Clinical, biological, and microbiological pattern associated with ventriculostomy-related infection: a retrospective longitudinal study

Impact of Subarachnoid Hemorrhage in Ventriculostomy-Related Infections Prospective Comparison of Two Neurosurgical Injury Contexts

BACKGROUND

Long thought to be immune privileged, the central nervous system is far from being devoid of local immunity. Subarachnoid hemorrhage (SAH) and traumatic brain injury represent 2 distinct central nervous system injury situations which, while both exposed to external ventricular drains, present different incidences of ventriculostomy-related infection (VRI). We sought to compare VRI incidence and initial cerebrospinal fluid (CSF) inflammatory profiles in these 2 clinical situations.

METHODS

From 2015 to 2020, 227 patients treated for SAH (193) or traumatic brain injury (34) with an external ventricular drain were prospectively included. CSF samples were sent daily for microbiological examination, cell count, and biochemical analysis. VRI was defined as a positive CSF culture associated with CSF profile modifications and clinical signs. Ventriculostomy-related colonization was defined as positive catheter culture at removal. Positive events were defined as VRI and/or ventriculostomy-related colonization.

RESULTS

Eleven patients suffered from VRI, with an incidence of 3.6 VRI per 1000 catheter-days. All VRIs occurred among SAH patients without a significant difference. Median duration of drainage was 12 (7-18) days, there were no significant differences for known VRI risk factors. Positive events were significantly higher in SAH patients (20.7% vs. 2.9%, P = 0.013). Inflammatory CSF markers and serum white blood cells were higher in SAH patients.

CONCLUSIONS

Local inflammatory markers were markedly higher in SAH than in traumatic brain injury. However, positive events were more frequent in SAH. Furthermore, SAH may be a risk factor for VRI. Hypothesis that a primary injury to the subarachnoid space could impair central nervous system immune functions should be explored.

Prospective Comparative Study of External Ventricular Drain Catheter Colonization: Antibiotic-Impregnated versus Conventional Drains

OBJECTIVE

Our aim was to compare the prevalence of biofilm formation on antibiotic-impregnated (AIC) versus standard (SC) external ventricular drain (EVD) catheters.

METHODS

From March 2018 to November 2020, all consecutive EVD catheters inserted in adult patients were included. After removal, EVD catheters were analyzed under scanning electronic microscopy, on both extraluminal and intraluminal faces. Standard culture of catheter tips was also performed.

RESULTS

Overall, 114 catheters were included in 101 patients. There were 48 AICs and 66 SCs. Standard culture showed that ventriculostomy-related colonization was more frequent in SC than in AIC (26 vs. 10%; P = 0.06). Gram-negative rods accounted for 25% of ventriculostomy-related colonization in AICs, and none was documented in SCs. Scanning electronic microscopy observation showed mature biofilm on more than 80% of catheters, without significant difference between catheter type. Also, there was no difference between extraluminal and intraluminal colonization rate. There were 2 ventriculostomy-related infections in each group (5% and 3% among AICs and SCs respectively; P = 1).

CONCLUSIONS

Mature biofilm presence on the intraluminal and the extraluminal faces is similar on AICs and SCs. Accordingly, AICs do not seem to efficiently prevent biofilm formation on EVD catheters. The impact of AICs on the microbiological epidemiology of colonizing biofilm should be further evaluated.

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.

Longitudinal ventricular cerebrospinal fluid profile in patients with spontaneous subarachnoid hemorrhage

Background

Spontaneous subarachnoid hemorrhage (SAH) is a severe neurological disease that frequently requires placement of external ventricular drainage (EVD). Cerebrospinal fluid (CSF) obtained via the drain is used to detect potential complications of SAH.

Objective

This study aimed to describe the longitudinal profile of routine CSF parameters in patients with SAH and to identify associations with neurological complications.

Methods

A total of thirty-three patients with spontaneous SAH who required an EVD and had at least three consecutive CSF samples collected over a period of more than 7 days were included in this study.

