Aerobic and anaerobic microbiology of empyema. A retrospective review in two military hospitals

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.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Concomitant pyogenic spondylodiscitis and empyema following tongue cancer resection and wisdom tooth extraction: A case report and literature review

RATIONALE

Pyogenic spondylodiscitis is an infectious spinal disease that causes significant motor dysfunctions. Its diagnosis can be challenging owing to its rapid onset and nonspecific symptoms.

PATIENT CONCERNS

A 79-year-old Japanese man with a history of type 2 diabetes mellitus and polymyalgia rheumatica presented to our department with tongue pain. Following partial glossectomy and wisdom tooth extraction under general anesthesia, on 10 postoperative day (POD) the patient developed right-sided abdominal pain and difficulty in walking. On 12 POD, the patient was admitted to a municipal hospital due to respiratory distress and paraplegia.

DIAGNOSES

The patient was diagnosed with pyogenic spondylodiscitis and empyema. Blood tests revealed elevated C-reactive protein levels (36.5), white blood cell count (19,570), and neutrophil count (17,867).

INTERVENTIONS

The patient received meropenem hydrate 3 g/2 days as empiric antibiotic treatment for acute infection. Upon admission to the emergency department on 16 POD, the lung abscess was drained, hemilaminectomy was performed.

OUTCOMES

Blood cultures, sputum tests, and cultures from the thoracic and spinal abscesses drained during surgery revealed methicillin-sensitive Staphylococcus aureus. The infection was successfully managed, and the respiratory disturbance and inflammatory response improved. However, the lower half of the patient body remained paralyzed. Subsequently, the patient was transferred to a rehabilitation facility on 45 POD. The patient continued to undergo functional restoration training, gradually regained function, and eventually achieved the ability to walk with grasping gait.

LESSONS

This is the first case report of S aureus causing pyogenic spondylodiscitis and empyema due to blood stream infection from a post-oral surgical wound. Pyogenic spondylodiscitis arising from a secondary hematogenous infection is difficult to diagnose and can lead to severe functional impairment. Prompt and appropriate diagnosis and treatment based on detailed patient interviews, additional blood tests, and computed tomography are essential.

Role of Macrophage Colony-Stimulating Factor for Staphylococcal Infection in the Oral Cavity

OBJECTIVE

There are few valid indicators of oral infection owing to the complexity of pathogenic factors in oral diseases. Salivary markers are very useful for scrutinizing the symptoms of disease. To provide a reliable and useful predictive indicator of infection for opportunistic pathogens in individuals with compromised immune systems, such as those with periodontal diseases and Human Immunodeficiency Virus (HIV), this study examines opportunistic pathogens such as C. albicans and staphylococci and macrophage colony-stimulating factor (M-CSF) and CA125/MUC16 in saliva. The aim was to explore the correlations investigated among these factors.

METHODS

Samples were divided into two groups (based on patient sex, the absence and presence of dentures in elderly, or HIV-positive patients and healthy subjects), and the correlation was analyzed in two groups of elderly patients with periodontal disease (64.5 ± 11.2 years old) and HIV-infected patients (41.9 ± 8.4 years old). Healthy subjects (33.8 ± 9.1 years old) were also analyzed as a control. Levels of C. albicans, staphylococci, and M-CSF, which is an immunological factor for the differentiation of macrophage, and CA125/MUC16, which provides a protective lubricating barrier against infection, were investigated.

RESULTS

A significant and positive correlation between the levels of M-CSF and staphylococci was found in elderly individuals and HIV-positive patients treated with antiretroviral therapy. A significant and positive correlation between the levels of M-CSF and CD125/MUC16 was also found in both patients. These correlations were enhanced in both patients as compared with healthy subjects.

CONCLUSION

Salivary M-CSF might be useful as a new indicator of opportunistic infection caused by staphylococci and a defense against infection in immunocompromised hosts.

Case presentation of Campylobacter rectus leading to pneumonia and literature review

Pneumonia caused by Campylobacter rectus is very rare. Herein, we describe the treatment course and experiences of a patient with pneumonia caused by Campylobacter rectus. A 64-year-old woman with intermittent hemoptysis and part lung necrosis indicated by radiography was admitted to our hospital on March 15, 2021. After admission, a CT (Computer tomography)-guided percutaneous lung biopsy was identified as Campylobacter rectus positive by bacterial culture and metagenomic sequencing. The hemoptysis resolved, and the lesions in the right lower lung were gradually absorbed after treatment with anti-Campylobacter rectus drugs. In cases of pneumonia which unresolved by initial therapy and associated with more severe oral hygiene problems, the possibility of infection with oral pathogens (eg, Campylobacter rectus) should be considered. This case suggests that bacterial culture and metagenomic sequencing of the diseased tissue, particularly anaerobic culture, helps to clarify the etiological diagnosis.

