present a case of Gram-negative neurosurgical meningitis in a neonate, refractory to optimal intravenous therapy and removal of ventriculoperitoneal shunt. Cerebrospinal fluid was sterilized within 24 hours using intraventricular colistin. This is the first report of intraventricular colistin use in neonatal meningitis caused by Enterobacter cloacae.

Efficacy of intravenous plus intrathecal/intracerebral ventricle injection of polymyxin B for post-neurosurgical intracranial infections due to MDR/XDR Acinectobacter baumannii: a retrospective cohort study

Background

Post-neurosurgical intracranial infections caused by multidrug-resistant or extensively drug-resistant Acinetobacter baumannii are difficult to treat and associated with high mortality. In this study, we analyzed the therapeutic efficacy of intravenous combined with intrathecal/intracerebral ventricle injection of polymyxin B for this type of intracranial infection.

Methods

This retrospective study was conducted from January 2013 to September 2017 at the Second Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou,China) and included 61 cases for which cerebrospinal fluid (CSF) cultures were positive for multidrug-resistant or extensively drug-resistant A. baumannii after a neurosurgical operation. Patients treated with intravenous and intrathecal/intracerebral ventricle injection of polymyxin B were assigned to the intrathecal/intracerebral group, and patients treated with other antibiotics without intrathecal/intracerebral injection were assigned to the intravenous group. Data for general information, treatment history, and the results of routine tests and biochemistry indicators in CSF, clinical efficiency, microbiological clearance rate, and the 28-day mortality were collected and analyzed.

Results

The rate of multidrug-resistant or extensively drug-resistant A. baumannii infection among patients who experienced an intracranial infection after a neurosurgical operation was 33.64% in our hospital. The isolated A. baumannii were resistant to various antibiotics, and most seriously to carbapenems (100.00% resistance rate to imipenem and meropenem), cephalosporins (resistance rates of 98.38% to cefazolin, 100.00% to ceftazidime, 100.00% to cefatriaxone, and 98.39% to cefepime). However, the isolated A. baumannii were completely sensitive to polymyxin B (sensitivity rate of 100.00%), followed by tigecycline (60.66%) and amikacin (49.18%). No significant differences in basic clinical data were observed between the two groups. Compared with the intravenous group, the intrathecal/intracerebral group had a significantly lower 28-day mortality (55.26% vs. 8.70%, P = 0.01) and higher rates of clinical efficacy and microbiological clearance (95.65% vs. 23.68%, P < 0.001; 91.30% vs. 18.42%, P < 0.001, respectively).

Conclusions

Intravenous plus intrathecal/intracerebral ventricle injection of polymyxin B is an effective regimen for treating intracranial infections caused by multidrug-resistant or extensively drug-resistant A. baumannii.

Outcomes of adjunctive therapy with intrathecal or intraventricular administration of colistin for post-neurosurgical meningitis and ventriculitis due to carbapenem-resistant acinetobacter baumannii

The efficacy and safety of intrathecal (ITH) or intraventricular (IVT) colistin in addition to intravenous (IV) colistin for meningitis and ventriculitis due to carbapenem-resistant Acinetobacter baumannii (CRAB) is unclear. In this retrospective observational study of 40 patients with post-neurosurgical meningitis and ventriculitis due to CRAB, 33 patients without concomitant infection received appropriate dosage regimens of IV colistin. Of the 33 patients, 17 received additional ITH/IVT colistin and 16 received only IV colistin. The 14-day, 30-day and in-hospital mortality rates were nominally lower for patients who received ITH/IVT colistin adjunctive therapy versus patients who received only IV colistin (24% vs. 38%, 29% vs. 56% and 29% vs. 56%, respectively). The costs of treatment were significantly lower, the lengths of hospital and intensive care unit (ICU) stay were significantly shorter, and the number of ventilator days was significantly less among patients who received ITH/IVT colistin compared with patients who did not receive ITH/IVT colistin. The initial Acute Physiology and Chronic Health Evaluation (APACHE) II and Glasgow Coma Scale (GCS) scores were associated with 30-day mortality with odds ratios (95% confidence intervals) of 1.21 (1.08-1.46) and 0.77 (0.44-0.85), respectively. Chemical meningitis from ITH/IVT colistin was mild and resolved spontaneously. Treatment of post-neurosurgical CRAB meningitis and ventriculitis with ITH/IVT colistin as an adjunct to IV colistin was associated with shorter lengths of hospital and ICU stay and a trend to lower mortality, especially among severely ill patients.

