Community-acquired methicillin-resistant Staphylococcus aureus pneumonia: radiographic and computed tomography findings

Diagnosis and treatment of community-acquired pneumonia in adults: 2016 clinical practice guidelines by the Chinese Thoracic Society, Chinese Medical Association

Community‐acquired pneumonia (CAP) in adults is an infectious disease with high morbidity in China and the rest of the world. With the changing pattern in the etiological profile of CAP and advances in medical techniques in diagnosis and treatment over time, Chinese Thoracic Society of Chinese Medical Association updated its CAP guideline in 2016 to address the standard management of CAP in Chinese adults. Extensive and comprehensive literature search was made to collect the data and evidence for experts to review and evaluate the level of evidence. Corresponding recommendations are provided appropriately based on the level of evidence. This updated guideline covers comprehensive topics on CAP, including aetiology, antimicrobial resistance profile, diagnosis, empirical and targeted treatments, adjunctive and supportive therapies, as well as prophylaxis. The recommendations may help clinicians manage CAP patients more effectively and efficiently. CAP in pediatric patients and immunocompromised adults is beyond the scope of this guideline. This guideline is only applicable for the immunocompetent CAP patients aged 18 years and older. The recommendations on selection of antimicrobial agents and the dosing regimens are not mandatory. The clinicians are recommended to prescribe and adjust antimicrobial therapies primarily based on their local etiological profile and results of susceptibility testing, with reference to this guideline.

Thoracic Imaging Features of Legionnaire's Disease

Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

Septic Pulmonary Embolism Requiring Critical Care: Clinicoradiological Spectrum, Causative Pathogens and Outcomes

OBJECTIVES:

Septic pulmonary embolism is an uncommon but life-threatening disorder. However, data on patients with septic pulmonary embolism who require critical care have not been well reported. This study elucidated the clinicoradiological spectrum, causative pathogens and outcomes of septic pulmonary embolism in patients requiring critical care.

METHODS:

The electronic medical records of 20 patients with septic pulmonary embolism who required intensive care unit admission between January 2005 and December 2013 were reviewed.

RESULTS:

Multiple organ dysfunction syndrome developed in 85% of the patients, and acute respiratory failure was the most common organ failure (75%). The most common computed tomographic findings included a feeding vessel sign (90%), peripheral nodules without cavities (80%) or with cavities (65%), and peripheral wedge-shaped opacities (75%). The most common primary source of infection was liver abscess (40%), followed by pneumonia (25%). The two most frequent causative pathogens were Klebsiella pneumoniae (50%) and Staphylococcus aureus (35%). Compared with survivors, nonsurvivors had significantly higher serum creatinine, arterial partial pressure of carbon dioxide, and Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, and they were significantly more likely to have acute kidney injury, disseminated intravascular coagulation and lung abscesses. The in-hospital mortality rate was 30%. Pneumonia was the most common cause of death, followed by liver abscess.

CONCLUSIONS:

Patients with septic pulmonary embolism who require critical care, especially those with pneumonia and liver abscess, are associated with high mortality. Early diagnosis, appropriate antibiotic therapy, surgical intervention and respiratory support are essential.

Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

Background

This article discusses the value of high-resolution computed tomography (HRCT) in the diagnosis and treatment of pulmonary infections. Lung infection caused by pathogens is an important cause of death. Traditional methods to treat lung infection involved empirical antibiotic therapy. Thin-slice CT scanning is widely used in the clinical setting, and HRCT scan can very clearly show alveolar and bronchiolar involvement of infection.

Material/Methods

In total, 178 patients with community-acquired pneumonia (CAP) were enrolled. All the patients underwent CT scan, qualified sputum, and blood samples for culture or immunological biochemical tests. CT imaging features, pathogenic bacteria, and treatment results were used for statistical analysis.

