Streptococcus anginosus ("Streptococcus milleri"): the unrecognized pathogen

Brain Abscess Caused by Oral Cavity Bacteria: A Nationwide, Population-based Cohort Study

BACKGROUND

Oral cavity bacteria are the most frequent etiology of brain abscess. Yet, data on the clinical presentation and outcome are scarce.

METHODS

We performed a nationwide, population-based study comprising all adults (aged ≥18 years) with brain abscess due to oral cavity bacteria in Denmark from 2007 through 2020. Prognostic factors for unfavorable outcome (Glasgow outcome scale, 1-4) were examined using modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Among 287 identified patients, the median age was 58 years (interquartile range, 47-66), and 96 of 287 (33%) were female. Preexisting functional impairment was absent or mild in 253 of 280 (90%), and risk factors for brain abscess included immunocompromise in 95 of 287 (33%), dental infection in 68 of 287 (24%), and ear-nose-throat infection in 33 of 287 (12%). Overall, a neurological deficit was present in 246 of 276 (86%) and in combination with headache and fever in 64 of 287 (22%). Identified microorganisms were primarily the Streptococcus anginosus group, Fusobacterium, Actinomyces, and Aggregatibacter spp., and 117 of 287 (41%) were polymicrobial. Unfavorable outcome occurred in 92 of 246 (37%) at 6 months after discharge and was associated with antibiotics before neurosurgery (RR, 3.28; 95% CI, 1.53-7.04), rupture (RR, 1.89; 95% CI, 1.34-2.65), and immunocompromise (RR, 1.80; 95% CI, 1.29-2.51), but not with specific targeted antibiotic regimens. Identified dental infection was associated with favorable prognosis (RR, 0.58; 95% CI, .36-.93).

CONCLUSIONS

Brain abscess due to oral cavity bacteria often occurred in previously healthy individuals without predisposing dental infections. Important risk factors for unfavorable outcome were rupture and immunocompromise. However, outcome was not associated with specific antibiotic regimens supporting carbapenem-sparing strategies.

Use of Biomaterials in 3D Printing as a Solution to Microbial Infections in Arthroplasty and Osseous Reconstruction

The incidence of microbial infections in orthopedic prosthetic surgeries is a perennial problem that increases morbidity and mortality, representing one of the major complications of such medical interventions. The emergence of novel technologies, especially 3D printing, represents a promising avenue of development for reducing the risk of such eventualities. There are already a host of biomaterials, suitable for 3D printing, that are being tested for antimicrobial properties when they are coated with bioactive compounds, such as antibiotics, or combined with hydrogels with antimicrobial and antioxidant properties, such as chitosan and metal nanoparticles, among others. The materials discussed in the context of this paper comprise beta-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP), hydroxyapatite, lithium disilicate glass, polyetheretherketone (PEEK), poly(propylene fumarate) (PPF), poly(trimethylene carbonate) (PTMC), and zirconia. While the recent research results are promising, further development is required to address the increasing antibiotic resistance exhibited by several common pathogens, the potential for fungal infections, and the potential toxicity of some metal nanoparticles. Other solutions, like the incorporation of phytochemicals, should also be explored. Incorporating artificial intelligence (AI) in the development of certain orthopedic implants and the potential use of AI against bacterial infections might represent viable solutions to these problems. Finally, there are some legal considerations associated with the use of biomaterials and the widespread use of 3D printing, which must be taken into account.

Long-term follow-up of a healthy man with endogenous Streptococcus anginosus endophthalmitis

We report the long-term follow-up of an immunocompetent patient who presented with slowly progressive endogenous endophthalmitis secondary to Streptococcus anginosus. A 46-year-old healthy man presented with a two-month history of right eye iritis. On examination, visual acuity was 20/60 with intraocular pressure of 6 mm Hg. There was a small layer of hypopyon with non-granulomatous anterior uveitis and vitritis. On funduscopy, fluffy white peripheral retinal and pre-retinal lesions were noted in superonasal periphery. The patient denied any present or past illness. Diagnostic pars plana vitrectomy was performed. Culture and polymerase chain reaction of the vitreous sample were positive for Streptococcus anginosus. Intravitreal vancomycin and ceftazidime and systemic ceftriaxone were administered. Work-up which included blood and urine cultures, chest x-ray, echocardiography and abdominal ultrasound was unyielding. Subsequently and because of persistent post-infectious inflammatory reaction, intravitreal and oral steroids were administered in addition to oral azathioprine later on. After one year of follow-up, visual acuity was 20/20 with near vision of Jaeger 3 + and no signs of active uveitis were seen. Therefore, Streptococcus anginosus should be considered in the differential diagnosis of a slowly progressive endophthalmitis also in immunocompetent individuals.

Bacteremia from streptococcus constellatus revealing a gastrointestinal stromal tumor

BACKGROUND

Pyogenic Liver Abscesses (PLA) are the most common type of visceral abscess. They generally develop in a context of biliary disease or hematogenous seeding, but a complete diagnostic work-up is always required in order not to miss other important causes, including above all malignancies of the gastro-intestinal tract.

CASE PRESENTATION

Herein, we report a particular case of a 80 years-old immunocompetent woman hospitalized for sepsis. At the end of the diagnostic process, Streptococcus constellatus (Sc) was identified as the cause of sepsis, multiple PLA were found together with a previous unknown ileal malignancy. We speculated about a possible correlation among these three entities (i.e. sepsis from Sc, PLA and tumors).

CONCLUSIONS

Detection of Sc in blood should raise red flags in clinicians as aggressive clinical presentation are possible.

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.

Upper respiratory tract microbiota is associated with small airway function and asthma severity

BACKGROUND

Characteristics of airway microbiota might influence asthma status or asthma phenotype. Identifying the airway microbiome can help to investigate its role in the development of asthma phenotypes or small airway function.

METHODS

Bacterial microbiota profiles were analyzed in induced sputum from 31 asthma patients and 12 healthy individuals from Beijing, China. Associations between small airway function and airway microbiomes were examined.

RESULTS

Composition of sputum microbiota significantly changed with small airway function in asthma patients. Two microbiome-driven clusters were identified and characterized by small airway function and taxa that had linear relationship with small airway functions were identified.

CONCLUSIONS

Our findings confirm that airway microbiota was associated with small airway function in asthma patients.

