Thesis (Ph. D.)--University of Iowa, 2007. / Thesis supervisor: Gene F. Parkin. Includes bibliographical references (leaves 156-163).

Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Anne Camper. Includes bibliographical references (leaves 109-125).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed May 23, 2007). PDF text: 135 p. : ill. (some col.) ; 1.57Mb UMI publication number: AAT 3237385. Includes bibliographical references. Also available in microfilm and microfiche formats.

Floating sulphur biofilms are observed as surface layers in numerous aquatic sulphide-rich environments, and apparently play an important role in the cycling of sulphur in its various oxidation states. In addition to the conversion of sulphide to sulphur and/or sulphate species, it has been suspected that subsequent reduction back to sulphide may occur within the floating sulphur biofi1m in organic-rich environments. The use of sulphur biofilms for the harvesting of elemental sulphur from wastewater treatment systems has also been suggested. There is, however, little documented information in the literature on the structure of floating sulphur biofilms, or the microbial species responsible for their occurrence. In this study, floating sulphur biofilms were generated in a continuous flow baflle reactor and their structure was examined using scanning electron microscopy. It was found that they occur as layered structures with morphologically distinct bacterial forms present in different layers of the biofilm. The biofilpl structure was also found to be dynamic, with structural changes observed as feed conditions were altered. An enriched culture derived from the biofi1m demonstrated rates of sulphide oxidation comparable to values reported in the literature for liquid culture systems. The microbiology of the biofi1m was studied using traditional plate culture techniques and analysis ofrRNA genes. Identification of plate culture isolates as representatives of the biofi1m community proved to be limited, leading to a PeR-based cloning approach. The majority of the organisms present in the sulphur biofi1m were classified as species in the genus ~eudomonas, and a number of other bacterial species whose sulphide oxidising capacity has been noted previously. Surprisingly, only 2% of the clone library consisted of Thiobacillus spp., and no sulphate reducing bacteria were identified in the biofilm at all. These results indicate that in organic sulphide-rich environments facultative chemolithoheterotrophic bacterial forms predominate in floating sulphur biofilms, and that the complete biological cycling of sulphur may not occur in these systems.

A number of methods are currently in use for attenuating nitrates from wastewater with varying degrees of efficiency. Bioremediation using bacteria may be an efficient and cost effective method. In an anaerobic bioremediation system, nitrate can replace carbon dioxide as an electron acceptor and aids in nitrate attenuation by assimilatory reduction. The purpose of this study was to investigate nitrate attenuation in a hyperfiltration system using a pure culture of strictly anaerobic, facultative Methanobrevibacter ruminantium bacteria. Filtration experiments were conducted using amalgamated Na- montmorillonite clay-glass beads compacted at 500 psi differential hydraulic pressure with or without a biofilm. A simulated agricultural wastewater of 3.105?10-4 moles/L of NO3- was bioremediated. The use of bacteria in attenuating nitrates offers promising results on a bench-scale.

