Biofilms and human health

Srivastava, Shilpi; Bhargava, Atul

doi:10.1007/s10529-015-1960-8

Cited by 90 publications

(80 citation statements)

References 233 publications

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“…Previously, BTA was proven reliable to count microbial biofilm adherent to abiotic surfaces (Pantanella et al, 2008;De Giusti et al, 2011;Berlutti et al, 2014). Of note, BTA is performed without sample manipulation thus overcoming the bias related to CVC intra-luminal colonization and to vortex or sonication procedures (Freitas et al, 2014;Pantanella et al, 2013;Srivastava and Bhargava, 2016). In particular, vortex procedures do not guarantee the detachment of all microbes as confirmed by the data reported here (Fig.…”

Section: Discussionsupporting

confidence: 50%

“…It is evident that a rapid and reliable microbiological method for the early determination of CVC colonization is extremely important. BioTimer Assay (BTA) is a biological method that counts adherent bacteria and biofilm without sample manipulation as vortex or sonication to detach biomass and cultivation, thus overcoming the above-mentioned limits (Berlutti et al, 2003;Pantanella et al, 2008;Pantanella et al, 2011;Berlutti et al, 2014;Srivastava and Bhargava, 2016). In particular, BTA is based on the principle that a metabolic reaction will be faster when more bacteria are present in the sample.…”

Section: Introductionmentioning

confidence: 99%

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Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization

Rosa

Cutone

Coletti

et al. 2017

Journal of Microbiological Methods

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Adherent bacteria and biofilm frequently colonize central venous catheters (CVCs). CVC colonization is correlated to infections and particularly to bloodstream ones. The classical microbiological methods to determine of CVC colonization are not fully reliable and are time-consuming. BioTimer Assay (BTA) is a biological method already used to count bacteria adherent to abiotic surfaces and biofilm without sample manipulation. BTA employs specific reagents whose color changed according to bacterial metabolism. BTA is based on the principle that a metabolic reaction will be faster when more bacteria are present in the sample. Therefore, the time required for color changes of BTA reagents determines the number of bacteria present in the sample through a correlation line. Here, for the first time, we applied BTA and a specifically developed laboratory procedure to evaluate CVC colonization in comparison with the routine microbiological method (RMM). 125 CVCs removed from patients for suspected catheter-related bloodstream infection (CRBSI) or at hospital discharge were examined. BTA was reliable in assessing sterility and CVC colonization (100% agreement with RMM) and in recognizing the presence of fermenting or non-fermenting bacteria (97.1% agreement with RMM) shortening the analytical time by between 2- and 3-fold. Moreover, the reliability of BTA as early alert of CRBSI was evaluated. The sensitivity, specificity, positive, and negative predictive values for BTA as an early alert of CRBSI were 100, 40.0, 88.8 and 100%, respectively. In conclusion, BTA and the related laboratory procedure should be incorporated into routine microbiological methods since it can be considered a reliable tool to evaluate CVC colonization in a very short time and a rapid alert for CRBSIs.

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Section: Discussionsupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization

Rosa

Cutone

Coletti

et al. 2017

Journal of Microbiological Methods

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“…Such accumulation increases the possibility cell-surface attachment, facilitating undesirable secondary effects like biofouling and biofilm formation [11,12]. Surface-attached microbial communities [13,14] cause widespread problems to a broad range of industrial equipment and infrastructure, such as food processing facilities [15,16], ships and pipes [17], and surgical equipment and medical implants [18][19][20]. In the medical context, these surface-attached microbial colonies are especially harmful because they can lead to persistent infection [21].…”

Section: Introductionmentioning

confidence: 99%

Geometric control of bacterial surface accumulation

2019

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Controlling and suppressing bacterial accumulation at solid surfaces is essential for preventing biofilm formation and biofouling. Whereas various chemical surface treatments are known to reduce cell accumulation and attachment, the role of complex surface geometries remains less well understood. Here, we report experiments and simulations that explore the effects of locally varying boundary curvature on the scattering and accumulation dynamics of swimming Escherichia coli bacteria in quasi-two-dimensional microfluidic channels. Our experimental and numerical results show that a concave periodic boundary geometry can decrease the average cell concentration at the boundary by more than 50% relative to a flat surface.

