Single-centre observational study of the safety and efficacy of thoracoscopy under local anaesthesia for the management of thoracic infections

OBJECTIVES

Thoracoscopy under local anaesthesia is widely performed to diagnose malignancies and infectious diseases. However, few reports have described the use of this procedure for diagnosing and treating intrathoracic infections. This study aimed to evaluate the safety and efficacy of thoracoscopy under local anaesthesia for the management of intrathoracic infections.

RESULTS

Data from patients who underwent thoracoscopy procedures performed by chest physicians under local anaesthesia at our hospital between January 2018 and December 2023 were retrospectively reviewed. We analysed their demographic factors, reasons for the examinations, diseases targeted, examination lengths, anaesthetic methods used, diagnostic and treatment success rates, as well as any adverse events. Thirty patients were included. Of these, 12 (40%) had thoracoscopies to diagnose infections, and 18 (60%) had them to treat pyothorax. In terms of diagnosing pleurisy, the causative microorganism of origin was identified via thoracoscopy in only three of 12 (25.0%) patients. For diagnosing pyothorax, the causative microorganism was identified in 7 of 18 (38.9%) patients. Methicillin-resistant Staphylococcus aureus was the most common causative microorganism identified. The treatment success rates were very high, ranging between 94.4 and 100%, whereas the identification rate of the causative microorganisms behind infections was low, ranging between 25.0 and 38.9%. The most frequent adverse events included perioperative hypoxaemia and pain. There were two (6.7%) serious adverse events of grade ≥ 3, but none resulted in death.

CONCLUSIONS

The efficacy of managing intrathoracic infections through thoracoscopy under local anaesthesia is commendable. Nonetheless, the diagnostic accuracy of the procedure, regarding the precise identification of the causative microorganisms responsible for intrathoracic infections, persists at a notably low level, presenting a substantial clinical hurdle.

A comparative analysis between next-generation sequencing and conventional culture method to detect empyema-associated microorganisms: A systematic review

Empyema poses a significant global health concern, yet identifying responsible bacteria remains elusive. Recent studies question the efficacy of conventional pleural fluid culture in accurately identifying empyema-causing bacteria. The aim of this study was to compare diagnostic capabilities of next-generation sequencing (NGS) with conventional pleural fluid culture in identifying empyema-causing bacteria. Five databases (Google Scholar, Science Direct, Cochrane, Research Gate, and PubMed) were used to search studies comparing conventional pleural fluid culture with NGS for identifying empyema-causing bacteria using keywords. Positive results identified through conventional pleural fluid culture and NGS were extracted. In addition, bacterial profiles identified by NGS were also documented. Joanna-Briggs Institute (JBI) critical appraisal tool was employed to assess quality of included studies. Descriptive analysis was employed to present outcome of interests. From five databases, three studies, with 354 patients, were included. Findings from three studies showed that NGS outperformed conventional pleural fluid culture in detecting empyema-causing bacteria even in culture-negative samples. Moreover, dominant bacterial profiles identified through NGS included Streptococcus pneumoniae, Staphylococcus aureus, and anaerobic bacteria. In conclusion, NGS outperforms conventional pleural fluid culture in detection empyema-causing bacteria, yet further studies with larger samples and broader bacterial profiles are needed to increase confidence and urgency in its adoption over conventional pleural fluid culture.

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.

Fusobacterium/Peptostreptococcus - A Case Report of Community- Acquired Empyema Resulting in Surgical Decortication with Prolonged Antibiotic Therapy: A Case Series and Review of the Literature

Background: Infections caused by anaerobic bacteria occur frequently and can be serious and life-threatening. Anaerobes are a rare cause of community-acquired pneumonia with Streptococcus pneumonia and respiratory viruses being the most frequently detected pathogens. We, herein, report a case of Fusobacterium/Peptostreptococcus parapneumonic effusion with empyema in a patient without risk factors for aspiration pneumonia. This case presents an opportunity to discuss an unusual case of community-acquired empyema secondary to anaerobic infection in a patient without the common risk factors for aspiration.

Case Presentation: A 59-year-old male patient without significant past medical history apart from a twenty-five-year history of smoking presented due to left flank pain and shortness of breath. Findings of a complicated parapneumonic effusion were found on imaging, resulting in surgical decortication and prolonged antibiotic therapy.

Discussion: Parapneumonic effusions and empyema are relatively common complications of pneumonia. It is important to note that the incidence of anaerobic empyema has been on the rise due to more modern culturing techniques.