The yeast Candida is an opportunistic human pathogen often associated with nosocomial infections. Understanding of the fungal virulence factor is limited. Adhesion and biofilm formation on prosthetic devices is likely to be one such factor for Candida infection. Biofilms form a structured community embedded by exopolymeric substances. Catheter associated Candidiasis is problematic since biofilm is hard to eradicate by antifungal therapy alone. / C. parapsilosis is a normal human commensal commonly isolated from human skin. C. parapsilosis is considered to be an emerging fungal pathogen and particularly associated with infections in neonates and catheterized intensive care unit (ICU) patients. Thus investigating the characteristics of biofilm formation helps to understand the biology of C. parapsilosis biofilm and assess the prognosis of the infection. / Also, we still only know a little about the mechanisms of biofilm formation in C. parapsilosis. Genetic studies about C. parapsilosis biofilm, especially in clinical samples are rare. Agglutinnin-like sequence (ALS) genes are commonly studied and well known in C. albicans but not in C. parapsilosis. Recently, some bioinformatics studies had revealed the presence of five ALS genes in C. parapsilosis. Some differentially expressed genes in C. parapsilosis biofilm were also identified in other studies. In this study, our aim is to investigate the characteristics of the clinical isolates of C. parapsilosis and the expressions of the selected genes in the biofilm. / In this study, the demographic characteristics of 61 patients with C. parapsilosis fungemia were studied. Among the patients, 60.6% aged higher than 65 years old. The risk factors of previous antibiotic treatment and venous catheterization were both towered in 72.13% of the patients. No resistant C. parapsilosis against amphotericin B and fluconazole was isolated in the studied samples. A static biofilm formation model was designed to investigate the biofilm formation of the samples using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetra zolium hydroxide (XTT) assay. Quantitative real-time PCR was carried out to evaluate the temporal expression five ALS gene and one ERG11 gene in the biofilm of the clinical samples. The differential expression of the five ALS genes and ERG11 gene of the high biofilm forming group and low biofilm forming group of the clinical samples were compared. Our result shows that CPAG_05056 and CPAG_00369 were relatively more expressed in the high biofilm forming group and was upregulated at 24 h. CPAG_05314 was relatively more expressed in the high biofilm forming group and was more upregulated at 1.5h. The expression of CPAG_05054 was relatively higher in high biofilm forming group but showed similar expression level at 1.5 h and 24 h for both groups of samples. CPAG_00368 and ERG11 expression was relatively higher in low biofilm forming group and downregulated at 1.5 h and 24 h for both groups of samples. / In conclusion, C. parapsilosis bloodstream infection was prevalence in the elderly. Patients with prolonged hospital stay, being in the ICU, received antibiotic treatments and venous catheter are at a very high risk of infection. The ability to form biofilm in C. parapsilosis showed great variations among the clinical samples tested in our static biofilm formation model. The expression of CPAG_05056, and CPAG_00369 may be involved in the late stage of biofilm formation by C. parapsilosis. Expression of CPAG_05314 is believed to be involved in the early stage of biofilm formation. The expression of CPAG_05054 may be involved in both early and late stage of biofilm formation. CPAG_00368 and ERG11 were downregulated and seemed to show no relation to biofilm formation to both groups in our tested model. The result indicated that these genes may only be partly responsible for biofilm formation. The mechanisms of biofilm formation in C. parapsilosis is far more complicated. / 念珠菌是一種機會性人類病原體，並經常與院內感染有關。現時對於真菌致病因子的了解是有限的。而粘附在人工物質上的和形成生物膜的特性可能是一個念珠菌感染的因素。生物膜形成一個被外在聚合體包圍的結構化的群落。而導管相關性念珠菌引發血流感染是有其存在的問題，因為單靠抗真菌治療是很難根除生物膜。 / 近平滑念珠菌是一種正常的人類定植真菌並分佈於人體皮膚表面。近平滑念珠菌被認為是一個新興的病原真菌，特別是感染嬰兒和有插管的深切治療病房病人。因此，調查生物膜形成的特點能有助於理解近平滑念珠菌生物膜的生物學和有效預防感染。 / 此外，研究人員仍然對近平滑念珠菌生物膜形成的機制了解甚少。而關於近平滑念珠菌生物膜的基因研究，尤其是對其臨床標本研究的是很罕見的。類凝集素基因(ALS)基因的研究目前集中在於白色念珠菌，但不是在近平滑念珠菌。