Development and evaluation of a selective and differential medium for the primary isolation ofPeptostreptococcus micros

Abstract

Peptostreptococcus micros, an anaerobic gram-positive coccus, has been associated with periodontal and endodontic lesions, including those refractory to treatment, as well as many human polymicrobial infections in other body locations. A selective and differential medium for the primary isolation of P. micros was developed and evaluated. Columbia CNA agar, a selective medium for gram-positive cocci, was supplemented with glutathione and lead acetate (P. micros medium: PMM). P. micros has a characteristic of rapidly utilizing the reduced form of glutathione to form hydrogen sulfide, which reacts with lead acetate producing a black precipitate in the medium. When grown on PMM, P. micros can be easily identified by its typical colonial morphology and the presence of a black precipitate directly under the colony. PMM was compared for the growth of P. micros with phenylethyl alcohol agar (PEA) and Columbia base medium (CBM) with 80 strains of P. micros and 30 strains of other gram-positive cocci. All P. micros isolates tested grew and showed the typical morphology of P. micros on PMM. Using colony counts on CBM as controls, there was an average 81.8% recovery in the number of P. micros colonies on PMM, in contrast to an average 6.1% recovery on PEA. Subgingival plaque and tongue samples from 12 adult periodontitis and 6 early-onset periodontitis patients were cultured onto PMM for the isolation of P. micros. P. micros was isolated on PMM and identified biochemically and enzymatically from both adult periodontitis and early-onset periodontitis patients with higher percentages isolated from the diseased periodontal pockets of adult periodontitis patients; furthermore, this is the first isolation of P. micros from tongue samples taken from periodontally diseased patients. This medium in cultural studies will further our understanding and assist future investigations of P. micros involved in disease processes.

Detection of Peptostreptococcus micros DNA in clinical samples by PCR

“…P. micros is commonly identi®ed on the basis of colony morphology, oxygen tolerance and Gram's staining characteristics, followed by analysis of its enzymic activities (API ZYM, Rapid ID 32A) and its capacity to hydrolyse amino acid and phosphate substrates (RapID ANA II) [5,18]. A selective and differential medium has been described that facilitates the primary isolation of P. micros from clinical samples which is based upon a Columbia CNA agar, supplemented with glutathione and lead acetate [15], that is selective for gram-positive cocci. When grown on this medium, P. micros utilises the reduced form of glutathione to form H 2 S, which reacts with lead acetate to produce a black precipitate that is clearly visible below P. micros colonies.…”

“…A selective and differential medium for the primary isolation of P. micros has been described [15]. Monoclonal antibodies (MAbs) recognising speci®c surface antigens of P. micros have been generated and successfully applied to its detection in clinical samples in an indirect immuno¯uorescence assay [16].…”

A review of the current literature on aetiology and measurement methods of halitosis

“…36 Bacteria known to produce volatile sulphur-containing compounds include Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans), Actinomyces species, Atopobium parvulum, Campylobacter rectus, Desulfovibrio species, Eikenella corrodens, Eubacterium sulci, Fusobacterium species, Peptostreptococcus micros, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella species, Solobacterium moorei, Tannerella forsythia (formerly Bacteriodes forsythus or Tannerella forsythensis), Treponema denticola, Veillonella species, Vibrio species, a phylotype of Dialister, a phylotype of the uncultivated phylum, and a phylotype of Streptococcus, and as yet unidentified sulphur-reducing bacteria. 22,[33][34][35][37][38][39][40][41][42][43][44][45][46] The species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. Also, the role of uncultivable bacteria may be important in contributing to this complex process.…”

In vivo antimicrobial effectiveness of an essential oil‐containing mouth rinse 12 h after a single use and 14 days' use

“…The following media were used: Schaedlers medium (STA) to enumerate total anaerobic bacteria; Schaedlers Nalidixic/Vancomycin medium (SNV) to enumerate total Gram-negative anaerobes; and OOPS medium supplemented with 5% sheep's red blood cells (El-Halabi et al 1999) to enumerate VSC-producing organisms (Turng et al 1996). Dilutions of 10 À 2 and 10 À 4 were plated in duplicate on selective media using a spiral plater.…”