Streptococcus Anginosus Group Bacteria Research Articles

Intracranial Empyema in Children: A Single-center Retrospective Case Series.

We conducted a retrospective, observational study of 42 children with intracranial empyema admitted to a pediatric neurosurgical center over a 9-year period. Intracranial empyema is rare, but causes significant morbidity and mortality. Twenty-eight cases had neurosurgical source control, more commonly for subdural collections. Streptococcus anginosus group bacteria are important pathogens in subdural empyema, whose isolation predicts more complicated postoperative courses.

Association between obligatory anaerobes and empyema caused by Streptococcus anginosus group bacteria.

Co-infections of Streptococcus anginosus group (SAG) bacteria and obligate anaerobes are observed in patients with empyema; however, their epidemiology and pathology remain unknown. A retrospective study was performed with 44 patients who underwent pleural effusion microbiota evaluation between January 2006 and March 2018, using the clone library method for detecting empyema caused by SAG bacteria. Based on culture analysis of pleural effusion, 12 patients were diagnosed with empyema caused by SAG bacteria. Obligate anaerobe phylotypes were detected in eight patients (66.7%) using the clone library method, whereas anaerobic culture analysis detected anaerobes in only two patients (16.7%). No significant difference was observed between the clinical features of SAG-mediated empyema with and without anaerobes using the clone library method, except for chest computed tomographic data. Co-infection of SAG bacteria and obligate anaerobes may be underestimated if conventional culture methods are used. SAG-mediated empyema with and without anaerobes may present different radiological features; therefore, further studies are required.

Pleural fluid investigations for pleural infections

: Over 1.5 million patients are admitted to hospital with pneumonia in the United States each year. Up to 50% of them can develop a parapneumonic effusion which is associated with higher mortality. The incidence of pleural infection continues to rise, particularly in the elderly and those with comorbidities. Parapneumonic effusions cover a spectrum of presentations from a free-flowing ‘simple parapneumonic effusion’ to a septated ‘complicated parapneumonic effusion’ (CPE) (usually from bacterial pleural invasion) and ‘empyema’ (presence of pleural pus). Pleural infection is defined as either CPE or empyema, and usually requires evacuation of the infected fluid. Laboratory investigations play an essential part of the diagnosis and management of pleural infection. A parapneumonic effusion is typically a neutrophil-rich exudate. Presence of bacteria from culture of the fluid defines pleural infection but conventional culture methods have a low yield. Surrogate pleural fluid markers are often employed to confirm a CPE, including low pleural fluid pH (<7.2) or glucose (<3.3 mmol/L) and elevated lactate dehydrogenase (LDH). Measurement of pleural fluid triglyceride and chylomicrons (for chylothorax) and cholesterol (for pseudochylothorax) may be needed to separate lipid pleural effusions from empyema. Tuberculous pleural effusions usually result from a hypersensitivity pleuritis and are lymphocyte predominant with elevated pleural fluid adenosine deaminase (ADA) and interferon gamma levels. Culture yield of mycobacteria is typically low. Caseating granulomas on pleural tissue biopsy is often considered diagnostic. Common organisms for community-acquired pleural infection include Streptococcus pneumoniae, Streptococcus anginosus group bacteria and Staphylococcus aureus. Hospital-acquired pleural infections have higher mortality and are often polymicrobial which can include S. aureus, Enterobacteriaceae and anaerobes. Antibiotics and evacuation of the infected fluid, usually by chest tube drainage, remain the mainstay of treatment. Intrapleural fibrinolytic and deoxyribonuclease therapy, or occasionally surgical drainage, may be required.

Desarrollo de un medio simple para el aislamiento selectivo de bacterias del grupo Streptococcus anginosus

Bacteria of the Streptococcus anginosus group (SAG) have recently been recognized as contributors of bronchopulmonary disease in cystic fibrosis (CF). Routine detection and quantification are limited by current CF microbiology protocols. The development of the CHROMagar™ StrepB chromogenic medium modified by the addition of plasma, nalidixic acid, colistin and sulfadiazine to make it selective for SAG bacteria is described. This medium could be used as a diagnostic tool to detect SAG in respiratory samples from patients suffering from chronic lung disease.

