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  1. Fulltext In vitro assessment of Pediococcus acidilactici Kp10 for its potential use in the food industry
    Abbasiliasi S, Tan JS, Bashokouh F, Ibrahim TAT, Mustafa S, Vakhshiteh F, et al.
    BMC Microbiol, 2017 May 23;17(1):121.
    PMID: 28535747 DOI: 10.1186/s12866-017-1000-z
    BACKGROUND: Selection of a microbial strain for the incorporation into food products requires in vitro and in vivo evaluations. A bacteriocin-producing lactic acid bacterium (LAB), Pediococcus acidilactici Kp10, isolated from a traditional dried curd was assessed in vitro for its beneficial properties as a potential probiotic and starter culture. The inhibitory spectra of the bacterial strain against different gram-positive and gram-negative bacteria, its cell surface hydrophobicity and resistance to phenol, its haemolytic, amylolytic and proteolytic activities, ability to produce acid and coagulate milk together with its enzymatic characteristics and adhesion property were all evaluated in vitro.

    RESULTS: P. acidilactici Kp10 was moderately tolerant to phenol and adhere to mammalian epithelial cells (Vero cells and ileal mucosal epithelium). The bacterium also exhibited antimicrobial activity against several gram-positive and gram-negative food-spoilage and food-borne pathogens such as Listeria monocytgenes ATCC 15313, Salmonella enterica ATCC 13311, Shigella sonnei ATCC 9290, Klebsiella oxytoca ATCC 13182, Enterobacter cloaca ATCC 35030 and Streptococcus pyogenes ATCC 12378. The absence of haemolytic activity and proteinase (trypsin) and the presence of a strong peptidase (leucine-arylamidase) and esterase-lipase (C4 and C8) were observed in this LAB strain. P. acidilactici Kp10 also produced acid, coagulated milk and has demonstrated proteolytic and amylolactic activities.

    CONCLUSION: The properties exhibited by P. acidilactici Kp10 suggested its potential application as probiotic and starter culture in the food industry.

    Matched MeSH terms: Bacterial Adhesion
  2. Alternative sweeteners influence the biomass of oral biofilm
    Abdul Razak F, Baharuddin BA, Akbar EFM, Norizan AH, Ibrahim NF, Musa MY
    Arch Oral Biol, 2017 Aug;80:180-184.
    PMID: 28448807 DOI: 10.1016/j.archoralbio.2017.04.014
    OBJECTIVE: Compact-structured oral biofilm accumulates acids that upon prolonged exposure to tooth surface, causes demineralisation of enamel. This study aimed to assess the effect of alternative sweeteners Equal Stevia(®), Tropicana Slim(®), Pal Sweet(®) and xylitol on the matrix-forming activity of plaque biofilm at both the early and established stages of formation.

    METHODS: Saliva-coated glass beads (sGB) were used as substratum for the adhesion of a mixed-bacterial suspension of Streptococcus mutans, Streptococcus sanguinis and Streptococcus mitis. Biofilms formed on sGB at 3h and 24h represented the early and established-plaque models. The biofilms were exposed to three doses of the sweeteners (10%), introduced at three intervals to simulate the exposure of dental plaque to sugar during three consecutive food intakes. The treated sGB were (i) examined under the SEM and (ii) collected for turbidity reading. The absorbance indicated the amount of plaque mass produced. Analysis was performed comparative to sucrose as control.

    RESULTS: Higher rate of bacterial adherence was determined during the early compared to established phases of formation. Comparative to the sweeteners, sucrose showed a 40% increase in bacterial adherence and produced 70% more plaque-mass. Bacterial counts and SEM micrographs exhibited absence of matrix in all the sweetener-treated biofilms at the early phase of formation. At the established phase, presence of matrix was detected but at significantly lower degree compared to sucrose (p<0.05).

    CONCLUSION: Alternatives sweeteners promoted the formation of oral biofilm with lighter mass and lower bacterial adherence. Hence, suggesting alternative sweeteners as potential antiplaque agents.

