Silver-impregnated external-ventricular-drain-related cerebrospinal fluid infections: a meta-analysis

External ventricular drainage in pediatric patients: indications, management, and shunt conversion rates

PURPOSE

Placement of an external ventricular drainage (EVD) is one of the most frequent procedures in neurosurgery, but it has specific challenges and risks in the pediatric population. We here investigate the indications, management, and shunt conversion rates of an EVD.

METHODS

We retrospectively analyzed the data of a consecutive series of pediatric patients who had an EVD placement in the Department of Neurosurgery at Hannover Medical School over a 12-year period. A bundle approach was introduced to reduce infections. Patients were categorized according to the underlying pathology in three groups: tumor, hemorrhage, and infection.

RESULTS

A total of 126 patients were included in this study. Seventy-two were male, and 54 were female. The mean age at the time of EVD placement was 5.2 ± 5.0 years (range 0-17 years). The largest subgroup was the tumor group (n = 54, 42.9%), followed by the infection group (n = 47, 37.3%), including shunt infection (n = 36), infected Rickham reservoir (n = 4), and bacterial or viral cerebral infection (n = 7), and the hemorrhage group (n = 25, 19.8%). The overall complication rate was 19.8% (n = 25/126), and the total number of complications was 30. Complications during EVD placement were noted in 5/126 (4%) instances. Complications during drainage time were infection in 9.5% (12 patients), dysfunction in 7.1% (9 patients), and EVD dislocation in 3.2% (4 patients). The highest rate of complications was seen in the hemorrhage group. There were no long-term complications. Conversion rates into a permanent shunt system were 100% in previously shunt-dependent patients. Conversion rates were comparable in the tumor group (27.7%) and in the hemorrhage group (32.0%).

CONCLUSION

EVD placement in children is an overall safe and effective option in children. In order to make further progress, carefully planned prospective and if possible randomized studies are needed controlling for multivariable aspects.

External ventriculostomy-associated infection reduction after updating a care bundle

BACKGROUND

Despite the clinical benefits of external ventricular drains (EVD), these devices can lead to EVD-related infections (EVDRI). The drainage insertion technique and standardized guidelines can significantly reduce the risk of infection, mainly caused by gram-positive bacteria. However, gram-negative microorganisms are the most frequent causative microorganisms of EVDRI in our hospital. We aimed to determine whether a new bundle of measures for the insertion and maintenance of a drain could reduce the incidence of EVDRI. This cohort study of consecutive patients requiring EVD from 01/01/2015 to 12/31/2018 compared the patients' characteristics before and after introducing an updated protocol (UP) for EVD insertion and maintenance in 2017.

RESULTS

From 204 consecutive patients, 198 requiring EVD insertion were included (54% females, mean age 55 ± 15 years). The before-UP protocol included 87 patients, and the after-UP protocol included 111 patients. Subarachnoid (42%) and intracerebral (24%) hemorrhage were the main diagnoses at admission. The incidence of EVDRI fell from 13.4 to 2.5 episodes per 1000 days of catheter use. Gram-negative bacteria were the most frequent causative microorganisms. Previous craniotomy remained the only independent risk factor for EVDRI. EVDRI patients had increased mechanical ventilation durations, hospital and ICU stays, and percutaneous tracheostomy requirements.

CONCLUSIONS

A care bundle focusing on fewer catheter sampling and more accurate antiseptic measures can significantly decrease the incidence of EVDRI. After implementing the management protocol, a decreased incidence of infections caused by gram-negative and gram-positive bacteria and reduced ICU and hospital lengths of stay were observed.

Prevention of Ventriculostomy Related Infection: Effectiveness of Impregnated Biomaterial

External ventricular drain(EVD) exposes the patient to infectious complications which are associated with significant morbidity and economic burden. Biomaterials impregnated with various antimicrobial agents have been developed to decrease the rate of bacterial colonization and subsequent infection. While promising, antibiotics and silver-impregnated EVD showed conflicting clinical results. The aim of the present review is to discuss the challenges associated with the development of antimicrobial EVD catheters and their effectiveness from the bench to the bedside.