最近，在一些生物信息學研究中揭示了ALS基因亦存在於近平滑念珠菌。而其他在近平滑念珠菌生物膜中差異表達的基因在其他研究中也被確定。本研究的目的是調查近平滑念珠菌的臨床標本的特性和所選擇的基因在臨床標本所形成的生物膜中的表達。 / 在這項研究中，對61個近平滑念珠菌血液感染患者的人口學特徵進行了研究。而其中60.6％的病人年齡高於65歲。原有的抗生素治療，靜脈置管的危險因素則有72.13％的患者伴有。在所研究的臨床樣品中無發現對兩性黴素B和氟康唑有抗性的近平滑念珠菌。利用靜態生物膜形成模型和使用XTT法來檢測臨床標本的生物膜形成。進行了定量實時聚合酶鏈反應來評測五個ALS基因和ERG11基因在臨床樣品的生物膜形成中的時間性表達。五個ALS基因和ERG11基因在高生物膜形成組和低生物膜的形成組的臨床樣本中的差異表達進行了比較。我們的結果表明，CPAG_05056基因和CPAG_00369基因相對更表現在高生物膜成形組，並在二十四小時的時間點上調。CPAG_05314基因相對在高生物膜形成組表達並在一小時半的時間點上調。高生物膜形成組的CPAG_05054基因表達較高，但在一小時半和二十四小時都表現出相似的表達水平。CPAG_00368基因和ERG11基因表達相對在低生物膜形成組較高，而兩組樣品的表達都一小時半和二十四小時下調。 / 本次研究得出的結論是，近平滑念珠菌血流感染在中老年人的患病率較高。長期住院的患者，在深切治療病房，接受抗生素治療和有靜脈插管都會提高感染風險。在測試所用的靜態生物膜形成模型中，近平滑念珠菌臨床樣本之間的生物膜形表現出不同的變化。而的CPAG_05056基因和CPAG_00369基因的表達可能和近平滑念珠菌生物膜形成的後期有關。CPAG_05314基因表達被認為是涉及生物膜形成的早期階段。CPAG_05054基因表達可能涉及生物膜形成的早期和後級。在本次測試模型中，CPAG_00368和ERG11的基因表達在兩個組別下調，可能與生物膜形成沒有直接關係。以上證明所研究的基因可能只涉及生物膜形成過程的一部份而近平滑念珠菌的生物膜形成應更為複雜。 / Man, Wing Chung. / Thesis M.Phil. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 91-102). / Abstracts also in Chinese. / Title from PDF title page (viewed on 24, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

This thesis embodies research investigating the role that bacterial biofilms play in the pathogenesis of chronic rhinosinusitis (CRS). It focuses on their detection on the sinus mucosa of CRS patients and the implications of their presence. Finally, it addresses deficiencies in the innate immune system that may predispose to their development in this condition. Bacterial biofilms are structural assemblages of microbial cells that encase themselves in a protective self-produced matrix and irreversibly attach to a surface. Their extreme resistance to both the immune system as well as medical therapies has implicated them as playing a potential role in the pathogenesis of many chronic diseases. Although their role in many diseases is now well established, their objective presence and importance in CRS remains largely unknown. Chapter 1 of this thesis reviews the current literature pertaining to CRS and biofilms and critically evaluates the small body of research relating to this topic. Chapter 2 describes the development of a sheep model to study the role of bacterial biofilms in rhinosinusitis. It compares the use of traditional electron microscopy (EM) and more recent confocal scanning laser microscopy (CSLM) in the detection of biofilms on the surface of sinus mucosa. The results of this study inferred a causal relationship between biofilms and the macroscopic changes that accompany rhinosinusitis. Furthermore it illustrated the superiority that CSLM has over EM in the imaging of biofilms on sinus mucosa Chapter 3 and 4 outline the results of human studies utilizing the more objective CSLM to evaluate the prevalence of bacterial biofilms on the sinus mucosa of CRS patients and their effect on post-operative mucosal healing. The results of these studies demonstrated a biofilm prevalence of approximately 50% in the CRS population studied and suggested, that biofilm presence may predispose to adverse post-operative outcomes following sinus surgery. Chapter 5 and 6 describe experiments examining the level of the innate immune system’s anti-biofilm peptide lactoferrin, in patients with CRS. Lactoferrin was found to be downregulated at both an mRNA and protein level in the majority of CRS patients, with biofilm positive patients demonstrating the most significant reduction. In summary, this thesis provides further evidence that bacterial biofilms play a major role in the pathogenesis and disease persistence in a subset of CRS patients. Deficiencies in components of the innate immune system, such as lactoferrin, may play an important role in the predisposition of certain individuals to the initial development of bacterial biofilms. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1346621 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine 2008