Enterococcus faecium Empyema Following Extracorporeal Membrane Oxygenation for COVID-19 Acute Respiratory Distress Syndrome

A 33-year-old male with severe COVID-19 required prolonged veno-venous extracorporeal membrane oxygenation (ECMO) support. Following decannulation, he developed an Enterococcus faecium empyema. Tube thoracostomy and broad-spectrum antibiotics were initiated, followed by an unsuccessful attempt at pleural irrigation with saline, given the patient had an increased risk of bleeding due to the concomitant requirement for systemic anticoagulation. Subsequently, intrapleural tissue plasminogen activator (tPA) and recombinant human Dornase alfa (DNase) were safely administered with the resolution of empyema. Enterococcus faecium is an uncommon cause of pleural empyema and, to our knowledge, has not previously been reported to be associated with COVID-19 or ECMO.

Percutaneous management of complicated empyema thoracis using pigtail, report of a case from University Hospital of Nepal: a case report

Empyema thoracis is a condition characterized by the accumulation of pus in the pleural cavity of the lungs. Empyema thoracis is a cause of high mortality in man and its occurrence is increasing in both children and adults. Traditionally, chest tube drainage has been a preferred method of treatment, but recent studies have shown that pigtail catheter drainage is a more effective and less invasive alternative. Image-guided drainage is also preferred over blind drainage, and alternative drainage sites are being explored. These management changes have improved patient outcomes and reduced the risk of complications.

CASE PRESENTATION AND CLINICAL DISCUSSION

A 66-year-old female presented with complaints of cough, fever, and chest pain. A clinical examination was done and relevant investigations were sent. She was then treated in the line of left-sided empyema thoracis. A pigtail catheter was inserted into the loculated empyema via the left 9th intercostal space through a posterolateral approach with ultrasonography guidance.

CONCLUSION

The main aim of this article is to provide an overview of a rare management approach for empyema, a condition characterized by the accumulation of pus in the pleural cavity of the lungs. In this case report, the authors have focused on pigtail catheter drainage over traditionally performed chest tube drainage, and image-guided drainage has been performed over blind drainage ensuring accurate placement and reducing the risk of damage to surrounding tissues. Another notable change in empyema management is the shift in drainage sites from the safety triangle to other sites based on the site of loculations under ultrasonography guidance.

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.

Spontaneous Escherichia coli Empyema Thoracis: An Unusual Occurrence in a Non-cirrhotic, Immunocompetent Individual

Spontaneous bacterial empyema is a spontaneous infection of the pleural cavity in the absence of pneumonia, typically seen in patients with liver cirrhosis and preexisting hepatic hydrothorax. Empyema thoracis caused by Escherichia coli (E. coli) is a rare clinical finding and, in most cases, a consequence of E. coli pneumonia. Spontaneous bacterial empyema secondary to E. coli in a non-cirrhotic individual is an unusual association, rarely described in the literature. To the best of our knowledge, this is the first case of spontaneous bacterial E. coli empyema thoracis in a non-cirrhotic, immunocompetent individual with a complex medical history including pulmonary thromboembolism, oropharyngeal dysphagia, and a high aspiration risk of oropharyngeal secretions.

A challenging case of thoracic empyema caused by Prevotella spp

We report here the case of a 49-year-old man admitted for a diagnostic work-up of bilateral lung nodules. Empyema rapidly developed after a chest computed-tomodensitometry guided lung puncture. Despite the lack of obvious aetiology after two biopsies, the diagnosis was reached by performing 16S ribosomal DNA (rDNA) sequence analysis, which identified Prevotella spp in the pleural liquid. The empyema and lung nodules resolved after appropriate antibiotic therapy.

Diagnosis of pleural empyema/parapneumonic effusion by next-generation sequencing

BACKGROUND

Although a microbiological diagnosis of pleural infection is clinically important, it is often complicated by prior antibiotic treatment and/or difficulties with culturing some bacterial species. Therefore, we aimed to identify probable causative bacteria in pleural empyema/parapneumonic effusions by combining 16S ribosomal RNA (rRNA) gene amplification and next-generation sequencing (NGS).

METHODS

Pleural fluids were collected from 19 patients with infectious effusions and nine patients with non-infectious malignant effusions. We analysed DNA extracted from the pleural fluid supernatant by NGS using the Genome Search Toolkit and GenomeSync database, either directly or after PCR amplification of the 16S rRNA gene. Infectious and non-infectious effusions were distinguished by semi-quantitative PCR of the 16S rRNA gene.

RESULTS

Only 8 (42%) effusions were culture-positive, however, NGS of the 16S rRNA gene amplicon identified 14 anaerobes and 7 aerobes/facultative anaerobes in all patients, including Streptococcus sp. (n = 6), Fusobacterium sp. (n = 5), Porphyromonas sp. (n = 5), and Prevotella sp. (n = 4), accounting for >10% of the total genomes. The culture and NGS results were discordant for 3 out of 8 patients, all of whom had previously been treated with antibiotics. Total (2^ΔCT value in semi-quantitative PCR of the 16S rRNA gene) and specific (total bacterial load multiplied by the proportion of primary bacteria in NGS) bacterial loads could efficiently distinguish empyema/parapneumonic effusion from non-infectious effusion.

CONCLUSION

Combining NGS with semi-quantitative PCR can facilitate the diagnosis of pleural empyema/parapneumonic effusion and its causal bacteria.