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“…Additionally, there are alternative mechanisms that involve different key genes of the biofilm pathway, also leading to csgD activation and scale-up of curli fiber production; such as CpxR and ClpX which play a complex dual role during bacterium development to inhibit or activate both programs 8, 10, 13 . Undoubtedly, the interplay between these molecules acts to modulate the proper execution of the flagella-biofilm program 14, 15 . Experimentally, the transition between flagella and biofilm formation is evaluated using a “batch cells” assay, in which cells grow and attach to the chemically-inert surface of a microliter dish under static conditions, generating a biofilm in an “aquatic environment”.…”

Section: Introductionmentioning

confidence: 99%

Systematic identification of novel regulatory interactions controlling biofilm formation in the bacteriumEscherichia coli

Amores

Heras

Sanches-Medeiros

et al. 2017

Preprint

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50Here, we investigated novel interactions of three global regulators of the network that controls biofilm formation in the 51 model bacterium Escherichia coli using computational network analysis, an in vivo reporter assay and physiological 52 validation experiments. We were able to map critical nodes that govern planktonic to biofilm transition and identify 8 53 new regulatory interactions for CRP, IHF or Fis responsible for the control of the promoters of rpoS, rpoE, flhD, fliA, 54 csgD and yeaJ. Additionally, an in vivo promoter reporter assay and motility analysis revealed a key role for IHF as a 55 repressor of cell motility through the control of FliA sigma factor expression. This investigation of first stage and 56 mature biofilm formation indicates that biofilm structure is strongly affected by IHF and Fis, while CRP seems to 57 provide a fine-tuning mechanism. Taken together, the analysis presented here shows the utility of combining 58 computational and experimental approaches to generate a deeper understanding of the biofilm formation process in 59 bacteria. 60 _____________________________________________________________________________________________ 61 INTRODUCTION 62Bacteria shift from their free-swimming lifestyle to adopt a community structure to benefit from the micro-environment 63 created in a biofilm 1 , gaining protection against hazardous substances, and leading in some cases, to antibiotic 64 resistance 1, 2, 3 . It is well-understood that when differentiating from the planktonic to a biofilm structure bacteria transit 65 through specific stages, with each functional stage accompanied by changes to expression of specific genes of the 66 flagella-biofilm regulatory network 1, 2, 3 . In Escherichia coli, the complex transcriptional regulatory network of flagella 67 function and curli fimbriae production, the principal biofilm structure indicator, has been investigated in various 68 reports 4, 5, 6, 7 . In this organism, the process is controlled by the RpoS sigma factor and FlhDC regulator. These 69 master regulators receive major regulatory inputs from c-di-GMP, cAMP and ppGpp, which are modulated by a series 70 of environmental and physiological stresses 8, 9, 10 . In this sense, the flhDC genes are expressed at post-exponential 71 phase and their products control more than 60 genes involved in flagella synthesis and related functions, such as 72 chemotaxis 11 . Also at stationary phase, the general stress response master regulator RpoS is produced and controls 73. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/155432 doi: bioRxiv preprint first posted online Jun. 25, 2017; 3 over 500 genes in a highly complex regulatory network 7 . Therefore, the interplay between those master regulators 74 and downstream-activated genes modulates the complex transition between planktonic and biofilm stages. 75In the case of planktonic bacteria, mai...

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Biofilms and human health

Cited by 90 publications

References 233 publications

Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization

Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization

Geometric control of bacterial surface accumulation

Systematic identification of novel regulatory interactions controlling biofilm formation in the bacteriumEscherichia coli

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