Haemophilus influenzae Type f Meningitis With an Intraventricular Abscess

Haemophilus influenzae (Hi) is a key pathogen causing bacterial meningitis in children. The introduction of the Haemophilus influenzae type b (Hib) vaccine has significantly reduced the incidence of invasive Haemophilus influenzae disease (IHD). However, cases caused by non-type b strains, such as type f (Haemophilus influenzae type f (Hif)), are gradually increasing, although they remain rare. We report a case of Hif meningitis complicated by an intraventricular abscess in an 11-month-old boy with no significant medical history. He presented with a high fever and lethargy over two days. Cerebrospinal fluid (CSF) analysis revealed pleocytosis and hypoglycorrhachia, while brain magnetic resonance imaging (MRI) identified an intraventricular abscess. Cultures confirmed the presence of Hif with β-lactamase-negative ampicillin resistance (BLNAR). The patient was treated with intravenous dexamethasone, cefotaxime, and meropenem. Due to a drug rash during cefotaxime therapy, meropenem was reinstated. Follow-up imaging showed complete resolution of the abscess, and the patient recovered fully after a 62-day course of treatment without long-term complications. This case highlights the emerging threat of invasive Hif infections, particularly BLNAR strains, which complicate treatment options. The report underscores the importance of ongoing surveillance of Haemophilus influenzae serotypes and resistance patterns to guide effective management and improve outcomes in such rare but severe infections.