Biofilms are complex communities of microorganisms attached to surfaces or associated with interfaces. Despite the focus of modern microbiology research on pure culture, planktonic (free-swimming) bacteria, it is now widely recognized that most bacteria found in natural, clinical, and industrial settings persist in association with surfaces. Furthermore, these microbial communities are often composed of multiple species that interact with each other and their environment. The determination of biofilm architecture, particularly the spatial arrangement of microcolonies (clusters of cells) relative to one another, has profound implications for the function of these complex communities. Numerous new experimental approaches and methodologies have been developed in order to explore metabolic interactions, phylogenetic groupings, and competition among members of the biofilm. To complement this broad view of biofilm ecology, individual organisms have been studied using molecular genetics in order to identify the genes required for biofilm development and to dissect the regulatory pathways that control the plankton-to-biofilm transition. These molecular genetic studies have led to the emergence of the concept of biofilm formation as a novel system for the study of bacterial development. The recent explosion in the field of biofilm research has led to exciting progress in the development of new technologies for studying these communities, advanced our understanding of the ecological significance of surface-attached bacteria, and provided new insights into the molecular genetic basis of biofilm development.

Microbial Biofilms: from Ecology to Molecular Genetics

Timothy H. Dellit, Robert C. Owens, John E. McGowan, Jr., Dale N. Gerding, Robert A. Weinstein, John P. Burke, W. Charles Huskins, David L. Paterson, Neil O. Fishman, Christopher F. Carpenter, P. J. Brennan, Marianne Billeter, and Thomas M. Hooton Harborview Medical Center and the University of Washington, Seattle; Maine Medical Center, Portland; Emory University, Atlanta, Georgia; Hines Veterans Affairs Hospital and Loyola University Stritch School of Medicine, Hines, and Stroger (Cook County) Hospital and Rush University Medical Center, Chicago, Illinois; University of Utah, Salt Lake City; Mayo Clinic College of Medicine, Rochester, Minnesota; University of Pittsburgh Medical Center, Pittsburgh, and University of Pennsylvania, Philadelphia, Pennsylvania; William Beaumont Hospital, Royal Oak, Michigan; Ochsner Health System, New Orleans, Louisiana; and University of Miami, Miami, Florida

/pdf/infectious-diseases-society-of-america-and-the-society-for-34gfecer7v.pdf

Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America Guidelines for Developing an Institutional Program to Enhance Antimicrobial Stewardship

https://www.cdc.gov/coronavirus/mers/downloads/Isolation2007.pdf

2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings.

Ventilator-associated pneumonia (VAP) continues to complicate the course of 8 to 28% of patients receiving mechanical ventilation (MV). In contrast to infections of more frequently involved organs (e.g., urinary tract and skin), for which mortality is low, ranging from 1 to 4%, the mortality rate for VAP ranges from 24 to 50% and can reach 76% in some specific settings or when lung infection is caused by high-risk pathogens. The predominant organisms responsible for infection are Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae, but etiologic agents widely differ according to the population of patients in an intensive care unit, duration of hospital stay, and prior antimicrobial therapy. Because appropriate antimicrobial treatment of patients with VAP significantly improves outcome, more rapid identification of infected patients and accurate selection of antimicrobial agents represent important clinical goals. Our personal bias is that using bronchoscopic techniques to obtain protected brush and bronchoalveolar lavage specimens from the affected area in the lung permits physicians to devise a therapeutic strategy that is superior to one based only on clinical evaluation. When fiberoptic bronchoscopy is not available to physicians treating patients clinically suspected of having VAP, we recommend using either a simplified nonbronchoscopic diagnostic procedure or following a strategy in which decisions regarding antibiotic therapy are based on a clinical score constructed from seven variables. Selection of the initial antimicrobial therapy should be based on predominant flora responsible for VAP at each institution, clinical setting, information provided by direct examination of pulmonary secretions, and intrinsic antibacterial activities of antimicrobial agents and their pharmacokinetic characteristics. Further trials will be needed to clarify the optimal duration of treatment and the circumstances in which monotherapy can be safely used.

