Modeling the effect of pH, water activity, and ethanol concentration on biofilm formation of <i>Staphylococcus aureus</i>

Tango, Charles Nkufi,Akkermans, Simen,Hussain, Mohammad Shakhawat,Khan, Imran,Van Impe, Jan,Jin, Yong-Guo,Oh, Deog Hwan Elsevier 2018 Food microbiology Vol.76 No.-

<P><B>Abstract</B></P> <P>In this work, the effect of environmental factors on <I>Staphylococcus aureus</I> (ATCC 13150) biofilm formation in tryptic soy broth was investigated under different ranges of pH (3.0–9.5), ethanol concentration (EtOH 0.0–20.0%), and a<SUB>w</SUB> (NaCl, 0.866–0.992). Biofilm formation was quantified using the crystal violet staining method and optical density (OD: 590 nm) measurements. Biofilm formation was significantly stronger at pH and a<SUB>w</SUB> close to <I>S. aureus</I> optimal growth conditions, while it was high at EtOH around 2.5–3.5%. Data sets from the difference between the OD measurements of the test and control (ΔOD) were fitted to the cardinal parameter model (CPM) and cardinal parameter model with inflection (CPMI) to describe the effect of the environmental factors. The models showed good quality of fit for the experimental data in terms of calculated RMSE, with the latter ranging from 0.276 to 0.455. CPM gave a good quality of fit compared to CPMI for the environmental factors tested. Optimal pH was close to neutral (6.76–6.81) and biofilm formation was possible till pH = 3.81–3.78 for CPM and CPMI, respectively. Optimum EtOH and a<SUB>w</SUB> conditions for biofilm formation were in the range of 1.99–2.75 and 0.98–0.97, respectively. Predicted OD values observed using strain 13150 were very closely correlated to the OD values predicted with strain 12600 with R<SUP>2</SUP> of 0.978, 0.991, and 0.947 for pH, EtOH, and a<SUB>w</SUB>, respectively. The cultivable bacterial cells within the biofilm were enumerated using standard plate counting and a linear model was applied to correlate the attached biofilm cells to ΔOD of biofilm formation. It was found that the biofilm formation correlated with <I>S. aureus</I> population growth. At 2.5–3.5% of EtOH the maximum population density was lower than that observed at 0.0% of EtOH. As 2.5–3.5% of EtOH initiated a stronger biofilm formation, biofilm formation seems to be induced by ethanol stress. The development of cardinal parameter models to describe the effect environmental factors of importance to biofilm formation, offers a promising predictive microbiology approach to decrypting the <I>S. aureus</I> population growth and survival ability on food processing surfaces.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biofilm formation was significantly stronger at pH and aw close <I>S. aureus</I> growth optimal conditions. </LI> <LI> Biofilm formation was significantly high at ethanol concentration around 2.5–3.5%. </LI> <LI> CPM showed a better quality of fit compare to CPMI whatever the environmental factors. </LI> <LI> High extracellular matrix production depend on stress induced by ethanol at non-lethal concentrations. </LI> </UL> </P>

Substratum attachment location and biofilm formation by <i>Bacillus cereus</i> strains isolated from different sources: Effect on total biomass production and sporulation in different growth conditions