This thesis embodies research investigating the role that bacterial biofilms play in the pathogenesis of chronic rhinosinusitis (CRS). It focuses on their detection on the sinus mucosa of CRS patients and the implications of their presence. Finally, it addresses deficiencies in the innate immune system that may predispose to their development in this condition. Bacterial biofilms are structural assemblages of microbial cells that encase themselves in a protective self-produced matrix and irreversibly attach to a surface. Their extreme resistance to both the immune system as well as medical therapies has implicated them as playing a potential role in the pathogenesis of many chronic diseases. Although their role in many diseases is now well established, their objective presence and importance in CRS remains largely unknown. Chapter 1 of this thesis reviews the current literature pertaining to CRS and biofilms and critically evaluates the small body of research relating to this topic. Chapter 2 describes the development of a sheep model to study the role of bacterial biofilms in rhinosinusitis. It compares the use of traditional electron microscopy (EM) and more recent confocal scanning laser microscopy (CSLM) in the detection of biofilms on the surface of sinus mucosa. The results of this study inferred a causal relationship between biofilms and the macroscopic changes that accompany rhinosinusitis. Furthermore it illustrated the superiority that CSLM has over EM in the imaging of biofilms on sinus mucosa Chapter 3 and 4 outline the results of human studies utilizing the more objective CSLM to evaluate the prevalence of bacterial biofilms on the sinus mucosa of CRS patients and their effect on post-operative mucosal healing. The results of these studies demonstrated a biofilm prevalence of approximately 50% in the CRS population studied and suggested, that biofilm presence may predispose to adverse post-operative outcomes following sinus surgery. Chapter 5 and 6 describe experiments examining the level of the innate immune system’s anti-biofilm peptide lactoferrin, in patients with CRS. Lactoferrin was found to be downregulated at both an mRNA and protein level in the majority of CRS patients, with biofilm positive patients demonstrating the most significant reduction. In summary, this thesis provides further evidence that bacterial biofilms play a major role in the pathogenesis and disease persistence in a subset of CRS patients. Deficiencies in components of the innate immune system, such as lactoferrin, may play an important role in the predisposition of certain individuals to the initial development of bacterial biofilms. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1346621 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine 2008

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Little is known about the impact of nutrient conditions on antimicrobial resistance in biofilms grown under continuous flow conditions. Furthermore, community-level response of biofilms to antimicrobial substances and different nutrient regimes are poorly described. A better understanding of the influence of environmental conditions on biofilm behavior and antimicrobial susceptibility may contribute to the efforts, addressing the problems associated with increased antimicrobial resistance. Therefore, the aim of this study was to evaluate the survival and population dynamics in a defined mixed-species biofilm community grown under different nutrient conditions and when subjected to biocide treatment. Epi-fluorescence microscopy in conjunction with the LIVE/DEAD® BacLight™ viability kit, a conventional cultivation technique (plate counts), and culture-independent techniques (terminal restriction fragment length polymorphism and fluorescent in situ hybridization) were applied to observe biofilm and planktonic antimicrobial susceptibility, as well as population dynamics. A defined mixed-species community, consisting of four bacterial strains, was cultivated and monitored in a flow cell system. Two nutrient types were used: 1) a complex growth medium [tryptone soy broth (TSB)] and 2) a defined synthetic medium [minimal salts supplemented with glucose (MSM + Glucose)]. In addition, these two nutrient types were applied in different concentrations. Biofilm and planktonic community behavior was influenced by the nutrient type and concentration. Species evenness in the planktonic community was influenced by the nutrient conditions, while species richness changed in response to biocide treatment and nutrient conditions. TSB-grown microbial communities were more susceptible directly after biocide treatment than those grown in MSM + Glucose, however, biofilm viability in the latter nutrient condition