Ventilator-associated pneumonia.

Cryptococcosis is a global invasive mycosis associated with significant morbidity and mortality. These guidelines for its management have been built on the previous Infectious Diseases Society of America guidelines from 2000 and include new sections. There is a discussion of the management of cryptococcal meningoencephalitis in 3 risk groups: (1) human immunodeficiency virus (HIV)-infected individuals, (2) organ transplant recipients, and (3) non-HIV-infected and nontransplant hosts. There are specific recommendations for other unique risk populations, such as children, pregnant women, persons in resource-limited environments, and those with Cryptococcus gattii infection. Recommendations for management also include other sites of infection, including strategies for pulmonary cryptococcosis. Emphasis has been placed on potential complications in management of cryptococcal infection, including increased intracranial pressure, immune reconstitution inflammatory syndrome (IRIS), drug resistance, and cryptococcomas. Three key management principles have been articulated: (1) induction therapy for meningoencephalitis using fungicidal regimens, such as a polyene and flucytosine, followed by suppressive regimens using fluconazole; (2) importance of early recognition and treatment of increased intracranial pressure and/or IRIS; and (3) the use of lipid formulations of amphotericin B regimens in patients with renal impairment. Cryptococcosis remains a challenging management issue, with little new drug development or recent definitive studies. However, if the diagnosis is made early, if clinicians adhere to the basic principles of these guidelines, and if the underlying disease is controlled, then cryptococcosis can be managed successfully in the vast majority of patients.

/pdf/clinical-practice-guidelines-for-the-management-of-4n4mku8a14.pdf

Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the infectious diseases society of america.

Objective. —To provide hospital leaders with strategic goals or actions likely to have a significant impact on antimicrobial resistance, outline outcome and process measures for evaluating progress toward each goal, describe potential barriers to success, and suggest countermeasures and novel improvement strategies. Participants. —A multidisciplinary group of experts was drawn from the following areas: hospital epidemiology and infection control, infectious diseases (including graduate training programs), clinical practice (including nursing, surgery, internal medicine, and pediatrics), pharmacy, administration, quality improvement, appropriateness evaluation, behavior modification, practice guideline development, medical informatics, and outcomes research. Representatives from appropriate federal agencies, the Joint Commission on Accreditation of Healthcare Organizations, and the pharmaceutical industry also participated. Evidence. —Published literature, guidelines, expert opinion, and practical experience regarding efforts to improve antibiotic utilization and prevent and control the emergence and dissemination of antimicrobial-resistant microorganisms in hospitals. Consensus Process. —Participants were divided into two quality improvement teams: one focusing on improving antimicrobial usage and the other on preventing and controlling transmission of resistant microorganisms. The teams modeled the process a hospital might use to develop and implement a strategic plan to combat antimicrobial resistance. Conclusions. —Ten strategic goals and related process and outcome measures were agreed on. The five strategic goals to optimize antimicrobial use were as follows: optimizing antimicrobial prophylaxis for operative procedures; optimizing choice and duration of empiric therapy; improving antimicrobial prescribing by educational and administrative means; monitoring and providing feedback regarding antibiotic resistance; and defining and implementing health care delivery system guidelines for important types of antimicrobial use. The five strategic goals to detect, report, and prevent transmission of antimicrobial resistant organisms were as follows: to develop a system to recognize and report trends in antimicrobial resistance within the institution; develop a system to rapidly detect and report resistant microorganisms in individual patients and ensure a rapid response by caregivers; increase adherence to basic infection control policies and procedures; incorporate the detection, prevention, and control of antimicrobial resistance into institutional strategic goals and provide the required resources; and develop a plan for identifying, transferring, discharging, and readmitting patients colonized with specific antimicrobial-resistant pathogens. ( JAMA . 1996;275:234-240)

Strategies to Prevent and Control the Emergence and Spread of Antimicrobial-Resistant Microorganisms in Hospitals: A Challenge to Hospital Leadership