Hussain, Mohammad Shakhawat,Oh, Deog Hwan Elsevier 2017 Food control Vol.77 No.-

<P>Bacillus cereus, an endospore forming human pathogen associated With foodborne diseases, can form biofilms and attach to surfaces of processing equipment in the food industry. It is a consistent source of contamination and/or cross contamination of processed food products. The objective of this study was to understand substratum attachment location and biofilm formation behavior of B. cereus strains under different growth conditions. A total of 60 strains isolated from food, human, or farm and a number of reference strains were used in this study. Substratum attachment locations of these strains in 96-well microtiter plates were highly diversified among these strains. Strains isolated from food showed higher preference to attach at the air-liquid interface during early stage of biofilm formation. To the best of our knowledge, this is the first report showing the level of substratum attachment location and biofilm formation of B. cereus strains isolated from different sources. Substratum properties did not affect biofilm formation location when a number of selected strains were grown on stainless steel coupon, indicating that biofilm formation location might be independent of the type of substratum. Substratum attachment location and biofilm formation related phenotypes such as total biomass production, number of sessile cells, and sporulation were closely correlated. Substratum attachment location and sporulation behavior were strongly affected during biofilm formation under nutrient stress condition. The number of spores was significantly increased in biofilms grown under nutrient stress condition even though total biomass formation was lower. Our results on substratum attachment location and related biofilm formation behavior are substantially important for food industries where different surfaces are prone to B. cereus attachment, particularly for setting up and implementing clean in place (CIP) protocols. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Impact of the Isolation Source on the Biofilm Formation Characteristics of Bacillus cereus

( Mohammad Shakhawat Hussain ),( Deog-hwan Oh ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1

The human pathogen and food spoiler Bacillus cereus can form biofilms that act as a persistent source of contamination, which is of public health concern. This study aimed to understand how the source of isolation might affect the behavior of biofilm formation. Biofilm formation abilities of 56 strains of B. cereus isolated from different environments, including human food poisoning, farm, and food, were determined. Crystal violet assay results revealed significant (p < 0.05) differences in biofilm formation abilities among the strains isolated from different sources only at an early stage of incubation. However, strain origin showed no impact on later stage of biofilm formation. Next, correlation of the group of isolates on the basis of their biofilm-forming abilities with the number of sessile cells, sporulation, and extracellular polymeric substance (EPS) formation was determined. The number of sessile cells and spores in biofilms was greatly influenced by the groups of isolates that formed dense, moderate, and weak biofilms. The contribution of extracellular DNA and/or proteins to EPS formation was also positively correlated with biofilm formation abilities. Our results that the source of isolation had significant impact on biofilm formation might provide important information to develop strategies to control B. cereus biofilm formation.

<i>Lactobacillus plantarum</i> Lipoteichoic Acid Inhibits Oral Multispecies Biofilm

Kim, A Reum,Ahn, Ki Bum,Yun, Cheol-Heui,Park, Ok-Jin,Perinpanayagam, Hiran,Yoo, Yeon-Jee,Kum, Kee-Yeon,Han, Seung Hyun Elsevier 2019 JOURNAL OF ENDODONTICS - Vol.45 No.3

<P><B>Abstract</B></P> <P><B>Introduction</B></P> <P>Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether <I>Lactobacillus plantarum</I> lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.</P> <P><B>Methods</B></P> <P>Highly pure and structurally intact Lp.LTA was purified from <I>L. plantarum</I>. <I>Actinomyces naeslundii</I>, <I>Lactobacillus salivarius</I>, <I>Streptococcus mutans</I>, and <I>Enterococcus faecalis</I> were co-cultured to form oral multispecies biofilm in the presence or absence of Lp.LTA on culture plates or human dentin slices. Preformed biofilm was treated with or without Lp.LTA, followed by additional treatment with intracanal medicaments such as calcium hydroxide or chlorhexidine digluconate. Confocal microscopy and crystal violet assay were performed to determine biofilm formation. Biofilm on human dentin slices was visualized with a scanning electron microscope.</P> <P><B>Results</B></P> <P>Biofilm formation of multispecies bacteria on the culture dishes was dose-dependently reduced by Lp.LTA compared with the nontreatment control group. Lp.LTA also inhibited multispecies biofilm formation on the dentin slices in a dose-dependent manner. Interestingly, Lp.LTA was shown to reduce preformed multispecies biofilm compared with the nontreatment group. Moreover, Lp.LTA potentiated the effectiveness of the intracanal medicaments in the removal of preformed multispecies biofilm.</P> <P><B>Conclusions</B></P> <P>These results suggest that Lp.LTA is a potential anti-biofilm agent for treatment or prevention of oral infectious disease, including apical periodontitis, which is mainly caused by multispecies bacterial biofilm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Lactobacillus plantarum</I> lipoteichoic acid (Lp.LTA) inhibits oral multispecies biofilm formation. </LI> <LI> Lp.LTA disrupts preformed multispecies biofilm. </LI> <LI> Lp.LTA and intracanal medicaments cooperatively reduce the preformed biofilm. </LI> <LI> Lp.LTA could be used for endodontic treatment against biofilm-associated diseases including apical periodontitis. </LI> </UL> </P>

