Volume 3 Issue 2 | 2026 | View PDF
Paper Id:IJMSM-V3I2P110
doi: 10.71141/30485037/V3I2P110

Rapid Detection of Bacteria in Cerebrospinal Fluid: A Comparison Between Fluorescent Microscopy and Conventional Gram Stain

Dr. Charu Jain, Deeksha Srivastava

Citation:
Dr. Charu Jain, Deeksha Srivastava, "Rapid Detection of Bacteria in Cerebrospinal Fluid: A Comparison Between Fluorescent Microscopy and Conventional Gram Stain" International Journal of Multidisciplinary on Science and Management, Vol. 3, No. 2, pp. 89-93, 2026.

Abstract:
Background: Rapid diagnosis of bacterial meningitis is critical to reduce morbidity and mortality. However, the sensitivity of Gram staining is low, particularly in low inoculum and partially treated cases. Acridine Orange (AO) fluorescent microscopy has been suggested as a more sensitive alternative. Objectives: To evaluate the accuracy of Acridine Orange fluorescent microscopy versus Gram stain light microscopy for the diagnosis of bacterial pathogens in Cerebrospinal fluid (CSF). Methods: This prospective comparative study was conducted in the Department of Microbiology, UCMS and GTBH, Delhi, from November 2025 to February 2026. A total of 100 CSF samples from suspected bacterial meningitis cases were analyzed using Gram staining, Acridine Orange staining, and culture (gold standard). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were determined. McNemar’s test and Cohen’s kappa were applied. Results: Of 100 samples, 30 were culture-positive. Acridine Orange demonstrated higher sensitivity (43.3%) compared to Gram stain (23.3%); however, the difference was not statistically significant (p = 0.10), indicating comparable performance in this sample size. Gram stain showed higher specificity (82.9%) than AO (77.1%). The agreement with culture was poor for Gram stain (κ = 0.069) and fair for AO (κ = 0.207), which indicates poor agreement of both tests with the gold standard. Conclusion: Acridine Orange staining shows improved sensitivity but limited agreement with culture. While it may serve as a useful screening tool, Gram staining remains essential for specificity and morphological identification. A combined diagnostic approach is recommended.

Keywords: Acridine Orange, Gram Stain, CSF, Meningitis, Fluorescent Microscopy.

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