Author: Glossary

Genus of anaerobic Gram-positive straight or curved rods, non-motile, non-sporing, occurring in long chains or filaments but not showing branching. Present in the intestinal tracts and lesions of warm-blooded animals, especially appendix abscesses.  

Method for the demonstration of Rickettsia and the larger elementary bodies. A buffered and formalized solution of methylene blue (or Azur II) freshly mixed, is supplied and this followed directly by dilute acidified safranin ‘O’. Cells are red, rickettsia or elementary bodies blue.  

Casein hydrolysis is a characterization test of Bacillus species, and shown by an area of clearing around colonies growing on milk agar. The agar is dehydrated nutrient agar made with half normal water content, cooled, and the volume completed with sterile, skimmed milk.  

Substitute for peptone in bacteriological culture media, casein hydrolysate is formed by acid or enzymic digestion of milk, and contains amino acids, salts and growth factors. More regular in composition than peptones, casein hydrolysate is favoured in synthetic media where a high degree of reproducibility is required. A product derived from the milk protein casein…

The ability of Bacillus and some Mycobacteria and Nocardia to digest casein is a secondary characterization test performed by growing the strains on a mixture of equal parts of sterilized skimmed or dialysed milk and double strength nutrient agar. Incubation is up to 2 weeks; hydrolysis is shown by clearing of the opaque medium around…

Broad-spectrum semi-synthetic penicillin, not resistant to acid or penicillinase, less active than benzylpenicillin against Gram-positive bacteria, but unique among penicillins in its inhibition of P%. aeruginosa-, active also against many other Gram-negative bacteria. Administration is parenteral, and the action bactericidal. An antibiotic that is effective against a wide range of bacterial infections. It is poorly…

Test of disinfectant efficiency. Additions of bacterial suspension are made at 3 successive 10-minute intervals, contaminating and diluting the test sample, which is prepared in hard water. Not more than 3 of 5 subcultures made after the last addition should show growth.