Identification of Common Bacterial Pathogens Causing Meningitis in Culture-Negative Cerebrospinal Fluid Samples Using Real-Time Polymerase Chain Reaction

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

MicroRNA-146a expression as a potential biomarker for rheumatoid arthritis in Egypt

AbstractBackgroundMicroRNAs (miRNAs) are small non-coding RNAs, whose role in regulating diverse immune functions, suggests they might play a role as biomarkers for immune mediated disorders. Studies showed that miRNA-146a (miR-146a) expression is increased by proinflammatory cytokines and is an important modulator of differentiation and function of cells of innate and adaptive immunity.Aim of the workThe current study aimed to evaluate the expression of miR-146a as a potential biomarker for diagnosis of rheumatoid arthritis (RA) and to explore its association with disease activity.Subjects and methodsThe study enrolled 50 Egyptian subjects divided into a patient group, which comprised 25 RA patients, and a control group which comprised 25 healthy individuals. The disease activity for the patients’ group was determined by simplified disease activity index. Relative quantification of miR-146a expression in whole blood was determined using reverse transcriptase quantitative real time polymerase chain reaction.ResultsThere were highly significant statistical differences between patients and healthy controls as regards miR-146a relative expression, erythrocyte sedimentation rate (ESR) and anti-cyclic citrullinated peptide (anti-CCP) (p<0.001). Highly significant statistical differences (p<0.001) were also found between different patients’ subgroups as regards miR-146a relative expression and ESR. miR-146a levels correlated positively with those of ESR, C-reactive protein and anti-CCP (p<0.001).miR-146a illustrated best performance in diagnosing RA, showing the highest sensitivity and specificity (96% and 100%, respectively) (AUC: 0.992 at a cut off value of ⩾2.16) compared to anti-CCP (sensitivity: 68%, specificity: 100% and AUC: 0.87 at a cut off value of ⩾22U/ml) and RF (sensitivity: 56%, specificity: 80% and AUC: 0.992 at a cut off value of ⩾13U/ml).ConclusionThis study demonstrated that miR-146a expression was highly significantly elevated in whole blood of patients with RA. Its diagnostic performance was better than anti-CCP and RF and its level of expression correlates with disease activity