Diagnostic Approach to Health Care- and Device-Associated Central Nervous System Infections.

Health care- and device-associated central nervous system (CNS) infections have a distinct epidemiology, pathophysiology, and microbiology that require a unique diagnostic approach. Most clinical signs, symptoms, and tests used to diagnose community-acquired CNS infections are insensitive and nonspecific in neurosurgical patients due to postsurgical changes, invasive devices, prior antimicrobial exposure, and underlying CNS disease. The lack of a standardized definition of infection or diagnostic pathway has added to this challenge. In this review, we summarize the epidemiology, microbiology, and clinical presentation of these infections, discuss the issues with existing microbiologic tests, and give an overview of the current diagnostic approach.

Evaluation of intraoperative glove change in prevention of postoperative cerebrospinal fluid shunt infections, and the predictors of shunt infection.

BACKGROUND: We have previously suggested that surgical gloves could be a possible means for transferring microorganisms from skin flora to shunt material during surgery. The objectives of this study were to examine (1) whether the rate of shunt infections was reduced after introducing intraoperative glove change before handling the shunt material; (2) clinical presentation of shunt infections, microbiological data, and treatment management; and (3) predictors of shunt infections. METHODS: A retrospective study of 432 shunt operations in 295 adults was undertaken over a 7-year period. Study population consisted of two groups: Group A without intraoperative glove change (2003-2006), and Group B with change of the outer pair of the initial double gloves before handling the shunt material (2006-2009). The results were compared at 6- and 12-month postoperatively. A binary logistic regression was performed to determine predictors of shunt infections. RESULTS: Overall, 46 (10.6%) infection episodes occurred in 40 (13.6%) patients. Main symptoms were fever, abdominal pain and altered mental status. Propionibacterium acnes was the frequently isolated microorganism, followed by Staphylococcus species. The infection rate was reduced only moderately from 11.8% in Group A to 9.8% in Group B (p = .472). Patients with subarachnoid haemorrhage were more likely to experience shunt infections (17.9%), compared to patients with normal pressure hydrocephalus (5.9%). An increased likelihood of shunt infections for the increased number of subsequent shunt revisions (p = .030) and a trend towards prior history of shunt infections (p = .118) was seen. After adjusting for various covariates, a decreased likelihood of shunt infections for intraoperative glove change was seen at 6-month follow-up for first-time shunt insertion (p = .050). CONCLUSION: Intraoperative glove change does not significantly reduce the risk of shunt infection. However, it seems to reduce the infection rate within 6 months in patients undergoing first-time shunt insertion only.

Cerebrospinal Fluid Shunt Reinfection and Malfunction in Ecuadorian Children with Different Reshunting Criteria After Infection. "Is It Just One Shunt After Another?"

OBJECTIVE: There is no firm evidence regarding cerebrospinal fluid (CSF) shunt reimplantation after infection in the pediatric population. The purpose of this study was to compare different criteria and analyze new shunt failure. METHODS: A cross-sectional retrospective multicenter study was performed over 6 years to study patients and each infected shunt at diagnosis, reimplantation, and after reimplantation. The patients were divided into 2 groups: group 1 (G1), reimplantation after negative serial CSF cultures during antibiotic treatment; group 2 (G2), reimplantation after negative serial pancultures after completion of antibiotics. The differences were measured with Mann-Whitney and Χ2 tests; multivariate analysis and associations were calculated using odds ratios (ORs) based on logistic regression. RESULTS: There were 137 shunt infection events in 110 patients: 28 events in G1 and 109 in G2. Significant differences were observed in the diagnosis and reimplantation. Reimplantation dysfunction in G1 was 16 (55.17%) versus 30 (27.78%) in G2 (P = 0.006). The risk of shunt malfunction after reimplantation increased for G1 reimplantation criteria (P = 0.018; OR, 3.34; confidence interval [CI], 1.23-9.05): pleocytosis at diagnosis >17 cells (P = 0.036; OR, 2.41; CI, 1.06-5.47), CSF proteins at diagnosis >182 mg/dL (P = 0.049; OR, 2.21; CI, 1.00-4.89). CONCLUSIONS: G2 reimplantation criteria were related to improved pleocytosis, CSF proteins, and blood neutrophils compared with G1. Mechanical and infectious dysfunction of the new shunt was 3 times more prevalent in G1 than in G2, considering the differences between the groups at diagnosis. Increased parameters of infection at diagnosis were associated with future malfunction more than parameters before reimplantation in both groups.

