scholarly journals Stochasticity of Bacterial Attachment and Its Predictability by the Extended Derjaguin-Landau-Verwey-Overbeek Theory

2011 ◽  
Vol 77 (11) ◽  
pp. 3757-3764 ◽  
Author(s):  
Teck Wah R. Chia ◽  
Vu Tuan Nguyen ◽  
Thomas McMeekin ◽  
Narelle Fegan ◽  
Gary A. Dykes
Keyword(s):  
Stainless Steel ◽  
Physicochemical Properties ◽  
Surface Properties ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Initial Ratio ◽  
Content Type ◽  
Initial Inoculum ◽  
Serovar Typhimurium ◽  
Attachment Process

ABSTRACTBacterial attachment onto materials has been suggested to be stochastic by some authors but nonstochastic and based on surface properties by others. We investigated this by attaching pairwise combinations of twoSalmonella entericaserovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each ofS. entericaserovar Typhimurium,S. entericaserovar Infantis, orS. entericaserovar Virchow (all with similar physicochemical and attachment abilities) in ratios of 0.428, 1, and 2.333 onto glass, stainless steel, Teflon, and polysulfone. Attached bacterial cells were recovered and counted. If the ratio of attached cells of eachSalmonellaserovar pair recovered was the same as the initial inoculum ratio, the attachment process was deemed stochastic. Experimental outcomes from the study were compared to those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Significant differences (P< 0.05) between the initial and the attached ratios for serovar pairs containingS. Sofia S1296a for all different ratios were apparent for all materials. ForS. Sofia S1635-containing pairs, 7 out of 12 combinations of serovar pairs and materials had attachment ratios not significantly different (P> 0.05) from the initial ratio of 0.428. Five out of 12 and 10 out of 12 samples had attachment ratios not significantly different (P> 0.05) from the initial ratios of 1 and 2.333, respectively. These results demonstrate that bacterial attachment to different materials is likely to be nonstochastic only when the key physicochemical properties of the bacteria were significantly different (P< 0.05) from each other. XDLVO theory could successfully predict the attachment of some individual isolates to particular materials but could not be used to predict the likelihood of stochasticity in pairwise attachment experiments.

Transfer of Salmonella and Campylobacter from Stainless Steel to Romaine Lettuce†

2003 ◽  
Vol 66 (12) ◽  
pp. 2231-2236 ◽  
Author(s):  
CHRISTINA M. MOORE ◽  
BRIAN W. SHELDON ◽  
LEE-ANN JAYKUS
Keyword(s):  
Stainless Steel ◽  
Salmonella Typhimurium ◽  
Sampling Period ◽  
Stainless Steel Surface ◽  
Inoculum Level ◽  
Drying Time ◽  
Initial Inoculum ◽  
Significant Difference ◽  
Serovar Typhimurium ◽  
Handling Practices

The degree of transfer of Campylobacter jejuni and Salmonella enterica serovar Typhimurium was evaluated from a stainless steel contact surface to a ready-to-eat food (lettuce). Stainless steel coupons (25 cm2) were inoculated with a 20-μl drop of either C. jejuni or Salmonella Typhimurium to provide an inoculum level of ~106 CFU/28 mm2. Wet and dry lettuce (Lactuca sativa var. longifolia) pieces (9 cm2) were placed onto the inoculated stainless steel surface for 10 s after the designated inoculum drying time (0 to 80 min for C. jejuni; 0 to 120 min for Salmonella Typhimurium), which was followed by the recovery and enumeration of transferred pathogens (lettuce) and residual surface pathogens (stainless steel coupons). For transfers of Salmonella Typhimurium to dry lettuce, there was an increase from 36 to 66% in the percent transfer of the initial inoculum load during the first 60 min of sampling and then a precipitous drop from 66 to 6% in percent transfer. The transfer of Salmonella Typhimurium to wet lettuce ranged from 23 to 31%, with no statistically significant difference between recoveries over the entire 120-min sampling period. For C. jejuni, the mean percent transfer ranged from 16 to 38% for dry lettuce and from 15 to 27% for wet lettuce during the 80-min sampling period. The results of this study indicate that relatively high numbers of bacteria may be transferred to a food even 1 to 2 h after surface contamination. These findings can be used to support future projects aimed at estimating the degree of risk associated with poor handling practices of ready-to-eat foods.