Conclusion: This case highlights an unusual presentation of community-acquired empyema secondary to anaerobes without any risk factors for aspiration pneumonia. Therefore, clinicians should consider the possibility of anaerobic coverage in the treatment of community-acquired empyema in the appropriate setting.

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Rapidly progressive empyema in the setting of vaping in an otherwise healthy patient

Vaping is defined as inhaling and exhaling vapour that is a product of heating a liquid or wax-like material. Electronic cigarettes (e-cigarettes) have become a popular method of smoking in the last decade and are advertised as an alternative to conventional smoking. Since the increase in e-cigarette use, various lung injury patterns have started to appear among users. Recent studies have shown an increased susceptibility to respiratory tract infections among e-cigarette/vaping product users. We present a case of pneumonia caused by Pseudomonas fluorescens complicated by rapidly developing empyema in an otherwise healthy patient.

Pleural Empyema Caused by Streptococcus intermedius and Fusobacterium nucleatum: A Distinct Entity of Pleural Infections

BACKGROUND

Many community-acquired pleural infections are caused by facultative and anaerobic bacteria from the human oral microbiota. The epidemiology, clinical characteristics, pathogenesis, and etiology of such infections are little studied. The aim of the present prospective multicenter cohort study was to provide a thorough microbiological and clinical characterization of such oral-type pleural infections and to improve our understanding of the underlying etiology and associated risk factors.

METHODS

Over a 2-year period, we included 77 patients with community-acquired pleural infection, whereof 63 (82%) represented oral-type pleural infections. Clinical and anamnestic data were systematically collected, and patients were offered a dental assessment by an oral surgeon. Microbial characterizations were done using next-generation sequencing. Obtained bacterial profiles were compared with microbiology data from previous investigations on odontogenic infections, bacteremia after extraction of infected teeth, and community-acquired brain abscesses.

RESULTS

From the oral-type pleural infections, we made 267 bacterial identifications representing 89 different species. Streptococcus intermedius and/or Fusobacterium nucleatum were identified as a dominant component in all infections. We found a high prevalence of dental infections among patients with oral-type pleural infection and demonstrate substantial similarities between the microbiology of such pleural infections and that of odontogenic infections, odontogenic bacteremia, and community-acquired brain abscesses.

CONCLUSIONS

Oral-type pleural infection is the most common type of community-acquired pleural infection. Current evidence supports hematogenous seeding of bacteria from a dental focus as the most important underlying etiology. Streptococcus intermedius and Fusobacterium nucleatum most likely represent key pathogens necessary for establishing the infection.

Severe pneumonia with empyema caused by Parvimonas micra and Streptococcus constellatus co-infection: a case report

Empyema is a common complication of pneumonia, caused by the accumulation of purulent exudate due to pathogenic bacteria invading the pleural cavity. Parvimonas micra and Streptococcus constellatus are pathogens that rarely cause pneumonia with empyema. Herein, a case of severe empyema caused by these two pathogens, confirmed by metagenomic next-generation sequencing (mNGS) of pleural effusion cultures, is reported. A male Chinese patient in his late sixties presented with wheezing, cough, sputum expectoration, and fever. Blood and sputum cultures were negative for pathogens, but the pleural effusion culture was positive for S. constellatus, and was also found to contain P. micra, confirmed by mNGS. The patient's symptoms improved after treatment with cefoperazone/sulbactam and moxifloxacin. Pneumonia caused by P. micra and S. constellatus is rare; however, coinfection with these pathogens may cause severe pneumonia, with or without empyema.

Culture-Negative Fusobacterium nucleatum Brain Abscess and Pleural Empyema Cases Revealed by 16S rRNA Sequencing

BACKGROUND

We reported two Fusobacterium nucleatum cases each of brain abscesses and pleural empyema, using 16S rRNA sequencing technology.

METHODS

We reviewed clinical records and microbiological findings in four patients with F. nucleatum infection.

RESULTS

All conventional culture results from peripheral blood, cerebrospinal fluid, and pleural fluid samples were found to be negative for this pathogen. Three patients were treated with antimicrobial agents for more than a week before specimen sampling. All patients recovered from their fusobacterial infections and were discharged.

CONCLUSIONS

Molecular identification methods such as 16S rRNA sequencing should accompany conventional culture to detect obligate anaerobic bacteria in deep-seated sites and organs.

