Infectivity of Lactobacillus rhamnosus and Lactobacillus paracasei isolates in a rat model of experimental endocarditis

Lactobacillus endocarditis: a case report in France and literature review

Lactobacilli are commensal bacteria in the normal flora of the oral cavity, gastrointestinal and genital tract. However, few cases of lactobacilli-induced bacteremia or endocarditis have been reported, particularly in immunocompromised patients. We reported a rare case of a 57-year-old man with a Lactobacillus rhamnosus endocarditis without immunodeficiency in his medical history. He received a dental scaling one year before. Clinical presentation included weight loss, heart murmur, ankle arthritis and splinter hemorrhage. Echocardiography showed a mitral prolapse and a 16 mm vegetation associated with a valvular perforation. All blood cultures were positive for Lactobacillus rhamnosus. Antibacterial regimen with amoxicillin and gentamicin led to recovery without surgery. We present a literature review of the lactobacillary endocarditis cases published since 1992. Valvulopathy, dental or invasive procedures and probiotics use were the main underlying conditions, in contrary to immunodeficiency. Diagnosis of lactobacillary endocarditis should be more considered and a treatment with penicillin and aminoglycoside should be promptly introduced in life-threatening cases.

Prosthetic Aortic Valve Endocarditis in a Patient With Birt-Hogg-Dube Syndrome due to Lactobacillus paracasei

Various causative organisms and predisposing factors were implicated in the pathogenic process behind prosthetic valve endocarditis. Lactobacillus paracasei, a classic constituent of probiotics, rarely causes infections in humans and was reported only in few case reports. The use of probiotics was hypothesized to be a risk factor for these infections; however, no causative relationship could be drawn. We describe a 75-year-old woman with history of Birt-Hogg-Dube syndrome and bioprosthetic aortic valve replacement who presented with worsening dyspnea was found to have Lactobacillus paracasei bacteremia and evidence of bacterial vegetations noted on transesophageal echocardiography (TEE) along with evidence of severe aortic insufficiency. Based on antibiotics sensitivity profile, she was treated with penicillin and gentamycin, which resulted in bacterial clearance on repeat blood cultures, and the patient was transferred to a different facility to undergo replacement of the prosthetic aortic valve. Although Lactobacillus paracasei is rarely involved in human infections, it should be suspected in patients with underlying structural heart/valvular disease, recent antibiotic exposure or recent probiotic use who are presenting with evidence of infective endocarditis. Combination antibiotics including beta lactams, aminoglycosides and clindamycin are suggested treatment of choice for this organism.

Lactobacillus paracasei endocarditis of bioprosthetic aortic valve presenting with recurrent embolic strokes

Introduction

Lactobacillus prosthetic valve endocarditis is a rare infection caused by Lactobacillus bacteria. This bacterium is found in the normal flora of the human mouth, gastrointestinal tract and female genital tract. While there have been isolated cases of Lactobacillus bacteraemia and endocarditis, the infections are associated with comorbidities, immune deficiency, dental manipulation procedures and other medical history. This case of bioprosthetic valve endocarditis caused by Lactobacillus paracasei is unusual, as the patient was immune-competent and treated with pre-procedural antibiotics.

Case

We present a case of a 65-year-old male who underwent a dental extraction. He presented after 3 months of fever, chills and fatigue. On initial presentation, blood cultures were positive for alpha-haemolytic streptococcus bacteraemia. He was treated with IV penicillin and underwent aortic valve replacement with a bioprosthetic valve and excision of the mitral vegetation with repair of the mitral valve. Two years later, he had a tooth extraction after being treated properly with antibiotics. Three months later he presented with difficulty speaking, left leg weakness and increased drooling. All testing was normal. Three months later he presented with left side lower extremity weakness and expressive aphasia. He was diagnosed with bioprosthetic aortic valve endocarditis and was treated with IV penicillin and gentamicin for 6 weeks and then switched to oral penicillin. He remained stable.

Conclusions

L. paracasei can potentially be a cause of complicated endocarditis in patients with prosthetic heart valves undergoing dental procedures. Timely culture-guided antibiotic therapy is critical and may obviate the need for valve surgery.

Probiotics and infective endocarditis in patients with hereditary hemorrhagic telangiectasia: a clinical case and a review of the literature

Background

In the last decades, probiotics have been widely used as food supplements because of their putative beneficial health effects. They are generally considered safe but rare reports of serious infections caused by bacteria included in the definition of probiotics raise concerns on their potential pathogenic role in patients with particular predisposing factors. Patients with hereditary hemorrhagic telangiectasia (HHT) are exposed to infections because of telangiectasias and arteriovenous malformations (AVMs). We describe what is, to our knowledge, the first case of infective endocarditis (IE) caused by Lactobacillus rhamnosus in a patient with HHT. A systematic review of the relevant medical literature is presented.

Case presentation

A patient with HHT and an aortic bioprosthesis was admitted because of prolonged fever not responding to antibiotics. The patient had a history of repeated serious infections with hospitalizations and prolonged use of antibiotics, and used to assume large amounts of different commercial products containing probiotics. Weeks before the onset of symptoms the patient had been treated with nasal packings and with surgical closure of a nasal bleeding site because of recurrent epistaxis. A diagnosis of IE of the aortic bioprosthesis was made. All blood coltures were positive for L. rhamnosus. The patients responded to a cycle of 6 weeks of amoxicillin/clavulanate plus gentamicin. A systematic review of IE linked to consumption of probiotics, and of infective endocarditis in patients with HHT was conducted. 10 cases of IE linked to probiotics consumption and 6 cases of IE in patients with HHT were found.

