Typing methods of haemophilus influenzae and it's importance

Haemophilus influenzae is a gram-negative, cocobacilli or bacillus bacterium that can cause systemic and invasive infections. Serotyping of H.influenzae can be done conventionally by capsule-specific antisera or by polymerase chain reaction (PCR) via screening of genes encoding capsuleexpression. Studies have shown that conventional serotyping is less sensitive than molecular methods and cannot accurately identify non-typable H.influenzae (NTHi). In Turkey, the incidence of common serotypes and biotypes in H.influenzae infections has changed after the Hib vaccine, which has been included in the vaccine schedule in 2007, and invasive infections caused by NTHi have started to be defined. Isolated H. influenzae should be typed rapidly and accurately. In addition, β-lactamase activity and ampicillin resistance of this bacterium vary depending on serotype and biotype. Within the scope of our study, serotype and biotype distributions, antibiotic susceptibility and β-lactamase activities of H.influenzae strains isolated from clinical samples from Hacettepe University Hospitals Central Laboratories were investigated. In the light of the data obtained, the rate of serotyped H.influenzae and NTHi, biotyping and antibiotic susceptibilities of the strains isolated in our hospital were determined. In our study, NTHi (78.9%) was the most common serotype by conventional method, followed by Hi f (7.9%) and Hi e (5.6%). In molecular serotyping by NTHi (%66.9) was followed by Hi e (%15.1) and Hi b (6.8%). The correlation between the tests in serotyping was found to be 74.5%. The incidence of biotype III was the highest. Ampicillin resistance was found to be 25% and 44% of these isolates were BLNAR. In conclusion, it was observed that NTHi's were increased in H. influenzae-related infections in adult patients, and the agreement rate between the conventional and molecular serotyping methods was moderate.