Isolation and identification of hoylesella marshii causing pleural infection: a case report.

BACKGROUND: Hoylesella marshii can be isolated from human oral cavities affected by dental pulp and periodontal infections, as well as from the dental plaque of healthy individuals, making it a common bacterium within the oral microbiota. However, its role in causing pleural infections in humans is rare. CASE PRESENTATION: A case of purulent pleural effusion occurred shortly after discharge in an elderly patient who had undergone surgery for gastric cancer. The infection was identified as being caused by an obligate anaerobe through laboratory culture, and was further identified as Hoylesella marshii causing pleural infection through 16 S rRNA gene sequence analysis. Susceptibility testing guided precise treatment with cefoperazone-sulbactam and metronidazole. The patient's clinical symptoms improved rapidly, laboratory test indicators gradually returned to normal, and the patient ultimately recovered. CONCLUSION: Hoylesella marshii can cause pleural infections in humans. Clinical microbiology laboratories should pay special attention to the cultivation of obligate anaerobes when routine aerobic cultures do not show bacterial growth but bacteria are visible on smear staining, and when conventional identification methods fail to identify the bacterium, analysis based on the highly conserved 16 S rRNA gene sequence can accurately and specifically identify the bacterium, guiding clinicians in formulating precise anti-infection strategies.

Prospective evaluation of thin-layer agar colour test in routine diagnosis of multidrug-resistant TB.

This study evaluated the diagnostic performance of the thin-layer agar MDR/XDR-TB Colour Test (CT), a Mycobacterium tuberculosis complex (MTBC) detection and direct drug susceptibility testing (DST) method with routine sputum, bronchoalveolar lavage and pleural fluid specimen.In a prospective study, the time and rate of MTBC detection were compared between CT, Löwenstein-Jensen, and MGIT media. Times until DST result, sensitivities, and specificities were evaluated between CT and MGIT 960 indirect DST.The cultivation of 177 pulmonary specimens resulted in 83 MTBC-positive cultures. The sensitivity of CT for MTBC detection was 81.3% with a median time of 20 days compared to 13 days and 93.5% for MGIT. The sensitivity of CT for DST results was 100% for isoniazid and levofloxacin and 94.7% for rifampicin. The specificities for isoniazid and rifampicin DST were 97.3% and 98.0% for levofloxacin. The median time until a DST result was significantly shorter with CT than the BACTEC MGIT 960 system, 20 and 27 days, respectively, independent of the specimen type used.The CT is a highly accurate and fast initial diagnostic test for high-incidence settings and could also be used as a first culture and direct DST in peripheral settings..

Severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii and Penicillium oxalicum in a diabetic patient.

BACKGROUND PAECILOMYCES: and Penicillium are considered as rare opportunistic pathogens in immunocompromised hosts, and pneumonia caused by Paecilomyces and Penicillium is rare. In this study, we present first case of severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii (P. variotii) and Penicillium oxalicum (P. oxalicum) in a 66-year-old female with poorly controlled type 2 diabetes. CASE PRESENTATION: A 56-year-old woman patient presented to hospital for nausea, poor appetite, and vomiting for one day. On the second day of admission, blood culture and renal puncture fluid culture grew multidrug-resistant Escherichia coli (imipenem/cilastatin sensitive), and she received combination therapy with imipenem/cilastatin (1 g, every 8 h) and vancomycin (0.5 g, every 12 h). On the fourth day, she developed symptoms of respiratory failure. Pulmonary computed tomography (CT) showed an increase in pneumonia compared to before, with minor pleural effusion on both sides. Two fungi were isolated repeatedly from BALF culture, which were confirmed as P. variotii and P. oxalicum by Internal transcribed spacer (ITS) sequencing. Her pleural effusion was completely absorbed, pneumonia symptoms have significantly improved and discharged with receiving liposomal amphotericin B treatment for four weeks. CONCLUSIONS: It is worth noting that clinicians and laboratory personnel should not simply consider Paecilomyces and Penicillium species as contaminants, especially in immunocompromised patients. Early fungal identification and antifungal drug sensitivity are crucial for clinical drug selection and patient prognosis.

