The clinical features of respiratory infections caused by the Streptococcus anginosus group

Abstract

BackgroundThe Streptococcus anginosus group (SAG) play important roles in respiratory infections. It is ordinarily difficult to distinguish them from contaminations as the causative pathogens of respiratory infections because they are often cultured in respiratory specimens. Therefore, it is important to understand the clinical characteristics and laboratory findings of respiratory infections caused by the SAG members. The aim of this study is to clarify the role of the SAG bacteria in respiratory infections.MethodsA total of 30 patients who were diagnosed with respiratory infections which were caused by the SAG bacteria between January 2005 and February 2015 were retrospectively evaluated.ResultsRespiratory infections caused by the SAG were mostly seen in male patients with comorbid diseases and were typically complicated with pleural effusion. Pleural effusion was observed in 22 (73.3%) patients. Empyema was observed in half of the 22 patients with pleural effusion. S. intermedius, S. constellatus and S. anginosus were detected in 16 (53.3 %), 11 (36.7 %) and 3 (10.0 %) patients, respectively. Six patients had mixed-infections. The duration from the onset of symptoms to the hospital visit was significantly longer in “lung abscess” patients than in “pneumonia” patients among the 24 patients with single infections, but not among the six patients with mixed-infection. The peripheral white blood cell counts of the “pneumonia” patients were higher than those of the “lung abscess” patients and S. intermedius was identified significantly more frequently in patients with pulmonary and pleural infections (pneumonia and lung abscess) than in patients with bacterial pleurisy only. In addition, the patients in whom S. intermedius was cultured were significantly older than those in whom S. constellatus was cultured.ConclusionsRespiratory infections caused by the SAG bacteria tended to be observed more frequently in male patients with comorbid diseases and to more frequently involve purulent formation. In addition, S. intermedius was mainly identified in elderly patients with having pulmonary infection complicated with pleural effusion, and the aspiration of oral secretions may be a risk factor in the formation of empyema thoracis associated with pneumonia due to S. intermedius.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0128-6) contains supplementary material, which is available to authorized users.

Clinical characteristics of patients with bacterial pleuritis in the presence of Streptococcus anginosus group and obligate anaerobes detected by clone library analysis

“…These findings are similar to our previous report on lung abscesses . In addition, our previous report also showed that aspiration of oral secretions might be a risk factor of empyema formation by SAG bacteria, similar to another report showing the importance of aspiration in developing pleural‐thoracic empyema . Collectively, aspiration of SAG may be associated with the pathogenesis of abscess and/or empyema in the respiration infection by SAG bacteria, but further investigation is needed.…”

“…Aerobic and anaerobic cultures of pleural effusion samples were performed using the VITEK 2 apparatus (bioMerieux) with or without the associated API identification strip (bioMerieux), as described previously …”

The Importance of Obligate Anaerobes and the <b><i>Streptococcus anginosus</i></b> Group in Pulmonary Abscess: A Clone Library Analysis Using Bronchoalveolar Lavage Fluid

“…Members of the S. anginosus group are facultative anaerobic pathogens that colonize the upper airways and tend to form pus due to their unique characteristics [14,15,16]. In addition to obligate anaerobes, the S. anginosus group is common in the etiology of patients with lung abscess [2,17,18,19], and it was the second most common bacterial phylotype detected in the present study.…”

Rapid developing empyema by group F beta Streptococcus anginosus group

“…Formation of empyema has three stages: the first stage occurs 2–5 days from untreated pneumonia, second stage occurs 5–10 days after untreated effusion collection and if untreated for 10–21 days, the final stage produces a thick pleural peel to prevent the lungs from re-expanding, thus forming empyema 1 4. Mean time for pus formation in SAG infections is 18 days 11. Other reports found that empyema developed 4–6 weeks after onset of aspiration of bacteria into the lungs 4.…”