The incidence and risk factors of meningitis after major craniotomy in China: a retrospective cohort study

Early Identification of Correlated Risk Factors can Improve the Prognosis of Patients with Postoperative Intracranial Infection

BACKGROUND

 In this retrospective study, we explore the clinical risk factors correlated to the prognosis of patients who suffered from central nervous system infection after a neurosurgical procedure.

METHODS

 The study included 113 patients diagnosed with a postoperative intracranial infection. Several factors with clinical relevance were identified and analyzed by univariate analyses. The risk factors that showed any significant difference between the cases were analyzed by multivariate logistic regression analyses.

RESULTS

 Here we show that the duration of the drainage before infection (measured in days; Beta [B]: -0.113; odds ratio [OR]: 0.893; 95% confidence interval [CI]: 0.805-0.991; p = 0.033), the number of antibiotics used for the treatment (B: -1.470; OR: 0.230; 95% CI: 0.072-0.738; p = 0.013), and the number of leucocytes in the cerebrospinal fluid (CSF; B: -0.016; OR: 0.984; 95% CI: 0.970-0.998; p = 0.027) are risk factors for the prognosis of patients with an intracranial infection. In contrast, the duration of antibiotic treatment (measured in days; B: 0.176; OR: 1.193; 95% CI: 1.063-1.339; p = 0.003) turned out to be a positive factor for recovery from infection.

CONCLUSIONS

 Our results suggest that early identification of the correlated risk factors can improve the prognosis of patients with intracranial infection after neurosurgery.

The pharmacokinetics/pharmacodynamics of ceftazidime/avibactam for central nervous system infections caused by carbapenem-resistant Gram-negatives: a prospective study

OBJECTIVES

To describe the pharmacokinetics/pharmacodynamics (PK/PD) of ceftazidime/avibactam in critically ill patients with CNS infections.

METHODS

A prospective study of critically ill patients with CNS infections who were treated with ceftazidime/avibactam and the steady-state concentration (Css) of ceftazidime/avibactam in serum and/or CSF was conducted between August 2020 and May 2023. The relationship between PK/PD goal achievement, microbial eradication and the clinical efficacy of ceftazidime/avibactam was evaluated.

RESULTS

Seven patients were finally included. The ceftazidime/avibactam target attainment in plasma was optimal for three, quasi-optimal for one and suboptimal for three. In three patients with CSF drug concentrations measured, ceftazidime/avibactam target attainment in CSF was 100% (3/3), which was optimal. The AUCCSF/serum values were 0.59, 0.44 and 0.35 for ceftazidime and 0.57, 0.53 and 0.51 for avibactam. Of the seven patients, 100% (7/7) were treated effectively, 71.4% (5/7) achieved microbiological eradication, 85.7% (6/7) survived and 14.3% (1/7) did not survive.

CONCLUSIONS

The limited clinical data suggest that ceftazidime/avibactam is effective in the treatment of CNS infections caused by MDR Gram-negative bacilli (MDR-GNB), can achieve the ideal drug concentration of CSF, and has good blood-brain barrier penetration.

Risk and protective factors associated with wound infection after neurosurgical procedures: A meta-analysis

To systematically evaluate the risk factors for wound infection at the surgical site after neurosurgical craniotomy by meta-analysis, and to provide an evidence-based basis for preventing the occurrence of wound infection. A computerised search of PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure and Wanfang database was conducted for relevant studies on risk factors for surgical site wound infection after neurosurgical craniotomy published from the database inception to November 2023. Two researchers independently screened the literature, extracted the data and performed quality assessment in strict accordance with the inclusion and exclusion criteria. STATA 17.0 software was applied for data analysis. Overall, 18 papers with 17 608 craniotomy patients were included, of which 905 patients developed wound infections. The analysis showed that underlying diseases [OR = 2.50, 95% CI (1.68, 3.72), p < 0.001] and emergency surgery [OR = 2.47, 95% CI (1.80, 3.38), p < 0.001] were the risk factors for developing wound infections after craniotomy, age < 60 years [OR = 0.72, 95% CI (0.52, 0.98), p = 0.039] was a protective factor for wound infections; whereas sex [OR = 1.11, 95% CI (0.98, 1.27), p = 0.112] and the antimicrobial use [OR = 1.30, 95% CI (0.81 2.09), p = 0.276] were not associated with the presence or absence of wound infection after craniotomy. Underlying disease and emergency surgery are risk factors for developing wound infections after craniotomy, whereas age < 60 years is a protective factor. Clinicians can reduce the occurrence of postoperative wound infections by communicating with patients in advance about the possibility of postoperative wound infections based on these factors, and by doing a good job of preventing postoperative wound infections.

Preoperative nomogram predicting ventriculoperitoneal shunt longevity after initial shunt failure

Background and objectives

Initial shunt failure following ventriculoperitoneal (VP) shunt surgery has a significant impact on the working time of the shunt. However, there are few studies regarding factors affecting VP shunt longevity. Hence, in this study, we aimed to build a nomogram to predict the longevity of the replacement VP shunt in patients with initial shunt failure.

Methods

From 2011 to 2021, 142 patients with initial VP failure who underwent VP shunt revision were enrolled and relevant clinical and demographic factors were analyzed. Univariate and multivariate Cox proportional hazard regression models were used to choose predictors, and a nomogram was constructed using nine independent prognostic variables: sex, age, hydrocephalus type, intensive care unit admission, tracheostomy, decompressive craniectomy, craniotomy, lumbar cisterna drainage, and ventricular drainage. The prediction models' discrimination, accuracy, calibration, and clinical value were evaluated using Harrell's C-index, a calibration plot, and decision curve analysis.

Results

At 1 month, 3 months, and 5 years, the nomogram's C-index was 0.680, 0.708, and 0.694, respectively. The nomogram's calibration plot provided a good fit for the overall prediction over the course of 1 year. Decision curve analysis predicted that 1-3 months after surgery will yield good net benefits between 30 and 50% probability thresholds.

Conclusion

A preoperative nomogram may be an effective tool for assessing VP shunt longevity after initial VP shunt placement.

Diagnostic Accuracy of Procalcitonin in Bacterial Infections of the CNS: An Updated Systematic Review, Meta-Analysis, and Meta-Regression

OBJECTIVES

To evaluate diagnostic accuracy of serum and cerebrospinal fluid (CSF) procalcitonin for diagnosing CNS bacterial infections.

DATA SOURCES

We searched MEDLINE, Cochrane Central Register of Controlled Trials, and International Web of Science databases from January 1, 2016, to September 30, 2022.

STUDY SELECTION

Randomized controlled trials and observational studies, either prospective or retrospective, focusing on procalcitonin as a biomarker for CNS infections.

DATA EXTRACTION

We screened and extracted studies independently and in duplicate. We assessed risk of bias using the revised Quality Assessment for Studies of Diagnostic Accuracy tool. Data for diagnostic sensitivity and specificity were pooled using the bivariate or hierarchical model, as appropriate.

DATA SYNTHESIS

Of 5,347 citations identified, 23 studies were included. Overall, CSF procalcitonin showed slightly higher pooled sensitivity, specificity, and positive likelihood ratio compared with serum procalcitonin. In adults, pooled sensitivity of CSF procalcitonin was 0.89 (95% CI, 0.71-0.96), specificity 0.81 (95% CI, 0.66-0.91); pooled sensitivity of serum procalcitonin was 0.82 (95% CI, 0.58-0.94), specificity 0.77 (95% CI, 0.60-0.89). In children, pooled sensitivity of CSF procalcitonin was 0.96 (95% CI, 0.88-0.99), specificity 0.91 (95% CI, 0.72-0.97); pooled sensitivity of serum procalcitonin was 0.90 (95% CI, 0.75-0.97), specificity 0.83 (95% CI, 0.67-0.92). In post-neurosurgical patients, pooled sensitivity of CSF procalcitonin was 0.82 (95% CI, 0.53-0.95), specificity 0.81 (95% CI, 0.63-0.91); pooled sensitivity of serum procalcitonin was 0.65 (95% CI, 0.33-0.88), specificity 0.61 (95% CI, 0.41-0.78). Logistic regression revealed between-study heterogeneity higher for serum than CSF procalcitonin. For the latter, threshold variability was found as source of heterogeneity.

CONCLUSIONS

In children and critical post-neurosurgical patients, CSF procalcitonin gains superior sensitivity and specificity compared with serum procalcitonin. Overall, CSF procalcitonin appears to have a higher pooled positive likelihood ratio compared with serum procalcitonin.

Demographic profiles and risk factors for mortality in acute meningitis: A nationwide population-based observational study

Aim

Acute meningitis encompasses bacterial, viral (aseptic), fungal, tuberculous, and carcinomatous meningitis. The rate and risks of mortality in each type remain uncertain. This study aimed to elucidate these aspects in each type of meningitis.

Methods

This study utilized Japan's nationwide administrative Diagnosis Procedure Combination (DPC) database. Patients with acute meningitis, treated at 1132 DPC-covered hospitals from 2016 to 2022, were enrolled.