scholarly journals Clarithromycin Exerts an Antibiofilm Effect against Salmonella enterica Serovar Typhimurium rdar Biofilm Formation and Transforms the Physiology towards an Apparent Oxygen-Depleted Energy and Carbon Metabolism

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Munirah Zafar ◽  
Humera Jahan ◽  
Sulman Shafeeq ◽  
Manfred Nimtz ◽  
Lothar Jänsch ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Content Type ◽  
Regulatory Pathways ◽  
Heat Shock Stress ◽  
Extracellular Matrix Components ◽  
Serovar Typhimurium

ABSTRACT Upon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection toward various forms of environmental stresses to individual cells. Thus, bacterial cells within biofilms become tolerant against antimicrobials and the immune system. In the present study, we evaluated the antibiofilm activity of the macrolides clarithromycin and azithromycin. Clarithromycin showed antibiofilm activity against rdar (red, dry, and rough) biofilm formation of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium ATCC 14028 (Nalr) at a 1.56 μM subinhibitory concentration in standing culture and dissolved cell aggregates at 15 μM in a microaerophilic environment, suggesting that the oxygen level affects the activity of the drug. Treatment with clarithromycin significantly decreased transcription and production of the rdar biofilm activator CsgD, with biofilm genes such as csgB and adrA to be concomitantly downregulated. Although fliA and other flagellar regulon genes were upregulated, apparent motility was downregulated. RNA sequencing showed a holistic cell response upon clarithromycin exposure, whereby not only genes involved in the biofilm-related regulatory pathways but also genes that likely contribute to intrinsic antimicrobial resistance, and the heat shock stress response were differentially regulated. Most significantly, clarithromycin exposure shifted the cells toward an apparent oxygen- and energy-depleted status, whereby the metabolism that channels into oxidative phosphorylation was downregulated, and energy gain by degradation of propane 1,2-diol, ethanolamine and l-arginine catabolism, potentially also to prevent cytosolic acidification, was upregulated. This analysis will allow the subsequent identification of novel intrinsic antimicrobial resistance determinants.

Relationship between the Physicochemical Properties of Nonchitinolytic Listeria and Salmonella and Their Attachment to Shrimp Carapace

2009 ◽  
Vol 72 (6) ◽  
pp. 1181-1189 ◽  
Author(s):  
M. N. WAN NORHANA ◽  
REBECCA M. GOULTER ◽  
SUSAN E. POOLE ◽  
HILTON C. DEETH ◽  
GARY A. DYKES
Keyword(s):  
Cell Surface ◽  
Physicochemical Properties ◽  
Surface Charge ◽  
Foodborne Pathogens ◽  
Bacterial Species ◽  
Chitinase Activity ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Production Chain ◽  
Cell Surface Charge

Listeria and Salmonella are important foodborne pathogens normally associated with the shrimp production chain. This study investigated the potential of Salmonella Typhimurium, Salmonella Senftenberg, and Listeria monocytogenes (Scott A and V7) to attach to and colonize shrimp carapace. Attachment and colonization of Listeria and Salmonella were demonstrated. Shrimp abdominal carapaces showed higher levels of bacterial attachment (P &lt; 0.05) than did head carapaces. Listeria consistently exhibited greater attachment (P &lt; 0.05) than did Salmonella on all surfaces. Chitinase activity of all strains was tested and found not to occur at the three temperatures (10, 25, and 37°C) tested. The surface physicochemical properties of bacterial cells and shrimp carapace were studied to determine their role in attachment and colonization. Salmonella had significantly (P &lt; 0.05) more positive (−3.9 and −6.0 mV) cell surface charge than Listeria (−18 and −22.8 mV) had. Both bacterial species were found to be hydrophilic (&lt;35%) when measured by the bacterial adherence to hydrocarbon method and by contact angle (θ) measurements (Listeria, 21.3 and 24.8°, and Salmonella, 14.5 and 18.9°). The percentage of cells retained by Phenyl-Sepharose was lower for Salmonella (12.8 to 14.8%) than it was for Listeria (26.5 to 31.4%). The shrimp carapace was found to be hydrophobic (θ = 74.5°), and a significant (P &lt; 0.05) difference in surface roughness between carapace types was noted. There was a linear correlation between bacterial cell surface charge (r2 = 0.95) and hydrophobicity (r2 = 0.85) and initial attachment (P &lt; 0.05) of Listeria and Salmonella to carapaces. However, the same properties could not be related to subsequent colonization.