Results

A median of 6 longitudinally collected CSF samples per patient were available within 1–22 days after SAH onset. Overall, red blood cells (RBC) steadily decreased over time, whereas white blood cells (WBC) and total protein (TP) increased until days 6 and 13, respectively, and decreased thereafter. The estimated decay rates of RBC, WBC, and TP were 28, 22, and 6% per day. Distinct CSF patterns over time were linked to known complications after SAH. Patients with rebleeding showed increased RBC, TP, and phagocytosing cells compared to patients without re-bleeding. For ventriculitis, an elevated cell index with a higher proportion of granulocytes was characteristic. CSF of patients with delayed cerebral ischemia showed increased RBC and WBC compared to patients without DCI. Early CSF WBC and cell index were predictive for the occurrence of DCI and ventriculitis later during the disease course. The amount of daily CSF drainage via EVD had no impact on routine CSF parameters.

Conclusion

Longitudinal CSF characteristics are associated with SAH-related complications.

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.

Ventriculitis: Infection or Inflammation

Ventriculitis, or infection of the cerebrospinal fluid, in the presence of external ventricular drains (EVD), is an important complication and associated with substantial mortality, morbidity, and healthcare costs. Further, the conditions that require the insertion of an EVD, such as neurotrauma and subarachnoid hemorrhage, are themselves associated with inflammation of the cerebrospinal fluid. Phenotypically, patients with inflammation of the cerebrospinal fluid can present with very similar symptoms, signs, and laboratory findings to those with infection. This review examines various controversies relating to the definitions, diagnosis, challenges of differentiating infection from inflammation, prevention, and treatment of ventriculitis in patients with EVDs.

Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

Background

External ventricular drain (EVD)-related infections (EVDIs) are feared complications that are difficult to rapidly and correctly diagnose, which can lead to unnecessary treatment with broad-spectrum antibiotics. No readily available diagnostic parameters have been identified to reliably predict or identify EVDIs. Moreover, intraventricular hemorrhage is common and affect cerebrospinal fluid (CSF) cellularity. The relationship between leukocytes and erythrocytes is often used to identify suspected infection and triggers the use of antibiotics pending results of cultures, which may take days. Cell count based surveillance diagnostics assumes a homogeneous distribution of cells in the CSF. Given the intraventricular sedimentation of erythrocytes on computed tomography scans this assumption may be erroneous and could affect diagnostics.

Aims

To evaluate the consistency of cell counts in serially sampled CSF from EVDs, with and without patient repositioning, to assess the effect on infection diagnostics.

Methods

We performed a prospective single-center study where routine CSF sampling was followed by a second sample after 10 min, allocated around a standard patient repositioning, or not. Changes in absolute and pairwise cell counts and ratios were analyzed, including mixed regression models.

Results

Data from 51 patients and 162 paired samples were analyzed. We observed substantial changes in CSF cellularity as the result of both resampling and repositioning, with repositioning found to be an independent predictor of bidirectional cellular change. Glucose and lactate levels were affected, however clinically non-significant. No positive CSF cultures were seen during the study. Thirty percent (30%) of patients changed suspected EVDI status, as defined by the cell component of local and national guidelines, when resampling after repositioning.

Conclusions

CSF cell counts are not consistent and are affected by patient movement suggesting a heterogeneity in the intraventricular space. The relationship between leukocytes and erythrocytes was less affected than absolute changes. Importantly, cell changes are found to increase with increased cellularity, often leading to changes in suspected EVDI status. Faster and more precise diagnostics are needed, and methods such as emerging next generation sequencing techniques my provide tools to more timely and accurately guide antibiotic treatment.

Trial Registration NCT04736407, Clinicaltrials.gov, retrospectively registered 2nd February 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03715-1.

Assessment of Bacterial Colonization of Intracranial Pressure Transducers: A Prospective Study

OBJECTIVES

Cerebral infections related to the presence of an intraparenchymal intracranial pressure transducer (ICPT) are rare. We assessed the incidence of ICPT-related infections and colonization using culture, molecular biology, and electron microscopy.

METHODS

All consecutive patients in a neurosurgical intensive care unit who had an ICPT inserted between March 2017 and February 2018 were prospectively included. Presence of colonization on the ICPTs was assessed after removal using culture, scanning electron microscopy (SEM), and next-generation sequencing (NGS).

