Category: S

The spreading of some Proteus species on solid culture media, a feature possibly of the extreme motility of the organism. A variety of methods (none wholly satisfactory) have been devised to prevent the phenomenon, including : (1) high (4 -6 per cent) agar content; (2) electrolyte-free agar; (3) treatment of the inoculum with ether; (4)…

Small, motile cells released from a mother cell, one of the more recently observed mechanisms of bacterial reproduction.  

Organisms the energy of which is derived from the reduction of sulphur or oxidation of thiosulphates, the metabolic end- products corroding metal objects in the soil or water in which they are found.  

Synthesized chemotherapeutic substances derived from sulphanilamide (p-aminobenzenesulphonamide) available in a number of forms for parenteral or (commonly) oral dosage. Sulphonamides are bacteriostatically active against a wide variety of Gram-negative and positive bacteria. Many versions of the drug (usually distinguished by the prefix ‘sulpha-’) have been formulated, varying either in their speed of absorption and/or the…

Culture media to which are added single carbohydrates, alcohols etc., the bacteriological fermentation of which yields acid and possibly gas, providing thereby a key to the identity of the inoculated culture. The media therefore include a nutrient base, the fermentable substance, an indicator of acidity and, when appropriate, an inverted tube (Durham’s tube) for the…

Family within the order Actinomycetales, and consisting of branching filaments growing as a mycelium, with conidia borne on aerial hyphae in chains.  

Lancefield Group C type infecting animals other than bovines.  

α-haemolytic streptococcus, frequently commensal in man, but associated with infections, especially endocarditis. A collection of α-hemolytic streptococci that lack specific group antigens and are typically present in the natural microorganisms of the respiratory tract. These streptococci are responsible for causing dental cavities and bacterial endocarditis.  

β-haemolytic streptococcus of Lancefield’s Group A, associated with scarlet fever, puerperal sepsis, and other forms of human infection. The species is provisionally differentiated from other haemolytic streptococci by its sensitivity to bacitracin. Exotoxins include two haemolysins-O-streptolysin (oxygen-labile) and S-streptolysin (not oxygen sensitive)—and erythrogenic toxin. Strains may also show leucocidin, fibrinolysin, and hyaluronidase. Any of the…

Species associated with pneumonia and other pyogenic infections, Streptococcus pneumoniae appears in fresh material as a pair of oval cocci with their long axes in line; capsules are present. On culture, chains of more rounded cocci may grow, and cap-sularity is often lost. Serum or blood is an aid to isolation, and on blood agar…