Streptococcus Anginosus Group Infection Research Articles

Increasing Incidence of Streptococcus anginosus Group Intracranial Infections Associated With Sinusitis, Otitis Media, and Mastoiditis in Children.

The Streptococcus anginosus group (SAG) pathogens have the potential to cause head and neck space infections, including intracranial abscesses. Several centers noted an increase in intracranial abscesses in children during the SARS-CoV-2 pandemic, prompting a Centers for Disease Control and Prevention health alert in May 2022. We examined the epidemiology of pediatric intracranial abscesses at a tertiary care center with a focus on SAG pre- and post-pandemic. Cases of intracranial abscesses of any microbiologic etiology admitted from January 2011 to December 2022 were identified using International Classification of Diseases 10 codes. Subjects were cross-referenced with culture results from the microbiology laboratory at Texas Children's Hospital. Cases included were those associated with either otitis media, mastoiditis or sinusitis and medical records were reviewed. A total of 157 cases were identified and 59.9% (n = 94) were caused by SAG. The incidence of all sinogenic/otogenic intracranial infections ( P = 0.002), and SAG-specific infections ( P = 0.004), increased from 2011 to 2022. SAG infection was more often associated with multiple surgeries, and these subjects were more likely to require craniotomy or craniectomy. Among sinogenic abscesses, S. intermedius was the most common pathogen, while among otogenic cases, S. pyogenes predominated. From March 2020 to Dec 2022, 9/49 cases tested positive for SARS-CoV-2 (18.4%); characteristics of infection were not significantly different among cases with and without SARS-CoV-2. Over the last decade, intracranial complications of sinusitis/otitis have been increasing, specifically those caused by SAG; this trend, however, predated the SARS-CoV-2 pandemic. SAG was associated with a greater need for surgical intervention, specifically neurosurgery. Further work is necessary to determine the cause for these rising infections.

1692. Increasing incidence of Streptococcus anginosus group intracranial complications of sinusitis, otitis media and mastoiditis in a pediatric population

Abstract Background The Streptococcus anginosus group (SAG) pathogens (S. anginosus, S. intermedius, and S. constellatus) are oral flora with the potential to cause head and neck space infections including brain abscesses. Several centers noted an increase in intracranial abscesses in children in the SARS-CoV-2 era, prompting a CDC health alert in May 2022. Notably, a large proportion of such reported cases were associated with SAG and/or sinusitis. We examined the epidemiology of pediatric intracranial abscesses with a focus on SAG in the pre- and post-pandemic periods. Methods Cases of intracranial abscesses (parenchymal, subdural, epidural) of any microbiologic etiology from January 1, 2011 to December 31, 2022 were identified at Texas Children's Hospital by ICD10 codes. Subjects were cross referenced with culture results of the microbiology laboratory. Cases included were those associated with either otitis media, mastoiditis, or sinusitis. Temporal trend in these infections was investigated with linear regression. Results 157 cases were identified and 59.9% were due to SAG. The incidence of all sinogenic/otogenic intracranial infections (p=0.006), and SAG specific infections (p=0.01), increased from 2011 to 2022 (Figure 1). SAG infection was more often associated with multiple surgeries and these subjects were specifically more likely to require craniotomy or craniectomy (Figure 2). Among sinogenic abscesses, S. intermedius was the most common pathogen while among otogenic cases S. pyogenes predominated (Figure 3). There were 8 cases of craniectomies and one relapse (due to SAG) after replacement of autologous bone flap. After March 2020, 6/46 cases tested positive for SARS-CoV-2 (13%); the severity of infection was not significantly different with concomitant COVID and intracranial abscess. The proportion of SAG-associated infections was similar prior to and after the COVID pandemic. *- p= 0.01- <0.05 ** p< 0.01 Conclusion Over the last decade, intracranial complications of sinusitis/otitis have been increasing, and specifically those caused by SAG. This observed trend clearly predated the COVID pandemic. SAG cases were associated with greater need for surgical intervention and specifically neurosurgery. Further work is necessary to determine the explanation for these rising infections. Disclosures Sheldon L. Kaplan, MD, MeMed: Grant/Research Support|Pfizer: Grant/Research Support|Pfizer: Honoraria Jonathon C. McNeil, MD, Allergan: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support

Clinical characteristics and mortality rates of bacteremia caused by Streptococcus anginosus group: A retrospective study of 84 cases at a tertiary hospital in South Korea

