Carbon Source Utilization Tests Research Articles

Taxonomie de Bacillus circulans

Four strains of Bacillus circulans sensu stricto (ATCC 4513 (typestrain), 4515, 4516, and 4530) were subjected to 236 morphological, biochemical and physiological tests, including 162 carbon source utilization tests. B. circulans s. s. is a species of facultative anaerobes able to ferment carbohydrates. Many carbohydrates and a few aliphatic acids were used as sole carbon and energy sources, but amino acids were not. The guanine-plus-cytosine content of DNA (four strains studied) was 37.2±0.4 mol % (mean±standard deviation).

Species and biotype identification ofSerratia strains associated with insects

Forty-eightSerratia strains associated with insects were, identified to species level and biotyped according to recent taxonomic schemes. Each strain was submitted to 36 biochemical tests, including 23 carbon source utilization tests. Twenty-eight strains were assigned to eight biotypes ofSerratia marcescens: A1a, A2a, and A6a (pigmented biotypes: 18 strains); and A3a, A3b, A4a, A5, and TCT (nonpigmented biotypes: 10 strains). However, biotypes A8a, A8b, and A8c, which are frequently involved in nosocomial infections, were not found in insects. Ninetten strains were identified asS. liquefaciens (S. proteamaculans) biotypes C1a (12 strains), C1c (4 strains), C1d (2 strains), and one atypicalS. liquefaciens strain. Only one strain was identified asS. marinorubra (a nonchitinolytic species). The recent emergence ofSerratia in human pathology calls for a reevaluation of the idea of usingSerratia to biologically control insects.

Taxonomy of the Genus Serratia

One hundred and fifty-six strains of Serratia and related bacteria including representatives of Enterobacter liquefaciens, Enterobacter cloacae, Enterobacter aerogenes, Erwinia carotovora, Erwinia chrysanthemi, Erwinia herbicola and Erwinia nimipressuralis were studied using 223 morphological, physiological, biochemical and carbon source utilization tests. The results were subjected to computer analysis. At the 80% similarity level all strains, except two, grouped into eight phenons representing: (A) Serratia marcescens with the neotype CCM303 (ATCCI3880); (B) S. marinorubra with the monotype NCTC10912 (ATCC27614); (CI) S. liquefaciens with the type ATCCI4460; (C2) S. plymuthica with the monotype CCM640 (ATCC183); (D) Erwinia herbicola with the neotype of Enterobacter agglomerans NCTC9381; (E) Enterobacter cloacae with the neotype NCTCI0005 and Erwinia nimipressuralis; (F) Erwinia carotovora with the type ATCC495, Erwinia atroseptica and Erwinia chrysanthemi; (G) Klebsiella mobilis with the neotype NCTCI0006. At the 70% similarity level the phenons formed two groups: (A, B, CI, C2) and (D, E, F, G). The following conclusions were drawn. (I) There are three species of enterobacteria producing prodigiosin: S. marcescens, S. plymuthica and S. marinorubra. (2) There are four species of Serratia, one colourless (S. liquefaciens). (3) Subphenons (biovars) are described within the four species of Serratia. (4) Non-pigmented wild-type strains of S. marcescens can generally be differentiated from pigmented strains by characters other than pigmentation, because subphenons are homogeneous with respect to pigmentation. This survey raised some problems of nomenclature because old descriptions could be found that could loosely fit the present phenons. Comparison with an authentic culture was considered to be the most objective way of identifying these phenons with earlier named species.

Carbon source utilization tests as an aid to the classification of non-fermenting gram-negative bacteria.

SUMMARY: Some factors which affect the results of carbon source utilization (CSU) tests were investigated with 187 strains of Gram-negative bacteria, chiefly non-fermentative. There was little difference between the results at 37 and 30°C. Repetition of tests showed that 5% of the results were non-reproducible. The variability was most pronounced with acetate, maleate and sucrose amongst the substrates and Loefflerella mallei amongst the bacteria. Prior induction of the bacterial enzymes before testing did not reduce variability nor show any other advantage. Analysis of the results by numerical taxonomic methods revealed differences in the groups of bacteria derived from the results of CSU tests compared with those derived from conventional biochemical test results. CSU tests readily provide a large number of taxonomic features with the advantage of a simple standardized testing procedure.