Prevotella bivia as an unusual cause of endocarditis

Glucose-lowering effects of a synbiotic combination containing Pediococcus acidilactici in C. elegans and mice

AIMS/HYPOTHESIS

Modulation of gut microbiota has emerged as a promising strategy to treat or prevent the development of different metabolic diseases, including type 2 diabetes and obesity. Previous data from our group suggest that the strain Pediococcus acidilactici CECT9879 (pA1c) could be an effective probiotic for regulating glucose metabolism. Hence, the objectives of this study were to verify the effectiveness of pA1c on glycaemic regulation in diet-induced obese mice and to evaluate whether the combination of pA1c with other normoglycaemic ingredients, such as chromium picolinate (PC) and oat β-glucans (BGC), could increase the efficacy of this probiotic on the regulation of glucose and lipid metabolism.

METHODS

Caenorhabditis elegans was used as a screening model to describe the potential synbiotic activities, together with the underlying mechanisms of action. In addition, 4-week-old male C57BL/6J mice were fed with a high-fat/high-sucrose diet (HFS) for 6 weeks to induce hyperglycaemia and obesity. Mice were then divided into eight groups (n=12 mice/group) according to dietary supplementation: control-diet group; HFS group; pA1c group (1010 colony-forming units/day); PC; BGC; pA1c+PC+BGC; pA1c+PC; and pA1c+BGC. Supplementations were maintained for 10 weeks. Fasting blood glucose was determined and an IPGTT was performed prior to euthanasia. Fat depots, liver and other organs were weighed, and serum biochemical variables were analysed. Gene expression analyses were conducted by real-time quantitative PCR. Sequencing of the V3-V4 region of the 16S rRNA gene from faecal samples of each group was performed, and differential abundance for family, genera and species was analysed by ALDEx2R package.

RESULTS

Supplementation with the synbiotic (pA1c+PC+BGC) counteracted the effect of the high glucose by modulating the insulin-IGF-1 signalling pathway in C. elegans, through the reversal of the glucose nuclear localisation of daf-16. In diet-induced obese mice, all groups supplemented with the probiotic significantly ameliorated glucose tolerance after an IPGTT, demonstrating the glycaemia-regulating effect of pA1c. Further, mice supplemented with pA1c+PC+BGC exhibited lower fasting blood glucose, a reduced proportion of visceral adiposity and a higher proportion of muscle tissue, together with an improvement in the brown adipose tissue in comparison with the HFS group. Besides, the effect of the HFS diet on steatosis and liver damage was normalised by the synbiotic. Gene expression analyses demonstrated that the synbiotic activity was mediated not only by modulation of the insulin-IGF-1 signalling pathway, through the overexpression of GLUT-1 and GLUT-4 mediators, but also by a decreased expression of proinflammatory cytokines such as monocyte chemotactic protein-1. 16S metagenomics demonstrated that the synbiotic combinations allowed an increase in the concentration of P. acidilactici, together with improvements in the intestinal microbiota such as a reduction in Prevotella and an increase in Akkermansia muciniphila.

CONCLUSIONS/INTERPRETATION

Our data suggest that the combination of pA1c with PC and BGC could be a potential synbiotic for blood glucose regulation and may help to fight insulin resistance, diabetes and obesity.

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INTRODUCTION

Prevotella species (i. e. P. intermedia, P. nigrescens, P. pallens, P. oris) are usually responsible for abscesses of head and neck spaces after dental procedures. P. intermedia - related infective endocarditis has never been reported.

CASE REPORT

A 22-year-old man, with a history of aortic valve replacement 6 years ago, presented with fever and persistent retrosternal chest pain. An empirical antibiotic therapy was started on (cefotaxime, 2gx3 - gentamicin, 5mg/kilo). Five blood cultures were positive at Prevotella Intermedia. Metronidazole was introduced (500mg X 3 by day).The oro-pharyngeal spaces were normal. The evolution was marked by a hypotension, a third degree atrio-ventricular block, and a rapidly growing aortic root abscess complicated this case of Prevotella Intermedia infective endocarditis (IE). Aortic valve redux surgery was performed at day 5 of admission. Post-operative course was unremarkable.

CONCLUSION

This first reported case of Prevotella Intermedia IE presented suggestive features of anaerobic IE as the patient developed both aortic-ring abscess, third degree atrio-ventricular block and hypotension.

Anaerobes in cardiac infections: A decade experience from the tertiary care center

PURPOSE

Anaerobic infections are common yet life-threatening. They are being recovered from all sites of the body, including the cardiovascular system. This study was aimed to determine the retrospective analysis on the isolation of anaerobes in cardiovascular samples received for a decade-long duration. It helps in knowing the frequency of isolation of anaerobic causes of cardiovascular infection.

METHODS

All cardiovascular samples from the department of Cardio-thoracic vascular surgery from January 2010 to December 2020 were studied.

