Bacteriology and clinical outcomes of patients with culture-positive pleural infection in Western Australia: A 6-year analysis

Clinical characteristics of community-acquired primary pleural infection compared to postpneumonic pleural infection: a retrospective study

BACKGROUND

Data on the clinical features and treatment outcomes in patients with primary pleural infection (PI) are limited. This study aimed to investigate the clinical characteristics of these patients.

PATIENTS AND METHODS

In this retrospective study, patients with community-acquired PI, diagnosed based on pleural fluid analysis, were classified into postpneumonic and primary PI groups according to computed tomography (CT) findings. Clinical variables, microbiological data, and CT findings were compared between the two groups.

RESULTS

Approximately 28 % of patients with community-acquired PI presented as primary PI. Treatment success rates and in-hospital or 30-day mortality were comparable between the two groups. However, compared to the postpneumonic PI group, the primary PI group was significantly younger and had lower proportions of patients with Pneumonia Severity Index classes 4-5 and RAPID (Renal, Age, Purulence, Infection source, and Dietary factors) score >3. On CT scans, subpleural abscesses were present in less than half of the patients in the primary PI group, compared to most patients in the postpneumonic PI group. Pleural enhancement and extrapleural fat proliferation were more frequently observed in patients with primary PI than in those with postpneumonic PI. In the primary PI group, Streptococcus anginosus group was the most common pathogen, accounting for nearly half of the causative organisms.

CONCLUSIONS

Patients with primary PI had similar treatment outcomes compared to those with postpneumonic PI. However, different causative pathogens and radiologic findings of primary PI suggest a distinct pathogenesis of PI independent of pneumonia.

Impact of a specialised pleural medicine unit in the management of pleural infection

BACKGROUND

Managing pleural infection can be complex and costly and demonstrates considerable healthcare utlilisation.

AIMS

To describe the influence of a specialised pleural medicine unit (SPMU) on outcomes for people with pleural infection at a metropolitan health service.

METHODS

Administrative data were used to identify cases of pleural infection, which were classified into (i) empyema, (ii) parapneumonic effusion and (iii) clinical suspicion of pleural infection. Two cohorts were compared: Period 1 (pre-SPMU from January 2016 to August 2018) and Period2 (post-SPMU from August 2018 to October 2020).

RESULTS

In total, 213 individuals were managed for pleural infection across the two time periods (Period 1 (n = 108), Period 2 (n = 105)). Intrapleural therapy (IPT) was utilised more frequently in Period 2 (0% vs 15.2%, P = <0,001) with earlier intervention (76.8 vs 47.5 h, P = 0.17). These observations were associated with a significant reduction in surgical intervention rate (25.9% vs 7.6%, P < 0.001) without any significant difference in the median length of stay from diagnosis to discharge (9.4 days (interquartile range (IQR) 5.1-15.9) days in Period 1 vs 7.3 days (IQR 4.3-13.1 days) in Period 2 (P = 0.13)). Outcomes at 90 days (mortality and pleural-related readmissions) were not different between the two cohorts. In a subgroup analysis comparing patients who received advanced therapies (either surgery or IPT), there was shorter hospitalisation time (15.8 vs 12.5 days, P = 0.084) and lower inpatient costs ($79 663.9 vs $56 513.6, P = 0.016) during Period 2 without a rise in adverse events or mortality.

CONCLUSION

The introduction of an SPMU was associated with increased utilisation of IPT and a reduction in surgical interventions for the management of pleural infections.

Pleural Infection: Diagnosis, Management, and Future Directions

Pleural infection represents a significant and ongoing challenge for patients, clinicians, and healthcare providers given the morbidity and mortality associated with this condition. Whilst our understanding of how pleural infection develops and how it should be treated has improved considerably over the past couple of decades, this has yet to translate into a meaningful positive impact on key outcomes. Making the diagnosis of pleural infection is not always straightforward, and the long-standing belief that it always occurs as a complication of lung parenchymal infection is being increasingly recognised as incorrect. Identifying the causative organism(s) is equally uncertain, with almost half of cases of pleural infection proving to be culture negative using traditional methods. Whilst we are now able to determine which patients are more likely to have a poor outcome from their pleural infection at the time of diagnosis, how this should affect their treatment pathway-including the role of more invasive strategies such as surgery or intrapleural enzyme therapy-is not yet known. This review article aims to summarise the existing evidence base and best clinical practice for the non-specialist, whilst highlighting recent research which has or will change the way we manage pleural infection, as well as those areas where further studies are still needed.

Prognostic significance of pleural fluid microbiological positivity in pleural infection: a bicentric 10-year retrospective observational study

BACKGROUND

Despite its heterogeneity, there is currently limited data in pleural infection phenotyping. Using pleural fluid characteristics, pleural infection can be classified into microbiological-positive pleural infection (MPPI) and microbiological-negative pleural infection (MNPI). This study aimed to evaluate the prognostic significance of microbiological positivity in pleural infection, and to evaluate the performance of RAPID (renal, age, purulence, infection source, dietary factor) score in these subgroups.