decreased within 24 h after biocide treatment. Furthermore, a surprising difference in the recovery rate between biofilm and associated planktonic communities was observed. A conceptual model was developed that aimed to explain the observed biofilm-planktonic interactions. This model proposes that the cells found in the outer regions of a biofilm are the primary source of the associated planktonic cells, and that this phenomenon is independent from overall biofilm activity. / AFRIKAANSE OPSOMMING: Daar IS tans mm bekend oor die invloed van nutriënte op die antirnikrobiese weerstandbiedendheid van biofilms onder kontinue vloeitoestande. Verder is daar 'n groot leemte in die literatuur oor die invloed van nutriënte op die antimikrobiese sensitiwiteit van bakteriese gemeenskappe in multispesie-biofilms. 'n Beter begrip van die invloed van omgewingsfaktore op biofilmgedrag en antimikrobiese sensitiwiteit sal bydra om die probleem van verhoogde antimikrobiese weerstandbiedendheid te beheer. Die doel van hierdie studie was gevolglik om die oorlewingsvermoë, asook die gemeenskapverskuiwings binne 'n bekende biofilmgemeenskap te evalueer, nadat dit blootgestel was aan biosiedbehandeling en verskillende nutriëntkondisies. Epifluoressensie-mikroskopie in kombinasie met 'n lewensvatbaarheidskleurstof (LIVEIDEAD® BacLight™ viability kit), konventioneie kweektegnieke (spreiplaattegniek) en kweekonafhanklike identifikasietegnieke (terminale restriksie fragment lengte polimorfisme en fluoressensie in situ hibridisasie) is gebruik om biofilm- en planktoniese lewensvatbaarheid, asook gemeenskapverskuiwings te bestudeer. 'n Gedefinieerde biofilmgemeenskap, bestaande uit vier verskillende bakteriese rasse, is gekweek en gemonitor in 'n vloeiselsisteem. Twee tipes nutriënte is gebruik: (1) 'n komplekse groeimedium [Tryptone Soy Broth (TSB)] en (2) 'n chemies-gedefinieerde medium [minimale soutoplossing met glukose (MSM + Glucose)]. Beide nutriënttipes is in verskillende konsentrasies toegedien. Die gedrag van biofilm- sowel as planktoniese populasies is beïnvloed deur beide die nutriënttipe en konsentrasie. Planktoniese populasiegetalle is beïnvloed deur nutriëntkondisies, terwyl die aantal populasies beïnvloed is deur biosiedbehandeling en nutriënttoestande. Bakteriese gemeenskappe wat in komplekse medium (TSB) gekweek is, was meer sensitief teenoor die biosied direk na behandeling as die wat in MSM + Glukose gekweek is. Die lewensvatbaarheid van die biofilm wat in MSM + Glukose gekweek is, het egter eers 24 uur na biosiedbehandeling begin daal. Daar was verder 'n opvallende verskil in die tempo van herstel van die biofilmgemeenskap in vergelyking met die planktoniese gemeenskap. Die planktoniese gemeenskap het vinniger herstel as die biofilm gemeenskap. 'n Model is ontwikkel om die biofilm-planktoniese interaksies te verklaar. In die model word voorgestel dat selle wat in die buitenste lae van 'n biofilm groei, die primêre bron is van planktoniese selle in 'n vloeisisteem, en dat hierdie verskynselonafhanklik is van die algehele biofilm-aktiwiteit.

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Complex biofilm communities have extensively been studied in the past. Less work has been done on the early stages of biofilm formation. This study aimed to assess initial colonization patterns of biofilms on different surfaces and under different environmental conditions with application of novel methods describing biofilm surface profiles. Biofilms were cultivated on glass, polyvinylchloride (PVC) and polished stainless steel. Results from microscopy, followed by mathematical analysis and contact angle measurements proved that glass was the most appropriate substrate for this study. More extensive extracellular polymeric substances (EPS) production and apparently less cell attachment were observed on PVC and polished stainless steel surfaces. Two different series of experiments were conducted where biofilms were cultivated on the glass. Biofilm morphology was analysed under various conditions of temperature and nutrient concentration. Different temperature conditions were 8°C, 22°C and 37°C and different nutrient concentrations were 0.1%, 1% and 10% Tryptic Soy Broth (TSB). After obtaining samples after 1, 2, 3 and 4 days respectively, the biofilm surfaces were visualised using atomic