Cross reactivity of Neisseria meningitidis crgA diagnostic PCR primers with nontypeable haemophilus influenzae.

BACKGROUND: CrgA based PCR are usually used for diagnosis of Neisseria meningitidis while the crgA gene was observed in the genomes of Haemophilus influenzae. In this study, we aimed to evaluate whether the crgA primers routinely used in the diagnosis of N. meningitidis could cross react with H. influenzae isolates. METHODS: A diagnostic test study analysis of sixty-two H. influenzae isolates from oropharyngeal swabs of healthy individuals aged 9 to 11 years between 2011 and 2012, using commonly used crgA primers for diagnostic analysis of N. meningitidis. RESULTS: It revealed that 19.3% nontypable H. influenzae isolates were positive for the crgA gene. All the biotype IV H. influenzae isolates were crgA PCR positive. CONCLUSIONS: Our study has shown a significant finding of crgA gene especially in bitotype IV nontypable H. influenzae by N. meningitidis crgA diagnostic PCR primers. It is necessary to further evaluate the prevalence of the crgA gene in more non-typable H. influenzae strains, particularly invasive strains.