METHODS

Consecutive patients hospitalized for pleural infection over a 10-year period in two acute-care hospitals in Hong Kong were evaluated. According to the pleural fluid characteristics, they were classified into MPPI and MNPI, respectively. Survival was evaluated using multivariate Cox regression analysis. Performance of RAPID score to predict mortality at 3-month and 1-year was evaluated using C-statistics.

RESULTS

In total, 381 patients with pleural infection were included. They were classified into MPPI (n = 169) and MNPI (n = 212), respectively. The MPPI group had more elderly home residence and use of large-bore chest tube, and higher Charlson comorbidity index and RAPID score, compared to the MNPI group. Length-of-stay, the need of surgery and intensive care were similar between the two groups. MPPI was associated with significantly increased risk of mortality (adjusted hazard ratio [aHR] 1.46, 95% CI 1.08-1.98). Three-month mortality was significantly higher in MPPI compared to MNPI (24.9% vs. 10.4%, p < 0.001; adjusted odd ratio 2.05, 95% CI 1.11-3.80). The trend continued at 1, 3, 5 and 7 years. RAPID score predicted 3-month and 1-year mortality in both groups (C-statistics, MPPI 0.71, 0.75; MNPI 0.84, 0.81). In the MPPI group, presence of Staphylococcus aureus (aHR 2.26, 95% CI 1.43-3.57) and Gram-negative organisms other than Enterobacteriaceae (aHR 2.00, 95% CI 1.10-3.61) were associated with worse survival, while presence of Streptococcus anginosus group was associated better survival (aHR 0.50, 95% CI 0.32-0.78), when compared to their absence.

CONCLUSIONS

Pleural fluid microbiological positivity is independently associated with increased mortality in patients with pleural infections. This finding should complement the RAPID score in risk stratification and inform future research aimed at improving outcomes in this patient population.

Evaluating the feasibility, sensitivity, and specificity of next-generation molecular methods for pleural infection diagnosis

Pleural infections are common and associated with substantial healthcare costs, morbidity, and mortality. Accurate diagnosis remains challenging due to low culture positivity rates, frequent polymicrobial involvement, and non-specific diagnostic biomarkers. Here, we undertook a prospective study examining the feasibility and performance of molecular methods for diagnosing suspected pleural infection. We prospectively characterized 26 consecutive clinically suspected pleural infections, and 10 consecutive patients with suspected non-infective pleural effusions, using shotgun metagenomics, bacterial metataxonomics, quantitative PCR, and conventional culture. Molecular methods exhibited excellent diagnostic performance, with each method identifying 54% (14 out of 26) positive cases among the pleural infection cohort, versus 38% (10 out of 26) with culture. Metagenomics and bacterial metataxonomics unveiled complex polymicrobial infections that were not captured by culture. Dominant microbes included streptococci (Streptococcus intermedius, Streptococcus pyogenes, and Streptococcus mitis), Prevotella spp. (Prevotella oris and Prevotella pleuritidis), staphylococci (S. aureus and S. saprophyticus), and Klebsiella pneumoniae. However, we encountered challenges that complicated pleural infection interpretation, including: (i) uncertainties regarding microbial pathogenicity and the impact of prior antibiotic therapy on diagnostic performance; (ii) lack of a clinical diagnostic gold-standard for molecular performance comparisons; (iii) potential microbial contamination during specimen collection or processing; and (iv) difficulties distinguishing background microbial noise from true microbial signal in low-biomass specimens. This pilot study demonstrates the potential utility and value of molecular methods in diagnosing pleural infection and highlights key concepts and challenges that should be addressed when designing larger prospective trials.IMPORTANCEConfident pleural infection diagnosis is often challenging due to low culture positivity rates, frequent polymicrobial involvement, and non-specific diagnostic biomarkers. Limitations of conventional diagnostic tests result in prolonged and inappropriately broad-spectrum antimicrobial use, encouraging antimicrobial resistance and leading to avoidable adverse effects. Here, we demonstrate the feasibility, utility, and challenges associated with the use of culture-independent molecular techniques for accurate pleural infection diagnosis in a real-world clinical setting. These data will help to inform the design of larger prospective clinical trials and identify potential obstacles to be overcome before next-generation sequencing technologies can be integrated into routine clinical practice.

Intrapleural fibrinolytic therapy for pleural infections: Outcomes from a cohort study

Introduction

Pleural infections are a significant cause of mortality. Intrapleural fibrinolytic therapy (IPFT) utilising alteplase and dornase is a treatment option for patients unsuitable for surgery. The optimal dose of alteplase is unknown, and factors affecting treatment success in an Asian population are unclear. We sought to determine the factors affecting treatment success in Tan Tock Seng Hospital, Singapore and evaluate the efficacy of lower doses of IPFT.

Method

A retrospective analysis of patients with pleural infections treated with IPFT between July 2016 and November 2023 was performed. Treatment success was defined as survival without surgery at 3 months. Data, including patient demographics; comorbidities; RAPID (renal, age, purulence, infection source and dietary factor) scores; and radiological characteristics, were extracted from medical records and analysed. Linear mixed effects model and logistic regression were performed to determine factors affecting treatment success.

