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

Streptococcus anginosus in the development and treatment of precancerous lesions of gastric cancer

The microbiota is strongly association with cancer. Studies have shown significant differences in the gastric microbiota between patients with gastric cancer (GC) patients and noncancer patients, suggesting that the microbiota may play a role in the development of GC. Although Helicobacter pylori (H. pylori) infection is widely recognized as a primary risk factor for GC, recent studies based on microbiota sequencing technology have revealed that non-H. pylori microbes also have a significant impact on GC. A recent study discovered that Streptococcus anginosus (S. anginosus) is more prevalent in the gastric mucosa of patients with GC than in that of those without GC. S. anginosus infection can spontaneously induce chronic gastritis, mural cell atrophy, mucoid chemotaxis, and heterotrophic hyperplasia, which promote the development of precancerous lesions of GC (PLGC). S. anginosus also disrupts the gastric barrier function, promotes the proliferation of GC cells, and inhibits apoptosis. However, S. anginosus is underrepresented in the literature. Recent reports suggest that it may cause precancerous lesions, indicating its emerging pathogenicity. Modern novel molecular diagnostic techniques, such as polymerase chain reaction, genetic testing, and Ultrasensitive Chromosomal Aneuploidy Detection, can be used to gastric precancerous lesions via microbial markers. Therefore, we present a concise summary of the relationship between S. anginosus and PLGC. Our aim was to further investigate new methods of preventing and treating PLGC by exploring the pathogenicity of S. anginosus on PLGC.

Virulence factors of Streptococcus anginosus - a molecular perspective

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

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

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

Practical Review of the Management of Animal Bites

Animal bites are common worldwide. Due to the plethora of animals, there are diverse pathogens with specific associated risks and treatment algorithms. It is crucial to understand these to develop and execute appropriate management plans. This practical review was designed to amalgamate the most common bites worldwide and synthesize data to help guide treatment plans.

METHODS

A PubMed literature search was performed focusing on the major animal bites. High-level studies were preferred and analyzed but lower-level studies were also used if high-level studies did not exist.

RESULTS

The tables presented in this article cover the pertinent information regarding the incidence, common presentation, initial treatment, and potential complications associated with bites from dogs, cats, horses, rodents, snakes, marine life, and spiders. Many of the pathogens associated with the bites are treatable with various and somewhat common antimicrobials, though some are less easy to access. Basic irrigation, debridement, and wound culture are common to almost every animal and should be the first step in treatment.

CONCLUSIONS

Based on the current studies, the most important factor in treating animal bites is timely presentation to a medical facility and/or physician. It is critical that the offending animal be accurately identified to help guide medical and surgical algorithms, including specific antimicrobial treatment guided by the most commonly presenting pathogens specific to certain animals.

Lemierre Syndrome: Unusual Presentation With Superior Ophthalmic Vein Thrombosis

ABSTRACT

Lemierre syndrome (LS) is a rare, but serious condition most commonly associated with oropharyngeal bacterial infection. Infection results in thrombophlebitis of the internal jugular vein and its tributaries. It usually affects previously healthy young adults. The authors report an unusual case of an elderly patient with penicillin allergy who developed Lemierre syndrome from an odontogenic infection (Streptococcus intermedius) resistant to clindamycin. She developed thrombosis of the internal jugular vein and superior ophthalmic vein resulting in visual changes. Treatment required incision and drainage, intravenous antibiotics and anticoagulation. Antibiotics were tailored to culture and sensitivities after testing response to a beta-lactam. With antibiotic resistance increasing, investigation of penicillin allergies is warranted for severe head and neck infections.

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.

Complications of Otitis Media and Sinusitis Caused by Streptococcus anginosus Group Organisms in Children

BACKGROUND

The Streptococcus anginosus group (SAG, S. anginosus, S. intermedius and S. constellatus) are often associated with severe disease and abscess formation. In our institution, we observed an apparent increase in frequency of intraorbital and intracranial infections resulting from SAG at Texas Children's Hospital. We undertook a retrospective review to describe the frequency and clinical features of these infections.

METHODS

We reviewed the database of the microbiology laboratory at Texas Children's Hospital from 2011 to 2018 for SAG-positive cultures. Cases included were those associated with (1) either otitis media or sinusitis and (2) Pott's puffy tumor, orbital abscesses, mastoiditis, epidural abscesses, subdural empyema, brain parenchymal abscesses or dural enhancement by imaging. The number of overall diagnoses were determined using diagnostic codes and used to estimate the proportion of disease caused by SAG.

