The pyogenic potential of the different Streptococcus anginosus group bacterial species: retrospective cohort study

Anovaginal Colonization by Group B Streptococcus and Streptococcus anginosus among Pregnant Women in Brazil and Its Association with Clinical Features

Streptococcus agalactiae (Group B Streptococcus; GBS) is a leading cause of neonatal invasive disease worldwide. GBS can colonize the human gastrointestinal and genitourinary tracts, and the anovaginal colonization of pregnant women is the main source for neonatal infection. Streptococcus anginosus, in turn, can colonize the human upper respiratory, gastrointestinal, and genitourinary tracts but has rarely been observed causing disease. However, in the last years, S. anginosus has been increasingly associated with human infections, mainly in the bloodstream and gastrointestinal and genitourinary tracts. Although anovaginal screening for GBS is common during pregnancy, data regarding the anovaginal colonization of pregnant women by S. anginosus are still scarce. Here, we show that during the assessment of anovaginal GBS colonization rates among pregnant women living in Rio de Janeiro, Brazil, S. anginosus was also commonly detected, and S. anginosus isolates presented a similar colony morphology and color pattern to GBS in chromogenic media. GBS was detected in 48 (12%) while S. anginosus was detected in 17 (4.3%) of the 399 anovaginal samples analyzed. The use of antibiotics during pregnancy and history of urinary tract infections and sexually transmitted infections were associated with the presence of S. anginosus. In turn, previous preterm birth was associated with the presence of GBS (p < 0.05). The correlation of GBS and S. anginosus with relevant clinical features of pregnant women in Rio de Janeiro, Brazil, highlights the need for the further investigation of these important bacteria in relation to this special population.

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

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

A rare case of aggressive pyogenic spondylitis with giant abscesses after vertebral augmentation

Although Streptococcus constellatus (SC), an opportunistic pathogen, can cause abscesses and empyema. The SC infection after vertebral augmentation (VA) can interfere with patients' daily living activities and can be life-threatening in severe cases. A 67-year-old male complained of lumbar pain for two months. The patient underwent percutaneous vertebroplasty of the second and third lumbar vertebrae two months ago. On admission, laboratory and imaging evidence suggested infection of the second and third lumbar vertebrae with bilateral psoas major and left lumbodorsal abscesses. After three weeks of empirical anti-infective therapy, abscess removal and the second and third lumbar vertebrae fusion with iliac bone graft were performed under general anesthesia. Intraoperative pathology and next-generation sequencing (NGS) examination of the pus suggested SC infection, and oral linezolid was given for 12 weeks after surgery. The infection was eventually cured and the patient achieved satisfactory function. In conclusion, pyogenic spondylitis due to SC infection after VA is a life-threatening complication. In addition to infectious disease consultation and routine etiological screening, NGS is important to identify infection with unknown pathogens. Surgery combined with sensitive antibiotics is appropriate for patients with progressive neurological deficits.

Multiple Lung Cavity Lesions, Thoracic Wall Abscess and Vertebral Destruction Caused by Streptococcus constellatus Infection: A Case Report

Disseminated infection caused by Streptococcus constellatus was seldom occurred. We reported a case of Streptococcus constellatus infection, presenting as multiple pulmonary cavities, thoracic wall abscess and vertebral destruction. The 37-year-old male had recurrent fever, chest wall swelling and pain, and lower limb numbness, he had weak physical condition and previously suffered from poorly controlled diabetes and severe periodontal disease for 3 years. Definite diagnosis of Streptococcus constellatus infection was made by metagenomic next‑generation sequencing (mNGS) in abscess drainage fluid. Systemic antibiotics and thoracic wall drainage were given, and the pulmonary cavity and the thoracic intermuscular abscess were significantly decreased. Few to no study reported the disseminated infection (pulmonary cavities, thoracic wall abscess and vertebral destruction) caused by Streptococcus constellatus. This case report highlighted the importance of mNGS for accurate diagnosis, as well as the timely drainage and antibiotics for effective treatment of Streptococcus constellatus infection.