Results

A total of 131 cases were analysed. Of these, 51 (38.9%) reported positive pleural fluid culture, and the most common organism was Streptoccocus anginosus. Mean age was 65 years (standard deviation [SD] 15.5). Mean time from chest tube insertion to first dose of IPFT was 10.2 days (SD 11.5). Median starting dose of alteplase was 5 mg. Treatment success was reported in 112 cases (85.5%). There were no significant differences between the alteplase dose and radiological clearance. Patient age (odds ratio [OR] 0.94, confidence interval [CI] 0.89-0.98) and interval between chest tube insertion to first dose (OR 0.95, CI 0.91-0.99) were statistically significant variables for the treatment success.

Conclusion

Lower starting doses of alteplase remain effective in the treatment of pleural infection. Early IPFT may result in better outcomes.

Empyema Caused by Mixed Infection with Streptococcus intermedius and Streptococcus constellatus in a Patient with Previous Surgery for Oral Carcinoma: A Case Report

Background

The incidence of community-acquired empyema caused by the Streptococcus anginosus group (SAG) has been on the rise in the 2020s. To the best of our knowledge, while empyema caused individually by either strain has been reported, there are no reports on empyema caused by concurrent infection with these two strains. Here, we report for the first time empyema caused by concurrent infection with Streptococcus intermedius and Streptococcus constellatus (both SAG species) in a postoperative patient who had been treated for floor of the mouth carcinoma.

Case Presentation

A 61-year-old male patient who had undergone surgical treatment for floor of the mouth carcinoma 2 year earlier suddenly presented with left-sided chest pain. Chest computed tomography (CT) revealed encapsulated pleural effusion on the left side, which was diagnosed as empyema. Metagenomic next-generation sequencing(mNGS) of the pleural fluid sample indicated mixed infection caused by Streptococcus intermedius and Streptococcus constellatus. The patient's condition improved about 5 weeks after treatment with thoracic fluid drainage and cephalosporin antibiotics.

Conclusion

This case highlights the possibility of concurrent infection with two SAG strains in patients with empyema. Currently, it is unclear whether there is a definitive relationship between a surgical history of carcinoma of the floor of the mouth and empyema caused by infection with SAG strains. This case could, perhaps, serve as a reference for future related research on the topic.

Seasonal variations of empyema in Taiwan: A 10-year analysis

BACKGROUND

Empyema is a serious infection in pleural space. Finding out seasonal variations of empyema and its pathogens can help in providing preventive measures, and implicating future researches.

METHODS

This study is a 10-year observational study in a single center. Patients with empyema thoracis receiving thoracoscopic decortication between January 2012 and December 2021 were included in the study.

RESULTS

There were 1082 empyema patients enrolled in this study. No seasonal variation was noted (spring = 25.7 %, summer =25.5 %, autumn = 24.8 %, winter = 24.0 %). However, we observed seasonal variations in pathogens. Streptococcus species had slightly higher prevalence in winter and spring than summer and autumn (54.3 % vs. 45.7 %) without significant difference (p = 0.251). On the contrary, Staphylococcus species occurred more often in summer and autumn than winter and spring (61.5 % vs. 38.5 %) (p = 0.035). Klebsiella species were more likely found in autumn (34.9 %) (p = 0.050), and Pseudomonas species showed no peak prevalence in any season (p = 0.423). The incidence of Streptococcus species increased over the years.

CONCLUSIONS

Although no seasonal variation was found in severe empyema patients requiring surgery, there were seasonal variations for the pathogens in Taiwan. The medical community should focus on Streptococcus species in winter and spring and Staphylococcus species in summer and autumn.

Infective Pleural Effusions-A Comprehensive Narrative Review Article

Infective pleural effusions are mainly represented by parapneumonic effusions and empyema. These conditions are a spectrum of pleural diseases that are commonly encountered and carry significant mortality and morbidity rates reaching upwards of 50%. The causative etiology is usually an underlying bacterial pneumonia with the subsequent seeding of the infectious culprit and inflammatory agents to the pleural space leading to an inflammatory response and fibrin deposition. Radiographical evaluation through a CT scan or ultrasound yields high specificity and sensitivity, with features such as septations or pleural thickening indicating worse outcomes. Although microbiological yields from pleural studies are around 56% only, fluid analysis assists in both diagnosis and prognosis by evaluating pH, glucose, and other biomarkers such as lactate dehydrogenase. Management centers around antibiotic therapy for 2-6 weeks and the drainage of the infected pleural space when the effusion is complicated through tube thoracostomies or surgical intervention. Intrapleural enzymatic therapy, used to increase drainage, significantly decreases treatment failure rates, length of hospital stay, and surgical referrals but carries a risk of pleural hemorrhage. This comprehensive review article aims to define and delineate the progression of parapneumonic effusions and empyema as well as discuss pathophysiology, diagnostic, and treatment modalities with aims of broadening the generalist's understanding of such complex disease by reviewing the most recent and relevant high-quality evidence.

Outcomes of Pleural Space Infections in Patients With Indwelling Pleural Catheters for Active Malignancies

BACKGROUND

Pleural infections related to indwelling pleural catheters (IPCs) are an uncommon clinical problem. However, management decisions can be complex for patients with active malignancies due to their comorbidities and limited life expectancies. There are limited studies on the management of IPC-related infections, including whether to remove the IPC or use intrapleural fibrinolytics.