Infection rates of external ventricular drains are reduced by the use of silver-impregnated catheters.

BACKGROUND: External ventricular drainage (EVD) placement for temporary cerebrospinal fluid (CSF) diversion is a frequent therapeutic procedure. Several types of EVD catheters are currently available, some of which have an antibacterial effect. This study compares the rates of CSF infections in patients with different types of EVD catheters. METHODS: This is a retrospective study of 403 patients with a total of 529 implanted EVDs. We analyze the occurrence of EVD-associated infections, microbiological diagnosis, type of EVD catheter (plain polyurethane vs. silver-impregnated), duration of CSF diversion, primary disease, and outcome. RESULTS: There were a total of 29 patients with EVD infections in the whole study group (7.1 %). A pathogen was detected in all cases. Coagulase-negative staphylococci were detected most frequently (20 out of 29 cases, 70 %). The rate of infections by catheter type was 7.6 % (11 of 145) and 13.8 % (4 out of 29) for two different types of non-coated polyurethane catheters. Silver-impregnated polyurethane catheters became infected in 6.1 % (14 out of 228). The differences between non-coated and silver-coated catheters were statistically significant. CONCLUSIONS: This study provides comparative data on EVD infections with regard to the type of catheter. Silver-impregnated catheters showed significantly lower infection rates when compared to non-impregnated catheters. The results are critically discussed and compared with the published literature.

One year failure rate for de-novo ventriculo-peritoneal shunts in children from a small volume paediatric neurosurgical unit.

It is the belief of some that results of shunt surgery for the treatment of hydrocephalus in children are improved if the surgery is performed in high-volume centres. Currently in the UK paediatric neurosurgery is undergoing a service review. As part of this review a set of standards of care are being drafted which state that 1-year failure rates and infection rates for de-novo ventriculo-peritoneal shunts in children should be less than 40% and 10%, respectively. Our de-novo shunt infection rate (4.3%) and our 1-year failure rate (28.6%) are well within the standards set by this process and comparable to published literature from much higher volume centres.

Impact of antibiotic-impregnated catheters on the timing of cerebrospinal fluid infections in non-traumatic subarachnoid hemorrhage.

BACKGROUND: Subarachnoid hemorrhage (SAH) has been recognized as a risk factor for ventriculostomy-related infections (VRI). In addition to the hemorrhagic cerebrospinal fluid (CSF), the potential need for prolonged catheterization may contribute to the increased CSF infection rate in this population. The use of antibiotic-impregnated catheters (AIC) has effectively reduced the risk of VRI. Herein, we examined specifically the impact of systematic insertion of AIC on the timing of CSF infections in SAH patients. METHODS: Retrospective review of patients admitted between April 2006 to March 2009 with a non-traumatic SAH who required an external ventriculostomy. Only patients with AIC were included. A meningitis or ventriculitis was diagnosed according to the published criteria of the Center for Disease Control and Prevention. RESULTS: This study includes 75 patients in which 97 drains were inserted. Seven infections (7/75 = 9.3%) occurred over 1,024 drainage days (DD), resulting in a rate of 6.8 infections/1,000 DD. The mean drainage time was 15.4 days in the infected AIC group compared with 10.2 days in the non-infected AIC group. No infection occurred before day 9 of drainage and 71% (5/7) occurred after more than 2 weeks of drainage. The observed timing of infections is delayed in comparison with that reported in series using non-AIC, which typically occur prior to the 10th day of drainage. CONCLUSIONS: In the high-risk population of non-traumatic SAH, the use of AIC delays the occurrence of infection compared with that reported with non-antibiotic-impregnated catheters. This may orient management strategies in SAH patients requiring a ventriculostomy.

Value of Cerebrospinal Fluid Lactate Levels in Diagnosing Shunt Infections in Pediatric Patients.