Microbiological Epidemiology of Invasive Infections Due to Non-Beta-Hemolytic Streptococci, France, 2021

Non-beta-hemolytic streptococci (NBHS), also referred to as viridans streptococci, represent an underestimated cause of human invasive diseases. Their resistance to antibiotics, including beta-lactam agents, often complicate their therapeutic management. A prospective multicenter study was conducted by the French National Reference Center for Streptococci between March and April 2021 to describe the clinical and microbiological epidemiology of invasive infections due to NBHS, excluding pneumococcus. A total of 522 NBHS invasive cases were collected. Distribution among streptococcal groups was: Streptococcus anginosus (33%), Streptococcus mitis (28%), Streptococcus sanguinis (16%), Streptococcus bovis/equinus (15%), Streptococcus salivarius (8%), and Streptococcus mutans (<1%). Median age of infection was 68 years old (range <1 day to 100 years). Cases were more frequent in male patients (gender ratio M/F 2.1:1) and manifested mainly as bacteremia without focus (46%), intra-abdominal infections (18%) and endocarditis (11%). All isolates were susceptible to glycopeptides and displayed low-level inherent gentamicin resistance. All isolates of the S. bovis/equinus, S. anginosus, and S. mutans groups were susceptible to beta-lactams. Conversely, nonsusceptibility to beta-lactams was found in 31%, 28%, and 52% of S. mitis, S. salivarius, and S. sanguinis isolates, respectively. The screening for beta-lactam resistance using the recommended one unit benzylpenicillin disk screening failed to detect 21% of resistant isolates (21/99). Last, overall resistance rates to the alternative anti-streptococcal molecules clindamycin and moxifloxacin were 29% (149/522) and 1.6% (8/505), respectively. IMPORTANCE NBHS are recognized as opportunistic pathogens particularly involved in infections of the elderly and immunocompromised patients. This study underlines their importance as common causes of severe and difficult-to-treat infections such as endocarditis. Although species of the S. anginosus and S. bovis/equinus groups remain constantly susceptible to beta-lams, resistance in oral streptococci exceeds 30% and screening techniques are not fully reliable. Therefore, accurate species identification and antimicrobial susceptibility testing by MICs determination appears essential for the treatment of NBHS invasive infections, together with continued epidemiological surveillance.

Diversity of CRISPR-Cas type II-A systems in Streptococcus anginosus

Streptococcus anginosus is a commensal Streptococcal species that is often associated with invasive bacterial infections. However, little is known about its molecular genetic background. Many Streptococcal species, including S. anginosus, harbor clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems. A CRISPR-Cas type II-A system as well as a type II-C system have been reported for this species. To characterize the CRISPR-Cas type II systems of S. anginosus in more detail, we conducted a phylogenetic analysis of Cas9 sequences from CRISPR-Cas type II systems with a special focus on streptococci and S. anginosus. In addition, a phylogenetic analysis of S. anginosus strains based on housekeeping genes included in MLST analysis, was performed. All analyzed Cas9 sequences of S. anginosus clustered with the Cas9 sequences of CRISPR type II-A systems, including the Cas9 sequences of S. anginosus strains reported to harbor a type II-C system. The Cas9 genes of the CRISPR-Cas type II-C systems of other bacterial species separated into a different cluster. Moreover, analyzing the CRISPR loci found in S. anginosus, two distinct csn2 genes could be detected, a short form showing high similarity to the canonical form of the csn2 gene present in S. pyogenes. The second CRISPR type II locus of S. anginosus contained a longer variant of csn2 with close similarities to a csn2 gene that has previously been described in Streptococcus thermophilus. Since CRISPR-Cas type II-C systems do not contain a csn2 gene, the S. anginosus strains reported to have a CRISPR-Cas type II-C system appear to carry a variation of CRISPR-Cas type II-A harboring a long variant of csn2.

Pyogenic Liver Abscess Growing Streptococcus constellatus in an Elderly Female With Recent Diverticulitis: A Case Report

Pyogenic liver abscess (PLA) is known as a pus-filled lesion found in the liver which can quickly become fatal if not found and treated in a timely manner. The most common group of bacteria found in PLA is the Streptococcus Anginosus Group (SAG). Patients with PLA usually present with fever and right upper quadrant abdominal pain which can at times be referred to the right shoulder owing to dermatomal involvement. We present a case where a patient with a past medical history significant for recent diverticulosis presenting with a left lower quadrant abdominal pain, fever, and hypotension and on further workup was found to have a PLA. Blood cultures and cultures from the abscess grew Streptococcus constellatus. This bacteria is part of the SAG group however, it is rarely found in PLA and bloodstream.

