Extending an Eco-Evolutionary Understanding of Biofilm-Formation at the Air-Liquid Interface to Community Biofilms

ABSTRACT Enteropathogenic Escherichia coli (EPEC) is an important causal agent of diarrheal illness throughout the world. Nevertheless, researchers have only recently begun to explore its capacity to form biofilms. Strain O55:H7 (DMS9) is a clinical isolate belonging to the atypical EPEC (aEPEC) group, which displays a high degree of genetic relatedness to enterohemorrhagic E. coli. Strain DMS9 formed a robust biofilm on an abiotic surface at 26Ã¯Â¿Â½C, but not at 37Ã¯Â¿Â½C. It also formed a dense pellicle at the air-liquid interface and developed a red, rough, and dry (RDAR) morphotype on Congo red agar. Unlike a previously described E. coli O157:H7 strain, the aEPEC strain seems to express cellulose. Transposon mutagenesis was used to identify biofilm-deficient mutants. One of the mutants was inactivated in the csgFG genes, required for assembly and secretion of curli fimbriae, while a second mutant had a mutation in crl, a thermosensitive global regulator that modulates σS activity and downstream expression of curli and cellulose. The two mutants were deficient in their biofilm formation capabilities and did not form a pellicle at the air-liquid interface. Unlike in Salmonella, the csgFG mutant in aEPEC completely lost the RDAR phenotype, while the crl mutant displayed a unique RDAR “pizza”-like morphotype. Genetic complementation of the two mutants resulted in restoration of the wild-type phenotype. This report is the first to describe and analyze a multicellular behavior in aEPEC and support a major role for curli and the crl regulator in biofilm development at low temperatures corresponding to the nonmammalian host environment.

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Biofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons

Canadian Journal of Microbiology ◽

10.1139/cjm-2019-0554 ◽

2020 ◽

Vol 66 (4) ◽

pp. 328-336 ◽

Cited By ~ 3

Author(s):

Emmanuel W. Bumunang ◽

Collins N. Ateba ◽

Kim Stanford ◽

Tim A. McAllister ◽

Yan D. Niu

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

South African ◽

Food Processing ◽

Biofilm Formation ◽

Viable Cell ◽

Liquid Interface ◽

Cell Counts ◽

Potential Source ◽

Air Liquid Interface

This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air–liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air–liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.

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Comparison of the Genetic Features Involved in Bacillus subtilis Biofilm Formation Using Multi-Culturing Approaches

Microorganisms ◽

10.3390/microorganisms9030633 ◽

2021 ◽

Vol 9 (3) ◽

pp. 633

Author(s):

Yasmine Dergham ◽

Pilar Sanchez-Vizuete ◽

Dominique Le Coq ◽

Julien Deschamps ◽

Arnaud Bridier ◽

...

Keyword(s):

Bacillus Subtilis ◽

Biofilm Formation ◽

Negative Impact ◽

Liquid Interface ◽

Subtilis Strain ◽

Pellicle Formation ◽

Biofilm Model ◽

Genetic Features ◽

Semi Solid ◽

Air Liquid Interface

Surface-associated multicellular assemblage is an important bacterial trait to withstand harsh environmental conditions. Bacillus subtilis is one of the most studied Gram-positive bacteria, serving as a model for the study of genetic pathways involved in the different steps of 3D biofilm formation. B. subtilis biofilm studies have mainly focused on pellicle formation at the air-liquid interface or complex macrocolonies formed on nutritive agar. However, only few studies focus on the genetic features of B. subtilis submerged biofilm formation and their link with other multicellular models at the air interface. NDmed, an undomesticated B. subtilis strain isolated from a hospital, has demonstrated the ability to produce highly structured immersed biofilms when compared to strains classically used for studying B. subtilis biofilms. In this contribution, we have conducted a multi-culturing comparison (between macrocolony, swarming, pellicle, and submerged biofilm) of B. subtilis multicellular communities using the NDmed strain and mutated derivatives for genes shown to be required for motility and biofilm formation in pellicle and macrocolony models. For the 15 mutated NDmed strains studied, all showed an altered phenotype for at least one of the different culture laboratory assays. Mutation of genes involved in matrix production (i.e., tasA, epsA-O, cap, ypqP) caused a negative impact on all biofilm phenotypes but favored swarming motility on semi-solid surfaces. Mutation of bslA, a gene coding for an amphiphilic protein, affected the stability of the pellicle at the air-liquid interface with no impact on the submerged biofilm model. Moreover, mutation of lytF, an autolysin gene required for cell separation, had a greater effect on the submerged biofilm model than that formed at aerial level, opposite to the observation for lytABC mutant. In addition, B. subtilis NDmed with sinR mutation formed wrinkled macrocolony, less than that formed by the wild type, but was unable to form neither thick pellicle nor structured submerged biofilm. The results are discussed in terms of the relevancy to determine whether genes involved in colony and pellicle formation also govern submerged biofilm formation, by regarding the specificities in each model.