METHODS

We conducted a retrospective cohort study of patients with active malignancies and IPC-related empyemas at our institution between January 1, 2005 and May 31, 2021. The primary outcome was to evaluate clinical outcomes in patients with malignant pleural effusions and IPC-related empyemas treated with intrapleural tissue plasminogen activator (tPA) and deoxyribonuclease (DNase) compared with those treated with tPA alone or no intrapleural fibrinolytic therapy. The secondary outcome evaluated was the incidence of bleeding complications.

RESULTS

We identified 69 patients with a malignant pleural effusion and an IPC-related empyema. Twenty patients received tPA/DNase, 9 received tPA alone, and 40 were managed without fibrinolytics. Those treated with fibrinolytics were more likely to have their IPCs removed as part of the initial management strategy ( P =0.004). The rate of surgical intervention and mortality attributable to the empyema were not significantly different between treatment groups. There were no bleeding events in any group.

CONCLUSION

In patients with IPC-related empyemas, we did not find significant differences in the rates of surgical intervention, empyema-related mortality, or bleeding complications in those treated with intrapleural tPA/DNase, tPA alone, or no fibrinolytics. More patients who received intrapleural fibrinolytics had their IPCs removed, which may have been due to selection bias.

Diagnosis and management of pleural infection

Pleural infection remains a medical challenge. Although closed tube drainage revolutionised treatment in the 19th century, pleural infection still poses a significant health burden with increasing incidence. Diagnosis presents challenges due to non-specific clinical presenting features. Imaging techniques such as chest radiographs, thoracic ultrasound and computed tomography scans aid diagnosis. Pleural fluid analysis, the gold standard, involves assessing gross appearance, biochemical markers and microbiology. Novel biomarkers such as suPAR (soluble urokinase plasminogen activator receptor) and PAI-1 (plasminogen activator inhibitor-1) show promise in diagnosis and prognosis, and microbiology demonstrates complex microbial diversity and is associated with outcomes. The management of pleural infection involves antibiotic therapy, chest drain insertion, intrapleural fibrinolytic therapy and surgery. Antibiotic therapy relies on empirical broad-spectrum antibiotics based on local policies, infection setting and resistance patterns. Chest drain insertion is the mainstay of management, and use of intrapleural fibrinolytics facilitates effective drainage. Surgical interventions such as video-assisted thoracoscopic surgery and decortication are considered in cases not responding to medical therapy. Risk stratification tools such as the RAPID (renal, age, purulence, infection source and dietary factors) score may help guide tailored management. The roles of other modalities such as local anaesthetic medical thoracoscopy and intrapleural antibiotics are debated. Ongoing research aims to improve outcomes by matching interventions with risk profile and to better understand the development of disease.

Associations of physical activity and quality of life in parapneumonic effusion patients

Introduction

Little is known about activity behaviours and quality of life (QoL) of patients with parapneumonic pleural effusions (PPE) after hospital discharge. This study is a secondary analysis of a randomised trial (dexamethasone versus placebo) for hospitalised patients with PPE. We: 1) described the patients' activity behaviour patterns and QoL measured at discharge and at 30 days post-discharge; and 2) examined the association between activity behaviours and QoL scores.

Methods

Activity behaviour (7-day accelerometry; Actigraph GT3X+) and QoL (Medical Outcomes Study Short-Form 36) were assessed. Repeated measures analysis of covariance controlling for baseline values and a series of linear regression models were undertaken.

Results

36 out of 53 eligible participants completed accelerometry assessments. Despite modest increases in light physical activity (+7.5%) and some domains of QoL (>2 points) from discharge to 30 days post-discharge, patients had persistently high levels of sedentary behaviour (>65% of waking wear time) and poor QoL (≤50 out of 100 points) irrespective of treatment group (p=0.135-0.903). Increasing moderate-to-vigorous physical activity was associated with higher scores on most QoL domains (p=0.006-0.037). Linear regression indicates that a clinically important difference of 5 points in physical composite QoL score can be achieved by reallocating 16.1 min·day-1 of sedentary time to moderate-to-vigorous physical activity.

Conclusion

Patients with PPE had low levels of physical activity and QoL at discharge and 30 days post-discharge irrespective of treatment. Moderate-to-vigorous physical activity participation was associated with higher QoL scores. Increasing moderate-to-vigorous physical activity following discharge from the hospital may be associated with improvements in QoL.

Expert Review on Nonsurgical Management of Parapneumonic Effusion: Advances, Controversies, and New Directions

Parapneumonic effusion and empyema are rising in incidence worldwide, particularly in association with comorbidities in an aging population. Also driving this change is the widespread uptake of pneumococcal vaccines, leading to the emergence of nonvaccine-type pneumococci and other bacteria. Early treatment with systemic antibiotics is essential but should be guided by local microbial guidelines and antimicrobial resistance patterns due to significant geographical variation. Thoracic ultrasound has emerged as a leading imaging technique in parapneumonic effusion, enabling physicians to characterize effusions, assess the underlying parenchyma, and safely guide pleural procedures. Drainage decisions remain based on longstanding criteria including the size of the effusion and fluid gram stain and biochemistry results. Small-bore chest drains appear to be as effective as large bore and are adequate for the delivery of intrapleural enzyme therapy (IET), which is now supported by a large body of evidence. The IET dosing regimen used in the UK Multicenter Sepsis Trial -2 has the most evidence available but data surrounding alternative dosing, concurrent and once-daily instillations, and novel fibrinolytic agents are promising. Prognostic scores used in pneumonia (e.g., CURB-65) tend to underestimate mortality in parapneumonic effusion/empyema. Scores specifically based on pleural infection have been developed but require validation in prospective cohorts.

