A secondary abdominal aorta-duodenal fistula accompanied with acquired Immune Deficiency Syndrome presented with recurrent sepsis: a case report.

BACKGROUND: Abdominal aorta-duodenal fistulas are rare abnormal communications between the abdominal aorta and duodenum. Secondary abdominal aorta-duodenal fistulas often result from endovascular surgery for aneurysms and can present as severe late complications. CASE PRESENTATION: A 50-year-old male patient underwent endovascular reconstruction for an infrarenal abdominal aortic pseudoaneurysm. Prior to the operation, he was diagnosed with Acquired Immune Deficiency Syndrome and Syphilis. Two years later, he was readmitted with lower extremity pain and fever. Blood cultures grew Enterococcus faecium, Salmonella, and Streptococcus anginosus. Sepsis was successfully treated with comprehensive anti-infective therapy. He was readmitted 6 months later, with blood cultures growing Enterococcus faecium and Escherichia coli. Although computed tomography did not show contrast agent leakage, we suspected an abdominal aorta-duodenal fistula. Esophagogastroduodenoscopy confirmed this suspicion. The patient underwent in situ abdominal aortic repair and received long-term antibiotic therapy. He remained symptom-free during a year and a half of follow-up. CONCLUSIONS: This case suggests that recurrent infections with non-typhoidal Salmonella and gut bacteria may be an initial clue to secondary abdominal aorta-duodenal fistula.

Purulent Pericarditis as the First Manifestation of Esophageal Carcinoma.

INTRODUCTION: Purulent pericarditis secondary to esophago-pericardial fistula is a serious complication that has been previously reported in patients with esophageal cancer treated with radio/chemotherapy and esophageal stenting. However, the presence of esophago-pericardial fistula as the first manifestation of advanced carcinoma of the esophagus is exceedingly infrequent. We report the case of a 61-year-old male who presented with sepsis, cardiac tamponade and septic shock who was found to have an esophago-pericardial fistula secondary to squamous carcinoma of the esophagus. Emergency pericardiocentesis was performed with subsequent hemodynamic improvement. The drained pericardial fluid was purulent in nature and cultures were positive for Streptococcus anginosus. A CT scan followed by upper gastrointestinal endoscopy with tissue biopsy confirmed the diagnosis of squamous cell carcinoma of the esophagus. A self-expanding covered stent was endoscopically placed to exclude the fistula and restore the esophageal lumen. In this report, we discuss some aspects related to the diagnosis and management of this serious clinical entity.

Characterization of erm(B)-Carrying Integrative and Conjugative Elements Transferred from Streptococcus anginosus to Other Streptococci and Enterococci.

Integrative and conjugative elements (ICEs) are important vectors of lateral gene transfer and contribute to the evolution of bacterial pathogens. However, studies on the transfer among species and the physiological consequences of ICEs are rare. The objective of this study was to investigate the cross-species transferability of newly identified erm(B)-carried ICE in Streptococcus anginosus San95 and its physiological consequences after transfer. The erm(B)-carried ICE, characterized by a triple serine integrase module, integrated into hsdM genes, thus designated ICESan95_hsdM. Analysis of ICESan95_hsdM revealed 32 additional ICESan95-like ICEs in the available NCBI genome (n = 24) and sequence of clinical isolates (n = 8). Polymerase chain reaction (PCR) was used to evaluate the 467 clinical isolates, of which 84 were positive for core genes (integrase, relaxase, and T4SS genes) of ICESan95_hsdM. Cross-species transfer experiments demonstrated that ICESan95_hsdM could transfer from S. anginosus to different streptococcal and enterococcal recipients. Growth and competitive culture assays showed acquisition of ICESan95_hsdM incurred no fitness cost. Our work discovered a group of ICEs in Streptococci and Enterococci. For the first time, we demonstrated the broad cross-species transferability to different species or genera of ICEs with no fitness cost that enables commensal S. anginosus to deliver antimicrobial resistance genes to other streptococci and enterococci.

Antimicrobial activity of eravacycline and other comparative agents on aerobic and anaerobic bacterial pathogens in Taiwan: A clinical microbiological study.