Bacterial Meningitis among Intracranial Surgery Patients at a University Hospital in Northern India

Background

Cerebrospinal infections are the cause of poor prognosis among post-neurosurgery patients owing to delay in improvement of neurological functions, leading to increased length of hospital stay, proceeding to disability or death.

Methods and materials

This retrospective observational study was performed at a tertiary care center in Northern India, where all patients with bacterial cerebrospinal infections from July 2019 to July 2022 were evaluated for post-neurosurgery cerebrospinal shunt infections, and all demographic data and risk factors were extracted from the hospital information system (HIS).

Results

The study includes 150 (150/1986, 7.55%) culture-confirmed cases of bacterial meningitis out of 1986 cases of suspected bacterial meningitis patients. Ninety-six (96/150, 64.0%) post-neurosurgery patients with cerebrospinal fluid (CSF) leaks were managed using external ventricular drain (EVD) or ventriculoperitoneal (VP) shunt. Seventy-four (74/96, 77.08%) patients were managed only on EVD, whereas 22 (22/96, 22.92%) patients were managed only on VP shunt. Eighty-two (82/96, 85.4%) multidrug-resistant microorganisms (MDROs) were isolated and 70 (70/82, 85.36%) were gram-negative bacteria, of which 56 (56/74, 75.68%) gram-negative bacteria showed extended-spectrum beta-lactamase (ESBL)-producing character in those with an EVD, 14 (14/22, 63.63%) with a VP shunt. Among gram-negative bacteria, Acinetobacter baumannii showed high rates of resistance: 21 (21/23, 91.30%) and 8 (8/8, 100%) were ESBL-producing A. baumannii in patients managed on EVD and VP shunt, respectively.

Conclusion

This study determines the risk factors, the spectrum of pathogenic microorganisms, multidrug resistance, and the nature of intracranial lesions isolated among the patients who developed bacterial cerebrospinal infections in post-neurosurgery patients.

How to cite this article

Kar M, Jamwal A, Dubey A, Sahu C, Patel SS. Bacterial Meningitis among Intracranial Surgery Patients at a University Hospital in Northern India. Indian J Crit Care Med 2022;26(12):1244-1252.

Cerebrospinal fluid white cell count to red cell count ratio as a predictor of ventriculitis in patients with external ventricular drains

INTRODUCTION

External ventricular drain (EVD) associated ventriculitis is a complication of EVD placement associated with significant morbidity and mortality. Gold-standard for EVD associated bacterial ventriculitis diagnosis involves cerebrospinal fluid (CSF) sampling from the EVD with microscopy, culture and sensitivity testing. The ratio of white blood cells to red blood cells has anecdotally been considered a predictive factor in diagnosing EVD associated ventriculitis, however no study has been done demonstrating this.

METHODS

A retrospective cross-sectional study was designed to assess whether the ratio of CSF white blood cells to red blood cells could be used to diagnose EVD associated ventriculitis. Data was collected for all patients undergoing EVD insertion at a major neurosurgical unit in Sydney, Australia. A receiver operator characteristics (ROC) curve was used to determine if this ratio was useful, and Youden's index was calculated to determine the appropriate cut-off point.

RESULTS

This sample of n = 157 consecutive patients a total of 29 patients were diagnosed with ventriculitis. The area under the ROC curve was significant (0.706, P <0.001), and Youden's index demonstrated an appropriate cut-off point was a ratio of 1:106.

DISCUSSION

CSF parameters have long been considered predictive of EVD associated ventriculitis. We demonstrated that using a component of routine testing it is possible to accurately predict a ventriculitis diagnosis. As the ratio is used, it enables discrimination in a raised white blood cell count due to local trauma with interventricular bleeding.