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.

Aggressive Pyogenic Spondylitis Caused by S. constellatus: A Case Report

Streptococcus constellatus (SC) is a species of Streptococcus belonging to the Streptococcus anginosus group, along with Streptococcus anginosus and Streptococcus intermedius. Despite its commensal nature, underlying risk factors and medical conditions might lead to various anatomic site infections caused by this opportunistic pathogen. Although SC infections have mostly been associated with bacteremia, some case reports of abscess and empyema formation have been documented. Herein, we report a case of a middle-aged female patient who initially presented with radiculopathy symptoms. Subsequent neurologic imaging revealed a pyogenic abscess along paravertebral muscles, which was found to be caused by SC. The patient was successfully treated with abscess drainage from the lumbar zone and antibiotics, and the symptoms of radiculopathy have completely resolved.

The bacteriocin Angicin interferes with bacterial membrane integrity through interaction with the mannose phosphotransferase system

In a natural environment, bacteria are members of multispecies communities. To compete with rival species, bacteria produce antimicrobial peptides (AMPs), called bacteriocins. Bacteriocins are small, cationic, ribosomally synthesized peptides, which normally inhibit closely related species of the producing organism. Bacteriocin production is best studied in lactic bacteria (LAB). Streptococcus anginosus, belonging to LAB, produces the potent bacteriocin Angicin, which shows inhibitory activity against other streptococci, Listeria monocytogenes and vancomycin resistant Enterococcus faecium (VRE). Furthermore, Angicin shows a high resistance toward pH changes and heat, rendering it an interesting candidate for food preservation or clinical applications. The inhibitory activity of Angicin depends on the presence of a mannose phosphotransferase system (Man-PTS) in target cells, since L. monocytogenes harboring a deletion in an extracellular loop of this system is no longer sensitive to Angicin. Furthermore, we demonstrated by liposome leakage and pHluorin assays that Angicin destroys membrane integrity but shows only low cytotoxicity against human cell lines. In conclusion, we show that Angicin has a detrimental effect on the membrane of target organisms by using the Man-PTS as a receptor.

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

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

The Role of SilX in Bacteriocin Production of Streptococcus anginosus

Streptococcus anginosus produces the novel antimicrobial peptide Angicin, which inhibits Gram positive microorganisms and is classified as a group IId bacteriocin. Production of Angicin is regulated by the quorum sensing system Sil (Streptococcus invasion locus), which is located adjacent to the bacteriocin gene cluster. Within this genetic region a typical CAAX protease is encoded, which was designated SilX. Nelfinavir, a HIV protease inhibitor, led to a concentration dependent reduction in antimicrobial activity, presumably through the inhibition of SilX. Concentrations exceeding 25 μM Nelfinavir caused a complete abolishment of bacteriocin activity against Listeria monocytogenes. These results are supported by the observation, that a SilX deletion mutant of S. anginosus strain BSU 1211 no longer inhibits the growth of L. monocytogenes. Antimicrobial activity could be restored by addition of synthetically synthesized mature SilCR, implying that SilX may be involved in the export and processing of the signal peptide SilCR. Some CAAX proteases have been reported to provide immunity against bacteriocins. However, in a radial diffusion assay the deletion mutant S. anginosus BSU 1211ΔSilX showed no sensitivity toward Angicin arguing against a role of SilX in the immunity of S. anginosus. The putative processing of the signal peptide SilCR indicates a novel function of the CAAX protease SilX, in the context of S. anginosus bacteriocin production.

Disseminated Streptococcus anginosus invasive infection with intracranial subdural abscess formation

We report the case of a 67-year-old woman with disseminated Streptococcus anginosus invasive infection. Even under a maximal dose of susceptible antibiotics, her condition was complicated by pulmonary septic emboli and intracranial subdural abscess. Effective antibiotics and emergent surgical drainage were performed, but the sequelae of aphasia and hemiplegia remained. Underlying immunocompromised conditions of diabetes mellitus and monoclonal gammopathy of unknown significance might partially affect the clinical course of invasive S. anginosus infection. Once the infection becomes invasive, it can be refractory and difficult to treat. Clinicians should acknowledge the characteristics of invasive S. anginosus infection.

