scholarly journals Antimicrobial Susceptibility of Persister Biofilm Cells of Bacillus cereus and Pseudomonas fluorescens

2022 ◽  
Vol 10 (1) ◽  
pp. 160
Author(s):  
Susana Fernandes ◽  
Inês B. Gomes ◽  
Sérgio F. Sousa ◽  
Manuel Simões
Keyword(s):  
Bacillus Cereus ◽  
Pseudomonas Fluorescens ◽  
Antimicrobial Susceptibility ◽  
Peracetic Acid ◽  
Benzalkonium Chloride ◽  
Glycolic Acid ◽  
Persister Cells ◽  
Vegetative Cells ◽  
Biocide Treatment

The present study evaluates the antimicrobial susceptibility of persister cells of Bacillus cereus and Pseudomonas fluorescens after their regrowth in suspension and as biofilms. Two conventional (benzalkonium chloride—BAC and peracetic acid—PAA) and two emerging biocides (glycolic acid—GA and glyoxal—GO) were selected for this study. Persister cells resulted from biofilms subjected to a critical treatment using the selected biocides. All biocide treatments developed B. cereus persister cells, except PAA that effectively reduced the levels of vegetative cells and endospores. P. fluorescens persister cells comprise viable and viable but non-culturable cells. Afterwards, persister cells were regrown in suspension and in biofilms and were subjected to a second biocide treatment. In general, planktonic cultures of regrown persister cells in suspension lost their antimicrobial tolerance, for both bacteria. Regrown biofilms of persister cells had antimicrobial susceptibility close to those regrown biofilms of biocide-untreated cells, except for regrown biofilms of persister P. fluorescens after BAC treatment, which demonstrated increased antimicrobial tolerance. The most active biocide against persister cells was PAA, which did not promote changes in susceptibility after their regrowth. In conclusion, persister cells are ubiquitous within biofilms and survive after critical biocide treatment. The descendant planktonic and biofilms populations showed similar properties as the original ones.

scholarly journals Comparative Transcriptomic and Phenotypic Analysis of the Responses of Bacillus cereus to Various Disinfectant Treatments

2010 ◽  
Vol 76 (10) ◽  
pp. 3352-3360 ◽  
Author(s):  
Mara Ceragioli ◽  
Maarten Mols ◽  
Roy Moezelaar ◽  
Emilia Ghelardi ◽  
Sonia Senesi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Fatty Acid ◽  
Bacillus Cereus ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Benzalkonium Chloride ◽  
Membrane Damage ◽  
Sos Response ◽  
Transcriptional Responses ◽  
Induced Genes

ABSTRACT Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four different disinfectants (benzalkonium chloride, sodium hypochlorite, hydrogen peroxide, and peracetic acid) were analyzed. For each disinfectant, concentrations leading to the attenuation of growth, growth arrest, and cell death were determined. The transcriptome analysis revealed that B. cereus, upon exposure to the selected concentrations of disinfectants, induced common and specific responses. Notably, the common response included genes involved in the general and oxidative stress responses. Exposure to benzalkonium chloride, a disinfectant known to induce membrane damage, specifically induced genes involved in fatty acid metabolism. Membrane damage induced by benzalkonium chloride was confirmed by fluorescence microscopy, and fatty acid analysis revealed modulation of the fatty acid composition of the cell membrane. Exposure to sodium hypochlorite induced genes involved in metabolism of sulfur and sulfur-containing amino acids, which correlated with the excessive oxidation of sulfhydryl groups observed in sodium hypochlorite-stressed cells. Exposures to hydrogen peroxide and peracetic acid induced highly similar responses, including the upregulation of genes involved in DNA damage repair and SOS response. Notably, hydrogen peroxide- and peracetic acid-treated cells exhibited high mutation rates correlating with the induced SOS response.

Sidrophore Production and Phosphate Solubilization by Bacillus cereus and Pseudomonas fluorescens Isolated from Iraqi Soils and Soil Characterization

2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Zaid Raad Abbas ◽  
Aqeel Mohammed Majeed Al-Ezee ◽  
Sawsan H
Keyword(s):  
Bacillus Cereus ◽  
Pseudomonas Fluorescens ◽  
Phosphate Solubilization ◽  
Bacterial Species ◽  
Nutrient Status ◽  
Bacterial Count ◽  
Soil Samples ◽  
Phosphate Solubilizing Bacteria ◽  
Clear Zone ◽  
Zone Formation