The effects of orthodontic bonding steps on biofilm formation of <i>Streptococcus mutans</i> in the presence of saliva

Ahn, Sug-Joon,Cho, Eun-Jung,Oh, Sung-Suk,Lim, Bum-Soon Informa Healthcare 2012 Acta odontologica scandinavica Vol.70 No.6

<P><B><I>Objective.</I></B> To investigate the effects of various orthodontic bonding steps on biofilm formation of <I>Streptococcus mutans</I> in the presence of saliva. <B><I>Materials and methods:</I></B> Hydroxyapatite (HA) and orthodontic adhesive (AD) disks were prepared to a uniform size. HA disks were etched with 37% phosphoric acid gel in the etched group (HE). In the primed group (HP), Transbond XT primer was applied to the etched HA surface and light-cured. For biofilm formation, <I>Streptococcus mutans</I> was grown on each specimen in a biofilm medium with either glucose or sucrose in the presence of fluid-phase UWS (F-UWS) or surface adsorbed saliva (S-UWS). The adherent bacteria were quantified by enumeration of the total viable counts of bacteria. Biofilms formed on each surface were examined by scanning electron microscopy. <B><I>Results.</I></B> When glucose was used, both F-UWS and S-UWS suppressed biofilm formation of <I>S. mutans.</I> Compared to HA and HE, biofilm formation was significantly inhibited on HP and AD in the presence of glucose. Biofilm-forming patterns that were inhibited by saliva were restored in a sucrose-containing medium. F-UWS promoted biofilm formation on HA and HE, while S-UWS significantly promoted biofilm formation on HP. <I>S. mutans</I> developed biofilm better on HA and HE than on AD when sucrose was used as the sole carbohydrate source. <B><I>Conclusions.</I></B> This study suggests that the biofilm development by <I>S. mutans</I> is significantly influenced by the orthodontic bonding procedure. Biofilm formation of <I>S. mutans</I> was inhibited on AD more than other surfaces, irrespective of the presence of saliva or a carbohydrate source.</P>

Anti-Biofilm Effect of Egg Yolk Phosvitin by Inhibition of Biomass Production and Adherence Activity against Streptococcus mutans

Hyeon Joong Kim,Jae Hoon Lee,Dong Uk Ahn,Hyun-Dong Paik 한국축산식품학회 2020 한국축산식품학회지 Vol.40 No.6

The formation of biofilms on the enamel surface of teeth by Streptococcus mutans is an important step in dental plaque formation, demineralization, and early caries because the biofilm is where other bacteria involved in dental caries attach, grow, and proliferate. The objectives of this study were to determine the effect of phosvitin (PSV) on the biofilm formation, exopolysaccharides (EPS) production, adherence activity of S. mutans, and the expression of genes related to the compounds essential for biofilm formation (quorum-sensing inducers and components of biofilm matrix) by S. mutans. PSV significantly reduced the biofilm-forming activity of S. mutans and increased the degradation of preformed biofilms by S. mutans. PSV inhibited the adherence activity of S. mutans by 31.9%-33.6%, and the production of EPS by 62%-65% depending upon the strains and the amount of PSV added. The expressions of genes regulating the production of EPS and the quorum-sensing-inducers (gtfA, gtfD, ftf, relA, vicR, brpA, and comDE) in all S. mutans strains were down-regulated by PSV, but gtfB was down-regulated only in S. mutans KCTC 5316. Therefore, the anti-biofilm-forming activity of PSV was accomplished through the inhibition of biofilm formation, adherence activity, and the production of quorum-sensing inducers and EPS by S. mutans.

