In vitrobiofilm model for studying tongue flora and malodour

Abstract

Aims: To develop a perfusion biofilm system to model tongue biofilm microflora and their physiological response to sulfur‐containing substrates (S‐substrates) in terms of volatile sulfide compound (VSC) production. Methods and Results: Tongue‐scrape inocula were used to establish in vitro perfusion biofilms which were examined in terms of ecological composition using culture‐dependent and independent (PCR‐DGGE) approaches. VSC‐specific activity of cells was measured by a cell suspension assay, using a portable industrial sulfide monitor which was also used to monitor VSC production from biofilms in situ. Quasi steady states were achieved by 48 h and continued to 96 h. The mean (±SEM) growth rate for 72‐h biofilms (n = 4) was μ = 0·014 h−1 (±0·005 h−1). Comparison of biofilms, perfusate and original inoculum showed their ecological composition to be similar (Pearson coefficient > 0·64). Perfusate and biofilm cells derived from the same condition (co‐sampled) were equivalent with regard to VSC‐specific activities which were up‐regulated in the presence of S‐substrates. Conclusions: The model maintained a stable tongue microcosm suitable for studying VSC production; biofilm growth in the presence of S‐substrates up‐regulated VSC activity. Significance and Impact of the Study: The method is apt for studying ecological and physiological aspects of oral biofilms and could be useful for screening inhibitory agents.

Review:In vitrobiofilm models for studying oral malodour

“…The perfusion biofilm system (see Figure ) incorporating a tongue‐derived microflora (i.e. microcosm in the form of biofilm cells) has been used to study the collective biofilm physiological response to sulfur‐containing substrates (S‐substrates) in terms of VSC production . Biofilms were examined in terms of ecological composition using culture‐dependent and independent (PCR‐DGGE) approaches.…”

“…The flat‐bed perfusion biofilm matrix was inoculated from a tongue biofilm sample (taken from one individual volunteer). One‐fifth strength brain heart infusion broth supplemented with haemin (0.0001%), cysteine (0.01% w/v) and di‐thiothreitol (0.005% w/v) and adjusted to pH 7.2 (± 0.2 units) was perfused into the matrix at a flow rate of 20 ml/h for 48 h to allow colonization and maturing of the biofilm to reach steady‐state, as determined in previous experiments . The biofilm module (see Figure ) was incubated at a temperature of 36°C ± 1°C and the gas flow rate (N 2 /CO 2 , 95/5 v/v%) was set at 50 ml/h.…”

In vitro efficacy of cold atmospheric pressure plasma on S. sanguinis biofilms in comparison of two test models

“…Wirthin et al [53] demonstrated that only after 100 h incubation time the steady state was reached. Despite the quantitative increase some authors consider biofilms after 48 h or even less incubation time as sufficient for routine experiments [8], [23], [46], [58], [66], [67]. A cell culture period of 72 hours is advantageous though, since resistance against antimicrobial agents was at its maximum after 72 h [64], [68] and the plaque milieu only becomes caries-producing after 72 h [1], [6], [39], [69], [70].…”

Abundance and Antibiotic Resistance of Cultivable Bacteria and Fungi on Ethiopian Cash-Money in Nekemte Town

“…From appropriate dilutions, 0.1 ml of the aliquot was spread plated on Plate Count Agar (PCA) and the plates were incubated at 35°C for 24 h. After incubation, plates with colonies between 30 and 300 were counted to estimate the abundances of aerobic mesophilic bacteria (AMB) [8]. Similarly, the diluents were spread-plate on Salmonella Shigella Agar (SSA), Xylose Lysine Deoxycholate (XLD) Agar, Eosin Methylene Blue (EMB) Agar, MacConkey (MAC) agar and incubated at 37°C for 24 h. After which, different types of colonies of bacteria with different colors like pink to red purple colonies on EMBA, Red to Black centered colonies on SSA and XLD Agar were counted as member of a family of Enterobacteriaceae [9]. A purplish colony surrounded by reddish zone on MAC agar and Metallic green sheen on EMB Agar were counted as Coliforms [8].…”