The Streptococcus anginosus group (SAG) is a subgroup of viridans streptococci comprising three species: S. anginosus, S. constellatus, and S. intermedius. SAG usually resides in the oral cavity and colonizes the throat, and the gastrointestinal and genitourinary tracts. SAG can form abscesses in various parts of the body; however, the clinical features of SAG infection are not clear. Here, we reviewed the medical records of all SAG bacteremia patients aged over 18 years who were diagnosed between January 2010 and December 2021 at a tertiary university hospital. We then compared clinical characteristics, source of infection, need for surgical or interventional treatment, and 28-day mortality rates among each species of SAG. Differences in percentages between groups were compared using a proportion test, and differences between mean values were assessed using the Kruskal-Wallis test with post-hoc Bonferroni correction. In total, 84 cases of SAG bacteremia (40 S. anginosus cases, 31 S. constellatus cases, and 13 S. intermedius cases) were identified. The most common comorbidity was diabetes mellitus (n = 26, 31%), and the most common source was hepatobiliary infection (n = 30, 35.7%). Polymicrobial bacteremia was observed in 22.6% (19/84) of cases. Twenty-eight day mortality due to S. anginosus bacteremia was 12.5%; no deaths were reported in the S. constellatus and S. intermedius groups. However, the difference among the groups was not significant (p = 0.054). Hepatobiliary infection was the most common source of SAG bacteremia. In addition, S. anginosus bacteremia resulted in more severe disease and higher mortality rates than S. constellatus or S. intermedius bacteremia.

Virulence factors of Streptococcus anginosus – a molecular perspective

Streptococcus anginosus together with S. constellatus and S. intermedius constitute the Streptococcus anginosus group (SAG), until recently considered to be benign commensals of the human mucosa isolated predominantly from oral cavity, but also from upper respiratory, intestinal, and urogenital tracts. For years the virulence potential of SAG was underestimated, mainly due to complications in correct species identification and their assignment to the physiological microbiota. Still, SAG representatives have been associated with purulent infections at oral and non-oral sites resulting in abscesses formation and empyema. Also, life threatening blood infections caused by SAG have been reported. However, the understanding of SAG as potential pathogen is only fragmentary, albeit certain aspects of SAG infection seem sufficiently well described to deserve a systematic overview. In this review we summarize the current state of knowledge of the S. anginosus pathogenicity factors and their mechanisms of action.

The Clinical View on Streptococcus anginosus Group – Opportunistic Pathogens Coming Out of Hiding

Three distinct streptococcal species: Streptococcus anginosus, Streptococcus intermedius, and Streptococcus constellatus, belonging to the Streptococcus anginosus group (SAG), also known as Streptococcus milleri group, have been attracting clinicians and microbiologists, not only as oral commensals but also as opportunistic pathogens. For years they have been simply classified as so called viridans streptococci, and distinct species were not associated with particular clinical manifestations. Therefore, description of SAG members are clearly underrepresented in the literature, compared to other medically relevant streptococci. However, the increasing number of reports of life-threatening infections caused by SAG indicates their emerging pathogenicity. The improved clinical data generated with the application of modern molecular diagnostic techniques allow for precise identification of individual species belonging to SAG. This review summarizes clinical reports on SAG infections and systematizes data on the occurrence of individual species at the site of infection. We also discuss the issue of proper microbiological diagnostics, which is crucial for further clinical treatment.

Streptococcus anginosus group infections in hospitalised children and young people.

The Streptococcus anginosus group (SAG) comprises three bacterial species colonising the mouth and gastrointestinal and genitourinary tracts and capable of serious pyogenic infections. Although well-described in adults, studies in children are limited. Here, we characterise paediatric SAG infections from a single Australian centre. Hospitalised patients aged ≤18 years with positive SAG cultures from January 2009 to December 2019 were identified from Pathology Queensland's Gold Coast Laboratory database and their medical records were reviewed. Two-hundred children (62% male), median age 12 years (interquartile range 6-16), with positive SAG cultures were identified. Overall, 90% received intravenous antibiotics, 89% underwent surgical drainage, 23% were readmitted and 15% required additional surgery. The most common sites were the abdomen (39%), soft tissues (36%) and head and neck regions (21%). Since 2011, Pathology Queensland reported SAG at the species level (n=133). Of these, S. anginosus was the most prevalent (39%), then S. constellatus (34%) and S. intermedius (27%). Compared with the other two species, S. intermedius was most commonly associated with head and neck infections (relative risk (RR)=2.2, 95% confidence interval (CI) 1.4-3.5), while S. constellatus (RR=1.7, 95% CI 1.2-2.4) and S. anginosus (RR=1.5, 95% CI 1.0-2.0) were each associated with a higher risk of intra-abdominal infection than S. intermedius. Since February 2015, the number of children admitted with SAG-associated intra-abdominal infection per 1000 hospitalisations increased by 29% annually compared with an annual decline of 8% in previous years. SAG infections occur at various anatomical sites. Despite antibiotics and surgical management, almost one-quarter are re-hospitalised for further treatment.