scholarly journals Loss of Culturability of Salmonella enterica subsp. enterica Serovar Typhimurium upon Cell-Cell Contact with Human Fecal Bacteria

2013 ◽  
Vol 79 (10) ◽  
pp. 3257-3263 ◽  
Author(s):  
Gaspar Avendaño-Pérez ◽  
Carmen Pin
Keyword(s):  
Salmonella Enterica ◽  
Mixed Cultures ◽  
Cell Contact ◽  
Data Sets ◽  
Fecal Bacteria ◽  
Bacterial Cells ◽  
Content Type ◽  
Serovar Typhimurium ◽  
A Cell ◽  
Mechanism Of Growth

ABSTRACTLoss of culturability ofSalmonella entericasubsp.entericaserovar Typhimurium has been observed in mixed cultures with anaerobic fecal bacteria under conditions that allow local interaction between cells, such as cell contact. A reduction of a population of culturableS.Typhimurium on the order of ∼104to 105CFU/ml was observed in batch anaerobic mixed cultures with fecal samples from different human donors. Culturability was not affected either in supernatants collected at several times from fecal cultures, when separated from fecal bacteria by a membrane of 0.45-μm pore size, or when in contact with inactivated fecal bacterial cells. Loss of culturability kinetics was characterized by a sharp reduction of several logarithmic units followed by a pronounced tail. A mathematical model was developed to describe the rate of loss of culturability as a function of the frequency of encounters between populations and the probability of inactivation after encounter. The model termF(S·F)1/2quantifies the effect of the concentration of both populations, fecal bacteria (F) andS.Typhimurium (S), on the loss of culturability ofS.Typhimurium by cell contact with fecal bacteria. When the value ofF(S·F)1/2decreased below ca. 1015(CFU/ml)2, the frequency of encounters sharply decreased, leading to the deceleration of the inactivation rate and to the tailing off of theS.Typhimurium population. The probability of inactivation after encounter,P, was constant, with an estimated value of ∼10−5for all data sets.Pmight be characteristic of the mechanism of growth inhibition after a cell encounter.

scholarly journals High-Content Imaging to Phenotype Antimicrobial Effects on Individual Bacteria at Scale

mSystems ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Sushmita Sridhar ◽  
Sally Forrest ◽  
Ben Warne ◽  
Mailis Maes ◽  
Stephen Baker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
High Resolution ◽  
Antimicrobial Resistance ◽  
Morphological Characteristics ◽  
Bacterial Cells ◽  
Bacterial Populations ◽  
Content Type ◽  
High Content Imaging ◽  
Serovar Typhimurium ◽  
Multiple Cells

ABSTRACT High-content imaging (HCI) is a technique for screening multiple cells in high resolution to detect subtle morphological and phenotypic variation. The method has been commonly deployed on model eukaryotic cellular systems, often for screening new drugs and targets. HCI is not commonly utilized for studying bacterial populations but may be a powerful tool in understanding and combatting antimicrobial resistance. Consequently, we developed a high-throughput method for phenotyping bacteria under antimicrobial exposure at the scale of individual bacterial cells. Imaging conditions were optimized on an Opera Phenix confocal microscope (Perkin Elmer), and novel analysis pipelines were established for both Gram-negative bacilli and Gram-positive cocci. The potential of this approach was illustrated using isolates of Klebsiella pneumoniae, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus. HCI enabled the detection and assessment of subtle morphological characteristics, undetectable through conventional phenotypical methods, that could reproducibly distinguish between bacteria exposed to different classes of antimicrobials with distinct modes of action (MOAs). In addition, distinctive responses were observed between susceptible and resistant isolates. By phenotyping single bacterial cells, we observed intrapopulation differences, which may be critical in identifying persistence or emerging resistance during antimicrobial treatment. The work presented here outlines a comprehensive method for investigating morphological changes at scale in bacterial populations under specific perturbation. IMPORTANCE High-content imaging (HCI) is a microscopy technique that permits the screening of multiple cells simultaneously in high resolution to detect subtle morphological and phenotypic variation. The power of this methodology is that it can generate large data sets comprised of multiple parameters taken from individual cells subjected to a range of different conditions. We aimed to develop novel methods for using HCI to study bacterial cells exposed to a range of different antibiotic classes. Using an Opera Phenix confocal microscope (Perkin Elmer) and novel analysis pipelines, we created a method to study the morphological characteristics of Klebsiella pneumoniae, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus when exposed to antibacterial drugs with differing modes of action. By imaging individual bacterial cells at high resolution and scale, we observed intrapopulation differences associated with different antibiotics. The outlined methods are highly relevant for how we begin to better understand and combat antimicrobial resistance.

