Genus of gram‐negative, nonmotile, microaerophilic, pleomorphic bacilli and coccobacilli.
A genus of acteria which needs specific factors in the blood to grow.
Genus within the bacteriological family of the Brucellaceae, consisting of small aerobic non-motile and non-sporing Gram-negative bacilli, most frequently of respiratory tract origin. Growth requires accessory factors contained in blood, and known as X factor (haematin) and V factor (a co-enzyme, acting as a hydrogen acceptor in the oxidation-reduction processes of the organism). Cultivation is therefore performed on fresh blood agar or chocolate agar, resulting in small iridescent colonies, films of which show fine Gram-negative rods, frequently very pleomorphic. Levinthal’s medium has also been advocated.
Gram-negative, rod-like bacteria. Often found in the respiratory tract, they may be harmless but can be responsible for several diseases. The main pathogenic species of haemophilus is H. influenzae, which may cause severe exacerbations of chronic bronchitis, as well as meningitis, epiglottitis, sinusitis, and otitis media. Other species may cause conjunctivitis or chancroid. Haemophilus species are sensitive to a wide range of antibiotics, though generally resistant to penicillin. Infants are routinely immunized with Haemophilus B vaccine to prevent meningitis, septicaemia and epiglottitis all potentially fatal disesases which have almost disappeared in the UK, with the only sufferers being those who are unimmunized or infected with the rarer non type-B organisms.
The formation of blood cells and platelets a continuous process throughout life. As ageing cells are removed from the circulation, new ones, generated in the bone marrow, replace them.
A genus of gram-negative, nonmotile bacilli; some are normal flora of the upper respiratory tract, and others cause serious illness.