Results

Among 47,366,222 cumulative hospitalized patients, 48,758 (0.10%) were hospitalized with acute meningitis. The types of meningitis were as follows: 10,338 with bacterial, 29,486 with viral/aseptic, 965 with fungal, 678 with tuberculous, and 3790 with carcinomatous meningitis. Bacterial and viral meningitis exhibited bimodal age distributions, with the first peak occurring at 0-9 years. The median onset age was below 50 years only in viral meningitis. The mortality rate was the highest in carcinomatous meningitis (39%), followed by fungal meningitis (21%), and the lowest in viral meningitis (0.61%). Mortality rates increased with age across all meningitis types, but this trend was less prominent in carcinomatous meningitis. The duration from admission to mortality was longer in fungal and tuberculous meningitis compared with other types. Staphylococcus aureus in bacterial meningitis (adjusted odds ratio 1.71; p = 0.0016) and herpes simplex virus in viral meningitis (adjusted odds ratio 1.53; p = 0.0467) exhibited elevated mortality rates.

Conclusion

Distinct demographic profiles and mortality rates were observed among different meningitis types. The high mortality rates in less common types of meningitis emphasize the necessity to further optimize the required diagnostic and treatment strategies.

Evaluation of a clinical pharmacist-led antimicrobial stewardship program in a neurosurgical intensive care unit: a pre-and post-intervention cohort study

Background: Antimicrobial resistance poses a significant challenge in neurosurgical intensive care units (ICU). The excessive use of broad-spectrum antibiotics is closely linked to the emergence and dissemination of drug-resistant bacteria within neurosurgical ICUs. This study assessed the effects of implementing a comprehensive Antimicrobial Stewardship (AMS) program in a neurosurgical ICU setting. Methods: From April 2022 to September 2022, an AMS program was implemented in the neurosurgical ICU. The program involved the regular presence of a pharmacist and an infectious disease physician who conducted prospective audits and provided feedback. To assess the impact of the AMS program, the outcome measures were compared between the AMS period and the 6 months before AMS implementation (pre-AMS period). The primary outcome was the use of antibacterial agents, including anti-pseudomonal beta-lactams (APBLs), polymyxin, and tigecycline. Additionally, the study evaluated the appropriateness of antimicrobial de-escalation and the susceptibility of Gram-negative bacilli to antimicrobial agents. Results: A total of 526 were included during the AMS period, while 487 patients were included in the pre-AMS period. The two groups had no significant differences in disease severity and mortality rates. During the AMS period, there was a notable decrease in the use of APBLs as empiric treatment (43.92% vs. 60.99%, p < 0.001). Multi-drug resistant organism (MDRO) infections decrease significantly during AMS period (11.03% vs. 18.48%, p < 0.001). The number of prescription adjustment increased significantly in all patients (0 item vs. 0 item, p < 0.001) and MDRO-positive patients (3 items vs. 2 items, p < 0.001) during the AMS period. Additionally, appropriate antimicrobial de-escalation for patients with MDRO showed improvement during the AMS period (39.66% vs. 20%, p = 0.001). Polymyxin utilization also decreased during the AMS period (15.52% vs. 31.11%, p = 0.034). Furthermore, the susceptibility of Gram-negative Bacilli isolates to APBLs was significantly higher during the AMS period. Conclusion: Implementing a comprehensive pharmacist-led AMS program led to a decrease in the use of antibacterial agents. This reduction in usage is significant because it can potentially delay the emergence of bacterial resistance.

Surgical site infections after elective craniotomy for brain tumor: a study on potential risk factors and related treatments

BACKGROUND

Surgical site infection (SSI) is a common complication following craniotomy that increases morbidity, mortality, and medical expenses. The objectives of this study were to determine the relevant risk factors associated with SSI after elective craniotomy for brain tumor and analyse the treatments for SSI.

METHODS

A retrospective nested case‒control study was conducted using data from patients who underwent craniotomy for brain tumor resection at the Neurosurgical Oncology Department No. 6 of Beijing Tiantan Hospital, Capital Medical University, between January 2019 and December 2021. Risk factors for SSI were determined using multivariate logistic regression analysis. We analyzed microbiological and related treatment data for different SSI types.

RESULTS

Among 2061 patients who underwent craniotomy for brain tumor, 31 had SSI (1.50%). In the multivariate logistic regression analysis, body mass index (BMI) and operative duration were identified as independent risk factors for SSI. The most common microorganism isolated from SSIs was Staphylococcus epidermidis (22.9%), and drug sensitivity results showed that gram-positive bacteria were sensitive to linezolid, vancomycin and tigecycline, whereas gram-negative bacteria were sensitive to meropenem, cefepime and ceftazidime. Six of the seven patients who underwent bone flap removal due to osteomyelitis were infected with gram-negative bacteria.

CONCLUSIONS

BMI and operative duration were identified as independent risk factors for SSI. Diabetes mellitus, previous ratio therapy, type of incision, recurrence tumor and other risk factors were not found to be associated with the occurrence of SSI in this study.

Risk Factors for External Ventricular Drainage-Related Infection: A Systematic Review and Meta-analysis

Background and Objectives

External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures, but EVD-related infection constitutes a significant health concern. Yet, little consensus identifies the risk factors for the development of EVD-related infection. Therefore, we performed a meta-analysis to systematically summarize existing evidence on the incidence and risk factors for EVD-related infection.

Methods

PubMed, Embase, and the Cochrane Library databases from database inception to February 28, 2022, were searched for all studies investigating the incidence and risk factors for EVD-related infection. Data were assessed by R-4.2.0 software. The meta-analysis was used to calculate pooled odds ratios (OR) and 95% confidence intervals (CI).

Results

A total of 48 studies were included. Among the 29 factors analyzed, statistically significant risk factors were subarachnoid hemorrhage(SAH)/intraventricular hemorrhage(IVH) (OR = 1.48, 95% CI = 1.20-1.82, p < 0.001), concomitant systemic infection (OR = 1.90, 95% CI = 1.34-2.70, p < 0.001), other neurosurgical procedures (OR = 1.76, 95% CI = 1.02-3.04, p = 0.041), change of catheter (OR = 5.05, 95% CI = 3.67-6.96, p < 0.001), bilateral EVDs (OR = 2.25, 95% CI = 1.03-4.89, p = 0.041), (cerebrospinal fluid) CSF leak (OR = 3.19, 95% CI = 2.12-4.81, p < 0.001) and duration of EVD >7 days (OR = 4.62, 95% CI = 2.26-9.43, p < 0.001). The use of silver-coated catheters (OR = 0.57, 95% CI = 0.38-0.87, p = 0.008) and antibiotic-impregnated catheters (OR = 0.60, 95% CI = 0.41-0.88, p = 0.009) might help reduce the risk of infection. No significant difference was indicated in studies evaluating factors like diabetes mellitus (OR = 1.25, 95% CI = 0.90-1.75, p = 0.178), steroids used (OR = 1.52, 95% CI = 0.96-2.4, p = 0.074), prophylactic antibiotics(OR = 0.87, 95% CI = 0.66-1.14, p = 0.308).

Discussion

The meta-analysis of various relevant factors in the onset of EVD-related infection in patients submitted to EVD enabled us to establish a more probable profile of the patients who are more likely to develop it during the treatment.

Treatment of Ventriculitis and Meningitis After Neurosurgery Caused by Carbapenem-Resistant Enterobacteriaceae (CRE): A Challenging Topic

Post-neurosurgical infection is a common complication of neurosurgery, and serious infection can threaten the life of patients. In recent years, the increase in multidrug-resistant bacteria, especially carbapenem-resistant Enterobacteriaceae (CRE), has proved fatal to patients. Although there are a few cases of CRE meningitis and few clinical trials have been carried out, it has attracted increasing attention with the increasing probability of its occurrence, especially considering that there are few successful cases. An increasing number of studies are also looking for the risk factors and clinical symptoms of CRE intracranial infection. In terms of treatment, some new antibiotics are gradually being used in the clinic, but due to the complicated drug-resistant mechanism of CRE and the obstruction of the blood‒brain barrier (BBB), the therapeutic effect is still very poor. In addition, obstructive hydrocephalus and brain abscess caused by CRE meningitis are still important causes of patient death and are also difficult to treat.