Isolation and characterization of Buchananella hordeovulneris from feline pyothorax

A 1-year-old female mixed-breed cat was admitted to a veterinary hospital in Southern Brazil with tachypnea, low thoracic amplitude, restrictive breathing pattern, and cyanotic mucous membranes 2 days after elective castration surgery. Radiography revealed pleural effusion, and approximately 100-200 mL of fluid was collected by thoracocentesis. The reddish purulent exudate contained large numbers of yellowish-white granules with branched filamentous structures on cytological examination. The fluid was plated on blood agar and incubated under aerobiosis at 37 °C. On the third day of incubation, circular, dry, and opaque colonies, measuring < 0.5 mm in diameter, were observed. Their phenotypic and molecular characteristics were compatible with Buchananella hordeovulneris (basonym: Actinomyces hordeovulneris), a pathogenic actinomycete rarely detected in cats. Our findings indicate that B. hordeovulneris should be included in the differential diagnosis of pyothorax in cats together with Actinomyces spp. and Nocardia spp. Taxonomic confirmation of disease-causing microorganisms in animals is important to understand the course of infection and its association with disease epidemiology.

Novel case of empyema necessitans caused by Mycobacterium xenopi

Poorly controlled long-standing empyema can dissect through soft tissues and skin resulting in empyema necessitans. We present the first reported case of empyema necessitans caused by Mycobacterium xenopi, which was treated successfully with antimycobacterial therapy. The case highlights the indolent nature of the pathogen and the importance of an accurate diagnosis.

Management of Pediatric Thoracic Empyema in the North Queensland Region of Australia and Impact of a Local Evidence-based Treatment Guideline

AIM

The North Queensland region of Australia has a high incidence of pediatric thoracic empyema (pTE). We describe the management of empyema at the Townsville University Hospital which is the regional referral center for these children. The impact of a newly developed institutional guideline is also discussed.

METHODS

This retrospective audit included children under the age of 16 years treated for empyema between 1 Jan 2007 and 31 December 2018. Demographic and management-related variables were correlated to outcomes. A local guideline was introduced at the beginning of 2017 and patient outcomes characteristics pre, and post introduction of this guideline are compared.

RESULTS

There were 153 children with pTE (123 before and 30 after the introduction of a local guideline). Nonsurgical management was associated with a higher treatment failure rate. Median length of stay (LOS) was 11.8 (IQR 9.3-16) days. Longer hospital LOS was associated with younger age (r2 -0.16, P = 0.04), Aboriginal and/or Torres Strait (ATSI) ancestry (13.8 vs. 10.5 days, P = 0.002) and concomitant respiratory viral infections (14.4 vs. 10.9 days, P = 0.003). The introduction of local guideline was associated with significant decrease in the use of empirical chest CT scans (54.4% before vs. 6.7% after, P < 0.001) and duration of intravenous antibiotics (14 days before vs. 10 days after, P = 0.02). There was no significant change in the hospital LOS (12.1 days pre and 11.7 post, P = 0.8).

CONCLUSIONS

Younger age, concomitant viral respiratory infections and ATSI ancestry were identified as potential risk factors for increase LOS. Hospital LOS following the adoption of an institutional guideline was unchanged. However, such a guideline may identify populations at risk for an unfavorable course and avoid unnecessary antibiotic treatment and radiation exposure.

Effect of Prehospital Antibiotic Therapy on Clinical Outcome and Pathogen Detection in Children With Parapneumonic Pleural Effusion/Pleural Empyema

BACKGROUND

Parapneumonic pleural effusion and pleural empyema (PPE/PE) are complications of community-acquired pneumonia. The objective of this study was to analyze prehospital antibiotic therapy (PH-ABT) of children with PPE/PE and investigate its effects on clinical outcome and pathogen detection.

METHODS

Prospective nationwide active surveillance in Germany between October 2010 and June 2018. Children and adolescents <18 years of age with pneumonia-associated PE or PPE requiring drainage or with persistence of PPE/PE >7 days were included.