CONCLUSION

CSF white blood cell to red blood cell ratio is an appropriate diagnostic test for ventriculitis.

The Use of Intraventricular Instillation of Vancomycin to Prevent External Ventricular Drainage Related Infection: A Clinical Prospective Study

BACKGROUND

External ventricular drainage (EVD)-related infection (ERI) represents an important condition with potential high morbidity with significant impact on patient outcomes. Prophylactic systemic antibiotics are routinely administered to patients with EVD, but they do not significantly lower the incidence of ERIs. Intraventricular treatment with vancomycin appeared to be safe and effective, but most reports are case-reports/-series and retrospective studies.

METHODS

A prospective non-randomized case-control study was conducted in a consecutive series of 116 patients treated with EVD insertion. The study includes the group of patients treated with intrathecal vancomycin (Group A, 62 patients) compared with the control group treated with daily intravenous cefazolin (Group B, 54 patients).

RESULTS

No statistically significant differences were found between the 2 groups with regard to the duration of catheterization and occurrence of ERI during hospitalization. EVD was replaced in 16 cases (25.8%) in group A and in 12 cases (22.2%) in the control group B (P 0.67). Three cases (4.8%) of ERI have been found in group A and 5 (9.3%) in the control group (P = 0.34). All reported cases of infection in group A were caused by gram-negative agents; on the opposite, cases of infections in the control group B were caused above all by gram-positive bacteria with a statistical difference (P = 0.03).

CONCLUSIONS

In this first prospective study on this topic, we found that intrathecal Vancomycin administration in EVDs does not reduce the occurrence of ERI compared with intravenous cefazolin prophylaxis, but induces selection of gram-negative bacteria.

Healthcare-associated central nervous system infections

PURPOSE OF REVIEW

The aim of this review is to provide a practical and updated summary on healthcare-associated central nervous system infections and their management.

RECENT FINDINGS

The term 'healthcare-associated ventriculitis and meningitis' has recently been coined and clinical practical guidelines have been published on the management of these nosocomial infections. Many aspects have still to be further investigated (e.g. cerebrospinal fluid biomarkers, indications for novel antibiotics, intrathecal antimicrobial regimens).

SUMMARY

Clinicians should maintain a high index of suspicion for healthcare-associated central nervous system infections in patients with specific risk factors (i.e. recent neurosurgery, cerebrospinal shunts, drains or implantable devices, head/spinal traumatic events), taking into account systemic signs, and alterations in microbiological, imaging, cerebrospinal fluid findings. The diagnosis is often difficult to confirm because of reduced levels of consciousness or coma. Both Gram-positive and Gram-negative (often multidrug-resistant or even pandrug-resistant) microorganisms may be the cause. Selection of antibiotics must consider susceptibility and penetration into the central nervous system. Ineffective treatments are frequent, and mortality can reach 60%. Future research should focus on the diagnostic performance of biomarkers and on the use of novel antimicrobial regimens, especially for the treatment of difficult to treat infections.

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.

Effect of External Ventricular Drain Tunnel Length on Cerebrospinal Fluid Infection Rates-A Bayesian Network Meta-Analysis

BACKGROUND

External ventricular drain (EVD)-associated cerebrospinal fluid infection (EACI) remains a major complication associated with EVD. Length of EVD tunnel, an overlooked but modifiable factor, can be associated with increased risk of EACI. The aim of this study is to find the tunnel length associated with least chances of EACI by performing a network meta-analysis.

METHODS

A comprehensive search of different databases was performed to retrieve studies that studied the rates of EACI with different EVD tunnel lengths and a Bayesian network meta-analysis was performed.

