Moraxella is a genus of bacteria that are typically found in the human respiratory tract. They are gram-negative, rod-shaped organisms that can be part of the normal flora but may also cause infections, particularly in individuals with weakened immune systems or underlying health conditions. One of the most well-known species is Moraxella catarrhalis, which is associated with respiratory infections such as sinusitis and bronchitis. This bacterium can also lead to ear infections in children and is known for its ability to resist certain antibiotics, making treatment more challenging.