Polymicrobial empyema; a novel case of Actinomyces turicensis

Empyema or infection of the pleural space is a well described complication of pneumonia, however knowledge of culprit pathogens is still evolving. We report a novel case of empyema due to Actinomyces turicensis, a commensal of the oropharynx and female urogenital tract but previously undescribed cause of empyema. We additionally review general pathogenesis of Actinomyces species within the pleural space. Familiarity with this unique pleural infection pathogen is important for selection of adequate antimicrobial therapy given the propensity of anaerobes such as Actinomyces species to disobey anatomic boundaries and recrudescence of infection in the absence of appropriate therapy.

Oxygen and Metabolism: Digesting Determinants of Antibiotic Susceptibility in the Gut

Microbial metabolism is a major determinant of antibiotic susceptibility. Environmental conditions that modify metabolism, notably oxygen availability and redox potential, can directly fine-tune susceptibility to antibiotics. Despite this, relatively few studies have discussed these modifications within the gastrointestinal tract and their implication on in vivo drug activity and the off-target effects of antibiotics in the gut. In this review, we discuss the environmental and biogeographical complexity of the gastrointestinal tract in regard to oxygen availability and redox potential, addressing how the heterogeneity of gut microhabitats may modify antibiotic activity in vivo. We contextualize the current literature surrounding oxygen availability and antibiotic efficacy and discuss empirical treatments. We end by discussing predicted patterns of antibiotic activity in prominent microbiome taxa, given gut heterogeneity, oxygen availability, and polymicrobial interactions. We also propose additional work required to fully elucidate the role of oxygen metabolism on antibiotic susceptibility in the context of the gut.

Surgical outcome of empyema thoracis patients with special correlation to pre-operative contrast-enhanced computerized tomography (CECT) thorax morphometry

Purpose

Empyema thoracis is a very common disease. The surgical outcome of empyema patients depends upon various factors. To the best of our knowledge, there is no study in literature describing the surgical outcome of patients in relation to the contrast-enhanced computerized tomography (CECT) thorax morphometric findings. In this study, we examined the surgical outcome of empyema thoracis patients in relation to both clinical and radiological findings.

Materials and methods

It is a prospective hospital-based study conducted between October 2016 and August 2018. A total of 30 patients, who underwent decortication during the study period, were included. They were divided into three performance groups (excellent performance, average performance and poor performance groups) according to the outcome. The surgical outcome was correlated with the pre-operative clinical, radiological, intra-operative and post-operative parameters.

Results

Intra-operative ability to complete decortication, intra-operative expansion of the lungs and presence of broncho-pleural fistula were significantly different between the three performance groups. Duration of the disease, pre-operative duration of antitubercular therapy (ATT) intake and duration of pre-operative intercostal drain (ICD) were statistically insignificant between groups. In computed tomography (CT) morphometry, residual lung volume of the involved lung and volume of empyema were found to be significantly different between the performance groups. The residual volume of the involved lung (expressed in terms of the percentage of lung volume of the normal opposite lung) can predict the complete expansion of the lung with sensitivity of 71% and specificity of 70%.

Conclusion

The pre-operative residual lung volume of the involved lung, empyema volume, completeness of decortication, intra-operative expansion of the lung and presence or absence of broncho-pleural fistula can determine the surgical outcome in empyema thoracis patients.

Antibiotic Resistance Is Associated With Morbidity and Mortality After Decortication for Empyema

BACKGROUND

Previous studies of decortication for empyema demonstrated that patient characteristics are associated with mortality, but the relationship of infectious pathogen to outcome has not been described. Our objective was to analyze the association of microbiology and antibiotic resistance with postoperative mortality after decortication for empyema. We hypothesized that bacterial pathogens, antibiotic resistance, and patient characteristics would all contribute to perioperative morbidity and mortality.

METHODS

Patients undergoing pulmonary decortication for empyema from January 1, 2010 to October 1, 2017 were reviewed retrospectively. Cases were matched with microbiology cultures. Outcomes of interest were a composite of death, tracheostomy, initial ventilator support greater than 48 hours, or unexpected intensive care unit readmission. Antibiotic resistance was categorized as present or absent, and the number of antibiotics with resistance was counted for each patient. We describe the relationship of patient characteristics, antibiotic resistance, and microbiology to mortality.

RESULTS

During the study period, 185 patients underwent decortication, 118 of whom had a diagnosis of primary empyema (63.8%). Positive culture results were present in 79 of 185 patients (43%). The most common isolate was Streptococcus, which was present in 29 of 79 (37%), followed by Staphylococcus in 19 of 79 (24%). Of 79 patients, 11 had fungal infections (13.9%). In addition, 16 of 79 patients had polymicrobial empyema (20%). Of 185 patients, 30 experienced the composite adverse outcome (16.2%). In multivariable regression, the composite adverse outcome was associated with emphysema, Candida in pleural culture, and antibiotic resistance count.

