A. Carlotti et G. Funke, RAPID DISTINCTION OF BREVIBACTERIUM SPECIES BY RESTRICTION ANALYSIS OF RDNA GENERATED BY POLYMERASE CHAIN-REACTION, Systematic and applied microbiology, 17(3), 1994, pp. 380-386
Twelve reference strains, including the type strains, of species eithe
r belonging or related to the genus Brevibacterium, and nineteen well-
characterized clinical isolates assigned to this genus were studied. P
olymerase chain reaction was used for partial amplification of the gen
e coding for their 16S rRNA (rDNA genes) which were digested with nine
different restriction endonucleases. The amplified rDNAs were approxi
mately 1300 bp long. The type strains of B. casei and B. epidermidis e
xhibited different BstNI rDNA restriction patterns. Furthermore, these
patterns differed from those observed for B. linens and B. iodinum. O
f the clinical isolates fifteen had the same BstNI restriction pattern
as the B. casei type strain, two the same as the B. epidermidis type
strain, one the same as B. linens, and one strain had a particular pat
tern. Results obtained by rDNA restriction analysis were confirmed by
DNA-DNA hybridization studies, which revealed that representatives of
the fifteen isolates resembling B. casei shared more than 75% homology
with B. casei CIP102111(T). Combined with a rapid DNA extraction proc
edure, PCR-amplified-rDNA restriction fragment analysis allowed the di
stinction of the different Brevibacterium species in less than seven h
ours. The results suggested that most brevibacteria from clinical samp
les belongs to B. casei rather than B. epidermidis, as commonly though
t. This approach may also be of value for differentiation within other
genera of Gram-positive bacteria.