Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Feb 2009
ReviewDiagnostic strategies for healthcare-associated pneumonia.
The first point of a good diagnostic strategy for healthcare-associated pneumonia (HCAP) is correct classification of patients with specific criteria, as suggested by the last American Thoracic Society/ Infectious Diseases Society of America (ATS/IDSA) guidelines. However, clinical practice and recent literature have suggested new risk factors for multidrug-resistant infection (MRI): the presence of permanent indwelling devices, prior antibiotic use in the last 3 months, chronic and advanced pulmonary diseases (chronic obstructive pulmonary disease, bronchiectasis, etc.), history of alcoholism, and immunosuppression. The clinical presentation in HCAP patients is often unusual (mild respiratory symptoms and frequent extrapulmonary manifestations) due to different factors: advanced age, neurological disorders, and multiple chronic comorbidities. ⋯ The clinical use of new biomarkers of infection and sepsis (procalcitonin, etc.) is currently being investigated. Extensive microbiological testing to overcome the high prevalence of MRI in HCAP, including urinary antigens for Legionella and Streptococcus pneumoniae; blood cultures; Gram staining and low respiratory tract secretions (sputum, tracheobronchial aspirate, fibrobronchial aspirate, protected specimen brush, bronchoalveolar lavage); and cultures for aerobic, anaerobic, mycobacterial, and fungal pathogens are recommended, whereas the indication for serology tests for respiratory viruses and atypical pathogens is low. By contrast, the new polymerase chain reaction-based techniques for the rapid identification (2 to 4 hours) of microbial pathogens in respiratory samples (nasopharyngeal swab, bronchoalveolar lavage) seem to be the most innovative future perspective in the diagnostics of HCAP.
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Atypical pneumonia was first described in 1938, and over time, Mycoplasma, Legionella, and Chlamydophila were the agents commonly linked with community-associated atypical pneumonia. However, as technology has improved, so has our understanding of this clinical entity. It is now known that there are many agents linked with atypical pneumonia in the community, and many of these agents are also major causes of healthcare-associated pneumonia. ⋯ Bacterial agents include Legionella species, Mycoplasma pneumoniae, Chlamydophila species, and Coxiella burnetii. Although there are over 100 viruses that can cause respiratory tract infections, only a fraction of those have been defined in the context of healthcare-associated atypical pneumonia: adenovirus and human bocavirus (HBoV); rhinovirus; human coronaviruses (HCoV), including HCoV 229E, HCoV OC43, HCoV NL63, HCoV HKU1; members of the paramyxoviridae (parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus); hantavirus; influenza; and severe acute respiratory syndrome (SARS) Co-V. Our knowledge about healthcare-associated atypical pneumonia will continue to evolve as newer pathogens are identified and as newer diagnostic modalities such as multiplex polymerase chain reaction are introduced.
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Semin Respir Crit Care Med · Feb 2009
ReviewThe role of gram-negative bacteria in healthcare-associated pneumonia.
Healthcare-associated pneumonia (HCAP) is a unique entity that differs from community-acquired pneumonia in both bacteriology and outcomes and has similarities to hospital-acquired pneumonia and ventilator-associated pneumonia. HCAP patients are at higher risk of potential multidrug-resistant pathogens, including resistant gram-negative organisms, especially Pseudomonas aeruginosa and acinetobacter spp., but also extended-spectrum beta-lactamases (ESBLs). This manuscript reviews the epidemiology, etiology, and clinical outcomes of hospitalized HCAP patients due to gram-negative bacteria. We will focus our attention on the potential multidrug-resistant pathogens to suggest a new treatment approach for these patients.
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Current antibiotics available for the treatment of healthcare-associated pneumonia (HCAP) may result in clinical failure due to resistance development, side effect intolerance, or poor pharmacokinetic-pharmacodynamic profiles. New agents active against common HCAP pathogens are needed. The mechanism of action, spectrum of activity, pharmacokinetics, adverse effects, and clinical efficacy of seven new agents in clinical development or recently approved with either methicillin-resistant Staphylococcus aureus (MRSA) or pseudomonal activity are reviewed. They include doripenem, a new antipseudomonal carbapenem; ceftobiprole and ceftaroline, two anti-MRSA cephalosporins; iclaprim, a selective dihydrofolate reductase antagonist; and three glycopeptides, dalbavancin, telavancin, and oritavancin.
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Semin Respir Crit Care Med · Feb 2009
ReviewHealthcare-associated pneumonia in the emergency department.
Emergency medicine clinicians frequently diagnose and treat patients with pneumonia. The recent recognition of healthcare-associated pneumonia (HCAP) mandates that emergency medicine clinicians remain current and able to distinguish this from community-acquired pneumonia. This article reviews the diagnosis and management of HCAP from the perspective of the emergency medicine clinician.