Conclusions

Consumption of probiotics can pose a risk of serious infections in patients with particular predisposing factors. Patients with HHT can be considered at risk because of their predisposition to infections. Prophylaxis with antibiotics before nasal packings in patients with HHT can be considered.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-2956-5) contains supplementary material, which is available to authorized users.

Probiotics in the treatment of periodontal disease: A systematic review

Over the years, probiotics have been used in the treatment of a variety of diseases. The use of probiotics in the treatment of periodontal disease has caught on over the last decade or so. This review was performed to determine whether administration of probiotics produced a lasting clinical benefit in the treatment of periodontal disease. A MEDLINE, Cochrane database and a hand search was performed on human randomized placebo controlled trials using probiotics in the treatment of periodontal disease. A total of thirteen papers which addressed the question of the use of probiotics in the treatment of periodontal disease were retrieved. Most of the studies reviewed showed only a short term benefit with regards to reduction in gingival inflammation and probing depth reduction. Lasting clinical benefits were not seen in any of the studies. At least four different combinations and strains of probiotics have been used in the studies. There also existed significant heterogeneity in the methodology of the studies reviewed. It was concluded that current regimens of probiotics in the treatment of periodontal disease produce only short-term clinical and microbiologic benefits.

The controversial nature of the Weissella genus: technological and functional aspects versus whole genome analysis-based pathogenic potential for their application in food and health

Despite the use of several Weissella (W.) strains for biotechnological and probiotic purposes, certain species of this genus were found to act as opportunistic pathogens, while strains of W. ceti were recognized to be pathogenic for farmed rainbow trout. Herein, we investigated the pathogenic potential of weissellas based on in silico analyses of the 13 whole genome sequences available to date in the NCBI database. Our screening allowed us to find several virulence determinants such as collagen adhesins, aggregation substances, mucus-binding proteins, and hemolysins in some species. Moreover, we detected several antibiotic resistance-encoding genes, whose presence could increase the potential pathogenicity of some strains, but should not be regarded as an excluding trait for beneficial weissellas, as long as these genes are not present on mobile genetic elements. Thus, selection of weissellas intended to be used as starters or for biotechnological or probiotic purposes should be investigated regarding their safety aspects on a strain to strain basis, preferably also by genome sequencing, since nucleotide sequence heterogeneity in virulence and antibiotic resistance genes makes PCR-based screening unreliable for safety assessments. In this sense, the application of W. confusa and W. cibaria strains as starter cultures or as probiotics should be approached with caution, by carefully selecting strains that lack pathogenic potential.

Screening of Probiotic Candidates in Human Oral Bacteria for the Prevention of Dental Disease

The oral cavity in healthy subjects has a well-balanced microbiota that consists of more than 700 species. However, a disturbance of this balance, with an increase of harmful microbes and a decrease of beneficial microbes, causes oral disorders such as periodontal disease or dental caries. Nowadays, probiotics are expected to confer oral health benefits by modulating the oral microbiota. This study screened new probiotic candidates with potential oral health benefits and no harmful effects on the oral cavity. We screened 14 lactobacillus strains and 36 streptococcus strains out of 896 oral isolates derived from healthy subjects. These bacteria did not produce volatile sulfur compounds or water-insoluble glucan, had higher antibacterial activity against periodontal bacteria, and had higher adherence activity to oral epithelial cells or salivary-coated hydroxyapatite in vitro. We then evaluated the risk of primary cariogenicity and infective endocarditis of the selected oral isolates. As a result, Lactobacillus crispatus YIT 12319, Lactobacillus fermentum YIT 12320, Lactobacillus gasseri YIT 12321, and Streptococcus mitis YIT 12322 were selected because they showed no cariogenic potential in an artificial mouth system and a lower risk of experimental infective endocarditis in a rat model. These candidates are expected as new probiotics with potential oral health benefits and no adverse effects on general health.

Splenic abscess caused by Lactobacillus paracasei

Splenic abscess is relatively uncommon. Infections caused by lactobacilli, which are usually one of the constituents of normal flora of human gut and vagina, are also very uncommon. Here we report a case of splenic abscess caused by Lactobacillus paracasei. We performed a literature review for this rare entity. Immunocompromised status of the patient, who had uncontrolled diabetes, could have contributed to the pathogenesis of this rare disease.

Safety assessment of probiotics for human use

The safety of probiotics is tied to their intended use, which includes consideration of potential vulnerability of the consumer or patient, dose and duration of consumption, and both the manner and frequency of administration. Unique to probiotics is that they are alive when administered, and unlike other food or drug ingredients, possess the potential for infectivity or in situ toxin production. Since numerous types of microbes are used as probiotics, safety is also intricately tied to the nature of the specific microbe being used. The presence of transferable antibiotic resistance genes, which comprises a theoretical risk of transfer to a less innocuous member of the gut microbial community, must also be considered. Genetic stability of the probiotic over time, deleterious metabolic activities, and the potential for pathogenicity or toxicogenicity must be assessed depending on the characteristics of the genus and species of the microbe being used. Immunological effects must be considered, especially in certain vulnerable populations, including infants with undeveloped immune function. A few reports about negative probiotic effects have surfaced, the significance of which would be better understood with more complete understanding of the mechanisms of probiotic interaction with the host and colonizing microbes. Use of readily available and low cost genomic sequencing technologies to assure the absence of genes of concern is advisable for candidate probiotic strains. The field of probiotic safety is characterized by the scarcity of studies specifically designed to assess safety contrasted with the long history of safe use of many of these microbes in foods.