Meningitis after elective intracranial surgery: a systematic review and meta-analysis of prevalence

Meningitis is a potential complication of elective intracranial surgery (EIS). The prevalence of meningitis after EIS varies greatly in the literature. The objective of this study was to estimate the overall pooled prevalence of meningitis following EIS. Four databases (PubMed, Scopus, Web of Science, and Embase) were searched to identify relevant studies. Meta-analyses of proportions were used to combine data. Cochran's Q and I² statistics were used to assess and quantify heterogeneity. Additionally, several subgroup analyses were conducted to investigate the source of heterogeneity and examine differences in the prevalence based on variables such as geographical regions, income level, and meningitis type. The meta-analysis included 83 studies (30 959 patients) from 26 countries. The overall pooled prevalence of meningitis after EIS was 1.6% (95% CI 1.1-2.1), with high heterogeneity present (I² = 88%). The pooled prevalence in low- to middle-income countries and high-income countries was 2.7% (95% CI 1.6-4.1) and 1.2% (95% CI 0.8-1.7), respectively. Studies that reported only aseptic meningitis had a pooled prevalence of 3.2% (95% CI 1.3-5.8). The pooled prevalence was 2.8% (95% CI 1.5-4.5) in studies that reported only bacterial meningitis. Similar prevalence rates of meningitis were observed in the subgroups of tumor resection, microvascular decompression, and aneurysm clipping. Meningitis is a rare but not exceptional complication following EIS, with an estimated prevalence of 1.6%.

Brain MRI features of anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis secondary to central nervous system infection in adult patients

BACKGROUND

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis secondary to central nervous system (CNS) infection is a unique subtype of the autoimmune-mediated disease, of which the imaging features are unclear.

PURPOSE

To compare the brain magnetic resonance imaging (MRI) features between the anti-NMDAR encephalitis secondary to CNS infection and that without initial infection.

MATERIAL AND METHODS

A total of 70 adult patients with anti-NMDAR encephalitis were retrospectively enrolled (24 in the post-infection group, 46 in the non-infection-related group). Their clinical and imaging features (lesion distribution, lesion shape, enhancement pattern, brain atrophy) were reviewed and summarized. Lesion distributions were compared between the two groups on lesion probability maps.

RESULTS

The patients with normal brain MRI scans in the post-infection group were less than those in the non-infection related group (29% vs. 63%; P = 0.0113). Among the 24 patients in the post-infection group, visible lesions were shown at the anti-NMDAR encephalitis onset in 17 patients; lesion distribution was more diffuse than the non-infection-related group, showing higher lesion peak probabilities in the bilateral hippocampus, frontal lobe, temporal lobe, insula, and cingulate. The lesions with contrast enhancement were also more common in the post-infection group than the non-infection-related group (7/13 vs. 2/10). Brain atrophy was observed in eight patients in the post-infection group and three in the non-infection-related group.

CONCLUSION

Anti-NMDAR encephalitis secondary to CNS infection has its imaging features-extensive lesion distribution, leptomeningeal enhancement, early atrophy, and necrosis-that could deepen the understanding of the pathophysiology and manifestation of the autoimmune encephalitis besides the classic type.

Risk factors for 90-day all-cause mortality in post-operative central nervous system infections (PCNSIs): A retrospective study of 99 patients in China

Post-operative central nervous system infections (PCNSIs) are serious complications of craniotomy. Many factors, including patient-related, surgical, and postoperative factors, affect the survival of patients with PCNSIs. Timely and effective implementation of antibiotics targeting pathogenic bacteria is crucial to reduce mortality. Metagenomic next-generation sequencing (mNGS) has been used successfully to detect pathogens associated with infectious diseases. This study was designed to evaluate the factors influencing mortality and to explore the application value of mNGS in patients with PCNSIs. We conducted a retrospective study of patients with PCNSIs in our unit from 1/12/2019 to 28/2/2021. Clinical data, cerebrospinal fluid (CSF) parameters, surgical information, and mNGS results were collected. Follow-up telephone calls were made in June 2021 for 90 days survival after discharge. 99 patients were enrolled, and the overall mortality rate was 36.4% (36/99). Kaplan-Meier survival analysis suggested that the risk factors for poor prognosis included age ≥ 53 years, Glasgow Coma scale (GCS) score ≤ 8, CSF/blood glucose ratio (C/B-Glu) ≤ 0.23, 2 or more operations, mechanical ventilation (MV), and non-mNGS test. MV and poor wound healing were independent risk factors for 90 day mortality according to the multivariate Cox proportional hazards model (OR = 6.136, P = .017, OR = 2.260, P = .035, respectively). Among the enrolled patients, causative pathogens were identified in 37. Gram-negative pathogens were found in 22 (59.5%) patients, and the remaining 15 (40.5%) were Gram-positive pathogens. Univariate analysis showed that white cell count and protein and lactate levels in the CSF of the Gram-negative group were higher than those of the Gram-positive group (P < .05). mNGS and conventional microbiological culture were tested in 34 patients, and the positive detection rate of mNGS was 52.9%, which was significantly higher than that of microbiological culture (52.9% vs 26.5%, χ2 = 4.54, P = .033). The mortality rate of PCNSIs is high, and patients with MV and poor wound healing have a higher mortality risk. Gram-negative pathogens were the predominant pathogens in the patients with PCNSIs. mNGS testing has higher sensitivity and has the potential to reduce the risk of mortality in patients with PCNSIs.

Association of Diabetes with Meningitis Infection Risks: A Systematic Review and Meta-Analysis

Background

The Global Burden of Disease Study in 2016 estimated that the global incident cases of meningitis have increased by 320,000 between 1990 and 2016. Current evidence suggests that diabetes may be a prime risk factor for meningitis among individuals, including older adults. However, findings of prior studies on this topic remain inconsistent, making a general conclusion relatively difficult. This study aimed to quantitatively synthesize the literature on the risk of meningitis associated with diabetes and compare the risk across different global regions.

Method

Literature search and study design protocol followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was conducted in PubMed, Web of Science, African Journal Online, and Google Scholar using relevant MESH terms. A random effect model was used to pull effect sizes.

Results

Initial search yielded 772 papers but 756 studies were excluded due to duplicity and not meeting inclusion criteria. In all, 16 papers involving 16847 cases were used. The pulled effect size (ES) of the association between diabetes and meningitis was 2.240 (OR = 2.240, 95% CI = 1.716-2.924). Regional-base analysis showed that diabetes increased the risk of developing meningitis in Europe (OR = 1.737, 95% CI = 1.299-2.323), Asia (OR = 2.192, 95% CI = 1.233-3.898), and North America (OR = 2.819, 95% CI = 1.159-6.855). These associations remained significant in the study design and etiological classe-based subgroup analyses. However, we surprisingly found no studies in Africa or South America.

Conclusion

Diabetes is a risk factor for developing meningitis. Given that no research on this topic came from Africa and South America, our findings should be contextually interpreted. We, however, encourage studies on diabetes-meningitis linkages from all parts of the world, particularly in Africa and South America, to confirm the findings of the present study.

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.

Nomogram Analysis of Clinical Characteristics and Mortality Risk Factor of Non-Fermentative Gram-Negative Bacteria-Induced Post-Neurosurgical Meningitis

Objective

To explore the clinical characteristics of post-neurosurgical meningitis (PNM) patients infected with nonfermenting Gram-negative bacilli (NFGNB) and to evaluate the related mortality risk factors.

Methods

A cohort analysis of PNM patients infected with NFGNB in Beijing Tiantan Hospital and Capital Medical University from 2012.1 to 2020.12. The microbial distribution, antimicrobial sensitivity and genotypes were tested, and potential mortality risk factors were evaluated using Mann–Whitney U or chi-squared tests. Independent risk factors for mortality were established by constructing a logistic model.

Results

A total of 2940 PNM patients were enrolled in this study, of whom 207 (17.1%) were infected with NFGNB. Among these patients, 29 died of NFGNB meningitis, with an overall mortality rate of 14.0%. The top three NFGNBs were Acinetobacter baumannii (105 cases, 50.7%), Pseudomonas aeruginosa (29 cases, 14.0%) and Acinetobacter lwoffii (20 cases, 9.7%). Nomogram analysis revealed that hypertension (OR 4.551, 95% CI: 1.464–14.154, P = 0.009), external ventricular drainage (EVD) (OR 3.944, 95% CI: 1.286–12.095, P = 0.016), and assisted mechanical ventilator (AMV) (OR 6.192, 95% CI: 1.737–22.081, P = 0.005) were independent risk factors for mortality. In addition, antibiotic prophylaxis was shown to play a vital role in NFGNB-induced PNM therapy.

Conclusion

PNM patients infected with NFGNB have a high mortality rate. Hypertension, EVD and AMV were independent mortality risk factors, and clinical attention should be paid to their prevention and treatment.

Prophylactic intraventricular piping method prevents entrapped temporal horn after removal of ventricle trigone meningioma: technical note

BACKGROUND

Entrapped temporal horn (ETH) is one of the critical complications after tumor removal in the lateral ventricle trigone that sometimes becomes life-threatening.

OBJECTIVE

To develop a novel intraoperative method of prophylactic intraventricular piping (PIP) just after tumor removal to prevent ETH.

METHODS

Three patients with meningiomas in the lateral ventricle trigone were treated by a novel intraoperative method of PIP just after tumor removal to prevent ETH. Silicone catheters normally used as ventricular drainage catheters were cut to 5-6 cm length and inserted into the tumor cavity to ensure communication between the temporal horn and the atrium or the body of the lateral ventricle through the piping straddling the trigone.

