Haemophilus are a group of bacteria that do not have a cell wall. They include both strains that are harmless to human and those that cause serious diseases such as sepsis, meningitis and chancroid. Haemophilus is often difficult to detect because they do not grow in a standard blood culture. However, it will grow in a culture that contains chocolate and if on the same blood culture plate as staphylococcus as the staph bacteria will release factors necessary for haemophilus growth as part of their own metabolism.