IDENTIFICATION AND TYPING OF Haemophilus influenzae IN IRAQI CHILDREN DIAGNOSED WITH MENINGITIS

Abstract

Meningitis is the major cause of morbidity and mortality among infants and children below the age of five years. Meningitis might be caused by infection with viruses, bacteria, fungi or parasites. Haemophilus influenzae represents one of the causing agents of meningitis in children. During 2010, 400 Cerebrospinal fluid (CSF) specimens were collected from children less than 5 years, which clinically diagnosed with meningitis, in several hospitals of Iraq. Microbiological, biochemical and PCR techniques were used for identification and typing of Haemophilus influenzae isolates. Culturing CSF specimens revealed that 11(2.75%) isolates belonging to genus Haemophilus then these isolates were more identified as H. influenzae according to the biochemical properties. According to the biotyping assay, it was found that 55% of H. influenzae isolates were identified as biotype I, 18.2% biotyped as V and VII for each one, and 9% biotyped as II, whereas all isolates (100%) identified as serotype b using slide agglutination test. PCR analysis was used for detection of H. influenzae in 75 specimens of cultured and noncultured CSF which divided into four groups (confirmed, probable, suspected, and control) according to the clinical and laboratory criteria of meningitis. Three genes, ompP6, bexA, and bcs3, were selected to verify the existence of H. influenzae type b using triplex PCR. It was found that 23(30.7%) of 24 H. influenzae were belonged to H. influenzae type b; 11(14.7%) were culture positive -PCR positive while 12 (16%) were culture negative -PCR positive, and only 1(1.3%) had noncapsulated properties for H. influenzae. Moreover, 5(6%) of 23 H. influenzae type b were detected as capsule deficient mutants which had ability to cause meningitis. Furthermore, according to capsular genotypes, hcsA, was indicated that H. influenzae type b was distributed in two types, I and II, type I was predominant (78.3%) in children under 5 years old whereas type II infected only 5(21.7%) children less than 1year old. In conclusions, according to this study H. influenzae serotype b and biotype I was the most common types among children less than 5 years old diagnosed as meningitis in Iraqi children. H. influenzae can be identified directly from CSF by using different types of PCR techniques based on the amplification of cap genes which showed high sensitivity and specificity comparing with culture method.