Reduction of surgical site infections in pediatric patients with complicated appendicitis: Utilization of antibiotic stewardship principles and quality improvement methodology

BACKGROUND

The rate of surgical site infection (SSI) after appendectomy for complicated appendicitis (CA) was high at our children's hospital. We hypothesized that practice standardization, including obtaining intra-operative cultures of abdominal fluid in patients with CA, would improve outcomes and reduce healthcare utilization after appendectomy.

METHODS

A quality improvement team designed and implemented a clinical practice guideline for CA that included obtaining intra-operative culture of purulent fluid, administering piperacillin/tazobactam for at least 72 h post-operatively, and transitioning to oral antibiotics based on intraoperative culture data. We compared outcomes before and after guideline implementation.

RESULTS

From July 2018-October 2019, 63 children underwent appendectomy for CA compared to 41 children from January-December 2020. Compliance with our process measures are as follows: Intra-operative culture was obtained in 98% of patients post-implementation; 95% received at least 72 h of piperacillin-tazobactam; and culture results were checked on all patients. Culture results altered the choice of discharge antibiotics in 12 (29%) of patients. All-cause morbidity (SSI, emergency department visit, readmission to hospital, percutaneous drain, unplanned return to operating room) decreased significantly from 35% to 15% (p=0.02). Surgical site infections became less frequent, occurring on average every 27 days pre-implementation and every 60 days after care pathway implementation (p=0.03).

CONCLUSIONS

Utilization of a clinical practice guideline was associated with reduced morbidity after appendectomy for CA. Intra-operative fluid culture during appendectomy for CA appears to facilitate the selection of appropriate post-operative antibiotics and, thus, minimize SSIs and overall morbidity.

Angicin, a novel bacteriocin of Streptococcus anginosus

As a conserved defense mechanism, many bacteria produce antimicrobial peptides, called bacteriocins, which provide a colonization advantage in a multispecies environment. Here the first bacteriocin of Streptococcus anginosus, designated Angicin, is described. S. anginosus is commonly described as a commensal, however it also possesses a high pathogenic potential. Therefore, understanding factors contributing to its host colonization and persistence are important. A radial diffusion assay was used to identify S. anginosus BSU 1211 as a potent bacteriocin producer. By genetic mutagenesis the background of bacteriocin production and the bacteriocin gene itself were identified. Synthetic Angicin shows high activity against closely related streptococci, listeria and vancomycin resistant enterococci. It has a fast mechanism of action and causes a membrane disruption in target cells. Angicin, present in cell free supernatant, is insensitive to changes in temperature from - 70 to 90 °C and pH values from 2 to 10, suggesting that it represents an interesting compound for potential applications in food preservation or clinical settings.

An empyema caused by Streptococcus constellatus in an older immunocompetent patient: Case report

RATIONALE

Empyema caused by Streptococcus constellatus is rare in patients without underlying diseases. However, the importance of the Streptococcus anginosus group, which consists of S constellatus, S anginosus, and Streptococcus intermedius, as causative organisms of empyema has been increasing.

PATIENT CONCERNS

A 78-year-old man initially presented with dyspnea and chills for 4 days. He had no medical history.

DIAGNOSIS

Chest X-ray and chest computed tomography showed a large and multiloculated pleural effusion with an air bubble on the right side. Cultivation of the pleural effusion using clone library analysis of the 16S rRNA gene revealed S constellatus positivity.

INTERVENTIONS

The patient was treated by drainage of the pleural effusion and intravenous ceftriaxone and clindamycin for the possibility of anaerobes, followed by 10 weeks of oral antibiotics.

OUTCOMES

On the 11th day of admission, the thoracic drainage tube was removed. After 1 year of treatment, there were no sequelae of empyema.

LESSONS

Although S constellatus can cause serious infections in patients with underlying diseases and immunosuppression, physicians need to consider S constellatus infection in community-acquired empyema in elderly individuals. It should be treated with early pleural drainage and antibiotics to avoid surgical decortication and prolonged hospitalization.