scholarly journals Determining the Development of Persisters in Extensively Drug-Resistant Acinetobacter baumannii upon Exposure to Polymyxin B-Based Antibiotic Combinations Using Flow Cytometry

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Fiona Hui-Sian Wong ◽  
Yiying Cai ◽  
Hui Leck ◽  
Tze-Peng Lim ◽  
Jocelyn Qi-Min Teo ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Acinetobacter Baumannii ◽  
Polymyxin B ◽  
Live Cells ◽  
Drug Resistant ◽  
Bacterial Cells ◽  
Persister Cells ◽  
Content Type ◽  
Initial Inoculum ◽  
Extensively Drug Resistant

ABSTRACT Polymyxin B-based combinations are increasingly prescribed as a last-line option against extensively drug-resistant (XDR) Acinetobacter baumannii. It is unknown if such combinations can result in the development of nondividing persister cells in XDR A. baumannii. We investigated persister development upon exposure of XDR A. baumannii to polymyxin B-based antibiotic combinations using flow cytometry. Time-kill studies (TKSs) were conducted in three nonclonal XDR A. baumannii strains with 5 log10 CFU/ml bacteria against polymyxin B alone and polymyxin B-based two-drug combinations over 24 h. At different time points, samples were obtained and enumerated by viable plating and flow cytometry. Propidium iodide and carboxyfluorescein succinimidyl ester dyes were used to differentiate between live and dead cells and between dividing and nondividing cells, respectively, at the single-cell level, and nondividing live cells were resuscitated and characterized phenotypically. Our results from viable plating showed that polymyxin B plus meropenem and polymyxin B plus rifampin were each bactericidal (>99.9% kill compared to the initial inoculum) against 2/3 XDR A. baumannii strains at 24 h. By flow cytometry, however, none of the combinations were bactericidal against XDR A. baumannii at 24 h. Further analysis using cellular dyes in flow cytometry revealed that upon exposure to polymyxin B-based combinations, XDR A. baumannii entered a viable but nondividing persister state. These bacterial cells reinitiated division upon the removal of antibiotic pressure and did not have a growth deficit compared to the parent strain. We conclude that persister cells develop in XDR A. baumannii upon exposure to polymyxin B-based combinations and that nonplating methods appear to complement viable-plating methods in describing the killing activity of polymyxin B-based combinations against XDR A. baumannii.

scholarly journals Influence of Substrate Mineralogy on Bacterial Mineralization of Calcium Carbonate: Implications for Stone Conservation

2012 ◽  
Vol 78 (11) ◽  
pp. 4017-4029 ◽  
Author(s):  
Carlos Rodriguez-Navarro ◽  
Fadwa Jroundi ◽  
Mara Schiro ◽  
Encarnación Ruiz-Agudo ◽  
María Teresa González-Muñoz
Keyword(s):  
Calcium Carbonate ◽  
Culture Conditions ◽  
Building Stone ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Calcium Carbonate Precipitation ◽  
Stone Conservation ◽  
Historical Building ◽  
Content Type ◽  
Polymorph Selection

