Etiology and outcome of community-acquired lung abscess

Aspiration Pneumonia

Aspiration pneumonia is a lower respiratory tract infection that results from inhalation of foreign material, often gastric and oropharyngeal contents. It is important to distinguish this from a similar entity, aspiration with chemical pneumonitis, as treatment approaches may differ. An evolving understanding of the human microbiome has shed light on the pathogenesis of aspiration pneumonia, suggesting that dysbiosis, repetitive injury, and inflammatory responses play a role in its development. Risk factors for aspiration events involve a complex interplay of anatomical and physiological dysfunctions in the nervous, gastrointestinal, and pulmonary systems. Current treatment strategies have shifted away from anaerobic organisms as leading pathogens. Prevention of aspiration pneumonia primarily involves addressing oropharyngeal dysphagia, a significant risk factor for aspiration pneumonia, particularly among elderly individuals and those with cognitive and neurodegenerative disorders.

Frontal Sinus Mucosa Bacteriological Features: Evaluation after Unintentional Opening in Neurosurgery

Objectives  The bacteriological features of the frontal sinus mucosa may impose significant complications in neurosurgery, when breached unintentionally. This study aimed to investigate the bacterial flora in patients undergoing frontal craniotomy for cerebrovascular substrate surgery. Design  This is a single-center prospective study. Setting  When mucosal laceration occurred, the patients underwent frontal sinus reconstruction with mucosa reconstruction, preserving the nasofrontal duct. Participants  We enrolled eight consecutive patients who underwent bifrontal craniotomy associated with frontal sinus mucosa laceration. Main Outcome Measures  A portion of the mucosa was extracted during the reconstructive procedure and was sent for microbiological analysis. Results  None of the patients presented with the bacterial flora in the mucosal cultures. No patient experienced postoperative cerebrospinal fluid leakage or meningitis. One patient with a clinical history of chronic maxillary sinusitis presented with a subcutaneous abscess around the forehead at 9 months postoperatively. The patient rapidly recovered after receiving oral administration of antibiotics. Conclusions  Our findings demonstrated that the frontal sinuses were maintained in an aseptic environment in all cases. The results may encourage the development and wider use of transfrontal sinus approaches.

Vacuum-assisted closure for chest wall reconstruction infection caused by Streptococcus mitis after surgery of lung cancer: a case report

BACKGROUND

Among a cohort of patients who underwent chest wall resection and reconstruction by rigid prosthesis, 6% required removal of the prosthesis, and in 80% of these cases the indication for prosthesis removal was infection. Although artificial prosthesis removal is the primary approach in such cases of infection, the usefulness of vacuum-assisted closure (VAC) has also been reported.

CASE PRESENTATION

A 64-year-old man with diabetes mellitus underwent right middle and lower lobectomy with chest wall (3rd to 5th rib) resection and lymph node dissection because of lung squamous cell carcinoma. The chest wall defect was reconstructed by an expanded polytetrafluoroethylene (PTFE) sheet. Three months after surgery, the patient developed an abscess in the chest wall around the PTFE sheet. We performed debridement and switched to VAC therapy 2 weeks after starting continuous drainage of the abscess in the chest wall. The space around the PTFE sheet gradually decreased, and formation of wound granulation progressed. We performed wound closure 6 weeks after starting VAC therapy, and the patient was discharged 67 days after hospitalization.

CONCLUSIONS

We experienced a case of chest wall reconstruction infection after surgery for non-small cell lung cancer that was successfully treated by VAC therapy without removal of the prosthesis. Although removal of an infectious artificial prosthesis can be avoided by application of VAC therapy, perioperative management to prevent surgical site infection is considered essential.

Epidemiology and Clinical Patterns of Lung Abscesses in ICU: A French Multicenter Retrospective Study

BACKGROUND

Data are scarce regarding epidemiology and management of critically ill patients with lung abscesses.

RESEARCH QUESTION

What are the clinical and microbiological characteristics of critically ill patients with lung abscesses, how are they managed in the ICU, and what are the risk factors of in-ICU mortality?

STUDY DESIGN AND METHODS

This was a retrospective observational multicenter study, based on International Classification of Diseases, 10th Revision, codes, between 2015 and 2022 in France. In-ICU mortality-associated factors were determined by multivariate logistic regression.

RESULTS

We analyzed 171 ICU patients with pulmonary abscesses. Seventy-eight percent were male, with a mean age of 56.5 ± 16.4 years; 20.4% misused alcohol, 25.2% had a chronic lung disease (14% COPD), and 20.5% had a history of cancer. Overall, 40.9% were immunocompromised and 38% qualified for nosocomial infection. Presenting symptoms included fatigue or weight loss in 62%, fever (50.3%), and dyspnea (47.4%). Hemoptysis was reported in 21.7%. A polymicrobial infection was present in 35.6%. The most frequent pathogens were Enterobacteriaceae in 31%, Staphylococcus aureus in 22%, and Pseudomonas aeruginosa in 19.3%. Fungal infections were found in 10.5%. Several clusters of clinicoradiologic patterns were associated with specific microbiological documentation and could guide empiric antibiotic regimen. Percutaneous abscess drainage was performed in 11.7%; surgery was performed in 12.7%, and 12% required bronchial artery embolization for hemoptysis. In-ICU mortality was 21.5%, and age (OR: 1.05 [1.02-1.91], P = .007], renal replacement therapy during ICU stay (OR, 3.56 [1.24-10.57], P = .019), and fungal infection (OR, 9.12 [2.69-34.5], P = .0006) were independent predictors of mortality after multivariate logistic regression, and drainage or surgery were not.

INTERPRETATION

Pulmonary abscesses in the ICU are a rare but severe disease often resulting from a polymicrobial infection, with a high proportion of Enterobacteriaceae, S aureus, and P aeruginosa. Percutaneous drainage, surgery, or arterial embolization was required in more than one-third of cases. Further prospective studies focusing on first-line antimicrobial therapy and source control procedure are warranted to improve and standardize patient management.

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.

Lung Abscess Caused by Tannerella forsythia Infection: A Case Report

Background

Tannerella forsythia is a gram-negative anaerobic bacterium commonly found in the oral cavity. It is among the common pathogenic bacteria associated with gingivitis, chronic periodontitis, and aggressive periodontitis. However, there is currently no literature discussing lung abscesses primarily caused by T. forsythia infection.

Presentation

This article presents the case of a 55-year-old male with a massive lung abscess. The patient underwent ultrasound-guided percutaneous drainage, and the sample was sent for pathogen metagenomic next-generation sequencing (mNGS) testing. The test indicated that the lung abscess was primarily caused by T. forsythia infection. A literature review was conducted to understand the characteristics of this pathogen as well as its clinical features and suitable treatment approaches.