Long-term anti-cariogenic biofilm activity of glass ionomers related to fluoride release

Chau, N.P.T.,Pandit, S.,Jung, J.E.,Cai, J.N.,Yi, H.K.,Jeon, J.G. Elsevier 2016 Journal of dentistry Vol.47 No.-

<P>Objectives: The aim of this study was to evaluate the difference between anti-cariogenic biofilm activities of glass ionomers (G-Is) during the initial and second fluoride release phases and to define relationships between the anti-biofilm activities and fluoride release. Methods: Fluoride release of three commercially available G-Is in a buffer was evaluated for 770 h, and then 70-h-old Streptococcus mutans UA159 biofilms were formed on the G-Is that had been immersed in the buffer for 0, 100, 200, or 700 h. The dry weight, bacterial cell number, water-insoluble extracellular polysaccharides (EPSs), and accumulated fluoride concentration of the 70-h-old biofilms and fluoride release and acid production rates during biofilm formation were determined. Relationships between the experimental variables and fluoride release rate were also evaluated using linear regression analysis. Results: In this study, fluoride release of the tested G-Is did not exhibit a biphasic pattern during biofilm formation. The release was sustained or did not rapidly decrease even over long immersion periods and was strongly correlated with an increase in accumulated fluoride concentration of the biofilms (R = 0.99, R-2 = 0.98) and reductions in dry weight, water-insoluble EPSs, and acid production rate of the biofilms (R = - 0.99 to - 0.96, R-2 = 0.92-0.98). Conclusions: This study suggests that G-Is can effectively affect acid production, EPS formation, and accumulation of cariogenic biofilms even during the second fluoride release phase, and that the anti-cariogenic biofilm activity is strongly correlated with fluoride release, which may be enhanced by acid production of cariogenic biofilms. (C) 2016 Elsevier Ltd. All rights reserved.</P>

녹농균의 생장과 생물막 형성에 미치는 전기와 전자기의 효과

김세진,신영선,박신해,임수진,황현지,김수경,이준희 한국미생물학회 2020 미생물학회지 Vol.56 No.3

Bacterial growth and biofilm formation mediate serious infections in human and cause many problems in civil and industrial facilities. In this study, electricity and magnetic field have been tested to modulate bacterial growth and biofilm formation. As model bacteria, a common model bacterium Escherichia coli, a human pathogen Pseudomonas aeruginosa that is a notorious biofilm-former, and a pus-forming pathogen Staphylococcus aureus were used. When direct current electricity was applied, there was no effect at 1.5 V, but bacterial growth was suppressed at 3 V, and growth was more strongly suppressed on the cathode side. To know the magnetic field effect on biofilm formation, while P. aeruginosa was forming biofilm in flow-cell system, magnetic field was given by magnet or solenoid wound around the flow-cell chamber. The magnitude of magnetic field was adjusted by changing the number of coils of the solenoid and other factors such as current and voltage were fixed. Our results obtained from the observation and quantification by confocal microscopy showed that the magnetic field’s effect on biofilm formation of P. aeruginosa varies depending on the magnitude of the field. Although strong magnetic fields might inhibit biofilm formation, our results showed that biofilm formation increased when a weak magnetic field is given. 세균의 생장과 생물막 형성은 인체 내에서 심각한 감염을매개하며 여러 건축물 혹은 산업 시설에서 많은 문제를 야기한다. 본 연구에서는 전기 혹은 자기장이 세균의 생장과 생물막형성을 변화시킬 수 있는지 조사하였다. 세균 모델로는 일반적으로 많이 사용되는 대장균(Escherichia coli)과 생물막을 잘형성하는 병원성 세균인 녹농균(Pseudomonas aeruginosa), 그리고 화농성 세균인 황색포도상구균(Staphylococcus aureus) 이 사용되었다. 직류 전기를 대장균, 녹농균, 황색포도상구균에 인가하였을 때, 1.5 V에서는 영향이 없었으나, 3 V에서는생장이 억제되었으며, 특히 + 전극 쪽에서 생장이 더 강하게억제되었다. 생물막 형성에 미치는 자기장의 효과를 알기 위해, 녹농균이 flow-cell 내에서 생물막을 형성하는 동안 자석또는 flow-cell을 감은 솔레노이드를 통해 자기장을 부여하였다. 자기장의 크기는 솔레노이드의 코일 수를 변화시킴에 의해 조절되었으며, 전류 및 전압과 같은 다른 요소는 일정하게고정되었다. 생물막 형성을 공초점 현미경으로 관찰 및 정량한 결과는 녹농균의 생물막 형성에 대한 자기장의 영향이 크기에 따라 다르다는 것을 보여주었다. 강한 자기장이 녹농균생물막 형성을 억제할 수도 있었으나, 약한 자기장이 주어졌을 때는 오히려 생물막 형성이 증가함을 보여주었다.

