Diagnostic accuracy of cerebrospinal fluid gram stain in children with suspected bacterial meningitis

Empowering nurses for effective diagnostic stewardship: An initiative to address anti-microbial resistance

AIM

This study aimed to evaluate nurses' baseline understanding of diagnostic stewardship (DS) principles and the impact of an educational intervention on their knowledge and practices.

BACKGROUND

Antimicrobial resistance (AMR), driven by inappropriate antibiotic use, is a critical global health threat. Effective antimicrobial stewardship (AMS) requires integrating DS to ensure accurate diagnoses through proper test requisition, specimen handling and timely reporting. However, understanding and implementation of DS remains poor in general, contributing to inappropriate antibiotic use. Nurses play a crucial role in DS, yet their potential is underused, highlighting the need for targeted educational interventions.

DESIGN

A quasi-experimental pre-post study conducted from September 2022 to March 2023.

METHODS

A gap analysis assessed nurses' baseline knowledge of DS informing the development of an online training program. In the intervention phase, pre-and post-assessments measured knowledge improvements after the intervention.

RESULTS

In phase 1, 310 out of 517 nurses completed the gap analysis, with an average score of 6.59 out of 20 (range: 2-13; median score: 6.5). In phase 2, 228 of 613 nurses completed both pre- and post-tests, showing a significant improvement in scores from 4.69 (median 5), in pre-test to 6.22 (median 6) in post-test.

CONCLUSION

The educational intervention significantly enhanced nurses' knowledge of AMR, specimen selection, culture indications and collection techniques. Sustained training is vital to strengthen diagnostic practices, reduce inappropriate antimicrobial use and combat AMR.

Test Characteristics of Cerebrospinal Fluid Gram Stain to Identify Bacterial Meningitis in Infants Younger Than 60 Days

ABSTRACT

In our cohort of 20,947 infants aged 60 days or younger, cerebrospinal fluid Gram stain had a sensitivity of 34.3% (95% confidence interval, 28.1%-41.1%) and a positive predictive value of 61.4% (95% confidence interval, 52.2%-69.8%) for positive cerebrospinal fluid culture, suggesting that Gram stain alone may lead to both underdiagnosis and overdiagnosis of bacterial meningitis.

Point-of-care cerebrospinal fluid Gram stain for the management of acute meningitis in adults: a retrospective observational study

Background

Gram stain of cerebrospinal fluid (CSF) is widely used in the diagnosis of acute meningitis, however, it is often conducted in the laboratory, as only some hospitals have access to point-of-care Gram stain (PCGS). The purpose of this study was to demonstrate the clinical impact and utility of PCGS in diagnosing and treating both bacterial and aseptic meningitis in adults.

Methods

This was a hospital-based, retrospective observational study at a referral center in Okinawa, Japan. We reviewed the records of all patients aged 15 years or older who were admitted to the Division of Infectious Diseases between 1995 and 2015 and finally diagnosed with bacterial (n = 34) or aseptic meningitis (n = 97). For bacterial meningitis, we compared the treatments that were actually selected based on PCGS with simulated treatments that would have been based on the Japanese guidelines. For aseptic meningitis, we compared the rates of antibiotic use between real cases where PCGS was available and real cases where it was not.

Results

PCGS was the most precise predictor for differentiating between bacterial and aseptic meningitis (sensitivity 91.2%, specificity 98.9%), being superior in this regard to medical histories, vital signs and physical examinations, and laboratory data available in the emergency room (ER). In bacterial meningitis, PCGS reduced the frequency of meropenem use (1/34 = 3.0%) compared with simulated cases in which PCGS was not available (19/34 = 55.9%) (p< 0.001). In aseptic meningitis cases, the rate of antibiotic administration was lower when PCGS was used (38/97 = 39.2%) than when it was not (45/74 = 60.8%) (p = 0.006).

Conclusions

PCGS of CSF distinguishes between bacterial and aseptic meningitis more accurately than other predictors available in the ER. Patients with bacterial meningitis are more likely to receive narrower-spectrum antimicrobials when PCGS is used than when it is not. PCGS of CSF thus can potentially suppress the empiric use of antimicrobials for aseptic meningitis.

Clinical utility of anaerobic culture of cerebrospinal fluid

Anaerobic meningitis is a rare serious clinical condition which mainly affects vulnerable populations and patients with predisposing factors such as head trauma, prior neurosurgical procedures or implantable medical devices such as ventriculoperitoneal shunts or ventricular drains. In this study we retrieved data from aerobic and anaerobic cultures of cerebrospinal (CSF) or ventricular fluid ordered over a 5 year period at our institution. A total of 8868 aerobic and 594 anaerobic cultures were performed from 2013 to 2017. 24/594 (4%) anaerobic cultures from 14 patients were positive for anaerobes. Only 3 of those patients were diagnosed clinically with anaerobic meningitis, each with predisposing factors, while anaerobes (Cutibacterium acnes and Clostridium perfringens) recovered from the remaining 21 patients were regarded as contaminants. 129/8868 (1.45%) aerobic CSF cultures were positive for anaerobes. 120/129 (93%) cultures recovered C. acnes while non-C. acnes anaerobes were recovered in the remaining 9 cultures and were deemed to be contaminants. In the majority of situations, recovery of C. acnes from CSF or ventricular fluid was regarded as contamination. Our cohort included 18 patients with a ventriculoperitoneal shunt or ventricular drain, 17 of whom had C. acnes recovered from either aerobic or anaerobic culture, and 10 were treated with targeted antibiotics and surgical replacement of the shunt or drain. Anaerobic culture of the CSF or ventricular fluid aided in identification of two patients with anaerobic meningitis and an additional two patients with shunt infection. Anaerobe culture of CSF is important in identification of anaerobic meningitis, as growth of anaerobes other than C. acnes is rare from aerobic CSF culture.