Aetiology of pleural effusions in children living in a high TB endemic setting.

Confirming the aetiology of pleural effusion in children may be difficult in TB-endemic settings. We investigated the role of polymerase chain reaction (PCR) and routine biochemical tests in discriminating pleural effusion caused by bacteria from other aetiologies.This is a cross-sectional post-hoc analysis among children with pleural effusion in a tertiary hospital in South Africa, incorporating new data from PCR testing of stored pleural fluid. Aetiological classification was defined by microbiological confirmation.Ninety-one children were enrolled; the median age 31 months (IQR 12-102). The aetiology of pleural effusion was 40% (36/91) bacteria, 11% (10/91) TB, 3% (3/91) viruses, 11% (10/91) polymicrobial and 35% (32/91) had no pathogen identified. The most common pathogen was Staphylococcus aureus (27/91, 30%) with similar yields on culture and PCR, followed by Streptococcus pneumoniae (12/91, 13%), detected more commonly by PCR. PCR reduced the number of children with unconfirmed aetiologies from 48 to 32. Characteristics of children with no pathogen most resembled those with TB. Pleural fluid lactate dehydrogenase ≥1,716 U/L best discriminated bacterial pleural effusion from other aetiologies (sensitivity of 86%; specificity 95%).PCR improved detection of pathogens and reduced number of children with unconfirmed aetiologies in presumed exudative pleural effusion..

Pleurisy due to brucellosis.

Any system or organ involvement can be seen in brucellosis, which is still a significant public health problem in developing countries. The rate of respiratory system involvement is lower than that of other systems and which is also difficult to document. Brucellosis-associated pleurisy is a rare complication even in endemic regions. In this case report, a 78-year-old male patient who was assessed for pleural effusion etiology is presented. Brucella spp. were isolated on the 14th day of the pleural fluid incubation in the blood culture set and the patienthas been treated successfully for brucellosis. Based on our experience we think that it is important to use blood culture media for sterile body fluids, particularly for microorganisms that are difficult to isolate such as Brucella spp.

The regulation and potential role of interleukin-32 in tuberculous pleural effusion.

The possible protective effect of interleukin-32 (IL-32) in Mycobacterium tuberculosis (Mtb) infection has been indicated. However, few studies have been focused on IL-32 in tuberculosis patients. Additionally, the regulation of IL-32 production has rarely been reported. In the present study, the production, regulation, and role of IL-32 in tuberculous pleurisy (TBP) were investigated. We found that the content of IL-32 in tuberculous pleural effusion (TPE) was higher than the level in the malignant pleural effusion and transudative pleural effusion. The level of IL-32 mRNA in pleural fluid mononuclear cells (PFMCs) was higher than that in peripheral blood mononuclear cells (PBMCs) of patients with TBP, and this difference was mainly reflected in the splice variants of IL-32α, IL-32ß, and IL-32γ. Compared with the PBMCs, PFMCs featured higher IL-32ß/IL-32γ and IL-32α/IL-32γ ratios. In addition, lipopolysaccharide (LPS), Bacillus Calmette-Guérin (BCG), and H37Ra stimulation could induce IL-32 production in the PFMCs. IL-32 production was positively correlated with the TNF-α, IFN-γ, and IL-1Ra levels in TPE, whereas IFN-γ, but not TNF-α or IL-1Ra, could induce the production of IL-32 in PFMCs. Furthermore, IL-32γ could induce the TNF-α production in PFMCs. Monocytes and macrophages were the main sources of IL-32 in PFMCs. Nevertheless, direct cell-cell contact between lymphocytes and monocytes/macrophages plays an important role in enhancing IL-32 production by monocyte/macrophage cells. Finally, compared with the non-tuberculous pleural effusion, the purified CD4+ and CD8+ T cells in TPE expressed higher levels of intracellular IL-32. Our results suggested that, as a potential biomarker, IL-32 may play an essential role in the protection against Mtb infection in patients with TBP. However, further studies need to be carried out to clarify the functions and mechanisms of the IFN-γ/IL-32/TNF-α axis in patients with TBP.

