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Case-control study of pneumonia patients with Streptococcus anginosus group bacteria in their sputum
Jun Hirai1, Daisuke Sakanashi2, Shusaku Haranaga3
1Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Japan; Department of Infection Control and Prevention, Aichi Medical University Hospital, Japan; Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan.
Background And Objective:
In recent years, Streptococcus anginosus group (SAG) bacteria are becoming increasingly recognized as important pneumonia-causing pathogens. Although several small studies have been reported, the features of SAG pneumonia remain unclear, because the identification of SAG from sputum cultures is not routinely performed in most microbiology laboratories. The aim of this study was to elucidate the clinical characteristics of SAG pneumonia.
Patient And Methods:
This was a retrospective case-control study utilizing data obtained in our hospital between September 2009 and June 2016. We investigated 31 patients with SAG pneumonia (PWP), and also assessed the difference between the 31 PWP and 37 patients without pneumonia (PWOP) in whose sputum SAG was detected.
Results:
Seventy-one percent of the patients were men and the median age was 78 years in the PWP. Univariate analysis indicated that the PWP were significantly more often a bed-ridden (p < 0.01) with comorbid aspiration than were the PWOP (p < 0.05). Among the PWP, nursing and healthcare-associated pneumonia (NHCAP) was the more common type of pneumonia (54.8%). S. anginosus was detected significantly more frequently in sputum cultures of PWP than PWOP (p < 0.01), and multiple pathogens were detected more frequently in PWP (p < 0.01). Streptococcus constellatus was the most frequently detected pathogen in patients with a single bacterial infection. Empyema was observed only in patients with multiple bacteria.
Conclusions:
SAG should be recognized as important causative pathogens of pneumonia, particularly among elderly patients with underlying disease associated with aspiration. NHCAP was the more common type of SAG pneumonia in this study.
Insights
Streptococcus anginosus group (SAG) bacteria are a significant cause of pneumonia, especially in elderly patients with aspiration risks. Nursing and healthcare-associated pneumonia (NHCAP) is a common type of SAG pneumonia.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Pulmonology
Background:
- Streptococcus anginosus group (SAG) bacteria are increasingly recognized as significant pneumonia pathogens.
- Clinical features of SAG pneumonia remain unclear due to infrequent routine identification in microbiology labs.
- This study aimed to clarify the clinical characteristics of SAG pneumonia.
Purpose of the Study:
- To elucidate the clinical characteristics of Streptococcus anginosus group (SAG) pneumonia.
- To identify risk factors and common types of SAG pneumonia.
- To highlight the importance of SAG as a causative agent of pneumonia.
Main Methods:
- Retrospective case-control study.
- Data collected from September 2009 to June 2016.
- Compared 31 patients with SAG pneumonia (PWP) to 37 patients without pneumonia (PWOP) but with SAG detected in sputum.
Main Results:
- PWP patients were significantly more likely to be bed-ridden and have comorbid aspiration.
- Nursing and healthcare-associated pneumonia (NHCAP) was the most common type (54.8%) in PWP.
- Multiple pathogens were more frequent in PWP, and empyema occurred only in these cases.
Conclusions:
- SAG bacteria should be recognized as important pneumonia pathogens, particularly in the elderly with aspiration-related conditions.
- NHCAP is a prevalent form of SAG pneumonia.
- Accurate identification of SAG is crucial for understanding and managing pneumonia.
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