The 21st-century challenge to neurocritical care: the rise of the superbug Acinetobacter baumannii. A meta-analysis of the role of intrathecal or intraventricular antimicrobial therapy in reduction of mortality

OBJECTIVE

Neurosurgical infections due to multidrug-resistant organisms have become a nightmare that neurosurgeons are facing in the 21st century. This is the dawn of the so-called postantibiotic era. There is an urgent need to review and evaluate ways to reduce the high mortality rates due to these infections. The present study evaluates the efficacy of combined intravenous plus intrathecal or intraventricular (IV + IT) therapy versus only intravenous (IV) therapy in treating postneurosurgical Acinetobacter baumannii infections.

METHODS

The authors performed a meta-analysis of all peer-reviewed studies from the PubMed, Cochrane Library database, ScienceDirect, and EMBASE in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Five studies were finally included in the present analysis: 126 patients were studied who had postneurosurgical A. baumannii infection. The Cochrane collaboration tool was used to evaluate risk of bias, and a test of heterogeneity was performed. The I2 statistic was calculated. The patients were divided into 2 groups: the IV group received only intravenous therapy and the IV + IT group received both intravenous and intrathecal or intraventricular antimicrobial therapy. The outcome was mortality attributed specifically to A. baumannii infection in postneurosurgical cases. The pooled data were analyzed using the Cochran-Mantel-Haenszel method in a fixed-effects model.

RESULTS

The total number of patients in the IV-only group was 73, and the number of patients in the IV + IT group was 53. The mean duration of intravenous therapy was 27 days. The mean duration of intrathecal colistin was 21 days. The intravenous dose of colistin ranged from 3.75 to 8.8 MIU per day. The dose of intrathecal colistin ranged between 125,000 and 250,000 IU per day. The overall calculated odds ratio for mortality for the IV + IT group after pooling the data was 0.16 (95% CI 0.06–0.40, p < 0.0001). The patients who received IV + IT therapy had an 84% lower risk of dying due to the infection compared with those who received only IV therapy.

CONCLUSIONS

There is an 84% lower risk of mortality in patients who have been treated with combined intrathecal or intraventricular plus intravenous antimicrobial therapy versus those who have been treated with intravenous therapy alone. The intrathecal or intraventricular route should be strongly considered when dealing with postneurosurgical multidrug-resistant A. baumannii infections.

Therapeutic drug monitoring for colistin therapy in severe multi-resistant Acinetobacter intracerebral abscess: A single case study with high-dose colistin and review of literature

Objectives:

Intracranial infections due to multidrug- resistant (MDR) gram-negative pathogens are associated with increased morbidity and mortality. As therapeutic options are limited and systemic drug penetration into the infection focus is difficult, intraventricular therapy has been described.

Methods:

We report on a patient with intracranial abscess caused by MDR Acinetobacter baumannii.

Results:

He was treated with high doses of intravenous and intraventricular colistin resulting in microbiological clearance and clinical cure. Therapy was controlled by therapeutic drug monitoring (TDM) of serum and liquor colistin levels. About 100 cases with intraventricular or intrathecal colistin are reported in literature but data on TDM are sparse.

Conclusions:

This is one of the first cases providing data on TDM for locally administered high dose colistin therapy for the treatment of intracranial abscess formations. Based on these findings, increasing the intraventricular application interval paralleled with intravenous colistin could possibly be sufficient to achieve appropriate therapeutic drug levels. Further studies are needed to support alternative dosing strategies in similar cases.