RESULTS

None of our patients developed ETH during the follow-up period without complications caused by the tube placement.

CONCLUSIONS

PIP might be beneficial to prevent ETH because constant osmotic pressure and constant cerebrospinal fluid pulse wave transmission are maintained between each compartment of the lateral ventricle.

Etiology and Outcomes of Healthcare-Associated Meningitis and Ventriculitis—A Single Center Cohort Study

Healthcare associated meningitis and ventriculitis (HCAMV) are serious complications of neurosurgical procedures. We conducted a retrospective cohort study of patients with HCAMV treated at the University Hospital for Infectious Diseases Zagreb during the 2013–2019 period. A total of 144 patients with 151 episodes of HCAMV were included. The most common indications for neurosurgical procedures were brain tumor, hemorrhage and hydrocephalus. Etiology was identified in 90 (59.6%) episodes (either positive CSF culture or positive PCR), and in other 61 (40.39%) the diagnosis of HCAMV was made based on clinical and CSF parameters, without microbiologic confirmation. Carbapenem-resistant Acinetobacter baumannii was the most common pathogen (15.89%), followed by Staphylococcus aureus (13.91%), Pseudomonas aeruginosa (13.25%) and Coagulase negative staphylococci (7.95%). Overall, 24 (16.3%) patients died, and the majority had adverse outcomes, persistent vegetative state (8, 5.56%) and severe disability (31, 21.53%). The worst clinical outcomes were observed in A. baumannii infections. High rate of complications, the need for external ventricular drainage (re)placement often complicated with nosocomial infections and prolonged stay in intensive care units were observed. Clinicians should be aware of local microbial epidemiology on guiding proper empirical antimicrobial treatment in patients with HCAMV.

Length of preoperative hospital stay is the dominating risk factor for surgical site infection in neurosurgery: A cohort data-driven analysis

Background:

The number of days of preoperative hospital stay (PHS) is a modifiable variable that has shown contradictory surgical site infection (SSI) risk factor results in neurosurgery. We sought to pinpoint the day of PHS length related with a marked increase of risk of SSI.

Methods:

From a tertiary teaching hospital, January 2015–December 2017, prospectively collected nonpercutaneous neurosurgery procedures with standard antibiotic prophylaxis and 1-year follow-up were evaluated. SSI risk factors were assessed through multiple logistic regression models with different thresholds of PHS.

Results:

A total of 1012 procedures were included in the study. Incidence of SSI was 4.4%. The median PHS was higher in those with SSI than in those without (1 day, interquartile range [IQR]: 7 vs. 0 days, IQR: 1, respectively, P = 0.002). By the amount of six days of PHS, this exposure risk past the threshold of significance for impact on wound infection (OR 2.8; CI 1.23–6.39, P = 0.014). Operative time past 4 h (OR 2.11; CI 1.12-3.98; P = 0.021), and in some models, previous surgery at same admission were also identified by multivariate analysis as increasing postoperative SSI risk.

Conclusion:

The gradual increase of the SSI OR associated with longer PHS days was the highest risk factor of SSI in our cohort of patients. Studies directed to reduce this complication should consider the PHS.

Nanopore 16S sequencing enhances the detection of bacterial meningitis after neurosurgery

Objective

Nosocomial bacterial meningitis is one of the major complications after neurosurgery. We performed nanopore 16S amplicon sequencing from cerebrospinal fluid (CSF) to evaluate bacterial meningitis in patients who underwent neurosurgery.

Methods

Among the patients who visited the neurosurgery department of Seoul National University Hospital between July 2017 and June 2020, those with clinically suspected bacterial meningitis were included. 16S rDNA PCR was performed from the CSF, and nanopore sequencing was performed for up to 3 h. The reads were aligned to the BLAST database. In each case, the culture and the 16S rRNA gene amplicon analysis were simultaneously performed and compared with each other, and we retrospectively reviewed the medical records. Genuine infection was determined by the identical results between conventional culture study and the sequencing, or clinically determined in cases with inconsistent results between the two methods.

Results

Of the 285 samples obtained from 178 patients who had 16S rDNA PCR, 41 samples (14.4%) were diagnosed with genuine infection. A total of 56.1% (23/41) of the samples with genuine infection showed a false‐negative culture test. In particular, 16S amplicon sequencing was useful in evaluating patients at the initial tests who had infection with intraventricular hemorrhage (Culture false‐negative rate = 100%), subarachnoid hemorrhage (Culture false‐negative rate = 77.8%), and systemic cancer (Culture false‐negative rate = 100%), which are risk factors for central fever. Moreover, 16S amplicon sequencing could suggest the possibility of persistent bacterial meningitis in empirical antibiotic use.

Conclusion

CSF nanopore 16S sequencing was more effective than conventional CSF culture studies in postoperative bacterial meningitis and may contribute to evidence‐based decisions for antibiotic maintenance and discontinuation.

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.

Machine Learning Approaches-Driven for Mortality Prediction for Patients Undergoing Craniotomy in ICU

OBJECTIVES

We aimed to predict the mortality of patients with craniotomy in ICU by using predictive models to extract the high-risk factors leading to the death of patients from a retrospective a study.

METHODS

Five machine-learning (ML) algorithms were applied for training on mortality predictive models with the data from a surgical intensive care unit (ICU) database of the Fujian Provincial Hospital in China. The accuracy, precision, recall, f1 score and the area under the receiver operator characteristic curve (AUC) were used to evaluate the performance of different models, and the calibration of the model was evaluated by brier score.

RESULTS

We demonstrated that eXtreme Gradient Boosting (XGBoost) was more suitable for the task, demonstrating a AUC of 0.84. We analyzed the feature importance with the Local Interpretable Model-agnostic Explanations (LIME) analysis and further identified the high-risk factors of mortality in ICU through this study.

CONCLUSIONS

This study established the mortality predictive model of patients who had undergone craniotomy in ICU. Identification of the factors that had great influence on mortality has the potential to provide auxiliary decision support for clinical medical staff on their practices.

Role of topical vancomycin in reduction of postoperative infections in head trauma patients: A developing country experience

Background:

Postoperative cranial wound infections are a major cause of morbidity, mortality, and financial burden, especially in developing countries.

Methods:

We prospectively studied 86 patients in a randomized trial; 39 patients received one gram of topical vancomycin powder in the subgaleal space while 47 matched control patients did not. Both groups received identical intraoperative and post-operative care. The primary outcome variable was the postoperative wound infections rate factored by cohort. Secondary outcomes were the timing of infection and the rate of adverse events.

Results:

Adding topical vancomycin was associated with a significantly lower rate of infection than the standard of care alone (2.6% [1/39] vs. 14.9% [7/47], P =.004). No adverse reactions occurred.

Conclusion:

Topical vancomycin is safe, and effective in the prevention of surgical site infections following craniotomy. These findings have broad consequences for neurosurgery practice, especially in developing countries with high incidence of head trauma.

Homologous Escherichia coli Identified in Cerebrospinal Fluid and Bloodstream

Background

Escherichia coli is an opportunistic bacterium that causes a wide range of diseases, such as bloodstream infection and central nervous system infection. The traditional culture-based method to detect E. coli usually takes more than 2 days. The object of this study is to explore the value of metagenomic next-generation sequencing (mNGS) in identifying E. coli from human cerebrospinal fluid. In addition, we investigated the infection source of E. coli through whole genome sequencing and phylogenetic analysis.

Methods

We combined a clinical example to analyze the function of mNGS in pathogen detection from cerebrospinal fluid. NextSeq 550Dx platform was applied for mNGS. Next, whole genome sequencing was performed to obtain the genomic characterization of E. coli. Furthermore, we screened 20 E. coli strains from the National Center for Biotechnology Information and conducted a phylogenetic analysis.

Results

A middle-aged patient who attended our hospital was diagnosed with craniopharyngioma and received surgery. The patient had recurrent fever and persistent lethargy after surgery. Cerebrospinal fluid culture firstly failed to grow the bacteria. Next the cerebrospinal fluid sample was detected by mNGS and the sequence readings of E. coli were identified. Later, E. coli was reported via the second cerebrospinal fluid culture, certifying the result of mNGS. Moreover, we also cultured carbapenem-resistant E. coli from the patient’s bloodstream. Through whole genome sequencing and phylogenetic analysis, we found that the E. coli isolated from cerebrospinal fluid and the bloodstream was 100% homologous, indicating the E. coli central nervous system infection was originated from the bloodstream.

Conclusion

Metagenomic next-generation sequencing is a valuable tool to identify the pathogens from cerebrospinal fluid, and seeking the infection source is of great significance in clinical diagnosis and treatment. Furthermore, carbapenem-resistant E. coli is a serious problem as the cause of bloodstream infection and central nervous system infection, and effective and adequate measures to prevent and control the present circumstance are urgent.