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Non-typeable Haemophilus influenzae biofilm formation on air-liquid interface cultured primary human airway epithelia

10.1183/13993003.congress-2021.pa2354 ◽

2021 ◽

Author(s):

Katie L Horton ◽

Raymond N Allan ◽

Janice L Coles ◽

Jana F Hueppe ◽

David W Cleary ◽

...

Keyword(s):

Haemophilus Influenzae ◽

Biofilm Formation ◽

Liquid Interface ◽

Airway Epithelia ◽

Human Airway ◽

Air Liquid Interface ◽

Human Airway Epithelia

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Air-Liquid Interface Biofilms of Bacillus cereus: Formation, Sporulation, and Dispersion

Applied and Environmental Microbiology ◽

10.1128/aem.01781-06 ◽

2007 ◽

Vol 73 (5) ◽

pp. 1481-1488 ◽

Cited By ~ 143

Author(s):

Janneke G. E. Wijman ◽

Patrick P. L. A. de Leeuw ◽

Roy Moezelaar ◽

Marcel H. Zwietering ◽

Tjakko Abee

Keyword(s):

Bacillus Cereus ◽

Biofilm Formation ◽

Culture Conditions ◽

Liquid Interface ◽

Production Cycle ◽

Microtiter Plates ◽

Production Environments ◽

Piping Systems ◽

Industrial Storage ◽

Air Liquid Interface

ABSTRACT Biofilm formation by Bacillus cereus was assessed using 56 strains of B. cereus, including the two sequenced strains, ATCC 14579 and ATCC 10987. Biofilm production in microtiter plates was found to be strongly dependent on incubation time, temperature, and medium, as well as the strain used, with some strains showing biofilm formation within 24 h and subsequent dispersion within the next 24 h. A selection of strains was used for quantitative analysis of biofilm formation on stainless steel coupons. Thick biofilms of B. cereus developed at the air-liquid interface, while the amount of biofilm formed was much lower in submerged systems. This suggests that B. cereus biofilms may develop particularly in industrial storage and piping systems that are partly filled during operation or where residual liquid has remained after a production cycle. Moreover, depending on the strain and culture conditions, spores constituted up to 90% of the total biofilm counts. This indicates that B. cereus biofilms can act as a nidus for spore formation and subsequently can release their spores into food production environments.

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Glycerol metabolism induces Listeria monocytogenes biofilm formation at the air-liquid interface

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2018.03.009 ◽

2018 ◽

Vol 273 ◽

pp. 20-27 ◽

Cited By ~ 10

Author(s):

Natalia Crespo Tapia ◽

Heidy M.W. den Besten ◽

Tjakko Abee

Keyword(s):

Listeria Monocytogenes ◽

Biofilm Formation ◽

Liquid Interface ◽

Glycerol Metabolism ◽

Air Liquid Interface

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Plant Polysaccharides Modulate Biofilm Formation and Insecticidal Activities of Bacillus thuringiensis Strains

Frontiers in Microbiology ◽

10.3389/fmicb.2021.676146 ◽

2021 ◽

Vol 12 ◽

Author(s):

Mengmeng Li ◽

Changlong Shu ◽

Wang Ke ◽

Xiaoxiao Li ◽

Yiyan Yu ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Growth Phase ◽

Biofilm Formation ◽

Insect Pests ◽

Liquid Interface ◽

Logarithmic Growth Phase ◽

Plant Polysaccharides ◽

Air Liquid Interface ◽

Logarithmic Growth ◽

Insecticidal Activities

After the biological pesticide Bacillus thuringiensis (Bt) is applied to the field, it has to remain on the surface of plants to have the insecticidal activities against insect pests. Bt can form biofilms on the surface of vegetable leaves, which were rich in polysaccharides. However, the relationship between polysaccharides of the leaves and the biofilm formation as well as the insecticidal activities of Bt is still unknown. Herein, this study focused on the effects of plant polysaccharides pectin and xylan on biofilm formation and the insecticidal activities of Bt strains. By adding pectin, there were 88 Bt strains with strong biofilm formation, 69 strains with weak biofilm formation, and 13 strains without biofilm formation. When xylan was added, 13 Bt strains formed strong biofilms, 98 strains formed weak biofilms, and 59 strains did not form biofilms. This indicated that two plant polysaccharides, especially pectin, modulate the biofilm formation of Bt strains. The ability of pectin to induce biofilm formation was not related to Bt serotypes. Pectin promoted the biofilms formed by Bt cells in the logarithmic growth phase and lysis phase at the air–liquid interface, while it inhibited the biofilms formed by Bt cells in the sporangial phase at the air–liquid interface. The dosage of pectin was positively correlated with the yield of biofilms formed by Bt cells in the logarithmic growth phase or lysis phase at the solid–liquid interfaces. Pectin did not change the free-living growth and the cell motility of Bt strains. Pectin can improve the biocontrol activities of the spore–insecticidal crystal protein mixture of Bt and BtK commercial insecticides, as well as the biofilms formed by the logarithmic growth phase or lysis phase of Bt cells. Our findings confirmed that plant polysaccharides modulate biofilm formation and insecticidal activities of Bt strains and built a foundation for the construction of biofilm-type Bt biopesticides.

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