Bordetella holmesii is a Gram-negative, rod-shaped bacterium of the genus Bordetella. It was named in recognition of Barry Holmes, a biologist. It is asaccharolytic, oxidase-negative, and nonmotile, producing a brown pigment. It is associated with septicemia, endocarditis, and respiratory illness, especially in immunocompromised patients, such as asplenic or AIDS patients.It is often seen in conjunction with Bordetella pertussis infections (whooping cough), although not always.