RESULTS

Six studies met the inclusion criteria and were included in the network meta-analysis. With 0 cm tunnel length as reference, the odds ratio (OR) for developing EACI was minimum for tunnel length 5-10 cm (OR, 0.027). It was followed by tunnel length of 5 cm (OR, 0.060) and 10 cm (OR, 0.075). The surface under the cumulative ranking curve plot showed that the probability of the tunnel length 5-10 cm (ranked first), 5 cm (ranked second), and 10 cm (ranked third) for being the best EVD tunnel length was found to be 86%, 64%, and 61%, respectively.

CONCLUSIONS

The length for which an EVD is tunneled may have an impact on the rate of EACI. Our network meta-analyses showed that the tunnel length of 5-10 cm was associated with the lowest rates of EACI, with 86% probability of being the best EVD tunnel length. The probability of a patient with 5-10 cm EVD length developing EACI was 2.7% compared with zero tunnel length.

Comparison of a bolt-connected external ventricular drain with a tunneled external ventricular drain - a narrative review and meta-analysis

External ventricular drain (EVD) is one of the most commonly performed neurosurgical procedures. EVD can be associated with high rates of complications like misplacement, iatrogenic hemorrhage, and CSF infection. Several modifications have been proposed in the EVD insertion techniques to decrease the risk of these complications. Bolt-connected EVD, one of these modifications which involves insertion of a bolt in the burr hole, has been proposed to have better chances of optimal placement of EVD tip, lesser risk of CSF infection, and accidental pullout. A comprehensive search of different databases was performed to retrieve studies comparing the bolt-connected EVD with tunneled EVD and meta-analysis was done. Seven studies met inclusion criteria and were included in the meta-analysis. Our analysis revealed that bolt-connected EVD is associated with significantly better chances of optimal placement than traditional tunneled EVD (MH OR-1.65, 95% CI 1.14 to 2.40, p = 0.008). We also observed that bolt-connected EVD is associated with significantly decreased risk of CSF infection (MH OR-0.60, 95% CI 0.39 to 0.94, p = 0.026), EVD malfunction (MH OR-0.31, 95% CI 0.16 to 0.58, p = 0.0003), and accidental disconnection (MH OR-0.09, 95% CI 0.03 to 0.26, p < 0.0001) as compared to traditional tunneled EVD. The difference between the two techniques was not statistically significant for complications, multiple punctures done for insertion of EVD, iatrogenic intracranial, and need of reoperation. Bolt-connected external ventricular drain is associated with significantly more chances of optimal placement and lesser chances of accidental discontinuation and CSF infection than tunneled EVD. There was no statistically significant difference noted between the two techniques for multiple punctures done for insertion of EVD, iatrogenic intracranial hemorrhage and need of reoperation. However, most of the included studies were retrospective. Thus, the results from the meta-analysis should be interpreted with caution as further prospective high-quality studies are needed.

Chlorhexidine dressings could reduce external ventricular drain infections: results from a systematic review and meta-analysis

BACKGROUND

The incidence of external ventricular drain (EVD) infections remains high. Chlorhexidine dressings have demonstrated efficacy in reducing infections associated with indwelling catheters at other body sites, although evidence for their use with EVDs is limited.

AIM

The aim of this systematic review and meta-analysis was to evaluate the efficacy of chlorhexidine dressings in reducing EVD associated cerebrospinal fluid infection (EVDAI).

METHODS

Systematic review and meta-analysis. MEDLINE, EMBASE and the Cochrane library were queried for articles from inception. The primary outcome was the incidence of EVDAI. Secondary outcomes included device safety, microbiological outcomes and shunt-dependency.

FINDINGS

From 896 unique records, 5 studies were included of which 4 presented suitable data for quantitative analysis including 3 case series and one underpowered randomised controlled trial. There was a high risk of bias in all studies. 880 patients were included with a mean age of 57.7 years (95% CI 57.4-58.0 years). In primary outcome analysis, the chlorhexidine dressing group had a significantly lower incidence of EVDAI (1.7% vs. 7.9%, RD = 0.07, 95% CI 0.00 - 0.13, p = 0.04).