Focal Neurological Symptoms at Initial Presentation Could Be a Potential Risk Factor for Poor Prognosis Among Patients With Multiple Brain Abscesses by Streptococcus anginosus Group: A Case Report With Literature Review

Streptococcus anginosus group (SAG) is one of the most common microbes of brain abscesses. Brain abscesses caused by SAG have often delayed diagnosis since both blood and cerebrospinal fluid cultures are negative in half of the cases. A 68-year-old man developed persistent fever, headache, and myalgias for two weeks and visited our department. He was treated with oral antibiotics without laboratory work. Although examination showed no focal neurological symptoms, a careful interview revealed a history of unusual behavior for a few minutes on the previous day. Whole body contrast-enhanced computed tomography (CT) and head magnetic resonance imaging (MRI) showed two ring enhancements close to the bilateral ventricles, which were consistent with a diagnosis of the brain abscesses. An emergent surgical puncture for the larger abscess with intravenous antimicrobial therapy quickly improved his condition, and he was discharged on day 36 with no sequelae. We retrospectively reviewed works of literature on cases with multiple brain abscesses by SAG to assess potential prognostic factors for neurological sequelae. Statistical analyses of 12 cases, including 11 cases from the literature review and the current case, were performed between groups with or without poor prognosis. Among potential risk factors of age, sex, focal neurological symptoms, duration from onset to treatment, abscess formation of other organs, presence of surgical drainage, and positive for blood culture, only focal neurological symptoms at the initial presentation were significantly associated with poor prognosis (no poor prognosis, 1/4 cases vs poor prognosis group, 8/8 cases; p=0.01). Careful interviews and detailed examinations should be conducted to assess the possibility of brain abscesses among patients with fever of unknown etiology. Otherwise, a delayed diagnosis might result in poor prognoses such as death or neurological sequelae due to this disease's nature, which has few specific symptoms in the early stages.

Recurrent Paravaginal Abscess: An Unusual Presentation of a Distal Ectopic Ureteral Remnant

Introduction

Obstructed hemivagina ipsilateral renal agenesis (OHVIRA) is a rare syndrome with limited data on both treatment and postoperative sequelae, specifically of ectopic ureters to the vagina.

Case Description

This case study describes a 22-year-old patient with OHVIRA syndrome presenting with pelvic pain and drainage from a chronic vaginal abscess secondary to a remnant distal ectopic ureter after nephrectomy and proximal ureterectomy. Imaging was significant for a right paravaginal abscess. Previously, the patient was treated with conservative therapy and on presentation her evaluation confirmed a right paravaginal abscess. She subsequently underwent a robot-assisted incision and drainage of the paravaginal abscess and excision of the remnant distal ectopic ureter. She did well postoperatively without recurrence.

Discussion

We discuss the successful surgical technique used to identify and excise a paravaginal abscess. We also highlight the unique anatomy of a patient with OHVIRA syndrome. Lastly, we underline the importance of a complete resection of an ectopic ureter to the vagina at the time of nephrectomy, given the potential risk of ascending chronic infection and recurrent abscess formation.

Changes in the Management of Severe Orbital Infections Over Seventeen Years

OBJECTIVES

Periorbital and orbital cellulitis are common but serious infections in children. Management of these infections varies because of an absence of clinical guidelines, but it is unclear if management within institutions has changed over time. We compared the management and outcomes of children hospitalized with periorbital and orbital cellulitis in 2 eras.

METHODS

Data were extracted from records of children hospitalized at a tertiary care children's hospital with periorbital or orbital cellulitis from 2000 to 2005 and 2012 to 2016. Patient demographics, cross-sectional imaging, antibiotic and corticosteroid use, length of stay, and surgical rates were collected. Data from the eras were compared by using descriptive statistics, t tests, Mann-Whitney U tests, Fisher's exact tests, and χ² tests.

RESULTS

There were 318 children included, 143 from 2000 to 2005 and 175 from 2012 to 2016. Compared with the first era, in the second era there were increased rates of MRI (5% vs 11%, P = .04), although rates of computed tomography scan use remained unchanged (60% vs 65%); increased number (1 vs 3, P < .01) and spectrum of antibiotics; increased use of intranasal corticosteroids (3% vs 49%, P < .01); and subspecialty consultation (89% vs 99%, P = .01). There were no differences in length of stay, readmission, or surgical rates between eras.

CONCLUSIONS

There has been considerable change in the management of hospitalized children with severe orbital infections at our institution, including the rates of MRI, number and spectrum of antibiotics used, use of adjunctive agents, and increased subspecialty involvement with no observed impact on clinical outcomes. Future research is needed to rationalize antimicrobial therapy and reduce low-value health care.

Suppurative Intracranial Complications of Pediatric Sinusitis: A Single-Center Experience

BACKGROUND

Suppurative intracranial complications of sinusitis are rare events in children and can lead to harmful neurologic sequelae and significant morbidity. We sought to review the presentation and management of patients admitted at our hospital with these conditions.

METHODS

This was a retrospective study of pediatric patients admitted to a quaternary children's hospital from 2007 to 2019 for operative management of sinusitis with intracranial extension. Clinical characteristics, including surgical and microbiological data, were collected and analyzed.

RESULTS

Fifty-four patients were included; the median age was 11.0 years, and there was a male predominance. Eighty-nine percent of patients had prior healthcare visits for the current episode of sinusitis; 46% of patients had an abnormal neurologic exam on admission. Epidural abscess and subdural empyema were the most common complications, and subdural empyema was associated with repeat surgical intervention. The dominant pathogens were Streptococcus anginosus group organisms (74%). The majority of patients completed treatment parenterally, with a median duration of therapy of 35 days. Neurological sequelae, including epilepsy or ongoing focal deficits, occurred in 22% of patients. History of seizure or an abnormal neurological exam at admission were associated with neurological sequelae.

CONCLUSIONS

Clinicians should consider intracranial complications of sinusitis in patients with symptoms of sinusitis for >1 week. Patients should undergo urgent neuroimaging, as neurosurgical intervention is essential for these patients. Subdural empyema was associated with repeat neurosurgical intervention. Neurological sequelae occurred in 22% of patients, and new onset seizure or an abnormal neurological exam at admission were associated with neurological sequelae.

Successful laparoscopic management of a hepatic abscess caused by a fish bone

BACKGROUND

Hepatic abscess is a rare condition but comes with heavy consequences if not diagnosed and managed properly. Early detection of this pathology is challenging because of the variety and lack of specificity of symptoms but is necessary for accurate management.