CONCLUSIONS

Perioperative mortality and morbidity after decortication for empyema is considerable. In this cohort, infections with increasing antibiotic resistance are associated with morbidity and mortality among patients with empyema.

Change in Pulmonary Function Following Decortication for Chronic Pleural Empyema

OBJECTIVES

Chronic empyema is the final stage of the triphasic pathogenesis of empyema that is characterized by fibrin deposits in both pleural surfaces, leading to the formation of a thickened pleural peel. This restricts the lung movements, giving rise to a trapped lung and impairment of pulmonary function. The aim of this study was to determine the change in pulmonary function following decortication for chronic empyema.

MATERIALS AND METHODS

A total of 35 patients with chronic pleural empyema who underwent decortication via a posterolateral thoracotomy between July 2016 and July 2017 were reviewed and followed-up for 6±3 months after surgery. All patients underwent a pulmonary function test using spirometry before and after surgery. Pre-operation spirometry values [mean forced expiratory volume in 1s (FEV₁) and mean forced vital capacity (FVC)] were compared with the post-operation data obtained during follow-up and the change was quantified by statistical analysis.

RESULTS

FEV₁ was 70.51% before surgery vs. 83.43% after surgery (p<0.001). FVC was 69.74% before surgery vs. 85.40% after surgery (p<0.001). There was no influence of bacteriology, side of occurrence of the lesion, smoking habit, or diabetes mellitus present before the operation on the patients' lung function (p>0.01).

CONCLUSION

Decortication and pleurectomy via a posterolateral thoracotomy resulted in significant clinico-functional improvement in patients with chronic empyema, regardless of the bacteriology, side of occurrence of the lesion, smoking habit, or diabetic status of the patient.

New perspectives in aspiration community acquired Pneumonia

Introduction: Aspiration pneumonia is a subclass of community-acquired pneumonia that is expected to have an increasing contribution in mortality and morbidity, particularly in the elderly population over the next coming decades. While studies have revealed significant progress in identifying risk factors for aspiration pneumonia, the clinical presentation and diagnosis remain challenging to healthcare providers. Areas covered: We conducted a broad literature review using the MeSH heading in PubMed/MEDLINE of 'aspiration pneumonia' from January 1970 to July 2019. The understanding of the microbiology of aspiration pneumonia has evolved from a possible shift in the causative organisms away from anaerobes to traditional community-acquired pneumonia organisms. The importance of this shift is not yet known, but it has questioned the pathogenic role of anaerobes, appropriate anaerobic testing and the role of these pathogens in the pulmonary microbiome in patients with pneumonia. The identification of risk factors led to strategies to prevent or minimize the risk of aspiration pneumonia with moderate success. Expert opinion: Our expert opinion is that further research is needed to determine the role of the microbiome with aspiration pneumonia and patient risk factors. There is also a great need to develop clinical tools to help providers diagnose, treat, and prevent aspiration pneumonia.

Post-resection complications: abscesses, empyemas, bronchopleural fistulas

The role of thoracic surgeons in the management of pulmonary infection has evolved over time as the medical treatments have improved. We herein review historical and current management for surgically-treated pulmonary infections-lung abscesses, empyemas, and bronchopleural fistulas. In particular, we review when the surgeons need to be involved for infectious cases, our algorithm/approach to empyemas, and summary of post-operative bronchopleural fistula in tuberculosis cases.

Vancomycin-resistant Enterococcus faecium Empyema in an Asplenic Patient

Enterococcal empyema is a rare complication of pneumonia. We report the case of a 67-year-old asplenic man with pneumonia complicated by respiratory failure and empyema requiring decortication and prolonged chest tube drainage. Cultures of the empyema were initially negative, but later grew vancomycin-resistant Enterococcus faecium (VRE), which was successfully treated with linezolid. To our knowledge, this is only the second reported case of an empyema caused by VRE that was not associated with an intra-abdominal infection. We suspect superinfection due to airway or chest tube contamination as the most likely mechanism of infection. Physicians should consider multi-drug resistant organisms such as VRE in patients with empyema that fail to resolve with chest tube drainage and broad-spectrum antibiotics.

A portable system for rapid bacterial composition analysis using a nanopore-based sequencer and laptop computer

We developed a portable system for 16S rDNA analyses consisting of a nanopore technology-based sequencer, the MinION, and laptop computers, and assessed its potential ability to determine bacterial compositions rapidly. We tested our protocols using a mock bacterial community that contained equimolar 16S rDNA and a pleural effusion from a patient with empyema, for time effectiveness and accuracy. MinION sequencing targeting 16S rDNA detected all 20 of the bacterial species present in the mock bacterial community. Time course analysis indicated that the sequence data obtained during the first 5 minutes of sequencing (1,379 bacterial reads) were enough to detect all 20 bacteria in the mock sample and to determine species composition, consistent with results of those obtained from 4 hours of sequencing (24,202 reads). Additionally, using a clinical sample extracted from the empyema patient's pleural effusion, we could identify major bacterial pathogens in that effusion using our rapid sequencing and analysis protocol. All results are comparable to conventional 16S rDNA sequencing results using an IonPGM sequencer. Our results suggest that rapid sequencing and bacterial composition determination are possible within 2 hours after obtaining a DNA sample.

