Abstract
Haemophilus influenzae is an aerobic gram-negative bacillus that can colonize the upper respiratory tract in humans. However, it is rarely recognized as a cause of invasive infections in adults. We analyzed invasive H. influenzae infections in patients hospitalized at the Cardinal Stefan Wyszyński Regional Specialist Hospital in Lublin (WSS) from January 1, 2022, to May 31, 2024. We observed a significantly higher number of invasive infections caused by this pathogen compared to the previous months analyzed (3 cases per month vs. 0.095 cases per month; p<0.05). Failure of empirical antibiotic therapy is often due to multidrug resistance of detected strains. The increasing trend of invasive H. influenzae infections is also reported by the National Reference Center for Bacterial Infections of the Central Nervous System.