Pleural fluid infection caused by Dietzia cinnamea

Our plain-English summary of Pleural fluid infection caused by Dietzia cinnamea, by K.A. Cawcutt, M.M. Bhatti, D.R. Nelson (Diagnostic Microbiology and Infectious Disease, 2016).

The study

• Authors: K.A. Cawcutt, M.M. Bhatti, D.R. Nelson
• Journal: Diagnostic Microbiology and Infectious Disease
• Published: 2016;85(4):496-7
• Type of article: Case report
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Dietzia cinnamea was recovered from pleural fluid in an immunocompromised patient by inoculating blood culture bottles and was identified with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The case shows the expanding ability of microbiology laboratories to identify rare organisms through newer techniques and technology.

Copyright © 2016 Elsevier Inc. All rights reserved.

In plain English

This brief report, by authors at the Mayo Clinic in Rochester, Minnesota, described one patient. She was a 71-year-old woman receiving chemotherapy for stage IV malignant mesothelioma. She had an indwelling pleural catheter to manage persistent fluid buildup around the lung. The article does not discuss asbestos or what caused her mesothelioma. She developed two days of fever and cloudy fluid from the catheter. The laboratory put the pleural fluid into a blood culture bottle, which showed bacterial growth after 86 hours. A mass spectrometry method (MALDI-TOF) first identified the bacterium as Dietzia cinnamea, but with a low confidence score of 1.69. A special extraction method then gave a score of 2.2. Genetic sequencing showed 98.7% agreement with a reference strain of D. cinnamea. She improved on the antibiotic amoxicillin-clavulanate, and later pleural fluid cultures were negative. The authors called this the first reported human infection by this organism, though they could not definitively prove it caused the infection. They concluded the case shows the organism's capacity to cause illness in immunocompromised patients.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report (brief report) of a single patient
• Who was studied: One 71-year-old woman undergoing chemotherapy for stage IV malignant mesothelioma. She had an indwelling pleural catheter for persistent pleural effusions and had been diagnosed with mesothelioma 11 months earlier. The authors were at the Mayo Clinic, Rochester, Minnesota.
• Exposure: No asbestos exposure is described. The report concerns infection of the pleural fluid by the bacterium Dietzia cinnamea. The authors considered her indwelling pleural catheter the likely entry route.
• Main results:
  • The patient presented with 2 days of fevers (38.4°C or higher) and cloudy pleural fluid from her catheter.
  • Pleural fluid inoculated into a blood culture bottle signaled bacterial growth at 86 hours of incubation. The fluid's Gram stain had been negative for organisms.
  • MALDI-TOF mass spectrometry at 96 hours identified the organism as D. cinnamea with a low confidence score (1.69).
  • A laboratory-developed extraction protocol gave an identification of D. cinnamea with an appropriate confidence score (2.2) against the type strain.
  • 16S ribosomal sequencing showed the highest agreement (98.7%) with the D. cinnamea type strain.
  • The patient improved on amoxicillin-clavulanate, and later pleural fluid cultures were negative. Antimicrobial susceptibility testing was not performed.
• The authors' conclusion: The authors concluded that, although the organism's full infectious potential remains unclear, the case demonstrates that D. cinnamea can cause illness in immunocompromised patients. They also concluded that newer technology such as MALDI-TOF MS will allow more accurate identification of organisms.
• Limitations the authors state:
  • The authors stated they cannot definitively prove that D. cinnamea caused the pleural fluid infection.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma, Pleural plaques and thickening.

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