RESULTS

A total of 1724 children with PPE/PE were reported, of whom 556 children (32.3% of 1719 with available data) received PH-ABT. Children with PH-ABT had a shorter median hospital length of stay (15 vs. 18 days, P < 0.001), a longer time from onset of symptoms until hospital discharge (25 vs. 23 days, P = 0.002), a lower rate of intensive care unit admission (58.3% vs. 64.4%, P = 0.015) and fewer infectious complications (5.9% vs. 10.0%; P = 0.005). Bacterial pathogens in blood or pleural fluid culture were detected in 597 (34.5%) of 1513 children. Positive culture results were less frequent in children with than without PH-ABT (81/466 [17.4%] vs. 299/1005 [29.8%]; P < 0.001), whereas detection rates in pleural fluid samples by polymerase chain reaction were similar (91/181 [50.3%] vs. 220/398 [55.3%]; P = 0.263).

CONCLUSIONS

In children with PPE/PE, PH-ABT significantly reduced the overall rate of bacterial pathogen detection by culture, but not by polymerase chain reaction. PH-ABT was associated with a lower rate of infectious complications but did not affect the overall duration of disease. We therefore speculate that the duration of PPE/PE is mainly a consequence of an infection-induced inflammatory process, which can only partially be influenced by antibiotic treatment.

Polymicrobial etiology as a prognostic factor for empyema in addition to the renal, age, purulence, infection source, and dietary factors score

BACKGROUND

Empyema is an important and serious disease with high morbidity and mortality worldwide. However, the bacteriology and prognostic factors of empyema remain poorly understood, and data on the relationships among these parameters are scant.

METHODS

We retrospectively analyzed a prospectively collected database of patients with empyema admitted to Kurashiki Central Hospital, Japan, between May 2007 and September 2015. Only patients who had positive results on pleural fluid bacterial culture were included. We collected patient characteristics, bacteriology findings, treatments, and outcomes, and we assessed the prognostic factors for in-hospital mortality.

RESULTS

We included 71 patients in this study. The most commonly isolated bacteria were members of the Streptococcus anginosus group (37%), followed by anaerobes (30%). In-hospital mortality was 11%. On multivariate analysis, polymicrobial empyema (odds ratio [OR], 8.25; 95% confidence interval [CI], 1.08-62.90) and RAPID (renal, age, purulence, infection source, and dietary factors) score (OR, 6.89; 95% CI, 1.73-27.40) were significant risk factors for in-hospital mortality. The most common etiology of polymicrobial empyema was a combination of the members of the S. anginosus group and anaerobes, but no relationship was observed between the combination of microorganisms and outcomes. Although no significant difference was observed in treatment between the survivor and non-survivor groups, all patients who underwent surgery survived.

CONCLUSIONS

Members of the S. anginosus group and anaerobes were frequent pathogens in empyema, and polymicrobial etiology was independently associated with mortality in addition to the RAPID score. Surgery may be one option for preventing mortality.

REPORT-Pleural lavage of amphotericin B for treatment of empyema caused by Candida albicans infections: A case report

Chest fungal infection is a rarely seen lethal disease with rapid progression. Sufficient residence time of antifungal agent with therapeutic concentration in the chest is an essential point during anti-infection therapy, which is hard to achieve via conventional systemic drug delivery. We here by describe a case of successful treatment of fungal Chest infection via local pleural lavage. A 59 years old male was hospitalized due to chest pain. X-ray of chest and bacterial culture of thoracic drainage fluid and blood indicated severe chest infection of Candida albicans. The patient was initially administered intravenously with amphotericin B (25mg/day). However, the symptoms were not significantly improved after 5 days of treatment. Then one-hour pleural lavage of 5mg amphotericin B in volume of 50ml 5% glucose solution was added once daily. On day 12, bacterial cultures showed negative, and chest X-ray exhibited apparent decrease of shadow area, also other examinations such as body temperature and white blood cell count suggested significant improvement of infection. The therapeutic strategy of amphotericin B was maintained until two consecutive bacterial cultures were negative, then was switched back to intravenous drip alone for another one month found. No significant adverse effects were observed during the treatment. In conclusion, this case demonstrates a new local pleural lavage method of amphotericin B for chest fungal infection, which may provide a reference for the treatment of such cases.

Melioidosis, an emerging infectious disease in the Midwest Brazil: A case report

RATIONALE

Melioidosis is an emerging infectious disease in Brazil and caused by Burkholderia pseudomallei, with high morbidity and mortality rates. A total of 28 melioidosis cases were reported in Brazil until 2015. The majority of melioidosis cases were reported in the Northwest region of Brazil and such cases were not previously detected in the Midwest region of Brazil.

