Bacterial infection in the lungs followed by sepsis or septicemia is a leading cause of mortality, morbidity, and health care costs. Pulmonary infections are a risk factor for Acute Lung Injury (ALI)/acute respiratory distress syndrome (ARDS). Despite recent advances in management, ARDS outcomes and mortality remain high. This could be due to the fact that the critical mechanisms associated with the pathogenesis of ALI/ARDS remain unresolved. Microbes that cause pneumonia enter the lungs after being inhaled into the airways. Pneumonia occurs in both community and hospital settings that can affect immunocompetent and immunocompromised individuals. In clinical settings, the use of antimicrobial agents works in conjunction with the host immune system to eliminate the pathogen.

The major roadblock to treat bacterial infections is the emergence of drug-resistant strains. Therefore, new treatment strategies are warranted. In this regard, the development of host-targeted therapeutics will be of value. However, understanding the molecular and cellular mechanisms associated with immune responses is critical. Neutrophils are the first responders in response to bacterial infection in the lungs. In addition to phagocytosis and intracellular killing, neutrophils produce NETs to clear extracellular bacteria. In the last decade, the molecular and cellular mechanisms related to the role of NETs in bacterial killing has been delineated in detail.