The outcomes of thoracoscopic decortication between fungal empyema and bacterial empyema

Clinical Ramifications of Bacterial Aggregation in Pleural Fluid

Background: Bacterial aggregation has been well described to occur in synovial fluid, but it is unknown if bacteria form aggregates in body fluids beyond the synovial fluid. Consequently, this translational study evaluated the ability to form bacterial aggregates in different pleural fluids. Methods: Four of the most common causes of thoracic empyema-Streptococcus mitis, Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa-were used here. The different pleural fluids included one transudative and two exudative pleural fluids. Twenty-four-well microwell plates were used to form the aggregates with the aid of an incubating shaker at different dynamic conditions (120 RPM, 30 RPM, and static). The aggregates were then visualized with SEM and evaluated for antibiotic resistance and the ability of tissue plasminogen activator (TPA) to dissolve the aggregates. Statistical comparisons were made between the different groups. Results: Bacterial aggregates formed at high shaking speeds in all pleural fluid types, but no aggregates were seen in TSB. When a low shaking speed (30 RPM) was used, only exudative pleural fluid with a high protein content formed aggregates. No aggregates formed under static conditions. Furthermore, there was a statistical difference in the CFU/mL of bacteria present after antibiotics were administered compared to bacteria with no antibiotics (p < 0.005) and when TPA plus antibiotics were administered compared to antibiotics alone (p < 0.005). Conclusions: This study shows that bacteria can form aggregates in pleural fluid and at dynamic conditions similar to those seen in vivo with thoracic empyema. Importantly, this study provides a pathophysiological underpinning for the reason why antibiotics alone have a limited utility in treating empyema.

Thoracic empyema: aetiology, diagnosis, treatment, and prevention

PURPOSE OF REVIEW

The aim of this study was to review current key points in the aetiology, diagnosis, treatment, and prevention of empyema thoracis. Early postpandemic trends have seen an increasing global incidence and evolution in the aetiology of empyema. Due to varied aetiology and typically lengthy treatment, empyema will be disproportionately affected by the rising tide of antimicrobial resistance (AMR), thus warranting attention and further research.

RECENT FINDINGS

Multiple novel biomarkers (e.g. IL-36γ) are under investigation to aid diagnosis, while oral health assessment tools are now available for prognosticating and risk-stratifying patients with thoracic empyema. There exists an ongoing lack of evidence-based guidance surrounding antibiotic treatment duration, surgical intervention indication, and prognostic scoring utility.

SUMMARY

Understanding aetiologies in different global regions and settings is pivotal for guiding empirical treatment. Antimicrobial resistance will make thoracic empyema increasingly challenging to treat and should prompt increased awareness of prescribing practices. Novel biomarkers are under investigation which may speed up differentiation of pleural effusion types, allowing faster cohorting of patients.Although newly identified predictors of morbidity and mortality have been suggested to be beneficial for incorporation into clinical practice, further work is required to prognosticate, risk-stratify, and standardize treatment.

Culture-Positive and Culture-Negative Empyema After Thoracoscopic Decortication: A Comparison of Short-term and Long-term Outcomes

Background

Empyema thoracis is a serious infectious disease and is associated with high morbidity and mortality. The perioperative outcomes between culture-positive and culture-negative empyema after thoracoscopic decortication remained controversial, especially since there were no studies that reported the survival outcomes between culture-positive and culture-negative empyema.

Methods

This single-institute study involved a retrospective analysis. Patients with empyema thoracis who underwent thoracoscopic decortication between January 2012 and December 2021 were included in the study. Patients were grouped into a culture-positive group and a culture-negative group according to culture results obtained no later than 2 weeks after surgery.

Results

A total of 1087 patients with empyema received surgery, and 824 were enrolled after exclusion. Among these, 366 patients showed positive culture results and 458 patients showed negative results. Longer intensive care unit stays (11.69 vs 5.64 days, P < .001), longer ventilator usage (24.70 vs 14.01 days, P = .002), and longer postoperative hospital stays (40.83 vs 28.37 days, P < .001) were observed in the culture-positive group. However, there was no significant difference in 30-day mortality between the 2 groups (5.2% in culture negative vs 5.0% in culture positive, P = .913). The 2-year survival was not significantly different between the 2 groups (P = .236).

Conclusions

Patients with culture-positive or culture-negative empyema who underwent thoracoscopic decortication showed similar short-term and long-term survival outcomes. A higher risk of death was associated with advanced age, a higher Charlson Comorbidity Index score, phase III empyema, and a cause other than pneumonia.