    Matched MeSH terms: Bacterial Adhesion
  3. Anti-plaque effect of a synergistic combination of green tea and Salvadora persica L. against primary colonizers of dental plaque
    Abdulbaqi HR, Himratul-Aznita WH, Baharuddin NA
    Arch Oral Biol, 2016 Oct;70:117-124.
    PMID: 27343694 DOI: 10.1016/j.archoralbio.2016.06.011
    OBJECTIVE: Green tea (Gt), leafs of Camellia sinensis var. assamica, is widely consumed as healthy beverage since thousands of years in Asian countries. Chewing sticks (miswak) of Salvadora persica L. (Sp) are traditionally used as natural brush to ensure oral health in developing countries. Both Gt and Sp extracts were reported to have anti-bacterial activity against many dental plaque bacteria. However, their combination has never been tested to have anti-bacterial and anti-adherence effect against primary dental plaque colonizers, playing an initial role in the dental plaque development, which was investigated in this study.

    METHODS: Two-fold serial micro-dilution method was used to measure minimal inhibitory concentration (MIC) of aqueous extracts of Gt, Sp and their combinations. Adsorption to hexadecane was used to determine the cell surface hydrophobicity (CSH) of bacterial cells. Glass beads were used to mimic the hard tissue surfaces, and were coated with saliva to develop experimental pellicles for the adhesion of the primary colonizing bacteria.

    RESULTS: Gt aqueous extracts exhibited better anti-plaque effect than Sp aqueous extracts. Their combination, equivalent to 1/4 and 1/2 of MIC values of Gt and Sp extracts respectively, showed synergistic anti-plaque properties with fractional inhibitory concentration (FIC) equal to 0.75. This combination was found to significantly reduce CSH (p<0.05) and lower the adherence ability (p<0.003) towards experimental pellicles.

    CONCLUSION: Combination between Gt and Sp aqueous extracts exhibited synergistic anti-plaque activity, and could be used as a useful active agent to produce oral health care products.

    Matched MeSH terms: Bacterial Adhesion/drug effects
  4. Analysis of biofilms formation by cronobacter sp. During growth in infant formula milk
    Aishah Faiqah Mohd Yusof, Prabhakaran P, Nur Diyana Azli, Norrakiah Abdullah Sani, Wan Syaidatul Aqma
    Sains Malaysiana, 2017;46:903-908.
    Pacifier nipples are in permanent contact with saliva and with the oral microflora therefore, act as a favoured site for the growth of biofilms. This research was conducted to identify the bacterial biofilms that has been found on the pacifiers that collected from local child nursery and to analyse the formation of biofilms by Cronobacter sp. during growth in infant formula milk. Pacifiers collected were analysed to obtain colony forming unit (CFU) and isolated bacteria were identified using several biochemical tests according to Bergey's Manual. Biofilm assay of three Cronobacter sp. were conducted using 24 wells microtiter plate and stained with 1% of crystal violet solution at different time interval: 6, 12, 18 and 24 h. The hydrophobicity of the bacterial cell suspension was evaluated using bacterial adhesion to hydrocarbons (BATH) method. Extracellular polymeric substances (EPS) analysis was done to identify percentage of carbohydrate and protein content by using phenol sulphuric acid method and Bradford method, respectively. The results obtained showed that the normal microflora bacteria were the most abundant microorganisms that were found on the pacifier with the main genus isolated was Staphylococcus sp., Enterobacteriaceae sp. and Clostridium sp. Based on biofilm and EPS analysis, Cronobacter sakazakii formed a strong biofilms after 18 h, with carbohydrate was identified as main component of EPS.
    Matched MeSH terms: Bacterial Adhesion
  5. In vitro study of Pasteurella multocida adhesion to trachea, lung and aorta of rabbits
    Al-Haddawi MH, Jasni S, Zamri-Saad M, Mutalib AR, Zulkifli I, Son R, et al.