Community Acquired Pneumonia

Early identification of patients with severe community-acquired pneumonia (CAP) who require ICU care is important as delayed transfer is associated with increased mortality. In such patients, aggressive diagnostic testing is warranted given the increased probability of detecting a pathogen resistant to usual empirical therapy. In the absence of risk factors for healthcare-associated pneumonia or drug resistant pathogens, adequate coverage of Streptococcus pneumoniae and Legionella pneumophila is crucial. When Pseudomonas is suspected, dual anti-pseudomonal therapy is required. When methicillin-resistant Staphylococcus aureus is suspected, linezolid is superior to vancomycin.

Several aspects of managing severe CAP remain without consensus and include the risks associated with multidrug resistant pathogens, antibiotic use to suppress toxin formation in the setting of pneumonia caused by S. aureus, and adjuvant assessment tools such as procalcitonin.

Pleural effusions in non-transplanted cystic fibrosis patients

BACKGROUND

Pleural effusions are considered rare in cystic fibrosis (CF) patients. There is a paucity of available information in the literature concerning the nature and significance of pleural effusions in non-transplanted CF patients.

METHODS

We conducted a multicenter retrospective evaluation of non-transplanted adult CF patients. Given the small sample size, only descriptive statistics were performed.

RESULTS

A total of 17 CF patients with pleural effusion were identified, of whom 9 patients underwent thoracentesis. The crude incidence of pleural effusion was 43 per 10,000 person-years in hospitalized CF patients at large CF centers. All sampled effusions were inflammatory in nature. All samples submitted for culture grew at least one organism.

CONCLUSION

Pleural effusions are rare in adult non-transplanted CF patients. These fluid collections appear to be quite inflammatory with a higher rate of empyema than in the general population.

Thoracic empyema caused by Campylobacter rectus

We report a case of thoracic empyema caused by Campylobacter rectus, an organism considered as a periodontal pathogen but rarely recovered from extraoral specimens. The patient fully recovered through drainage of purulent pleural fluid and administration of antibiotics. The present case illustrates that C. rectus can be a cause of not only periodontal disease but also pulmonary infection.

Bad news itself or just the messenger? The high mortality of Fusobacterium spp. infections is related to disseminated malignancy and other comorbidities

BACKGROUND

Fusobacterium species are pleomorphic, obligate anaerobic gram-negative bacilli. They are difficult to culture and grow slowly. If antibiotic treatment is initiated prior to blood cultures, the bacteria might evade detection. This is a comprehensive report on mortality in non-bacteraemia fusobacterial infection.

METHODS

Data were collected retrospectively in adults having a positive culture with Fusobacterium spp. admitted during 2000-2012 at the medical department. Data on culture specimens, number of cultures, admission and culture dates, patient age, gender, clinical disease, Charlson's index of co-morbidity, CRP level and survival were obtained. For comparison, we traced 60 consecutive, similarly obtained cultures from 2009 to 2010 containing Staphylococcus aureus.

RESULTS

Within a 12-year period, we identified 28 patients with a positive culture of Fusobacterium spp. in a medical ward serving a population of 220,000. Only a minority (39%) had a positive blood culture, and 54% had focus in respiratory tract or pleura. Overall 6-month mortality was 32%, and unrelated to subspecies, treatment or anatomic location but significantly related to age >60 years, admission for severe, acute illness, and comorbidity, especially metastatic malignancy. Comparison between infection with Fusobacterium spp. and S. aureus showed that Fusobacterium spp. infections were predominantly community acquired, while S. aureus were both community and hospital acquired. Overall mortality for both bacterial infections increased significantly with age and current malignant disease. S. aureus-infected patients carried a significantly higher mortality.

CONCLUSION

Our data support that Fusobacterium spp. infection is a marker for significant, chronic disease rather than carrying a poor prognosis per se.

Empyema management: A cohort study evaluating antimicrobial therapy

OBJECTIVES

Empyemas require aggressive antimicrobial and surgical management. However, the specifics of antimicrobial therapy have not been studied in clinical trials. The present study examines management and outcomes among a cohort of patients with empyema cared for in a tertiary-care referral hospital over a decade.

METHODS

We retrospectively identified patients hospitalized with empyema from January 2000 through December 2010 at one institution. Patient demographics, laboratory findings, treatments, and patient outcomes were abstracted using a standard form. Data were summarized with standard descriptive statistics.

RESULTS

A total of 91 patients were identified. The predominant organisms were viridans group streptococci, which were isolated in 64% of cases with cultures. The median length of hospitalization was 9 days. Length of antimicrobial therapy from time of source control was variable, with a median (interquartile range) duration of 27 (15-31) days. Of note, longer courses of parenteral, but not oral, therapy were associated with fewer cases of clinical failure.

CONCLUSIONS

This descriptive analysis demonstrated a higher rate of viridans group streptococci than expected. Three weeks of therapy was generally adequate and prevented clinical failure, but further study is needed with a much larger cohort to better define the optimal drug regimen, route, and duration of antimicrobial therapy for empyema.