Clinical Risk Factors for Death in Patients With Empyema and Active Malignancy

Background Pleural infection is a common clinical problem resulting in prolonged hospitalization and increased mortality. In patients with active malignancy, management decisions are based on the need for further immunosuppressive therapies, the ability to tolerate surgery, and consideration of the limited life expectancy. Identifying patients at risk for death or poor outcomes is very important as it will guide care. Study design and methods This is a retrospective cohort study of all patients with active malignancy and empyema. The primary outcome was time to death from empyema at three months. The secondary outcome was surgery at 30 days. Standard Cox regression model and cause-specific hazard regression model were used to analyze the data. Results A total of 202 patients with active malignancy and empyema were included. The overall mortality rate at three months was 32.7%. On multivariable analysis, female gender and higher urea were associated with an increased risk of death from empyema at three months. The area under the curve (AUC) of the model was 0.70. The risk factors for surgery at 30 days included the presence of frank pus and postsurgical empyema. The AUC of the model was 0.76. Interpretation Patients with active malignancy and empyema have a high probability of death. In our model, the risk factors for death from empyema included female gender and higher urea.

Phenotyping empyema by pleural fluid culture results and macroscopic appearance: an 8-year retrospective study

Background

The clinical impact of phenotyping empyema is poorly described. This study was designed to evaluate clinical characteristics and outcomes based on the two readily available parameters, pleural fluid culture status and macroscopic fluid appearance.

Methods

A retrospective study was conducted on patients with empyema hospitalised between 2013 and 2020. Empyema was classified into culture-positive empyema (CPE) or culture-negative empyema (CNE) and pus-appearing empyema (PAE) or non-pus-appearing empyema (non-PAE) based on the pleural fluid culture status and macroscopic fluid appearance, respectively.

Results

Altogether, 212 patients had confirmed empyema (CPE: n=188, CNE: n=24; PAE: n=118, non-PAE: n=94). The cohort was predominantly male (n=163, 76.9%) with a mean age of 65.0±13.6 years. Most patients (n=180, 84.9%) had at least one comorbidity. Patients with CPE had higher rates of in-hospital mortality (19.1% versus 0.0%, p=0.017) and 90-day mortality (18.6% versus 0.0%, p=0.017) and more extrapulmonary sources of infection (29.8% versus 8.3%, p=0.026) when compared with patients with CNE. No significant difference in mortality rate was found between PAE and non-PAE during the in-hospital stay and at 30 days and 90 days. Patients with PAE had less extrapulmonary sources of infection (20.3% versus 36.2%, p=0.010) and more anaerobic infection (40.9% versus 24.5%, p=0.017) than those with non-PAE. The median RAPID (renal, age, purulence, infection source, and dietary factors) scores were higher in the CPE and non-PAE groups. After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.

Conclusion

Empyema is a heterogeneous disease with different clinical characteristics. Phenotyping empyema into different subclasses based on pleural fluid microbiological results and macroscopic fluid appearance provides insight into the underlying bacteriology, source of infection and subsequent clinical outcomes.

A narrative review on pain control interventions for non-surgical pleural procedures

Pleural diseases are common and frequently result in disabling symptoms, impaired health-related quality of life and hospitalisation. Both diagnosis and management often require pleural procedures and despite a variety of pain control strategies available for clinicians to employ, many procedures are still complicated by pain and discomfort. This can interfere with procedure success and can limit patient satisfaction. This review examines the evidence for pain control strategies for people undergoing non-surgical pleural procedures. A systematic literature search was undertaken to identify published studies examining different pain control strategies including pharmacological (sedatives, paravertebral blocks, erector spinae blocks, intrapleural anaesthesia, epidural anaesthesia, local anaesthetic, methoxyflurane, non-steroidal anti-inflammatory drugs [NSAIDs], opioids) and non-pharmacological measures (transcutaneous electric nerve stimulation [TENS], cold application and changes to the intervention or technique). Current literature is limited by heterogeneous study design, small participant numbers and use of different endpoints. Strategies that were more effective than placebo or standard care at improving pain included intrapleural local anaesthesia, paravertebral blocks, NSAIDs, small-bore intercostal catheters (ICC), cold application and TENS. Inhaled methoxyflurane, thoracic epidural anaesthesia and erector spinae blocks may also be useful approaches but require further evaluation to determine their roles in routine non-surgical pleural procedures. Future research should utilise reliable and repeatable study designs and reach consensus in endpoints to allow comparability between findings and thus provide the evidence-base to achieve standardisation of pain management approaches.