CONCLUSION

Chlorhexidine dressings may reduce the incidence of EVDAI but require future study in randomised trials to definitively determine efficacy.

Efficacy of antimicrobial medicated ventricular catheters: a network meta-analysis with trial sequential analysis

There is paucity of evidence regarding relative performance of antibiotic-medicated (AM), silver-medicated (SM) and non-medicated (NM) ventricular catheters in controlling infection rate. We aim to quantitatively synthesize the current evidence after addition of the three-armed British Antibiotic and Silver Impregnated Catheters for ventriculoperitoneal Shunts (BASICS) trial, understand the need for further evidence using trial sequential analysis (TSA) and incorporate the indirect evidence using network meta-analysis (NMA). Randomized controlled trials (RCTs) comparing AM, SM and NM ventriculoperitoneal shunt (VPS) or external ventricular drain (EVD) were included. Antibiotic-medicated VPS show a significantly lower infection rate as compared to non-medicated VPS (RR 0.44; 95% CI: 0.27-0.73; p = 0.001), however, TSA reveals need for further evidence. SM including both EVD as well as VPS were found to be inferior to AM while no significant difference was found in comparison to the NM catheters. In NMA for VPS, the AM were found to be significantly better than SM (RR 0.41, 95% CI: 0.22-0.75) as well as NM (RR 0.42; 95% CI: 0.25-0.71) with a SUCRA of 99.8% and a mean rank of 1. However, antibiotic medicated shunts did not show a statistically significant association with reoperation rate (RR 0.99; 95% CI:0.81-1.20; p = 0.9) with no further need for evidence as per TSA.

Nursing assistance in patient care with external ventricular drain: a scoping review

OBJECTIVES

to map the available evidence about nursing care aimed at adult patients using external ventricular drain.

METHODS

this is a review using the scoping review method.

RESULTS

Initially, 965 studies were identified and, after the eligibility criteria, a sample of 54 publications was obtained. Each of them was assessed according to GRADE, resulting in three studies with high quality; 14 with moderate quality; 32 with low quality; and five with very low quality. It was highlighted 20 nursing care subdivided into nine categories, namely: drainage system; bed positioning and mobilization; catheter care; monitoring of intracranial pressure; and medication administration.

CONCLUSIONS

the scoping review made it possible to identify the main nursing care directed to adult patients undergoing placement of external ventricular drain from the evidence available to date.

Predictors of ventriculostomy infection in a large single-center cohort

OBJECTIVE

External ventricular drain (EVD) placement is a common neurosurgical procedure. While this procedure is simple and effective, infection is a major limiting factor. Factors predictive of infection reported in the literature are not conclusive. The aim of this retrospective, single-center large series was to assess the rate and independent predictors of ventriculostomy-associated infection (VAI).

METHODS

The authors performed a retrospective chart review of consecutive patients who underwent EVD placement between January 2012 and January 2018.

RESULTS

A total of 389 patients were included in the study. The infection rate was 3.1% (n = 12). Variables that were significantly associated with VAI were EVD replacement (OR 10, p = 0.001), bilateral EVDs (OR 9.2, p = 0.009), duration of EVD placement (OR 1.1, p = 0.011), increased CSF output/day (OR 1.0, p = 0.001), CSF leak (OR 12.9, p = 0.001), and increased length of hospital stay (OR 1.1, p = 0.002). Using multivariate logistic regression, independent predictors of VAI were female sex (OR 7.1, 95% CI 1.1–47.4; p = 0.043), EVD replacement (OR 8.5, 95% CI 1.44–50.72; p = 0.027), increased CSF output/day (OR 1.01, 95% CI 1.0–1.02; p = 0.023), and CSF leak (OR 15.1, 95% CI 2.6–87.1; p = 0.003).