Nocardia intracranial mycotic aneurysm associated with proteasome inhibitor

We report a case of Nocardia farcinica ruptured intracranial mycotic aneurysm associated with bortezomib and corticosteroid treatment in a multiple myeloma patient. The patient was treated with trimethoprim-sulfamethoxazole and moxifloxacin together with surgical repairment of intracranial mycotic aneurysm.

Risk Classification for Enteroviral Infection in Children With Meningitis and Negative Gram Stain

OBJECTIVES

Enterovirus is the most common cause of aseptic meningitis in children. This study aimed at identifying baseline variables associated with a positive cerebrospinal fluid (CSF) Enterovirus polymerase chain reaction (PCR) to aid clinicians in targeting patients who could be tested and treated as outpatients.

METHODS

We performed a retrospective review of children (2 months to 17 years old) admitted to the Children's Memorial Hermann Hospital in Houston, TX, between January 2005 and December 2010 with symptoms of meningitis, CSF white cell count of greater than 5 cells/mm, and a negative CSF Gram stain, who had a CSF Enterovirus PCR.

RESULTS

One hundred thirty-seven children were reviewed; median age was 4.7 (0.1-17.1) years, and 79 (58%) were male. Fifty patients (37%) had positive CSF Enterovirus PCR. Only 13 (15%) of the Enterovirus PCR-negative patients had an identifiable etiology. All patients were hospitalized. The mean hospital stay for patients with Enterovirus was 2.9 days; 88% received empiric antibiotics. Rates of antibiotic administration were not different between PCR-positive and PCR-negative groups (P > 0.05). All patients with Enterovirus had a favorable clinical outcome.A predictive model was created using 3 baseline variables independently associated with a positive Enterovirus PCR (P < 0.05): May to November presentation, CSF protein of less than 100 mg/dL, and absence of focal neurologic signs. The model classified patients into 2 risk categories for a positive Enterovirus PCR (low risk, 0% [0/17 patients]; high risk, 42% [50/120 patients]; P < 0.001).

CONCLUSIONS

Our predictive model can be used to identify children for whom Enterovirus PCR testing is warranted. Such testing could avoid unnecessary hospitalization and antibiotic administration.

Diagnostic accuracy of two multiplex real-time polymerase chain reaction assays for the diagnosis of meningitis in children in a resource-limited setting

INTRODUCTION

Accurate etiological diagnosis of meningitis is important, but difficult in resource-limited settings due to prior administration of antibiotics and lack of viral diagnostics. We aimed to develop and validate 2 real-time multiplex PCR (RT-PCR) assays for the detection of common causes of community-acquired bacterial and viral meningitis in South African children.

METHODS

We developed 2 multiplex RT- PCRs for detection of S. pneumoniae, N. meningitidis, H. influenzae, enteroviruses, mumps virus and herpes simplex virus. We tested residual CSF samples from children presenting to a local paediatric hospital over a one-year period, whose CSF showed an abnormal cell count. Results were compared with routine diagnostic tests and the final discharge diagnosis. We calculated accuracy of the bacterial RT-PCR assay compared to CSF culture and using World Health Organisation definitions of laboratory-confirmed bacterial meningitis.

RESULTS

From 292 samples, bacterial DNA was detected in 12 (4.1%) and viral nucleic acids in 94 (32%). Compared to CSF culture, the sensitivity and specificity of the bacterial RT-PCR was 100% and 97.2% with complete agreement in organism identification. None of the cases positive by viral RT-PCR had a bacterial cause confirmed on CSF culture. Only 9/90 (10%) of patients diagnosed clinically as bacterial meningitis or partially treated bacterial meningitis tested positive with the bacterial RT-PCR.

DISCUSSION

In this population the use of 2 multiplex RT-PCRs targeting 6 common pathogens gave promising results. If introduced into routine diagnostic testing, these multiplex RT-PCR assays would supplement other diagnostic tests, and have the potential to limit unnecessary antibiotic therapy and hospitalisation.

Multicenter Assessment of Gram Stain Error Rates

Gram stains remain the cornerstone of diagnostic testing in the microbiology laboratory for the guidance of empirical treatment prior to availability of culture results. Incorrectly interpreted Gram stains may adversely impact patient care, and yet there are no comprehensive studies that have evaluated the reliability of the technique and there are no established standards for performance. In this study, clinical microbiology laboratories at four major tertiary medical care centers evaluated Gram stain error rates across all nonblood specimen types by using standardized criteria. The study focused on several factors that primarily contribute to errors in the process, including poor specimen quality, smear preparation, and interpretation of the smears. The number of specimens during the evaluation period ranged from 976 to 1,864 specimens per site, and there were a total of 6,115 specimens. Gram stain results were discrepant from culture for 5% of all specimens. Fifty-eight percent of discrepant results were specimens with no organisms reported on Gram stain but significant growth on culture, while 42% of discrepant results had reported organisms on Gram stain that were not recovered in culture. Upon review of available slides, 24% (63/263) of discrepant results were due to reader error, which varied significantly based on site (9% to 45%). The Gram stain error rate also varied between sites, ranging from 0.4% to 2.7%. The data demonstrate a significant variability between laboratories in Gram stain performance and affirm the need for ongoing quality assessment by laboratories. Standardized monitoring of Gram stains is an essential quality control tool for laboratories and is necessary for the establishment of a quality benchmark across laboratories.