RESULTS

Fifty-three ICPTs (53 patients), indwelling for a median of 4 (range 3-7) days, were studied. Median patient follow-up was 3 months. SEM, microbial culture, and NGS were performed for 91%, 79%, and 72% of ICPTs, respectively; 28 ICPTs (53%) were assessed using all three techniques. No patient developed ICPT-related infection. Microbial cultures were positive for two of the ICPTs (5%); colonization was identified on all ICPTs using NGS and SEM. Mature biofilm was observed on 35/48 (73%) of ICPTs. A median of 10 (8-12) operational taxonomic units were identified for each ICPT, most being of environmental origin. There was no association between biofilm maturity and antimicrobial treatment or duration of ICPT insertion. Antimicrobial treatment was associated with decreased alpha and beta-diversity (p = 0.01).

CONCLUSIONS

We observed no ICPT-related cerebral infections although colonization was identified on all ICPTs using NGS and SEM. Mature biofilm was the main bacterial lifestyle on the ICPTs.

Factors and measures predicting external CSF drain-associated ventriculitis

Objective

To determine the diagnostic value of clinical factors and biochemical or microbiological measures for diagnosing a drain-associated ventriculitis, we summarized the available evidence.

Methods

We performed a systematic review and meta-analysis of studies of patients with external ventricular CSF drains who developed drain-associated ventriculitis by searching MEDLINE, EMBASE, and CENTRAL electronic database. We reported the occurrence of abnormal test results in patients with and without drain-associated ventriculitis. For continuous variables, we recalculated mean values presented in multiple studies.

Results

We identified 42 articles published between 1984 and 2018 including 3,035 patients with external CSF drains of whom 697 (23%) developed drain-associated bacterial ventriculitis. Indications for drain placement were subarachnoid, intraventricular or cerebral hemorrhage or hemorrhage not further specified (69%), traumatic brain injury (13%), and obstructive hydrocephalus secondary to a brain tumor (10%). Fever was present in 116 of 162 patients with ventriculitis (72%) compared with 80 of 275 (29%) patients without ventriculitis. The CSF cell count was increased for 74 of 80 patients (93%) with bacterial ventriculitis and 30 of 95 patients (32%) without ventriculitis. CSF culture was positive in 125 of 156 episodes classified as ventriculitis (80%), and CSF Gram stain was positive in 44 of 81 patients (54%). In patients with ventriculitis, PCR on ribosomal RNA was positive on 54 of 78 CSF samples (69%).

Conclusion

Clinical factors and biochemical and microbiological measures have limited diagnostic value in differentiating between ventriculitis and sterile inflammation in patients with external CSF drains. Prospective well-designed diagnostic accuracy studies in drain-associated ventriculitis are needed.

Durability of antimicrobial activity of antibiotic-impregnated external ventricular drains: a prospective study

Background

Antibiotic-impregnated external ventricular drains (AI-EVDs) have a debated efficacy in clinical studies.

Objectives

Our aim was to assess the durability of antimicrobial activity of AI-EVDs used in clinical settings.

Methods

From April 2017 to January 2018, all consecutive AI-EVDs (Bactiseal™) inserted in adult patients were prospectively included. After removal, each AI-EVD was cultured and assessed for antimicrobial activity on both internal and external sides of AI-EVDs. Catheters were each challenged with a single Staphylococcus strain [MSSA, MRSA or methicillin-resistant Staphylococcus epidermidis (MRSE)]. MS was used to measure residual concentrations of rifampicin and clindamycin.

Results

Sixty-five AI-EVDs were included (56 patients). Among these, 21 were challenged with MSSA, 23 with MRSA and 21 with MRSE. Five ventriculostomy-related colonizations (9%) and two ventriculostomy-related infections (4%) occurred. Staphylococcus was the main bacterium responsible for colonization (4/5). AI-EVD inhibition decreased significantly against MRSA and MRSE according to duration of catheterization (for external and internal sides, P < 0.02) and overall volume of CSF drained (P < 0.005 for both sides against MRSE, P < 0.005 for external side against MRSA), but not against MSSA. Clindamycin concentration was not correlated with duration of catheterization or CSF volume drained, but <20% of initial concentration was recovered even after 5 days of AI-EVD dwelling. Conversely, rifampicin concentration showed a rapid and significant decline correlated to duration and CSF volume (P < 0.001 and P = 0.03, respectively).