Streptococcus intermedius: unusual presentation and complication of lung abscess

We report a case of a 54-year-old immunocompetent male who had lung abscess secondary to Streptococcus intermedius that led to discitis by contiguous spread of infection. He initially presented with constant chest pain for 6 weeks that radiated to lower back, with no fever, chills or weight loss. He denied smoking cigarettes, alcohol use or any illicit drug. On investigation, a mass was identified on the posterior medial aspect of the right lower lobe with direct infiltration into right side of the T5-T6 vertebral bodies. Histopathology identified organising pneumonia with abscess. Tissue cultures showed S. intermedius, and were negative for other microorganisms. This case highlights a rare presentation of S intermedius discitis by contiguous spread of infection from posterior right lower lobe lung abscess. S intermedius usually occurs in older patients with pulmonary infections complicated with pleural effusion or lung abscess, but can present in young patients with no clear symptoms of lung infection, like our patient.

Diversity of β-hemolysins produced by the human opportunistic streptococci

The genus Streptococcus infects a broad range of hosts, including humans. Some species, such as S. pyogenes, S. agalactiae, S. pneumoniae, and S. mutans, are recognized as the major human pathogens, and their pathogenicity toward humans has been investigated. However, many of other streptococcal species have been recognized as opportunistic pathogens in humans, and their clinical importance has been underestimated. In our previous study, the Anginosus group streptococci (AGS) and Mitis group streptococci (MGS) showed clear β-hemolysis on blood agar, and the factors responsible for the hemolysis were homologs of two types of β-hemolysins, cholesterol-dependent cytolysin (CDC) and streptolysin S (SLS). In contrast to the regular β-hemolysins produced by streptococci (typical CDCs and SLSs), genetically, structurally, and functionally atypical β-hemolysins have been observed in AGS and MGS. These atypical β-hemolysins are thought to affect and contribute to the pathogenic potential of opportunistic streptococci mainly inhabiting the human oral cavity. In this review, we introduce the diverse characteristics of β-hemolysin produced by opportunistic streptococci, focusing on the species/strains belonging to AGS and MGS, and discuss their pathogenic potential.

Aggressive Presentation of Streptococcus constellatus

The Streptococcus anginosus group (SAG) consists of three bacteria (Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus) that are known commensals of the upper respiratory, digestive, and reproductive tracts. While a rare occurrence, these bacteria have the capability of causing devastating pyogenic infections and ensuing abscess formations. It is often difficult to distinguish this group as a contaminant or the offending organism (as it is often cultured in respiratory specimens); therefore, it is important to understand the risk factors, clinical presentation, and diagnostic findings that can provide a more accurate picture to identify the organism. Published literature pertaining to the SAG group has rarely documented any invasive surgical intervention that was undertaken for treatment. We describe a case of a 59-year-old male who presented for persistent chest pain and profuse productive cough weeks after he was diagnosed with a left lower extremity deep vein thrombosis and right-sided pulmonary embolism. The patient was found to have a rapidly evolving Streptococcus constellatus right middle lobe lung abscess complicated by a right hemithorax empyema. Management included an exploration of the right chest, decortication, parietal pleurectomy, and partial excision of the right middle lobe. Subsequently, the patient completed four weeks of antibiotics with ertapenem.

Streptococcus anginosus and Phalangeal Osteomyelitis: An Unusual Presentation

Introduction

Osteomyelitis of the hand is a rare entity and almost always occurs after catastrophic injuries. Streptococcus anginosus is a part of the normal microbial flora of the oral cavity and the gastrointestinal tract. It is frequently associated with purulent infections in several anatomic locations but rarely harms bony structures. The occurrence of osteomyelitis of the hand caused by this microorganism is very unusual.

Case Report

We report the clinical case of a 58-year-old Caucasian male, ex-smoker, with a medical history of a chronic hepatitis C virus infection, liver cirrhosis, and diabetes mellitus that developed extensive osteomyelitis of the middle and distal phalanx of his right ring finger caused by S. anginosus and needed amputation for infection control. He had suffered a cut with a steel grinder on that finger 2 weeks before coming to the emergency department. He was also had been submitted to a dental procedure (tooth extraction) the exact day before the trauma. We believe that the most likely origin of the osteomyelitis was a transient bacteremia caused by the dental procedure that led to hematogenous seeding of several oral commensal microbes, including S. anginosus, that ended up infecting an area with low immune capacity due to the trauma.