PATIENT CONCERNS

A 42-year-old man was admitted with a non-productive cough, dyspnea, myalgia, diffuse abdominal pain. Pulmonary auscultation revealed a vesicular murmur, snoring sounds, and the presence of basal crackling rales in the left hemithorax. The patient evolved with several respiratory failures and he was diagnosed as the first case of community-acquired pneumonia with sepsis caused by B pseudomallei in Mato Grosso do Sul, Midwest state of Brazil.

DIAGNOSIS

The cell isolates were subjected to 16S rRNA gene sequencing to confirm the bacterial species.

INTERVENTIONS

Administration of trimethoprim/sulfamethoxazole and meropenem stabilized the clinical condition of the patient. Subsequently upon discharge, the patient was also treated with trimethoprim/sulfametothoxazole for a year.

OUTCOME

We reported the first case of community-acquired pneumonia with sepsis caused by B pseudomallei in Mato Grosso do Sul, Midwest state of Brazil and the patient survived.

LESSONS

The emergence of melioidosis in the Midwest region is being neglected and underestimated and melioidosis must be considered of the differential diagnosis in community infections.

Detection of the major bacterial pathogens among children suffering from empyema in Ahvaz city, Iran

Introduction

Empyema is one of the important causes of pediatric hospital admissions.

Aim

In this study, we had investigated the frequency rates of S aureus, S pneumoniae, H influenzae, and P aeruginosa using PCR and bacterial culture among children suffering from empyema in Ahvaz city, Iran.

Methods

This was a descriptive study conducted on the patients hospitalized in ICUs of two teaching Hospitals of Ahvaz, Iran, between March and September 2018 on 105 pleural fluid (PF) samples of the children less than 16 years of age with the diagnosis of empyema thoracis. These specimens were inoculated on the bacterial culture media and identified using biochemical characteristics. Then, the existence of the four pathogens mentioned above was evaluated using PCR method.

Result

In this study, these bacteria agents were identified in 81 (77.14%) and 30 (28.57%) cases using the PCR assay and bacterial culture, respectively. Moreover, the PCR assay identified the infectious agents in 51 (68%) of PFs where the culture method failed. S pneumoniae (63 cases) was recognized as the most common pathogen, followed by P aeruginosa(19 cases), S aureus(15 cases), and H influenzae (9 cases) using the bacterial culture and PCR. Co‐infections were detected in 21 samples (20%) using PCR and one sample using the bacterial culture (P aeruginosa and S pneumoniae).

Conclusion

In this study, we found the higher frequencies of these microorganisms using PCR than culture. In addition, we showed that PCR was a sensitive and accurate method that unaffected by antibiotic therapy and could detect well co‐infections.

The great masquerade: Empyema thoracis as an unusual presentation of primary lung malignancy

Primary lung malignancy presenting as empyema is rare, with a reported incidence of 0.3%. We report a case of a 60- year-old man presenting with unilateral pleural effusion; diagnostic thoracocentesis confirmed Salmonella empyema. Post-drainage, chest radiograph showed persisting right hemithorax opacity; subsequent computed tomography revealed a right lung mass with right upper lobe bronchus obliteration. Percutaneous biopsy confirmed advanced stage lung adenocarcinoma. We discuss the mechanism of post-obstructive pneumonia in lung cancerassociated empyema and the utility of bedside ultrasound in diagnosis of lung masses. Clinicians are alerted to the possibility of lung malignancy in elderly patients presenting with empyema.

The bacterial aetiology of pleural empyema. A descriptive and comparative metagenomic study

OBJECTIVES

The view of pleural empyema as a complication of bacterial pneumonia is changing because many patients lack evidence of underlying pneumonia. To further our understanding of pathophysiological mechanisms, we conducted in-depth microbiological characterization of empyemas in clinically well-characterized patients and investigated observed microbial parallels between pleural empyemas and brain abscesses.

METHODS

Culture-positive and/or 16S rRNA gene PCR-positive pleural fluids were analysed using massive parallel sequencing of the 16S rRNA and rpoB genes. Clinical details were evaluated by medical record review. Comparative analysis with brain abscesses was performed using metagenomic data from a national Norwegian study.

RESULTS

Sixty-four individuals with empyema were included. Thirty-seven had a well-defined microbial aetiology, while 27, all of whom had community-acquired infections, did not. In the latter subset, Fusobacterium nucleatum and/or Streptococcus intermedius was detected in 26 patients, of which 18 had additional facultative and/or anaerobic species in various combinations. For this group, there was 65.5% species overlap with brain abscesses; predisposing factors included dental infection, minor chest trauma, chronic obstructive pulmonary disease, drug abuse, alcoholism and diabetes mellitus. Altogether, massive parallel sequencing yielded 385 bacterial detections, whereas culture detected 38 (10%) and 16S rRNA gene PCR/Sanger-based sequencing detected 87 (23%).