Conclusions

Antimicrobial activity of AI-EVDs dropped quickly in vivo. Antimicrobial impregnation did not prevent AI-EVD colonization by susceptible strains in 9% of the cases.

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

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

Natural history of ventriculostomy-related infection under appropriate treatment and risk factors of poor outcome: a retrospective study

OBJECTIVE

The authors aimed to describe the natural history of ventriculostomy-related infections (VRIs) under appropriate treatment and to assess risk factors for poor outcome.

METHODS

All patients older than 18 years in whom an external ventricular drain (EVD) had been implanted and who had developed a VRI requiring treatment were included in this retrospective study. D0 was defined as the first day of antibiotic administration. Clinical and biological parameters were compared each day beginning with D1 and ending with D10 to those of D0. The authors defined D0 in a control group as the day a CSF culture came back positive, without any sign of infection. The authors then searched for poor prognostic factors in the VRI group.

RESULTS

Among 567 patients requiring an EVD between January 2007 and October 2017, 39 developed a VRI. Most were monomicrobial infections, and 47 microbes were responsible (45% were gram-positive cocci). Clinical parameters differed significantly from the control group during the first 2 days and then returned to baseline. The CSF parameters differed significantly from the control group for a longer period, returning to baseline after 5 days. CSF sterilization occurred in a median time of 2 days. An intrathecal route or EVD exchange was not associated with a poor outcome. No clinical or biological parameter between D3 and D5 was linked to outcome.

CONCLUSIONS

Clinical status improved faster than CSF parameters (before and after D5, respectively). Some CSF parameters remained abnormal until D10. Body temperature and microbiological cultures normalized faster than other parameters.

Correlation between vancomycin penetration into cerebrospinal fluid and protein concentration in cerebrospinal fluid/serum albumin ratio

Bacterial meningitis is a life-threatening condition. Vancomycin (VCM) is one of the antibiotics used as empirical therapy for bacterial meningitis. It is essential to maintain an adequate concentration of VCM in cerebrospinal fluid (CSF) to treat bacterial meningitis effectively. VCM administered intravenously must pass the blood-brain barrier (BBB) to enter the CSF and the extent of VCM penetration into CSF varies widely among patients. Previous report indicated that CSF albumin level is useful for estimation of VCM CSF penetration. However, CSF albumin level is not measured in routine practice. We focused on CSF protein concentration that is generally examined at the beginning of diagnosis and treatment of bacterial meningitis. We examined the relationship between CSF protein concentration/serum albumin ratio and the extent of VCM penetration into CSF. This retrospective study involved 7 patients admitted to our hospital who were treated with VCM for suspected bacterial meningitis. The VCM concentrations in serum and CSF were 17.6 ± 7.2 μg/mL and 3.31 ± 3.14 μg/mL, respectively. The serum VCM concentrations showed no significant correlation with CSF VCM concentrations. On the other hand, the protein concentration in CSF/serum albumin ratio showed a strong positive correlation with the VCM CSF/serum ratio (r = 0.877, p < 0.005). Our study indicates that the ratio of CSF protein concentration/serum albumin is likely useful for estimating the approximate VCM CSF/serum ratio. This could contribute to an improvement in the treatment of bacterial meningitis.

Modalities and accuracy of diagnosis of external ventricular drainage-related infections: a prospective multicentre observational cohort study

BACKGROUND

Device infection is a major complication of placement external ventricular drains (EVD). Diagnostic features are often masked by underlying disease or cerebrospinal fluid (CSF) contamination by blood. We aim to assess which diagnostic modalities are applied for EVD-related infection (ERI) diagnosis and evaluate their accuracy.

METHODS

This observational prospective study included 187 adult patients with an EVD. Modalities of clinical diagnosis of ERI diagnosed by treating physicians on clinical grounds and blood and CSF analysis (clinically diagnosed ERI (CD-ERI)) were assessed prospectively. Additionally, the diagnostic accuracy of clinical and laboratory parameters for the diagnosis of culture proven ERI (CP-ERI) was evaluated, using data of the study patients and including a retrospective cohort of 39 patients with CP-ERI.