CASE REPORT

We report a case of pyogenic liver abscess secondary to the migration of an ingested fish bone in a 74-year-old female. We used laparoscopic surgery to drain the abscess, remove the foreign body responsible and look for the perforation site. Parenteral antibiotherapy was added to the surgical treatment.

CONCLUSION

Early diagnosis of hepatic abscess caused by the migration of a foreign body remains a challenge. In our opinion, laparoscopic surgery associated with antibiotics is the safest and most effective therapeutic option.

A successfully treated case of primary purulent pericarditis complicated by cardiac tamponade and pneumopericardium

Acute pericarditis is caused by various factors, but purulent pericarditis is rare. Primary purulent pericarditis in immunocompetent hosts is very rare in the modern antibiotics era. We report a successfully treated case of primary purulent pericarditis complicated with cardiac tamponade and pneumopericardium in an immunocompetent host. A 69-year-old female was referred from another hospital because of pleuritic chest pain with a large amount of pericardial effusion. She was diagnosed with acute pericarditis accompanied by cardiac tamponade. We performed emergency pericardiocentesis, with drainage of 360 ml of bloody pericardial fluid. The culture grew Streptococcus anginosus, confirming the diagnosis of acute purulent pericarditis. We performed pericardiostomy because cardiomegaly and pneumopericardium were aggravated after removal of the pericardial drainage catheter. The patient received antibiotics for a total of 23 days intravenously and was discharged with oral antibiotic therapy. Purulent pericarditis is one of the rare forms of pericarditis and is life-threatening. A multimodality approach is required for proper diagnosis and treatment of this disease.

Comparative study on the microbial quality in the swimming pools disinfected by the ozone-chlorine and chlorine processes in Tabriz, Iran

Applying a desirable disinfestation process is necessary to control the pathogenic microorganisms in the swimming pools and prevent both dermal and intestinal effects. Therefore, the present study was conducted to compare the bacterial community and diversity in the two swimming pools disinfected by the chlorine and ozone (O₃)-chlorine processes. A total of 24 samples were taken from the two swimming pools in three distinct seasons to analyze the bacterial and physico-chemical indicators. Culture and molecular methods were used to evaluate the microbial quality. Two sets of sample taken from the pools with the maximum swimmer load in the summer were investigated by the next-generation sequencing (NGS) technique. In total, 410 and 406 bacterial species were identified in the chlorine- and ozone-chlorine-disinfected pools, respectively. Among the eight dominant bacterial species in each swimming pool, Pseudomonas alcaliphila, Pseudomonas stutzeri, and Pseudomonas acnes were common species between the two studied pools. Oleomonas sagaranensis (350 reads/18593), Staphylococcus caprae (302 reads /18593), and Anaerococcus octavius (110 reads/18593) were among the dominant bacteria in the chlorine-disinfected pool. Bacterial diversity was lower in the ozone-chlorine-disinfected pool than the other one, and the highest bacterial sequencing belonged to the genus Pseudomonas (85.79%). Results showed that water quality of in O₃-chlorine-disinfected pool was more desirable than the chlorine-disinfected pool. Molecular methods along with conventional culture methods would be advantageous for microbial assessment in the swimming pools.

Characterization and spontaneous induction of urinary tract Streptococcus anginosus prophages

Streptococcus anginosus is an often overlooked and understudied emerging pathogen inhabiting many areas of the human body. Through our sequencing of S. anginosus strains isolated from the female bladder microbiota, we detected numerous prophage sequences. Bioinformatic analysis of these sequences identified 17 distinct groups of S. anginosus prophages. The majority of these phages exhibit no sequence homology to previously characterized temperate or virulent phage sequences, indicating an unexplored diversity of Streptococcus phages. By culturing these bacterial isolates, we confirmed that the prophages of five of these groups are capable of induction. One of these putative phages was imaged, the first such evidence of an S. anginosus virus-like particle; it exhibits morphological characteristics of siphoviruses.

Treatment of pediatric extra-axial sinogenic infection: case series and literature review

PURPOSE

Analyze the clinical presentation, microbiology, outcomes, and medical and surgical treatment strategies of intracranial extension of sinogenic infection in pediatric patients.

METHODS

A retrospective, single-center study of patients < 18 years of age, presenting with intracranial extension of bacterial sinogenic infections requiring surgical intervention over a 5-year period, was conducted. Electronic medical records were reviewed for age, sex, primary symptoms, duration of symptoms, presence of sinusitis at initial presentation, microorganisms isolated, mode of surgery, timing of surgery, length of stay, and neurologic sequelae.

RESULTS

Seventeen patients were identified; mean age was 10 years with 82.3% male predominance. Average duration of illness prior to presentation was 9.8 days, with 64.7% of patients displaying disease progression while on oral antibiotics prior to presentation. Sinusitis and intracranial extension were present in all patients upon admission. Simultaneous endoscopic endonasal drainage and craniotomy were performed on 70.5% of the patients, with the remaining 29.5% undergoing endonasal drainage only. Of the patients who underwent simultaneous endoscopic endonasal drainage and craniotomy, 17.6% required repeat craniotomy and 5.8% required repeat sinus surgery. The most commonly isolated organisms were S. intermedius (52.9%), S. anginosus (23.5%), and S. pyogenes (17.6%). All patients were treated postoperatively antibiotic on average 4-6 weeks. Frequently occurring long-lasting complications included seizures (29.4%) and focal motor deficits (17.6%); learning disability, anxiety disorders, impaired cognition, and sensory deficits occurred less frequently.

CONCLUSION

In the case of intracranial extension of bacterial sinogenic infection, early identification and surgical treatment are crucial to avoid neurological sequelae.

Microbial aetiology of brain abscess in a UK cohort: Prominent role of Streptococcus intermedius

BACKGROUND

Brain abscess is an uncommon condition, but carries high mortality. Current treatment guidelines are based on limited data. Surveillance of clinical, radiological and microbiology data is important to inform patient stratification, interventions, and antimicrobial stewardship.

METHODS

We undertook a retrospective, observational study of patients with brain abscess, based on hospital coding, in a UK tertiary referral teaching hospital. We reviewed imaging data, laboratory microbiology, and antibiotic prescriptions.