Conclusion

Currently, there is no literature specifically mentioning T. forsythia as a primary pathogen causing lung abscesses. This anaerobic bacterium is commonly found in the oral cavity and is difficult to cultivate using routine culture methods. mNGS emerges as a value diagnostic method for identifying this pathogen. Treatment recommendations include drainage and antibiotic selection encompassing common periodontal pathogens such as red complex bacteria and Actinomyces.

The Drug-Specific Propensity Regarding the Acquisition of Fluoroquinolone Resistance in Escherichia coli: An in vitro Challenge and DNA Mutation Analysis

Objective

Many fluoroquinolones, such as ciprofloxacin, are used clinically. We investigated the relationship between resistance acquisition and exposure duration in each drug through the exposure of fluoroquinolone to Escherichia coli clinical isolates in vitro.

Methods

Eleven E. coli clinical isolates were exposed to each fluoroquinolone, ie, ciprofloxacin, levofloxacin, sitafloxacin, garenoxacin, and lascufloxacin, with the concentration of the mutant selection window for 5 days; these procedures were repeated 5-times. In addition, the DNA sequence in the quinolone-resistance determining region (QRDR) and the expression level in the drug efflux pump acrA were analyzed to determine the resistance mechanism.

Results

Although resistant strains were not detected after 5 to 10 days of exposure to fluoroquinolone, after 25 days of exposure to ciprofloxacin and levofloxacin, 100% and 45% of isolates acquired resistance, respectively. Due to 25 days of exposure to sitafloxacin, garenoxacin, and lascufloxacin, MIC measurement was elevated 2- to 4096-fold for those of the parental strain, and the cross-resistance rate to levofloxacin was 72%, 54%, and 27%, respectively. In strains with high fluoroquinolone resistance, acrA overexpression was observed in addition to QRDR mutation.

Conclusion

In our findings, fluoroquinolone resistance was not observed in the E. coli strain after 5- to 10-days of exposure. However, resistance acquisition was detected frequently after 15- to 25-days of exposure. Among fluoroquinolones, lascufloxacn had the least impact on the resistance acquisition in E. coli.

Lung abscess: Clinical characteristics of 222 Danish patients diagnosed from 2016 to 2021

INTRODUCTION

Lung abscess (LA) is a serious respiratory infection often followed by several weeks of antibiotic treatment. This study described the clinical presentation of LA, treatment duration and mortality in a contemporary Danish population.

METHODS

In a retrospective multicenter cohort study at four Danish hospitals, patients diagnosed with LA were identified using the International Classification of Diseases and Related Health Problems 10th revision (ICD-10) between 2016 and 2021. A predefined data collection tool was used to extract data on demographics, symptoms, clinical findings and treatment.

RESULTS

Of 302 patients, 222 with LA were included after review of patient records (76%). Mean age was 65 years (54-74), 62.9% was male and 74.9% were ever-smokers. Chronic obstructive pulmonary disease (COPD) (35.1%), use of sedatives (29.3%) and alcohol abuse (21.8%) were common risk factors. Dental status was reported in 51.4%, whereof 41.6% had poor dental status. Patients presented with cough (78.8%), malaise (61.3%) and fever (56.8%) Patients were hospitalized for a median of 14 days (interquartile ranges, IQR 7-21) and median duration of antibiotic treatment was 38 days (IQR 30-51). All-cause mortality after 1, 3 and 12 months was 2.7%, 7.7% and 15.8%, respectively.

CONCLUSION

Risk factors for LA include COPD and use of sedatives, alcohol abuse, and poor dental status. Despite long-term antibiotic treatment, long-term mortality is markedly high.

Evaluation of the Diagnostic Performance of mNGS in Detecting Intra-Abdominal Infections of the Emergency Department Patients

Purpose

Intra-abdominal infections (IAI) are gradually becoming common in the emergency department, though the incidence is low and the prognosis is fair, as the symptoms are similar to other intra-abdominal diseases, rapid and accurate diagnosis of the causative agents is essential for clinical management. This study aimed to evaluate the diagnostic performance of metagenomic next-generation sequencing (mNGS) in detecting IAI in the emergency department.

Patients and Methods

This was a retrospective, single-centered study including patients admitted to the emergency department from January 1st, 2021 to August 31st, 2022 with diagnosis of IAI. The comparison between mNGS and microbial culture using paracentesis fluid samples was performed to evaluate the diagnostic performance of mNGS for IAI. Meanwhile, paracentesis fluid and peripheral blood mNGS were compared to explore the sample specificity. Further, the microbial community structure of the patients with pyogenic liver abscesses (PLA) was analyzed.

Results

Thirty-four IAI patients including 23 with pyogenic liver abscesses (PLA), 3 with parapancreatic abscesses, and 8 with other IAI were included in this study. Compared with the conventional microbial culture of paracentesis fluid, mNGS using paracentesis fluid detected more positive cases of IAI (93.75% vs 81.25%), and identified more species of pathogens, especially in obligate anaerobes and viral pathogens. Peripheral blood mNGS presented a relatively high consistency with the paracentesis fluid mNGS (91% mutual positive). The microbial community structure of PLA patients with diabetes is less diverse than that of those without diabetes. Patients with diabetes are at high risk of PLA caused by Klebsiella pneumonia.

Conclusion

mNGS has advantages in detecting IAI in the emergency department, and peripheral blood mNGS can be a non-invasive choice for early diagnosis.

Invasive Pneumococcal Disease and COVID-19 Coinfection: A Series of Cases Admitted to an Intensive Care Unit

Pneumococcal infection is still a frequent disease. It can be classified as invasive when pneumococcus is isolated in a generally sterile fluid. Pneumonia is the most common infectious source of adult invasive pneumococcal disease (IPD), and several risk factors for IPD are well known. This case report presents three clinical cases of different manifestations of IPD. The two most severe cases had coinfection by SARS-CoV-2 at hospital admission.

The Clinical Features and Management of Empyema Caused by Streptococcus constellatus

Background

Streptococcus constellatus, a commensal, plays an important role in purulent infections. It has been reported as aggressive pathogen causing pleural empyema. But the role of S. constellatus in empyema has not been taken seriously. There are no studies about clinical characteristics of empyema caused by S. constellatus domestically and abroad. This study aimed to explore the clinical features and management of empyema caused by S. constellatus.

Methods

A retrospective review of 9 patients diagnosed with empyema caused by S. constellatus in a hospital between January 2010 and August 2021 was performed.

