Browsing by Author "Hall-Stoodley, Luanne"

Now showing 1 - 13 of 13

Bacterial biofilms: a diagnostic and therapeutic challenge
(2003-12) Fux, C. A.; Stoodley, Paul; Hall-Stoodley, Luanne; Costerton, J. William
Bacteria have traditionally been regarded as individual organisms growing in homogeneous planktonic populations. However, bacteria in natural environments usually form communities of surface-adherent organisms embedded in an extracellular matrix, called biofilms. Current antimicrobial strategies often fail to control bacteria in the biofilm mode of growth. Treatment failure is particularly frequent in association with intracorporeal or transcutaneous medical devices and compromised host immunity. The rising prevalence of these risk factors over the last decades has paralleled the increase in biofilm infections. This review discusses the shortcomings of current therapies against biofilms both in theory and with clinical examples. Biofilm characteristics are described with a focus on new diagnostic and therapeutic targets.
Bacterial biofilms: From the environment to infectious disease
(2004-02) Hall-Stoodley, Luanne; Costerton, J. William; Stoodley, Paul
Biofilms—matrix-enclosed microbial accretions that adhere to biological or non-biological surfaces—represent a significant and incompletely understood mode of growth for bacteria. Biofilm formation appears early in the fossil record (3.25 billion years ago) and is common throughout a diverse range of organisms in both the Archaea and Bacteria lineages, including the 'living fossils' in the most deeply dividing branches of the phylogenetic tree. It is evident that biofilm formation is an ancient and integral component of the prokaryotic life cycle, and is a key factor for survival in diverse environments. Recent advances show that biofilms are structurally complex, dynamic systems with attributes of both primordial multicellular organisms and multifaceted ecosystems. Biofilm formation represents a protected mode of growth that allows cells to survive in hostile environments and also disperse to colonize new niches. The implications of these survival and propagative mechanisms in the context of both the natural environment and infectious diseases are discussed in this review. Full test provided (pdf) with permission of: Future Drugs.
Biofilm formation by the rapidly growing mycobacterial species mycobacterium fortuitum
(1998-11) Hall-Stoodley, Luanne; Lappin-Scott, H. M.
Rapidly growing mycobacteria (RGM) are found in soil and diverse aquatic environments. Two species, Mycobacterium fortuitum and Mycobacterium chelonae, are associated with disease and are difficult to eradicate. Biofilm formation may be a contributing factor to their mode of transmission and their resistance to antimicrobial agents. We investigated the ability of the RGM species M. fortuitum to colonise surfaces using a modified Robbins device. M. fortuitum formed dense biofilms within 48 h. The high numbers of sessile organisms recovered and the swiftness of colonisation suggest that M. fortuitum readily forms biofilms. These results suggest a novel mechanism for mycobacteria in evading antimicrobial treatment and also indicate that biofilms should be considered possible sites for mycobacterial contamination.
The biofilm life cycle: expanding the conceptual model of biofilm formation
(Springer Science and Business Media LLC, 2022-10) Sauer, Karin; Stoodley, Paul; Goeres, Darla M.; Hall-Stoodley, Luanne; Burmølle, Mette; Stewart, Philip S.; Bjarnsholt, Thomas
Bacterial biofilms are often defined as communities of surface-attached bacteria and are typically depicted with a classic mushroom-shaped structure characteristic of Pseudomonas aeruginosa. However, it has become evident that this is not how all biofilms develop, especially in vivo, in clinical and industrial settings, and in the environment, where biofilms often are observed as non-surface-attached aggregates. In this Review, we describe the origin of the current five-step biofilm development model and why it fails to capture many aspects of bacterial biofilm physiology. We aim to present a simplistic developmental model for biofilm formation that is flexible enough to include all the diverse scenarios and microenvironments where biofilms are formed. With this new expanded, inclusive model, we hereby introduce a common platform for developing an understanding of biofilms and anti-biofilm strategies that can be tailored to the microenvironment under investigation.
Community structure and co-operation in biofilms
(2000) Stoodley, Paul; Hall-Stoodley, Luanne; Boyle, John D.; Jørgensen, Frieda; Lappin-Scott, H. M.
Detachment, surface migration, and other dynamic behavior in bacterial biofilms revealed by digital time-lapse imaging
(2001) Stoodley, Paul; Hall-Stoodley, Luanne; Lappin-Scott, H. M.
Developmental regulation of microbial biofilms
(2002-06) Hall-Stoodley, Luanne; Stoodley, Paul
Sophisticated molecular and microscopic methods used to study biofilm formation are rapidly broadening our understanding of surface-attached microbial communities in a wide variety of organisms. Regulatory mechanisms involved in the attachment and subsequent development of mature biofilms are being elucidated. Common themes are beginning to emerge, providing promise for the development of sophisticated control strategies.
Establishment of experimental biofilms using the modified robbins device and flow cells
(1999) Hall-Stoodley, Luanne; Rayner, Joanna; Stoodley, Paul; Lappin-Scott, H. M.
Recent studies have shown that biofilms (a complex organization of bacterial cells present at a surface or interface, which produces a slime-like matrix) represent the principal form of bacterial growth in all environments studied to date (1). There are numerous advantages to bacteria growing in biofilms. These include extended protection against environmental changes, antimicrobial agents such as chemical disinfectants and antibiotics (2) and grazing predators such as amebae (3), as well as providing increased access to limited nutrients (4). Biofilms are of interest in medical, industrial, and natural environments for several reasons. For example, they can act as reservoirs from which the dissemination of pathogens may occur. Legionella pneumophila has been shown to be harbored within biofilms formed within drinking water pipelines (5). Similarly, it is well established that biofilms can colonize numerous types of medical implants (6). In industrial systems, detrimental effects may occur following biofilm growth such as reductions in heat-transfer efficiency and flow capacity. Biofouling may also markedly increase corrosion (7). Finally, biofilms represent a bacterial architecture that may support genetic transfer, nutrient utilization, and biodegradation (8).
