Biofilm development by Listeria innocua in turbulent flow regimes

Perni, Stefano; Jordan, Suzanne J.; Andrew, Peter W.; Shama, Gilbert

doi:10.1016/j.foodcont.2005.06.002

Cited by 32 publications

(23 citation statements)

References 38 publications

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“…Flocs that are important in successful wastewater treatment were removed and then a mixed supernatant, comprising planktonic bacteria, was cultured for 24 h before it was inoculated into the high-shear bioreactor. The clustering patterns observed were also observed in previous studies [73][74][75], but the positive and strong correlation between clustering and shear is novel and the level of turbulence in the flow developed to induce such high shear flows is unique in biofilm colonisation studies. The mechanisms suggested to be important for the clustering patterns are co-adhesion [76], which occurs on the substratum and describes the propensity for bacteria to attach in proximity to those that have already attached, and coaggregation [77], which is the coming-together of bacteria in clumps in the bulk water prior to adhesion onto the surface.…”

Section: Discussionsupporting

confidence: 78%

A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

Tsagkari

Keating

Couto

et al. 2017

Water

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Abstract:The structure of biofilms in drinking water systems is influenced by the interplay between biological and physical processes. Bacterial aggregates in bulk fluid are important in seeding biofilm formation on surfaces. In simple pure and co-cultures, certain bacteria, including Methylobacterium, are implicated in the formation of aggregates. However, it is unclear whether they help to form aggregates in complex mixed bacterial communities. Furthermore, different flow regimes could affect the formation and destination of aggregates. In this study, real drinking water mixed microbial communities were inoculated with the Methylobacterium strain DSM 18358. The propensity of Methylobacterium to promote aggregation was monitored under both stagnant and flow conditions. Under stagnant conditions, Methylobacterium enhanced bacterial aggregation even when it was inoculated in drinking water at 1% relative abundance. Laminar and turbulent flows were developed in a rotating annular reactor. Methylobacterium was found to promote a higher degree of aggregation in turbulent than laminar flow. Finally, fluorescence in situ hybridisation images revealed that Methylobacterium aggregates had distinct spatial structures under the different flow conditions. Overall, Methylobacterium was found to be a key strain in the formation of aggregates in bulk water and subsequently in the formation of biofilms on surfaces.

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Section: Discussionsupporting

confidence: 78%

A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

Tsagkari

Keating

Couto

et al. 2017

Water

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“…Therefore, the biofilm formation depends on the variation of the substances concentration and on the flow conditions at the surface and on the culture medium turbulence (Perni et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Study of kefir biofilm associated with hydroethanolic extract of Euterpe oleracea Mart. (aai)

Oliveira¹,

Maciel²,

Florentino³

et al. 2017

Afr. J. Microbiol. Res.

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Kefir is a microbial complex capable of producing biofilms. This study aims to obtain biofilms associated with hydroethanolic extract of Euterpe oleracea Mart. (BEHEEo) as fixing method of recovery anthocyanins in kefir biofilm. Thus, BEHEEo formation kinetics was made at different concentrations of aqueous extract of E. oleracea, of kefir grains (KG) and of brown sugar (BS). Thereafter, macro and microelements of BEHEEo were determined; the rheological and structural characteristics were analyzed using atomic force microscopy (AFM), and anthocyanins dosage in BEHEEo was obtained. The best concentration of BS to form BEHEEo was 40 g/l with 100 ml of EHEEo (12.62±0.16 g), as well as a release of the BEHEEo anthocyanins occurring after 5 min (4.3±0.6 mg/100 g) with maximum peak at 60 min (20.8±0.3). The concentration of calcium iron and magnesium was 0.089, 0.1740 and 0.1808 mg/kg, respectively, indicating the concentration of Zn2+ which was 0.533 mg/kg. The AFM analysis revealed differences in the peaks of roughness depending on the concentration of kefir grains, with presence of Lactobacillus and yeast. The concentration of anthocyanins in BEHEEo two years after the incorporation was 26 mg/100 g. Therefore, it is suggested that the BEHEEo incorporating EHEEo anthocyanins has potential for therapeutic applications in several pathologies necessary for antioxidative processes.Key words: Biofilms, kefir, açaí, Euterpe oleracea Mart., anthocyanins, atomic force microscopy (AFM). INTRODUCTIONKefir is a beverage produced by fermenting substrates such as milk or sugar water by kefir grains (Rodrigues et al., 2005;Laureys and De Vuyst, 2014). The growth and the function of bacteria inside a population are crucial for their survival (Davey and O'toole, 2000). In kefir, there is a predominance of Lactobacillus which has high catabolic capacity and is complemented by yeast with high biosynthetic capacity.When growing kefir in water for more than twenty days, there is the formation of biofilms with therapeutic properties against pathogenic organisms. These biofilms are surfaces with a high rate of structural organization associated with bacterial colonies held together by a polymer secreted by their cells, which is called extracellular polymeric substance (EPS) (Watnick and Kolter, 2000, Donlan, 2002;Zhang et al., 2015). Among many strategies used for the study of biofilms, the one that is more highlighted is the use of the Atomic Force Microscopy (AFM), which allows measurement of the interaction forces between cells or cell-cell interactions (Dufrêne, 2015).One of the substances that have been intensified in recent years are the anthocyanins, due to their protective and healing properties. Anthocyanins have an important role in physiological functions related to human health (Lee et al., 2013). The antioxidant effect of anthocyanins have been known and proven fact. The action mechanism of the anthocyanin is inhibiting the free radicals that promote oxidation. The antioxidant agents capable of binding to the free radicals ...