OBJECTIVES: Eravacycline, a new tetracycline derivative, exhibits broad-spectrum antimicrobial susceptibility. This study aimed to comprehensively investigate in vitro activities of eravacycline, tigecycline, and ertapenem against various Gram-positive, Gram-negative, and anaerobic bacteria. METHODS: Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. The following bacterial species were collected: vancomycin-sensitive (VS) Enterococci species, vancomycin-resistant Enterococci species (VRE), Staphylococcus aureus, Streptococcus anginosus, Bacteroides species, Clostridioides difficile, Clostridium innocuum, Clostridium perfringens, Parabacteroides distasonis, and Stenotrophomonas maltophilia. RESULTS: We found that eravacycline exhibited superior in vitro activity compared to tigecycline and ertapenem. Notably, it exhibited the lowest MIC90 for several bacterial species, including VS E. faecalis (0.12 µg/mL), VS E. faecium (0.12 µg/mL), and others. Besides, VRE was susceptible to eravacycline (MIC90:0.12 µg/mL) and tigecycline (MIC90:0.12 µg/mL), but was all resistant to ertapenem (MIC90 > 64 µg/mL). S. aureus was also susceptible to eravacycline (MIC90:0.5 µg/mL) as well as tigecycline (MIC90:1.0 µg/mL). Furthermore, S. anginosus showed higher susceptibility to eravacycline (MIC90:2.0 µg/mL) and tigecycline (MIC90:4.0 µg/mL), but lower to ertapenem (MIC90:32.0 µg/mL). Eravacycline and tigecycline also demonstrated good susceptibility to anaerobes, including Bacteroides species (susceptibility rate: 100%), P. distasonis (100%), C. difficile (94.1‒100%), C. innocuum (94.1‒96.1%), and C. perfringens (88.9‒96.3%). For S. maltophilia, both tigecycline and eravacycline showed an MIC90 of 2 µg/mL. A moderate-to-strong correlation (rho = 0.608-0.804, P < 0.001) was noted between the MIC values of eravacycline and tigecycline against various bacterial species. CONCLUSIONS: Our study highlights the potential of eravacycline as an effective treatment option for multidrug-resistant bacterial infections.

Co-culturing with Streptococcus anginosus alters Staphylococcus aureus transcriptome when exposed to tonsillar cells.

Introduction: Improved understanding of Staphylococcus aureus throat colonization in the presence of other co-existing microbes is important for mapping S. aureus adaptation to the human throat, and recurrence of infection. Here, we explore the responses triggered by the encounter between two common throat bacteria, S. aureus and Streptococcus anginosus, to identify genes in S. aureus that are important for colonization in the presence of human tonsillar epithelial cells and S. anginosus, and further compare this transcriptome with the genes expressed in S. aureus as only bacterium. Methods: We performed an in vitro co-culture experiment followed by RNA sequencing to identify interaction-induced transcriptional alterations and differentially expressed genes (DEGs), followed by gene enrichment analysis. Results and discussion: A total of 332 and 279 significantly differentially expressed genes with p-value < 0.05 and log2 FoldChange (log2FC) ≥ |2| were identified in S. aureus after 1 h and 3 h co-culturing, respectively. Alterations in expression of various S. aureus survival factors were observed when co-cultured with S. anginosus and tonsillar cells. The serine-aspartate repeat-containing protein D (sdrD) involved in adhesion, was for example highly upregulated in S. aureus during co-culturing with S. anginosus compared to S. aureus grown in the absence of S. anginosus, especially at 3 h. Several virulence genes encoding secreted proteins were also highly upregulated only when S. aureus was co-cultured with S. anginosus and tonsillar cells, and iron does not appear to be a limiting factor in this environment. These findings may be useful for the development of interventions against S. aureus throat colonization and could be further investigated to decipher the roles of the identified genes in the host immune response in context of a throat commensal landscape.

Proton pump inhibitors alter gut microbiota by promoting oral microbiota translocation: a prospective interventional study.

