Author: Glossary

The genus of spirochaetes which (compared with the treponema and leptospira) are larger (up to 30μm), more refractile, stain by conventional methods, and possess open coils of large wave-length. Both commensal and pathogenic species occur, and some are cultivable on special media. Borrelia, a group of bacteria characterized by their spiral shape, are transmitted through…

Nutrient digest or infusion agar plus 5-10 per cent blood (of horse usually), oxalated or defibrinated, added at 55 C. Employed nutritionally for the cultivation of fastidious microbes, but also as an indicator of haemolysis caused by colonial growth products. Chocolate agar is formed by heating set blood agar plates at 60° C for an…

Bacterial staining phenomenon in which the ends of the cell are more deeply coloured than is the central portion.  

Means of differentiating Str. pneumoniae from Str. viridans, a broth culture of the former being soluble in bile (10 per cent sodium taurocholate). A variation of the test uses sodium desoxycholate solution instead of bile. The tests have been largely superseded by the optochin test.  

A constituent of normal mammalian serum possessing bactericid.al qualities against some Gram-positive organisms.  

A surface antigen of the enterobacteriaceae which may mask the ‘0’ antigens of the bacterium on which they are situated.  

Bacteriological filters (candles) prepared from kieselguhr, a fossil diatomaceous earth. The pore size is relatively large, and three sizes are graded V, N and W (viel, normal, wenig)—coarse, normal and fine respectively—that is, in decending porosity. Serratia marcescens should be retained by even the V filter. The filters are moulded in the shape of a…

Irregular staining of bacteria (such as Myco. tuberculosis) giving alternate light and dark areas. Alternating stretches of dilation and stenosis within an artery, usually only seen during angiography.  

Organism of doubtful taxonomy (sometimes classified as Fusobacterium) causing necrosis in animals and occasionally in man. Long (40 -100 μm) Gram-negative filaments, strictly anaerobic.  

The organism associated with Borrelia vincentii in Vincent’s angina. Strictly anaerobic and difficult to cultivate. Also described as Fusobacterium fusiforme.