Empiric Antibiotic Therapy in 1402 Children With Parapneumonic Effusion/Pleural Empyema in Germany: A Long-term Surveillance Study.

OBJECTIVE: This study investigated empiric antibiotic treatment (EAT), guideline adherence, antibiotic streamlining and clinical outcomes in 1402 hospitalized children with pediatric parapneumonic effusion/pleural empyema (PPE/PE). METHODS: A nationwide surveillance study collected data on EAT, clinical course/outcome, pathogens, susceptibility testing and antibiotic streamlining of children with PPE/PE in Germany between 2010 and 2018. Subgroups were compared using χ2 test/Fisher exact test, Mann-Whitney U test and linear regression analysis adjusting for patient age where appropriate. RESULTS: Complete data on EAT were available for 1402 children. In children with monotherapy (n = 567) and in children with combination therapy of 2 antibiotics (n = 589), the most commonly used antibiotics were aminopenicillin/beta-lactamase inhibitor [138/567 (24.3%) and 102/589 (17.3%)] and cefuroxime [291/567 (51.3%) and 294/589 (49.9%)]. The most common combinations with these beta-lactams were macrolides, aminoglycosides and clindamycin. We observed no difference in clinical severity/outcome between EAT with aminopenicillin/beta-lactamase inhibitor and cefuroxime, neither when used in monotherapy nor when used in combination therapy of 2 antibiotics. Species diagnosis of Streptococcus pneumoniae (n = 192), Streptococcus pyogenes (n = 111) or Staphylococcus aureus (n = 38) in polymerase chain reaction or culture from pleural fluid or blood resulted in a switch to an appropriate narrow-spectrum beta-lactam therapy in 9.4%, 18.9 % and 5.2% of children. In a subset of children with reported bacterial susceptibility testing, penicillin resistance was reported in 3/63 (4.8%) of S. pneumoniae and methicillin resistance in S. aureus was reported in 10/32 (31.3%) of children. CONCLUSION: This study points to antibiotic overtreatment in children with PPE/PE, particularly the frequent use of combinations of antibiotics. Children receiving combinations of antibiotics did not show differences in clinical outcomes. The low rate of children with streamlined antibiotic therapy even upon pathogen detection indicates a necessity for antibiotic stewardship measures in PPE/PE and the need of investigating other potential therapeutic strategies as anti-inflammatory therapy.

Acute Q fever revealed by an anti-phospholipid syndrome: A case report.

INTRODUCTION: Q fever is a zoonosis caused by Coxiella burnetii. Acute infection is mainly asymptomatic. In other cases it mainly causes a flu-like illness, a pneumonia, or an hepatitis. We present an atypical case of an acute Q fever revealed by a massive pleural effusion. CASE REPORT: We report the case of a 43-year-old man referred to our hospital for an acute respiratory distress. Further analyses showed an exudative eosinophilic pleural effusion, associated with a pulmonary embolism and a deep femoral vein thrombosis. Aetiologic explorations revealed an acute Q fever (IgM and IgG against C. burnetii phase II antigens) associated with anti-phospholipids. The outcome was favorable with vitamin K antagonists, doxycycline, and hydroxychloroquine, till the negativation of the anti-phospholipid antibodies. DISCUSSION AND CONCLUSION: During acute C. burnetii infections, anti-phospholipid antibodies are highly prevalent but thrombotic complications are rare. The 2023 ACR/EULAR APS criteria restricts the diagnosis of APS, as in our case of acute severe infection. In front of an atypical pneumonia and/or thrombotic events, screening of C. burnetii and anti-phospholipid antibodies could be useful. Given its low level of evidence, prolongated treatment by doxycycline, hydroxychloroquine ± anticoagulant for C. burnetii's associated anti-phospholipid syndrome is discussed, but succeeded in our case.

Enhanced differential evolution algorithm for feature selection in tuberculous pleural effusion clinical characteristics analysis.