Streptococcus anginosus group infection as a predictor for the progression of descending necrotizing mediastinitis

The prognosis of descending necrotizing mediastinitis (DNM), especially that extending inferiorly to the carina, remains poor. The identification of additional prognostic factors may improve the prognosis. We retrospectively analyzed six patients who underwent thoracic surgery for DNM extending to the anterior and posterior mediastinum inferior to the carina (Endo classification type IIB) from 2014 to 2020. We reviewed their characteristics, clinical course, causative bacteria, and treatment to investigate their prognostic factors. The median patient age was 62 years. Five patients were men and one patient was a woman. The causative disease in three of the patients was pharyngolaryngeal, and for the others, it was an odontogenic infection. Five patients had sepsis and four had disseminated intravascular coagulation (DIC) at surgery. Four patients had polymicrobial infections of aerobic and anaerobic bacteria, all of whom showed gas bubbles on a chest computed tomography scan and detection of Streptococcus anginosus group (SAG). All patients underwent cervicotomy, tracheostomy, and mediastinal drainage and debridement via a transthoracic approach. Three patients underwent additional surgery or drainage because an additional abscess appeared postoperatively. The median duration of hospitalization was 58 days and the mixed infections, including SAG, were all detected in the three cases of long-term hospitalization. No disease-associated death was observed during the follow-up period of 18 months. Mixed infection, including SAG, may be a predictor for DNM aggravation and spread. Gas bubbles on a chest computed tomography scan suggest polymicrobial aerobic and anaerobic infections including SAG, which require broad-spectrum antibiotic therapy and aggressive drainage and surgery.

#39: Streptococcus anginosus Group Infections in Children: A Retrospective Cohort Study, 2015–2019

Abstract Background Infections attributed to the Streptococcus anginosus group (SAG), which includes Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius, have varying clinical presentations. SAG infections are difficult to identify initially, and members of the group may require different management strategies. Methods A retrospective review of SAG-positive cultures from January 2015, to September 2019, was conducted to describe the demographic, clinical, and laboratory features including the site of infection, antibiotic susceptibility, management, and clinical outcome. Results We identified 561 patients [median age 11.3, interquartile range (IQR) 7.1–14.9 years, male:female ratio 3:2, non-Hispanic–non-Latino 454 (81%), White 279 (49%)]. Thirty-nine (7%) had at least one underlying condition. Of these, inflammatory bowel disease 15 (39%), diabetes 7 (18%), immunodeficiency 5 (13%). SAG was found in exudate, fluid, or aspirate (537/561, 96%), blood (11/561, 2%), and tissue (11/561, 2%) samples; 388 (69%) were polymicrobial infections. The most common site of infection was intra-abdominal (175, 31%), followed by neck/odontogenic (114. 20%) and genitourinary tract (66, 12%). The median length of stay was 6 days (IQR 3–10 days) and was statistically significantly longer for patients with blood, central nervous system, and pulmonary infections compared with soft tissue and upper respiratory tract infections (P < 0.001). Beta-lactams were the most commonly used antibiotics (38%), followed by clindamycin (30 %) (see Figure for antibiotic susceptibility results) and 33 (56%) patients received combination therapy. We did not observe any SAG attributed to mortality. Conclusions In our retrospective cohort, SAG infections were more commonly identified in males, were associated with abscess formation, and presented as polymicrobial infections. Children with underlying comorbidities are more likely to present with systemic SAG infections. SAG-associated infections can be variable in presentation site and severity and should be considered as pathogens when managing patients.

