A RAPD-based comparison of thermophilic bacilli from milk powders.
The similarity of strains of thermophilic Geobacillus stearothermophilus (formerly Bacillus stearothermophilus), Anoxybacillus flavithermus (formerly Bacillus flavothermus), Bacillus licheniformis and Bacillus subtilis isolated from separate milk powder production runs from multiple factories was examined using a random amplified polymorphic DNA (RAPD) protocol. As a result of the analysis of the RAPD fingerprints and data relating to general growth and biochemical tests, over 98% of the 1470 isolates examined (grown at 55 degrees C) were assigned to the species G. stearothermophilus, A. flavithermus, B. licheniformis and B. subtilis. The G. stearothermophilus isolates were identified as being nearly identical to G. stearothermophilus (DSMZ 22; equivalent to ATCC 12980), or G. stearothermophilus var. calidolactis (DSMZ 1550). Three groups of isolates were found to be related to A. flavithermus (DSMZ 2641) by partial small ribosomal subunit (16S) sequence comparisons and shown to be interrelated by RAPD analyses with multiple primer sets. The thermophilic isolates of B. licheniformis were positively identified by comparison with type strains of B. licheniformis DSMZ 13 and DSMZ 8785. All of the B. subtilis strains shared bands in their RAPD profiles and were similar to a common B. subtilis type strain (DSMZ 10 and DSMZ 347). Overall, the most common and prevalent group of strains (group A) was demonstrated to be closely related to G. stearothermophilus (DSMZ 22).
Ronimus
Ron S
RS
Thermophile Research Unit, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, New Zealand. ronimus@waikato.ac.nz
Parker
Lynne E
LE
Turner
Nicola
N
Poudel
Sushma
S
Rückert
Andreas
A
Morgan
Hugh W
HW
D000818:Animals; D001407:Bacillus / Q000145:classification* / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005516:Food Microbiology; D008892:Milk / Q000382:microbiology*; D008969:Molecular Sequence Data; D019105:Random Amplified Polymorphic DNA Technique; D012689:Sequence Homology, Nucleic Acid
D004269:DNA, Bacterial; D004275:DNA, Ribosomal