Clinical characteristics and outcomes of patients with community-acquired, health-care-associated and hospital-acquired empyema

BACKGROUND AND AIMS

Patients with pneumonia, a common cause of empyema, are stratified based on their risk factors, and the treatment of empyema might benefit from this risk stratification.

METHODS

The etiology, bacteriologic profile and outcome of patients diagnosed with empyema in Shinko Hospital between May 2005 and October 2013 were retrospectively studied. The patients were stratified according to whether they had community-acquired empyema (CAE), health-care-associated empyema (HCAE) or hospital-acquired empyema (HAE).

RESULTS

The study included 81 patients, 25 CAE, 40 HCAE and 16 HAE. The comorbidity rate was highest among HAE patients (100%), followed by 95% of HCAE and 72% of CAE patients (P = 0.005). The rates of cancer and central nervous system (CNS) disease were higher in patients with HCAE and HAE than in patients with CAE (P = 0.030, P = 0.018, respectively). Pleural fluid cultures were positive in 58/81 patients. Streptococcus species were the most common organisms cultured from CAE (12/15) and HCAE patients (17/30), but not from HAE patients (3/13). Anaerobic organisms were cultured from 3 CAE, 5 HCAE and 3 HAE patients. Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa were only cultured from HCAE and HAE patients. The mortality rates were higher in HCAE (18%) and HAE (50%) than in CAE (4%) patients (log-rank test: P = 0.0012).

CONCLUSIONS

Half of patients with empyema were HCAE patients, who had comorbidities, bacteriological profile and outcome different from CAE patients. The patient with HCAE should be differentiated from CAE patient, and the stratification of patients based on risk factors may be useful for treatment strategy.

Spectrum and treatment of anaerobic infections

Anaerobes are the most predominant components of the normal human skin and mucous membranes bacterial flora, and are a frequent cause of endogenous bacterial infections. Anaerobic infections can occur in all body locations: the central nervous system, oral cavity, head and neck, chest, abdomen, pelvis, skin, and soft tissues. Treatment of anaerobic infection is complicated by their slow growth in culture, by their polymicrobial nature and by their growing resistance to antimicrobials. Antimicrobial therapy is frequently the only form of therapy needed, whereas in others it is an important adjunct to drainage and surgery. Because anaerobes generally are isolated mixed with aerobes, the antimicrobial chosen should provide for adequate coverage of both. The most effective antimicrobials against anaerobes are: metronidazole, the carbapenems (imipenem, meropenem, doripenem, ertapenem), chloramphenicol, the combinations of a penicillin and a beta-lactamase inhibitors (ampicillin or ticarcillin plus clavulanate, amoxicillin plus sulbactam, piperacillin plus tazobactam), tigecycline, cefoxitin and clindamycin.

Simple Pneumonia or Something More?: A Case Report and Discussion of Unexpected Empyema Identified by Point-of-Care Ultrasound

There is evidence to suggest that point-of-care ultrasound assessment of the lungs has a higher sensitivity and specificity than chest radiography for the diagnosis of pneumonia. It is unknown if the same is true for pneumonia complications. We present and discuss the case of a 61-year-old woman who presented to the emergency department with confusion, decreased level of consciousness, and signs of sepsis. A chest x-ray revealed a right sided infiltrate. An ultrasound of the patient's lungs was performed, and revealed a complex loculated fluid collection consistent with an empyema. A chest CT confirmed the diagnosis, and immediate percutaneous drainage was performed.

Pneumonia and empyema: causal, casual or unknown

Parapneumonic effusions complicating pneumonia are associated with increased morbidity and mortality. Along with increased mortality, complicated parapneumonic effusion and empyema often necessitate prolonged treatment, longer hospital stay and interventions. Parapneumonic effusions arise from inflammation in the lungs and pleural space from direct invasion of bacteria, cascade of inflammatory events and bacteriologic virulence features. Patient factors and comorbidities also contribute to the pathophysiology of parapneumonic effusion development. The evolution of parapneumonic effusion can be divided into three progressive stages: (I) exudative stage; (II) fibrinopurulent stage; and (III) organizing stage with pleural peel formation. These stages can help categorize effusions into groups in order to evaluate the risk of a complicated course requiring intervention. We recommend that clinical data be evaluated and a stepwise approach be taken in management of these patients. This review article discusses current understanding of the development and relationship of parapneumonic effusions with pneumonia.

[Parapneumonic pleural effusions: Epidemiology, diagnosis, classification and management]

Parapneumonic pleural effusions represent the main cause of pleural infections. Their incidence is constantly increasing. Although by definition they are considered to be a "parapneumonic" phenomenon, the microbial epidemiology of these effusions differs from pneumonia with a higher prevalence of anaerobic bacteria. The first thoracentesis is the most important diagnostic stage because it allows for a distinction between complicated and non-complicated parapneumonic effusions. Only complicated parapneumonic effusions need to be drained. Therapeutic evacuation modalities include repeated therapeutic thoracentesis, chest tube drainage or thoracic surgery. The choice of the first-line evacuation treatment is still controversial and there are few prospective controlled studies. The effectiveness of fibrinolytic agents is not established except when they are combined with DNase. Antibiotics are mandatory; they should be initiated as quickly as possible and should be active against anaerobic bacteria except for in the context of pneumococcal infections. There are few data on the use of chest physiotherapy, which remains widely used. Mortality is still high and is influenced by underlying comorbidities.