Results

In 77 patients with lobar consolidation, the rate of detection was 43.26% (77/178), and in 101 patients with lobular pneumonia it was 56.74% (101/178). In 51 patients, pathogenic bacteria were detected (28.65%, 51/178). Sixteen of 33 patients detected with bacteria had cavities (48.5%, 16/33) and 35 of 145 patients detected with bacteria had no cavities (24.1%, 35/145). The difference between the 2 groups was statistically significant (χ²=7.795, P=0.005). According to the pathogenic bacteria, 38 patients were cured (74.51%, 38/51), and according to the CT imaging features 81 patients were cured (71.05%, 81/114). No statistically significant difference was found between them (χ²=0.209, P=0.647).

Conclusions

Treatment effect of CAP based on HRCT findings is not inferior to treatment effect guided by microbial characterization.

The Significance of Bronchoalveolar Lavage Fluid Cytology in Diagnosing Lung Infiltrates in Children

AIM

The aim of this research is to show why is it important in diagnosing children with lung infiltrates.

METHODS

Our study included 50 children with lung infiltrates during period 2005-2012, and was conducted on Pediatric Clinic of the University Clinical Center Sarajevo. We sent all cytological BAL analyses to the University Clinical Center Sarajevo. Cytology was performed by direct microscopy. BAL cytology was performed by the principle of sending samples for centrifuging, 12000 revolutions during a 10 min Shandon-cyto spin. Then the centrifuged sample is dried in the air during 1-2 hours, and is then dyed under the May-Grünwald-Giemsa staining, and analyzed under the Olympus BX41 microscope.

RESULTS

Nosocomial pneumonia has occurred in 32% children, acquired pneumonia in 38%, and 30% children had a lung infiltrates. 6 (12%) of children were younger then 1 year old, 23 (46%) children were between 1 to 5 years, 14 (28%) of children were between 5 to 10 ages, and 7 (14%) of children were between 10-15 ages. The most of the changes in observed children took place on the right lung, 34%, while 26% occurred on the left side, 22% were normal and 18% changes have affected both lungs, right and left. Percentage of cells in cytological smear in children with BAL were: cylindrical cells 28%, lung macrophage 26%, lymphocytes 17%, detritus 17% and phlegm 12%. Erythrocyte sedimentation rate (ESR) in children with BAL was up to 10-52%, to 50-30%, while ESR after first hour was above 50-18 %.

CONCLUSION

Clinical parameters and local inflammation of the affected lobe are associated with positive bronchoalveolar cytology lavage findings.

The usefulness of low-dose CT scan in elderly patients with suspected acute lower respiratory infection in the emergency room

OBJECTIVE

To evaluate the usefulness of low-dose CT (LDCT) for the diagnosis of acute lower respiratory infection (ALRI) in elderly patients in the emergency room (ER).

METHODS

A total of 160 consecutive patients (mean age: 75.9 ± 9.2 years; range: 60-97 years), who were diagnosed to have ALRI by LDCT in the ER, were enrolled in this study. Initial chest radiograph (CR) and CT patterns of ALRI were analysed, and clinical courses of patients were assessed.

RESULTS

49 patients showed negative CR, in whom the main CT patterns were diffuse bronchial wall thickening (n = 23), ground-glass opacity (n = 6), mixed centrilobular nodules and ground-glass opacity (n = 3), small consolidation (n = 8) or consolidation in the dependent lung (n = 9), while the other 111 patients with the main CT pattern of consolidation demonstrated pulmonary abnormality on CR. Pulmonary oedema (12.5%) and pleural effusion (23.1%) were associated. The rate of hospitalization, care in the intensive care unit, mortality and comorbidity were significantly higher in the CR(+)LDCT(+) group (88.3%, 36.1%, 18.2% and 59.5%) than in the CR(-)LDCT(+) group (55.1%, 8.2%, 2.0% and 38.8%; p ≤ 0.05).

CONCLUSION

LDCT was useful for the early diagnosis of ALRI in elderly patients who showed negative initial CR. The patients with negative initial CR had main CT patterns of diffuse bronchial wall thickening, ground-glass opacity, centrilobular nodules, small consolidation or consolidation in the dependent lung on LDCT.