Conclusion

S. anginosus causes purulent infections in multiple locations and affects more often immunocompromised patients, especially those with cirrhosis and diabetes mellitus. Even though it is not often associated with osteomyelitis, we should have a high level of suspicion if the patient has an intraoral disease or a history of dental or gastrointestinal procedures. The infection is severe, often leading to the need for radical debridements.

A diagnostic algorithm for detection of urinary tract infections in hospitalized patients with bacteriuria: The "Triple F" approach supported by Procalcitonin and paired blood and urine cultures

For acute medicine physicians, distinguishing between asymptomatic bacteriuria (ABU) and clinically relevant urinary tract infections (UTI) is challenging, resulting in overtreatment of ABU and under-recognition of urinary-source bacteraemia without genitourinary symptoms (USB). We conducted a retrospective analysis of ED encounters in a university hospital between October 2013 and September 2018 who met the following inclusion criteria: Suspected UTI with simultaneous collection of paired urinary cultures and blood cultures (PUB) and determination of Procalcitonin (PCT). We sought to develop a simple algorithm based on clinical signs and PCT for the management of suspected UTI. Individual patient presentations were retrospectively evaluated by a clinical "triple F" algorithm (F1 ="fever", F2 ="failure", F3 ="focus") supported by PCT and PUB. We identified 183 ED patients meeting the inclusion criteria. We introduced the term UTI with systemic involvement (SUTI) with three degrees of diagnostic certainty: bacteremic UTI (24.0%; 44/183), probable SUTI (14.2%; 26/183) and possible SUTI (27.9%; 51/183). In bacteremic UTI, half of patients (54.5%; 24/44) presented without genitourinary symptoms. Discordant bacteraemia was diagnosed in 16 patients (24.6% of all bacteremic patients). An alternative focus was identified in 67 patients, five patients presented with S. aureus bacteremia. 62 patients were diagnosed with possible UTI (n = 20) or ABU (n = 42). Using the proposed "triple F" algorithm, dichotomised PCT of < 0.25 pg/ml had a negative predictive value of 88.7% and 96.2% for bacteraemia und accordant bacteraemia respectively. The application of the algorithm to our cohort could have resulted in 33.3% reduction of BCs. Using the diagnostic categories "possible" or "probable" SUTI as a trigger for initiation of antimicrobial treatment would have reduced or streamlined antimicrobial use in 30.6% and 58.5% of cases, respectively. In conclusion, the "3F" algorithm supported by PCT and PUB is a promising diagnostic and antimicrobial stewardship tool.

Splenic abscess caused by Streptococcus anginosus bacteremia secondary to urinary tract infection: a case report and literature review

Organ abscesses caused by Streptococcus anginosus are relatively rare. We report the case of an elderly woman with splenic abscess caused by S. anginosus bacteremia after urinary tract infection. An 82-year-old woman had a history of frequency of urination, urgency, and fever with chills for over 10 days prior to admission. An abdominal computed tomography (CT) scan performed in the emergency room revealed a low-density lesion in the spleen, kidney cysts, some exudation around the kidney, and cystitis should be valued. She was treated with ceftriaxone and imipenem/cilastatin. After admission, the blood culture yielded positive results for S. anginosus. A contrast-enhanced abdominal CT scan showed that the low-density lesion previously found in the spleen was smaller than before. After percutaneous drainage of the splenic abscess and treatment with piperacillin/tazobactam based on the antibiotic sensitivity pattern, repeated abdominal CT scan revealed a significant reduction in the low-density lesion. The patient was discharged without recurrence or complications. A systematic review of organ abscess caused by S. anginosus bacteremia was performed. To our knowledge, there has been no report of splenic abscess caused by S. anginosus bacteremia secondary to urinary system tract infection, although urinary tract infections are also an important source.

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

BACKGROUND

Data on patients with invasive Streptococcus anginosus group (SAG) infections is limited, as it's been considered commensal bacteria in the human microbiota. We conducted an analysis of SAG infections to assist clinicians in understanding their burden and clinical outcomes.