ERS/ESTS statement on the management of pleural infection in adults

Pleural infection is a common condition encountered by respiratory physicians and thoracic surgeons alike. The European Respiratory Society (ERS) and European Society of Thoracic Surgeons (ESTS) established a multidisciplinary collaboration of clinicians with expertise in managing pleural infection with the aim of producing a comprehensive review of the scientific literature. Six areas of interest were identified: 1) epidemiology of pleural infection, 2) optimal antibiotic strategy, 3) diagnostic parameters for chest tube drainage, 4) status of intrapleural therapies, 5) role of surgery and 6) current place of outcome prediction in management. The literature revealed that recently updated epidemiological data continue to show an overall upwards trend in incidence, but there is an urgent need for a more comprehensive characterisation of the burden of pleural infection in specific populations such as immunocompromised hosts. There is a sparsity of regular analyses and documentation of microbiological patterns at a local level to inform geographical variation, and ongoing research efforts are needed to improve antibiotic stewardship. The evidence remains in favour of a small-bore chest tube optimally placed under image guidance as an appropriate initial intervention for most cases of pleural infection. With a growing body of data suggesting delays to treatment are key contributors to poor outcomes, this suggests that earlier consideration of combination intrapleural enzyme therapy (IET) with concurrent surgical consultation should remain a priority. Since publication of the MIST-2 study, there has been considerable data supporting safety and efficacy of IET, but further studies are needed to optimise dosing using individualised biomarkers of treatment failure. Pending further prospective evaluation, the MIST-2 regimen remains the most evidence based. Several studies have externally validated the RAPID score, but it requires incorporating into prospective intervention studies prior to adopting into clinical practice.

ESBL and carbapenemase-producing Enterobacteriaceae in infectious pleural effusions: current epidemiology at Hôpital du Mali

Background

Antimicrobial resistance (AMR) is a global health concern, with extended-spectrum β-lactamases (ESBLs) and carbapenemases being major contributors. Pleural infection (PI) is a severe condition in West Africa, complicated by AMR. This study aimed to investigate the prevalence and molecular characteristics of ESBL and carbapenemase-producing enterobacteria in pleural effusions in Mali.

Materials and methods

Pleural fluid samples from 526 patients with pleuritis were analyzed. Enterobacterial species were isolated and identified, and the prevalence of resistance genes (blaOXA-48, blaNDM-1, blaKPC, blaTEM, blaSHV) and virulence factors was determined.

Results

Among the patients, 110 were diagnosed with enterobacterial pleuritis. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the main pathogens identified. Resistance to β-lactams and cephalosporins was high, while carbapenems showed good activity. ESBL production was detected in 33.6% of isolates, with blaTEM being the most common gene. Carbapenemase gene (blaNDM-1) was found in three isolates.

Conclusion

The study highlights the high prevalence of multidrug-resistant bacteria and the need for appropriate antibiotic selection based on local resistance patterns. Understanding the molecular characteristics of resistance is crucial for optimizing patient care and developing effective therapeutic strategies. Further research is needed to monitor and control AMR in PIs in Mali.

Does the time to diagnosis and treatment influence outcome in adults with pleural infections

Objective

To investigate the effect of early diagnosis and intervention in adult patients with complicated parapneumonic pleural effusion or pleural empyema and the impact on outcomes.

Methods

A systematic review based on a literature search of the PubMed database was performed.

Results

Eleven eligible studies were included; nine observational studies and two randomised controlled trials totalling a study population of 10,717 patients. The studies were conducted from 1992 to 2018, all in Europe and Northern America except one. Results varied between studies, but a trend towards better outcome in patients with shorter duration of symptoms and quicker initiation of treatment was found. We found that duration of symptoms before treatment may affect length of hospital stay, rate of conversion to open surgery, and frequency of complications.

Conclusion

We found that an earlier intervention in adults suffering from complicated parapneumonic pleural effusion and pleural empyema may potentially improve the outcome of patients in terms of length of stay, conversion to open surgery, and general complications following treatment, but not regarding mortality. Further studies are required to specify the timing of each intervention, and direct comparison in early management of interventions.

Parapneumonic Effusion and Empyema

The rising incidence and high morbidity of pleural infection remain a significant challenge to health care systems worldwide. With distinct microbiology and treatment paradigms from pneumonia, pleural infection is an area in which the evidence base has been rapidly evolving. Progress in recent years has revolved around characterizing the microbiome of pleural infection and the addition of new strategies such as intrapleural enzyme therapy to the established treatment pathway of drainage and antibiotics. The future of improving outcomes lies with personalizing treatment, establishing optimal timing of intrapleural agents and surgery, alongside wider use of risk stratification to guide treatment.

16S rRNA is a valuable tool in finding bacterial aetiology of community-acquired pleural empyema-a population-based observational study in South Sweden

BACKGROUND

The incidence of community-acquired pleural empyema is increasing. Knowledge of the bacterial aetiology is important in order to base recommendations on empirical antimicrobial treatment. The primary aim of the present study was to describe the bacterial aetiology of adult patients with culture proven and/or 16S rRNA-positive community-acquired pleural infection.

