Infectious disease clinics of North America
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Zygomycosis, an uncommon but frequently fatal mycosis caused by fungi of the class Zygomycetes, develops most commonly as an opportunistic disease. Successful therapy involves a combined approach based on early diagnosis, prompt institution of medical therapy, and extensive surgical debridement of all devitalized tissue. Given the rarity of this condition, novel therapeutic strategies have been limited and only tested on an individual basis. The use of high-dose lipid formulations of amphotericin B, prompt reversal of the underlying predisposing condition, and hyperbaric oxygen are the most common strategies that have shown potential value in the treatment of zygomycosis.
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Less common and emerging fungal pathogens are often resistant to conventional antifungal therapy and may cause severe morbidity and mortality in immunocompromised hosts. Some Scedosporium species may be completely resistant to antifungal therapy. Hyaline septated filamentous fungi, such as Fusarium species, Acremonium species, Paecilomyces species, and Trichoderma species, are increasingly reported as causing invasive mycoses refractory to amphotericin B therapy. ⋯ Trichosporon spp are resistant to the fungicidal effects of amphotericin B. An increasing number of different members of the class Zygomycetes are reported as causing lethal infections, despite aggressive medical and surgical interventions. Infections due to these and other less common and emergent fungal pathogens will likely continue to develop in the settings of selective anti-fungal pressure, permissive environmental conditions, and an expanding population of immunocompromised hosts.
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Staphylococcus aureus is a leading cause of bacteremia and endocarditis. Over the past several years, the frequency of S. aureus bacteremia (SAB) has increased dramatically. This increasing frequency, coupled with increasing rates of antibiotic resistance, has renewed interest in this serious, common infection. ⋯ Although the possibility of underlying endocarditis arises in virtually every patient with SAB, only a minority of bacteremic patients will actually have cardiac involvement. Distinguishing patients with S. aureus infective endocarditis (IE) from those with uncomplicated SAB is essential, but often difficult. In this review, the authors summarize recent changes in the epidemiology of SAB and IE, discuss the challenges in distinguishing SAB from IE, and discuss current trends in the management of patients with SAB and IE.
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Infect. Dis. Clin. North Am. · Dec 2001
ReviewLaboratory diagnosis of central nervous system infections.
The laboratory diagnosis of CNS infection is essential for optimal therapy. Acute infection requires rapid turn-around testing with high predictive values, that is, the ability of a test to accurately identify those patients who do or do not have disease caused by a specific etiology. The Gram's stain, fungal stains of direct smears, antigen testing for C. neoformans, and culture of bacteria, fungi, mycobacteria, and some viruses are important tests for the diagnosis of acute infection. ⋯ The appearance of new etiologies, such as West Nile virus, and the common use of PCR for the herpes viruses and enteroviruses represent important advances. Evolving methods for the laboratory diagnosis of CNS infection represent significant improvements over previous testing; however, the array of tests available demands more attention for appropriate selection, is significantly more expensive, and requires new skills for performance and interpretation. The responsibility for proper use of laboratory testing lies both with the clinician and laboratory technician.
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Advances in public health have reduced the risk of contracting certain enteric diseases, but many remain, and new pathogens have emerged and/or recently have been discovered. The pathogenic agents are varied and consist of a variety of bacteria and select viruses and parasites. ⋯ The age of the patient, time of year, travel history, and clinical presentation all provide clues to the etiologic agent. Microbiologic assays should be used judiciously to confirm or exclude the likely infectious agents.