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Direct PCR assay for detection of Neisseria meningitidis in human cerebrospinal fluid
1Department of Microbiology, Faculty of Pharmacy, Zagazig University, Egypt.
Abstract:
A PCR amplification was performed to detect Neisseria meningitidis insertion sequence 1106 (IS-1106) in the human CerebroSpinal Fluid (CSF) in cases of meningitis. The study included 27 CSF samples from suspected meningitis patients. Although the inflammatory response in most of the samples was slightly increased, the results showed that 7 (26%) and 8 (30%) CSF samples were diagnosed as meningococcal meningitis by Gram staining and by culture, respectively. The primers of the IS-1106 were used for direct diagnosis of N. meningitidis in the human spinal fluid after a minor treatment of the CSF samples. The sample was diagnosed as meningococcal meningitis, if a DNA band of about 600 bp was detected in the ethidium bromide-stained agarose gel. The 27 CSF samples were analyzed in a random manner. Of these, 18 samples including the Gram staining- and culture-positive samples were also positive in PCR amplification. However, a CSF sample, which was diagnosed to be meningococcal meningitis in culture was negative in both Gram staining and PCR analysis. The specificity of the IS-1106 primers was determined to be 95%, with 100% sensitivity in comparison to Gram staining and culture. The primers were sensitive to 10 pg or more of meningococcal DNA. In addition, the PCR amplification showed high predictive values (89 and 100%) in diagnosing meningitis in patients that were negative and positive responders when tested by culture and by Gram staining. In conclusion, the PCR amplification of IS-1106 of N. meningitidis is specific and sensitive to both culture-positive and -negative meningococcal meningitis. Hence, PCR assay is highly recommended for use in a rapid diagnosis of suspected meningitis patients.
Insights
PCR amplification of Neisseria meningitidis IS-1106 offers a rapid and accurate diagnostic method for meningitis. This sensitive and specific test aids in identifying meningococcal meningitis, even in culture-negative cases.
Area of Science:
- Microbiology
- Molecular Diagnostics
- Infectious Diseases
Background:
- Meningitis diagnosis relies on methods with varying sensitivity and specificity.
- Neisseria meningitidis is a significant cause of bacterial meningitis.
- Rapid and accurate diagnostic tools are crucial for effective meningitis management.
Purpose of the Study:
- To evaluate the efficacy of PCR amplification targeting IS-1106 for detecting Neisseria meningitidis in CerebroSpinal Fluid (CSF).
- To compare PCR-based diagnosis with traditional methods like Gram staining and culture.
- To determine the sensitivity, specificity, and predictive values of the PCR assay.
Main Methods:
- PCR amplification was used to detect the IS-1106 insertion sequence of N. meningitidis in 27 CSF samples.
- CSF samples were analyzed for DNA bands of approximately 600 bp.
- Results were compared with Gram staining and bacterial culture findings.
Main Results:
- PCR detected N. meningitidis in 18 out of 27 CSF samples, including those negative by Gram staining or culture.
- The IS-1106 PCR assay demonstrated 95% specificity and 100% sensitivity compared to Gram staining and culture.
- High predictive values (89-100%) were observed for the PCR assay.
Conclusions:
- PCR amplification of IS-1106 is a highly specific and sensitive method for diagnosing meningococcal meningitis.
- The PCR assay is effective in identifying both culture-positive and culture-negative cases.
- This PCR approach is recommended for rapid diagnosis in suspected meningitis patients.