Tuberculous pleural effusion poses a significant threat to human health due to its potential for severe disease and mortality. Without timely treatment, it may lead to fatal consequences. Therefore, early identification and prompt treatment are crucial for preventing problems such as chronic lung disease, respiratory failure, and death. This study proposes an enhanced differential evolution algorithm based on colony predation and dispersed foraging strategies. A series of experiments conducted on the IEEE CEC 2017 competition dataset validated the global optimization capability of the method. Additionally, a binary version of the algorithm is introduced to assess the algorithm's ability to address feature selection problems. Comprehensive comparisons of the effectiveness of the proposed algorithm with 8 similar algorithms were conducted using public datasets with feature sizes ranging from 10 to 10,000. Experimental results demonstrate that the proposed method is an effective feature selection approach. Furthermore, a predictive model for tuberculous pleural effusion is established by integrating the proposed algorithm with support vector machines. The performance of the proposed model is validated using clinical records collected from 140 tuberculous pleural effusion patients, totaling 10,780 instances. Experimental results indicate that the proposed model can identify key correlated indicators such as pleural effusion adenosine deaminase, temperature, white blood cell count, and pleural effusion color, aiding in the clinical feature analysis of tuberculous pleural effusion and providing early warning for its treatment and prediction.

Invasive disease caused simultaneously by two different serotypes of Streptococcus pneumoniae: a microbiological appreciation.

We report a clinical case of a child with an invasive pneumococcal disease caused by two different pneumococcal serotypes that belonged to different sequence types. She was a 15-month-old girl with pneumonia and pleural effusion in which S. pneumoniae colonies with different morphologies grew, one from the blood culture (characteristic greyish appearance) and the other from the pleural fluid (mucoid appearance). The isolate from blood was serotype 22 F (ST698/CC698/GPSC61), while the isolate from the pleural fluid was serotype 3 (ST180/CC180/GPSC12). The patient fully recovered after treatment with intravenous ampicillin followed by oral amoxicillin.

Rapid detection of S. pyogenes and S. pneumoniae in pleural fluid for diagnosis of parapneumonic empyema.

The aim of this study was to assess the reliability of rapid antigen detection tests (RADT) for Streptococcus pyogenes (GAS) and Streptococcus pneumoniae on pleural fluid samples for diagnosis of parapneumonic effusion/empyema (PPE) and their potential for improving pathogen identification rates. Sixty-three pleural samples were included from 54 patients on which GAS and S. pneumoniae RADT (BinaxNOW), culture, 16S rRNA PCR, and S. pneumoniae-specific PCR were performed. GAS RADT showed a sensitivity of 95.2% and a specificity of 100%. Pneumococcal RADT showed a sensitivity of 100% and specificity of 88.6%. Both RADT increased the pathogen identification rate in PPE compared to culture.

Diagnostic value of nucleic acid amplification tests for tuberculous pleural effusion.

Diagnosing tuberculous pleural effusion (TPE) is challenging for pulmonologists and laboratory scientists. The gold standards for TPE diagnosis are pleural fluid Ziehl-Neelsen staining, Mycobacterium tuberculosis (Mtb) culture and pleural biopsy. These tools have limitations, including low sensitivity, long turnaround time and invasiveness. The nucleic acid amplification test (NAAT) is a rapid and minimally invasive tool for diagnosing TPE. This review summarizes the diagnostic accuracy of available NAATs for TPE, with a focus on the evidence from systematic reviews and meta-analyses. The NAATs summarized in this review include in-house NAATs, GeneXpert-MTB/RIF, GeneXpert-MTB/RIF Ultra, simultaneous amplification and testing-tuberculosis, FluoroType MTB and loop-mediated isothermal amplification.

Pulmonary tuberculosis among patients of tubercular pleural effusion: A single-center experience.

Objective: To find out the prevalence of active pulmonary tuberculosis (TB) amongst patients of tubercular pleural effusion and to find out any direct association between tubercular pleural effusion and active pulmonary TB. Methods: This was an observational study conducted in eastern India amongst patients of tubercular pleural effusion. Laboratory and radiological investigations were done for all of the patients. Patients with microbiological/radiological evidence of active pulmonary TB were classified as having primary disease. Rest of the patients were classified as having reactivated disease. Results: A total of 50 patients were recruited in this study. Only 4 patients (8%) had radiological/microbiological evidence of active parenchymal TB. There was no difference in terms of demographic and laboratory features between patients with primary and reactivated disease. Conclusion: Active pulmonary TB was found amongst a minority (4%) of cases of tubercular pleural effusion with reactivation of the past or, latent TB infection being responsible for the majority of the cases.