Results

S. constellatus empyema were mostly seen in old males (66.7%) with comorbid diseases. The high-risk factors include diabetes mellitus, oral infection, and oral surgery. All were unilateral encapsulated empyema (right-side, 55.6%), diagnosed with pneumonia (bilateral pneumonia, 88.9%; ipsilateral lung abscess, 44.4%). 33.3% of patients had S. constellatus and anaerobes co-isolated. S. constellatus were sensitive to penicillin G, linezolid, levofloxacin, vancomycin, ceftriaxone, and chloramphenicol, resistant to erythromycin, tetracycline, and clindamycin. 33.3% of the patients needed ventilator support. The primary treatment to S. constellatus empyema was timely pus drainage, intravenous antibiotics, and enough nutrition support, intrapleural fibrinolytics and surgery (VAST recommended first) in necessity.

Conclusion

S. constellatus may cause pneumonia and lung abscess first and then spread to cause empyema mainly in old males with comorbid diseases. S. constellatus often co-isolated with anaerobes in empyema. Antibiotics should cover simultaneously both S. constellatus and anaerobes.

The Mass-Querade: Lung Abscess Mimicking Primary Lung Cancer

A 68-year-old male with a known history of von Hippel-Lindau disease with brain hemangioblastoma status post radiation therapy and recurrent hemangioblastoma in the spine and multiple spinal surgeries presented initially to the emergency department due to hemoptysis and worsening shortness of breath. A CT chest demonstrated a left lung mass and left pleural effusion, which was initially suspected to be lung malignancy given his symptoms and history. However, it was determined to be a lung abscess following workup and consultations. This case highlights the similarities in the presentation of both pathologies and the critical features in lung abscesses.

Ultrasonography in the diagnosis of lung abscess

This case demonstrates the usefulness of lung ultrasound in the diagnosis of lung abscess, which showed a rounded hypoechoic image within a left basal consolidation in a critically ill patient requiring mechanical ventilation support.

Pulmonary actinomycosis and polymicrobial empyema in a patient with ABPA and bronchocoele

We present a 43-year-old woman, with a history of allergic bronchopulmonary aspergillosis and a chronic bronchocoele, who was admitted to hospital with an infection of the bronchocoele, progressing to a pulmonary abscess and polymicrobial empyema, following dental extraction and regular Lactobacillus probiotic ingestion. Interval chest imaging following this procedure demonstrated worsening right upper lobe opacities and a right-sided pleural effusion. Bronchoscopies identified copious mucoid secretions and an infected bronchocoele with a right upper lobe airways impaction. Oral cavity organisms including Actinomyces odontolyticus were cultured on bronchial washings. Streptococcus mitis and Lactobacillus rhamnosus were cultured in pleural fluid. Treatment with endoscopic mucoid secretion suctioning; intercostal catheter insertion and therapeutic drainage; and antibiotic, glucocorticoid and anti-IgE therapy resulted in clinical and radiological improvement. Our case illustrates the potential pulmonary complications from oral cavity organisms following tooth extraction and probiotic use in patients with chronic lung disease associated with mucoid lesions and airways obstruction.

Diagnostic performance of the metagenomic next-generation sequencing in lung biopsy tissues in patients suspected of having a local pulmonary infection

Purpose

This study aims to evaluate the diagnostic application and performance of the metagenomic next-generation sequencing (mNGS) in patients suspected of local pulmonary infection by comparing it to the traditional pathogen detection methods in lung tissue specimens obtained by a computerized tomography-guided biopsy (CT-guided biopsy).

Methods

We retrospectively reviewed patients, admitted to the First Affiliated Hospital of Wenzhou Medical University, China from May 2018 to December 2020, who were suspected of local pulmonary infection. All cases received a CT-guided lung biopsy, tissue samples were sent both for conventional examinations (CE) and mNGS tests. The sensitivity and specificity of the two diagnostic approaches were compared.

Results

106 patients enrolled, 76 patients were diagnosed with a pulmonary infection. Among 49 patients with identified pathogens, CE confirmed pathogenic infections in 32 cases. Mycobacterium spp. and fungi accounted for 37.5% (12/32) and 28.1% (9/32), respectively, with bacteria 34.4% (11/32). The mNGS examination detected extra pathogenic microorganisms in 22 patients that were consistent with the patients' clinical and radiographic pictures. The sensitivity of mNGS was 53.9% vs. 42.1% for the CE, while the specificity was 56.7% versus 96.7%. For detection rate, mNGS was significantly superior to CE in bacterial (96.3% vs. 40.7%, p < 0.05), and mixed infections (100% vs. 50%, p < 0.05), but inferior to CE in fungal (60% vs. 90%, p > 0.05) and Mycobacterium spp. infections (66.7% vs. 100%, p > 0.05) with no significant difference. Among 31 cases diagnosed with lung abscess, the diagnostic performance of the detection rate was 67.7% (21/31) in favour of mNGS compared to 29.0% (9/31) for CE (p < 0.05). Most polymicrobial infections were induced by anaerobic species that coexisted with Streptococcus constellatus. And Klebsiella pneumoniae was the most common isolated monomicrobial infection.

Conclusions

The most commonly detected causative pathogens for local pulmonary infections were bacteria, Mycobacterium spp. and fungi. Compared with the CE, the advantages of mNGS in the pathogens detection lie in the discovery of bacterial and mixed infections, as well as in the detection of lung abscess. Conversely, mNGS is not good enough to be recommendable for the detection of Mycobacterium spp. and fungi.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01912-4.

Genetic Homology between Bacteria Isolated from Pulmonary Abscesses or Pyothorax and Bacteria from the Oral Cavity

Pulmonary abscesses and pyothorax are bacterial infections believed to be caused primarily by oral microbes. However, past reports addressing such infections have not provided genetic evidence and lack accuracy, as they used samples that had passed through the oral cavity. The aim of this study was to determine whether genetically identical bacterial strains exist in both the oral microbiota and pus specimens that were obtained percutaneously from pulmonary abscesses and pyothorax, without oral contamination. First, bacteria isolated from pus were identified by 16S rRNA gene sequencing. It was then determined by quantitative PCR using bacterial-species-specific primers that DNA extracted from paired patient oral swab sample suspensions contained the same species. This demonstrated sufficient levels of bacterial DNA of the targeted species to use for further analysis in 8 of 31 strains. Therefore, the whole-genome sequences of these eight strains were subsequently determined and compared against an open database of the same species. Five strain-specific primers were synthesized for each of the eight strains. DNA extracted from the paired oral swab sample suspensions of the corresponding patients was PCR amplified using five strain-specific primers. The results provided strong evidence that certain pus-derived bacterial strains were of oral origin. Furthermore, this two-step identification process provides a novel method that will contribute to the study of certain pathogens of the microbiota.

