Browsing by Author "Shirtliff, Mark E."

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Acute septic arthritis
(2002-10) Shirtliff, Mark E.; Mader, Jon T.
Acute septic arthritis may develop as a result of hematogenous seeding, direct introduction, or extension from a contiguous focus of infection. The pathogenesis of acute septic arthritis is multifactorial and depends on the interaction of the host immune response and the adherence factors, toxins, and immunoavoidance strategies of the invading pathogen. Neisseria gonorrhoeae and Staphylococcus aureus are used in discussing the host-pathogen interaction in the pathogenesis of acute septic arthritis. While diagnosis rests on isolation of the bacterial species from synovial fluid samples, patient history, clinical presentation, laboratory findings, and imaging studies are also important. Acute nongonococcal septic arthritis is a medical emergency that can lead to significant morbidity and mortality. Therefore, prompt recognition, rapid and aggressive antimicrobial therapy, and surgical treatment are critical to ensuring a good prognosis. Even with prompt diagnosis and treatment, high mortality and morbidity rates still occur. In contrast, gonococcal arthritis is often successfully treated with antimicrobial therapy alone and demonstrates a very low rate of complications and an excellent prognosis for full return of normal joint function. In the case of prosthetic joint infections, the hardware must be eventually removed by a two-stage revision in order to cure the infection.
The application of biofilm science to the study and control of bacterial infections
(2003-11) Costerton, J. William; Veeh, Richard Harold; Shirtliff, Mark E.; Pasmore, M.; Post, C.; Ehrlich, Garth D.
Unequivocal direct observations have established that the bacteria that cause device-related and other chronic infections grow in matrix-enclosed biofilms. The diagnostic and therapeutic strategies that have served us so well in the partial eradication of acute epidemic bacterial diseases have not yielded accurate data or favorable outcomes when applied to these biofilm diseases. We discuss the potential benefits of the application of the new methods and concepts developed by biofilm science and engineering to the clinical management of infectious diseases.
Assessment of the ability of the bioelectric effect to eliminate mixed-species biofilms
(2005-10) Shirtliff, Mark E.; Bargmeyer, Alex Martin; Camper, Anne K.
Microbes have been able to persist in water distribution systems through the development of multicellular communities known as biofilms. This study evaluated the usefulness of the bioelectric effect for the elimination of water distribution system biofilms from annular reactors. The bioelectric effect did not have any bactericidal action either alone or when coupled with free chlorine.
Basic science of musculoskeletal infections
(2003-01) Shirtliff, Mark E.; Leid, Jeff G.; Costerton, J. William
Biofilms, biomaterials and device-related infections
(2004) Costerton, J. William; Stoodley, Paul; Shirtliff, Mark E.; Pasmore, M.; Cook, Guy S.
Can laboratory reference strains mirror 'real-world' pathogenesis?
(2005-02) Fux, C. A.; Shirtliff, Mark E.; Stoodley, Paul; Costerton, J. William
The extraordinary plasticity of bacterial genomes raises concerns about the adequacy of laboratory-adapted reference strains for the study of 'real world' pathogenesis. Some laboratory strains have been sub-cultured for decades since their first isolation and might have lost important pathophysiological characteristics. Evidence is presented that bacteria rapidly adapt to in vitro conditions. Genomic differences between laboratory reference strains and corresponding low-passage clinical isolates are reviewed. It appears that no bacterial strain can truly represent its species. For DNA microarray and proteomic studies, this limitation might be overcome by the summation of individual genomes to produce a species-specific virtual supragenome.
Comparative evaluation of oral levofloxacin and parenteral nafcillin in the treatment of experimental methicillin-susceptible staphylococcus aureus osteomyelitis in rabbits
(2001-08) Shirtliff, Mark E.; Calhoun, Jason H.; Mader, Jon T.