Clinical Features of Post-Operative Nosocomial Meningitis in Adults and Evaluation of Efficiency of Intrathecal Treatment

Background: Post-operative nosocomial meningitis is a critical complication that develops in patients after neurosurgical interventions and operations. Patients and Methods: Data were collected for 65 patients who were diagnosed as having nosocomial meningitis after neurosurgery. The agent profile, clinical and biochemical differences in gram-negative and gram-positive meningitis, and the effectiveness of intrathecal antibiotic administration in cases with carbapenem-resistant gram-negative agents were evaluated. Results: Gram-negative bacteria were isolated in 52.3% of patients. In gram-negative cases of post-operative nosocomial meningitis, white blood cell count (p = 0.015), C-reactive protein (p = 0.001), cerebrospinal fluid leukocyte count (p = 0.0001), and protein (p = 0.0001) were higher, and glucose (p = 0.002) was lower. Concurrent bacteremia (p = 0.041), 14-day mortality (p = 0.022), and 30-day mortality (p = 0.023) were higher in gram-negative cases. Empirical treatment was appropriate in 78.5% of the patients. Seventeen patients (26.2%) received intrathecal antibiotic agents in addition to intravenous antibiotic treatment because of carbapenem-resistant gram-negative bacteria. Nine (53%) of the patients receiving intrathecal therapy had Acinetobacter baumannii as the agent, six had Klebsiella pneumoniae (35.4%), one had Pseudomonas aeruginosa (5.8%), and one had Providencia rettgeri (5.8%). The mean intravenous treatment duration was 21.4 ± 10.6 (4-60) days, and the mean intrathecal treatment duration was 17.6 ± 14.0 (1-51) days. Eleven patients received colistimethate sodium intrathecally (1 × 10 mg/d), three patients received amikacin intrathecally (1 × 10 mg/d), and three patients received gentamicin intrathecally (1 × 10 mg/d). Clinical and microbiologic treatment success was achieved in nine patients (53%). Conclusions: In cases of meningitis caused by carbapenem-resistant agents, intrathecal administration of antibiotic agents such as gentamicin, amikacin, and colistin with limited blood-brain barrier transition in intravenous administration will increase survival. Therefore, intrathecal antibiotic administration should be considered as a part of routine of nosocomial meningitis.

A non-linear ensemble model-based surgical risk calculator for mixed data from multiple surgical fields

BACKGROUND

The misestimation of surgical risk is a serious threat to the lives of patients when implementing surgical risk calculator. Improving the accuracy of postoperative risk prediction has received much attention and many methods have been proposed to cope with this problem in the past decades. However, those linear approaches are inable to capture the non-linear interactions between risk factors, which have been proved to play an important role in the complex physiology of the human body, and thus may attenuate the performance of surgical risk calculators.

METHODS

In this paper, we presented a new surgical risk calculator based on a non-linear ensemble algorithm named Gradient Boosting Decision Tree (GBDT) model, and explored the corresponding pipeline to support it. In order to improve the practicability of our approach, we designed three different modes to deal with different data situations. Meanwhile, considering that one of the obstacles to clinical acceptance of surgical risk calculators was that the model was too complex to be used in practice, we reduced the number of input risk factors according to the importance of them in GBDT. In addition, we also built some baseline models and similar models to compare with our approach.

RESULTS

The data we used was three-year clinical data from Surgical Outcome Monitoring and Improvement Program (SOMIP) launched by the Hospital Authority of Hong Kong. In all experiments our approach shows excellent performance, among which the best result of area under curve (AUC), Hosmer-Lemeshow test ([Formula: see text]) and brier score (BS) can reach 0.902, 7.398 and 0.047 respectively. After feature reduction, the best result of AUC, [Formula: see text] and BS of our approach can still be maintained at 0.894, 7.638 and 0.060, respectively. In addition, we also performed multiple groups of comparative experiments. The results show that our approach has a stable advantage in each evaluation indicator.

CONCLUSIONS

The experimental results demonstrate that NL-SRC can not only improve the accuracy of predicting the surgical risk of patients, but also effectively capture important risk factors and their interactions. Meanwhile, it also has excellent performance on the mixed data from multiple surgical fields.

Impact of Diabetes Mellitus on Adverse Outcomes After Meningioma Surgery

OBJECTIVE

We sought to investigate the association between diabetes mellitus and incidence of adverse outcomes in patients who underwent meningioma surgery.

METHODS

The 2012-2014 National Inpatient Sample database was used. Prolonged length of stay was indicated by values greater than the 90th percentile of the sample. The Fisher exact test and analysis of variance were used to compare demographics, hospital characteristics, comorbidity, and complications among race cohorts. Logistic regression was used to analyze the independent effect of diabetes on adverse outcomes.

RESULTS

After selecting for patients with primary diagnosis of meningioma who underwent a resection procedure, 7745 individuals were identified and divided into diabetic (n = 1518) and nondiabetic (n = 6227) cohorts. Demographics, hospital characteristics, and comorbidities were significantly different among the 2 cohorts. Average length of stay was longer in diabetic patients (8.15 vs. 6.04 days, P < 0.001), and total charges were higher in diabetic patients ($139,462.66 vs. $123,250.71, P < 0.001). Multivariate regression indicated diabetic patients have higher odds of experiencing a complication (odds ratio [OR] 1.442, 95% confidence interval [CI] 1.255-1.656, P < 0.001) and in-hospital mortality (OR 1.672, 95% CI 1.034-2.705, P = 0.036) after meningioma surgery. Analysis of individual postoperative complications revealed that diabetic patients experienced increased odds of pulmonary (OR 1.501, 95% CI 1.209-1.864, P < 0.001), neurologic (OR 1.690, 95% CI 1.383-2.065, P < 0.001), and urinary/renal complications (OR 2.618, 95% CI 1.933-3.545, P < 0.001). In addition, diabetic patients were more likely to have a prolonged length of stay (OR 1.694, 95% CI 1.389-2.065, P < 0.001).

CONCLUSIONS

Diabetes is an important factor associated with complications after meningioma surgery. Preventative measures must be taken to optimize postoperative outcomes in these patients.

Dynamic Curve Analysis of Indicators Related to Lumbar Cistern Drainage for Postoperative Meningitis

OBJECTIVE

To analyze the dynamic curve of cerebrospinal fluid (CSF)-related indices in cases of postoperative meningitis after selective craniotomy and to provide reference data for the clinical treatment with lumbar cistern drainage (LCD).

METHODS

We conducted a retrospective study of LCD placement in 51 patients. Primary outcomes measured included dynamic changes of body temperature before and after intervention and cerebrospinal fluid biochemical parameters over the course of 13 days of catheter placement. We also assessed the bivariate correlation between white blood cell (WBC) count changes, polykaryocyte percentage, body temperature, and daily cerebrospinal fluid drainage volume. Finally, we analyzed the effect of average daily drainage volume, antibiotic choice, and surgical site on WBC count change curves.

RESULTS

After LCD, there was a statistically significant difference (P < 0.01) between the WBC count before drainage and on the fourth day of drainage. There was a negative correlation between the change curve of the WBC count and the change curve of daily drainage volume (r = -0.56). When the daily drainage volume was 250-300 mL/day, the change curve pattern of the WBC count was consistent with the overall trend, and there was no significant difference in the curve of the WBC count between different surgical sites (P > 0.05).

CONCLUSIONS

The WBC count can decrease significantly by day 4 after drainage, and placement of the LCD for 6-7 days is ideal. An average drainage volume of 250-300 mL/day is safe and effective.

Phenotype, molecular characterisation and risk factors for postoperative meningitis caused by ESBL-producing-Enterobacteriaceae: a six years multi-Centre comparative cohort study

BACKGROUND

To determine the phenotype, molecular characterisation and risk factors of postoperative meningitis induced by Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (EPE) in China.

METHODS

We performed a multi-centre comparative cohort study of postoperative meningitis patients infected with Enterobacteriaceae in 4 neurosurgical centres in China from January 2014 to December 2019. Phenotype and molecular characteristics of the isolates were reviewed and tested, and independent risk factors of the EPE meningitis were evaluated by binary logistic regression.

RESULTS

In total, 220 Enterobacteriaceae include 78 EPE were available in this study. 85.6% (67/78) ESBL-related genes were tested, and blaSHV (14.9%) and blaSHV + blaTEM + blaCTX-M-9 (20.9%) were found to be the most frequent mono and combined ESBL-related genes harboured by Enterobacteriaceae. On binary logistic analysis, craniotomy (OR. 2.583, 95% C.I. 1.274-5.235, P = 0.008) and malignancy (OR. 2.406, 95% C.I. 1.299-4.456, P = 0.005) were the associated independent risk factors to meningitis induced by EPE.

CONCLUSIONS

To the best of our knowledge, this is the largest series focusing on risk factors of EPE meningitis which has been conducted in China. Craniotomy and malignancy were independent risk factors for EPE meningitis. The risk factors identified may be further utilized in clinical practice and research to avoid and reduce the mortality in future.