Over 14 years 41 patients were diagnosed as having pulmonary cryptococcosis. Cryptococcus neoformans remained localized to the lung in 12 cases and disseminated in the remaining 29. Thirty-four patients were compromised hosts. Disseminated disease developed in 28 of these 34, and four of these 28 patients with disseminated disease presented with concomitant pulmonary and meningeal infections. In all the remaining 24 central nervous system involvement developed 2 to 20 weeks after the finding of an abnormal chest roentgenogram. Seven patients were normal hosts, and in six of these cases disease remained localized to the lung. Four important conclusions were drawn from this study: pulmonary cryptococcosis is rarely considered in the differential diagnosis of an abnormal chest roentgenogram, thereby leading to missed diagnoses and therapeutic errors; the natural history of untreated pulmonary cryptococcosis in compromised hosts is extrapulmonic dissemination; compromised hosts with pulmonary cryptococcosis should receive antifungal therapy because of a high propensity for dissemination; and normal hosts in whom dissemination has been excluded generally do not need antifungal therapy.

The Evolution of Pulmonary Cryptococcosis: Clinical Implications from a Study of 41 Patients With and Without Compromising Host Factors

Primary amoebic meningoencephalitis caused by Naegleria. Two new cases, response to amphotericin B, and a review.

Between July 1977 and January 1980, seven cases of sporadic, nonepidemic "epidemic" typhus (Rickettsia prowazekii) were discovered in Virginia, West Virginia, and North Carolina. The reservoir seemed to be the southern flying squirrel (Glaucomys volans), an animal indigenous to the eastern United States; however, the vector or mode of acquisition was not evident. Diagnosis was established principally through complement fixation, indirect immunofluorescence, and toxin neutralization tests. Patients' ages were 11 to 81 years. Most were white women. Six had abrupt onset of illness. Headaches, fever, myalgias, and exanthems were among the presenting complaints. The disease seemed milder than classic louse-born epidemic typhus, but in some instances, it was life-threatening. All patients responded to tetracycline or chloramphenicol. This entity probably is more common than reported, is difficult to recognize, and is produced by an organism seemingly identical to that producing louse-born epidemic typhus. (JAMA1981;245:2318-2323)

https://jamanetwork.com/journals/jama/articlepdf/375339/jama_245_22_022.pdf

Epidemic Typhus in the United States Associated With Flying Squirrels

Six pathogenic strains of Naegleria fowleri , two of Acanthamoeba castellanii , and three of Acanthamoeba polyphaga were tested in vitro for susceptibility to a variety of potentially useful therapeutic agents Minimal motility inhibitory concentrations and minimal inhibitory concentrations were determined by a technique of subculturing pure clones of amoebae in plastic tissue culture chamber slides containing liquid axenic media and serially diluted drug, incubating at 30°C for Acanthamoeba and at 37°C for Naegleria , and observing on an inverted microscope at 6 h for inhibition of motility and at 24 and 48 h for inhibition of growth Drug concentrations were selected on the basis of fluid levels achievable in humans Amphotericin B, clotrimazole, and miconazole were the most effective drugs against Naegleria , whereas polymyxin B sulfate and pentamidine isethionate were somewhat effective against pathogenic Acanthamoeba  Our results suggest that amphotericin B is the most effective agent against Naegleria , but few agents are effective against Acanthamoeba  Images

Richard J. Duma

Papers

Strategies to Prevent and Control the Emergence and Spread of Antimicrobial-Resistant Microorganisms in Hospitals: A Challenge to Hospital Leadership

The Evolution of Pulmonary Cryptococcosis: Clinical Implications from a Study of 41 Patients With and Without Compromising Host Factors

Primary amoebic meningoencephalitis caused by Naegleria. Two new cases, response to amphotericin B, and a review.

Epidemic Typhus in the United States Associated With Flying Squirrels

In Vitro Susceptibility of Pathogenic Naegleria and Acanthamoeba Species to a Variety of Therapeutic Agents