Methicillim-susceptible Staphylococcus aureus (MSSA) is the most common pathogen recovered from osteomyelitis patients. The current standard therapeutic method for acute phase osteomyelitis is parenteral anitbiotic therapy. However, parental administration has negative aspects, such as secondary infection, patient inconvenience and high cost. The use of single oral antibiotic therapy may alleviate these problems. Therefore, the purpose of this study was to compare the effectiveness of standard once per day dosing of oral levofloxcin with a standard parenteral antibiotic regimen (nafcillin four times daily) for the treatment of experimental MSSA osteomyelitis in rabbits. Nearly all tibias from untreated infected controls (n = 27) revealed positive cultures (93%) for S. aureus, while the levofloxacin-treated group (n = 20) demonstrated significantly lower percentages of S. aureus infection (50%). The infected tibias of the nafcillin-treated group (n = 20) demonstrated significantly lower percentages (10%) of infected tibias than wither the controls or the levoflaxcin-treated groups (p < 0.05). The inferior efficacy of levoflaxcin may have been due to the pharmacokinetic profile of this fluorouinolone. The serum kinetics demonstrated that following single dose administration, levofloxacin was almost undetectable after 12 h. Studies in which levofloxacin is dosed every 12 h or given at increased doses in order to obtain bactericidal concentrations throughout the treatment regimen are needed.
Detection of staphylococcus aureus biofilm on tampons and menses components
(2003-08) Veeh, Richard Harold; Shirtliff, Mark E.; Petik, Jill R.; Flood, Janine A.; Davis, Catherine C.; Seymour, Jon L.; Hansmann, Melanie A.; Kerr, Kathy M.; Pasmore, M.; Costerton, J. William
Culturing has detected vaginal Staphylococcus aureus in 10%–20% of women. Because growth mode can affect virulence expression, this study examined S. aureus–biofilm occurrence in 44 paired—tampon and vaginal-wash—specimens from 18 prescreened women, using fluorescent in situ hybridization (FISH). All 44 specimens were also analyzed for S. aureus by standard culturing on mannitol salt agar, which produced positive results for 15 of the 44 specimens. FISH detected S. aureus cells in all 44 specimens, and S. aureus biofilm was observed in 37 of the 44 specimens. Independent confirmation of the presence of S. aureus in specimens from all 18 women was also obtained by amplification, via polymerase chain reaction, of an S. aureus–specific nuclease gene. The results of this study demonstrate that S. aureusbiofilm can form on tampons and menses components in vivo. Additionally, the prevalence of vaginal S. aureus carriage may be more prevalent than what is currently demonstrated by standard culturing techniques
Experimental osteomyelitis treatment with antibiotic-impregnated hydroxyapatite
(2002-08) Shirtliff, Mark E.; Calhoun, Jason H.; Mader, Jon T.
A calcium hydroxyapatite antibiotic implant was evaluated to determine its efficacy as an antibiotic delivery system in a localized osteomyelitis rabbit model. Localized rabbit tibial osteomyelitis was developed with an intramedullary injection of methicillin resistant Staphylococcus aureus. Infected rabbits were randomized and divided into eight groups depending on treatment with or without debridement, systemic antibiotics, antibiotic-impregnated polymethylmethacrylate beads, or calcium hydroxyapatite implants with and without antibiotic impregnation. All treatments began 2 weeks after infection. After 4 weeks of therapy, the involved bones were cultured for concentrations of Staphylococcus aureus per gram of bone. Rabbits (n = 11) that had calcium hydroxyapatite (impregnated with vancomycin) implanted into the dead space after the debridement surgery had an 81.8% infection clearance after treatment. Rabbits (n = 10) that had polymethylmethacrylate beads (impregnated with vancomycin) implanted into the dead space after debridement surgery had a 70% clearance rate. All other treatment modalities resulted in less than 50% clearance rates. Calcium hydroxyapatite may be an effective alternative to polymethylmethacrylate for providing local antibiotic therapy in cases of methicillin resistant Staphylococcus aureus osteomyelitis.