RESULTS

Over a 47 month period, we identified 47 adults with bacterial brain abscess (77% male, median age 47 years). Most of the abscesses were solitary frontal or parietal lesions. A microbiological diagnosis was secured in 39/47 (83%) of cases, among which the majority were of the Streptococcus milleri group (27/39; 69%), with a predominance of Streptococcus intermedius (19/27; 70%). Patients received a median of 6 weeks of intravenous antibiotics (most commonly ceftriaxone), with variable oral follow-on regimens. Ten patients (21%) died, up to 146 days after diagnosis. Mortality was significantly associated with increasing age, multiple abscesses, immunosuppression and the presence of an underlying cardiac anomaly.

CONCLUSION

Our data suggest that there has been a shift away from staphylococcal brain abscesses, towards S. intermedius as a dominant pathogen. In our setting, empiric current first line therapy with ceftriaxone remains appropriate on microbiological grounds and narrower spectrum therapy may sometimes be justified. Mortality of this condition remains high among patients with comorbidity. Prospective studies are required to inform optimum dose, route and duration of antimicrobial therapy.

Eikenella Corrodens and Streptococcus anginosus co-infection causing skull base osteomyelitis and internal carotid artery lesion

A 35-year-old male presented with headaches and fevers. MRI of his head showed skull-based infection of the clivus extended to the right internal carotid artery. Blood and sinus cultures were positive for Eikenella corrodens and Streptococcus anginosus. He had intravenous antibiotics and sinus washout. The patient had full neurological recovery following this.

Acute Respiratory Distress Syndrome immediately following the removal of an aspirated foreign body

Acute Respiratory Distress Syndrome (ARDS) is a form of diffuse lung injury with many potential etiologies, pneumonia being the most common cause developing outside of the hospital. Foreign body (FB) aspiration is a risk factor for pneumonia, and therefore, ARDS. Although these associations exist, the development of ARDS immediately following the removal of an aspirated FB appears quite rare.

We present the case of an 11 year old male who was found to have a right-sided, post-obstructive pneumonia secondary to an aspirated FB obstructing the bronchus intermedius. Relief of the obstruction allowed for rapid, endobronchial spread of infection and within 6 hours of FB removal, our patient developed severe ARDS requiring initiation of extracorporeal membrane oxygenation (ECMO). Streptococcus constellatus was isolated from lower respiratory cultures obtained during initial bronchoscopy.

Pyogenic Liver Abscess Secondary to Sigmoid Diverticulitis: An Unusual Presentation

Pyogenic liver abscesses, despite being a rare complication of diverticulitis and inflammatory bowel disease, are potentially serious life-threatening pathologies. Diverticular diseases can lead to disruption of the colonic mucosal barrier and can serve as a route for bacterial infection via the portal venous system. This patient had such a delayed presentation due to his atypical symptoms; he developed large abscess formation, detected by computed tomography, eventually requiring an ultrasound-guided drain followed by a colonoscopy. The present report describes an elderly gentleman who developed a bacterial liver abscess due to seeding of a commensal organism caused by sigmoid diverticulitis.

Evidence that intra-amniotic infections are often the result of an ascending invasion - a molecular microbiological study

Background Microbial invasion of the amniotic cavity resulting in intra-amniotic infection is associated with obstetrical complications such as preterm labor with intact or ruptured membranes, cervical insufficiency, as well as clinical and histological chorioamnionitis. The most widely accepted pathway for intra-amniotic infection is the ascension of microorganisms from the lower genital tract. However, hematogenous dissemination of microorganisms from the oral cavity or intestine, retrograde seeding from the peritoneal cavity through the fallopian tubes, and introduction through invasive medical procedures have also been suggested as potential pathways for intra-amniotic infection. The primary reason that an ascending pathway is viewed as most common is that the microorganisms most often detected in the amniotic fluid are those that are typical inhabitants of the vagina. However, thus far, no studies have shown that microorganisms in the amniotic cavity are simultaneously present in the vagina of the woman from which they were isolated. The objective of the study was to determine the frequency with which microorganisms isolated from women with intra-amniotic infection are also present in the lower genital tract. Methods This was a cross-sectional study of women with intra-amniotic infection with intact membranes. Intra-amniotic infection was defined as a positive culture and elevated concentrations of interleukin-6 (IL-6) (>2.6 ng/mL) in amniotic fluid and/or acute histologic chorioamnionitis and funisitis. Microorganisms isolated from bacterial cultures of amniotic fluid were taxonomically identified through matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and 16S ribosomal RNA (rRNA) gene sequencing. Vaginal swabs were obtained at the time of amniocentesis for the identification of microorganisms in the lower genital tract. The overall bacterial profiles of amniotic fluids and vaginal swabs were characterized through 16S rRNA gene sequencing. The bacterial profiles of vaginal swabs were interrogated for the presence of bacteria cultured from amniotic fluid and for the presence of prominent (>1% average relative abundance) operational taxonomic units (OTUs) within the overall 16S rRNA gene bacterial profiles of amniotic fluid. Results (1) A total of 75% (6/8) of women had bacteria cultured from their amniotic fluid that are typical residents of the vaginal ecosystem. (2) A total of 62.5% (5/8) of women with bacteria cultured from their amniotic fluid also had these bacteria present in their vagina. (3) The microorganisms cultured from amniotic fluid and also detected in the vagina were Ureaplasma urealyticum, Escherichia coli, and Streptococcus agalactiae. (4) 16S rRNA gene sequencing revealed that the amniotic fluid of women with intra-amniotic infection had bacterial profiles dominated by Sneathia, Ureaplasma, Prevotella, Lactobacillus, Escherichia, Gardnerella, Peptostreptococcus, Peptoniphilus, and Streptococcus, many of which had not been cultured from the amniotic fluid samples. (5) Seventy percent (7/10) of the prominent (>1% average relative abundance) OTUs found in amniotic fluid were also prominent in the vagina. Conclusion The majority of women with intra-amniotic infection had bacteria cultured from their amniotic fluid that were typical vaginal commensals, and these bacteria were detected within the vagina at the time of amniocentesis. Molecular microbiological interrogation of amniotic fluid from women with intra-amniotic infection revealed that the bacterial profiles of amniotic fluid were largely consistent with those of the vagina. These findings indicate that ascension from the lower genital tract is the primary pathway for intra-amniotic infection.