RESULTS

Thirty-one CD-ERIs were diagnosed in the prospective cohort. Most physicians used CSF analysis to establish the diagnosis. ROC analysis revealed an AUC of 0.575 (p = 0.0047) for the number of positive SIRS criteria and AUC of 0.5420 (p = 0.11) for the number of pathological neurological signs for diagnosis of CP-ERI. Diagnostic accuracy of laboratory values was AUC 0.596 (p = 0.0006) for serum white blood cell count (WBCC), AUC 0.550 (p = 0.2489) for serum C-reactive protein, AUC 0.644 (p < 0.0001) for CSF WBCC and AUC 0.690 for CSF WBC/red blood cell count ratio (both p < 0.0001). Neither a temporal trend in potential predictors of CP-ERI nor a correlation between clinical diagnosis and proven CSF infection was found.

CONCLUSIONS

Clinicians base their diagnosis of ERI mostly on CSF analysis and occurrence of fever, leading to over-diagnosis. The accuracy of the clinical diagnosis is low. Commonly used clinical and laboratory diagnostic criteria have a low sensitivity and specificity for ERI.

Recurrent sampling and ventriculostomy-associated infections: a case-control study

BACKGROUND

External ventricular drain (EVD) insertion is a common neurosurgical procedure with a significant risk of ventriculostomy-associated infections (VAIs), other morbidities and mortality. Several risk factors have been identified but their effect is unclear.

OBJECTIVE

Our primary objective was to assess whether recurrent EVD sampling increased the risk of VAIs. The secondary objective was to explore the effect of sampling frequency, duration of EVD stay, presence of cerebrospinal fluid leak and concurrent infections.

METHODS

Ours was a retrospective, single-centre, age-matched, case control study of 83 patients and 249 controls who underwent EVD insertion between 1 January 2010 - 31 December 2016. Patients with primary CNS infections, age under 1 year and death within 5 days of EVD insertion were excluded. Blinded abstractors collected all patient data through the electronic patient record system and regression analysis was used to compare the two groups.

RESULTS

Sampling the EVD more than once did not increase the risk of infection (OR 0.47, 95% CI 0.27-0.83, p = 0.01). Risk factors significantly associated with VAI included CSF leak (OR 2.06, 95% CI 1.16-3.67, p = 0.01), concurrent infection (OR 1.85, 95% CI 1.09-3.16, p = 0.02), and an EVD duration of >10 days (OR 2.28, 95% CI 1.24-4.18, p = 0.01).

CONCLUSION

Our findings do not support the notion that increased sampling of EVDs is associated with a higher risk of VAI. CSF leaks, concurrent infection and long-term EVDs are also statistically significant risk factors for infection.

Bacterial colonisation of suture material after routine neurosurgical procedures: relevance for wound infection

BACKGROUND

Wound healing impairment is a serious problem in surgical disciplines which may be associated with chronic morbidity, increased cost and patient discomfort. Here we aimed to investigate the relevance of bacterial colonisation on suture material using polymerase chain reaction (PCR) to detect and taxonomically classify bacterial DNA in patients with and without wound healing problems after routine neurosurgical procedures.

METHODS

Repeat surgery was performed in 25 patients with wound healing impairment and in 38 patients with well-healed wounds. To determine the presence of bacteria, a 16S rDNA-based PCR detection method was applied. Fragments of 500 bp were amplified using universal primers which target hypervariable regions within the bacterial 16S rRNA gene. Amplicons were separated from each other by single-strand conformation polymorphism (SSCP) analysis, and finally classified using Sanger sequencing.

RESULTS

PCR/SSCP detected DNA of various bacteria species on suture material in 10/38 patients with well-healed wounds and in 12/25 patients with wound healing impairment including Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes and Escherichia coli. Microbiological cultures showed bacterial growth in almost all patients with wound healing impairment and positive results in PCR/SSCP (10/12), while this was the case in only one patient with a well-healed wound (1/10).

CONCLUSIONS

Colonisation of suture material with bacteria occurs in a relevant portion of patients with and without wound healing impairment after routine neurosurgical procedures. Suture material may provide a nidus for bacteria and subsequent biofilm formation. Most likely, however, such colonisation of sutures is not a general primer for subsequent wound infection.