OBJECTIVE: The diagnosis and timely treatment of shunt infections (SI) in children is of paramount importance. In some cases, the standard cerebrospinal fluid (CSF) variables will not be sufficient for an accurate diagnosis of SI. CSF lactate (LCSF) has been found to assist in differentiating bacterial from nonbacterial meningitis in non-neurosurgical patients. To the best of our knowledge, the use of lactate in diagnosing or confirming the presence of SI has not yet been discussed. The goal of the present study was to describe the role of LCSF levels in children with shunts and Ommaya reservoirs and to evaluate its role in the accurate diagnosis of shunt-related infection. METHODS: We retrospectively collected data for a consecutive series of pediatric patients treated at a large tertiary pediatric neurosurgical department, for whom CSF samples from shunts had been collected during a 2-year period (2016-2017). The lactate levels were correlated with the presence of SI. RESULTS: A total of 61 CSF samples were analyzed, with 6 SIs found. The LCSF levels and white blood cell count were both found to correlate with the presence of CSF infections. A cutoff value of ≥2.95 mmol/L reached a sensitivity of 83%, specificity of 83%, and positive predictive value of 50%. LCSF <2.95 mmol/L had a negative predictive value of 96%. CONCLUSIONS: LCSF levels can be used as an additional chemical marker for the diagnosis and confirmation of SIs. An LCSF value of <2.95 mmol/L had a high negative predictive value.

Ventriculitis associated with extraventricular drainage: etiology, diagnosis and treatment focused on neurocritic care units.

Ventriculitis after extraventricular drainage is a very important neurosurgical complication in neurocritical care units. It is necessary to make an early diagnosis, given that the morbidity and mortality secondary to it can be variable, and complicate the evolution of neurocritical patients. Despite this, ventriculostomy continues to be an important pillar in monitoring and treatment. Given the urgency of ventriculitis associated with multiresistant germs, new antimicrobial drugs have emerged as part of the treatment, as intraventricular routes have been proposed within the new investigations. However, the foregoing does not yet have sufficient bases to be able to support it. The present review was carried out with the aim of contributing to an early diagnosis and treatment of ventriculitis associated with extra ventricular drainage in neurocritical patients, and in this way to contribute to improve survival and prevent fatal outcomes in these patients.

La ventriculitis posterior a un drenaje extraventicular constituye una complicación neuroquirúrgica muy importante en las unidades de cuidados neurocríticos. Se hace necesario realizar un diagnóstico precoz, dado que la morbimortalidad secundaria a esta puede ser variable y complicar la evolución de los pacientes neurocríticos. A pesar de esto, la ventriculostomía continúa siendo un pilar importante en el monitoreo y el tratamiento. Ante la urgencia de ventriculitis asociadas a gérmenes multirresistentes han surgido nuevos fármacos antimicrobianos como parte del tratamiento, al igual que se han propuesto vías intraventriculares dentro de las nuevas investigaciones. Sin embargo, lo anterior aún no tiene bases suficientes para poder ­sustentarlo. La presente revisión se realizó con el objetivo de contribuir a un diagnóstico precoz y al tratamiento de la ventriculitis asociada a drenaje extraventricular en pacientes neurocríticos, y de esta forma poder mejorar la sobrevida y prevenir desenlaces fatales en estos pacientes.

Results of a quality improvement initiative reassessing an institutional lumbar drain infection prevention protocol.

OBJECTIVE The objective of this study was to determine the effects of a quality improvement initiative in which daily antibiotics and daily sampling of cerebrospinal fluid (CSF) were discontinued for patients with lumbar drains. METHODS The frequency of surgical site infections (SSIs), antibiotic-related complications (development of Clostridium difficile infection [CDI] and growth of resistant bacteria), and cost for patients with lumbar drains were compared during 3 periods: 1) prolonged prophylactic systemic antibiotics (PPSA) until the time of drain removal and daily CSF sampling (September 2013-2014), 2) PPSA and CSF sampling once after placement then as needed (January 2015-2016), and 3) antibiotics only during placement of the lumbar drain and CSF sampling once after placement then as needed (April 2016-2017). RESULTS Thirty-nine patients were identified in period 1, 53 patients in period 2, and 39 patients in period 3. There was no change in the frequency of SSI after discontinuation of routine CSF testing or PPSA (0% in period 1, 2% in period 2, and 0% in period 3). In periods 1 and 2, 3 patients developed infections due to resistant organisms and 2 patients had CDI. In period 3, 1 patient had an infection due to a resistant organism. The median cost of CSF tests per patient was $100.68 (interquartile range [IQR] $100.68-$134.24) for patients in period 1 and $33.56 (IQR $33.56-$33.56) in periods 2 and 3 (p < 0.001). The median cost of antibiotics per patient was $26.32 (IQR $26.32-$30.65) in periods 1 and 2 and $3.29 ($3.29-$3.29) in period 3 (p < 0.001). The cost associated with growth of resistant bacteria and CDI was $91,291 in periods 1 and 2 and $25,573 in period 3. CONCLUSIONS After discontinuing daily antibiotics and daily CSF sampling for patients with lumbar drains, the frequency of SSI was unchanged and the frequency of antibiotic-related complications decreased.