METHODS

We performed a retrospective, population-based observational cohort study in Skåne County, south of Sweden. We included all patients with pleural samples obtained between 1st of January 2011 to 31st of December 2017 in Skåne, south of Sweden, with a positive culture and/or 16S rRNA result. Exclusion criteria were patients with culture-negative and/or 16S rRNA-negative pleural samples, age < 18 years, pleural empyema caused by trauma or iatrogenesis, pleural infection caused by tuberculosis or fungi, simultaneous lung- or abscess of the abdomen and bacterial species considered to be contaminants.

RESULTS

A total of 291 patients were included in the study, of which 63% were men and the median age was 69 years. The dominating bacterial aetiology was viridans streptococci (36%), followed by Streptococcus pneumoniae (14%) and anaerobic bacteria (12%). 16S rRNA added information of bacterial aetiology in addition to standard culturing methods in 63% of the patients.

CONCLUSION

We found that the aetiology of adult patients with culture proven and/or 16S rRNA-positive community-acquired pleural empyema is dominated by viridans streptococci, S. pneumoniae and anaerobic bacteria. Our study shows that 16S rRNA is a valuable tool in finding the bacterial aetiology of community-acquired pleural empyema.

Recent Insights into the Management of Pleural Infection

Pleural infection in adults has considerable morbidity and continues to be a life-threatening condition. The term “pleural infection” encompasses complicated parapneumonic effusions and primary pleural infections, and includes but is not limited to empyema, which refers to collection of pus in the pleural cavity. The incidence of pleural infection in adults has been continuously increasing over the past two decades, particularly in older adults, and most of such patients have comorbidities. Management of pleural infection requires prolonged duration of hospitalization (average 14 days). There are recognized differences in microbial etiology of pleural infection depending on whether the infection was acquired in the community or in a health-care setting. Anaerobic bacteria are acknowledged as a major cause of pleural infection, and thus anaerobic coverage in antibiotic regimens for pleural infection is mandatory. The key components of managing pleural infection are appropriate antimicrobial therapy and chest-tube drainage. In patients who fail medical therapy by manifesting persistent sepsis despite standard measures, surgical intervention to clear the infected space or intrapleural fibrinolytic therapy (in poor surgical candidates) are recommended. Recent studies have explored the role of early intrapleural fibrinolytics or first-line surgery, but due to considerable costs of such interventions and the lack of convincing evidence of improved outcomes with early use, early intervention cannot be recommended, and further evidence is awaited from ongoing studies. Other areas of research include the role of routine molecular testing of infected pleural fluid in improving the rate of identification of causative organisms. Other research topics include the benefit of such interventions as medical thoracoscopy, high-volume pleural irrigation with saline/antiseptic solution, and repeated thoracentesis (as opposed to chest-tube drainage) in reducing morbidity and improving outcomes of pleural infection. This review summarizes current knowledge and practice in managing pleural infection and future research directions.

Intrapleural Fibrinolytics and Deoxyribonuclease for Treatment of Indwelling Pleural Catheter-Related Pleural Infection: A Multi-Center Observational Study

BACKGROUND

Indwelling pleural catheters (IPC) are increasingly used for management of recurrent (especially malignant) effusions. Pleural infection associated with IPC use remains a concern. Intrapleural therapy with tissue plasminogen activator (tPA) and deoxyribonuclease (DNase) significantly reduces surgical referrals in non-IPC pleural infection, but data on its use in IPC-related pleural infection are scarce.

OBJECTIVE

To assess the safety and efficacy of intrapleural tPA and DNase in IPC-related pleural infection.

METHODS

Patients with IPC-related pleural infection who received intrapleural tPA/DNase in five Australian and UK centers were identified from prospective databases. Outcomes on feasibility of intrapleural tPA/DNase delivery, its efficacy and safety were recorded.

RESULTS

Thirty-nine IPC-related pleural infections (predominantly Staphylococcus aureus and gram-negative organisms) were treated in 38 patients; 87% had malignant effusions. In total, 195 doses (median 6 [IQR = 3-6]/patient) of tPA (2.5 mg-10 mg) and DNase (5 mg) were instilled. Most (94%) doses were delivered via IPCs using local protocols for non-IPC pleural infections. The mean volume of pleural fluid drained during the first 72 h of treatment was 3,073 (SD = 1,685) mL. Most (82%) patients were successfully treated and survived to hospital discharge without surgery; 7 required additional chest tubes or therapeutic aspiration. Three patients required thoracoscopic surgery. Pleurodesis developed post-infection in 23/32 of successfully treated patients. No major morbidity/mortality was associated with tPA/DNase. Four patients received blood transfusions; none had systemic or significant pleural bleeding.

CONCLUSION

Treatment of IPC-related pleural infection with intrapleural tPA/DNase instillations via the IPC appears feasible and safe, usually without additional drainage procedures or surgery. Pleurodesis post-infection is common.