    Vet J, 2000 May;159(3):274-81.
    PMID: 10775473
    In vitro experiments were undertaken to study the adhesion and colonization to tracheal mucosa, lung and aorta explants from freshly killed rabbits of two different strains of Pasteurella multocida. Serotype A:3 (capsulated, fimbriae +, haemagglutination -, dermonecrotic toxin -) isolated from a rabbit with rhinitis, and serotype D:1 (non-capsulated, fimbriae +, haemagglutination +, dermonecrotic toxin +) isolated from a dead rabbit with septicaemia, were used. When the explants were observed under the scanning electron microscope, the type D strain was highly adherent to trachea and aorta explants compared to the type A strain. Adhesion to lung explants was best achieved by the type A strain after 45 min incubation, but after 2 h incubation no significant difference was observed between the strains. Our data indicate that the presence of fimbriae and the absence of capsule seem to enhance the adherence of P. multocida type D strain to tracheal tissue. The capsular material of P. multocida type A strain and the toxin of the type D strain seem to influence the adherence to lung tissue in rabbit. Adhesion of strain D to aorta may indicate the expression of receptors on the endothelium to that strain and may also explain the ability of certain strains to cause septicaemia.
    Matched MeSH terms: Bacterial Adhesion*
  6. Enhanced intracellular survival and epithelial cell adherence abilities of Burkholderia pseudomallei morphotypes are dependent on differential expression of virulence-associated proteins during mid-logarithmic growth phase
    Al-Maleki AR, Mariappan V, Vellasamy KM, Shankar EM, Tay ST, Vadivelu J
    J Proteomics, 2014 Jun 25;106:205-20.
    PMID: 24742602 DOI: 10.1016/j.jprot.2014.04.005
    Colony morphology variation is a characteristic of Burkholderia pseudomallei primary clinical isolates, associated with variations in expression of virulence factors. Here, we performed comparative investigations on adhesion, invasion, plaque-forming abilities and protein profiles of B. pseudomallei wild-type (WT) and a small colony variant (SCV). The percentage of SCV adherence to A549 cells was significantly higher (2.73%) than WT (1.91%). In contrast, WT was significantly more efficient (0.63%) than SCV (0.31%) in invasiveness and in inducing cellular damage. Using 2-DE and MALDI TOF/TOF, 263 and 258 protein spots were detected in WT and SCV, respectively. Comparatively, 49 proteins were differentially expressed in SCV when compared with WT. Of these, 31 proteins were up-regulated, namely, nucleoside diphosphate kinase (Ndk), phosphoglycerate kinase (Pgk), thioredoxin (TrxA), putative ferritin DPS-family DNA-binding protein (DPS) and oxidoreductase (AhpC) that are known to be involved in adhesion, intracellular survival and persistence. However, among the 18 down-regulated proteins, enolase (Eno), elongation factor (EF-Tu) and universal stress-related proteins were associated with invasion and virulence. Differences observed in these protein profiles provide ample clues to their association with the morphotypic and phenotypic characteristics of colony variants, providing additional insights into the potential association of B. pseudomallei colony morphotypes with disease pathogenesis.
    Matched MeSH terms: Bacterial Adhesion
  7. The effect of the surface roughness of porcelain on the adhesion of oral Streptococcus mutans
    Al-Marzok MI, Al-Azzawi HJ
    J Contemp Dent Pract, 2009;10(6):E017-24.
    PMID: 20020077
    Dental plaque has a harmful influence on periodontal tissue. When a porcelain restoration is fabricated and refinishing of the glazed surface is inevitable, the increase in surface roughness facilitates the adhesion of plaque and its components. The aim of this in vitro study was to evaluate the effect of surface roughness of glazed or polished porcelain on the adhesion of oral Streptococcus mutans.