Shunt Nephritis: An Increasingly Unfamiliar Diagnosis.

BACKGROUND: Shunt nephritis is a rare, reversible immune-complex mediated complication of cerebrospinal fluid (CSF) shunt infection that can progress to end-stage renal disease and even death if diagnosis is delayed. CASE DESCRIPTION: The present case report details the manifestation and clinical course of shunt nephritis in a 50-year-old patient who presented with symptoms of nephrotic syndrome 30 years after ventriculojugular shunt placement. Diagnosis was delayed due to initial negative CSF and blood cultures, but a later CSF culture was positive for Propionibacterium acnes. After treatment with intravenous antibiotics and complete removal of shunt with subsequent replacement with a new ventriculoperitoneal shunt, the nephritic symptoms resolved, but the patient continued to have reduced kidney function consistent with stage IIIa chronic kidney disease. CONCLUSION: This case emphasizes the clinical importance of having a high index of suspicion in patients with a ventricular shunt who present with symptoms consistent with nephritis, even in the setting of negative cultures and delayed presentation.

Do antibiotic-impregnated shunts in hydrocephalus therapy reduce the risk of infection? An observational study in 258 patients.

BACKGROUND: Shunt infection in hydrocephalus patients is a severe, even life-threatening complication. Antibiotic-impregnated shunts (AIS) have been developed in an attempt to reduce rate of shunt infection. The study was performed to analyze if AIS can diminish the rate of shunt infection. The pathogenic nature of shunt infection in patients with AIS systems and those without antibiotic impregnated shunts (non-AIS) was compared. METHODS: Over a period of 24 months in the Department of Neurosurgery at University Hospital of Tübingen shunt surgery was performed in 258 patients. In 86 patients AIS systems were implanted. Shunt catheters were commercially impregnated with clindamycin and rifampicin. Analysis of the clinical data included sex, age, classification of hydrocephalus, shunt types and risk factors for shunt infection [age (< 1 year and > 80 years), prematurely born patients, external ventricular drainage, former shunt infection, former systemic infection, disturbance of consciousness, former radiation-/chemotherapy]. Infection rates and underlying bacterial pathogens of patients with AIS were compared to patients with implanted non-AIS systems (172 patients). RESULTS: AIS and non-AIS patients did not differ in sex, etiology of hydrocephalus and the shunt type. In the AIS group 72 out of 86 patients had at least one risk factor (83.7 %), compared to 126 patients in the non-AIS group (73.3 %). There was no significant difference between the two groups (p = 0.0629; Fisher's exact test). In patients with no risk factors, only one patient with non-AIS suffered from shunt infection. In patients with one or more risk factors the rate for shunt infection was 7.14 % in patients with non-AIS and 6.94 % in patients with AIS. Former shunt infection (p = 0.0124) was related to higher risk for shunt infection. The use of AIS had therefore no significant advantage (p = 0.8611; multiple logistic regression). Significantly related to a shunt infection was the number of shunt surgeries. 190 interventions in the AIS group (2.21 interventions per patient) and 408 in the non-AIS group (2.37 interventions per patient) had been performed (p = 0.3063; Wilcoxon). There was no shunt infection in the group of patients on whom only one shunt surgery was performed. In patients with at least two shunt surgeries the infection rate was 9%. The infection rate in AIS patients was 5/52 (9.6 %) and in the non-AIS 10/114 (8.77 %), (p = 1.0; Fisher's exact test). Staphylococcus epidermidis was the most frequent pathogen for shunt infection. Fourteen out of 15 infections occurred within the first 6 months of surgery. The most frequent pathogen for shunt infection was S. epidermidis. No toxic or allergic complications were seen using the AIS shunt systems. The presented data show a remarkably low infection rate of 5.8 % in the non-AIS group compared to other studies which demonstrated a significant decrease in the infection rate by AIS. CONCLUSION: AIS did not significantly reduce shunt infection in hydrocephalus patients in the presented study. In the AIS group three patients suffered from shunt infections caused by skin ulceration or neurosurgical procedures with exposure of the cerebrospinal liquor after shunt implantation. AIS was not developed to prevent infection in such cases, therefore an advantage of AIS can not be excluded. In view of the presented data and the small number of reported studies a prospective randomized multicenter study is required.