ADVANCES IN KNOWLEDGE

The use of LDCT may be considered for the early diagnosis of ALRI in elderly patients who have high comorbidity.

Imaging pneumonia in immunocompetent and immunocompromised individuals

PURPOSE OF REVIEW

The article aims to indicate the current role of radiological imaging in immune competent and immunocompromised patients with pneumonia. The radiological findings in the most common conditions will be reviewed.

RECENT FINDINGS

Three basic patterns of radiographic abnormality are recognized: lobar (nonsegmental) pneumonia; bronchopneumonia (lobular pneumonia); and interstitial pneumonia. The chest radiograph remains the initial radiological investigation. Computed tomography (CT) is more sensitive than the chest radiograph. The appearances on CT with certain infections such as mycoplasma, invasive aspergillosis, and pneumocystis, in the appropriate clinical setting, may allow a treatment decision to be made when obtaining fluid or tissue for culture is problematical. MRI technology is advancing and this technique may provide an option for follow-up of chronic disease in younger patients in whom radiation exposure is a concern, but MRI does not yet match CT as a diagnostic test in this field.

SUMMARY

Radiology retains a key role in diagnosing pneumonia, excluding pneumonia, following up patients to check for resolution and to evaluate potential complications. The chest radiograph remains the initial examination. CT is more sensitive and with certain infections more specific. MRI provides an option for monitoring progress, although cannot yet match CT as an initial diagnostic test.

Meticillin-resistant Staphylococcus aureus and meticillin-susceptible S. aureus pneumonia: comparison of clinical and thin-section CT findings

OBJECTIVES

The purpose of this study was to compare the clinical and thin-section CT findings in patients with meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-susceptible S. aureus (MSSA).

METHODS

We retrospectively identified 201 patients with acute MRSA pneumonia and 164 patients with acute MSSA pneumonia who had undergone chest thin-section CT examinations between January 2004 and March 2009. Patients with concurrent infectious disease were excluded from our study. Consequently, our study group comprised 68 patients with MRSA pneumonia (37 male, 31 female) and 83 patients with MSSA pneumonia (32 male, 51 female). Clinical findings in the patients were assessed. Parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed.

RESULTS

Underlying diseases such as cardiovascular were significantly more frequent in the patients with MRSA pneumonia than in those with MSSA pneumonia. CT findings of centrilobular nodules, centrilobular nodules with a tree-in-bud pattern, and bronchial wall thickening were significantly more frequent in the patients with MSSA pneumonia than those with MRSA pneumonia (p = 0.038, p = 0.007 and p = 0.039, respectively). In the group with MRSA, parenchymal abnormalities were observed to be mainly peripherally distributed and the frequency was significantly higher than in the MSSA group (p = 0.028). Pleural effusion was significantly more frequent in the patients with MRSA pneumonia than those with MSSA pneumonia (p = 0.002).

CONCLUSIONS

Findings from the evaluation of thin-section CT manifestations of pneumonia may be useful to distinguish between patients with acute MRSA pneumonia and those with MSSA pneumonia.

Bacterial pneumonia following cytotoxic chemotherapy for lung cancer: clinical features, treatment outcome and prognostic factors

Data regarding treatment outcomes and prognosis in pneumonia that occurs after lung cancer chemotherapy are lacking. We performed a retrospective study of 84 patients with clinically suspected bacterial pneumonia after cytotoxic chemotherapy for lung cancer. Small cell carcinoma was the most common histological type (36.9%, n = 31), followed by squamous cell carcinoma (35.7%, n = 30) and adenocarcinoma (21.4%, n = 18). The most frequent pathogen was Streptococcus pneumoniae (n = 14), followed by Klebsiella pneumoniae (n = 10), Staphylococcus aureus (n = 8), and Pseudomonas aeruginosa (n = 7). Of 84 patients, treatment outcome was determined for 80; the outcome was success in 52 (61.9%) and failure in 28 (33.3%); outcome remained undetermined for 4 patients (4.8%). Based on multivariate analysis, tachypnoea (respiratory rate ≥20/min) was the only significant predictor of treatment failure (odds ratio 4.79, 95% confidence interval 1.17-19.70; p = 0.030). In conclusion, bacterial pneumonia after cytotoxic chemotherapy for lung cancer was found to be caused more often by S. pneumoniae and K. pneumoniae than P. aeruginosa, and treatment failure leading to death was found to be high. Tachypnoea was independently associated with treatment failure in this population.