IMPORTANCE We present direct genetic evidence that some of the bacteria in pulmonary abscesses and pyothorax are derived from the oral flora. This is the first report describing the presence of genetically homologous strains both in pus from pulmonary abscesses and pyothorax and in swab samples from the mouth. We developed a new method incorporating quantitative PCR and next-generation sequencing and successfully prevented contamination of pus specimens with oral bacteria by percutaneous sample collection. The new genetic method would be useful for enabling investigations on other miscellaneous flora; for example, detection of pathogens from the intestinal flora at the strain level.

Prospective Evaluation of a Rapid Clinical Metagenomics Test for Bacterial Pneumonia

Background

The diagnosis of bacterial pathogens in lower respiratory tract infections (LRI) using conventional culture methods remains challenging and time-consuming.

Objectives

To evaluate the clinical performance of a rapid nanopore-sequencing based metagenomics test for diagnosis of bacterial pathogens in common LRIs through a large-scale prospective study.

Methods

We enrolled 292 hospitalized patients suspected to have LRIs between November 2018 and June 2019 in a single-center, prospective cohort study. Rapid clinical metagenomics test was performed on-site, and the results were compared with those of routine microbiology tests.

Results

171 bronchoalveolar lavage fluid (BAL) and 121 sputum samples were collected from patients with six kinds of LRIs. The turnaround time (from sample registration to result) for the rapid metagenomics test was 6.4 ± 1.4 hours, compared to 94.8 ± 34.9 hours for routine culture. Compared with culture and real-time PCR validation tests, rapid metagenomics achieved 96.6% sensitivity and 88.0% specificity and identified pathogens in 63 out of 161 (39.1%) culture-negative samples. Correlation between enriched anaerobes and lung abscess was observed by Gene Set Enrichment Analysis. Moreover, 38 anaerobic species failed in culture was identified by metagenomics sequencing. The hypothetical impact of metagenomics test proposed antibiotic de-escalation in 34 patients compared to 1 using routine culture.

Conclusions

Rapid clinical metagenomics test improved pathogen detection yield in the diagnosis of LRI. Empirical antimicrobial therapy could be de-escalated if rapid metagenomics test results were hypothetically applied to clinical management.

Identification of Dominant Bacteria Isolated From Periodontal Abscesses

Aim:

Various methods investigating the bacterial content causing periodontal abscesses have been applied in studies conducted until today. However, these studies have focused on periodontopathogens. Our study was carried out to research whether different pathogens other than the known periodontopathogens are present in periodontal abscess formation. Therefore, dominant bacterial samples obtained from the periodontal abscess content using the culture-dependent method were identified by 16S rDNA sequencing.

Materials and Methods:

Samples were obtained using a syringe or a periopaper from periodontal abscesses of 20 volunteers who met the research criteria. The three different bacterial colonies that were observed most intensely in each sample were selected and purified, and the isolates obtained were kept until the next characterization. Genomic DNA was isolated from each isolate; 16S rRNA genes were amplified by polymerase chain reaction and identified using DNA sequencing analyses.

Results:

As a result of culture-dependent methods, bacterial species belonging to Streptococcus, Staphylococcus, Neisseria, Actinomyces, Morococcus, Moraxella, and Enterococcus genera were isolated from a total of 60 bacterial isolates, three of which were the most densely growing colonies from each periodontal abscess sample.

Conclusion:

In our study, most of the bacterial species detected were identified for the first time in the bacterial content of periodontal abscesses. In some previously done studies, most of these bacteria species were shown to cause abscesses in different parts of the body. It was concluded that further studies are needed to determine the number and proportion of these bacteria species in total bacterial content to evaluate whether they cause periodontal abscesses.

Primary lung abscess due to multidrug-resistant Klebsiella pneumoniae

Primary lung abscess as a complication of necrotising community-acquired pneumonia due to multidrug-resistant (MDR) Klebsiella pneumoniae is rare. A 63-year-old man with a medical history of type 2 diabetes mellitus and chronic kidney disease was diagnosed with lung abscess due to MDR Klebsiella pneumoniae, a rare organism as a causative agent for community-acquired pneumonia. This unusual case revealed therapeutic challenges faced owing to factors such as drug-resistant pathogen, longer duration of antibiotics required for lung abscess and the chronic kidney status of the patient limiting the dosage of antibiotics. The clinical nuggets discussed in this case might pave the way in the future for management guidelines to be formulated in optimising the selection and duration of therapy for lung abscesses with MDR aetiology and in early recognition of this rare but dreaded entity.

Percutaneous transthoracic catheter drainage for lung abscess: a systematic review and meta-analysis

OBJECTIVES

To evaluate the outcomes of patients receiving image-guided percutaneous catheter drainage (PCD) for lung abscesses in terms of treatment success, major complications, and mortality as well as the predictors of those outcomes.

METHODS

Embase and OVID-MEDLINE databases were searched to identify studies on lung abscesses treated with PCD that had extractable outcomes. The outcomes were pooled using a random-intercept logistic regression model. Multivariate Firth's bias-reduced penalised-likelihood logistic regression analyses were performed to identify predictors of treatment success and complications. Methodological quality was assessed by summing scores of binary responses to items regarding selection, ascertainment of exposure and outcome, causality of follow-up duration, and reporting.

RESULTS

From 26 studies with acceptable methodological quality (median score, 4; range, 3-5), 194 patients were included. The pooled rates of treatment success and major complications were 86.5% (95% confidence interval [CI], 78.5-91.8%; I² = 23%) and 8.1% (95% CI, 4.1-15.3%; I² = 26%), respectively. Four patients eventually died from uncontrolled lung abscesses (pooled rate, 1.5%; 95% CI, 0.2-11.1%; I² = 36%). Malignancy-related abscess (odds ratio [OR], 0.129; 95% CI, 0.024-0.724; p = .022) and the occurrence of a major complication (OR, 0.065; 95% CI, 0.02-0.193; p < .001) were significant predictors of treatment failure. Traversing normal lung parenchyma was the only significant risk factor for major complications (OR, 27.69; 95% CI, 7.196-123.603; p < .001).

CONCLUSION

PCD under imaging guidance was effective for lung abscess treatment, with a low complication rate. Traversal of normal lung parenchyma was the sole risk factor for complications, and malignancy-related abscesses and the occurrence of major complications were predictors of treatment failure.

KEY POINTS

• The pooled treatment success rate of PCD for lung abscess was reasonably high (86.5%); malignancy-related abscesses and the occurrence of a major complication were predictors of treatment failure. • The pooled rate of percutaneous transthoracic catheter drainage-related major complications was 8.1% and traversing normal lung parenchyma by the catheter was the only risk factor. • The pooled mortality rate from uncontrolled lung abscesses with percutaneous transthoracic catheter drainage was low.