Case report of a 6-year-old girl with Mycoplasma hominis ventriculoperitoneal shunt infection.

Mycoplasma hominis is a rare causative pathogen for surgical site infections after neurosurgical procedures. This organism lacks a cell wall, rendering it undetectable by Gram staining and making it resistant to beta-lactam antibiotics. In addition, some special techniques are required to identify this organism. Thus, it is very difficult to diagnose infections caused by this pathogen. Here, the authors report a pediatric case of M. hominis ventriculoperitoneal shunt (VPS) infection with central nervous system involvement for which beta-lactam antibiotics were not effective and Gram staining revealed no pathogens. Because few cases have been described that involve the treatment of M. hominis infection after neurosurgery, in this case the patient's serum and CSF were monitored for antibiotic drug concentrations. Successful treatment of the infection was achieved after approximately 6 weeks of administration of clindamycin and ciprofloxacin antibiotics in addition to external ventricular drain revision and subsequent VPS replacement. When beta-lactam antibiotics are ineffective and when Gram staining cannot detect the responsible pathogens, it is important to consider M. hominis as the atypical pathogen.

Cerebrospinal fluid shunt infections in children.

We reviewed cerebrospinal fluid (CSF) shunt infections treated in the Royal Children's Hospital, Melbourne from 1981 to 1991. Forty-one episodes of CSF shunt infection were found after 900 shunt operations, an infection rate of 4.5%. Clinical symptoms were nonspecific in 31.7% of episodes, and in 17.1% of episodes the initial CSF sample was normal on microscopy and biochemistry, although a pathogen was isolated on culture. Most episodes occurred within 4 months of the last operation on the shunt, the exception being infections caused by Haemophilus influenzae. Four patients died during treatment, but none could be attributed to infection alone. Treatment of suspected CSF shunt infection should not be withheld because of lack of firm clinical diagnosis or normal CSF microscopy, and episodes occurring more than 4 months after the last operation on the CSF shunt should receive antibiotic cover for H. influenzae.

Continuous intrathecal pump infusion of baclofen with antibiotic drugs for treatment of pump-associated meningitis. Case report.

Intrathecal baclofen administered by means of an implantable pump is being increasingly used for successful treatment of spasticity. Meningitis following intrathecally administered baclofen is a rare but serious complication that is difficult to treat without removal of the pump. Because success rates with intravenously administered antibiotic drugs for the treatment of meningitis have been low, intrathecal administration of antibiotic agents is often required to eradicate the pathogen. The authors report the case of a patient in whom Staphylococcus epidermidis meningitis developed after insertion of an intrathecal baclofen pump. The patient was successfully treated by intrathecal coadministration of vancomycin and baclofen.

Infections of cerebrospinal fluid diversion devices in adults: the role of intraventricular antimicrobial therapy.

OBJECTIVES: The precise role for intraventricular (IVT) antimicrobials in combination with systemic antibiotics in management of cerebrospinal fluid (CSF) diversion device-associated infections is uncertain. We evaluated our current practice, comparing dual therapy against systemic antimicrobials alone. METHODS: All adult patients with at least two consecutive CSF isolates who were treated for CSF diversion device-related infection over a 5-year period (2005-2010) were identified retrospectively. Clinical and laboratory parameters, microbiology, surgical and antimicrobial management, and treatment outcomes were analysed. RESULTS: Forty-eight patients were identified - 25 received IVT and systemic antibiotics (group A), and 23 systemic antibiotics alone (group B). Clinical features were similar between groups, as were causative organisms. CSF leucocyte counts differed slightly (A > B, p = 0.067) but no laboratory parameters differed significantly. Infected devices were generally revised (A = 92%, B = 91%). Mean times to CSF sterilisation and normalisation of CSF microscopy were significantly shorter for group A (p < 0.05 and p < 0.005 respectively), as was duration of hospital stay (p < 0.002) and required length of systemic antimicrobial therapy (p < 0.001). CONCLUSIONS: Our findings indicate that IVT antibiotics enhance clinical and microbiological recovery and should therefore be considered for patients with CSF infection associated with a CSF diversion device. We recommend further evaluation of this approach in a prospective, randomised, controlled trial.

