With the widespread use of antibiotics active against Bacteroides, especially in abdominal surgical prophylaxis, there has been a decline of detectable anaerobic septicaemias in many British hospitals during the last 15 years.Īnaerobic streptococci may occasionally invade the blood from an infected female genital tract or from oral sepsis.Ĭlostridial septicaemia due mainly to Clostridium perfringens is rare today in Britain. coli or other coliforms in the blood ( see Chapter 9). Abdominal or gynaecological sepsis, is usually present and Bacteroides may be mixed with E. These species can clinically cause a septicaemia that is indistinguishable from that produced by aerobic causes of Gram-negative septicaemia. Shanson MB, FRCPath, in Microbiology in Clinical Practice (Second Edition), 1989 Anaerobic Septicaemiaīacteroides fragilis and other Bacteroides species are the main causes of anaerobic septicaemia. gingivalis have been reclassified with the new genus name Porphyromonas.ĭ.C. The oralis-melaninogenicus group has been assigned to the genus Prevotella, and includes the former B. fragilis group will include the other bile-tolerant anaerobes such as B. It has been proposed that these groups be designated as new genera. Three main groups were distinguished: the ‘fragilis group’ which contained the bile-tolerant organisms, the ‘oralis-melaninogenicus’ group which contained non-bile tolerant saccharolytic organisms, and the asaccharolytic group. The genus Bacteroides, as previously constituted, included a very diverse range of organisms with a DNA base composition varying between 28 and 61 mol per cent. These organisms form the major part of the bacterial flora of the gut, mouth, and female genital tract and form an important part of the non-specific defence against infection with pathogens. The main Gram-negative anaerobic organisms isolated from human sources are found in the Bacteroides, Prevotella, Porphyromonas (see below), Fusobacterium and Leptotrichia species. The genera Bacteroides and Fusobacterium are phylogenetically related to the Flavobacterium and Cytophaga genera. The Bacteroidaceae include anaerobic Gram-negative species found in many human infections. Gillespie MB, BCh, BAO, MRCP(UK), MRCPath, in Medical Microbiology Illustrated, 1994 Introduction