[Management of Adult Community-Acquired Pneumonia and Prevention - Update 2021 - Guideline of the German Respiratory Society (DGP), the Paul-Ehrlich-Society for Chemotherapy (PEG), the German Society for Infectious Diseases (DGI), the German Society of Medical Intensive Care and Emergency Medicine (DGIIN), the German Viological Society (DGV), the Competence Network CAPNETZ, the German College of General Practitioneers and Family Physicians (DEGAM), the German Society for Geriatric Medicine (DGG), the German Palliative Society (DGP), the Austrian Society of Pneumology Society (ÖGP), the Austrian Society for Infectious and Tropical Diseases (ÖGIT), the Swiss Respiratory Society (SGP) and the Swiss Society for Infectious Diseases Society (SSI)]

The present guideline provides a new and updated concept of the management of adult patients with community-acquired pneumonia. It replaces the previous guideline dating from 2016.The guideline was worked out and agreed on following the standards of methodology of a S3-guideline. This includes a systematic literature search and grading, a structured discussion of recommendations supported by the literature as well as the declaration and assessment of potential conflicts of interests.The guideline has a focus on specific clinical circumstances, an update on severity assessment, and includes recommendations for an individualized selection of antimicrobial treatment.The recommendations aim at the same time at a structured assessment of risk for adverse outcome as well as an early determination of treatment goals in order to reduce mortality in patients with curative treatment goal and to provide palliation for patients with treatment restrictions.

Pyogenic lung abscess in an infectious disease unit: a 20-year retrospective study

Background:

Pyogenic lung abscesses are rare and poorly described infections. This study aimed to describe their prognostic factors.

Methods:

We retrospectively included all patients hospitalized between 1 January 1998 and 1 June 2018, with an International Classification of Diseases, version 10 (IDC-10) diagnosis of pyogenic lung abscess, from the Diamm based medical records (Micro6, Nancy, France). Parasitic, fungal, or mycobacterial lung abscesses were excluded.

Results:

A total of 64 patients were included. Abscesses were associated with immunosuppression in 28 patients, including HIV infection and immunosuppressive therapy for eight and 12 patients, respectively. Bacterial identification was obtained for 36 patients. Nine patients (14%) developed lung abscesses after hematogenous dissemination. They differed from bronchogenic abscesses by their younger age (p = 0.03), the absence of smoking or emphysema (p = 0.05), Staphylococcus aureus (p = 0.001) or Streptococcus spp. (p = 0.05) isolation, and the smaller size of their abscess (p = 0.02). Overall, evolution was marked by radiological sequelae (46.9%), relapse (12.5%), and death (4.8%). Radiological sequelae occurred more frequently during the course of bronchogenic abscesses (p = 0.02), particularly when they spontaneously discharged (p = 0.04). Relapses were more frequent in patients with emphysema (p = 0.04) and when Haemophilus influenzae was isolated (p = 0.04). In multivariate analysis, poor outcomes, including death, sequelae, and relapse occurred more frequently in patients who had bronchogenic abscess (p = 0.02), and in those who received antibiotics during less than 6 weeks (p = 0.05).

Conclusion:

A duration of antibiotic treatment of less than 6 weeks and bronchogenic presentation were globally associated with poor outcome of pyogenic lung abscesses. These data should be considered when proposing guidelines for the care of pyogenic lung abscesses.

The reviews of this paper are available via the supplemental material section.

Pulmonary Aggregatibacter actinomycetemcomitans infection masquerades as malignancy in a patient with periodontitis

A 49-year-old man with a 37.5 pack-year smoking history presented with a suspected neoplasm of the right lung following the discovery of a metabolically active mass on positron emission tomography-CT imaging. The patient, who demonstrated poor oral hygiene, had a history of irregular problem-oriented dental visitation. Having excluded malignancy through histologic investigations, Aggregatibacter actinomycetemcomitans-a well-established periodontal pathogen-was subsequently cultured from his pulmonary aspirate. The patient was therefore managed with systemic antimicrobials and adjunctive dental extractions to eliminate the likely source of infection, whereafter the mass resolved without complication. This case corroborates previous reports of extraoral isolation of A. actinomycetemcomitans, which may mimic cancer clinically and radiographically. While a definitive causative link between untreated periodontitis and systemic infection remains to be elucidated, such cases present a compelling argument in favour of promoting oral health to prevent systemic disease.

[Management of Lung Abscess - Diagnostics and Treatment]

Lung abscess is a localized infectious pus-filled cavity of the lung tissue by viral, bacterial, mycotic or parasitic pathogens. Currently, there are different classifications, which are based primarily on the genesis and duration of symptoms. Important steps for diagnosis are in addition to clinical examination, laboratory and chest X-ray especially bronchoscopy with microbiological examinations and computed tomography. Treatment of lung abscesses continues to be a domain of conservative antibiotic therapy. The vast majority of cases can be cured with this. Interventional procedures such as transthoracic or endobronchial abscess drainage with subsequent irrigation can effectively support the healing process. Thoracic surgery is particularly important in cases of failure of conservative and interventional therapy as well as secondary abscesses on the basis of a lung carcinoma. Mostly anatomical resections are required. Alternatively, VAC therapy (vacuum-assisted closure therapy) may be considered in seriously ill, old, immunosuppressed, and multimorbid patients with complicated abscesses (e.g. perforation in the pleural cavity and sero-pneumothorax).

Cytotoxic property of Streptococcus mitis strain producing two different types of cholesterol-dependent cytolysins

Streptococcus mitis strain Nm-65 secretes an atypical 5-domain-type cholesterol-dependent cytolysin (CDC) called S. mitis-derived human platelet aggregation factor (Sm-hPAF) originally described as a platelet aggregation factor. Sm-hPAF belongs to Group III CDC that recognize both membrane cholesterol and human CD59 as the receptors, and shows preferential activity towards human cells. Draft genome analyses have shown that the Nm-65 strain also harbors a gene encoding another CDC called mitilysin (MLY). This CDC belongs to Group I CDC that recognizes only membrane cholesterol as a receptor, and it is a homolog of the pneumococcal CDC, pneumolysin. The genes encoding each CDC are located about 20 kb apart on the Nm-65 genome. Analysis of the genomic locus of these CDC-encoding genes in silico showed that the gene encoding Sm-hPAF and the region including the gene encoding MLY were both inserted into a specific locus of the S. mitis genome. The results obtained using deletion mutants of the gene(s) encoding CDC in Nm-65 indicated that each CDC contributes to both hemolysis and cytotoxicity, and that MLY is the major hemolysin/cytolysin in Nm-65. The present study aimed to determine the potential pathogenicity of an S. mitis strain that produces two CDC with different receptor recognition properties and secretion modes.