Growth and detachment of cell clusters from mature mixed species biofilms
(2001-12) Stoodley, Paul; Wilson, Suzanne; Hall-Stoodley, Luanne; Boyle, John D.; Lappin-Scott, H. M.; Costerton, J. William
Detachment from biofilms is an important consideration in the dissemination of infection and the contamination of industrial systems but is the least-studied biofilm process. By using digital time-lapse microscopy and biofilm flow cells, we visualized localized growth and detachment of discrete cell clusters in mature mixed-species biofilms growing under steady conditions in turbulent flow in situ. The detaching biomass ranged from single cells to an aggregate with a diameter of approximately 500 µm. Direct evidence of local cell cluster detachment from the biofilms was supported by microscopic examination of filtered effluent. Single cells and small clusters detached more frequently, but larger aggregates contained a disproportionately high fraction of total detached biomass. These results have significance in the establishment of an infectious dose and public health risk assessment.
Heligmosomoides polygyrus infection : the role of cytokines in regulation of mast cell development
(Montana State University - Bozeman, College of Agriculture, 1995) Hall-Stoodley, Luanne
The influence of fluid shear on the structure and material properties of sulphate-reducing bacterial biofilms
(2002-12) Dunsmore, B. C.; Jacobsen, A.; Hall-Stoodley, Luanne; Bass, C. J.; Lappin-Scott, H. M.; Stoodley, Paul
Biofilms of sulphate-reducing Desulfovibrio sp. EX265 were grown in square section glass capillary flow cells under a range of fluid flow velocities from 0.01 to 0.4 m/s (wall shear stress, τw, from 0.027 to 1.0 N/m2). In situ image analysis and confocal scanning laser microscopy revealed biofilm characteristics similar to those reported for aerobic biofilms. Biofilms in both flow cells were patchy and consisted of cell clusters separated by voids. Length-to-width ratio measurements (lc:wc) of biofilm clusters demonstrated the formation of more “streamlined” biofilm clusters (lc:wc=3.03) at high-flow velocity (Reynolds number, Re, 1200), whereas at low-flow velocity (Re 120), the lc:wc of the clusters was approximately 1 (lc:wc of 1 indicates no elongation in the flow direction). Cell clusters grown under high flow were more rigid and had a higher yield point (the point at which the biofilm began to flow like a fluid) than those established at low flow and some biofilm cell aggregates were able to relocate within a cluster, by travelling in the direction of flow, before attaching more firmly downstream.
New methods for the detection of orthopedic and other biofilm infections
(2011-03) Costerton, J. William; Post, J. C.; Ehrlich, Garth D.; Hu, Fen Z.; Kreft, R.; Nistico, L.; Kathju, S.; Stoodley, Paul; Hall-Stoodley, Luanne; Maale, G.; James, Garth A.; Sotereanos, N.; DeMeo, P.
The detection and identification of bacteria present in natural and industrial ecosystems is now entirely based on molecular systems that detect microbial RNA or DNA. Culture methods were abandoned in the 1980s because direct observations showed that <1% of the bacteria in these systems grew on laboratory media. Culture methods comprise the backbone of the Food and Drug Administration-approved diagnostic systems used in hospital laboratories, with some molecular methods being approved for the detection of specific pathogens that are difficult to grow in vitro. In several medical specialties, the reaction to negative cultures in cases in which overt signs of infection clearly exist has produced a spreading skepticism concerning the sensitivity and accuracy of traditional culture methods.We summarize evidence from the field of orthopedic surgery, and from other medical specialties, that support the contention that culture techniques are especially insensitive and inaccurate in the detection of chronic biofilm infections. We examine the plethora of molecular techniques that could replace cultures in the diagnosis of bacterial diseases, and we identify the new Ibis technique that is based on base ratios (not base sequences), as the molecular system most likely to fulfill the requirements of routine diagnosis in orthopedic surgery.
Role of biofilms in neurosurgical device-related infections
(2005-10) Baxton Jr, Ernest E.; Ehrlich, Garth D.; Hall-Stoodley, Luanne; Stoodley, Paul; Veeh, Rick; Fux, C. A.; Hu, Fen Z.; Quigley, Matthew; Post, J. C.
Bacterial biofilms have recently been shown to be important in neurosurgical device-related infections. Because the concept of biofilms is novel to most practitioners, it is important to understand that both traditional pharmaceutical therapies and host defense mechanisms that are aimed at treating or overcoming free-swimming bacteria are largely ineffective against the sessile bacteria in a biofilm. Bacterial biofilms are complex surface-attached structures that are composed of an extruded extracellular matrix in which the individual bacteria are embedded. Superimposed on this physical architecture is a complex system of intercellular signaling, termed quorum sensing. These complex organizational features endow biofilms with numerous microenvironments and a concomitant number of distinct bacterial phenotypes. Each of the bacterial phenotypes within the biofilm displays a unique gene expression pattern tied to nutrient availability and waste transport. Such diversity provides the biofilm as a whole with an enormous survival advantage when compared to the individual component bacterial cells. Thus, it is appropriate to view the biofilm as a multicellular organism, akin to metazoan eukaryotic life. Bacterial biofilms are much hardier than free floating or planktonic bacteria and are primarily responsible for device-related infections. Now that basic research has demonstrated that the vast majority of bacteria exist in biofilms, the paradigm of biofilm-associated chronic infections is spreading to the clinical world. Understanding how these biofilm infections affect patients with neurosurgical devices is a prerequisite to developing strategies for their treatment and prevention.