Haemophilus influenzae are pleomorphic, oxidase positive, gram-negative coccobacilli rods that commonly colonize and infect the human respiratory tract. 

-H. influenzae are found on the mucous membranes of the upper respiratory tract in humans with the nasopharynx as the most common site of long-term colonization 

-Clinically, H. influenzae is similar to S. pneumoniae, with a slower onset.

-it is spread by airborne droplets or by direct contact with secretions or fomites. 

-its most serious manifestation is meningitis 

-the most prominent strain is Type b 

-risk factors include alcoholism, smoking, chronic lung disease, advanced age, and HIV infection 

Symptoms & Signs 

H influenzae may cause sinusitis, otitis, bronchitis, epiglottitis, pneumonia,pericarditis, cellulitis, arthritis, meningitis, and endocarditis. 

Diagnosis 

Diagnosis can be established by showing gram-negative coccobacilli in culture

Treatment 

Antibiotics: Beta-lactams (amoxicillin, amoxicillin-clavulanate), cephalosporins, fluoroquinolones, macrolides, and tetracyclines

-In Hib meningitis, administration of glucocorticoids reduces the incidence of neurologic sequelae 

Prevention

All children should be immunized with an Hib conjugate vaccine with the primary series at 2–6 months of age, and a booster dose at 12–15 months of age.