    Matched MeSH terms: Bacterial Adhesion/physiology*
  8. Quantitative PCR analysis of genes expressed during biofilm development of methicillin resistant Staphylococcus aureus (MRSA)
    Atshan SS, Shamsudin MN, Karunanidhi A, van Belkum A, Lung LT, Sekawi Z, et al.
    Infect Genet Evol, 2013 Aug;18:106-12.
    PMID: 23669446 DOI: 10.1016/j.meegid.2013.05.002
    Staphylococcus aureus biofilm associated infections remains a major clinical concern in patients with indwelling devices. Quantitative real-time PCR (qPCR) can be used to investigate the pathogenic role of such biofilms. We describe qPCRs for 12 adhesion and biofilm-related genes of four S. aureus isolates which were applied during in vitro biofilm development. An endogenous control (16S rRNA) was used for signal normalization. We compared the qPCR results with structural analysis using scanning electron microscopy (SEM). The SEM studies showed different cellular products surrounding the aggregated cells at different times of biofilm formation. Using qPCR, we found that expression levels of the gene encoding fibronectin binding protein A and B and clumping factor B (fnbA/B and clfB), which involves in primary adherence of S. aureus, were significantly increased at 24h and decreased slightly and variably at 48 h when all 4 isolates were considered. The elastin binding protein (ebps) RNA expression level was significantly enhanced more than 6-fold at 24 and 48 h compared to 12h. Similar results were obtained for the intercellular adhesion biofilm required genes type C (icaC). In addition, qPCR revealed a fluctuation in expression levels at different time points of biofilm growth of other genes, indicating that different parameter modes of growth processes are operating at different times.
    Matched MeSH terms: Bacterial Adhesion/genetics
  9. Fulltext Comparative characterisation of genotypically different clones of MRSA in the production of biofilms
    Atshan SS, Shamsudin MN, Lung LT, Sekawi Z, Ghaznavi-Rad E, Pei CP
    J Biomed Biotechnol, 2012;2012:417247.
    PMID: 22529705 DOI: 10.1155/2012/417247
    The ability to adhere and produce biofilms is characteristic of enhanced virulence among isolates of methicillin-resistant Staphylococcus aureus (MRSA). The aim of the study is to find out whether these characteristics are consistently similar among isolates variations of MRSA. The study used 30 various isolates of MRSA belong to 13 spa types and 5 MLST types and determined the aggregation, the adherence, and the production of biofilms and slime for each isolate. The methods used to evaluate these characteristics were a modified Congo red agar assay (MCRA), a microtiter plate assay (MPA), high-magnification light microscopy, scanning electron microscopy (SEM), and PCR. The study found that isolates belonging to similar Spa, SCCmec, and ST types have similar abilities to produce biofilms; however, their ability to produce slime on CRA was found to be different. Moreover, isolates that have different Spa types showed high variation in their ability to produce biofilms. The results of light microscope revealed the isolates that produced strong and weak biofilms and formed similar aggregation on the glass surfaces. SEM results showed that all 30 MRSA isolates that were tested were 100% positive for biofilm formation, although to varying degrees. Further testing using PCR confirmed that 100% of the 30 isolates tested were positive for the presence of the icaADBC, fnbA, eno, ebps, clfA, and clfB genes. The prevalence of fib, cna, fnbB, and bbp in MRSA clones was 90, 93.33, 53.33, and 10%, respectively. This study indicate that differences in biofilm production capacities are caused by the differences in surface protein A (Spa) type and are not due to differences in MLST and SCCmec types.
    Matched MeSH terms: Bacterial Adhesion/genetics
  10. Fulltext Molecular analysis of asymptomatic bacteriuria Escherichia coli strain VR50 reveals adaptation to the urinary tract by gene acquisition
    Beatson SA, Ben Zakour NL, Totsika M, Forde BM, Watts RE, Mabbett AN, et al.
    Infect Immun, 2015 May;83(5):1749-64.