BACKGROUND: The mechanism by which proton pump inhibitors (PPIs) alter gut microbiota remains to be elucidated. We aimed to learn whether PPI induced gut microbiota alterations by promoting oral microbial translocation. METHODS: Healthy adult volunteers were randomly assigned: PP group (n=8, 40 mg esomeprazole daily for seven days) and PM group (n=8, 40 mg esomeprazole along with chlorhexidine mouthwash after each meal for seven days). Fecal and saliva samples were analysed using 16S ribosomal RNA sequencing. Mouse models were introduced to confirm the findings in vivo, while the effect of pH on oral bacteria proliferation activity was investigated in vitro. RESULTS: Taxon-based analysis indicated that PPI administration increased Streptococcus abundance in gut microbiota (P<0.001), and the increased species of Streptococcus were found to be from the oral site or oral/nasal sites, in which Streptococcus anginosus was identified as the significantly changed species (P<0.004). Microbial source tracker revealed that PPI significantly increased the contribution of oral bacteria to gut microbiota (P=0.026), and no significant difference was found in PM group (P=0.467). Compared to the baseline, there was a 42-fold increase in gut abundance of Streptococcus anginosus in PP group (P=0.002), and the times decreased to 16-fold in PM group (P=0.029). Mouse models showed that combination of PPI and Streptococcus anginosus significantly increased the gut abundance of Streptococcus anginosus compared with using PPI or Streptococcus anginosus only. Furthermore, Streptococcus anginosus cannot survive in vitro at a pH lower than 5. CONCLUSIONS: PPIs altered gut microbiota by promoting oral-originated Streptococcus translocation into gut.

Streptococcus anginosus promotes gastric inflammation, atrophy, and tumorigenesis in mice.

Streptococcus anginosus (S. anginosus) was enriched in the gastric mucosa of patients with gastric cancer (GC). Here, we show that S. anginosus colonized the mouse stomach and induced acute gastritis. S. anginosus infection spontaneously induced progressive chronic gastritis, parietal cell atrophy, mucinous metaplasia, and dysplasia in conventional mice, and the findings were confirmed in germ-free mice. In addition, S. anginosus accelerated GC progression in carcinogen-induced gastric tumorigenesis and YTN16 GC cell allografts. Consistently, S. anginosus disrupted gastric barrier function, promoted cell proliferation, and inhibited apoptosis. Mechanistically, we identified an S. anginosus surface protein, TMPC, that interacts with Annexin A2 (ANXA2) receptor on gastric epithelial cells. Interaction of TMPC with ANXA2 mediated attachment and colonization of S. anginosus and induced mitogen-activated protein kinase (MAPK) activation. ANXA2 knockout abrogated the induction of MAPK by S. anginosus. Thus, this study reveals S. anginosus as a pathogen that promotes gastric tumorigenesis via direct interactions with gastric epithelial cells in the TMPC-ANXA2-MAPK axis.

Oral streptococci S. anginosus and S. mitis induce distinct morphological, inflammatory, and metabolic signatures in macrophages.

Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis, periodontal disease, and oral cancer. Specifically, Streptococcus anginosus is associated with esophageal, gastric, and pharyngeal cancers, while Streptococcus mitis is linked to oral cancer. However, no study has investigated the mechanistic links between these Streptococcus species and cancer-related inflammatory responses. As an initial step, we probed the innate immune response triggered by S. anginosus and S. mitis in RAW264.7 macrophages. These bacteria exerted time- and dose-dependent effects on macrophage morphology without affecting cell viability. Compared with untreated macrophages, macrophages infected with S. anginosus exhibited a robust proinflammatory response characterized by significantly increased levels of inflammatory cytokines and mediators, including TNF, IL-6, IL-1ß, NOS2, and COX2, accompanied by enhanced NF-κB activation. In contrast, S. mitis-infected macrophages failed to elicit a robust inflammatory response. Seahorse Xfe96 analysis revealed an increased extracellular acidification rate in macrophages infected with S. anginosus compared with S. mitis. At the 24-h time point, the presence of S. anginosus led to reduced extracellular itaconate, while S. mitis triggered increased itaconate levels, highlighting distinct metabolic profiles in macrophages during infection in contrast to aconitate decarboxylase expression observed at the 6-h time point. This initial investigation highlights how S. anginosus and S. mitis, two Gram-positive bacteria from the same genus, can prompt distinct immune responses and metabolic shifts in macrophages during infection.IMPORTANCEThe surge in head and neck cancer cases among individuals devoid of typical risk factors such as Human Papilloma Virus (HPV) infection and tobacco and alcohol use sparks an argumentative discussion around the emerging role of oral microbiota as a novel risk factor in oral squamous cell carcinoma (OSCC). While substantial research has dissected the gut microbiome's influence on physiology, the oral microbiome, notably oral streptococci, has been underappreciated during mucosal immunopathogenesis. Streptococcus anginosus, a viridans streptococci group, has been linked to abscess formation and an elevated presence in esophageal cancer and OSCC. The current study aims to probe the innate immune response to S. anginosus compared with the early colonizer Streptococcus mitis as an important first step toward understanding the impact of distinct oral Streptococcus species on the host immune response, which is an understudied determinant of OSCC development and progression.