Late deep cervical infection after anterior cervical discectomy and fusion: a case report and literature review

Background

Anterior cervical discectomy and fusion (ACDF) is often performed for the treatment of degenerative cervical spine. While this procedure is highly successful, 0.1–1.6% of early and late postoperative infection have been reported although the rate of late infection is very low.

Case presentation

Here, we report a case of 59-year-old male patient who developed deep cervical abscess 30 days after anterior cervical discectomy and titanium cage bone graft fusion (autologous bone) at C3/4 and C4/5. The patient did not have esophageal perforation. The abscess was managed through radical neck dissection approach with repated washing and removal of the titanium implant. Staphylococcus aureus was positively cultured from the abscess drainage, for which appropriate antibiotics including cefoxitin, vancomycin, levofloxacin, and cefoperazone were administered postoperatively. In addition, an external Hallo frame was used to support unstable cervical spine. The patient’s deep cervical infection was healed 3 months after debridement and antibiotic administration. His cervial spine was stablized 11 months after the surgery with support of external Hallo Frame.

Conclusions

This case suggested that deep cervical infection should be considered if a patient had history of ACDF even in the absence of esophageal perforation.

Pathogenicity Factors in Group C and G Streptococci

Initially recognized zoonoses, streptococci belonging to Lancefield group C (GCS) and G (GGS) were subsequently recognised as human pathogens causing a diverse range of symptoms, from asymptomatic carriage to life threatening diseases. Their taxonomy has changed during the last decade. Asymptomatic carriage is <4% amongst the human population and invasive infections are often in association with chronic diseases such as diabetes, cardiovascular diseases or chronic skin infections. Other clinical manifestations include acute pharyngitis, pneumonia, endocarditis, bacteraemia and toxic-shock syndrome. Post streptococcal sequalae such as rheumatic fever and acute glomerulonephritis have also been described but mainly in developed countries and amongst specific populations. Putative virulence determinants for these organisms include adhesins, toxins, and other factors that are essential for dissemination in human tissues and for interference with the host immune responses. High nucleotide similarities among virulence genes and their association with mobile genetic elements supports the hypothesis of extensive horizontal gene transfer events between the various pyogenic streptococcal species belonging to Lancefield groups A, C and G. A better understanding of the mechanisms of pathogenesis should be apparent by whole-genome sequencing, and this would result in more effective clinical strategies for the pyogenic group in general.

Regulation of the β-hemolysin gene cluster of Streptococcus anginosus by CcpA

Streptococcus anginosus is increasingly recognized as an opportunistic pathogen. However, our knowledge about virulence determinants in this species is scarce. One exception is the streptolysin-S (SLS) homologue responsible for the β-hemolytic phenotype of the S. anginosus type strain. In S. anginosus the expression of the hemolysin is reduced in the presence of high glucose concentrations. To investigate the genetic mechanism of the hemolysin repression we created an isogenic ccpA deletion strain. In contrast to the wild type strain, this mutant exhibits hemolytic activity in presence of up to 25 mM glucose supplementation, a phenotype that could be reverted by ccpA complementation. To further demonstrate that CcpA directly regulates the hemolysin expression, we performed an in silico analysis of the promoter of the SLS gene cluster and we verified the binding of CcpA to the promoter by electrophoretic mobility shift assays. This allowed us to define the CcpA binding site in the SLS promoter region of S. anginosus. In conclusion, we report for the first time the characterization of a potential virulence regulator in S. anginosus.

The competence system of Streptococcus anginosus and its use for genetic engineering

Streptococcus anginosus is considered a human commensal but improvements in species identification in recent years have highlighted its role as an emerging pathogen. However, our knowledge about the pathogenicity mechanisms in this species is scarce. One reason for this is the lack of published genetic manipulation techniques in the S. anginosus group. To establish a novel mutation technique we investigated the competence system of S. anginosus and created a Cre-recombinase-based mutation method that allows the generation of markerless gene deletions in S. anginosus. In silico analysis of the competence system demonstrated that S. anginosus encodes homologues for the vast majority of genes that are known to be essential for the transformation of S. pneumoniae. Analysis of transformation kinetics confirmed that S. anginosus SK52 possesses an S. pneumoniae-like competence development with a rapid increase of competence after treatment with Competence Stimulating Peptide (CSP), reaching a maximum transformation efficiency of 0.24% ± 0.08%. The combination of CSP-induced transformation and the Cre-lox system allows the efficient and fast creation of markerless gene deletions and will facilitate the investigation of the pathogenicity of S. anginosus on a genetic level.

Alterations in oral bacterial communities are associated with risk factors for oral and oropharyngeal cancer

Oral squamous cell carcinomas are a major cause of morbidity and mortality, and tobacco usage, alcohol consumption, and poor oral hygiene are established risk factors. To date, no large-scale case-control studies have considered the effects of these risk factors on the composition of the oral microbiome, nor microbial community associations with oral cancer. We compared the composition, diversity, and function of the oral microbiomes of 121 oral cancer patients to 242 age- and gender-matched controls using a metagenomic multivariate analysis pipeline. Significant shifts in composition and function of the oral microbiome were observed with poor oral hygiene, tobacco smoking, and oral cancer. Specifically, we observed dramatically altered community composition and function after tooth loss, with smaller alterations in current tobacco smokers, increased production of antioxidants in individuals with periodontitis, and significantly decreased glutamate metabolism metal transport in oral cancer patients. Although the alterations in the oral microbiome of oral cancer patients were significant, they were of substantially lower effect size relative to microbiome shifts after tooth loss. Alterations following tooth loss, itself a major risk factor for oral cancer, are likely a result of severe ecological disruption due to habitat loss but may also contribute to the development of the disease.

Sites of infection associated with Streptococcus anginosus group among children

Streptococcus anginosus group (SAG) are parts of normal flora of the oral cavity and associated with abscess forming in various sites on the body. Although the clinical features of infections caused by each member of the SAG in adults has been reported, it has not well been known in children. The aim of this study was to clarify the site of infections associated with individual SAG species among children. Medical records from March 2010 to July 2016 were reviewed at Tokyo Metropolitan Children's Medical Center. Any SAG species (S. anginosus, S. constellatus, or S. intermedius) isolated from clinical samples and recorded in the microbiological database were included for analysis. Analysis of 52 infectious episodes found that S. anginosus was most frequently isolated from the genitourinary tract, and 73% of genitourinary tract infection was balanoposthitis. All genitourinary tract infections were associated with S. anginosus. These findings were different from those of a previous study of adults. Of all the patients, 45 patients (87%) had polymicrobial infections. More than 70% of patients infected by S. anginosus and S. constellatus were co-infected by obligate anaerobes, in comparison with only 21% of S. intermedius cases. Among the obligate anaerobes species, Bacteroides spp. was significantly accompanied with S. anginosus. Susceptibility to penicillin, ampicillin, cefotaxime, erythromycin, clindamycin, levofloxacin, and vancomycin was 100%, 100%, 100%, 77%, 89%, 97% and 100%, respectively. S. anginosus was often isolated from balanoposthitis among children.