    PMID: 25667270 DOI: 10.1128/IAI.02810-14
    Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli responsible for >80% of all cases. One extreme of UTI is asymptomatic bacteriuria (ABU), which occurs as an asymptomatic carrier state that resembles commensalism. To understand the evolution and molecular mechanisms that underpin ABU, the genome of the ABU E. coli strain VR50 was sequenced. Analysis of the complete genome indicated that it most resembles E. coli K-12, with the addition of a 94-kb genomic island (GI-VR50-pheV), eight prophages, and multiple plasmids. GI-VR50-pheV has a mosaic structure and contains genes encoding a number of UTI-associated virulence factors, namely, Afa (afimbrial adhesin), two autotransporter proteins (Ag43 and Sat), and aerobactin. We demonstrated that the presence of this island in VR50 confers its ability to colonize the murine bladder, as a VR50 mutant with GI-VR50-pheV deleted was attenuated in a mouse model of UTI in vivo. We established that Afa is the island-encoded factor responsible for this phenotype using two independent deletion (Afa operon and AfaE adhesin) mutants. E. coli VR50afa and VR50afaE displayed significantly decreased ability to adhere to human bladder epithelial cells. In the mouse model of UTI, VR50afa and VR50afaE displayed reduced bladder colonization compared to wild-type VR50, similar to the colonization level of the GI-VR50-pheV mutant. Our study suggests that E. coli VR50 is a commensal-like strain that has acquired fitness factors that facilitate colonization of the human bladder.
    Matched MeSH terms: Bacterial Adhesion
  11. Fulltext Stochasticity of bacterial attachment and its predictability by the extended derjaguin-landau-verwey-overbeek theory
    Chia TW, Nguyen VT, McMeekin T, Fegan N, Dykes GA
    Appl Environ Microbiol, 2011 Jun;77(11):3757-64.
    PMID: 21478319 DOI: 10.1128/AEM.01415-10
    Bacterial 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 two Salmonella enterica serovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each of S. enterica serovar Typhimurium, S. enterica serovar Infantis, or S. enterica serovar 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 each Salmonella serovar 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 containing S. Sofia S1296a for all different ratios were apparent for all materials. For S. 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.
    Matched MeSH terms: Bacterial Adhesion*
  12. Fulltext Anti-biofilm agents: recent breakthrough against multi-drug resistant Staphylococcus aureus
    Chung PY, Toh YS
    Pathog Dis, 2014 Apr;70(3):231-9.
    PMID: 24453168 DOI: 10.1111/2049-632X.12141
    Staphylococcus aureus is a Gram-positive pathogen that causes potentially life-threatening nosocomial- and community-acquired infections, such as osteomyelitis and endocarditis. Staphylococcus aureus has the ability to form multicellular, surface-adherent communities called biofilms, which enables it to survive in various sources of stress, including antibiotics, nutrient limitations, heat shock, and immune responses. Biofilm-forming capacity is now recognized as an important virulence determinant in the development of staphylococcal device-related infections. In light of the projected increase in the numbers of elderly patients who will require semi-permanent indwelling medical devices such as artificial knees and hips, we can anticipate an expanded need for new agents and treatment options to manage biofilm-associated infections in an expanding at-risk population. With better understanding of staphylococcal biofilm formation and growth, novel strategies that target biofilm-associated infections caused by S. aureus have recently been described and seem promising as future anti-biofilm therapies.
    Matched MeSH terms: Bacterial Adhesion/drug effects
  13. Fulltext Methicillin-Resistant Staphylococcus aureus Biofilms and Their Influence on Bacterial Adhesion and Cohesion
    Dakheel KH, Abdul Rahim R, Neela VK, Al-Obaidi JR, Hun TG, Yusoff K
    Biomed Res Int, 2016;2016:4708425.
