Biomedical subjects

John G Thomas

Publications and source records attributed to John G Thomas.

6 recordsLinked to original sources

PubMed2006

Managing the complexity of a dynamic biofilm.

BACKGROUND: This article provides an overview of the history of oral microbiology, a discussion of dental plaque as both a microbial community and a biofilm, and a review of the measures available to control the oral microflora. TYPES OF STUDIES REVIEWED: The authors reviewed the literature related to oral microbiology and associated infectious diseases. They also examined articles that detailed the structure and physiology of biofilms, including dental plaque biofilms. CONCLUSIONS: Biofilms cannot be eliminated. The pathogenic nature of the dental plaque biofilm can be diminished in the oral cavity by reducing the bioburden and effectively maintaining a normal oral flora via oral hygiene procedures that include daily toothbrushing, flossing and rinsing with an antimicrobial mouthrinse. An oral hygiene regimen that includes rinsing with an antimicrobial mouthrinse is a practical approach to the prevention and management of periodontal diseases. This strategy may have wider benefits when the link between periodontal disease and certain systemic diseases is considered. CLINICAL IMPLICATIONS: An effective oral hygiene regimen can help control dental plaque biofilm and associated periodontal diseases.

Biofilms↗

PubMed2005

Chronic rhinosinusitis and biofilms.

BACKGROUND AND HYPOTHESIS: Biofilms have been implicated in several head and neck infectious processes such as the following: dental and periodontal disease, otitis media, tympanostomy tube otorrhea, and chronic tonsillitis. We believe that biofilms also are associated with chronic rhinosinusitis. No information is known regarding the presence of biofilms in chronic rhinosinusitis. STUDY DESIGN AND SETTING: With institutional review board approval, tissue was obtained from consenting chronic rhinosinusitis patients who were undergoing functional endoscopic sinus surgery. Specimens were taken bilaterally from the ethmoid and maxillary sinuses. Inclusion criteria consisted of a positive diagnosis with pathologic tissue confirmation of chronic inflammation. Diagnosis was based on patient history, physical exam, and coronal sinus CT findings. Once collected, the specimens were labeled and fixed in formalin. The specimens were subsequently dehydrated, with successive immersions in increasing concentrations of diluted ethanol. The specimens were allowed to air dry and then were affixed to aluminum stubs with colloidal carbon. The sample surface was coated with a gold and palladium layer. The specimens were examined under an electron microscope. Areas of interest were photographed. RESULTS: Specimens from 5 patients were examined. All revealed bacterial biofilms. Invariably, biofilms were seen in the ethmoid, as well as in other samples. Denudation of ciliated and goblet cells was noted in all specimens. Biofilms resembled that of Staphylococcus species. Unidentified biofilms were also seen. CONCLUSIONS: This is the first documentation of biofilms in association with chronic rhinosinusitis. Further investigation is warranted, especially with control research subjects.

Adult↗

PubMed2004

Computerized antimicrobial decision support: an offline evaluation of a database-driven empiric antimicrobial guidance program in hospitalized patients with a bloodstream infection.

INTRODUCTION: We developed a computerized antimicrobial guidance program based on the last 5 years of our laboratory culture data augmented by expert infectious disease logic. The program is designed to assist physicians with the targeting of empiric antimicrobials for hospitalized patients by tracking pathogenic bacteria and their evolving antimicrobial resistance profiles. Costs, toxicities, and environmental impact of antimicrobial use also influence the final recommendations. We undertook the following analysis to verify its potential safety and efficacy in hospitalized patients with a bloodstream infection. METHODS: We retrospectively enrolled all inpatients with a positive blood culture for a previously undetermined pathogen during the first 6 months of 2002 and determined the empiric therapy initiated within the 12h before and after the time of culture. Antimicrobial recommendations from the microbiologic decision support tool were then determined by matching specimen (blood), hospital unit, community- versus hospital-acquired category, age category, and gender. Generated antimicrobial recommendations were tailored to patient allergies, age category, and presence of pregnancy, lactation, or hepatic impairment. RESULTS: The microbiology laboratory recorded 226 unique patient/pathogen blood cultures during the study period. Physicians initiated effective empiric therapy in 150 of the 226 cases, for an effectiveness rate of 66%. The computer-guided therapy was effective in 195 of the 226 cases for a rate of 86%. A contingency table analysis showed 55 cases where the computer recommendation was effective but the physicians' selection was not, and eight cases where the physicians' antimicrobials were effective but the computer's were not (P < 0.0001). DISCUSSION: For patients with a bloodstream infection, we found that our computer-guided statistically-derived antimicrobial therapy would potentially improve the rate of effectiveness of empirically chosen antimicrobials.

Anti-Bacterial Agents↗

PubMed2003

Forward and backward recall: different response time patterns, same retrieval order.

How do people retrieve information in forward and backward recall? To address this issue, we examined response times in directional recall as a function of serial position and list length. Participants memorized lists of four to six words and entered responses at the keyboard. Recall direction was postcued. Response times exhibited asymmetry in terms of direction. In forward recall, response times peaked at the first position, leveling off for subsequent positions. Response times were slower in backward recall than in forward recall and exhibited an inverse U-shaped function with an initial slowdown followed by a continuous speedup. These asymmetries have implications for theoretical models of retrieval in serial recall, including temporal-code, rule-based, and network models. The response time pattern suggests that forward recall proceeds in equal steps across positions, whereas backward recall involves repeated covert cycles of forward recall. Thus, retrieval in both directions involves a forward search.

Adolescent↗

PubMed2003

Database-driven computerized antibiotic decision support: novel use of expert antibiotic susceptibility rules embedded in a pathogen-antibiotic logic matrix.

To better serve an antibiotic guidance program, we hypothesized that the relatively few antibiotic susceptibility measurements conducted in the microbiology laboratory could be extended to predict antibiotic susceptibilities for all antibiotics on the hospital formulary using expert infectious disease logic. With the assistance of infectious disease specialists, we developed these logic rules and then applied them to 26,196 unique patient culture specimens and the accompanying 334,131 antibiotic susceptibility measurements generating 804,809 additional predicted bug-drug susceptibility data points. From the resulting data set, the antibiotic susceptibility profile for one pathogen, Streptococcus pneumoniae, is highlighted herein. We then incorporated the extended susceptibility profiles into a computerized antibiotic guidance program that matches current patients of interest with the positive cultures from past similar patients and calculates predicted effective antibiotic therapy. We conclude that this method successfully derives antibiotic predictions and merits further testing to evaluate its potential use in the hospital environment.

Anti-Bacterial Agents↗

PubMed2003

Computerized antimicrobial decision support for hospitalized patients with a bloodstream infection.

We developed a computerized antimicrobial decision support program founded on our local bacterial susceptibility data. In a retrospective analysis of patients with a bloodstream infection, we compared the actual antimicrobials prescribed to the antimicrobials recommended by the program. We found the computer-guided therapy to be clinically and statistically more effective than the therapy initiated by the physicians. We conclude that computerized decision support can improve the targeting of empiric antimicrobial therapy.

Anti-Infective Agents↗