Radiological findings of community-acquired methicillin-resistant and methicillin-susceptible Staphylococcus aureus pediatric pneumonia in Hawaii

BACKGROUND

Community-acquired Staphylococcus aureus (CA-SA) infections are common among pediatric patients in Hawaii.

OBJECTIVE

We wanted to characterize the radiological features of methicillin-susceptible (CA-MSSA) and methicillin-resistant (CA-MRSA) staphylococcal pneumonia in Hawaiian children.

MATERIALS AND METHODS

We retrospectively reviewed medical records and imaging studies of children with SA pneumonia identified from 1996 through 2007.

RESULTS

Of 40 children, 26 (65%) had CA-MRSA pneumonia and 14 patients (35%) had CA-MSSA pneumonia. CA-MRSA patients were significantly younger than CA-MSSA patients (65% younger than 1 year vs. 36% older). In a majority (62%) of CA-MRSA patients, the consolidation was unilateral; in most of the CA-MSSA cases (79%), the consolidation was bilateral. Fifty percent of the patients with CA-MRSA and 21% of those with CA-MSSA had pneumatoceles (P = 0.1). CA-MRSA patients more commonly had pleural effusions (85% vs. 64% for CA-MSSA) and pleural thickening (50% vs. 36% for CA-MSSA).

CONCLUSION

This case series describes the radiologic characteristics of CA-MRSA and CA-MSSA pneumonia in children in a highly endemic area. We found that CA-MRSA pneumonias are unilateral in a majority of pediatric pneumonia cases, are more common in children 1 year or younger, and have higher rates of complications in comparison to CA-MSSA patients.

Acute Klebsiella pneumoniae pneumonia alone and with concurrent infection: comparison of clinical and thin-section CT findings

The purpose of this study was to identify the clinical and thin-section CT findings in patients with acute Klebsiella pneumoniae pneumonia (KPP) alone and with concurrent infection. We retrospectively identified 160 patients with acute KPP who underwent chest thin-section CT examinations between August 1998 and August 2008 at our institution. The study group comprised 80 patients (54 male, 26 female; age range 18-97 years, mean age 61.5) with acute KPP alone, 55 (43 male, 12 female; age range 46-92 years, mean age 76.0) with KPP combined with methicillin-resistant Staphylococcus aureus (MRSA) and 25 (23 male, 2 female; age range 56-91 years, mean age 72.7) with KPP combined with Pseudomonas aeruginosa (PA). Underlying diseases in patients with each type of pneumonia were assessed. Parenchymal abnormalities were evaluated along with enlarged lymph nodes and pleural effusion. In patients with concurrent pneumonia, underlying conditions such as cardiac diseases, diabetes mellitus and malignancy were significantly more frequent than in patients with KPP alone. The mortality rate in patients with KPP combined with MRSA or PA was significantly higher than in those with KPP alone. In concurrent KPP, CT findings of centrilobular nodules, bronchial wall thickening, cavity, bronchiectasis, nodules and pleural effusion were significantly more frequent with concurrent pneumonia than in those with KPP alone.

Case studies of lower respiratory tract infections: community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common and potentially serious illness with significant human and economic costs to society. The recent collaborative statement from the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) represents the most up-to-date evidence-based guidelines from North America, incorporating important advances in the management of patients with CAP. The cases presented in this review highlight many of the recent recommendations from the IDSA/ATS guidelines.