Polymerase chain reaction based detection of bacterial 16S rRNA gene in the cerebrospinal fluid in the diagnosis of bacterial central nervous system infection in the course of external cerebrospinal fluid drainage. Comparison with standard diagnostics currently used in clinical practice

BACKGROUND AND PURPOSE

External drainage of cerebrospinal fluid (CSF) is a commonly used neurosurgical procedure. Complications of the procedure comprise central nervous system (CNS) bacterial infections, the frequency of which is estimated at around 6-10%. Detection of these infections is ineffective in many cases. The aim of the study was to evaluate the usefulness of a polymerase chain reaction (PCR)-based detection of bacterial 16S rRNA gene (16S rDNA) in the CSF.

MATERIAL AND METHODS

The study group consisted of 50 patients. Clinical signs of CNS infection were monitored and routine laboratory and microbiological tests were performed. The results of standard methods were compared with the bacterial 16S rDNA detection.

RESULTS

Using cultures, CNS infection was diagnosed in 8 patients, colonization of the drainage catheter in 6 patients, and sample contamination in 7 patients. In the group of the remaining 29 patients, no positive CSF culture was obtained and 13 of these patients also had all negative results for 16S rDNA detection. For the remaining 16 patients of this group, CNS infection, colonization of the catheter and sample contamination were diagnosed via PCR alone. Routine biochemical CSF tests and blood inflammatory parameters had a supporting value.

CONCLUSIONS

Routine hospital tests do not provide rapid and efficient detection of the external drainage related bacterial CNS infection. It is justified to use several diagnostic methods simultaneously. The16S rDNA determination in CSF can increase the probability of detection of possible pathogens.

Is First-Line Vancomycin Still the Best Option to Treat Staphylococcus Health Care-Associated Meningitis?

BACKGROUND

Cerebrospinal fluid (CSF) penetration of vancomycin through the blood-brain barrier is poor but important inflammation improved it. Hence, vancomycin is recommended for the treatment of community meningitis. However, what about mild inflammatory health care-associated meningitis? The aim of this study was to evaluate the impact of vancomycin diffusion on CSF in Staphylococcus epidermidis health care-associated meningitis.

CASE DESCRIPTION

This was a retrospective study of all consecutive patients with S. epidermidis CSF shunt-associated infection, which was treated by continuous intravenous vancomycin after standard of care (60 mg/kg/d after a loading dose of 15 mg/kg). Patient outcome, CSF protein level, and vancomycin concentration in CSF and serum were assessed. We report 6 consecutives cases. Clinical and biologic manifestations were of mild intensity. Meningeal permeability was moderately altered with low CSF protein levels. Despite appropriate vancomycin dosage resulting in high serum concentrations, CSF remained below the S. epidermidis minimal inhibitory concentration.

CONCLUSIONS

We propose to reassess vancomycin use as first-line therapy when meningeal inflammation is mild-to-moderate in favor of antibiotics, which have a better CSF penetration.

Current practice of external ventricular drainage: a survey among neurosurgical departments in Germany

BACKGROUND

There are various recommendations, but no generally accepted guidelines, to reduce the risk of external ventricular drainage (EVD)-associated infections. The primary objective of the present study was to evaluate the current practice of EVD in a European country and to set the results in perspective to published data.

METHOD

A standardised questionnaire prepared by the Commission of Technical Standards and Norms of the German Society of Neurosurgery was sent to 127 neurosurgical units in Germany.

RESULTS

Data were analysed from 99 out of 127 neurosurgical units which had been contacted. Overall, more than 10,000 EVD procedures appear to be performed in Germany annually. There is disagreement about the location where the EVD is inserted, and most EVDs are still inserted in the operation theatre. Most units apply subcutaneous tunnelling. Impregnated EVD catheters are used regularly in only about 20 % of units. Single-shot antibiotic prophylaxis is given in more than half of the units, while continued antibiotic prophylaxis is installed in only 15/99 units at a regular basis. There are discrepancies in the management of prolonged EVD use with regard to replacement policies. Regular cerebrospinal fluid (CSF) sampling is still performed widely. There were no statistical differences in policies with regard to academic versus non-academic units.

CONCLUSIONS

This survey clearly shows that some newer recommendations drawn from published studies penetrate much slower into clinical routine, such as the use of impregnated catheters, for example. It remains unclear how different policies actually impact quality and outcome in daily routine.

From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study

Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5–56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4–41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.