Comparative genomics and evolution of the amylase-binding proteins of oral streptococci

Background

Successful commensal bacteria have evolved to maintain colonization in challenging environments. The oral viridans streptococci are pioneer colonizers of dental plaque biofilm. Some of these bacteria have adapted to life in the oral cavity by binding salivary α-amylase, which hydrolyzes dietary starch, thus providing a source of nutrition. Oral streptococcal species bind α-amylase by expressing a variety of amylase-binding proteins (ABPs). Here we determine the genotypic basis of amylase binding where proteins of diverse size and function share a common phenotype.

Results

ABPs were detected in culture supernatants of 27 of 59 strains representing 13 oral Streptococcus species screened using the amylase-ligand binding assay. N-terminal sequences from ABPs of diverse size were obtained from 18 strains representing six oral streptococcal species. Genome sequencing and BLAST searches using N-terminal sequences, protein size, and key words identified the gene associated with each ABP. Among the sequenced ABPs, 14 matched amylase-binding protein A (AbpA), 6 matched amylase-binding protein B (AbpB), and 11 unique ABPs were identified as peptidoglycan-binding, glutamine ABC-type transporter, hypothetical, or choline-binding proteins. Alignment and phylogenetic analyses performed to ascertain evolutionary relationships revealed that ABPs cluster into at least six distinct, unrelated families (AbpA, AbpB, and four novel ABPs) with no phylogenetic evidence that one group evolved from another, and no single ancestral gene found within each group. AbpA-like sequences can be divided into five subgroups based on the N-terminal sequences. Comparative genomics focusing on the abpA gene locus provides evidence of horizontal gene transfer.

Conclusion

The acquisition of an ABP by oral streptococci provides an interesting example of adaptive evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-1005-7) contains supplementary material, which is available to authorized users.

Oesophageal cancer presenting as Lemierre's syndrome caused by Streptococcus anginosus

A 59-year-old man presented to the emergency department with complaints of dysphagia, right-sided neck swelling, fever and chills. Physical examination was remarkable for fever and tender swelling over the right side of the neck. Laboratory investigations revealed leucocytosis with neutrophilia. CT of the neck showed right internal jugular vein thrombosis with an overlying abscess and a nodular opacity in the right lung apex with air locules. He underwent surgical drainage of the neck abscess. Aerobic cultures from the drainage and blood cultures grew Streptococcus anginosus Given his initial complaint of dysphagia, upper endoscopy was performed which showed a mass in the upper oesophagus. Histopathology confirmed squamous cell carcinoma. The patient received 6 weeks of antibiotics therapy.

[Streptococcus milleri: An unusual cause of skull extensive osteomyelitis in an immunocompetent patient]

INTRODUCTION

Streptococcus milleri (Streptococcus anginosus, intermedius and constellatus) are commensal organisms, which can become pathogenic and cause infection with frequent abscess formation, local or metastatic extension. Osteomyelitis of the skull has been rarely reported in this type of infection.

CASE REPORT

Skull osteomyelitis due to Streptococcus milleri is reported in a 61-year-old immunocompetent man without any medical history, occurring 10 months after a head injury without any wound or complication at initial presentation. A progressive right parieto-occipital headache with worsening and increased acute phase reactants evoked a giant cell arteritis. After few days of corticosteroid therapy (0.5 mg/kg/day), diagnosis of subcutaneous abscess associated to an extensive osteomyelitis of the skull due to Streptococcus milleri was diagnosed. The outcome was favorable after drainage of one liter of pus, irrigation, debridement and antibiotherapy by amoxicillin for 8 weeks.

CONCLUSION

It is necessary to discuss the differential diagnosis of giant cell arteritis particularly when symptoms are unusual. Even a short-term corticosteroid therapy may dramatically exacerbate an undetected infection.

The sil Locus in Streptococcus Anginosus Group: Interspecies Competition and a Hotspot of Genetic Diversity

The Streptococcus Invasion Locus (Sil) was first described in Streptococcus pyogenes and Streptococcus pneumoniae, where it has been implicated in virulence. The two-component peptide signaling system consists of the SilA response regulator and SilB histidine kinase along with the SilCR signaling peptide and SilD/E export/processing proteins. The presence of an associated bacteriocin region suggests this system may play a role in competitive interactions with other microbes. Comparative analysis of 42 Streptococcus Anginosus/Milleri Group (SAG) genomes reveals this to be a hot spot for genomic variability. A cluster of bacteriocin/immunity genes is found adjacent to the sil system in most SAG isolates (typically 6–10 per strain). In addition, there were two distinct SilCR peptides identified in this group, denoted here as SilCR_SAG-A and SilCR_SAG-B, with corresponding alleles in silB. Our analysis of the 42 sil loci showed that SilCR_SAG-A is only found in Streptococcus intermedius while all three species can carry SilCR_SAG-B. In S. intermedius B196, a putative SilA operator is located upstream of bacteriocin gene clusters, implicating the sil system in regulation of microbe–microbe interactions at mucosal surfaces where the group resides. We demonstrate that S. intermedius B196 responds to its cognate SilCR_SAG-A, and, less effectively, to SilCR_SAG-B released by other Anginosus group members, to produce putative bacteriocins and inhibit the growth of a sensitive strain of S. constellatus.

Expressive aphasia caused by Streptococcus intermedius brain abscess in an immunocompetent patient

Background

Brain abscess is an uncommon but life-threatening infection. It involves a focal, intracerebral infection that begins in a localized area of cerebritis and develops into a collection of pus, surrounded by a well-vascularized capsule. Brain abscess still poses a significant problem in developing countries but rarely in developed countries. Predisposing factors vary in different parts of the world. With the introduction of antibiotics and imaging studies, the mortality rate has decreased between 5% and 15%. If left untreated it may lead to serious neurologic sequelae. The temporal lobe abscess can be caused by conditions like sinusitis, otitis media, dental infections, and mastoiditis if left untreated or partially treated. Additionally, in neurosurgical procedures like craniotomy, the external ventricular drain can get infected, leading to abscess formation.

