Severe community-acquired adenovirus pneumonia in an immunocompetent 44-year-old woman: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>This case report describes a rare condition: community-acquired adenovirus pneumonia in an immunocompetent adult. The diagnosis was achieved by using a multiplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay and highlights the usefulness of these novel molecular diagnostic techniques in patients hospitalized with acute respiratory illness. We also performed a literature search for previously published cases and present a summary of the clinical, laboratory and radiological features of this condition.</p> <p>Case presentation</p> <p>A 44-year-old immunocompetent Caucasian woman was admitted to our hospital with an acute febrile respiratory illness associated with a rash. Her blood tests were non-specifically abnormal, and tests for bacterial pathogens were negative. Her condition rapidly deteriorated while she was in our hospital and required mechanical ventilation and inotropic support. A multiplex real-time RT-PCR assay performed on respiratory specimens to detect respiratory viruses was negative for influenza but positive for adenovirus DNA. The patient recovered on supportive treatment, and antibiotics were stopped after 5 days.</p> <p>Conclusions</p> <p>Community-acquired adenovirus pneumonia in immunocompetent adult civilians presents as a non-specific acute febrile respiratory illness followed by the abrupt onset of respiratory failure, often requiring mechanical ventilation. Its laboratory and radiological features are typical of viral infections but also are non-specific. Novel multiplex real-time RT-PCR testing for respiratory viruses enabled us to rapidly make the diagnosis in this case. The new technology could be used more widely in patients with acute respiratory illness and has potential utility for rationalization of the use of antibiotics and improving infection control measures.</p

Using experimental evolution to explore natural patterns between bacterial motility and resistance to bacteriophages

Resistance of bacteria to phages may be gained by alteration of surface proteins to which phages bind, a mechanism that is likely to be costly as these molecules typically have critical functions such as movement or nutrient uptake. To address this potential trade-off, we combine a systematic study of natural bacteria and phage populations with an experimental evolution approach. We compare motility, growth rate and susceptibility to local phages for 80 bacteria isolated from horse chestnut leaves and, contrary to expectation, find no negative association between resistance to phages and bacterial motility or growth rate. However, because correlational patterns (and their absence) are open to numerous interpretations, we test for any causal association between resistance to phages and bacterial motility using experimental evolution of a subset of bacteria in both the presence and absence of naturally associated phages. Again, we find no clear link between the acquisition of resistance and bacterial motility, suggesting that for these natural bacterial populations, phage-mediated selection is unlikely to shape bacterial motility, a key fitness trait for many bacteria in the phyllosphere. The agreement between the observed natural pattern and the experimental evolution results presented here demonstrates the power of this combined approach for testing evolutionary trade-offs