Gatifloxacin efficacy in treatment of experimental methicillin-sensitive staphylococcus aureus-induced osteomyelitis in rabbits
(2002-01) Shirtliff, Mark E.; Calhoun, Jason H.; Mader, Jon T.
The effectiveness of oral gatifloxacin was compared to that of standard parenteral antibiotic therapy (nafcillin) for the treatment of experimental methicillin-sensitive Staphylococcus aureus-induced osteomyelitis in a rabbit model. Gatifloxacin was as effective as nafcillin in clearing the infection. Therefore, oral gatifloxacin treatment of osteomyelitis may be an effective alternative to intravenous nafcillin treatment.
Host reactions to biomaterials and their evaluation
(2004) Anderson, Jacob Michael; Cook, Guy S.; Costerton, J. William; Hanson, S. R.; Hensten-Pettersen, Arne; Jacobsen, Nils; Johnson, Richard J.; Mitchell, Richard N.; Pasmore, M.; Schoen, Frederick J.; Shirtliff, Mark E.; Stoodley, Paul
Human leukocytes adhere, penetrate, and respond to Staphylococcus aureus biofilms
(2002-11) Leid, Jeff G.; Shirtliff, Mark E.; Costerton, J. William; Stoodley, Paul
Staphylococcus aureus is a common pathogen responsible for nosocomial and community infections. It readily colonizes indwelling catheters, forming microbiotic communities termed biofilms. S. aureus bacteria in biofilms are protected from killing by antibiotics and the body's immune system. For years, one mechanism behind biofilm resistance to attack from the immune system's sentinel leukocytes has been conceptualized as a deficiency in the ability of the leukocytes to penetrate the biofilm. We demonstrate here that under conditions mimicking physiological shear, leukocytes attach, penetrate, and produce cytokines in response to maturing and fully matured S. aureus biofilm.
Identification of Staphylococcus aureus proteins recognized by the antibody-mediated immune response to a biofilm infection
(2006-05) Brady, Rebecca A.; Leid, Jeff G.; Camper, Anne K.; Costerton, J. William; Shirtliff, Mark E.
Staphylococcus aureus causes persistent, recurrent infections (e.g., osteomyelitis) by forming biofilms. To survey the antibody-mediated immune response and identify those proteins that are immunogenic in an S. aureus biofilm infection, the tibias of rabbits were infected with methicillin-resistant S. aureus to produce chronic osteomyelitis. Sera were collected prior to infection and at 14, 28, and 42 days postinfection. The sera were used to perform Western blot assays on total protein from biofilm grown in vitro and separated by two-dimensional gel electrophoresis. Those proteins recognized by host antibodies in the harvested sera were identified via matrix-assisted laser desorption ionization–time of flight analysis. Using protein from mechanically disrupted total and fractionated biofilm protein samples, we identified 26 and 22 immunogens, respectively. These included a cell surface-associated -lactamase, lipoprotein, lipase, autolysin, and an ABC transporter lipoprotein. Studies were also performed using microarray analyses and confirmed the biofilm-specific up-regulation of most of these genes. Therefore, although the biofilm antigens are recognized by the immune system, the biofilm infection can persist. However, these proteins, when delivered as vaccines, may be important in directing the immune system toward an early and effective antibody-mediated response to prevent chronic S. aureus infections. Previous works have identified S. aureus proteins that are immunogenic during acute infections, such as sepsis. However, this is the first work to identify these immunogens during chronic S. aureus biofilm infections and to simultaneously show the global relationship between the antigens expressed during an in vivo infection and the corresponding in vitro transcriptomic and proteomic gene expression levels.
Imaging in osteomyelitis and septic arthritis
(2003) Shirtliff, Mark E.; Mader, Jon T.