Clinical characteristics, microbiology and outcomes of external ventricular drainage-associated infections: The importance of active treatment

Data concerning clinical characteristics, microbiology, treatment and outcomes of external ventricular drainage-associated infections (EVDAI) are limited. All hospitalized patients with EVDAI in a University Hospital between January 2009 and December 2015 were retrospective recorded. Only the first episode per patient was included. An antibiotic was considered "active" when its pharmacokinetic properties were appropriate for EVDAI and the implicated microorganism was in vitro susceptible. During the 7-year study period, 36 EVDAI were identified. Median patient age was 53years and 23 (63.9%) were male. Catheter types were intraventricular (70.6%) and lumbar (29.4%). Median catheterization duration before infection was 14days. Gram-negative bacteria (GNB) predominated (57.9%), followed by gram-positives (36.8%) and fungi (5.3%). Administered antibiotics were considered "active" in 69.4% of empirical and in 86.1% of definitive treatment regimens. In 10 infections, intraventricular/intrathecal (IVT) antibiotics were administered. Eleven patients died (30.6%) during hospitalization. Patients who died had higher rates of EVDAI by GNB (p=0.011) and higher rates of treatment with intravenous colistin (p=0.019 for empirical and p=0.006 for definitive colistin). Compared to EVDAI by other pathogens, patients with EVDAI by GNB had longer catheter-days before infection (p<0.001) and higher mortality (p=0.011). In our study, GNB were a frequent cause of EVDAI, and were related with high rates of inactive treatment and mortality. Intravenous colistin alone is not effective and treatment should include IVT antibiotics and intravenous antibiotics that achieve adequate CSF levels.

Variables determining mortality in patients with Acinetobacter baumannii meningitis/ventriculitis treated with intrathecal colistin

AIM

To examine the variables associated with mortality in patients with Acinetobacter baumannii-related central nervous system infections treated with intrathecal colistin.

MATERIALS AND METHODS

This multi-centre retrospective case control study included patients from 11 centres in Turkey, as well as cases found during a literature review. Only patients with CNS infections caused by multidrug-resistant or extensively drug-resistant Acinetobacter baumannii treated with intrathecal colistin were included in this study. The variables associated with mortality were determined by dividing the patients into groups who died or survived during hospitalisation, and who died or survived from Acinetobacter meningitis.

RESULTS

Among the 77 cases enrolled in the study, 35 were found through a literature review and 42 were cases from our centres. Forty-four cases (57.1%) were male and the median age was 48 years (range: 20-78 years). Thirty-seven patients (48%) died during hospitalisation. The variables associated with increased all-cause mortality during hospitalisation included old age (odds ratio, 1.035; 95% confidence interval (CI), 1.004-1.067; p=0.026) and failure to provide cerebrospinal fluid sterilisation (odds ratio, 0.264; 95% confidence interval, 0.097-0.724; p=0.01). There is a trend (P=0.062) towards higher mortality with using of meropenem during meningitis treatment. Fifteen cases (19%) died from meningitis. There were no significant predictors of meningitis-related mortality.

CONCLUSIONS

The mortality rate for central nervous system infections caused by multidrug-resistant or extensively drug-resistant Acinetobacter baumannii is high. Old age and failure to provide CSF sterilisation are associated with increased mortality during hospitalisation.

Colistin loading dose: evaluation of the published pharmacokinetic and clinical data

Colistin (polymyxin E) has been widely used since the beginning of the century as a last-option antibiotic for the treatment of patients with multidrug-resistant and extensively-drug resistant bacterial infections. However, colistin dosing is troublesome because each batch of the drug contains a mixture of components and because it is administered as the inactive pro-drug colistimethate sodium (CMS), which has different pharmacokinetic (PK) properties from the active drug. Significant inter-individual and intra-individual variability in colistin plasma concentrations have been observed in all available studies. Low plasma concentrations of the drug during the first hours from initiation of administration suggested that a loading dose would be appropriate. However, other PK studies challenge this approach. Clinical data from randomised controlled trials are not available, whilst data from observational studies do not support higher effectiveness of a loading dose. In this review, we summarise the available data regarding the administration of a loading dose and discuss the issues surrounding the potential advantages and disadvantages as well as the context within which such an approach could be beneficial to patients.