Hypothalamus-Pituitary Dysfunction as an Independent Risk Factor for Postoperative Central Nervous System Infections in Patients With Sellar Region Tumors

OBJECTIVE

The purpose of this study was to verify that hypothalamus-pituitary dysfunction is one of the risk factors for postoperative central nervous system infections (PCNSIs).

METHOD

We performed a retrospective analysis of all patients with sellar region lesions who underwent surgery between January 2016 and November 2019 at Peking Union Medical College Hospital. In total, 44 age- and sex-matched controls were enrolled. Univariate and multivariate analyses were performed to identify risk factors for PCNSIs.

RESULT

We enrolled 88 patients, 44 of whom had PCNSIs. Surgical approach (TCS) (P<0.001), previous surgery on the same site (P=0.001), intraoperative cerebral spinal fluid (CSF) leakage (P<0.001), postoperative adrenal insufficiency (P=0.017), postoperative DI (P=0.004) and the maximum Na⁺ levels(<0.001) correlated significantly with PCNSIs. Multivariate analysis showed that Surgery approach (TCS)(OR: 77.588; 95%CI: 7.981-754.263; P<0.001), intraoperative CSF leakage (OR: 12.906; 95%CI: 3.499-47.602; P<0.001), postoperative DI (OR: 6.999; 95%CI:1.371-35.723; P=0.019) and postoperative adrenal insufficiency (OR: 6.115; 95%CI: 1.025-36.469; P=0.047) were independent influencing factors for PCNSIs.

CONCLUSION

TCS, intraoperative CSF leakage, postoperative DI and postoperative adrenal insufficiency are risk factors for PCNSIs in patients with sellar region tumors.

[Risk factors of nosocomial meningitis in neurological intensive care unit. Results of a five-year prospective study]

Nosocomial meningitis (NM) is a serious complication in neurosurgery. Understanding the risk factors of nosocomial meningitis is important for their prevention.

OBJECTIVE

To determine the main risk factors of NM in neurological intensive care unit.

MATERIAL AND METHODS

A prospective study included all patients (n=2140) treated at the neurological intensive care unit for more than 48 hours between October 1, 2010 and October 31, 2015. Cases of nosocomial meningitis were registered. We analyzed risk factors in 2 groups of patients (with and without NM).

RESULTS AND DISCUSSION

The incidence of NM in neurological intensive care unit was 8.4% (95% CI 6.8-10.0) (n=180). Relative risk of NM under external ventricular drainage was 3.98 (99 cases of NM, p<0.05). Relative risk of NM in patients with CSF leakage (including nasal CSF leakage after transsphenoidal surgery) was 5.2 (49 cases of NM, p<0.05). The incidence of nosocomial meningitis was significantly higher among patients with surgery time ≥8 hours (17.68%, p<0.01). Nosocomial meningitis was also significantly more common after redo surgery (13.07%, p<0.05). Insertion of intracranial pressure sensor was not a significant risk factor of NM. The risk of meningitis was 2.67% if the above-mentioned factors were absent. Extracranial factors are not specific for NM. No significant relationship between certain neurosurgical disease and NM was found.

CONCLUSION

We found higher risk of NM in ICU patients with the following factors: external ventricular drainage, CSF leakage, redo surgery and surgery time.

Sepsis and septic shock after craniotomy: Predicting a significant patient safety and quality outcome measure

OBJECTIVES

Sepsis and septic shock are important quality and patient safety metrics. This study examines incidence of Sepsis and/or septic shock (S/SS) after craniotomy for tumor resection, one of the most common neurosurgical operations.

METHODS

Multicenter, prospectively collected data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was used to identify patients undergoing craniotomy for tumor (CPT 61510, 61521, 61520, 61518, 61526, 61545, 61546, 61512, 61519, 61575) from 2012-2015. Univariate and multivariate logistic regression models were used to identify risk factors for S/SS.

RESULTS

There were 18,642 patients that underwent craniotomy for tumor resection. The rate of sepsis was 1.35% with a mortality rate of 11.16% and the rate of septic shock was 0.65% with a 33.06% mortality rate versus an overall mortality rate of 2.46% in the craniotomy for tumor cohort. The 30-day readmission rate was 50.54% with S/SS vs 10.26% in those without S/SS. Multiple factors were identified as statistically significant (p <0.05) for S/SS including ascites (OR = 33.0), ventilator dependence (OR = 4.5), SIRS (OR = 2.8), functional status (OR = 2.3), bleeding disorders (OR = 1.7), severe COPD (OR = 1.6), steroid use (OR = 1.6), operative time >310 minutes (OR = 1.5), hypertension requiring medication (OR = 1.5), ASA class ≥ 3 (OR = 1.4), male sex (OR = 1.4), BMI >35 (OR = 1.4) and infratentorial location.

CONCLUSIONS

The data indicate that sepsis and septic shock, although uncommon after craniotomy for tumor resection, carry a significant risk of 30-day unplanned reoperation (35.60%) and mortality (18.21%). The most significant risk factors are ventilator dependence, ascites, SIRS and poor functional status. By identifying the risk factors for S/SS, neurosurgeons can potentially improve outcomes. Further investigation should focus on the creation of a predictive score for S/SS with integration into the electronic health record for targeted protocol initiation in this unique neurosurgical patient population.

Postoperative empyema following chronic subdural hematoma surgery: Clinically based medicine

INTRODUCTION

Subdural empyema (SDE) is a rare complication of chronic subdural hematoma (CSDH) surgery. We introduced antibiotic prophylaxis (AP) for this procedure in 2014 following a morbidity-mortality conference (MMC) in our department. We report the results of retrospective data analysis to assess the effect of systematic AP and to identify risk factors for SDE.

MATERIAL AND METHODS

Two hundred eight patients were recruited between January 2013 and December 2015; 5 were excluded for incomplete data: 107 without and 96 with AP (n=203). SDE was confirmed by clinical examination, imaging and bacteriological analysis. Comparisons between AP-(no cefuroxime) and AP+ (cefuroxime) groups were made with Chi² test and Student's t-test.

RESULTS

One empyema was found in each group, indicating that AP had no effect (P=1). The only criterion associated with SDE for these two patients was a greater number of reoperations for CSDH recurrence (P=0.013).

DISCUSSION

The incidence of postoperative empyema was 1%, similar to the range of 0.2%-2.1% reported in the literature. This rare incidence explains why we found no significant effect of AP. The medical decision taken at the MMC did not help to reduce the rate of postoperative SDE. MMCs can help to define factors associated with adverse surgical events and identify opportunities for improvement.

CONCLUSION

AP, introduced after an MMC, did not impact SDE rates. In practice, AP should be required only in case of reoperation for CSDH recurrence. However, we still continue to use AP following the MMC considering different parameters discussed in the manuscript.

Longitudinal Analysis of Risk Factors for Clinical Outcomes of Enterobacteriaceae Meningitis/Encephalitis in Post-Neurosurgical Patients: A Comparative Cohort Study During 2014-2019

Purpose

Our study is a retrospective observational study conducted in one of the largest clinical centers of neurosurgery in China. We aimed to investigate the antimicrobial susceptibility patterns of the Enterobacteriaceae isolates responsible for nosocomial meningitis/encephalitis in post-neurosurgical patients. Meanwhile, we tried to evaluate the risk factors for mortality following Enterobacteriaceae meningitis/encephalitis.

Patients and Methods

Medical data on clinical characteristics, antibiotic susceptibilities, and mortality were reviewed until patients’ discharge or death in the hospital. Data for a total of 164 cerebrospinal fluid (CSF) infection cases due to Enterobacteriaceae after neurosurgery were collected between January 2014 and November 2019 in order to identify risk factors affecting the outcome. Kaplan–Meier survival analysis and multivariable Cox proportional hazard models were applied.

Results

In this study, a total of 2416 neurosurgical meningitis/encephalitis cases were reported between 2014 and 2019. Enterobacteriaceae accounted for 7.3% (176/2416) of all the bacterial infections. Of them, 164 Enterobacteriaceae isolates were available to divide into two groups according to the final outcome of whether the patient died or survived. In total, 38 patients died (23.2%) and 126 patients survived (76.8%). The most frequent infecting species was Klebsiella pneumoniae (47.0%, 77/164). Fourteen-day and 30-day mortality rates were 7.9% (13/164) and 15.2% (25/164). Kaplan–Meier survival analysis revealed that the risk factors of Enterobacteriaceae meningitis/encephalitis that resulted in poor outcomes included comorbidities, Glasgow Coma Scale (GCS) score, sepsis, intensive care unit (ICU) admission, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, and ventilation. A GCS score of less than or equal to 8 (P=0.04, HR 2.562) was identified to be a significant risk factor for mortality according to the multivariable Cox proportional hazards model.

Conclusion

In-hospital mortality caused by Enterobacteriaceae meningitis/encephalitis in neurosurgery was high. A GCS score of ≤8 was an independent risk factor for mortality following Enterobacteriaceae meningitis/encephalitis in post-neurosurgical patients.