ENDOGENOUS ENDOPHTHALMITIS DUE TO STREPTOCOCCUS ANGINOSUS IN A HEALTHY, YOUNG WOMAN.

PURPOSE: The purpose of this study was to present a case of indolent endogenous endophthalmitis in a young, seemingly healthy woman. METHODS: This study is a retrospective case report. RESULTS: A 25-year-old woman with no significant medical history presented with vision loss in the left eye over the course of 1 month. Examination showed vitritis and a white-yellow lesion overlying the macula and optic nerve in the left eye. Initial laboratory testing for infectious and inflammatory causes was unrevealing. A diagnostic vitrectomy was performed, and the patient was found to have presumed endogenous endophthalmitis due to Streptococcus anginosus, an extremely uncommon bacterium. Subsequent workup did not reveal evidence of bacteremia, endocarditis, or orbital infection. This case is unique because, unlike the three previously reported cases of S. anginosus endophthalmitis, this patient was seemingly healthy, never had an elevated white blood cell count, never had documented bacteremia, had a normal echocardiogram, and had normal orbital findings on magnetic resonance imaging and computed tomography scans. Further questioning revealed a remote history of facial cellulitis and possible sinusitis treated with oral antibiotics, which are the presumed etiology. CONCLUSION: Streptococcus anginosus endophthalmitis can occur in young, seemingly healthy patients. Endogenous endophthalmitis should be considered in the differential diagnosis even without systemic comorbidities or other risk factors. Detailed questioning about medical history and thorough review of systems, including nonocular symptoms, are essential.

Pertinence of Streptococcus anginosus group in intracerebral abscesses in the era of extended antibiotic resistance.

AIMS: • To study the incidence of Streptococcus anginosus group (SAG) in pyogenic or community acquired intra cerebral abscess. • To understand the risk factors for the same. • To analyze the specific radiological features and clinical outcome after surgery and antibiotic therapy. METHODS: This is a retrospective observational study of case series over a period of one year. Patients diagnosed with intracerebral abscess were included in the study. Pus collected from were received in the laboratory and processed according to the standard protocols. Data regarding the clinical findings and demographics were collected from medical records. FINDINGS: A total of 202 samples were studied. 103 were found to be pyogenic. SAG were isolated from 21 samples (20.38%) and all the isolates were sensitive to Penicillin. Age of the patients ranged from 18months to 68years. Male preponderance was noted with male to female ratio of 4:1. Otogenic infections were the most common predisposing factors and focus of infection could not be ascertained in 5 patients. All patients were treated with surgical intervention and antibiotics (Vancomycin, Amikacin and Metronidazole) for 6 weeks and recovery was remarkable. One patient succumbed to the illness. CONCLUSION: SAG can be an aggressive pathogen with propensity for abscess formation. Chronic Suppurative Otitis Media (CSOM) is still a major cause of intracerebral abscess in developing country like India which is a benign and curable disease and should not be neglected. Injudicious use of antibiotics and negligence regarding the dose and duration of therapy from both patients and health care providers is the major cause for common infections to become more difficult to treat and succumbing to complications.

Studies of Streptococcus anginosus Virulence in Dictyostelium discoideum and Galleria mellonella Models.