Case presentation

We present the case study of an elderly female patient who presented with expressive aphasia caused by brain abscess, secondary to Streptococcus intermedius infection. The 72-year-old female with a medical history of hypertension came to hospital for evaluation with word-finding difficulty, an expressive aphasia that began a few days prior to presentation. Computed tomography of the head showed a left temporal lobe mass-like lesion, with surrounding vasogenic edema. The patient was empirically started on courses of antibiotics. The next day, she was subjected to magnetic resonance imaging of the brain, which showed a left temporal lobe septated rim-enhancing mass lesion, with bright restricted diffusion and diffuse surrounding vasogenic edema consistent with abscess. The patient was also seen by the neurosurgery department and underwent stereotactic, left temporal craniotomy, with drainage, and resection of abscess. Tissue culture grew S. intermedius sensitive to ampicillin sulbactam. Subsequently her expressive aphasia improved.

Conclusion

Brain abscess has a high mortality, however a significant proportion of patients with appropriately treated abscess recover completely and can survive without significant neurologic damage. Advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Biopsy of brain lesion with early initiation of appropriate antibiotics will change the outcome.

Draft Genome Sequence of Streptococcus anginosus BVI, a New Vaginal Pathogen Candidate

Streptococcus anginosus is a pathogen implicated in urogenital and gastroinstestinal tract infections. Here, we report the draft genome sequence of S. anginosus BVI, isolated from a bacterial vaginosis patient attending a prenatal care unit in Cali, Colombia. The genome sequence of BVI consists of 2,014,025 bp, encoding 2,008 predicted proteins.

Colorectal Cancer Associated with Streptococcus anginosus Bacteremia and Liver Abscesses

Streptococcus anginosus is part of the normal flora of the human gastrointestinal tract. Their ability to cause abscesses is very unique and sets them apart from the rest of the streptococci groups. While an association of group D streptococcus bacteremia and endocarditis with colorectal carcinoma is well established, S. anginosus infections are rarely implicated with colonic malignancy. We present a case of a 62-year-old male who presented to the hospital with fatigue and generalized abdominal pain. Computed tomography of the abdomen revealed multiple liver abscesses and rectal thickening. Blood cultures were found to grow S. anginosus bacteria. Colonoscopy revealed a rectal mass which was later confirmed to be rectal adenocarcinoma. This case presents an association between S. anginosus bacteremia and presence of colorectal cancer which has been highlighted in only a few case reports in literature. This should prompt clinicians to screen for colorectal cancer in patients with S. anginosus bacteremia.

Streptococcus intermedius Causing Necrotizing Pneumonia in an Immune Competent Female: A Case Report and Literature Review

We report a case of a 52-year-old immunocompetent Caucasian female treated for necrotizing Streptococcus intermedius pneumonia and review available literature of similar cases. Our patient presented with respiratory failure and required hospitalization and treatment in the intensive care unit. Moreover, she required surgical drainage of right lung empyema as well as decortication and resection. The review of literature revealed three cases of S. intermedius pneumonia, one of which was a mortality. Comparison of the published cases showed a highly varied prehospital course and radiological presentations, with a symptomatic phase ranging from 10 days to five months. Radiological findings varied from an isolated pleural effusion to systemic disease with the presence of brain abscesses. Immunocompetence appears to correlate well with the overall prognosis. In addition, smoking appears to be an important risk factor for S. intermedius pneumonia. In 2 (50%) of cases, pleural fluid analysis identified S. intermedius. In contrast, no organism was found in our patient, necessitating the acquisition of lung tissue sample for the diagnosis. In conclusion, both medical and surgical management are necessary for effective treatment of S. intermedius pneumonia. The outcome of treatment is good in immunocompetent individuals.

Relationship between the microbiota in different sections of the gastrointestinal tract, and the body weight of broiler chickens

In the poultry industry, many efforts have been undertaken to further improve the growth performance of broilers and identification and modulation of body weight (BW)-related bacteria could be one of the strategies to improve productivity. However, studies regarding the relationship between microbiota and BW are scarce. The objective of the present study was to investigate the relationship between microbiota and BW in different sections of the gastrointestinal tract (GIT). A total of twenty 18-day-old birds were selected based on the BW, and samples were collected from the three different sections of the GIT, which included the crop, ileum and cecum. Bacterial genomic DNA was extracted from the samples, and the V4 region of 16S rRNA gene were amplified. Amplicons were sequenced on Illumina MiSeq, and microbial communities were analyzed by using QIIME. In principal coordinate analysis, bacterial communities were clustered into three groups, based on the sections of GIT. Several BW-related bacterial groups were identified from linear regression analysis. At the genus level, Streptococcus from the ileum as well as Akkermansia in both ileum and cecum, were negatively related to BW, whereas Bifidobacterium in the ileum and Lactococcus in the cecum showed a positive correlation. The results from the present study showed that particular bacterial communities in the GIT were related to BW, and the study has broadened the understanding of the intestinal microbial ecosystem in broiler chickens.

Clinical and microbiological outcomes in patients with Streptococcus anginosus group bacteraemia identified through use of a rapid microarray assay

Limited data exist evaluating outcomes in patients with serious Streptococcus anginosus group infections, particularly bacteraemia. A retrospective, single-centre cohort study was conducted to characterize potential risk factors along with clinical and microbiological outcomes in patients with S. anginosus group bacteraemia (SAGB). Adult inpatients with SAGB identified using the Verigene Gram-positive blood culture assay between March 2013 and April 2014 were included. Patients aged ≤ 18 or >89 years, those with SAGB identified at an outside facility and those who were incarcerated were excluded. Differences between groups were explored using a Wilcoxon rank-sum test, χ2 test, Student's t-test or Fisher's exact test as appropriate and a two-tailed P value of ≤ 0.05 was considered statistically significant. The 34 patients who met the inclusion criteria were 57 ± 14 (mean ± SD) years old and had a median Charlson co-morbidity index of 4 [interquartile range (IQR) 1-6] and 10 (29%) were immunosuppressed at baseline. Almost half (47%) had received antibiotics in the previous 90 days. Twelve (35%) patients had gastrointestinal malignancies and the commonest source of bacteraemia was the gastrointestinal tract (53%). The primary species responsible for SAGB was S. anginosus (68%), and overall susceptibility to penicillin was 91%. Patients were most often treated with a β-lactam/β-lactamase inhibitor combination (36%) for a duration of 8 (IQR 4-13) days. Length of stay (LOS) and infection-related LOS were 10 (IQR 5-17) and 9 (IQR 4-12) days, respectively. Twenty [59%] patients achieved a clinical cure, while 29 (85%) achieved a microbiological cure. Four (12%) patients died and one patient was readmitted within 30  days. In the largest cohort of patients with SAGB to date, gastrointestinal malignancies may have been an important risk factor for SAGB, while rapid identification via a microarray assay likely contributed to improved disease recognition and timely pharmacological and non-pharmacological therapy.