    PMID: 28078291 DOI: 10.1155/2016/4708425
    Twenty-five methicillin-resistant Staphylococcus aureus (MRSA) isolates were characterized by staphylococcal protein A gene typing and the ability to form biofilms. The presence of exopolysaccharides, proteins, and extracellular DNA and RNA in biofilms was assessed by a dispersal assay. In addition, cell adhesion to surfaces and cell cohesion were evaluated using the packed-bead method and mechanical disruption, respectively. The predominant genotype was spa type t127 (22 out of 25 isolates); the majority of isolates were categorized as moderate biofilm producers. Twelve isolates displayed PIA-independent biofilm formation, while the remaining 13 isolates were PIA-dependent. Both groups showed strong dispersal in response to RNase and DNase digestion followed by proteinase K treatment. PIA-dependent biofilms showed variable dispersal after sodium metaperiodate treatment, whereas PIA-independent biofilms showed enhanced biofilm formation. There was no correlation between the extent of biofilm formation or biofilm components and the adhesion or cohesion abilities of the bacteria, but the efficiency of adherence to glass beads increased after biofilm depletion. In conclusion, nucleic acids and proteins formed the main components of the MRSA clone t127 biofilm matrix, and there seems to be an association between adhesion and cohesion in the biofilms tested.
    Matched MeSH terms: Bacterial Adhesion/drug effects*; Bacterial Adhesion/genetics
  14. Fulltext A quaternary ammonium silane antimicrobial triggers bacterial membrane and biofilm destruction
    Daood U, Matinlinna JP, Pichika MR, Mak KK, Nagendrababu V, Fawzy AS
    Sci Rep, 2020 07 03;10(1):10970.
    PMID: 32620785 DOI: 10.1038/s41598-020-67616-z
    To study the antimicrobial effects of quaternary ammonium silane (QAS) exposure on Streptococcus mutans and Lactobacillus acidophilus bacterial biofilms at different concentrations. Streptococcus mutans and Lactobacillus acidophilus biofilms were cultured on dentine disks, and incubated for bacterial adhesion for 3-days. Disks were treated with disinfectant (experimental QAS or control) and returned to culture for four days. Small-molecule drug discovery-suite was used to analyze QAS/Sortase-A active site. Cleavage of a synthetic fluorescent peptide substrate, was used to analyze inhibition of Sortase-A. Raman spectroscopy was performed and biofilms stained for confocal laser scanning microscopy (CLSM). Dentine disks that contained treated dual-species biofilms were examined using scanning electron microscopy (SEM). Analysis of DAPI within biofilms was performed using CLSM. Fatty acids in bacterial membranes were assessed with succinic-dehydrogenase assay along with time-kill assay. Sortase-A protein underwent conformational change due to QAS molecule during simulation, showing fluctuating alpha and beta strands. Spectroscopy revealed low carbohydrate intensities in 1% and 2% QAS. SEM images demonstrated absence of bacterial colonies after treatment. DAPI staining decreased with 1% QAS (p 
    Matched MeSH terms: Bacterial Adhesion/drug effects
  15. Fulltext Advancements in nano drug delivery systems: a challenge for biofilms in respiratory diseases
    Dua K, de Jesus Andreoli Pinto T, Chellappan DK, Gupta G, Bebawy M, Hansbro PM
    Panminerva Med, 2018 03;60(1):35-36.
    PMID: 29370678 DOI: 10.23736/S0031-0808.18.03402-X
    Matched MeSH terms: Bacterial Adhesion
  16. Calcium is required for ixotrophy of Aureispira sp. CCB-QB1
    Furusawa G, Hartzell PL, Navaratnam V
    Microbiology (Reading), 2015 Oct;161(10):1933-1941.