For many years, Streptococcus anginosus has been considered a commensal colonizing the oral cavity, as well as the gastrointestinal and genitourinary tracts. However, recent epidemiological and clinical data designate this bacterium as an emerging opportunistic pathogen. Despite the reported pathogenicity of S. anginosus, the molecular mechanism underpinning its virulence is poorly described. Therefore, our goal was to develop and optimize efficient and simple infection models that can be applied to examine the virulence of S. anginosus and to study host-pathogen interactions. Using 23 S. anginosus isolates collected from different infections, including severe and superficial infections, as well as an attenuated strain devoid of CppA, we demonstrate for the first time that Dictyostelium discoideum is a suitable model for initial, fast, and large-scale screening of virulence. Furthermore, we found that another nonvertebrate animal model, Galleria mellonella, can be used to study the pathogenesis of S. anginosus infection, with an emphasis on the interactions between the pathogen and host innate immunity. Examining the profile of immune defense genes, including antimicrobial peptides, opsonins, regulators of nodulation, and inhibitors of proteases, by quantitative PCR (qPCR) we identified different immune response profiles depending on the S. anginosus strain. Using these models, we show that S. anginosus is resistant to the bactericidal activity of phagocytes, a phenomenon confirmed using human neutrophils. Notably, since we found that the data from these models corresponded to the clinical severity of infection, we propose their further application to studies of the virulence of S. anginosus.

A mixed infection involving Bacteroides denticanum, Lactobacillus salivarius, and Streptococcus anginosus as causative agents of abscess around a pharyngo-esophageal anastomosis and acute vertebral osteomyelitis: Identification by ribosomal RNA sequencing of bacterial isolates.

"Bacteroides denticanum" is an anaerobic, non-spore-forming, gram-negative bacterium with a rod morphology typical of canine, ovine, and macropod oral flora. There is only one report of bloodstream infection caused by "B. denticanum" from a dog bite in human. Here, we report a case with no history of animal contact who developed an abscess caused by "B. denticanum" around a pharyngo-esophageal anastomosis after undergoing balloon dilatation procedure for stenosis following laryngectomy. The patient was a 73-year-old man with laryngeal cancer, esophageal cancer, hyperuricemia, dyslipidemia, and hypertension with a 4-week history of cervical pain, sore throat, and fever. Computed tomography showed fluid collection on the posterior pharyngeal wall. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) identified Bacteroides pyogenes, Lactobacillus salivarius, and Streptococcus anginosus from abscess aspiration. 16S ribosomal RNA sequencing re-identified the Bacteroides species as "B. denticanum". T2-weighted magnetic resonance images showed a high signal intensity adjacent to the anterior vertebral body of C3-C7. The diagnosis was peripharyngeal esophageal anastomotic abscess and acute vertebral osteomyelitis caused by "B. denticanum", L. salivarius, and S. anginosus. The patient was treated with sulbactam ampicillin intravenously for 14 days and then switched to oral amoxicillin with clavulanic acid for 6 weeks. To our knowledge, this is the first report of a human infection caused by "B. denticanum" without a history of animal contact. Despite remarkable advancements facilitated by MALDI-TOF MS in microbiological diagnosis, the accurate identification of novel, emerging, or uncommon microorganisms and comprehending their pathogenicity, suitable therapy, and follow up necessitate sophisticated molecular approaches.

Comparative Genomic Study of Streptococcus anginosus Reveals Distinct Group of Urinary Strains.