ABSTRACTThe influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P) inoculated with different types of bacteria (Myxococcus xanthus,Brevundimonas diminuta, and a carbonatogenic bacterial community isolated from porous calcarenite stone in a historical building) and direct application of sterile M-3P medium to limestone and sandstone with their own bacterial communities. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD), and 2-dimensional XRD (2D-XRD) analyses revealed that abundant highly oriented calcite crystals formed homoepitaxially on the calcitic substrates, irrespective of the bacterial type. Conversely, scattered spheroidal vaterite entombing bacterial cells formed on the silicate substrates. These results show that carbonate phase selection is not strain specific and that under equal culture conditions, the substrate type is the overruling factor for calcium carbonate polymorph selection. Furthermore, carbonate productivity is strongly dependent on the mineralogy of the substrate. Calcitic substrates offer a higher affinity for bacterial attachment than silicate substrates, thereby fostering bacterial growth and metabolic activity, resulting in higher production of calcium carbonate cement. Bacterial calcite grows coherently over the calcitic substrate and is therefore more chemically and mechanically stable than metastable vaterite, which formed incoherently on the silicate substrates. The implications of these results for technological applications of bacterial carbonatogenesis, including building stone conservation, are discussed.

scholarly journals Effect of Micro- and Nanoscale Topography on the Adhesion of Bacterial Cells to Solid Surfaces

2013 ◽  
Vol 79 (8) ◽  
pp. 2703-2712 ◽  
Author(s):  
Lillian C. Hsu ◽  
Jean Fang ◽  
Diana A. Borca-Tasciuc ◽  
Randy W. Worobo ◽  
Carmen I. Moraru
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Bacterial Attachment ◽  
Listeria Innocua ◽  
Solid Surfaces ◽  
Bacterial Cells ◽  
Content Type ◽  
Nanoscale Topography ◽  
Key Microorganisms ◽  
Financial Losses

ABSTRACTAttachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, includingEscherichia coli,Listeria innocua, andPseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.

scholarly journals Removing biofilms from stainless steel without changing surface properties relevant for bacterial attachment

2017 ◽  
Vol 12 (2) ◽  
pp. 02C404 ◽  
Author(s):  
Katharina Huttenlochner ◽  
Christine Müller-Renno ◽  
Christiane Ziegler ◽  
Rolf Merz ◽  
Birgit Merz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Surface Properties ◽  
Bacterial Attachment

Comparison of spindle and stomacher efficacy for detaching biofilms from stainless steel, PVC, and green leafy vegetable surfaces

2019 ◽  
Vol 122 (2) ◽  
pp. 503-514
Author(s):  
Wooju Kim ◽  
Ki-Ok Jeong ◽  
Ho-Lyeong Cheon ◽  
Dong-Hyun Kang
Keyword(s):  
Stainless Steel ◽  
Bacterial Communities ◽  
Food Industry ◽  
Design Methodology ◽  
Bacterial Cells ◽  
Comparative Experiment ◽  
Content Type ◽  
Green Leafy Vegetable ◽  
Abiotic Surfaces ◽  
Significant Difference

Purpose Biofilms are bacterial communities embedded in exopolysaccharide, enhancing the difficulty of detaching bacterial cells from surfaces. Due to structural properties, it is difficult to detach biofilms. Many removal methods have been developed, but there are still some limitations such as sample size and reproducibility. “Spindle” was developed, producing a higher quality suspension which can be used for further study. The paper aims to discuss these issues. Design/methodology/approach The authors compared the enumeration of biofilm-forming cells detached from the spindle and stomacher in various surfaces. First, the authors chose stainless steel and polyvinyl chloride to attach biofilms and to be subjected to stomacher and spindle for up to 2 min. Also, the authors evaluated the efficiency of detachment from vegetable surfaces. Findings In a comparative experiment of abiotic surfaces, the spindle showed identical effectiveness for detaching biofilm-forming cells compared to the stomacher, recovering the population by 8-log for Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The spindle also showed no significant difference from the stomacher in the number of recovered cells which is 4-log from vegetable surfaces. However, turbidity after spinach was subjected to spindle was 4.37 NTU, while it was 99 NTU for stomacher, which was in accord with visual result about clearance. Originality/value This study demonstrated that the spindle is a useful to separate biofilms from surfaces without destructing structure, and thus it can be used for analysis in food laboratories as well as utilized for vegetable washing step in the food industry.

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