Pulmonary thin-section CT findings in acuteMoraxella catarrhalispulmonary infection

Abstract

Objective: Moraxella catarrhalis is an important pathogen in the exacerbation of chronic obstructive pulmonary disease. The aim of this study was to assess the clinical and pulmonary thin-section CT findings in patients with acute M. catarrhalis pulmonary infection. Methods: Thin-section CT scans obtained between January 2004 and March 2009 from 292 patients with acute M. catarrhalis pulmonary infection were retrospectively evaluated. Clinical and pulmonary CT findings in the patients were assessed. Patients with concurrent infection including Streptococcus pneumoniae (n572), Haemophilus influenzae (n561) or multiple pathogens were excluded from this study. Results: The study group comprised 109 patients (66 male, 43 female; age range 28-102 years; mean age 74.9 years). Among the 109 patients, 34 had community-acquired and 75 had nosocomial infections. Underlying diseases included pulmonary emphysema (n574), cardiovascular disease (n544) or malignant disease (n541). Abnormal findings were seen on CT scans in all patients and included ground-glass opacity (n599), bronchial wall thickening (n585) and centrilobular nodules (n579). These abnormalities were predominantly seen in the peripheral lung parenchyma (n599). Pleural effusion was found in eight patients. No patients had mediastinal and/or hilar lymph node enlargement. Conclusions: M. catarrhalis pulmonary infection was observed in elderly patients, often in combination with pulmonary emphysema. CT manifestations of infection were mainly ground-glass opacity, bronchial wall thickening and centilobular nodules. Moraxella catarrhalis is a Gram-negative, aerobic, oxidase-positive diplococcus that was first described in 1896 [1]. The pathogen, also known as Micrococcus catarrhalis, Neisseria catarrhalis and Brahamella catarrhalis, is a clinically important pathogen and is a common cause of respiratory infections, particularly otitis media in children and lower respiratory tract infection in elderly patients [2][3][4][5]. M. catarrhalis is considered to be the third most common and most important cause of bronchopulmonary infections after Streptococcus pneumoniae and Haemophilus influenzae [6,7]. In the Alexander project in Europe and the US between 1992 and 1993, M. catarrhalis was identified in 13.5% of bacterial isolates [8].M. catarrhalis has also gained attention as a nosocomial respiratory pathogen and as a community-acquired pathogen. On the basis of epidemiological evidence, the spread of M. catarrhalis was suggested to occur within the hospital environment [9,10]. McLeod et al [11] reported that 43 of 81 patients (53%) with M. catarrhalis infection were infected in a hospital and that the infection was associated with the proximity of the patient to other patients. Most nosocomial infections with M. catarrhalis involve the respiratory tract and outbreaks have been reported in respiratory units and paediatric intensive care units [10,12].M. catarrhalis infection has received increasing attention because it is an important factor in the acute exacerbation of...

Clinical value of chest computerized tomography scans in patients admitted with pneumonia

“…Other investigators have tried to demonstrate unique or specific findings on CT scans compared to plain radiography for particular pathogens. [11][12][13] We attempted to identify specific features of patients presenting with pneumonia that could assist clinicians in the decision-making process as it relates to ordering a CT scan. CT scans were performed more frequently on subjects who were younger, had lower severity of illness, and were admitted from the community.…”

Clinical characteristics of community-acquired pneumonia due to Moraxella catarrhalis in adults: a retrospective single-centre study

“…Additionally, no past studies have compared the radiological findings of MC-CAP and SP-CAP. Okada et al [ 6 ] investigated 109 CT scans conducted on patients with M. catarrhalis pneumonia (only 34 of 109 patients had CAP) and found that the most common radiological findings were ground glass opacities (91%) followed by bronchial wall thickening (78%), centrilobular nodules (73%), and consolidation (49%). These findings were similar to our findings, suggesting that these findings are characteristic of M. catarrhalis respiratory infection regardless of the pneumonia classification as CAP or hospital-acquired pneumonia.…”

“…In addition, previous studies have not excluded patients co-infected with other respiratory bacteria, so the clinical features of MC-CAP isolated only M. catarrhalis by bacterial culture are unclear [ 4 , 5 ]. In terms of radiological features of MC-CAP, Okada et al [ 6 ] assessed pulmonary computed tomography (CT) findings in patients with acute M. catarrhalis pulmonary infection. However, 75 of 109 patients (68.8%) had nosocomial infection, and radiological findings of MC-CAP were not specifically described.…”

Community‐acquired Pseudomonas aeruginosa pneumonia in previously healthy patients

“…Although various bacterial factors such as surface components, the type III secretion system, quorum sensing, and scavenging of iron and other extracellular products has been reported (Sadikot et al, 2005;Williams et al, 2010), it is possible that the large amount of endotoxin derived from the pathogen led to excessive inflammation and resulted in systemic inflammatory response syndrome in the present case. Okada et al (2012) recently concluded from thin-section CT findings of 29 patients with P. aeruginosa pulmonary infection that ground-glass attenuation or bronchial wall S. Tsuji and others thickening were the main findings, but only nine patients with CAP were included in that study.…”