CONCLUSIONS

The rate of VAI was 3.1%. Routine CSF collection (every other day or every 3 days) and CSF collection when needed were not associated with VAI. The authors recommend CSF collection when clinically needed rather than routinely.

Securing CSF catheters to the skin: from sutures and bolt system to subcutaneous anchoring device towards zero complications

INTRODUCTION

Securing the catheter to the skin either with sutures or staples and to the skull with bolt system still represents the most common options in the management of CSF external drainage. However, these options bear an unavoidable risk of complications. This problem is common to vascular accesses and has been successfully overcome with the introduction of device for subcutaneous anchoring (SecurAcath®, Interrad Medical, Inc., Plymouth, Minnesota), which has rapidly become the standard of care in this field.

METHODS

We report our experience with the use of SecurAcath® to secure CSF drainage, either ventricular or spinal. Results were compared with literature data.

RESULTS

Since 2015, SecurAcath® was used in 209 patients (mean age 7 years) to secure 195 external cranial catheters (either ventricular or subdural or intralesional) and 16 spinal drainages. Indwell time ranged from 5 to 30 days. No complication related to the use of the device was observed. In particular, there was no case of dislocation or accidental pullout of the catheter. Rate of infection, or superinfection in case of ventricular catheter implanted for CSF infection, was null.

CONCLUSIONS

SecurAcath® is a safe and effective device to secure CSF external catheters, with several relevant advantages, including easy placement and maintenance. Moreover, it may stay in place for the whole duration of the catheter without any skin tissue trauma and allows a complete antisepsis of the exit site, thus reducing local skin complications. This factor has significant impact on the reduction of infection rate of external CSF catheters.

Influence of Ward Environments on External Ventricular Drain Infections: A Retrospective Risk Factor Analysis

Background: Ventriculostomy-related infection (VRI) is one of the most severe and common complications of external ventricular drains (EVD). Ward environment is closely related to hospital-acquired infection, but its role in EVD infection is unclear. For some other recognized risk factors, clinical evidence also remains complicated and undetermined. We aimed to evaluate ward environment including multi-bed accommodation and intensive care unit (ICU) stay as potential risk factors for VRI, as well as to confirm those already known factors. Methods: We reviewed EVDs retrospectively in our center between January 2012 and January 2017. Univariable and logistic regression analysis were performed to identify risk factors for EVD-related infection. Results: A total of 284 patients who underwent EVD procedure were included. Thirty-six (12.7%) developed EVD-related infection. Univariable analysis revealed that the infection group had longer intensive care unit (ICU) stay (6.81 vs. 3.65 days, p = 0.045) but multi-bed accommodation showed no statistical difference between the two groups (p = 0.404). Univariable analysis also showed VRI patients had lower pre-operational Glasgow Coma Scale (6.89 vs. 9.32, p = 0.001), longer drainage placement duration (11.4 vs. 8.30 days, p < 0.001), greater numbers of cerebrospinal fluid (CSF) sampling (3.89 vs. 1.73, p < 0.001), higher percentage of pre-operational artificial airway status (50.0% vs. 18.1%, p < 0.001), and higher percentage of intracranial hemorrhage diagnosis (88.9% vs. 73.8%, p = 0.048). Logistic regression analysis demonstrated longer post-operational ICU stay (>5 days, odds ratio [OR] = 3.21, p = 0.026) as independent risk factor for EVD-related infection. Other independent risk factors included CSF sampling counts (>3, OR = 5.14, p <0.001), EVD duration (>7 days, OR = 3.85, p = 0.028), and pre-operational artificial airway status (OR = 2.85, p = 0.038). Conclusions: Longer post-operational ICU stay, frequent CSF sampling, longer duration of EVD placement, and pre-operational intubation are independent risk factors for EVD infection. Multi-bed accommodation and bilateral EVD placement have no substantial influence on VRI risk.