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“…They are preferentially formed in wet environments (e.g., insufficient drying of endoscopes before storage [124,125] ), can form under different flow conditions [126,127] and can be potential sources of contamination and infection [128] . Virtually all bacterial species can form biofilm including clinically-relevant ones such as P. aeruginosa, S. aureus, E. coli and Clostridium difficile [123,129,130] .…”

Section: General Backgroundmentioning

confidence: 99%

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

Kampf

Fliss

Martiny

2014

WJGE

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The bioburden (blood, protein, pathogens and biofilm) on flexible endoscopes after use is often high and its removal is essential to allow effective disinfection, especially in the case of peracetic acid-based disinfectants, which are easily inactivated by organic material. Cleaning processes using conventional cleaners remove a variable but often sufficient amount of the bioburden. Some formulations based on peracetic acid are recommended by manufacturers for the cleaning step. We performed a systematic literature search and reviewed the available evidence to clarify the suitability of peracetic acid-based formulations for cleaning flexible endoscopes. A total of 243 studies were evaluated. No studies have yet demonstrated that peracetic acidbased cleaners are as effective as conventional cleaners. Some peracetic acid-based formulations have demonstrated some biofilm-cleaning effects and no biofilmfixation potential, while others have a limited cleaning effect and a clear biofilm-fixation potential. All published data demonstrated a limited blood cleaning effect and a substantial blood and nerve tissue fixation potential of peracetic acid. No evidence-based guidelines on reprocessing flexible endoscopes currently recommend using cleaners containing peracetic acid, but some guidelines clearly recommend not using them because of their fixation potential. Evidence from some outbreaks, especially those involving highly multidrug-resistant gram-negative pathogens, indicated that disinfection using peracetic acid may be insufficient if the preceding cleaning step is not performed adequately. Based on this review we conclude that peracetic acid-based formulations should not be used for cleaning flexible endoscopes. Key words: Peracetic acid; Cleaning; Flexible endoscope; Biofilm; Resistance; Bioburden; Blood; Disinfection; Reprocessing Core tip: Some formulations based on peracetic acid (PAA) are recommended by manufacturers for cleaning flexible endoscopes. We reviewed 243 studies to analyse the evidence for this recommendation. No study demonstrated that PAA-based cleaners were as effective as conventional cleaners, and some PAA-based formulations had clear biofilm-fixation potential. Dried blood and nerve tissue were substantially fixed by PAA. Some outbreaks, especially of highly multidrug-resistant gram-negative pathogens, indicated that insufficient cleaning could not be compensated for by using PAA in the disinfection step. PAA-based formulations should not be used for cleaning flexible endoscopes.

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Biofilm development by Listeria innocua in turbulent flow regimes

Cited by 32 publications

References 38 publications

A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

Study of kefir biofilm associated with hydroethanolic extract of Euterpe oleracea Mart. (aai)

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

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