Streptococcus anginosus group infections: Management and outcome at a tertiary care hospital

BackgroundData on patients with invasive Streptococcus anginosus group (SAG) infections is limited, as it’s been considered commensal bacteria in the human microbiota. We conducted an analysis of SAG infections to assist clinicians in understanding their burden and clinical outcomes. MethodsA retrospective study of medical records, identifying invasive SAG bacteria of sterile-site isolates that were managed from May 2015 to April 2017, at a tertiary care hospital in Riyadh, Saudi Arabia. Demographic data, clinical presentation, site of infection, antibiotic use, and outcome were recorded and analyzed to identify factors associated with poor outcome and/or polymicrobial growth. ResultsWe identified 105 cases of SAG infections in adults, with 52% of the patients being male and the mean age of 52.4 years with comorbidities occurring in more than half of the cases such as diabetes (38%) and malignancy (15%). Overall mortality was 6%, and it was statistically associated with age older than 65 years, polymicrobial growth and a history of malignancy. The infection frequencies were skin and soft tissue infections (SSTI; 55%), intra-abdominal infections (24%), bacteremia (14%), genitourinary infections (8.5%), and pleuropulmonary infections (5%). Abscesses accounted for 68% of cases. Polymicrobial infection (46%) with Enterobacteriaceae and Gram-negative anaerobes coincided with SAG infection. Polymicrobial growth was significantly associated with abscess formation, intra-abdominal source of infections, and poor outcome. In addition, death in patients with SAG was statistically associated with patients older than 65 years of age and those with history of cancer or transplant. ConclusionSSTIs and intra-abdominal infections are the most common clinical presentations in our cohort. Bacteremia was uncommon; however, the prognosis is less favorable. Overall susceptibility to penicillin was 91%, therefore β-lactam antibiotics are the drug of choice and additional coverage for anaerobic and gram-negative bacteria should be considered for intra-abdominal collection and solid or organ abscesses.

Paraparesis and Bilateral Pulmonary Abscesses Secondary to Pyogenic Spondylodiscitis Caused by Streptococcus Anginosus Group Bacteria.

Paraparesis and Bilateral Pulmonary Abscesses Secondary to Pyogenic Spondylodiscitis Caused by Streptococcus Anginosus Group Bacteria.

A case of rapidly progressive empyema caused by Streptococcus anginosus group bacteria in a young male patient

Introduction: The Streptococcus anginosus group bacteria (SAG; formerly Streptococcus milleri) are facultative anaerobes that rarely cause pneumonia but have been increasingly found in empyema. Several reports have suggested that patients with SAG empyema commonly have underlying comorbidities that include diabetes mellitus and malignancy.

Case-control study of pneumonia patients with Streptococcus anginosus group bacteria in their sputum

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. 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. 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. 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.

Bloodstream infections caused by Streptococcus anginosus group bacteria: A retrospective analysis of 78 cases at a Japanese tertiary hospital.

To investigate the characteristics of Streptococcus anginosus group (SAG) bacteremia in recent years, we conducted a retrospective cohort study and compared its findings with the data from previous studies. All patients with positive blood cultures from May 2005 to September 2014 in a tertiary care center with 925 beds were included. There were 78 cases of SAG bacteremia (51 cases men; median age, 68 years) during the study period. The most common comorbidities were solid tumors in 32.1% of the patients. The most common infection source was hepatobiliary in one-third of all cases. Other infection sites included the following: intra-abdominal (12.8%), thoracic (10.3%), musculoskeletal (9%), urinary tract (7.7%), soft tissues (7.7%), and cervicofacial (6.4%). Susceptibility to penicillin, clindamycin and erythromycin were 100% (78/78), 95% (70/74) and 85% (39/46), respectively. Surgery along with systemic antibiotic treatment was administered in 53% of the cases. In-hospital mortality was 14.1%. The clinical sources of the SAG bacteria were diverse, and hepatobiliary infection was the most common source of infection. In more than half of the patients, surgical treatment was performed. Susceptibility to penicillin was 100%, but susceptibility to erythromycin was lower than that reported in previous studies.

Streptococcus anginosus Group Bacteria: No Longer a Case of Mistaken Identity

The anginosus, or “milleri,” group of bacteria belonging to the genus Streptococcus have long been the cause of much consternation with respect to both their nomenclature and accurate laboratory identification. Although they are considered part of the normal flora of the human gastrointestinal, urogenital, and upper respiratory tracts, Streptococcus anginosus group (SAG) bacteria have the ability to cause severe invasive infections with a propensity for abscess formation. Although whole-genome and multilocus sequence analyses of SAG bacteria support the current view that the SAG is made up of three distinct species (S. anginosus, S. constellatus, and S. intermedius) and a number of subspecies, advances in molecular technology have allowed more accurate laboratory identification of SAG bacteria; it remains to be seen whether distinguishing these species and subspecies will be of clinical importance.

