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Published on: May 21, 2015
Identification of bacterial DNA in noninfectious pleural fluid with a highly sensitive PCR method
Rosa Cremades1, Antonio Galiana, Juan Carlos Rodriguez
1Section of Microbiology, Hospital General Universitario, Elche, Spain.
Background:
Bacterial DNA due to bacterial translocation has been identified in noninfectious ascitic fluid samples.
Objective:
This study investigated the possible presence of bacterial DNA in the pleural fluid of patients with pleural effusions of noninfectious origin, using a highly sensitive PCR-based method.
Methods:
Pleural fluid samples from 175 patients (average age ± SD: 69 ± 14 years) with noninfectious pleural effusion (62 transudates, 113 exudates) were analyzed. Bacterial DNA was detected using nested PCR with amplification of a fragment of the gene r16S, with 2 amplification protocols, i.e. low sensitivity (10 and 40 cycles) and high sensitivity (40 and 40 cycles).
Results:
With the less sensitive amplification process, only 1 sample was positive (Haemophilus parainfluenzae in a patient with hepatic hydrothorax). With the highly sensitive nested PCR method, bacterial DNA was identified in the pleural fluid, of both transudative and exudative origin, of 75 of the 175 patients (43%). In cases of isolation of a single bacterium, the more frequent were Escherichia coli, Salmonella enterica and Streptococcus pneumoniae.
Conclusions:
Regardless of its origin, bacterial DNA can be identified in almost half of noninfectious pleural effusions by using a highly sensitive PCR-based method. The possible clinical significance or prognostic value of these findings deserves to be evaluated.
Insights
Bacterial DNA was detected in nearly half of noninfectious pleural effusions using a sensitive PCR method. This finding in pleural fluid warrants further investigation into its clinical significance.
Area of Science:
- Medical Microbiology
- Pulmonary Medicine
- Molecular Diagnostics
Background:
- Bacterial DNA has been previously found in noninfectious ascitic fluid, suggesting bacterial translocation.
- The presence of bacterial DNA in pleural effusions of noninfectious origin remains largely uninvestigated.
Purpose of the Study:
- To investigate the presence of bacterial DNA in pleural fluid from patients with noninfectious pleural effusions.
- To utilize a highly sensitive polymerase chain reaction (PCR)-based method for bacterial DNA detection.
Main Methods:
- Analysis of pleural fluid samples from 175 patients with noninfectious pleural effusion (62 transudates, 113 exudates).
- Detection of bacterial DNA using nested PCR targeting the 16S rRNA gene with varying amplification cycles (low and high sensitivity protocols).
Main Results:
- A low-sensitivity PCR detected bacterial DNA in only one sample.
- The highly sensitive nested PCR identified bacterial DNA in 75 out of 175 patients (43%) with noninfectious pleural effusions.
- Commonly identified bacteria included Escherichia coli, Salmonella enterica, and Streptococcus pneumoniae.
Conclusions:
- Bacterial DNA is detectable in almost half of noninfectious pleural effusions using a sensitive PCR method, irrespective of effusion type.
- The clinical significance and prognostic value of detecting bacterial DNA in these effusions require further evaluation.
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