force microscopy (AFM) and epifluorescence microscopy. Less cell attachment was displayed at lower temperatures and nutrient limitations. The roughness profile of the early stages of biofilm development was explored by the novel application of various existing statistical methods. Benoit software was applied for the statistical analysis of various data sets obtained from AFM imaging, using power spectrum, variogram and wavelet methods to determine the Hurst exponent. The variogram method proved to be the most suitable to describe biofilm surface profiles with consistent values of ± 0.9, indicating that biofilm growth behaviour will continue in a similar pattern. Fractal dimension values of images obtained from epifluorescence microscopy was determined by the box dimension method. The values described the self-affine patterns displayed by biofilms. Using the results of these investigations, a series of models concerning the initial stages of biofilm formation was compared to describe the development of colony patterns. This study showed that the AFM and epifluorescence microscopy can be used as analytical tools for raw data assembly. It also demonstrated a novel application of existing statistical methods in order to describe the early stages of biofilm formation. Using this approach it was shown that the early stages of biofilm formation display certain colony patterns that can be described and predicted. Such information may be used in efforts to control biofilm formation. / AFRIKAANSE OPSOMMING: Komplekse biofilmgemeenskappe is reeds breedvoerig m die verlede bestudeer. Minder werk is op vroeë stadiums van biofilmvorming gedoen. Hierdie studie het gepoog om die aanvanklike koloniseringspatrone van biofilmvorming op verskillende substrate en onder verskillende omgewingstoestande kwantitatief te bepaal met nuwe metodes om die oppervlakprofiele van biofilms te beskryf. Biofilms is gekweek op glas, polivinielchloried (PVC) en gepoleerde vlekvrye staal. Resultate van mikroskopie, gevolg deur wiskundige analise en kontakhoek-metings het getoon dat glas die mees geskikte substraat vir hierdie studie is. Die produksie van meer ektrasellulêre polimeriese substanse (EPS) en oënskynlik minder selaanhegting is waargeneem op PVC en gepoleerde vlekvrye staaloppervlaktes. Twee verskillende reekse eksperimente IS uitgevoer waar biofilms op glas gekweek IS. Biofilm-morfologie is geanaliseer onder verskillende toestande van temperatuur en nutriënt-konsentrasie. Verskillende temperatuur-toestande was goC, 22°C en 37°C en verskillende nutriënt-konsentrasies was 0.1%, 1% en 10% Tryptic Soy Broth (TSB). Nadat monsters onderskeidelik na 1, 2, 3 en 4 dae verkry is, is die biofilm oppervlaktes gevisualiseer deur atoomkrag mikroskopie (AFM) en epi-fluoressensie mikroskopie. Minder selaanhegting is waargeneem by laer temperature en nutriënt-beperkinge. Die grofheidsprofiele van die vroeë stadium van biofilm-ontwikkeling is ondersoek deur die nuwe toepassing van verskeie bestaande statistiese metodes. Benoit-sagteware is gebruik om die statistiese analise van verskeie data-stelle van AFM beelde te ondersoek deur power spectrum, variogram en wave/et -metodes te gebruik om die Hurst-eksponent te bepaal. Die variogram metode het voorgekom as die mees geskikte om biofilm oppervlakprofiele te beskryf met konstante waardes van ± 0.9, wat aandui dat biofilm groei sal aanhou in 'n soortgelyke patroon. Fraktale dimensie-waardes van beelde wat met epi-fluoressensie mikroskopie verkry is bepaal deur toepassing van Benoit-sagteware se box dimension metode. Die waardes beskryf die selfherhalende patrone wat deur biofilms gedemonstreer word. Deur die resultate van hierdie ondersoeke te gebruik, is 'n reeks modelle aangaande die aanvanklike stadiums van biofilmvorming vergelyk om die ontwikkeling van koloniepatrone te beskryf. Hierdie studie het getoon dat die AFM en epi-fluoressensie mikroskopie gebruik kan word as analitiese gereedskap vir rou data-versameling. 'n Nuwe toepassing van bestaande statistiese metodes om die vroeë stadiums van biofilmvorming te beskryf, is ook gedemonstreer. Deur hierdie benadering te gebruik, is getoon dat die vroeë stadiums van biofilmvorming sekere koloniepatrone aandui wat beskryf en voorspel kan word. Sulke inligting kan gebruik word in pogings om biofilmvorming te beheer.