Microbiology of orbital cellulitis with subperiosteal abscess in children: Prevalence and characteristics of Streptococcus anginosus group infection

ABSTRACT Purpose To evaluate the predominant pathogens and clinical course in pediatric patients with orbital cellulitis (OC) complicated by subperiosteal abscess (SPA). Methods This is a single-center retrospective chart review evaluating pediatric patients with OC complicated by SPA treated at a tertiary care center in the Pacific Northwest. Data were analyzed for characteristics, rates of infection, and antibiotic resistance of the predominant pathogens in pediatric patients. Results Twenty-seven children were identified with OC complicated by SPA and bacterial cultures drawn. The average age (SD) of the patients was 9.2 years (4.8), median 9.6; 15 range 5 months to 17.2 years. Seventeen (63.0%) were male. Sinusitis was present in all patients. Streptococcus species were the most common pathogen accounting for 52% (17/33) of isolates. Streptococcus anginosus group (SAG) was the predominant species and were isolated in 10 out of 27 (37%) children in the study. Twenty-one (78%) patients required surgery for the treatment of SPA. Among surgically treated patients, females tended to be younger than males (p = .068). Pediatric patients with SAG infections required more surgery than children without this isolate, 100% and 65%, respectively (p = .030). Female patients tended to have SAG infections more often than males (p = .063). Conclusions Orbital infections caused by SAG require surgical management more often than those caused by other pathogens. Our results suggest a difference in pathogenic organisms in male and female patients with SPA. SAG is one of the most common pathogens isolated in orbital cellulitis complicated by SPA in children.

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.

Streptococcus anginosus Group Bacterial Infections

BackgroundThe Streptococcus anginosus group (SAG) causes a variety of infections in adults. To better understand the burden of SAG infections and their associated morbidity and mortality, we conducted a retrospective analysis of these infections in adults at a tertiary care center. MethodsA retrospective review of all cultures positive for SAG in adults and a corresponding review of the patients’ medical records were conducted at a tertiary care facility in central New York. Patients with these cultures during the period of January 2007-December 2011 were included. Demographic data, area of residence, clinical features and underlying illnesses, site of infection, length of hospital stay, antibiotic susceptibility and antibiotic therapy were recorded and analyzed. ResultsThere were 332 SAG cases; most patients were males (59%), mean age of 47 years and 84% lived in urban areas. Overall mortality was 3% with underlying conditions common such as diabetes (25%), hypertension (31%) and immunodeficiency (22%). Most of the infections were related to skin and soft tissue (72%) and polymicrobial (70%) with gram-negative anaerobes and Enterobacteriaceae commonly isolated with SAG. ConclusionsWe present the largest study, thus far, reviewing the clinical presentation, management and outcome of infections due to the SAG of organisms. Notable findings from our study are the low mortality associated with SAG infection, and the propensity to present as a skin and tissue and polymicrobial infection. Our findings will assist clinicians in managing patients with SAG infections and recognizing that S anginosus may be one of several organisms responsible for infection.

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.

Cerebritis bifrontal y absceso cerebral por Streptococcus del grupo anginosus, en paciente previamente sano: Caso clínico

The etiology of brain abscesses is mostly polymicrobial. Streptococci and anaerobic bacteria are the most commonly isolated pathogens. We report a previously healthy female without predisposing factors, presenting with a bifrontal cerebritis caused by a Streptococcus anginosus group infection. The patient developed a brain abscess and a subdural collection with severe intracranial hypertension of fatal evolution. The etiologic diagnosis was made culturing the material obtained from the subdural collection. It is presumed that, within the Streptococcus anginosus group, Streptococus intermedius could have been the causing bacteria, given its central nervous system tissue tropism and its predisposition to form brain abscesses.

Prevalence of erythromycin and clindamycin resistance among clinical isolates of the Streptococcus anginosus group in Germany

Members of the Streptococcus anginosus group (SAG) are frequently involved in pyogenic infections in humans. In the present study, the antimicrobial susceptibility of 141 clinical SAG isolates to six antimicrobial agents was analysed by agar dilution. All isolates were susceptible to penicillin, cefotaxime and vancomycin. However, 12.8 % displayed increased MIC values (0.12 mg l(-1)) for penicillin. Resistance to erythromycin was detected in eight (5.7 %) isolates. Characterization of the erythromycin-resistant isolates with the double-disc diffusion test revealed Macrolide-Lincosamide-Streptogramin(B) and M-type resistance in six and two isolates, respectively. The erythromycin-resistant isolates were further characterized by PCR for the resistance genes ermA, ermB and mefA. Resistance and intermediate resistance to ciprofloxacin were detected in two and six isolates, respectively. Molecular typing by PFGE revealed a high genetic heterogeneity among the SAG isolates and no evidence for a clonal relationship between the erythromycin-resistant isolates. Our data show that resistance to erythromycin, clindamycin and ciprofloxacin has emerged among SAG isolates in Germany. The implications of these findings for susceptibility testing and antimicrobial therapy of SAG infections are discussed.