[Cryptococcal meningitis in a patient with a ventriculoperitoneal shunt and monitoring for pulmonary sarcoidosis]. / Cryptococcose neuroméningée chez un patient porteur d'une valve de dérivation ventriculo-péritonéale suivi pour sarcoïdose pulmonaire.

The fungus Cryptococcus neoformans can cause common opportunistic infection in acquired immune deficiency syndrome (AIDS) patients. But other conditions can be associated with sarcoidosis. Meningoencephalitis is the most common manifestation of this disease. One of the most important neurological complications is the development of intracranial hypertension (ICH), which may result in high morbidity and mortality. We report the case of a patient harboring a ventriculoperitoneal shunt, and having contracted a cryptococcal meningitis as a risk factor for pulmonary sarcoidosis. Brain MRI showed arachnoiditis, with a mass in contact with the right frontal horn. Indian ink staining of the cerebrospinal fluid (CSF) showed positivity that was confirmed by the identification of Cryptococcus neoformans after culture. The evolution was favorable under medical treatment with removal of material. The relationship between sarcoidosis and cryptococcosis, described in the literature is not coincidental but is a rare complication of sarcoidosis of potential severity (40% of mortality). Sarcoidosis is a common systemic disease that may increase host susceptibility to CNS cryptococcal infection without any other signs or symptoms of host immunosuppression. The diagnosis of cryptococcosis should be evoked as a differential diagnosis of neuro-sarcoidosis.

Progression of cerebrospinal fluid cell count and differential over a treatment course of shunt infection.

OBJECT: The physiological reaction of CSF white blood cells (WBCs) over the course of treating a shunt infection is undefined. The authors speculated that the CSF WBC count varies with different infecting organisms in peak level and differential percentage of polymorphonuclear (PMN) leukocytes, lymphocytes, monocytes, and eosinophils. The authors hope to identify clinically useful trends in the progression of CSF WBCs by analyzing a large group of patients with successfully treated shunt infections. METHODS: The authors reviewed 105 successfully treated cases of shunt infections at Riley Hospital for Children. The study dates ranged from 2000 to 2004; this represented a period prior to the routine use of antibiotic-impregnated shunt catheters. They analyzed the following organisms: coagulase-negative staphylococci, Staphylococcus aureus, Propionibacterium acnes, Streptococcal species, and gram-negative organisms. The initial CSF sample at diagnosis was analyzed, as were levels over 14 days of treatment. Model fitting was performed to generate curves for the expected progression of the WBC counts and the differential PMN leukocytes, lymphocyte, monocyte, and eosinophil percentages. RESULTS: Gram-negative organisms resulted in a higher initial (p = 0.03) and peak WBC count with a greater differential of PMN leukocytes compared with other organisms. Propionibacterium acnes infections were associated with a significantly lower WBC count and PMN leukocytes percentage (p = 0.02) and higher eosinophil percentage (p = 0.002) than other organisms. The pattern progression of the CSF WBC count and differential percentages was consistent for all infections. There was an initial predominance of PMN leukocytes, followed by a delayed peak of lymphocytes, monocytes, and eosinophils over a 14-day course. All values trended toward zero over the treatment course. CONCLUSIONS: The initial and peak levels of CSF WBCs vary with the infecting organisms. The CSF cell counts showed a predictable pattern during the treatment of shunt infection. These trends may be useful to the physician in clinical decision making, although there is a wide range of variability.

Efficacy of silver-bearing external ventricular drainage catheters: a retrospective analysis.