Diagnosis of tuberculous pleural effusion in a tertiary care hospital of central India: The role of xpert Mycobacterium tuberculosis/rifampicin.

Background: In India, 15%-20% of tuberculosis (TB) cases are categorized as extra-pulmonary TB, and tuberculous pleural effusion (TPE) is the second-most common type after tuberculous lymphadenitis. However, the paucibacillary nature of TPE makes its diagnosis challenging. As a result, relying on empirical anti-TB treatment (ATT) based on clinical diagnosis becomes necessary for achieving the best possible diagnostic outcome. The study aims to determine the diagnostic utility of Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) for the detection of TB in TPE in high incidence setting of Central India. Methods: The study enrolled 321 patients who had exudative pleural effusion detected through radiological testing and were suspected of having TB. The medical procedure of thoracentesis was conducted to collect the pleural fluid, which was then subjected to both the Ziehl-Neelsen staining and Xpert MTB/RIF test. The patients who showed improvement after receiving anti-tuberculosis treatment (ATT) were considered the composite reference standard. Results: The sensitivity of smear microscopy was found to be 10.19%, while that of the Xpert MTB/RIF method was 25.93% when compared to the composite reference standard. The accuracy of clinical diagnosis was measured using receiver operating characteristics based on clinical symptoms, and it was found to be 0.858 (area under the curve). Conclusions: The study shows that Xpert MTB/RIF has significant value in diagnosing TPE, despite its low sensitivity of 25.93%. Clinical diagnosis based on symptoms was relatively accurate, but relying on symptoms alone is not enough. Using multiple diagnostic tools, including Xpert MTB/RIF, is crucial for accurate diagnosis. Xpert MTB/RIF has excellent specificity and can detect RIF resistance. Its quick results make it useful in situations where a rapid diagnosis is necessary. While it should not be the only diagnostic tool, it has a valuable role in diagnosing TPE.

Paraffin-embedded Sample Test Promotes the Diagnosis of Tuberculous Pleurisy.

Context: Tuberculous pleurisy (TP) is the most common manifestation of extrapulmonary tuberculosis and the most frequent cause of pleural effusion (PE). Clinicians make a definitive diagnosis of TP based on the isolation of the mycobacterium tuberculosis (MTB) from PE or a pleural biopsy. Since the currently available tests for TP all have limitations in making a definitive diagnosis, clinicians urgently need new diagnostic tests. Objective: The study intended to compare the value in clinically diagnosing TP of the paraffin-embedded sample test (PEST), using pleural-effusion samples; an adenosine deaminase assay (ADA) using pleural fluid; and the T cell enzyme-linked immunospot test (T-SPOT), using peripheral-blood. Design: The research team performed a retrospective observational study. Setting: The study took place at the Sir Run Run Hospital, Nanjing Medical University in Nanjing, Jiangsu, China. Participants: Participants were 37 patients with suspected TP who had been admitted to the hospital between September 2018 and December 2022. Outcome Measures: The research team assessed the diagnostic performance of PEST, ADA, and T-SPOT in the TP group, calculating the positive rate, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the tests. Results: Among the 37 participants, the testing confirmed that 24 had TP (64.86%), with 13 not having TP (35.14%). The PEST test produced a sensitivity of 83.3% for TP, with 20 out of 24 participants in the TP group testing positive (95% CI: 61.8 to 94.5), which was superior to the ADA, with only 9 out of the 24 participants (37.5%) in the TP group testing positive (95% CI: 19.6 to 59.2), with P < .001. Conclusions: The PEST test possesses a high diagnostic value, and clinicians can use it as a time-saving, noninvasive, and highly sensitive method for TP diagnosis. It can be adjunct method to the currently used tests for diagnosing TP. A combination of several detection methods could promote effective treatment.