[Pleural effusion: diagnosis and management]

Pleural effusion management is a common clinical situation associated with numerous pulmonary, pleural or extra-pulmonary diseases. A systematic approach is needed to enable a rapid diagnosis and an appropriate treatment. Pleural fluid analysis is the first step to perform which allows a presumptive diagnosis in most cases. Otherwise, further analysis of the pleural fluid or thoracic imaging or pleural biopsy may be necessary. This review aims at highlighting the important elements of the work-up required by a pleural effusion.

Empyema caused by Prevotella bivia complicating an unusual case of spontaneous chylothorax

Spontaneous chylothorax is rare in adults. We present an unusual case that was complicated by Prevotella bivia empyema. Full recovery was achieved with chest tube drainage and prompt treatment with intravenous clindamycin.

Closure of a broncho-pleural fistula using an atrial septal defect occluder

Broncho-pleural fistulae (BPF) are recognised as a rare complication following pneumonectomy. We describe a patient, who after failing conservative treatment, underwent closure of a persistent fistula with an atrial septal defect (ASD) occluder. Additionally we review the literature regarding management of BPF and the emerging role of cardiac defect closure devices as a possible treatment option.

Anaerobes in nosocomial and community acquired pleural infections

Anaerobes are important causes of pleural space infections. The aim of the study is to evaluate the role of the anaerobic bacteria in pleural infections. The study involved 278 consecutive clinical samples sent to the Clinical Microbiology Laboratory of Tertiary Chest Hospital. Anaerobes were isolated in 39 community acquired and five nosocomial cases out of 278 anaerobic cultivations (15.8%). Total of 56 anaerobe strains were identified and 21 aerobes were accompanied to anaerobic isolates. Aerobe isolates were associated with anaerobic microorganisms in 19 cases (43.2%). Bacteroides species (21.4%) and Pseudomonas aeruginosa (33.3%) were the most common anaerobic and aerobic isolates.

How important are anaerobic bacteria in aspiration pneumonia: when should they be treated and what is optimal therapy

Anaerobic bacteria are infrequent pulmonary pathogens, and, even then they are, they are almost never recovered due to the need for specimens uncontaminated by the upper airway flora and failure to do adequate anaerobic bacteriology. These bacteria are relatively common in selected types of lung infections including aspiration pneumonia, lung abscess, necrotizing pneumonia and emphyema. Preferred antibiotics for these infections based on clinical experience are clindamycin and any betalactam-betalactamase inhibitor.

Pleural infections: a 9-year review of bacteriology, case characteristics and mortality

BACKGROUND

Despite advances in medical therapies, pleural infections remain a common disease. The characteristics of this disease seem to change over time, with alterations in patient characteristics and bacteriology. The purpose of this study was to provide a retrospective descriptive analysis of pleural infections during a 9-year period.

METHODS

We performed a single-center retrospective review of all culture-positive pleural infections between January 2000 and December 2008. The primary outcome was assessment of long-term survival and associated independent risk factors affecting survival. Length of survival was determined using the Social Security Death Index. Case characteristics and bacteriology were reviewed for descriptive analysis.

RESULTS

During a 9-year period, 187 culture-positive pleural infections were identified. Review of bacteriology revealed gram-positive cocci as the predominate organisms, most commonly Streptococcus and Staphylococcus. Anaerobes were found in 9.1% of the cases. Independent risk factors associated with risk of death based on multivariable survival analysis were age older than 65, cirrhosis and past and present malignancy. The hospital mortality was 10.7%, and the 1-year, 3-year and 5-year estimated survival rates were 73.8%, 63.3% and 60.6%, respectively.

CONCLUSIONS

Pleural infections continue to remain a major health problem and carry significant morbidly and mortality. The importance of Staphylococcus aureus in this population has yet to be fully examined, and although potentially underestimated in this study, anaerobic infections remain a common pathogen.

Gram-positive anaerobic cocci--commensals and opportunistic pathogens

Among the Gram-positive anaerobic bacteria associated with clinical infections, the Gram-positive anaerobic cocci (GPAC) are the most prominent and account for approximately 25-30% of all isolated anaerobic bacteria from clinical specimens. Still, routine culture and identification of these slowly growing anaerobes to the species level has been limited in the diagnostic laboratory, mainly due to the requirement of prolonged incubation times and time-consuming phenotypic identification. In addition, GPAC are mostly isolated from polymicrobial infections with known pathogens and therefore their relevance has often been overlooked. However, through improvements in diagnostic and in particular molecular techniques, the isolation and identification of individual genera and species of GPAC associated with specific infections have been enhanced. Furthermore, the taxonomy of GPAC has undergone considerable changes over the years, mainly due to the development of molecular identification methods. Existing species have been renamed and novel species have been added, resulting in changes of the nomenclature. As the abundance and significance of GPAC in clinical infections grow, knowledge of virulence factors and antibiotic resistance patterns of different species becomes more important. The present review describes recent advances of GPAC and what is known of the biology and pathogenic effects of Anaerococcus, Finegoldia, Parvimonas, Peptoniphilus and Peptostreptococcus, the most important GPAC genera isolated from human infections.