OBJECT: Catheter-related infection of CSF is a potentially life-threatening complication of external ventricular drainage (EVD). When using EVD catheters, contact between the ventricular system and skin surface occurs and CSF infection is possible. The aim of this analysis was to compare the efficacy of silver-bearing EVD catheters for reducing the incidence of infection with standard nonimpregnated EVD catheters in neurosurgical patients with acute hydrocephalus. METHODS: Two hundred thirty-one consecutive patients were retrospectively reviewed. Of these, 164 were enrolled in the final analysis. Six patient charts were incomplete or missing, 15 patients were excluded because of catheter insertion within the previous 30 days, 6 because of a suspected CSF infection before ventriculostomy, 7 because the catheter was removed < 24 hours after insertion, and 33 patients because of the requirement of bilateral ventriculostomy. The control group with standard nonimpregnated EVD catheters consisted of 90 patients. The study group with silver-bearing EVDs consisted of 74 patients. For assessing the primary outcome, the authors recorded all CSF samples and liquor cell counts routinely obtained in sterile fashion. After removal of the catheters, they also reviewed microbiology reports of the removed catheters to assess colonization of the catheter tips. RESULTS: The occurrence of a positive CSF culture, colonization of the catheter tip, or liquor pleocytosis (white blood cell count > 4/microl) was approximately 2 times less in the study group with silver-bearing EVD catheters than that in the control group (18.9% compared with 33.7%, p = 0.04). Positive CSF cultures alone occurred 2 times less frequently for microorganisms in the study group (2.7% compared with 4.7%, p = 0.55). Silver-bearing catheters were 4 times less likely to become colonized as nonimpregnated EVDs (1.4% compared with 5.8%, p = 0.14). Liquor pleocytosis was half as likely in the study group (17.6% compared with 30.2%, p = 0.06). CONCLUSIONS: Although of limited sample size and thus underpowered for subgroup analysis, this analysis indicates that EVD catheters impregnated with silver nanoparticles and an insoluble silver salt may reduce the risk of catheter-related infections in neurosurgical patients.

Biofilm and the role of the ica operon and aap in Staphylococcus epidermidis isolates causing neurosurgical meningitis.

Fifty-five Staphylococcus epidermidis isolates, classified as contaminants or causing device-related meningitis, from external ventricular drain (EVD) and non-EVD cerebrospinal fluid specimens were characterized. Thirty-three of 42 (78.6%) meningitis isolates were PCR-positive for ica and aap, known determinants of polysaccharide- and protein-mediated biofilm production, whereas five of 13 (38.5%) contaminants were ica- and aap-negative; 71.4% of meningitis isolates and 84.6% of contaminants produced biofilm. ica+aap+ meningitis isolates produced more biofilm than ica+aap- isolates (p 0.0020). ica+aap- isolates did not produce more biofilm than ica-aap+ isolates (p 0.4368). Apparently, ica and aap are associated with biofilm production in S. epidermidis device-related meningitis isolates.

The impact of antibiotic-impregnated catheters on shunt infection in children and neonates.

INTRODUCTION: Infection remains a significant problem with cerebrospinal fluid (CSF) diversion procedures. Antibiotic-impregnated shunt catheters (AIS) have been introduced to prevent infection, mainly in the early post-operative period when most infections occur. We evaluate the impact on infection rates in children following the introduction of catheters impregnated with rifampicin and clindamycin. MATERIALS AND METHODS: The study was a retrospective analysis of all paediatric shunt procedures undertaken after the introduction of AIS systems in 2003. All procedures where a complete AIS system was implanted were included. For the purpose of analysis, shunt procedures were classified as de novo (group 1), clean revision (group 2) and following external ventricular drainage with either sterile CSF (group 3) or infected CSF (group 4). Results were compared to a historical cohort of shunt procedures undertaken before the introduction of AIS catheters. RESULTS: A total of 214 AIS were implanted in 150 children between October 2003 and December 2006. There were 4 infections in group 1 (8.5%), 6 infections in group 2 (5.3%) and 11 infections in groups 3 and 4 (20%). The historical control group comprised 77 shunts in 65 children. The infection rate in neonatal de novo shunts reduced from 27 to 10.4% following the introduction of AIS catheters. CONCLUSIONS: AIS catheters can reduce the number of shunt infections seen in clinical practice in certain subgroups. This has had a significant impact on the neonatal hydrocephalic population. The high risk of shunt infection after a period of external ventricular drainage raises the issue of emergence of bacterial resistance.