RESULTS

Ninety-five cases were identified meeting inclusion criteria. The median age of patients was 11.4 years, and 75.8% were previously healthy. S. intermedius was most commonly isolated (80%) followed by S. constellatus (12.6%) and S. anginosus (7.4%); 50.5% of cases were polymicrobial. Among polymicrobial cases, Staphylococcus aureus was most frequently isolated. All patients underwent surgical intervention. 8.4% of patients experienced persistent neurologic deficits. We observed a significant increase in disease incidence during the study period; in addition, the overall proportion of all intracranial infections caused by SAG increased.

CONCLUSIONS

Complications of otitis media and sinusitis caused by SAG are associated with substantial morbidity. These infections are becoming increasingly common at our center although the precise reason for this temporal trend is unclear.

Traditional culture methods fail to detect principle pathogens in necrotising soft tissue infection: a case report

OBJECTIVE

Necrotising soft tissue infections (NSTIs) progress rapidly and mortality remains high, ranging from 10% to 30%, representing a significant challenge for health professionals. Early accurate diagnosis is crucial because timely and aggressive surgical intervention remains the number one indicator for a better clinical outcome. Understanding the microbial background of NSTIs would aid early diagnosis.

PRESENTATION

We present a case of NSTI, in a seemingly healthy adult male, originating from a tooth abscess. The NSTI progressed rapidly, and eventually covered the patient's chest and abdominal skin and underlying soft tissue.

RESULTS

Traditional blood and tissue culture only found Group C Streptococcus where 16S sequencing detected abundant Prevotella spp., a more likely causal organisms of the NSTI. The use of antibiotics with the approriate anaerobe coverage, in combination with timely surgical intervention, contributed to the ultimate successful clinical outcome. Complete wound healing and successful graft was achieved within one month of diagnosis of the microbes present.

CONCLUSION

While surgical intervention remains the most important consideration in treatment of NSTI, correct identifcation of the microbial flora could also contribute to successful treatment.

Microbiology and clinical characteristics of viridans group streptococci in patients with cancer

This study assessed the microbiology, clinical syndromes, and outcomes of oncologic patients with viridans group streptococci isolated from blood cultures between January 1st, 2013 and December 31st, 2016 in a referral hospital in Mexico using the Bruker MALDI Biotyper. Antimicrobial sensitivity was determined using BD Phoenix 100 according to CLSI M100 standards. Clinical information was obtained from medical records and descriptive analysis was performed.

Forty-three patients were included, 22 females and 21 males, aged 42 ± 17 years. Twenty (46.5%) patients had hematological cancer and 23 (53.5%) a solid malignancy. The viridans group streptococci isolated were Streptococcus mitis, 20 (46.5%); Streptococcus anginosus, 14 (32.6%); Streptococcus sanguinis, 7 (16.3%); and Streptococcus salivarius, 2 (4.7%). The main risk factors were pyrimidine antagonist chemotherapy in 22 (51.2%) and neutropenia in 19 (44.2%) cases, respectively. Central line associated bloodstream infection was diagnosed in 18 (41.9%) cases. Septic shock occurred in 20.9% of patients, with an overall mortality of 18.6%. Only four S. mitis revealed penicillin-resistance.

Our results are similar to those of other series, identifying these bacteria as emerging pathogens with significant morbidity and mortality in oncologic patients. The MALDI-TOF system increased the rate of viridans group streptococci isolation in this population.

Aciduricity and acid tolerance mechanisms of Streptococcus anginosus

Although Streptococcus anginosus constitutes a proportion of the normal flora of the gastrointestinal and genital tracts, and the oral cavity, it has been reported that S. anginosus infection could be closely associated with abscesses at various body sites, infective endocarditis, and upper gastrointestinal cancers. The colonization in an acidic environment due to the aciduricity of S. anginosus could be the etiology of the systemic infection of the bacteria. To elucidate the aciduricity and acid tolerance mechanisms of the microbe, we examined the viability and growth of S. anginosus under acidic conditions. The viabilities of S. anginosus NCTC 10713 and Streptococcus mutans ATCC 25175 at pH 4.0 showed as being markedly higher than those of Streptococcus sanguinis ATCC 10556, Streptococcus gordonii ATCC 10558, and Streptococcus mitis ATCC 49456; however, the viability was partially inhibited by dicyclohexylcarbodiimide, an H⁺-ATPase inhibitor, suggesting that H⁺-ATPase could play a role in the viability of S. anginosus under acidic conditions. In addition, S. anginosus NCTC 10713 could grow at pH 5.0 and showed a marked arginine deiminase (ADI) activity, unlike its ΔarcA mutant, deficient in the gene encoding ADI, and other streptococcal species, which indicated that ADI could also be associated with aciduricity. These results suggest that S. anginosus has significant aciduric properties, which can be attributed to these enzyme activities.