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Identification of Common Bacterial Pathogens Causing Meningitis in Culture-Negative Cerebrospinal Fluid Samples Using
Walaa Shawky Khater1, Safia Hamed Elabd1
1Medical Microbiology and Immunology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt.
Abstract:
Background. Meningitis is a serious communicable disease with high morbidity and mortality rates. It is an endemic disease in Egypt caused mainly by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. In some settings, bacterial meningitis is documented depending mainly on positive cerebrospinal fluid (CSF) culture results or CSF positive latex agglutination test, missing the important role of prior antimicrobial intake which can yield negative culture and latex agglutination test results. This study aimed to utilize molecular technology in order to diagnose bacterial meningitis in culture-negative CSF samples. Materials and Methods. Forty culture-negative CSF samples from suspected cases of bacterial meningitis were examined by real-time polymerase chain reaction (real-time PCR) for the presence of lytA, bexA, and ctrA genes specific for Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, respectively. Results. Positive real-time PCR results for Streptococcus pneumoniae were detected in 36 (90%) of culture-negative CSF samples while no positive results for Haemophilus influenzae or Neisseria meningitidis were detected. Four (10%) samples were negative by real-time PCR for all tested organisms. Conclusion. The use of molecular techniques as real-time PCR can provide a valuable addition to the proportion of diagnosed cases of bacterial meningitis especially in settings with high rates of culture-negative results.
Insights
Real-time PCR successfully diagnosed bacterial meningitis in 90% of culture-negative cerebrospinal fluid (CSF) samples, primarily identifying Streptococcus pneumoniae. This molecular technique significantly improves bacterial meningitis diagnosis, especially when traditional methods fail due to prior antibiotic use.
Area of Science:
- Infectious Diseases
- Microbiology
- Molecular Diagnostics
Background:
- Bacterial meningitis presents significant morbidity and mortality, endemic in Egypt.
- Common causative agents include Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae.
- Traditional diagnostics (CSF culture, latex agglutination) can be negative due to prior antimicrobial use.
Purpose of the Study:
- To employ molecular technology for diagnosing bacterial meningitis in culture-negative CSF samples.
- To assess the utility of real-time PCR in identifying key bacterial meningitis pathogens.
Main Methods:
- Real-time polymerase chain reaction (PCR) was used to analyze 40 culture-negative CSF samples.
- Specific genes (lytA, bexA, ctrA) for S. pneumoniae, H. influenzae, and N. meningitidis were targeted.
- Samples were from patients suspected of having bacterial meningitis.
Main Results:
- Real-time PCR detected Streptococcus pneumoniae in 36 (90%) of the culture-negative CSF samples.
- No Haemophilus influenzae or Neisseria meningitidis DNA was detected.
- Four (10%) samples tested negative for all targeted organisms via real-time PCR.
Conclusions:
- Real-time PCR is a valuable tool for diagnosing bacterial meningitis, particularly in cases with negative culture results.
- Molecular diagnostics enhance the detection rate of bacterial meningitis, overcoming limitations of conventional methods.
- This approach is crucial in settings where prior antibiotic administration is common.