Impact of Cranberry Juice and Proanthocyanidins on the Ability of Escherichia coli to Form Biofilms

Paola Andrea Pinzón-Arango,Kerrie Holguin,Terri Anne Camesano 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.5

The effects of cranberry juice cocktail (CJC)and proanthocyanidins (PACs) on biofilm formation were investigated. Escherichia coli strain HB101pDC1 and nonfimbriated strain HB101 were grown in 10 wt% CJC or 120 μg/mL PACs for 12 consecutive cultures. Biofilm formation was investigated by incubating bacteria in 96-well polyvinyl chloride (PVC) plates and studying the optical density of the solution using the crystal violet method. We suspect that biofilm formation occurred due to non-specific interactions between the bacteria and the polymer. Both P-fimbriated E. coli HB101pDC1 and the non-fimbriated strain HB101 formed biofilms. E. coli strain HB101pDC1 formed a thicker and more mature biofilm. Cranberry juice inhibited biofilm formation after the first culture; however, for bacteria grown in PACs, a decrease in biofilm formation was observed with increasing number of cultures. The inhibitory effect was reversible. These results demonstrate that CJC is more effective than isolated PACs at preventing biofilm formation, possibly suggesting that other cranberry compounds also play a role in anti-biofilm activity.

Diverse plant extracts and trans-resveratrol inhibit biofilm formation and swarming of Escherichia coli O157:H7

( Jin Hyung Lee ),( Hyun Scob Cho ),( Sang Woo Joo ),( Sushil Chandra Regmi ),( Jung Ae Kim ),( Choong Min Ryu ),( Shi Yong Ryu ),( Moo Hwan Cho ),( Jintae Lee ) 영남대학교 약품개발연구소 2014 영남대학교 약품개발연구소 연구업적집 Vol.24 No.0

Infection with enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem. Of the 498 plant extracts screened against EHEC, 16 inhibited the formation of biofilm of EHEC by >85% without inhibiting the growth of planktonic cells, and 14 plant extracts reduced the swarming motility of EHEC. The most active extract, Carex dimorpholepis, decreased swimming and swarming motilities and curli formation. Transcriptional analyses showed that the extract of C. dimorpholepis repressed curli genes, various motility genes, and AI-2 quorum sensing genes, which was corroborated by reduction in the production of fimbria, motility, and biofilm by EHEC. Trans-resveratrol at 10μgml(-1) in the extract of C. dimorpholepis was found to be a new anti-biofilm compound against EHEC, but importantly, the extract of C. dimorpholepis and trans-resveratrol did not inhibit the fomation of biofilm in four commensal E. coli strains. Furthermore, the extract of C. dimorpholepis decreased the adhesion of EHEC cells to human epithelial cells without affecting the viability of these cells.