Unidentified Streptococci from Plants

Abstract

The unidentified streptococci from plants are catalase negative, gram positive, usually lanceolate cells occurring in pairs and short chains. More than one-half of the 505 strains investigated conform generally to the description of Streptococcus fueciurn, but many deviate in one or more of Sherman's characteristics, growth on bile-esculin agar, and acidification of milk. A few strains superficially resemble Streptococcus luctis. The strains not termed S. fueciurn-like are heterogeneous in adherence to Sherman's characteristics, growth and pigmentation on tellurite and tetrazolium agars, and the heme peroxidase reaction; 35 fermentation patterns were established from the fermentations of arabinose, raffinose, melezitose, melibiose, mannitol, and sorbitol. The diversity in properties indicates that the cultural reactions do not permit definitive characterization or speciation. It is suggested that the S. fueciurn-like strains have provided the ancestral pool from which the species as now described has become adapted to life within the animal host.The unidentified streptococci of plants and vegetables form a heterogeneous group which is second numerically and in frequency of distribution only to Leuconostoc rnesenteroides (20). Some have been described as being Streptococcus fueciurn-like (21, 22) and sharing characteristics with s. fueculis (6). Splittstoesser et al.(29, 30) and White and White (33) isolated atypical streptococci from frozen vegetables.Atypical streptococci bearing the group D antigen have been isolated from feces of pigs (8, 9), feces and tonsils of pigs (13), canned hkLms (2), and humans (18). A characteristic feature of several studies is the highly variant pattern in the fermentations of selected carbohydrates (2, 9), which appears to be shared by members of S. bovis (16,17,25) and S. luctis (31).The streptococci reported in this paper were isolated from plants and vegetables (20). They are usually lanceolate, but sometimes spherical, catalase-negative, homofermentative bacteria occurring in pairs and in short chains. They were studied and are reported as two groups based upon segregation a t the time of isolation. One group is termed S. fueciurn-like, and the second group is other streptococci. MATERIALS AND METHODSMaintenance and propagation of cultures. All cultures have been maintained since isolation in 3% tryptic(ase) soy-l6% glycerol-84% water broth a t -18 C. Upon recall from storage, they were cultivated routinely in the basal medium of Mallmann and Seligmann (15), which was modified to exclude the sodium azide and to include 1 ml of 1.6% alcoholic solution of bromocresol purple (MJ medium) per liter. Inoculations of media were made from young broth cultures upon solid media with loops or needles and into liquid media as single drops from pipettes. Colonial characteristics and pigmentation on 2,3,5-triphenyltetrazolium chloride agar ( 1) were obtained by streaking for isolated colonies. The most reliable reactions on heme peroxidase medium (34) were obtained by making short, heavy st...

Identification of plant-associated enterococci

“…Enterococci of plant origin atypical in physiology have already been reported by Mundt (1975, 1982) before the taxonomical changes in the genus Streptococcus . Of more than 2200 cultures, 26% resembled but were not identical to Streptococcus faecium (now named Ent.…”

“…The so‐called Strep. faecium ‐like strains mostly failed to grow at 45°C, relatively few deaminated arginine and the fermentations of arabinose, raffinose, melezitose, melibiose, mannitol and sorbitol yielded 35 different patterns (Mundt 1975). These phenotypic characteristics seem to be similar to those of the Ent.…”

Population dynamics and antagonistic potential of enterococci colonizing the phyllosphere of grasses

“…In phenotypic features, these strains resembled those which have already been described as Streptococcus faecium (now named Ent. faecium )‐like by Mundt (1975, 1982). However, the 16S rDNA sequence of a representative strain of our isolates revealed the closest relationship to the species Ent.…”

Faecal streptococci as faecal pollution indicators: A review. Part II: Sanitary significance, survival, and use

“…These differences have included biochemical reactions and DNA/DNA homology (Mundt 1975). Geldreich et al (1964) detected starch hydrolysis in 37.7% of enterococci cultures isolated from plants, whereas this characteristic was uncommon in strains recovered from other sources.…”