Pericardial computed tomography imaging findings in the setting of coccidioidomycosis.

BACKGROUND: Pericardial disease can be a manifestation of infection and imaging can have a role in its diagnosis. coccidioidomycosis endemic fungal infection has been more frequently reported over the past few decades. Other than case reports or series, there has been no systemic study evaluating pericardial imaging findings in patients with coccidioidomycosis to the best of our knowledge. The purpose of this study was to evaluate intrathoracic computed tomographic (CT) imaging abnormalities in patients with coccidioidal infection with specific emphasis on the pericardium. METHODS: Retrospective review of radiology reports and clinical chart review was performed to identify patients with coccidioidomycosis between January 2000 and September 2021 at our medical center. Diagnosis of infection was confirmed predominately with serology. Patients were excluded if a CT was not performed within 3 months of confirmed diagnosis date and if there was concomitant additional granulomatous or fungal infection. Chest CT was reviewed for pericardial and additional intrathoracic findings. RESULTS: The final retrospective cohort consisted of 37 patients. Imaging findings included lung nodules (N = 33/37), consolidation (N = 25/37), mediastinal or hilar lymphadenopathy (N = 20/37) and pleural effusions (N = 13/37). Eleven of 37 patients (30%) had either trace pericardial fluid (N = 3/37) or small pericardial effusions (N = 8/37). One patient had pericardial enhancement/thickening and history of pericardial tamponade. No other patient had clinical pericarditis or pericardial tamponade. Pericardial calcifications were not seen in any patient. Pericardial effusion was statistically associated with presence of pleural effusion as 9/13 patients with pleural effusion had pericardial effusion versus 2/26 patients without pleural effusion had pericardial effusion (p < 0.001). Otherwise patients with and without pericardial imaging findings were similar in terms of demographics, comorbidities and other imaging findings. CONCLUSION: Pulmonary parenchymal pathology is a common manifestation of coccidioidal infection. Most patients with coccidioidomycosis do not have pericardial imaging abnormalities on CT.

Xpert MTB/RIF Ultra versus Xpert MTB/RIF for diagnosis of tuberculous pleural effusion: A systematic review and comparative meta-analysis.

OBJECTIVE: We compared diagnostic accuracy of pleural fluid Xpert MTB/RIF (Xpert) and Xpert MTB/RIF Ultra (Ultra) assays for diagnosing tuberculous pleural effusion (TPE), through systematic review and comparative meta-analysis. METHODS: We searched PubMed and Embase databases for publications reporting diagnostic accuracy of Xpert or Ultra for TPE. We used bivariate random-effects modeling to summarize diagnostic accuracy information from individual studies using either mycobacterial culture or composite criteria as reference standard. We performed meta-regression through hierarchical summary receiver operating characteristic (HSROC) modeling to evaluate comparative performance of the two tests from studies reporting diagnostic accuracy of both in the same study population. RESULTS: We retrieved 1097 publications, and included 74 for review. Summary estimates for sensitivity and specificity for Xpert were 0.52 (95% CI 0.43-0.60, I2 82.1%) and 0.99 (95% CI 0.97-0.99, I2 85.1%), respectively, using culture-based reference standard; and 0.21 (95% CI 0.17-0.26, I2 81.5%) and 1.00 (95% CI 0.99-1.00, I2 37.6%), respectively, using composite reference standard. Summary estimates for sensitivity and specificity for Ultra were 0.68 (95% CI 0.55-0.79, I2 80.0%) and 0.97 (95% CI 0.97-0.99, I2 92.1%), respectively, using culture-based reference standard; and 0.47 (95% CI 0.40-0.55, I2 64.1%) and 0.98 (95% CI 0.95-0.99, I2 54.8%), respectively, using composite reference standard. HSROC meta-regression yielded relative diagnostic odds ratio of 1.28 (95% CI 0.65-2.50) and 1.80 (95% CI 0.41-7.84) respectively in favor of Ultra, using culture and composite criteria as reference standard. CONCLUSION: Ultra provides superior diagnostic accuracy over Xpert for diagnosing TPE, mainly because of its higher sensitivity.

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.