Streptococcus anginosus is a prevalent member of the human flora. While it has been found in the microbiota of "healthy" asymptomatic individuals, it has also been associated with genitourinary tract infections and bacteremia. Based upon multilocus sequence analysis, two subspecies and two genomosubspecies have been characterized for the species. We previously conducted whole-genome sequencing of 85 S. anginosus isolates from the urinary tract. Here, we present genomic analysis of this species, including isolates from the urinary tract as well as gut and fecal, vaginal, oral, respiratory, and blood and heart samples. Average nucleotide identity and core genome analysis revealed that these strains form two distinct groups. Group 1 is comprised of the S. anginosus type strain and other previously identified S. anginosus subspecies and genomosubspecies, including isolates from throughout the human body. In contrast, group 2 consists of predominantly urinary streptococci (n = 77; 85.6%). Both of these S. anginosus groups are distinct from other members of the Streptococcus anginosus group (SAG) species S. intermedius and S. constellatus. Genes conserved among all strains of one group but not in any strains in the other group were next identified. Group 1 strains included genes found in S. intermedius and S. constellatus, suggesting that they were lost within the ancestor of the group 2 strains. In contrast, genes unique to the group 2 strains were homologous to more distant streptococci, indicative of acquisition via horizontal gene transfer. These genes are ideal candidates for use as marker genes to distinguish between the two groups in the human microbiota. IMPORTANCE Whole-genome analysis of S. anginosus strains provides greater insight into the diversity of this species than from marker genes alone. Our investigation of 166 publicly available S. anginosus genomes via average nucleotide identity and core genome analysis revealed two phylogenomically distinct groups of this species, with one group almost exclusively consisting of isolates from the urinary tract. In contrast, only 8 urinary strains were identified within the other group, which contained the S. anginosus type strain, as well as all identified subspecies and genomosubspecies. While genomic analysis suggested that this urinary group of S. anginosus is genomically different from the previously characterized S. anginosus subspecies, phenotypic characterization is still needed. Given prior reports of the prevalence of S. anginosus in the urinary tract of both continent and incontinent females, future studies are needed to investigate if the symptom state of the urinary tract is associated with these two different groups.

Streptococcus anginosus: a stealthy villain in deep odontogenic abscesses.

Odontogenic infections (OIs) occasionally spread to deep facial and neck tissues. Our study aimed to explore the role of Streptococcus anginous group (SAG) in these severe OIs. A retrospective study of patients aged ≥ 18 years who required hospital care for acute OI was conducted. We analysed data of OI microbial samples and recorded findings of SAG and other pathogens. These findings were compared with data regarding patients' prehospital status and variables of infection severity. In total, 290 patients were included in the analyses. The most common (49%) bacterial finding was SAG. Other common findings were Streptococcus viridans and Prevotella species, Parvimonas micra, and Fusobacterium nucleatum. Infection severity variables were strongly associated with SAG occurrence. Treatment in an intensive care unit was significantly more common in patients with SAG than in patients without SAG (p < 0.001). In addition, SAG patients expressed higher levels of C-reactive protein (p = 0.001) and white blood cell counts (p < 0.001), and their hospital stays were longer than those of non-SAG patients (p = 0.001). SAG is a typical finding in severe OIs. Clinical features of SAG-related OIs are more challenging than in other OIs. Early detection of SAG, followed by comprehensive infection care with prompt and careful surgical treatment, is necessary due to the aggressive behaviour of this dangerous pathogen.

A rare paediatric case of possible infective endocarditis caused by Streptococcus anginosus.

Infective endocarditis in children is a rare but serious condition that requires prompt management. We present a case of an 11-year-old boy with subacute bacterial endocarditis caused by Streptococcus anginosus, an unusual causative microorganism for infective endocarditis. The patient presented with a history of malaise, fatigue, and one subjective tactile fever. To the best of our knowledge, this is the first paediatric case of possible infective endocarditis caused by Streptococcus anginosus.

Holospinal epidural abscess caused by Streptococcus anginosus group: a literature review.

Spinal epidural abscess (SEA) usually extends over three to four vertebrae. We present a case of holospinal epidural abscess (HEA) caused by the Streptococcus anginosus group (SAG). A man in his 40s with a 2-week history of fever, back pain, and progressive tetraparesis was referred to us from the local hospital. MRI showed epidural fluid collection from C2 to S1. Blood and pus cultures revealed the presence of SAG. He was treated by emergency laminoplasty, epidural drainage and antibiotic treatment. After the 111st hospital day, his manual muscle test was shown to improve; hence, he was transferred for rehabilitation. According to the previous reports, we identified 12 cases of SEA extending from the cervical spine to the sacrum, including our case. For one-fourth of these cases, SAG was the causative organism of this rare SEA. Therefore, SAG should be considered causative organisms in HEA.

Clinical Microbial Identification of Severe Oral Infections by MALDI-TOF Mass Spectrometry in Stockholm County: an 11-Year (2010 to 2020) Epidemiological Investigation.

