Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Feb 2015
ReviewTreatment of Methicillin-Resistant Staphylococcus aureus: Vancomycin and Beyond.
There has been a welcome increase in the number of agents available for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin remains an acceptable treatment option, with moves toward individualized dosing to a pharmacokinetic/pharmacodynamic (PK/PD) target. Numerous practicalities, however, would need to be resolved before implementation. ⋯ Whether these strengths and features are agent or class specific are unclear but will likely be answered with the marketing of tedizolid. There are insufficient data to recommend either quinupristin/dalfopristin or tigecycline, as first line in the treatment of severe MRSA infections. These agents however remain options in patients with no other alternatives.
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Semin Respir Crit Care Med · Feb 2015
ReviewColistin: How should It Be Dosed for the Critically Ill?
Colistin, an "old" polymyxin antibiotic, is increasingly being used as last-line treatment against infections caused by multidrug-resistant gram-negative bacteria. It is administered in patients, parenterally or by inhalation, as its inactive prodrug colistin methanesulfonate (CMS). Scientifically based recommendations on how to optimally dose colistin in critically ill patients have become available over the last decade and are extremely important as colistin has a narrow therapeutic window. ⋯ Inhalation of CMS achieves considerably higher colistin concentrations in lung fluids than is possible with intravenous administration, with negligible plasma exposure. Similarly, for central nervous system infections, dosing CMS directly into the cerebrospinal fluid generates significantly higher colistin concentrations at the infection site compared with what can be achieved with systemic administration. While questions remain to be addressed via ongoing research, this article reviews the significant advances that have been made toward optimizing the clinical use of colistin.
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Semin Respir Crit Care Med · Feb 2015
ReviewAcinetobacter baumannii: Evolution of Antimicrobial Resistance-Treatment Options.
The first decade of the 20th century witnessed a surge in the incidence of infections due to several highly antimicrobial-resistant bacteria in hospitals worldwide. Acinetobacter baumannii is one such organism that turned from an occasional respiratory pathogen into a major nosocomial pathogen. An increasing number of A. baumannii genome sequences have broadened our understanding of the genetic makeup of these bacteria and highlighted the extent of horizontal transfer of DNA. ⋯ Treatment of carbapenem-resistant A. baumannii infection therefore involves the use of combinations of last resort agents such as colistin and tigecycline, but the efficacy and safety of these approaches are yet to be defined. Antimicrobial-resistant A. baumannii has high potential to spread among ill patients in intensive care units. Early recognition and timely implementation of appropriate infection control measures is crucial in preventing outbreaks.
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Semin Respir Crit Care Med · Feb 2015
ReviewClinical Management of Infections Caused by Enterobacteriaceae that Express Extended-Spectrum β-Lactamase and AmpC Enzymes.
The production of β-lactamase is the principal mechanism by which gram-negative bacteria resist the action of β-lactam antibiotics. In recent decades, there has been an alarming explosion in the diversity, global dissemination, host range, and spectrum of activity of β-lactamases. This has been most clearly reflected by the marked increase in infections caused by bacteria that express extended-spectrum β-lactamases (ESBLs). ⋯ Recently, high-level AmpC production has also been seen in new species such as Escherichia coli via plasmid acquisition. ESBL and AmpC producers present challenges to susceptibility testing and the selection of appropriate antimicrobial therapy. This review describes the current global epidemiology of ESBL producers, examines reported risk factors for infections caused by gram-negative bacteria that express ESBL or AmpC enzymes, and discusses the options for antimicrobial therapy, including "re-discovered" older antibiotics and novel agents in development.
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Semin Respir Crit Care Med · Feb 2015
ReviewDiagnosis and Management of Clostridium difficile Infection.
There have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease, attributed to the emergence of a fluoroquinolone-resistant "hypervirulent" strain, ribotype 027. C. difficile is now the most common pathogen causing hospital-acquired infection in U. S. hospitals, and community-acquired infections are increasing. ⋯ Management of severe CDI and recurrent CDI continue to represent major treatment challenges. Biological therapies for the restoration of the intestinal microbiota (e.g., fecal microbiota transplantation) and monoclonal antibody therapy are promising approaches for CDI management, in particular troublesome recurrent CDI. This review will concentrate on the diagnosis and management of CDI in adults.