CONCLUSIONS

A subgroup of pleural empyema appears to be caused by a set of bacteria not normally considered to be involved in pneumonia. Such empyemas appear to have a similar microbial profile to oral/sinus-derived brain abscesses, supporting spread from the oral cavity, potentially haematogenously. We suggest reserving the term 'primary empyema' for these infections.

Streptococcus pneumoniae potently induces cell death in mesothelial cells

Pleural infection/empyema is common and its incidence continues to rise. Streptococcus pneumoniae is the commonest bacterial cause of empyema in children and among the commonest in adults. The mesothelium represents the first line of defense against invading microorganisms, but mesothelial cell responses to common empyema pathogens, including S. pneumoniae, have seldom been studied. We assessed mesothelial cell viability in vitro following exposure to common empyema pathogens. Clinical isolates of S. pneumoniae from 25 patients with invasive pneumococcal disease and three reference strains were tested. All potently induced death of cultured mesothelial cells (MeT-5A) in a dose- and time-dependent manner (>90% at 10⁷ CFU/mL after 24 hours). No significant mesothelial cell killing was observed when cells were co-cultured with Staphylococcus aureus, Streptococcus sanguinis and Streptococcus milleri group bacteria. S. pneumoniae induced mesothelial cell death via secretory product(s) as cytotoxicity could be: i) reproduced using conditioned media derived from S. pneumoniae and ii) in transwell studies when the bacteria and mesothelial cells were separated. No excess cell death was seen when heat-killed S. pneumoniae were used. Pneumolysin, a cytolytic S. pneumoniae toxin, induced cell death in a time- and dose-dependent manner. S. pneumoniae lacking the pneumolysin gene (D39 ΔPLY strain) failed to kill mesothelial cells compared to wild type (D39) controls, confirming the necessity of pneumolysin in D39-induced mesothelial cell death. However, pneumolysin gene mutation in other S. pneumoniae strains (TIGR4, ST3 and ST23F) only partly abolished their cytotoxic effects, suggesting different strains may induce cell death via different mechanisms.

A Retrospective Analysis of Anaerobic Bacteria Isolated in 236 Cases of Pleural Empyema and their Prevalance of Antimicrobial Resistance in Turkey

BACKGROUND

Parapneumonic effusions usually occur secondary to an infection and produce pus (empyema) that accumulates in the pleural space. We aimed to evaluate the prevalence of anerobes in patients with empyema and to assess their resistance patterns for seven antimicrobials.

METHODS

Pleural fluid specimens from 236 patients were inoculated on Schaedler agar. Anaerobic bacteria were identified via API 20 A. Susceptibility testing for penicillin, ampicillin + sulbactam, amoxicillin + clavulanate, cefoxitin, clindamycin, metronidazole, and imipenem were performed with the E-test.

RESULTS

There were 118 anaerobic bacterial strains detected in 66 (27.9%) of the 236 specimens. Gram-positive anaerobic cocci were detected in 54.23% and the predominant cocci were 41 Peptostreptococcus spp, (34.75%) followed by 17 P. acnes (14.41%) and 6 C. tertium (5.08%). The Gram-negative anaerobes were B. fragilis (28, 23.73%), P. melaninogenica (8, 6.78%), P. intermedia (4, 3.39%), F. nucleatum (6, 5.08%), F. mortiferum (5, 4.24%), and P. asaccharolytica (3, 2.54%). All anaerobic strains were susceptible to ampicillin + sulbactam, amoxicillin + clavulanate, and imipenem. The highest MIC was found to be > 256 µg/mL for penicillin in B. fragilis strains, 128 µg/mL for cefoxitin in P. melaninogenica strains, 32 µg/mL for clindamycin and 64 µg/mL for metronidazole in P. acnes strains. Clindamycin resistance was detected in 46.6% B. fragilis, and 17.6% for P. acnes. Thirty-eight (32.2%) strains produced beta-lactamase.

CONCLUSIONS

The use of antimicrobial agents for thoracic empyema should be based on the isolated pathogens and their resistance profiles. Clinicians should be aware of the wide diversity of anaerobic genera and species in cases of pleural empyema.