Growing evidence suggests that oral infections can modify the course of systemic diseases. To date, epidemiological data on microbial oral infections are scarce. Here, we performed a comprehensive analysis of the trend and microbial diversity in oral infection specimens referred for clinical microbiology analysis from 2010 to 2020. The microbes were isolated by culture and were identified via matrix-assisted laser desorption ionization-time of flight mass spectrometry technology (MALDI-TOF MS) throughout the study period. A total of 1,014 referred samples from dental clinics in Stockholm County with dentoalveolar abscesses and jaw osteomyelitis being the main reason were identified. Overall, the microbial composition was dominated by Firmicutes (51%), followed by Bacteroidetes (19%), Proteobacteria (12%), and Actinobacteria (5%). At the genus level, Streptococcus spp. (36%), Prevotella spp. (18%), and Staphylococcus spp. (11%) were among the most frequently reported. Interestingly, a strong increase in trend was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, Actinomyces spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, and Granulicatella adiacens during the study time (R = 0.66 to 0.89, P < 0.05), and a minor increase was noted for Enterococcus faecalis and Klebsiella spp., whereas steady levels were noted for most of the others. The present study shows the diversity of bacteria that have been involved in dental infections during the last decade in the capital of Sweden, as well as the emerging oral microbiota trend, with clear clinical implications on the oral-systemic link. IMPORTANCE Oral diseases and associated microbes are a risk factor for systemic diseases and can change the courses of these diseases. To date, epidemiological data on microbial oral infections are scarce, and longitudinal reports are lacking. We present for the first time the microbial composition of severe oral bacterial infections determined via the MALDI-TOF mass spectrometry technique in a comprehensive study between 2010 and 2020 (11 years) in Stockholm County. The trend and microbial diversity of oral infections were analyzed on referred clinical microbiological samples and were processed by standardized protocols. Trend increase was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, Actinomyces spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, Granulicatella adiacens, Enterococcus faecalis, and Klebsiella spp. Our results provide new insights into the diversity and trend of oral microbiota that were involved in serious oral infections over the past decade in the capital of Sweden and may influence the oral-systemic link.

Laboratory Diagnosis, Antimicrobial Susceptibility And Genuine Clinical Spectrum of Streptococcus anginosus Group; Our Experience At A University Hospital.

Background: Streptococcus anginosus group (SAG) may be unrecognized or misidentified in the Clinical Microbiology Laboratory resulting in under-reporting. Consequently, their role as genuine pathogens remains underestimated. Objectives: The aim of this study is to suggest a reasonable identification approach that is suitable for laboratories of limited resources, to detect any possible emerging antimicrobial resistance, and to assess the genuine clinical spectrum of infections that are caused solely by SAG. Methods: Our research included 190 bacterial isolates from 190 patients. The isolates were examined by colonies' morphology, odor, hemolytic pattern on 5% sheep Blood agar and Gram staining. Lancefield serogrouping was determined by agglutination test. Antimicrobial susceptibility testing (AST) was performed by disc diffusion method. The isolates were subjected to automated identification and AST by Vitek 2 compact instrument. The collected patients' data included age, gender, clinical condition and/or site of infection, and probable predisposing factor. Results: All isolates produced minute-sized colonies that consistently generated distinct odor. The isolates showed variable hemolytic patterns, and the majority (74.7%) were non-hemolytic. The isolates showed different Lancefield serogroups, and the commonest was group F (54.2%). A total of 188 (98.9%) isolates were identified by Vitek 2 compact instrument at ≥95% confidence. The isolates showed high rates of antimicrobial susceptibility, however the highest rate of antimicrobial resistance was detected to gentamicin (60.5%). A total of 98 (51.6%) strains were isolated from superficial non-invasive skin and soft tissue infections, 67 (35.3%) strains from deep invasive and sterile body fluids' infections, and 25 (13.1%) strains from upper respiratory tracts' infections. Conclusion: a combination of phenotypic characteristics could still represent a reasonable Laboratory identification battery. There was no significant emerging antimicrobial resistance detected. A broad genuine spectrum of clinical infections that are caused solely by SAG was reported in our institution.