Clinical application and evaluation of metagenomic next-generation sequencing in suspected adult central nervous system infection

BACKGROUND

Accurate etiology diagnosis is crucial for central nervous system infections (CNS infections). The diagnostic value of metagenomic next-generation sequencing (mNGS), an emerging powerful platform, remains to be studied in CNS infections.

METHODS

We conducted a single-center prospective cohort study to compare mNGS with conventional methods including culture, smear and etc. 248 suspected CNS infectious patients were enrolled and clinical data were recorded.

RESULTS

mNGS reported a 90.00% (9/10) sensitivity in culture-positive patients without empirical treatment and 66.67% (6/9) in empirically-treated patients. Detected an extra of 48 bacteria and fungi in culture-negative patients, mNGS provided a higher detection rate compared to culture in patients with (34.45% vs. 7.56%, McNemar test, p < 0.0083) or without empirical therapy (50.00% vs. 25.00%, McNemar test, p > 0.0083). Compared to conventional methods, positive percent agreement and negative percent agreement was 75.00% and 69.11% separately. mNGS detection rate was significantly higher in patients with cerebrospinal fluid (CSF) WBC > 300 * 10⁶/L, CSF protein > 500 mg/L or glucose ratio ≤ 0.3. mNGS sequencing read is correlated with CSF WBC, glucose ratio levels and clinical disease progression.

CONCLUSION

mNGS showed a satisfying diagnostic performance in CNS infections and had an overall superior detection rate to culture. mNGS may held diagnostic advantages especially in empirically treated patients. CSF laboratory results were statistically relevant to mNGS detection rate, and mNGS could dynamically monitor disease progression.

Effect of Empiric Treatment of Asymptomatic Bacteriuria in Neurosurgical Trauma Patients on Surgical Site and Clostridium difficile Infection

BACKGROUND

Although empiric treatment of urinary tract colonized patients remains a frequent practice in neurosurgery, the value of this practice remains debatable.

OBJECTIVE

To analyze the effect of screening and treatment of bacteriuria on surgical site infections, incidence of Clostridium difficile, and mortality in neurosurgical trauma patients.

METHODS

Database queries and direct patient chart reviews were used to gather patient chart data. T-tests, chi-square tests, binary logistic regressions, and propensity matched cohorts comparisons were performed.

RESULTS

A total of 3563 admitted neurosurgical trauma patients were identified over an 8 yr period (1524 cranial, 1778 spinal, and 261 combined craniospinal diagnoses). Nine hundred ninety-one patients underwent an operative neurosurgical procedure. Urinalysis was significantly associated with antibiotics exposure in both operative and nonoperative patients (P < .001). Operative patients treated with empiric antibiotics did not have a reduced risk of wound infection (P = .21), including in a propensity matched cohort (P = .52). Patients treated with empiric antibiotics had significantly increased rates of C. difficile infection (P < .001). At last follow-up, neurosurgical trauma patients that developed C. difficile had an increased risk of death (P < .005); antibiotic exposure and death were also significantly associated (P = .018). The association of C. difficile with empiric antibiotics remained significant in a propensity-matched cohort (P = .0024).

CONCLUSION

The routine use of urinalysis and empiric urinary antibiotics for bacteriuria in neurosurgical trauma patients without urinary symptoms increases risk of exposure to antibiotics does not decrease rates of wound infection, and is associated with increased rates of C. difficile infection and death.

Risk Factors of External Ventricular Drainage-Related Infections: A Retrospective Study of 147 Pediatric Post-tumor Resection Patients in a Single Center

Background: External ventricular drainage (EVD) is common after brain surgery. However, the incidence of EVD-related infection (ERI) is still relatively high and can increase morbidity and mortality.

Objective: The objective of this study was to analyze ERI factors in pediatric population post-brain tumor surgery.

Methods: From January 2016 to December 2017, 147 patients <18 years old underwent tumor removal at Beijing Tiantan Hospital and had postoperative EVD. We recorded basic demographic data as well as several risk factors. We then analyzed whether these factors were related to ERI.

Results: Patients with a preoperative ventriculo-peritoneal (V-P) shunt, those with longer operation time, those who received blood transfusion, those with more frequent cerebrospinal fluid (CSF) sampling, and those with longer indwelling time of EVD had higher risks of infection (p < 0.05). Logistic regression analysis confirmed that a preoperative V-P shunt, operative duration, intraoperative blood transfusion, frequency of CSF sampling, and EVD duration were correlated with postoperative ERI (p < 0.05).

Conclusion: EVD should be removed as soon as possible and any unnecessary procedures should be avoided to reduce the infection rate. However, prophylactic treatment should be given in case patients do not meet the indication for EVD removal.

Risk factors for postoperative meningitis after microsurgery for vestibular schwannoma

OBJECTIVE

Meningitis after microsurgery for vestibular schwannoma (VS) is a severe complication that results in high morbidity. However, few studies have focused on meningitis after VS surgery. The purpose of this study was to identify the risk factors for meningitis after VS surgery.

METHODS

We performed a retrospective analysis of all VS patients who underwent microsurgery and survived for at least 7 days after surgery, between 1 June 2015 and 30 November 2018 at West China Hospital of Sichuan University. Univariate and multivariate analyses were performed to identify the risk factors for postoperative meningitis (POM).

RESULTS

We enrolled 410 patients, 27 of whom had POM. Through univariate analysis, the factors of hydrocephalus (p = 0.018), Koos grade IV (p = 0.04), operative duration > 3 hours (p = 0.03) and intraoperative bleeding volume ≥400 ml (p = 0. 02) were significantly correlated with POM. The multivariate analysis showed that Koos grade IV (p = 0.04; OR = 3.19; 95% CI 1.032-3.190), operation duration > 3 hours (p = 0.03; OR = 7.927; 95% CI 1.043-60.265), and intraoperative bleeding volume ≥ 400 ml (p = 0.02; OR = 2.551; 95% CI 1.112-5.850) were the independent influencing factors of POM.

CONCLUSIONS

Koos grade IV, operation duration > 3 hours, and intraoperative blood loss ≥ 400 ml were identified as independent risk factors for POM after microsurgery for VS. POM also caused a prolonged hospital stay.

Risk factors for surgical site infection after craniotomy: a prospective cohort study

Background

Although surgical site infection after craniotomy (SSI-CRAN) is a serious complication, risk factors for its development have not been well defined. We aim to identify the risk factors for developing SSI-CRAN in a large prospective cohort of adult patients undergoing craniotomy.

Methods

A series of consecutive patients who underwent craniotomy at a university hospital from January 2013 to December 2015 were prospectively assessed. Demographic, epidemiological, surgical, clinical and microbiological data were collected. Patients were followed up in an active post-discharge surveillance programm e for up to one year after surgery. Multivariate analysis was carried out to identify independent risk factors for SSI-CRAN.

Results

Among the 595 patients who underwent craniotomy, 91 (15.3%) episodes of SSI-CRAN were recorded, 67 (73.6%) of which were organ/space. Baseline demographic characteristics were similar among patients who developed SSI-CRAN and those who did not. The most frequent causative Gram-positive organisms were Cutibacterium acnes (23.1%) and Staphylococcus epidermidis (23.1%), whereas Enterobacter cloacae (12.1%) was the most commonly isolated Gram-negative agent. In the univariate analysis the factors associated with SSI-CRAN were ASA score > 2 (48.4% vs. 35.5% in SSI-CRAN and no SSI-CRAN respectively, p = 0.025), extrinsic tumour (28.6% vs. 19.2%, p = 0.05), and re-intervention (4.4% vs. 1.4%, p = < 0.001). In the multivariate analysis, ASA score > 2 (AOR: 2.26, 95% CI: 1.32–3.87; p = .003) and re-intervention (OR: 8.93, 95% CI: 5.33–14.96; p < 0.001) were the only factors independently associated with SSI-CRAN.

Conclusion

The risk factors and causative agents of SSI-CRAN identified in this study should be considered in the design of preventive strategies aimed to reduce the incidence of this serious complication.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0525-3) contains supplementary material, which is available to authorized users.

Enterococcal Meningitis/Ventriculitis: A Tertiary Care Experience

Context:

Enterococcal meningitis is very rare among bacterial meningitis and has variable clinical outcomes.

Aims:

The purpose of the current study is to evaluate clinical features, therapeutic options with susceptibility profile, and outcomes of enterococcal meningitis in a tertiary care hospital.

Settings and Design:

We retrospectively reviewed medical records of all patients with enterococcal meningitis over the periods of 4 years.

Subjects and Methods:

The clinical and laboratory data of all patients with enterococcal meningitis were evaluated between 2013 and 2016.