Healthcare-Associated Infections in the Neurocritical Care Unit

PURPOSE OF REVIEW

This article summarizes updated data and knowledge on healthcare-associated infections in the neurocritical care unit, with a focus on central nervous system infections and systemic infectious complications in patients with acute brain disease. It also reviews the concept of brain injury-induced immune modulation, an underlying mechanism to explain why the neuro-ICU population is particularly susceptible to infections.

RECENT FINDINGS

Healthcare-associated infections in the neuro-ICU are common: up to 40 % of meningitides in the developed world are now healthcare-associated. The number of gram-negative infections is rising. New diagnostic approaches attempt to aid in the diagnosis of healthcare-associated meningitis and ventriculitis. Healthcare-associated infections in the neurocritical care unit remain a challenge for diagnosis, treatment, and prevention. Gaining a better understanding of at-risk patients and development of preventative strategies will be the goal for future investigation.

Synthesis and Application of Silver Nanoparticles (Ag NPs) for the Prevention of Infection in Healthcare Workers

Silver is easily available and is known to have microbicidal effect; moreover, it does not impose any adverse effects on the human body. The microbicidal effect is mainly due to silver ions, which have a wide antibacterial spectrum. Furthermore, the development of multidrug-resistant bacteria, as in the case of antibiotics, is less likely. Silver ions bind to halide ions, such as chloride, and precipitate; therefore, when used directly, their microbicidal activity is shortened. To overcome this issue, silver nanoparticles (Ag NPs) have been recently synthesized and frequently used as microbicidal agents that release silver ions from particle surface. Depending on the specific surface area of the nanoparticles, silver ions are released with high efficiency. In addition to their bactericidal activity, small Ag NPs (<10 nm in diameter) affect viruses although the microbicidal effect of silver mass is weak. Because of their characteristics, Ag NPs are useful countermeasures against infectious diseases, which constitute a major issue in the medical field. Thus, medical tools coated with Ag NPs are being developed. This review outlines the synthesis and utilization of Ag NPs in the medical field, focusing on environment-friendly synthesis and the suppression of infections in healthcare workers (HCWs).

The SiLuDrain Trial: a prospective randomized controlled trial comparing standard versus silver-impregnated lumbar drains

OBJECTIVE

Catheter-associated cerebrospinal fluid (CSF) infection remains a serious event, especially for patients in neurocritical care units. The use of external ventricular drain (EVD) catheters impregnated with antimicrobial substances has led to a significant reduction of infection rates. This study was undertaken to compare the use of antimicrobial, silver-impregnated external lumbar drains (si-ELDs) and conventional ELDs.

METHODS

Patients with an indication for ELD placement were randomized to receive either a conventional or an si-ELD catheter. Regular assessment for CSF infections and device-related complications was performed. Neurosurgeons placing the ELD rated the usability and handling of the catheter on a 6-item ordinal performance scale (range: 1, very bad, to 5, very good). All microorganisms isolated in this study were tested for silver-susceptibility via a catheter-roll method.

RESULTS

A total of 48 patients were enrolled in the trial. The si-ELD catheters showed a nonsignificantly lower infection rate compared to conventional ones (4.2% vs 16.7%, p = 0.16). The majority of infections were caused by Staphylococcus species. Device-related complications occurred significantly less often with silver-impregnated-catheters than with conventional ones (8.3% vs 37.5%, p = 0.02). The usability was rated significantly better for si-ELDs (p = 0.003). Antimicrobial susceptibility was shown for si-ELDs against various Staphylococcus spp., but Candida parapsilosis and Escherichia coli were not affected by this antimicrobial agent.

CONCLUSIONS

Silver-impregnated ELD catheters, which could potentially reduce the number of CSF infections, show significantly better properties in regard to handling and fewer device-related complications. Whether they are superior to antibiotic-impregnated catheters or a clinical regimen involving antibiotic prophylaxis remains to be proven.Clinical trial registration no.: DRKS00013513 (Deutsches Register Klinischer Studien).