Streptococcus anginosus (milleri) Group Strains Isolated in Poland (1996-2012) and their Antibiotic Resistance Patterns.

Streptococcus anginosus, Streptococcus intermedius and Streptococcus constellatus form a group of related streptococcal species, namely the Streptococcus Anginosus Group (SAG). The group, previously called "milleri" had been rarely described until 1980/1990 as source of infections. Nowadays SAG bacteria are often described as pathogens causing predominantly purulent infections. The number of infections is highly underestimated, as SAG strains are often classified in the microbiology laboratory as less virulent "viridans streptococci" Epidemiological situation regarding SAG infections in Poland has been unrecognized, therefore we performed a retrospective analysis of strains isolated between 1996 and 2012. Strains suspected of belonging to SAG were re-identified using an automated biochemical approach (Vitek2) and MALDI-TOF MS. We performed first analysis of antibiotic resistance among SAG strains isolated in Poland using automated methods (Vitek2), disk diffusion tests and E-Tests. We also performed PCR detection of resistance determinants in antibiotic resistant strains. Clonal structure of analyzed strains was evaluated with PFGE and MLVF methods. All three species are difficult to distinguish using automated diagnostic methods and the same is true for automated MIC evaluation. Our analysis revealed SAG strains are rarely isolated in Poland, predominantly from purulent infections. All isolates are very diverse on the genomic level as estimated by PFGE and MLVF analyses. All analyzed strains are sensitive to penicillin, a substantial group of strains is resistant to macrolides and the majority of strains are resistant to tetracycline.

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

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.

Invasive Streptococcus anginosus group infection—does the species predict the outcome?

To determine whether there is an association between the species of Streptococcus anginosus group (SAG) bacteria and the clinical outcome. Isolates from invasive infections caused by SAG bacteria at our institution between January 2004 and February 2009 were identified phenotypically to the taxonomic level of species. Clinical data from the medical records of the patients from whom these isolates were recovered were obtained retrospectively and analyzed. Patients with invasive Streptococcus intermedius infections had a significantly longer hospital stay than patients infected with S. anginosus (p = 0.024) and a significantly higher 30-day all-cause mortality than patients infected with Streptococcus constellatus (p = 0.049). Identification of SAG bacteria to the taxonomic level of species may be of prognostic importance.

The Significance of Streptococcus anginosus Group in Intracranial Complications of Pediatric Rhinosinusitis

To assess the significance of the Streptococcus anginosus group in intracranial complications of pediatric patients with rhinosinusitis. Retrospective cohort study. Tertiary pediatric hospital. A 20-year review of medical records identified patients with intracranial complications resulting from rhinosinusitis. In the 50 cases identified, S anginosus was the most commonly implicated bacterial pathogen in 14 (28%). Documented data included demographics, cultured bacteria, immune status, sinuses involved, type of intracranial complication, otolaryngologic surgical and neurosurgical intervention, type and duration of antibiotics used, and resulting neurologic deficits. Complications and outcomes of cases of S anginosus group-associated rhinosinusitis were compared with those of other bacteria. The severity and outcomes of intracranial complications of pediatric rhinosinusitis due to S anginosus group bacteria compared with other bacteria. Infection caused by the S anginosus group resulted in more severe intracranial complications (P = .001). In addition, patients with S anginosus group-associated infections were more likely to require neurosurgical intervention (P < .001) and develop long-term neurologic deficits (P = .02). Intravenous antibiotics were administered for a longer duration (P < .001) for S anginosus group-associated infections. Rhinosinusitis associated with the S anginosus group should be considered a more serious infection relative to those caused by other pathogens. Streptococcus anginosus group bacteria are significantly more likely than other bacteria to cause more severe intracranial complications and neurologic deficits and to require neurosurgical intervention. A low threshold for intervention should be used for infection caused by this pathogen.

