The goal of this study is to compare the microbiologic diagnostic yield of pre-aspiration agitated pleural fluid versus that of conventionally aspirated fluid in pleural infection patients. The main question it aims to answer is, whether fluid agitation helps to increase the microbiological yield.

In pleural infection, It is suggested that the bacteria being diagnostically targeted, might more likely be residing on the pleural surface with a better blood supply and nutrition rather than being planktonic in the acidic, glucose deficient pleural fluid. The investigators thus hypothesize that an agitation of the pleural fluid prior to sample aspiration would aid in achieving a better cellular representation of the pleural space. This could have the effect of washing bacterial cells off the pleural surface as well as moving sedimented cells in the aspirated sample. This study aims to investigate whether an increase in the microbiological yield for infected pleural fluid could be achieved by a pre-aspiration agitation of the pleural fluid which would have a positive effect on management and eventual patient outcomes. Adult participants with pleural infection will undergo thoracentesis via both the standard and agitated fluid techniques guided by thoracic ultrasound. Microbiological yields will be compared.

Inclusion Criteria:

1. Age >18 years old
2. Pleural infection based on clinical presentation, imaging or laboratory investigations and pleural fluid examination showing glucose < 40 mg/dL or pH <7.2 with lower respiratory infection or pus on aspiration
3. At least a moderate amount of pleural fluid collection (2 or more intercostal spaces on thoracic ultrasound)

Exclusion Criteria:

1. Minimal - mild pleural fluid deemed unsuitable for aspiration and agitation
2. Hemodynamic instability
3. Uncorrected coagulopathy
4. Transudative or exudative lymphocytic pleural effusion on biochemical analysis

Laboratory personnel responsible for the microbiological and biochemical analysis will be blinded to the identity of the paired samples.