The diagnosis of osteomyelitis and septic arthritis depends on clinical presentation, appropriate cultures, laboratory tests, and imaging studies. During the initial evaluation of a patient suspected of having these musculoskeletal infections, radiography, ultrasound, magnetic resonance imaging (MRI) or computed tomography (CT), and radionuclide scans selectively are ordered to assist in the diagnosis, assess the extent of involvement, and guide the site selection for the bone biopsy. Conventional radiography should be performed on all patients. Radiographic changes in early osteomyelitis often are difficult to interpret and lag at least 2 weeks behind the evolution of infection. In patients with septic arthritis, radiographic images often are not revealing in the first few days of infection. However, initial radiographic images may be used to determine associated conditions such as osteoarthritis or simultaneous osteomyelitis, or to exclude neoplasm or injury. Therefore, after the infectious or inflammatory process has been detected and localized with this technique, further examinations by CT, MRI, biopsy, and cultures may be necessary to delineate the extent and etiology of the process. The use of ultrasound in the diagnosis of osteomyelitis is limited to the detection of soft tissue abnormalities around the bone. Ultrasound is a very powerful tool to detect early fluid effusions and to guide initial joint aspiration and drainage procedures. Ultrasound is the method of choice for treatment of patients with acute septic arthritis. CT provides images that display high spatial resolution and explicit cortical bony detail in patients with osteomyelitis. However, CT scans have limited use during the early stages of septic arthritis. MRI is superior to CT in localizing marrow extension and soft tissue changes. In patients with vertebral osteomyelitis, MRI should be used. MRI has the highest accuracy of all imaging techniques. The spatial resolution of MRI makes it more useful than CT or scintigraphy in the diagnosis of septic arthritis. Imaging with radiopharmaceuticals provides information regarding the pathophysiologic and pathobiochemical processes of inflammation, whereas radiography provides high-resolution morphologic information about the pathologic process. Technetium-99m methylene diphosphonate (99mTc MDP) usually is positive in biopsy-confirmed cases of hematogenous osteomyelitis. However, conditions that result in bone injury and repair cause constant bone turnover and focal uptake of 99mTc in bone. Using a three-phase 99mTc MDP followed by gallium-67 imaging increases specificity. Indium-111-labeled white blood cell (In-111 WBC) scintigraphy is very sensitive (except in some cases of chronic osteomyelitis), specific, and the method of choice for diagnosing and localizing distal appendicular skeletal osteomyelitis.
Immunology of staphylococcal biofilm infections in the eye: new tools to study biofilm endophthalmitis
(2002-05) Leid, Jeff G.; Costerton, J. William; Shirtliff, Mark E.; Gilmore, Michael S.; Engelbert, Michael
Endophthalmitis is an important disease of the eye that is most frequently caused by postoperative and posttraumatic introduction of bacteria into the posterior segment of the eye. In the case of severe infections, visual acuity is greatly damaged or completely lost. Much work has focused on the ability of planktonic bacteria to cause infection and ocular damage while little work has focused on chronic infections in endophthalmitis mediated by the formation of bacterial biofilms on the surface of the lens. This review focuses on the interaction of Staphylococcus aureus and Staphylococcus epidermidis lens-associated biofilms in endophthalmitis. Additionally, this review highlights some relevant biofilm-immune system interactions and outlines a new in vivo mouse model to explore biofilm-related infections in endophthalmitis.
The importance of a multifaceted approach to characterizing the microbial flora of chronic wounds
(2011-09) Han, Anne; Zenilman, Jonathan M.; Melendez, J. H.; Shirtliff, Mark E.; Agostinho, Alessandra; James, Garth A.; Stewart, Philip S.; Mongodin, E. F.; Rao, D.; Rickard, A. H.; Lazarus, Gerald S.