Development of an Ex Vivo Coculture System to Model Pulpal Infection by Streptococcus anginosus Group Bacteria

IntroductionStreptococcus anginosus group (SAG) bacteria are opportunistic pathogens and a major cause of pulpal infection and subsequent abscess formation. Understanding of the processes involved in SAG oral infections has been limited by the lack of an appropriate model system. MethodsCocultures of SAG bacteria and mammalian tooth slices were maintained using a combination of Dulbecco modified eagle medium and brain-heart infusion broth at 60 rpm, 37°C, 5% CO2 for 4, 8, or 24 hours before histologic examination or staining with acridine orange/ethidium bromide. Tooth slices were also incubated as described with SAG bacteria stained with fluorescein diacetate. Pulps were extirpated from infected and sterile cultured tooth slices, messenger RNA was extracted and converted to complementary DNA, and polymerase chain reaction were performed for genes encoding tumor necrosis factor α, interleukin 1β, and interleukin-6. ResultsSAG bacteria were able to adhere directly to the central region of the pulpal matrix in small foci that were associated with a localized matrix breakdown. Acridine orange–ethidium bromide staining and cell counts indicated a decrease in mammalian cell viability with increasing incubation times in the presence of SAG bacteria. The increased expression of tumor necrosis factor α and interleukin 1β was detected in infected tooth slices. ConclusionsA novel ex vivo model system has been developed that allows coculture of SAG bacteria with a 3-dimensional organotypic tooth slice. The model allows observation of bacterial growth patterns and subsequent responses from host tissues. Therefore, it may be of future use in testing the efficacy of both antimicrobial and anti-inflammatory treatments for use in endodontic therapy.

Real-time monitoring of the adherence of Streptococcus anginosus group bacteria to extracellular matrix decorin and biglycan proteoglycans in biofilm formation

Members of the Streptococcus anginosus group (SAGs) are significant pathogens. However, their pathogenic mechanisms are incompletely understood. This study investigates the adherence of SAGs to the matrix proteoglycans decorin and biglycan of soft gingival and alveolar bone. Recombinant chondroitin 4-sulphate(C4S)-conjugated decorin and biglycan were synthesised using mammalian expression systems. C4S-conjugated decorin/biglycan and dermatan sulphate (DS) decorin/biglycan were isolated from ovine alveolar bone and gingival connective tissue, respectively. Using surface plasmon resonance, adherence of the SAGs S. anginosus, Streptococcus constellatus and Streptococcus intermedius to immobilised proteoglycan was assessed as a function of real-time biofilm formation. All isolates adhered to gingival proteoglycan, 59% percent of isolates adhered to alveolar proteoglycans, 70% to recombinant decorin and 76% to recombinant biglycan. Higher adherence was generally noted for S. constellatus and S. intermedius isolates. No differences in adherence were noted between commensal and pathogenic strains to decorin or biglycan. DS demonstrated greater adherence compared to C4S. Removal of the glycosaminoglycan chains with chondroitinase ABC resulted in no or minimal adherence for all isolates. These results suggest that SAGs bind to the extracellular matrix proteoglycans decorin and biglycan, with interaction mediated by the conjugated glycosaminoglycan chain.

KMP044 Antimicrobial susceptibility of Streptococcus anginosus group in Germany

The anginosus, or “milleri,” group of bacteria belonging to the genus Streptococcus have long been the cause of much consternation with respect to both their nomenclature and accurate laboratory identification. Although they are considered part of the normal flora of the human gastrointestinal, urogenital, and upper respiratory tracts, Streptococcus anginosus group (SAG) bacteria have the ability to cause severe invasive infections with a propensity for abscess formation. Although whole-genome and multilocus sequence analyses of SAG bacteria support the current view that the SAG is made up of three distinct species (S. anginosus, S. constellatus, and S. intermedius) and a number of subspecies, advances in molecular technology have allowed more accurate laboratory identification of SAG bacteria; it remains to be seen whether distinguishing these species and subspecies will be of clinical importance.

Pylephlebitis: report of 2 cases

The anginosus, or “milleri,” group of bacteria belonging to the genus Streptococcus have long been the cause of much consternation with respect to both their nomenclature and accurate laboratory identification. Although they are considered part of the normal flora of the human gastrointestinal, urogenital, and upper respiratory tracts, Streptococcus anginosus group (SAG) bacteria have the ability to cause severe invasive infections with a propensity for abscess formation. Although whole-genome and multilocus sequence analyses of SAG bacteria support the current view that the SAG is made up of three distinct species (S. anginosus, S. constellatus, and S. intermedius) and a number of subspecies, advances in molecular technology have allowed more accurate laboratory identification of SAG bacteria; it remains to be seen whether distinguishing these species and subspecies will be of clinical importance.