Identification of Microbiome Etiology Associated With Drug Resistance in Pleural Empyema

Identification of the offending organism and appropriate antimicrobial therapy are crucial for treating empyema. Diagnosis of empyema is largely obscured by the conventional bacterial cultivation and PCR process that has relatively low sensitivity, leading to limited understanding of the etiopathogenesis, microbiology, and role of antibiotics in the pleural cavity. To expand our understanding of its pathophysiology, we have carried out a metagenomic snapshot of the pleural effusion from 45 empyema patients by Illumina sequencing platform to assess its taxonomic, and antibiotic resistome structure. Our results showed that the variation of microbiota in the pleural effusion is generally stratified, not continuous. There are two distinct microbiome clusters observed in the forty-five samples: HA-SA type and LA-SA type. The categorization is mostly driven by species composition: HA-SA type is marked by Staphylococcus aureus as the core species, with other enriched 6 bacteria and 3 fungi, forming a low diversity and highly stable microbial community; whereas the LA-SA type has a more diverse microbial community with a distinct set of bacterial species that are assumed to be the oral origin. The microbial community does not shape the dominant antibiotic resistance classes which were common in the two types, while the increase of microbial diversity was correlated with the increase in antibiotic resistance genes. The existence of well-balanced microbial symbiotic states might respond differently to pathogen colonization and drug intake. This study provides a deeper understanding of the pathobiology of pleural empyema and suggests that potential resistance genes may hinder the antimicrobial therapy of empyema.

Asymptomatic man with an incidental finding of a massive empyema

We describe the case of a 67-year-old asymptomatic man who was referred to our hospital for abnormal laboratory results. He was incidentally found to have a massive empyema without underlying bronchopulmonary pneumonia. Following thoracentesis, he was diagnosed with chronic Streptococcus anginosus empyema. Therapeutic thoracentesis and treatment with tissue plasminogen activator and deoxyribonuclease failed to resolve the empyema, and there was residual loculated pleural fluid that was surrounded by a thick rind. The patient was referred to thoracic surgery for decortication of the pleural space via video-assisted thoracoscopic surgery. At 2-month follow-up, the patient had complete re-expansion of the lung tissue.

Two vs. three weeks of treatment with amoxicillin-clavulanate for stabilized community-acquired complicated parapneumonic effusions. A preliminary non-inferiority, double-blind, randomized, controlled trial

Background

The optimal duration of antibiotic treatment for complicated parapneumonic effusions (CPPEs) has not been properly defined. Our aim was to compare the efficacy of amoxicillin-clavulanate for 2 vs. 3 weeks in patients with CPPE (i.e. those which required chest tube drainage).

Methods

In this non-inferiority, randomized, double-blind, controlled trial, patients with community-acquired CPPE were recruited from two centers in Spain and, after having obtained clinical stability following 2 weeks of amoxicillin-clavulanate, they were randomly assigned to placebo or antibiotic for an additional week. The primary objective was clinical success, tested for a non-inferiority margin of<10%. Secondary outcomes were the proportion of residual pleural thickening of>10 mm at 3 months, and adverse events. The study was registered with EudraCT, number 2014-003137-25. We originally planned to randomly assign 284 patients.

Results

After recruiting 55 patients, the study was terminated early owing to slow enrolment. A total of 25 patients were assigned to 2 weeks and 30 patients to 3 weeks of amoxicillin-clavulanate. Clinical success occurred in the 25 (100%) patients treated for 2 weeks and 29 (97%) treated for 3 weeks (difference 3%, 95% CI −3 to 9.7%). Respective between-group differences in the rate of residual pleural thickening (−12%, 95%CI −39 to 14%) and adverse events (−7%, 95%CI −16 to 2%) did not reach statistical significance.

Conclusions

In this small series of selected adult patients with community-acquired CPPE, amoxicillin-clavulanate treatment could be safely discontinued by day 14 if clinical stability was obtained.

A systematic review of comorbidities and outcomes of adult patients with pleural infection

Background

Pleural infection remains an important cause of mortality. This study aimed to investigate worldwide patterns of pre-existing comorbidities and clinical outcomes of patients with pleural infection.

Methods

Studies reporting on adults with pleural infection between 2000 and 2017 were identified from a search of Embase and MEDLINE. Articles reporting exclusively on tuberculous, fungal or post-pneumonectomy infection were excluded. Two reviewers assessed 20 980 records for eligibility.

Results

211 studies met the inclusion criteria. 134 articles (227 898 patients, mean age 52.8 years) reported comorbidity and/or outcome data. The majority of studies were retrospective observational cohorts (n=104, 78%) and the most common region of reporting was East Asia (n=33, 24%) followed by North America (n=27, 20%). 85 articles (50 756 patients) reported comorbidity. The median (interquartile range (IQR)) percentage prevalence of any comorbidity was 72% (58–83%), with respiratory illness (20%, 16–32%) and cardiac illness (19%, 15–27%) most commonly reported. 125 papers (192 298 patients) reported outcome data. The median (IQR) length of stay was 19 days (13–27 days) and median in-hospital or 30-day mortality was 4% (IQR 1–11%). In regions with high-income economies (n=100, 74%) patients were older (mean 56.5 versus 42.5 years, p<0.0001), but there were no significant differences in prevalence of pre-existing comorbidity nor in length of hospital stay or mortality.

Conclusion

Patients with pleural infection have high levels of comorbidity and long hospital stays. Most reported data are from high-income economy settings. Data from lower-income regions is needed to better understand regional trends and enable optimal resource provision going forward.

In pleural infection, patients from higher-income countries tend to be older with more comorbidities and are more likely to be referred for fibrinolytic treatment in comparison to patients from lower-income countrieshttp://bit.ly/2K2M5HL