Late prevertebral abscess with sinus following anterior cervical corpectomy and fusion

Anterior cervical discectomy/corpectomy and fusion is performed in degenerative, traumatic and neoplastic etiologies of the cervical spine. This procedure is highly successful and associated with fewer complications. The rates of early and late postoperative infection have been reported to be between 0.1% and 1.6%, the late infections are being very rare. We report a rare case of a 30-year-old HIV negative, non-diabetic male who developed a late prevertebral cervical abscess with discharging sinus over posterior triangle of neck 3 years after an anterior cervical C6 corpectomy with fibular grafting and buttress screw fixation performed elsewhere for traumatic fracture C6 vertebra. The abscess was drained using radical neck dissection approach with complete excision of sinus track and removal of the infected implant. On culture, the organism was found to be beta-hemolytic streptococci, for which appropriate antibiotics were administered postoperatively. The sinus tract completely healed in 3 months time. Late infection as a complication of anterior cervical spine surgeries is rare and is associated with esophageal perforation, implant migration, seeding of the deep prevertebral space with oropharyngeal flora, or from surgical site/bacteremia or with Zenker's diverticulum. Few cases have been reported till date, but none have presented with a sinus tract. We present a case of delayed prevertebral abscess after cervical spine instrumentation that followed abnormal path causing sinus track to be developed in the site (the posterior triangle of the neck) other than previous incision site. Exploring both triangles of the neck using radical neck dissection approach was essential for complete excision of sinus track, removal of screw and debridement.

Nonsurgical management of multiple splenic abscesses in an obese patient that underwent laparoscopic sleeve gastrectomy: case report and review of literature

Sleeve gastrectomy (SG) is a surgical weight-loss procedure. Splenic abscess is a rare complication of SG. Four cases of splenic abscess after SG have been reported, all managed by surgical intervention. We report the first documented case of multiple splenic abscesses following SG managed conservatively by an integrated medical treatment.

Detection of Group A Streptococcus from Pharyngeal Swab Samples by Bacterial Culture Is Challenged by a Novel mariPOC Point-of-Care Test

mariPOC is a novel point-of-care test system for rapid detection of respiratory tract infections. We compared the performance of the mariPOC test to that of bacterial culture for detecting group A streptococcus (GAS) in 219 pharyngitis patients (ages 1-64 years) and 109 healthy asymptomatic controls (ages 19-69 years). In addition, 42 patient samples were analyzed by quantitative PCR (qPCR). Of the 219 pharyngeal patient samples, 32 were positive in a GAS bacterial culture (prevalence 15%) and 65 (30%) in the mariPOC test. The amount of GAS in samples reported positive by the mariPOC test and negative by culture was, on average, 10-fold less than that of those positive in both methods. This indicated that the negative results in bacterial cultures were due to lower sensitivity. The qPCR results were positive and in line with the mariPOC results in 43% of the discordant samples studied. Two GAS culture-positive samples were negative by the mariPOC test. The prevalences of GAS in the control subjects were 2% and 6% by culture and mariPOC results, respectively. We conclude that the mariPOC antigen detection test is more sensitive than the conventional bacterial culture for the detection of GAS among symptomatic pharyngitis patients. The higher prevalence of GAS by the mariPOC test among symptomatic patients was probably not due to carriership, since among the control patients, the difference in the prevalence of GAS by the mariPOC test and culture was not nearly as high, 15% versus 4%, respectively. Clinical trials are needed to show the clinical importance of our findings.

Identification and characterization of a novel secreted glycosidase with multiple glycosidase activities in Streptococcus intermedius

Streptococcus intermedius is a known human pathogen and belongs to the anginosus group (S. anginosus, S. intermedius, and S. constellatus) of streptococci (AGS). We found a large open reading frame (6,708 bp) in the lac operon, and bioinformatic analysis suggested that this gene encodes a novel glycosidase that can exhibit β-d-galactosidase and N-acetyl-β-d-hexosaminidase activities. We, therefore, named this protein "multisubstrate glycosidase A" (MsgA). To test whether MsgA has these glycosidase activities, the msgA gene was disrupted in S. intermedius. The msgA-deficient mutant no longer showed cell- and supernatant-associated β-d-galactosidase, β-d-fucosidase, N-acetyl-β-d-glucosaminidase, and N-acetyl-β-d-galactosaminidase activities, and all phenotypes were complemented in trans with a recombinant plasmid carrying msgA. Purified MsgA had all four of these glycosidase activities and exhibited the lowest Km with 4-methylumbelliferyl-linked N-acetyl-β-d-glucosaminide and the highest kcat with 4-methylumbelliferyl-linked β-d-galactopyranoside. In addition, the purified LacZ domain of MsgA had β-d-galactosidase and β-d-fucosidase activities, and the GH20 domain exhibited both N-acetyl-β-d-glucosaminidase and N-acetyl-β-d-galactosaminidase activities. The β-d-galactosidase and β-d-fucosidase activities of MsgA are thermolabile, and the optimal temperature of the reaction was 40°C, whereas almost all enzymatic activities disappeared at 49°C. The optimal temperatures for the N-acetyl-β-d-glucosaminidase and N-acetyl-β-d-galactosaminidase activities were 58 and 55°C, respectively. The requirement of sialidase treatment to remove sialic acid residues of the glycan branch end for glycan degradation by MsgA on human α1-antitrypsin indicates that MsgA has exoglycosidase activities. MsgA and sialidase might have an important function in the production and utilization of monosaccharides from oligosaccharides, such as glycans for survival in a normal habitat and for pathogenicity of S. intermedius.