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Purifying the Impure: Sequencing Metagenomes and Metatranscriptomes from Complex Animal-associated Samples
Published on: December 22, 2014
Detection of Chlamydia psittaci in both blood and bronchoalveolar lavage fluid using metagenomic next-generation
Yingpu Yuan1, Xiaobo Zhang2, Chunmei Gui1
1Department of Critical Care Medicine.
Rationale:
Chlamydia psittaci (C psittaci) is a gram-negative obligate intracellular parasite, with birds as main hosts. The main route of infection in humans is inhalation of aerosols from contaminated animal excreta through the respiratory tract. The main manifestation of C psittaci infection is pneumonia. Patients suffering from severe infection are prone to sepsis and multiple organ failure. We report a case of simultaneous detection of C psittaci in blood and bronchoalveolar lavage fluid using metagenomic next-generation sequencing (mNGS) technology.
Patient Concerns:
The 71-year-old male patient was a farmer with a long history of raising poultry and initial symptoms of fever and muscle pain accompanied by limb weakness and paroxysmal cough.
Diagnoses:
The patient was diagnosed with sepsis, severe pneumonia, and multiple organ failure.
Interventions:
Anti-infective therapy with doxycycline and meropenem was applied.
Outcomes:
The patient's body temperature and infection indicators improved and the chest X-ray findings showed the amelioration of lesions after 18 days of treatment. The patient was discharged without treatment on hospital day 19 due to financial constraints and subsequently died after 7 days.
Lessons:
mNGS is an excellent diagnostic tool when specific pathogens are undetected by traditional assays.
Insights
Metagenomic next-generation sequencing (mNGS) successfully detected Chlamydia psittaci in a farmer with severe pneumonia and sepsis. This advanced diagnostic tool is crucial when traditional methods fail to identify specific pathogens.
Area of Science:
- Infectious Diseases
- Microbiology
- Genomics
Background:
- Chlamydia psittaci (C psittaci), an avian-associated bacterium, causes psittacosis, primarily manifesting as pneumonia in humans.
- Human infection typically occurs via inhalation of contaminated aerosols, potentially leading to severe illness including sepsis and organ failure.
Observation:
- A 71-year-old male farmer presented with fever, myalgia, weakness, and cough, indicative of a severe respiratory infection.
- The patient developed sepsis, severe pneumonia, and multiple organ failure, necessitating intensive treatment.
Findings:
- Simultaneous detection of C psittaci in both blood and bronchoalveolar lavage fluid was achieved using metagenomic next-generation sequencing (mNGS).
- Treatment with doxycycline and meropenem led to clinical improvement, with resolution of fever and radiographic lesions.
Implications:
- mNGS offers a powerful diagnostic approach for identifying challenging pathogens like C psittaci, especially when conventional tests are inconclusive.
- This case highlights the utility of mNGS in diagnosing severe infections and guiding appropriate anti-infective therapy.