Spontaneous bacterial empyema

PURPOSE OF REVIEW

Spontaneous bacterial empyema (SBEM) is defined as spontaneous infection of a preexisting hepatic hydrothorax. SBEM is diagnosed after exclusion of pneumonia, and, in patients with liver cirrhosis, it is still associated with significant morbidity and mortality. To date, studies focusing on SBEM are rare. This review will highlight the recent data focusing on the clinical characteristics, bacteriology, management, and outcome predictors of cirrhotic patients with SBEM.

RECENT FINDINGS

The Enterobacteriaceae (Escherichia coli and Klebsiella pneumoniae) are the major causative pathogens isolated from SBEM patients. Therefore, the cornerstone of therapy is antibiotic therapy with immediate empirical use of third-generation cephalosporins as first-line treatment. Chest-tube placement is not necessary. Regression analysis identified three independent factors related to poor outcome: high score of the model for end-stage liver disease-sodium (MELD-Na), initial ICU admission, and initial antibiotic treatment failure. High MELD-Na score may be a useful predictor of SBEM mortality in cirrhotic patients.

SUMMARY

Although SBEM is a rare complication of cirrhosis, the high mortality rate should increase physicians' index of suspicion in cirrhotic patients with hydrothorax and prompt immediate diagnostic thoracentesis. The MELD-Na score rather than Child-Pugh score may be a strong predictor of in-hospital mortality of SBEM patients.

Management of infectious processes of the pleural space: a review

Pleural effusions can present in 40% of patients with pneumonia. Presence of an effusion can complicate the diagnosis as well as the management of infection in lungs and pleural space. There has been an increase in the morbidity and mortality associated with parapneumonic effusions and empyema. This calls for employment of advanced treatment modalities and development of a standardized protocol to manage pleural sepsis early. There has been an increased understanding about the indications and appropriate usage of procedural options at clinicians' disposal.

Infection with human coronavirus NL63 enhances streptococcal adherence to epithelial cells

Understanding the mechanisms of augmented bacterial pathogenicity in post-viral infections is the first step in the development of an effective therapy. This study assessed the effect of human coronavirus NL63 (HCoV-NL63) on the adherence of bacterial pathogens associated with respiratory tract illnesses. It was shown that HCoV-NL63 infection resulted in an increased adherence of Streptococcus pneumoniae to virus-infected cell lines and fully differentiated primary human airway epithelium cultures. The enhanced binding of bacteria correlated with an increased expression level of the platelet-activating factor receptor (PAF-R), but detailed evaluation of the bacterium-PAF-R interaction revealed a limited relevance of this process.

Empyema thoracis

Epmyema thoracis is associated with high mortality ranging between 6% to 24%. The incidence of empyema is increasing in both children and adults; the cause of this surge is unknown. Most cases of empyema complicate community- or hospital-acquired pneumonia but a proportion results from iatrogenic causes or develops without pneumonia. Parapneumonic effusions (PPE) develop in about one half of the patients hospitalized with pneumonia and their presence cause a four-fold increase in mortality. Three stages in the natural course of empyema have long been described: the exudative, fibrinopurulent, and organizing phases. Clinically, PPE are classified as simple PPE, complicated PPE, and frank empyema. Simple PPE are transudates with a pH > 7.20 whereas complicated PPE are exudates with glucose level <2.2 mmol/l and pH < 7.20. Two guidelines statements on the management of PPE in adults have been published by the American College of Chest Physicians (ACCP) and the British Thoracic Society (BTS). Although they differ in their approach on how to manage PPE, they agree on drainage of the pleural space in complicated PPE and frank empyema. They also recommend the use of intrapleural fibrinolysis and surgical intervention in those who do not show improvement, but the level of evidence for the use of intrapleural fibrinolysis is not high highlighting the need for more research in this area. A recently published large randomized trial has shown no survival advantage with the use of intrapleural streptokinase in patients with pleural infection. However, streptokinase enhances drainage of infected pleural fluid and may still be used in patients with large collection of infected pleural fluid causing breathlessness or ventilatory failure. There is emerging evidence that the combination of intrapleural tPA/DNase is significantly superior to tPA or DNase alone, or placebo in improving pleural fluid drainage in patients with pleural space infection. A guideline statement on the management of PPE in children has been published by the BTS. It recommends the use of antibiotics in all patients with PPE in addition to either video-assisted thoracoscopic surgery (VATS) or tube thoracostomy and intrapleural fibrinolysis. Prospective randomized trials have shown that intrapleural fibrinolysis is as effective as VATS for the treatment of childhood empyema and is a more economic treatment and therefore, should be the primary treatment of choice.