    PMID: 26306656 DOI: 10.1099/mic.0.000158
    Ixotrophy is a process that enables certain microbes to prey on other cells. The ability of cells to aggregate or adhere is thought to be a significant initial step in ixotrophy. The gliding, multicellular filamentous bacterium Aureispira sp. CCB-QB1 belongs to the family Saprospiraceae and preys on bacteria such as Vibrio sp. in seawater. Adhesion and cell aggregation were coincident with preying and were hypothesized to play an important role in the ixotrophy in this bacterium. To test this hypothesis, experiments to elucidate the mechanisms of aggregation or adhesion in this bacterium were performed. The ability of Aureispira QB1 to adhere and aggregate to prey bacterium, Vibrio sp., required divalent cations, especially calcium ions. In the presence of calcium, Aureispira QB1 cells captured 99 % of Vibrio sp. cells after 60 min of incubation. Toluidine blue O, which binds acidic polysaccharides, bound to Aureispira QB1 and inhibited adhesion of Aureispira QB1. These results suggest that acidic polysaccharides are needed for aggregation or adhesion of Aureispira and that calcium ions play a significant role in these phenomena.
    Matched MeSH terms: Bacterial Adhesion*
  17. Escherichia coli strains expressing H12 antigens demonstrate an increased ability to attach to abiotic surfaces as compared with E. coli strains expressing H7 antigens
    Goulter RM, Taran E, Gentle IR, Gobius KS, Dykes GA
    Colloids Surf B Biointerfaces, 2014 Jul 1;119:90-8.
    PMID: 24880987 DOI: 10.1016/j.colsurfb.2014.04.003
    The role of Escherichia coli H antigens in hydrophobicity and attachment to glass, Teflon and stainless steel (SS) surfaces was investigated through construction of fliC knockout mutants in E. coli O157:H7, O1:H7 and O157:H12. Loss of FliC(H12) in E. coli O157:H12 decreased attachment to glass, Teflon and stainless steel surfaces (p<0.05). Complementing E. coli O157:H12 ΔfliC(H12) with cloned wildtype (wt) fliC(H12) restored attachment to wt levels. The loss of FliCH7 in E. coli O157:H7 and O1:H7 did not always alter attachment (p>0.05), but complementation with cloned fliC(H12), as opposed to cloned fliCH7, significantly increased attachment for both strains compared with wt counterparts (p<0.05). Hydrophobicity determined using bacterial adherence to hydrocarbons and contact angle measurements differed with fliC expression but was not correlated to the attachment to materials included in this study. Purified FliC was used to functionalise silicone nitride atomic force microscopy probes, which were used to measure adhesion forces between FliC and substrates. Although no significant difference in adhesion force was observed between FliC(H12) and FliCH7 probes, differences in force curves suggest different mechanism of attachment for FliC(H12) compared with FliCH7. These results indicate that E. coli strains expressing flagellar H12 antigens have an increased ability to attach to certain abiotic surfaces compared with E. coli strains expressing H7 antigens.
    Matched MeSH terms: Bacterial Adhesion/genetics*
  18. Fulltext Production of Lipopeptide Biosurfactant by a Hydrocarbon-Degrading Antarctic Rhodococcus
    Habib S, Ahmad SA, Wan Johari WL, Abd Shukor MY, Alias SA, Smykla J, et al.
    Int J Mol Sci, 2020 Aug 26;21(17).
    PMID: 32858859 DOI: 10.3390/ijms21176138
    Rhodococci are renowned for their great metabolic repertoire partly because of their numerous putative pathways for large number of specialized metabolites such as biosurfactant. Screening and genome-based assessment for the capacity to produce surface-active molecules was conducted on Rhodococcus sp. ADL36, a diesel-degrading Antarctic bacterium. The strain showed a positive bacterial adhesion to hydrocarbon (BATH) assay, drop collapse test, oil displacement activity, microplate assay, maximal emulsification index at 45% and ability to reduce water surface tension to < 30 mN/m. The evaluation of the cell-free supernatant demonstrated its high stability across the temperature, pH and salinity gradient although no correlation was found between the surface and emulsification activity. Based on the positive relationship between the assessment of macromolecules content and infrared analysis, the extracted biosurfactant synthesized was classified as a lipopeptide. Prediction of the secondary metabolites in the non-ribosomal peptide synthetase (NRPS) clusters suggested the likelihood of the surface-active lipopeptide production in the strain's genomic data. This is the third report of surface-active lipopeptide producers from this phylotype and the first from the polar region. The lipopeptide synthesized by ADL36 has the prospect to be an Antarctic remediation tool while furnishing a distinctive natural product for biotechnological application and research.