This study was conducted to explore the ability of Pseudomonas fluorescens and Bacillus cereus to solubilizing a phosphate in soil for enhancing the planting growth and, its relation with soill characterization. The isolates were identified as P.fluorescens and B. cereus using convential analysis and, its phosphate solubilization ability and sidrophore was shown by the clear zone formation on National Botanical Research Institute���s Phosphate medium. Moreover, Pseudomonas fluorescens isolates (n = 9) and three of B. cereus isolated from agricultural area in Baghdad university, Mustansiriyah university and Diyala bridge. Results displayed that bacterial count were varied in soil samples according to their region, and ranging from 30 to 60 *10 2 CFU/g in Baghdad university soil to 10���20 *10 2 CFU/g in Mustansiriyah university soil, the Baghdad soil macronutrient which included: NH4, NO3, P, and K were, 8.42, 20.53, 19.09, 218.73 respectively, While the physio analysis revealed that the mean of pH was 7.3 and EC was 8.63. on the other hand the micronutrient analysis indicated that the soil samples were included Ca, Fe, Mn, Zn and Cu which gave their mean 5025.9, 8.9, 4.9, 0.5 and 1.5 respectevily. Results revealed that all isolated bacteria (9 isolates of P.fluorescens and three isolates of B. cereus gave ahalo zone which mean their ability to be phosphate solubilizing bacteria at 100%. Results revealed that all isolated bacteria were detected a ability to produce high levels from chelating agents (siderophores)) by P.fluorescens and. B cereus at 100%, when appeared ahalo clear zone. Furthermore, the high levels of phosphate solubilization and siderophore production were grouped in bacterial species isolated from Iraqi soils. might be attributed to many soil factors such as soil nutrient status, soil acidity, water content, organic matter and soil enzyme activities.

Film coating of seeds with Bacillus cereus RS87 spores for early plant growth enhancement

2008 ◽  
Vol 54 (10) ◽  
pp. 861-867 ◽  
Author(s):  
Kanchalee Jetiyanon ◽  
Sakchai Wittaya-Areekul ◽  
Pinyupa Plianbangchang
Keyword(s):  
Plant Growth ◽  
Bacillus Cereus ◽  
Plant Height ◽  
Root Length ◽  
Film Coating ◽  
Field Trials ◽  
Growth Enhancement ◽  
Vegetative Cells ◽  
Plant Growth Promoting ◽  
Growth Promoting

The plant growth-promoting rhizobacterium Bacillus cereus RS87 was previously reported to promote plant growth in various crops in both greenhouse and field trials. To apply as a plant growth promoting agent with practical use, it is essential to ease the burden of routine preparation of a fresh suspension of strain RS87 in laboratory. The objectives of this study were to investigate the feasibility of film-coating seeds with B. cereus RS87 spores for early plant growth enhancement and to reveal the indoleacetic acid (IAA) production released from strain RS87. The experiment consisted of the following 5 treatments: nontreated seeds, water-soaked seeds, film-coated seeds, seeds soaked with vegetative cells of strain RS87, and film-coated seeds with strain RS87 spores. Three experiments were conducted separately to assess seed emergence, root length, and plant height. Results showed that both vegetative cells and spores of strain RS87 significantly promoted (P ≤ 0.05) seed emergence, root length and plant height over the control treatments. The strain RS87 also produced IAA. In conclusion, the film coating of seeds with spores of B. cereus RS87 demonstrated early plant growth enhancement as well as seeds using their vegetative cells. IAA released from strain RS87 would be one of the mechanisms for plant growth enhancement.

Inactivation kinetics of Bacillus cereus vegetative cells and spores from different sources by antimicrobial photodynamic treatment (aPDT)

LWT ◽  
2021 ◽  
Vol 142 ◽  
pp. 111037
Author(s):  
Leonardo do Prado-Silva ◽  
Verônica O. Alvarenga ◽  
Gilberto Ú.L. Braga ◽  
Anderson S. Sant’Ana
Keyword(s):  
Bacillus Cereus ◽  
Inactivation Kinetics ◽  
Photodynamic Treatment ◽  
Vegetative Cells ◽  
Kinetics Of ◽  
Different Sources

scholarly journals HrcA and DnaK are important for static and continuous-flow biofilm formation and disinfectant resistance in Listeria monocytogenes

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3782-3790 ◽  
Author(s):  
Stijn van der Veen ◽  
Tjakko Abee
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Peracetic Acid ◽  
Continuous Flow ◽  
Biofilm Formation ◽  
Benzalkonium Chloride ◽  
Wild Type ◽  
Shock Response ◽  
Disinfectant Resistance

The food-borne pathogen Listeria monocytogenes is able to form biofilms in food processing environments. Since biofilms are generally difficult to eradicate during clean-up procedures, they pose a major risk for the food industry. Stress resistance mechanisms involved in L. monocytogenes biofilm formation and disinfectant resistance have, to our knowledge, not been identified thus far. In this study, we investigated the role of hrcA, which encodes the transcriptional regulator of the class I heat-shock response, and dnaK, which encodes a class I heat-shock response chaperone protein, in static and continuous-flow biofilm formation and resistance against benzalkonium chloride and peracetic acid. Induction of both hrcA and dnaK during continuous-flow biofilm formation was observed using quantitative real-time PCR and promoter reporters. Furthermore, in-frame deletion and complementation mutants of hrcA and dnaK revealed that HrcA and DnaK are required to reach wild-type levels of both static and continuous-flow biofilms. Finally, disinfection treatments of planktonic-grown cells and suspended static and continuous-flow biofilm cells of wild-type and mutants showed that HrcA and DnaK are important for resistance against benzalkonium chloride and peracetic acid. In conclusion, our study revealed that HrcA and DnaK are important for L. monocytogenes biofilm formation and disinfectant resistance.

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