Fluid-filled Cystic Lesions of the Lungs

A pulmonary cyst usually refers to an air-filled space with a smooth, thin wall. Fluid-filled cystic lesions of the lungs include a range of etiologies such as true cysts, congenital malformations, infections, and benign and malignant neoplasms. With relatively little solid component, these lesions often have similar imaging appearances to one another. This article focuses on key imaging features and clinical characteristics that can be used to narrow the differential diagnosis.

Comparison between Patients with Chest Infection due to Klebsiella spp. and Streptococcus pneumoniae

Objective In Japan, the aging demographic structure is becoming pronounced, and the full-blown graying of society appears not far off, which indicates an increasing population that will require healthcare contact. Klebsiella spp. are major pathogens in healthcare-associated infections, and their importance is increasing. The aim of this study was to clarify the characteristics of Klebsiella spp. chest infections by evaluating the differences in the characteristics of chest infections caused by Klebsiella spp. and pneumoniae. Methods We conducted a retrospective study of consecutive patients hospitalized with pneumonia, lung abscess/necrotizing pneumonia, and empyema due to Klebsiella spp. and S. pneumoniae for 15 years at our institution in Saitama, Japan. Patients Patients with chest infections due to Klebsiella spp. (K group, n=76) and S. pneumoniae (S group, n=446) were included. Results The K group more frequently was male, older, coinfected by Pseudomonas aeruginosa, and had diabetes mellitus, a history of upper digestive system surgery, alcohol drinking habit, a smoking habit, and an impaired premorbid performance status than the S group. The percentages of lung abscesses or necrotizing pneumonia (31.6% vs. 0.9%) and empyema without pulmonary parenchymal shadow (3.9% vs. 0.7%) were higher in the K group than those in the S group. Severity on admission and mortality did not differ between the groups; however, patients in the K group required a longer duration of antibiotics administration and hospital stay than those in the S group. Conclusion Klebsiella spp. chest infections have some marked characteristics when compared with pneumococcal infections, and our results serve to differentiate Klebsiella spp. infection from pneumococcal infection.

Effects of Anaerobic Culturing on Pathogenicity and Virulence-Related Gene Expression in Pneumococcal Pneumonia

BACKGROUND

The pathogenicity of Streptococcus pneumoniae under anaerobic conditions remains largely unknown. We examined the pathogenicity of S. pneumoniae cultured under anaerobic conditions in a murine model of pneumococcal pneumonia.

METHODS

Mice were infected with S. pneumoniae grown under anaerobic or aerobic conditions. The pathogenic effects in vivo in the lower airway tract were then compared. The effect of anaerobic culture on lytA/ply transcript levels in vitro and in vivo were analyzed by quantitative real-time polymerase chain reaction.

RESULTS

Mice inoculated with anaerobically cultured S. pneumoniae exhibited significantly lower survival rates and higher bacterial loads in the lungs and blood as compared to those infected with aerobically cultured S. pneumoniae. Aerobically cultured S. pneumoniae in the early log phase of growth was also able to induce severe pneumonia at levels equivalent to those of anaerobic S. pneumoniae. However, ply/gyrB transcript levels were significantly increased in the lungs of mice infected with anaerobically grown S. pneumoniae. In vitro, S. pneumoniae grown under anaerobic culture conditions demonstrated greater proliferation than S. pneumoniae grown under aerobic culture conditions, and bacterial concentrations were maintained for 24 hours without detectable upregulation of lytA messenger RNA.

CONCLUSIONS

S. pneumoniae grown under anaerobic conditions had the potential to induce severe invasive bacteremic pneumococcal pneumonia in a manner different from that of S. pneumoniae grown under aerobic conditions.

Ceftriaxone versus ampicillin/sulbactam for the treatment of aspiration-associated pneumonia in adults

Aim: To compare hospital mortality in patients with aspiration-associated pneumonia treated with ceftriaxone (CTRX) and in those treated with ampicillin/sulbactam (ABPC/SBT). Methods: From a Japanese multicentre observational study cohort of patients with pneumonia, those diagnosed with pneumonia and having at least one aspiration-related risk factor were selected. Propensity score-matching analysis was used to balance baseline characteristics of the participants and compare hospital mortality of patients treated with CTRX and those treated with ABPC/SBT. Results: Hospital mortality did not significantly differ between patients treated with CTRX and those treated with ABPC/SBT (6.6 vs 10.7%, risk difference -4.0, 95% CI [-9.4, 1.3]; p = 0.143). Conclusion: Further studies are needed to compare CTRX and ABPC/SBT treatments in patients with aspiration-associated pneumonia.

A case report of disseminated nocardiosis with ocular involvement in a myasthenia gravis patient and literature review

Background

Nocardiosis is a rare and life-threatening opportunistic infection in immunocompromised patients. Myasthenia gravis (MG) patients are potentially at risk of nocardia infection because of the use of immunosuppressive agents. To date, only 7 patients with MG have been reported to have nocardiosis. Disseminated nocardiosis with ocular involvement has not been reported in MG patients.

Case presentation

A 66-year-old man with MG who was receiving treatment with methylprednisolone and azathioprine was found to have a respiratory infection. He also had heterogeneous symptoms with skin, brain and ocular manifestations. Nocardia bacteria verified by the culture of puncture fluid, and a diagnosis of disseminated nocardiosis was made. Except for left eye blindness, the patient completely recovered from the disease with combination antibiotic therapy. To further understand nocardiosis in patients with MG, we reviewed the previous relevant literature. According to the literature, this is the first report of disseminated nocardiosis with ocular involvement in an MG patient.

Conclusions

MG patients with immunosuppressant treatments are potentially at risk of a rare nocardia infection, and a favourable prognosis can be achieved through early diagnosis and appropriate antibiotic therapy.

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.

A community-acquired lung abscess attributable to odontogenic flora

A lung abscess is an infectious pulmonary disease characterized by pus-filled cavity formation and often an air-fluid level. In this article, we described an indolent community-acquired lung abscess suspected as a tumor previously. A 56-year-old male presented with cough and expectoration for 2 months and hemoptysis for 2 weeks. His physical examinations, whole blood count and C-reactive protein level were normal. The chest computed tomography (CT) scan showed a 40×38×39 mm high-density mass in the right upper pulmonary lobe, with irregular borders. The pathology of a CT-guided percutaneous needle aspiration biopsy showed numerous inflammatory cells and bacteria infiltration without tumor lesions. Bacteriological detection of lung tissue revealed the cause was odontogenic flora. A next-generation sequencing demonstrated the etiologic correlation between lung abscess and periodontitis. After a 2-month pathogen-directed oral antibiotics therapy combined with chlorhexidine gargle oral care, this patient showed a remarkable improvement. Periodontitis can be a cause of a lung abscess, which would be taken into account in the treatment regimes preventing infectious recurrence.