RESULTS

Of 601 samples received, predominant samples were vegetations and valvular tissues of 258, followed by 98 samples of pericardial tissues, 92 samples of embolus, 90 samples of blood and post-operative collections, and 63 excised aneurysms and vascular grafts. Of the total, 15 samples grew anaerobes where Clostridium species were the predominant isolates. Clostridioides difficile was isolated in 2 samples.

CONCLUSIONS

Anaerobes in cardiovascular samples are uncommon yet form a significant cause of morbidity and mortality. Most infections are from the contiguous spread, penetrating trauma, and hematogenous causing endocarditis or valvular infections. These conditions and samples form the seat of infectious focus and clinical suspicion towards the anaerobic cause of these conditions, especially in conventional routine culture-negative samples. Timely diagnosis of anaerobic infections plays a vital role in the good prognostic outcome of patients undergoing cardiothoracic and vascular surgery.

Purulent Proctitis Caused by Prevotella bivia in a Homosexual Male

A 32-year-old homosexual male presented with suprapubic pain. Computed tomography showed rectal wall thickening. Flexible sigmoidoscopy showed small pockets of pus that were opened with mucosal biopsies, and additional pus was diffusely expressed from the rectal wall by applying blunt pressure with the biopsy forceps. Cultures from the pus grew Prevotella bivia. Symptoms resolved after treatment with doxycycline and metronidazole. Proctitis due to P. bivia was not previously reported.

Clostridium hathewayi bacteraemia and surgical site infection after uterine myomectomy

A 42-year-old woman with uterine fibroids underwent myomectomy. She developed postoperative sepsis and bloodstream infection with Clostridium hathewayi secondary to an infected haematoma. The patient was readmitted after failure of oral antibiotic therapy and underwent intrauterine drainage followed by prolonged parenteral antibiotic therapy. The patient was followed for 1 year and did not have any relapse of infection.

Empyema caused by Prevotella bivia complicating an unusual case of spontaneous chylothorax

Spontaneous chylothorax is rare in adults. We present an unusual case that was complicated by Prevotella bivia empyema. Full recovery was achieved with chest tube drainage and prompt treatment with intravenous clindamycin.

Abdominal wall phlebitis due to Prevotella bivia following renal transplantation in a patient with an occluded inferior vena cava

Pre-existing occlusion of the inferior vena cava may complicate renal transplantation. Suppurative abdominal wall phlebitis following renal transplantation was diagnosed in a patient with pre-existing thrombosis of the inferior vena cava of unknown cause. The phlebitis developed in the subcutaneous collateral veins of the abdominal wall contra-laterally to the renal transplant. Cultures from abdominal wall micro-abscesses yielded Prevotella bivia as the causative agent. This complication has not been described before in the context of renal transplantation. The pathogenesis and management of this serious complication are discussed in this paper.

Chest wall abscess due to Prevotella bivia

Prevotella bivia is associated with pelvic inflammatory disease. A 77-year-old man developed a rapidly growing chest wall abscess due to P. bivia within days. He underwent surgical resection of the infected area; his postoperative course was uneventful. This is the first case of chest wall abscess due to P. bivia infection. Its correct diagnosis cannot be underestimated because fulminant infections can occur in aged or immunocompromised patients if treated incorrectly. Prompt, appropriate surgical management, and antibiotic therapy affect treatment outcome.

Paronychia due to Prevotella bivia that resulted in amputation: fast and correct bacteriological diagnosis is crucial

Prevotella bivia is mainly associated with endometritis. The case of a patient with paronychia in a thumb due to P. bivia resulting in osteitis and amputation is reported. The species was not acknowledged in the first bacterial culture 2 weeks before surgery.

Antibiotic prophylaxis: problems in paradise

The age of antibiotic prophylaxis may be receding into its twilight years because the assumption upon which it was based has not proved generally true. Although antibiotics treat infections, limited benefit has been demonstrated in preventing infections. These are two entirely different biologic entities, a distinction which appears to have gone unappreciated by many for more than 50 years. If the principles of antibiotic prophylaxis established more than 40 years ago had been assiduously followed, many of its abuses could have been avoided. This may not have stopped our legal colleagues, but it would have been worth an effort on behalf of our patients. It is likely that the massive overuse of antibiotics as litigation prevention has contributed to the global epidemic of antibiotic-resistant micro-organisms and an unknown number of serious adverse effects to the antibiotics themselves. Even with this abuse, much money has still flowed from defendant to plaintiff. Substantial data exist that antibiotics do not prevent bacteremias. The absolute risk rate for bacterial endocarditis after dental treatment even in at-risk patients is very low. Antibiotic prophylaxis for surgical infections requires specific dosing schedules (perioperative surgical prophylaxis) to be successful. Hopefully the difficulties presented herein regarding antibiotic prophylaxis will lead to their more enlightened use in the future.

Advances in medical and antibiotic management of infective endocarditis

Infective endocarditis remains a serious medical problem despite advancements in laboratory detection, echocardiographic techniques, and newer antibiotic agents. This article summarizes the microbial agents in infective endocarditis, in addition to developments in medical and antibiotic management.