Chronic wounds contain complex polymicrobial communities of sessile organisms that have been underappreciated because of limitations of standard culture techniques. The aim of this work was to combine recently developed next-generation investigative techniques to comprehensively describe the microbial characteristics of chronic wounds.Tissue samples were obtained from 15 patients with chronic wounds presenting to the Johns Hopkins Wound Center. Standard bacteriological cultures demonstrated an average of three common bacterial species in wound samples. By contrast, high-throughput pyrosequencing revealed increased bacterial diversity with an average of 17 genera in each wound. Data from microbial community profiling of chronic wounds were compared with published sequenced analyses of bacteria from normal skin. Increased proportions of anaerobes, gram-negative rods and gram-positive cocci were found in chronic wounds. In addition, chronic wounds had significantly lower populations of Propionibacterium compared with normal skin. Using epifluorescence microscopy, wound bacteria were visualized in highly organized thick confluent biofilms or as scattered individual bacterial cells. Fluorescent in situ hybridization allowed for the visualization of Staphylococcus aureus cells in a wound sample. Quorum-sensing molecules were measured by bioassay to evaluate signaling patterns among bacteria in the wounds. A range of autoinducer-2 activities was detected in the wound samples. Collectively, these data provide new insights into the identity, organization, and behavior of bacteria in chronic wounds. Such information may provide important clues to effective future strategies in wound healing.
Minimum information about a biofilm experiment (MIABiE): Standards for reporting experiments and data on sessile microbial communities living at interfaces
(2014-02) Lourenco, A.; Coenye, T.; Goeres, Darla M.; Donelli, G.; Azevedo, A. S.; Ceri, H.; Coelho, F. L.; Flemming, H.-C.; Juhna, T.; Lopes, S. P.; Oliveira, R.; Oliver, A.; Shirtliff, Mark E.; Sousa, A. M.; Stoodley, Paul; Pereira, M. O.; Azevedo, N. F.
The minimum information about a biofilm experiment (MIABiE) initiative has arisen from the need to find an adequate and scientifically sound way to control the quality of the documentation accompanying the public deposition of biofilm-related data, particularly those obtained using high-throughput devices and techniques. Thereby, the MIABiE consortium has initiated the identification and organization of a set of modules containing the minimum information that needs to be reported to guarantee the interpretability and independent verification of experimental results and their integration with knowledge coming from other fields. MIABiE does not intend to propose specific standards on how biofilms experiments should be performed, because it is acknowledged that specific research questions require specific conditions which may deviate from any standardization. Instead, MIABiE presents guidelines about the data to be recorded and published in order for the procedure and results to be easily and unequivocally interpreted and reproduced. Overall, MIABiE opens up the discussion about a number of particular areas of interest and attempts to achieve a broad consensus about which biofilm data and metadata should be reported in scientific journals in a systematic, rigorous and understandable manner.
Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates
(2020-12) Allkja, Jontana; Bjarnsholt, Thomas; Coenye, Tom; Cos, Paul; Fallarero, Adyary; Harrison, Joe J.; Lopes, Susana P.; Oliver, Antonio; Pereira, Maria Olivia; Ramage, Gordon; Shirtliff, Mark E.; Stoodley, Paul; Webb, Jeremy S.; Zaat, Sebastian A. J.; Goeres, Darla M.; Azevedo, Nuno Filipe
The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.
Minimum information guideline for spectrophotometric and ﬂuorometric methods to assess bioﬁlm formation in microplates
(Elsevier BV, 2020) Allkja, Jontana; Bjarnsholt, Thomas; Coenye, Tom; Cos, Paul; Fallarero, Adyary; Harrison, Joe J.; Lopes, Susana P.; Oliver, Antonio; Pereira, Maria Olivia; Ramage, Gordon; Shirtliff, Mark E.; Stoodley, Paul; Webb, Jeremy S.; Zaat, Sebastian A.J.; Goeres, Darla M.; Azevedo, Nuno Filipe
The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.
Molecular interactions in biofilms
(2002-08) Shirtliff, Mark E.; Mader, Jon T.; Camper, Anne K.
A biofilm may be defined as a microbially derived, sessile community characterized by cells that are attached to an interface, embedded in a matrix of exopolysaccharide, and demonstrate an altered phenotype. This review covers the current understanding of the nature of biofilms and the impact that molecular interactions may have on biofilm development and phenotype using the motile gram-negative rod Pseudomonas aeruginosa and the nonmotile gram-positive cocci Staphylococcus aureus as examples.