    Matched MeSH terms: Bacterial Adhesion
  19. Fulltext Effect of rhamnolipid on the physicochemical properties and interaction of bacteria and fungi
    Hamzah N, Kasmuri N, Tao W, Singhal N, Padhye L, Swift S
    Braz J Microbiol, 2020 Sep;51(3):1317-1326.
    PMID: 32399689 DOI: 10.1007/s42770-020-00295-0
    Bacterial adhesion on surfaces is an essential initial step in promoting bacterial mobilization for soil bioremediation process. Modification of the cell surface is required to improve the adhesion of bacteria. The modification of physicochemical properties by rhamnolipid to Pseudomonas putida KT2442, Rhodococcus erythropolis 3586 and Aspergillus brasiliensis ATCC 16404 strains was analysed using contact angle measurements. The surface energy and total free energy of adhesion were calculated to predict the adhesion of both bacteria strains on the A. brasiliensis surface. The study of bacterial adhesion was carried out to evaluate experimental value with the theoretical results. Bacteria and fungi physicochemical properties were modified significantly when treated with rhamnolipid. The adhesion rate of P. putida improved by 16% with the addition of rhamnolipid (below 1 CMC), while the increase of rhamnolipid concentration beyond 1 CMC did not further enhance the bacterial adhesion. The addition of rhamnolipid did not affect the adhesion of R. erythropolis. A good relationship has been obtained in which water contact angle and surface energy of fungal surfaces are the major factors contributing to the bacterial adhesion. The adhesion is mainly driven by acid-base interaction. This finding provides insight to the role of physicochemical properties in controlling the bacterial adhesion on the fungal surface to enhance bacteria transport in soil bioremediation.
    Matched MeSH terms: Bacterial Adhesion/drug effects
  20. Probiotic and Safety Evaluation of Twelve Lactic Acid Bacteria as Future Probiotics
    Hu Y, Xie Y, Su Q, Fu J, Chen J, Liu Y
    Foodborne Pathog Dis, 2023 Nov;20(11):521-530.
    PMID: 37722019 DOI: 10.1089/fpd.2023.0039
    The human gut flora is highly diverse. Most lactic acid bacteria (LAB) are widely used as probiotics in human and animal husbandry and have a variety of physiological benefits. This article mainly studied the bacteriostatic ability of LAB against four pathogenic bacteria, gastrointestinal environment tolerance, and adhesion ability to Caco-2 cells. The genome of Lactiplantibacillus plantarum L461 was sequenced and analyzed. The results showed that strains F512, L461, and D469 had the most significant inhibitory effects on Escherichia coli, Salmonella enterica B, Staphylococcus aureus, and Listeria monocytogenes. In addition, strains L461, C502, and P231 showed good tolerance after exposure to simulated gastric fluid for 0-4 h. Strains C502, H781, and L461 showed good tolerance in simulated intestinal fluid. Strains L461 and H781 showed good adhesion to Caco-2 cells. The number of viable bacteria was more than 60. Therefore, we screened L. plantarum L461 from 12 LAB strains through three aspects of evaluation, and conducted whole genome sequencing and analysis. Sequencing results showed that L. plantarum L461 had more defense mechanisms and phage annotation genes than L. plantarum WCFS1. Virulence factor studies showed that L. plantarum L461 has iron absorption system and adhesion-related gene annotation, indicating that L. plantarum L461 has survival advantage in intestinal tract. The predicted results showed that there were eight phages with phage resistance in L. plantarum L461. L. plantarum L461 is sensitive to several antibiotics, notably penicillin and oxacillin. In summary, the results of this study prove that L. plantarum L461 has good prebiotic function and is safe. Therefore, L. plantarum L461 can be safely used as a potential functional probiotic.
    Matched MeSH terms: Bacterial Adhesion
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