METHODS

A retrospective study of medical records, identifying invasive SAG bacteria of sterile-site isolates that were managed from May 2015 to April 2017, at a tertiary care hospital in Riyadh, Saudi Arabia. Demographic data, clinical presentation, site of infection, antibiotic use, and outcome were recorded and analyzed to identify factors associated with poor outcome and/or polymicrobial growth.

RESULTS

We identified 105 cases of SAG infections in adults, with 52% of the patients being male and the mean age of 52.4 years with comorbidities occurring in more than half of the cases such as diabetes (38%) and malignancy (15%). Overall mortality was 6%, and it was statistically associated with age older than 65 years, polymicrobial growth and a history of malignancy. The infection frequencies were skin and soft tissue infections (SSTI; 55%), intra-abdominal infections (24%), bacteremia (14%), genitourinary infections (8.5%), and pleuropulmonary infections (5%). Abscesses accounted for 68% of cases. Polymicrobial infection (46%) with Enterobacteriaceae and Gram-negative anaerobes coincided with SAG infection. Polymicrobial growth was significantly associated with abscess formation, intra-abdominal source of infections, and poor outcome. In addition, death in patients with SAG was statistically associated with patients older than 65 years of age and those with history of cancer or transplant.

CONCLUSION

SSTIs and intra-abdominal infections are the most common clinical presentations in our cohort. Bacteremia was uncommon; however, the prognosis is less favorable. Overall susceptibility to penicillin was 91%, therefore β-lactam antibiotics are the drug of choice and additional coverage for anaerobic and gram-negative bacteria should be considered for intra-abdominal collection and solid or organ abscesses.

Streptococcus constellatus Causing Empyema and Sepsis, Necessitating Early Surgical Decortication

Streptococcus constellatus is an oropharyngeal commensal Gram-positive coccus, frequently associated with the respiratory tract. S. constellatus is part of the Streptococcus anginosus or milleri group, which has traditionally been considered to have propensity to cause empyema and purulent abscesses, a property that is sometimes overlooked as the severity of infections it causes may have a varying degree. In this case, we present the case of a 54-year-old male with known liver cirrhosis who developed a severe empyema during an acute liver failure episode, requiring extensive decortication and prolonged hospital admission.

From Normal Flora to Brain Abscesses: A Review of Streptococcus intermedius

Streptococcus intermedius is a β-hemolytic Gram-positive member of the Streptococcus anginosus group (SAG). Despite being a part of the normal microbiota, it is one of the most common pathogens associated with brain and liver abscesses and thoracic empyema, increasing as a result the morbidity and mortality rates in affected patients. Though there are numerous published case reports on S. intermedius infections, it is still understudied compared to other SAG members. Our knowledge of the genomic factors contributing to its dissemination to the brain and abscess development is also limited to few characterized genes. In this review, we summarize our current knowledge on S. intermedius identification methods, virulence factors, and insight provided by the whole-genome and correlate patients’ metadata, symptoms, and disease outcome with S. intermedius infections in 101 recent case reports obtained from PubMed. This combined information highlights the gaps in our understanding of S. intermedius pathogenesis, suggesting future research directions to unveil the factors contributing to abscess development.

Does bacterial colonization during embryo transfer have an impact on pregnancy rate in ICSI? : Tunisian preliminary results

INTRODUCTION

Embryos' transfer into the uterine cavity remains a limiting factor in the success of intracytoplasmic sperm injection (ICSI). This study aimed to evaluate the impact of cervico-vaginal colonization on ICSI outcomes.

MATERIEL AND METHODS

Longitudinal, prospective and analytical study, conducted from February 1 st to October 31 st, 2017. On the day of embryos' transfer, patients with the following criteria were included: Age ≤ 40, normal uterine ultrasound and hysteroscopy, first or second attempt of ICSI, use of fresh semen and transfer of at least one good quality embryo. Three samples were done for microbiological analysis: vaginal secretions, cervical mucus and the tip of the transfer catheter.

