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Published on: February 23, 2014
Fastidious intracellular bacteria as causal agents of community-acquired pneumonia
Frédéric Lamoth1, Gilbert Greub
1Infectious Diseases Service, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
Abstract:
Intracellular bacteria are common causes of community-acquired pneumonia that grow poorly or not at all on standard culture media and do not respond to beta-lactam antibiotic therapy. Apart from well-established agents of pneumonia such as Legionella pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci and Coxiella burnetii, some new emerging pathogens have recently been recognized, mainly Parachlamydia acanthamoebae and Simkania negevensis, two Chlamydia-related bacteria. Most of them are causes of benign and self-limited infections. However, they may cause severe pneumonia in some cases (i.e., Legionnaires' disease) and they may cause outbreaks representing a public health problem deserving prompt recognition and appropriate therapy. Although extrapulmonary manifestations are often present, no clinical features allow them to be distinguished from classical bacterial agents of pneumonia such as Streptococcus pneumoniae. Thus, specific molecular diagnostic tools are very helpful for early recognition of the offending bacteria, whereas serology often only allows retrospective or late diagnosis. Macrolides remain the best empirical treatment of intracellular respiratory pathogens, although some observational studies suggest that quinolones may be superior for the treatment of legionellosis.
Insights
Intracellular bacteria cause community-acquired pneumonia and are difficult to culture. Molecular diagnostics and macrolide or quinolone antibiotics are key for recognizing and treating these challenging respiratory pathogens.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Pulmonary Medicine
Background:
- Intracellular bacteria are significant causes of community-acquired pneumonia.
- These pathogens often resist standard culture and beta-lactam antibiotics.
- Emerging intracellular pathogens like Parachlamydia acanthamoebae and Simkania negevensis are increasingly recognized.
Purpose of the Study:
- To highlight the diagnostic and therapeutic challenges posed by intracellular bacterial pneumonia.
- To emphasize the importance of molecular diagnostics for early pathogen identification.
- To discuss current and potential treatment strategies for these infections.
Main Methods:
- Review of established and emerging intracellular bacterial pathogens causing pneumonia.
- Discussion of diagnostic limitations of conventional culture methods.
- Analysis of clinical features and treatment outcomes.
Main Results:
- Intracellular bacterial pneumonia can range from self-limited to severe, including outbreaks.
- Clinical presentation often mimics pneumonia caused by classical bacteria, necessitating specific diagnostics.
- Molecular tools offer rapid and accurate identification, while serology is often retrospective.
Conclusions:
- Early recognition of intracellular bacterial pneumonia is crucial for effective management.
- Molecular diagnostics are superior to serology for timely diagnosis.
- Macrolides are the recommended empirical treatment, with quinolones showing promise for Legionnaires' disease.
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