[Lung abscess: Diagnosis and management]

Lung abscesses are necrotic cavitary lesions of the lung parenchyma. They are usually caused by anaerobic bacteria or mixed flora and typically occur after aspiration. Primary lung abscesses occur in previously healthy patients with no underlying medical disorders and are usually solitary. Secondary lung abscesses occur in patients with underlying or predisposing conditions and may be multiple. The initial diagnosis is usually made by chest radiography showing a lung cavity with an air-fluid level. Typically, the cavity wall is thick and irregular, and a surrounding pulmonary infiltrate is often present. The differential diagnosis of pulmonary cavitation is wide, including different types of possible infections, neoplasia and malformations of the bronchial tree. Management is usually based on prolonged antibiotic treatment. Failure of conservative management, manifested by the persistence of sepsis and/or other abscess complications, may necessitate drainage with invasive techniques (percutaneous, endoscopic or surgical) or open surgical removal of the lung lesion in patients with good performance status and sufficient respiratory reserve.

Unusual case of a giant lung abscess initially misdiagnosed and treated as an empyema

We report the case of a 66-year-old man with dental infection who presented to our emergency department complaining of a 3-month medical history of chest pain and productive cough, in association with malaise, fever, weight loss and anaemia. His chest radiograph showed a nearly total opacification of the right hemithorax and chest ultrasound findings were suggestive of empyema, subsequently confirmed by a chest CT. The patient started appropriate treatment. A follow-up chest CT performed to rule out bronchopleural fistula revealed a large lung abscess. The patient had the final diagnosis of a giant lung abscess, which was initially thought to be an empyema because of the clinical and radiologic similarities with this entity. The initial misdiagnosis led to prompt percutaneous drainage of the lung abscess in addition to antibiotherapy and respiratory physiotherapy with a good final outcome, which suggests the efficacy of this approach in similar cases.

Logistic regression analysis of clinical and computed tomography features of pulmonary abscesses and risk factors for pulmonary abscess-related empyema

OBJECTIVES

This study was conducted to investigate the risk factors for pulmonary abscess-related empyema by investigating the clinical characteristics and chest computed tomography imaging features of patients with pulmonary abscesses.

METHODS

We retrospectively analyzed the chest computed tomography findings and clinical features of 101 cases of pulmonary abscess, including 25 cases with empyema (the experimental group) and 76 cases with no empyema (the control group). The potential risk factors for pulmonary abscess-related empyema were compared between the groups by using univariate and multivariate logistic regression analyses.

RESULTS

The incidence of pulmonary abscess-related empyema was 24.8% (25/101). Univariate analysis showed that male gender, diabetes, pleuritic symptoms, white blood cells >10×109/L, albumin level <25 g/L, and positive sputum cultures were potential clinical-related risk factors and that an abscess >5 cm in diameter and transpulmonary fissure abscesses were potential computed tomography imaging-related risk factors for pulmonary abscess-related empyema. Multivariate logistic regression analysis showed that transpulmonary fissure abscesses (odds ratio=9.102, p=0.003), diabetes (odds ratio=9.066, p=0.003), an abscess >5 cm in diameter (odds ratio=8.998, p=0.002), and pleuritic symptoms (odds ratio=5.395, p=0.015) were independent risk factors for pulmonary abscess-related empyema.

CONCLUSIONS

Transpulmonary fissure abscesses, diabetes, giant pulmonary abscesses, and pleuritic symptoms increased the risk of empyema among patients with pulmonary abscesses.

The Transbronchial Drainage of a Lung Abscess Using Endobronchial Ultrasonography with a Modified Guide Sheath

Lung abscess is usually treated with long-term antibiotic therapy. Due to the lack of a safe and easy drainage technique, drainage is only applied in refractory cases. We herein describe three cases in which drainage was successfully performed by endobronchial ultrasonography using a modified guide sheath. This procedure may have advantages in the detection of causative pathogens and early infection source control, and may therefore lead to the appropriate selection of antibiotics and reduce the duration of antibiotic therapy.

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.

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.

Clinical, Radiological and Bacteriological Profile of Lung Abscess - An Observational Hospital Based Study

BACKGROUND:

The incidence of lung abscess acquired in the community is unknown, but this is a common clinical problem encountered in developing countries. The incidence of lung abscess was high in the pre-antibiotic era but the advent of susceptible antibiotics it has reduced with an equal fall in mortality to 8.7%. With the emerging antibiotic resistance and change in the trends of bacteriological profile causing lung abscess, it is the need of time to reevaluate lung abscess.

AIM:

The study aimed to determine the clinical, radiological and bacteriological profile of lung abscess.

MATERIAL AND METHOD:

The study was a non-randomized prospective observational study conducted in the department of pulmonary medicine for 18 months. In the study, patients > 15 years of age with clinical features of lung abscess were recruited and were subjected to chest X-ray, routine blood test. Sputum gram stain and culture, as well as antibiotic sensitivity according to the organism, were evaluated. Reports of all investigations along with patient characteristics and risk factors were analysed statistically using SPSS 20.0.

RESULTS:

Forty-six cases of lung abscess were included, and the majority of patients were found to be adults with a mean age of 42.9 years with a male to female ratio of 6.6:1. The most common predisposing factor was an unhygienic oral cavity in 28% of cases with alcohol ingestion being the most important risk factor in 22% of cases. The most common organism found in lung abscess cases was Klebsiella pneumoniae, and they were sensitive to ceftazidime.

CONCLUSION:

Our study shows that Klebsiella pneumoniae should be considered an important pathogen in community-acquired lung abscesses.