RESULTS

The study included 40 patients. Pregnancy rate was 52.5 %. Catheter contamination occurred in nine cases (22.5 %). The most frequently isolated bacteria were Streptococcus anginosus (37 % of cases), Gardnerella vaginalis (27 % of cases) and Streptococcus agalactiae (18 % of cases). In all cases of contamination, the same bacteria were found also in the vagina and cervical mucus. In cases of contamination with Gardnerella vaginalis, the study of vaginal flora showed bacterial vaginosis. No pregnancy was obtained when contamination of the transfer catheter occurred. In the absence of contamination, pregnancy rate was 61.2 % (ρ = 0.003). Both populations (patients with catheter contamination and patients without catheter contamination) were comparable regarding epidemiological characteristics and ICSI attempt data.

CONCLUSION

Contamination of the transfer catheter by cervical-vaginal bacteria appears to affect IVF results. Systematic antibiotic prophylaxis could be proposed to reduce this negative impact.

COMPLICATED PNEUMONIA WITH EMPYEMA CAUSED BY STREPTOCOCCUS ANGINOSUS IN A CHILD

Objective:

To highlight the pathogenicity of Streptococcus anginosus, which is rare in pediatric patients, but can cause severe infections that are known to have a better outcome when treated early with interventional procedures and prolonged antibiotic therapy.

Case

description: The patient is a 6-year-old boy with global developmental delay, examined in the emergency room due to fever and respiratory distress. The physical examination and diagnostic workout revealed complicated pneumonia with empyema of the left hemithorax; he started antibiotic therapy and underwent thoracic drainage. Pleural fluid cultures grew Streptococcus anginosus. On day 11, the child had a clinical deterioration with recurrence of fever, hypoxia, and respiratory distress. At this point, considering the causative agent, he was submitted to video-assisted thoracoscopic decortication, with good progress thereafter.

Comments:

Streptococcus anginosus is a commensal bacterium of the human oral cavity capable of causing severe systemic infections. Although reports of complicated thoracic infections with this agent are rare in the pediatric population, they have been increasing in adults. Streptococcus anginosus has a high capacity to form abscess and empyema, requiring different therapeutic approaches when compared to complicated pneumonia caused by other agents.

Antimicrobial resistance of bacteraemia in the emergency department of a German university hospital (2013-2018): potential carbapenem-sparing empiric treatment options in light of the new EUCAST recommendations

Background

This study investigated predominant microorganisms causing community-onset bacteraemia at the medical emergency department (ED) of a tertiary-care university hospital in Germany from 2013 to 2018 and their antimicrobial susceptibility patterns.

Methods

Antimicrobial resistance patterns in patients with positive blood cultures presenting to an internal medicine ED were retrospectively analysed.

Results

Blood cultures were obtained at 5191 of 66,879 ED encounters, with 1013 (19.5%) positive results, and true positive results at 740 encounters (diagnostic yield, 14.3%). The most frequently isolated relevant microorganisms were Enterobacterales (n = 439, 59.3%), Staphylococcus aureus (n = 92, 12.4%), Streptococcus pneumoniae (n = 34, 4.6%), Pseudomonas aeruginosa (n = 32, 4.3%), Streptococcus pyogenes (n = 16, 2.2%), Enterococcus faecalis (n = 18, 2.4%), and Enterococcus faecium (n = 12, 1.6%). Antimicrobial susceptibility testing revealed a high proportion of resistance against ampicillin-sulbactam in Enterobacterales (42.2%). The rate of methicillin-resistant Staphylococcus aureus was low (0.4%).

Piperacillin-tazobactam therapy provided coverage for 83.2% of all relevant pathogens using conventional breakpoints. Application of the new European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations increased the percentage of susceptible isolates to high-dose piperacillin-tazobactam to 92.8% (p < 0.001). Broad-spectrum carbapenems would only cover an additional 4.8%. The addition of vancomycin or linezolid extended coverage by just 1.7%.

Conclusions

Using an ureidopenicillin-beta-lactamase inhibitor combination at the high dose suggested by the new EUCAST recommendations provided nearly 93% coverage for relevant pathogens in patients with suspected bloodstream infection in our cohort. This might offer a safe option to reduce the empiric use of carbapenems. Our data support the absence of a general need for glycopeptides or oxazolidinones in empiric treatment.

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.