Results:

Six cases of enterococcal meningitis were found (three infant and three adults). All patients developed meningitis after neurosurgical procedures, and majority of patients (four out of six) had central nervous system (CNS) devices in situ at the time of development of meningitis. The causative organism isolated from cerebrospinal fluid (CSF) culture of all patients was Enterococcus species only. All Enterococcus spp. were resistant to ampicillin, Amoxicillin-clavulanate, and oxytetracycline and two isolates were also resistant to vancomycin. Four patients with vancomycin-sensitive Enterococcus spp. were treated with vancomycin alone for mean periods of 18 days (14–21 days). One patient with vancomycin-resistant Enterococcus (VRE) meningitis was treated with linezolid alone, and another one requires combination with rifampicin to achieve microbiological clearance of CSF. CNS devices were removed in all patients. No mortality was reported in current case series.

Conclusions:

Enterococcal meningitis is very uncommon, mostly associated with neurosurgical intervention. Early treatment is associated with favorable outcomes. Removal of CNS devices is recommended to achieve a clinical cure.

Myroides odoratus Central Nervous Infection in a Postneurosurgery Patient

The organisms belonging to the genus Myroides are ubiquitously present in the environment and have been implicated in infections in immunocompromised patients. We report the recent isolation of Myroides odoratus from the cerebrospinal fluid (CSF) of a patient with anaplastic astrocytoma in the right frontal lobe who had undergone a supratentorial craniectomy for a recurrent right frontal tumor. The organism was identified by the VITEK-2 automated identification system (BioMérieux, Marcy-l'Étoile, France) in addition to microscopic morphology, cultural characteristics, and biochemical tests. The recovery of pure culture of M. odoratus from CSF culture and the patient's clinical response to treatment with cefoperazone–sulbactam support its potential etiological role. M. odoratus can be a causative agent of postneurosurgery central nervous system infection and is amenable to treatment with appropriate antibiotics.

Guidelines for Antibiotic Prescription in Intensive Care Unit

How to cite this article: Khilnani GC, Zirpe K, Hadda V, Mehta Y, Madan K, Kulkarni A, Mohan A, Dixit S, Guleria R, Bhattacharya P. Guidelines for Antibiotic Prescription in Intensive Care Unit. Indian Journal of Critical Care Medicine 2019;23 (Suppl 1):1-63.

Effect of Staphylococcal Decolonization Regimen and Change in Antibiotic Prophylaxis Regimen on Incidence of Postcraniotomy Aseptic Meningitis

OBJECTIVE

To study the effect of a staphylococcal decolonization regimen (SDR) and change in antibiotic prophylaxis regimen on postoperative meningitis (bacterial and aseptic) rates in patients undergoing elective cranial surgery.

METHODS

Data on elective craniotomy (supratentorial and infratentorial) were collected retrospectively for a total of 4 years-2 years before (2011-2012; group A) and 2 years after (2014-2015; group B) initiation of a SDR and a change in the antibiotic prophylaxis regimen (from chloramphenicol to ceftriaxone) in a neurosurgical unit of a tertiary care hospital. The SDR consisted of a 4% chlorhexidine scrub bath once a day and 10% betadine ointment application intranasally twice daily for ≥2 days before surgery.

RESULTS

A total of 1349 patients (GROUP A, n = 622; group B, n = 727) were included in the present study, of whom 806 (59.7%) were males. Of the 1349 patients, 43 (3.2%) developed postoperative meningitis. Of these 43 patients, 8 (0.6%) had bacterial meningitis (BM) and 35 (2.6%) had aseptic meningitis (AM). A reduction occurred in the incidence of both BM and AM in group B; however, the reduction was statistically significant only for AM (P = 0.48 for BM; P = 0.019 for AM). Multivariate analysis showed that the initiation of an SDR conferred a significant protective effect against developing postoperative AM (relative risk, 0.31; 95% confidence interval, 0.14-0.70; P = 0.005).

CONCLUSIONS

Our data showed that the incidence of AM can be reduced with an SDR and appropriate antibiotic prophylaxis. These findings lend support to the suspicion that AM might be a form of low-grade BM possibly due to a staphylococcal infection.

Predictors Associated With Post-Traumatic Hydrocephalus in Patients With Head Injury Undergoing Unilateral Decompressive Craniectomy

Objective

Post-traumatic hydrocephalus (PTH) makes recovery from head trauma after decompression more complicated and is associated with high risks of clinical deterioration and poor outcomes. The aim of this study was to verify the predictors associated with the development of PTH in patients with head injury undergoing unilateral decompressive craniectomy (DC).

Methods

Among traumatic brain injury (TBI) patients who underwent unilateral DC between January 2013 and December 2016, the clinical medical records, radiological information, and changes of patients’ conditions in the 3-month after injury were reviewed retrospectively.

Results

183 TBI patients after unilateral DC were analyzed, and 50 (27.32%) of them suffered PTH based on head CT scans. Univariate and multivariable analyses revealed that older age (p = 0.002), the Glasgow Coma Scale (GCS) score at admission (p < 0.001), intraventricular hemorrhage (IVH; p = 0.008), post-traumatic cerebral infarction (PCI; p = 0.007), and postoperative meningitis (p = 0.016) were independent predictors for the hydrocephalus after DC. Receiver operating characteristic curves were created and the area under the curve (AUC) were calculated to further assess the accuracy of the variables for predicting PTH. The AUC was 0.836 for the combined all five independent factors (95% confidence interval: 0.775–0.887).

Conclusion

TBI patients who undergo unilateral DC with advanced age, lower GCS score at admission, coexisting IVH, PCI, and/or postoperative meningitis should be closely monitored at follow-up assessments for earlier prediction of PTH.

Increase of Meningitis Risk in Stroke Patients in Taiwan

Background and purpose

The blood–brain barrier (BBB) not only provides a physical obstruction but also recruits and activates neutrophils in cases of infection. Hemorrhagic or ischemic stroke reportedly induces the disruption of the BBB. However, few studies have reported a correlation between the incidence of meningitis in patients with a history of stroke. This study tested the hypothesis that patients with a history of stroke may be more vulnerable to meningitis.

Methods

Stroke and age-matched comparison (n = 29,436 and 87,951, respectively) cohorts were recruited from the Taiwan National Health Insurance database (2000–2011). Correlations between the two cohorts were evaluated by Cox proportional hazard regression model, Kaplan–Meier curve, and log-rank tests.

Results

The incidence of meningitis was higher in the stroke cohort compared to that in the comparison cohort [hazard ratio (HR), 2.89; 95% confidence interval (CI), 2.23–3.74, p < 0.001]. After adjusting for age, sex, and comorbidities, the estimated HR in the stroke cohort was 2.55-fold higher than that in the comparison cohort (CI, 1.94–3.37; p < 0.001). Notably, patients who had experienced hemorrhagic stroke had a higher incidence rate of meningitis than those with a history of ischemic stroke, except for patients older than 75 years (incidence rates in hemorrhagic/ischemic stroke patients, 3.14/1.48 in patients younger than 45 years, 1.52/0.41 in 45- to 64-year group, 1.15/0.90 in 65- to 74-year group, 0.74/0.93 in patients older than 75 years). Moreover, stroke patients who had undergone head surgery had the highest meningitis risk (adjusted HR, 8.66; 95% CI, 5.55–13.5; p < 0.001) followed by stroke patients who had not undergone head surgery (adjusted HR, 2.11; 95% CI, 1.57–2.82; p < 0.001).

Conclusion

Our results indicated that stroke patients have higher risks of meningitis. Compromised BBB integrity in stroke patients may lead to increased vulnerability to infectious pathogens. In summary, our study provided new evidence of the clinical relationship between stroke and meningitis, and our findings suggest the need for precautions to prevent meningitis in stroke patients.

Impact of Operating Room Environment on Postoperative Central Nervous System Infection in a Resource-Limited Neurosurgical Center in South Asia

BACKGROUND

Postoperative central nervous system infections (PCNSIs) are serious complications following neurosurgical intervention. We previously investigated the incidence and causative pathogens of PCNSIs at a resource-limited, neurosurgical center in south Asia. This follow-up study was conducted to analyze differences in PCNSIs at the same institution following only one apparent change: the operating room air filtration system.

METHODS

This was a retrospective study of all neurosurgical cases performed between December 1, 2013, and March 31, 2016 at our center. Providers, patient demographic data, case types, perioperative care, rate of PCNSI, and rates of other complications were reviewed. These results were then compared with the findings of our previous study of neurosurgical cases between June 1, 2012, and June 30, 2013.

RESULTS

All 623 neurosurgical operative cases over the study period were reviewed. Four patients (0.6%) had a PCNSI, and no patients had a positive cerebrospinal fluid (CSF) culture. In the previous study, among 363 cases, 71 patients (19.6%) had a PCNSI and 7 (1.9%) had a positive CSF culture (all Gram-negative organisms). The differences in both parameters are statistically significant (P < 0.001). Between the 2 studies, there was no change in treatment providers, case types, case durations, antibiotic administration practices, and patient demographics.

CONCLUSIONS

The rates of PCNSI and positive CSF culture were significantly lower in our present cohort compared with the cohort in our previous study. The sole apparent change involves the air filtration system inside the neurosurgical operating rooms; this environmental change occurred during the 5 months between the 2 studies. This study demonstrates the impact of environmental factors in reducing infections.