Tongue Microbiota and Oral Health Status in Community-Dwelling Elderly Adults

Tongue microbiota are a dominant source of oral microbial populations that are ingested with saliva, and therefore careful attention is required for the maintenance of health of elderly adults, who are susceptible to aspiration of oral contents. This study aimed to investigate the variation in tongue microbiota among community-dwelling elderly adults. Following a dental examination, tongue coating was collected from a 15-mm-diameter circular area at the center of the tongue dorsum of 506 elderly adults aged 70 to 80 years inhabiting the town of Hisayama, Japan. The microbial composition and density were determined by a 16S rRNA gene sequencing approach using a next-generation sequencer and quantitative PCR analysis, respectively. Co-occurrence network analysis identified two cohabiting groups of predominant commensals, one of which was primarily composed of Prevotella histicola, Veillonella atypica, Streptococcus salivarius, and Streptococcus parasanguinis; these organisms have been previously associated with an increased risk of mortality due to pneumonia in the frail elderly. This bacterial group was more predominant in the elderly with fewer teeth, a higher plaque index, and more dental caries experience, whereas the total bacterial density was independent of these traits. A higher density of fungi was also observed in the elderly with these traits, as well as in individuals who wore dentures. These results suggest that elderly adults with poorer oral health swallow a more dysbiotic microbiota formed on the tongue.IMPORTANCE Aspiration of oral contents can lead to pneumonia, which is a major cause of death among elderly adults susceptible to swallowing impairments. Tongue microbiota are a dominant source of oral microbial populations that are ingested with saliva. This large-scale population-based study revealed variations in the tongue microbiota among community-dwelling elderly adults. The total bacterial density was independent of the conditions of teeth surrounding the tongue, whereas the microbiota composition, especially the relative abundances of predominant commensals, showed an association with tooth conditions. Our results demonstrate that the elderly with fewer teeth, poorer dental hygiene, and more dental caries experience constantly ingest more dysbiotic microbiota, which could be harmful for their respiratory health.

In vitro activity of lascufloxacin, a novel fluoroquinolone antibacterial agent, against various clinical isolates of anaerobes and Streptococcus anginosus group

The in vitro activities of lascufloxacin were evaluated by comparison with seven reference compounds using 412 clinical isolates of anaerobes and Streptococcus anginosus group. Lascufloxacin showed potent and broad antibacterial activities greater than those of existing quinolones against the clinical isolates used in this study.

Lung Abscess Remains a Life-Threatening Condition in Pediatrics - A Case Report

Pulmonary abscess or lung abscess is a lung infection which destroys the lung parenchyma leading to cavitations and central necrosis in localised areas formed by thick-walled purulent material. It can be primary or secondary. Lung abscesses can occur at any age, but it seems that paediatric pulmonary abscess morbidity is lower than in adults. We present the case of a one year and 5-month-old male child admitted to our clinic for fever, loss of appetite and an overall altered general status. Laboratory tests revealed elevated inflammatory biomarkers, leukocytosis with neutrophilia, anaemia, thrombocytosis, low serum iron concentration and increased lactate dehydrogenase level. Despite wide-spectrum antibiotic therapy, the patient’s progress remained poor after seven days of treatment and a CT scan established the diagnosis of a large lung abscess. Despite changing the antibiotic therapy, surgical intervention was eventually needed. There was a slow but steady improvment and eventually, the patient was discharged after approximately five weeks.

Lung abscess caused by Streptococcus pneumoniae serotype 6B

Lung abscess has been considered to be a rare complication of pneumococcal infection, and most cases are reported to be Streptococcus pneumoniae serotype 3. A 67-year-old man presented with fever and was diagnosed to have lung abscess caused by S. pneumoniae serotype 6B. The minimal inhibitory concentration (MIC) of penicillin for the isolate was 1 μg/mL. He was treated with high-dose intravenous sulbactam/ampicillin as definitive therapy based on susceptibility testing for S. pneumoniae and recovered successfully without surgical intervention. S. pneumoniae serotype 6B can cause lung abscess.

Rapid screening method for detecting highly pathogenic Streptococcus intermedius strains carrying a mutation in the lacR gene

Streptococcus intermedius is a member of the normal human commensal flora and secretes a human-specific cytolysin intermedilysin (ILY) as a major virulence factor. Expression of ily is repressed by LacR and loss-of-function mutations of LacR are observed in many ILY high-producing strains isolated from deep-seated abscesses, suggesting that high ILY production is necessary for increased virulence. However, because ILY exhibits no β-hemolysis on animal blood agar plates, differentiating ILY high- and low-producing strains using conventional laboratory methods is not possible. Interestingly, S. intermedius also produces glycosidases, including MsgA and NanA, which exhibit N-acetyl-β-d-glucosaminidase and neuraminidase activities, respectively. Moreover, MsgA expression, but not NanA, is negatively regulated by LacR. Here we measured the activities of MsgA, NanA and ILY in strains isolated from clinical specimens and dental plaque to determine the correlation between these glycosidase activities and ILY hemolytic activity. Hemolytic activity showed a strong positive correlation with MsgA and a weak negative correlation with NanA activities. Therefore, we calculated the ratio of MsgA and NanA activity (M/N ratio). This value showed a stronger positive correlation (r = 0.81) with ILY hemolytic activity and many strains with high M/N ratios (>2) were ILY-high producers with loss-of-function mutations in LacR.

Aspiration Pneumonia in Carbon Monoxide Poisoning Patients with Loss of Consciousness: Prevalence, Outcomes, and Risk Factors

BACKGROUND

Aspiration pneumonia is associated with significant morbidity and mortality; however, little is known about aspiration pneumonia in patients with carbon monoxide intoxication, which is the leading cause of poisoning-related death. This study aimed to evaluate the prevalence, clinical impacts, and risk factors for developing aspiration pneumonia in patients with carbon monoxide poisoning with loss of consciousness.

METHODS

A retrospective analysis of a carbon monoxide poisoning registry was performed at our emergency department for the period January 2008 to December 2015. All adult carbon monoxide poisoning patients with loss of consciousness were included.

RESULTS

Aspiration pneumonia developed in 103 (19.2%) of 537 patients. It was associated with increased ventilator use (52.4% vs 3.2%), length of hospital stay (median [interquartile range], 3.6 [2.1-5.1] vs 1.3 [0.6-2.1] days), and in-hospital mortality (5.8% vs 0.0%) (all P < .001). Altered mental status on emergency department arrival, white blood cell count, and increased exposure duration were the independent factors associated with development of aspiration pneumonia; odds ratios were 9.46 (95% confidence interval [CI] 4.92-18.19; P < .001), 1.19 (95% CI 1.13-1.26; P < .001), and 1.12 (95% CI 1.06-1.19; P < .001), respectively. For painful or unresponsive mental status and white blood cell count >12,000/mm³, the odds ratio increased up to 17.75 (95% CI 10.65-29.59; P < .001).

CONCLUSIONS

The prevalence of aspiration pneumonia was 19.2% in carbon monoxide poisoning patients with loss of consciousness and was associated with poor outcomes. Additionally, altered mental status on emergency department arrival, white blood cell count, and increased exposure duration were independently associated with the development of aspiration pneumonia.