A Rare Case of Lactobacillus acidophilus Presenting as Mitral Valve Bacterial Endocarditis

Infective Endocarditis by Lactobacillus Species-A Narrative Review

Bacteria of the genus Lactobacillus are microaerophilic or aerotolerant anaerobic Gram-positive non-spore-forming rods. They are considered essential members of the human gut microbiome; however, recent studies have revealed that these microorganisms are less predominant in the gut microbiome than initially thought. Lactobacillus spp. is mainly known for its use as a probiotic in foods and supplements to prevent and treat specific issues such as infectious diseases, irritable bowel syndrome, and diabetes mellitus. However, Lactobacillus spp. may occasionally cause infections such as bacteremia or infective endocarditis (IE). The present study aimed to review all cases of IE by Lactobacillus spp. and describe the epidemiology, microbiology, clinical characteristics, treatment, and outcomes of this infection by collecting relevant data from studies existing in Pubmed and Scopus until 28 September 2023. A total of 77 studies containing data for 82 patients were included. The median age was 56 years, and 69.6% were male. A prosthetic valve was present in 16% of patients, and 17.3% had previously been on probiotics. The aortic valve was the most commonly involved intracardiac site, followed by the mitral valve. Fever, embolic phenomena, sepsis, and heart failure were the most common clinical presentations. Aminoglycosides and penicillin were the most commonly used antimicrobials for definitive treatment. Surgery was performed in 53.7% of patients. Overall mortality was 17.1%. IE in prosthetic valves and presentation with shock were independently associated with overall mortality.

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.

Lactobacillus acidophilus-Induced Endocarditis and Associated Splenic Abscess

Lactobacillus acidophilus is a rod-shaped, Gram-positive bacterium generally found in the normal flora of the oropharynx, gastrointestinal, and genitourinary tracts. It is commonly known as nonpathogen in the human body. Endocarditis due to Lactobacillus is rarely encountered and associated with impaired immunity. Splenic abscess is also an uncommon infection that classically results from endocarditis or another source of hematogenous seeding. Here, we present the case of bioprosthetic aortic valve endocarditis and associated splenic abscess caused by Lactobacillus acidophilus. The source of the Lactobacillus bacteremia should be investigated because of the risk of life-threatening conditions. Most of the time, identifying Lactobacillus species is challenging and can cause a delay in diagnosis and timely treatment. Especially in patients who have significant underlying clinical conditions, physicians should consider Lactobacillus species as a causative microorganism.

Weighing in on the risks and benefits of probiotic use in HIV-infected and immunocompromised populations

Probiotics are used in the prophylaxis and treatment of several conditions, including irritable bowel syndrome, diarrhoea, necrotising enterocolitis (NEC) and colic in infants. Despite the long history of probiotic use in humans, there is still significant debate about their efficacy and safety, particularly in HIV-infected and immunocompromised individuals. Here, we reviewed the safety and adverse event (AE) reporting from clinical trials that have tested probiotics in at risk populations, including HIV-infected individuals, the terminally ill and elderly, and neonates. Our analysis suggests that the benefits of probiotic therapy outweigh their potential risks in HIV-infected populations, and in the treatment of colic and NEC in low birth weight or premature neonates. Most case reports of severe AEs were in the elderly and terminally ill, or in those with additional severe medical conditions. We conclude that probiotic use, as adjunctive treatment, is effective and safe in the majority of patients including HIV-infected individuals, although special care should be taken in individuals with extreme immunosuppression and severe medical conditions in all ages.

Infectious endocarditis caused by Lactobacillus acidophilus in a patient with mistreated dental caries

We present a rare case of infectious endocarditis caused by Lactobacillus acidophilus in a patient on long-term steroid use for autoimmune hepatitis. In vitro susceptibility-guided antibiotics with benzylpenicillin plus clindamycin and successive mitral annuloplasty resulted in a favorable outcome. Infectious endocarditis was suspected to be a complication of mistreated periodontal infection. Maintenance of oral hygiene is important in immunocompromised patients.

Safety of probiotics: translocation and infection

The long history of safety has contributed to the acceptance of probiotics as a safe food adjunct. Consequently, many probiotic products and their applications have been granted GRAS (generally regarded as safe) status. However, this classification has been frequently generalized for all probiotic strains regardless of their application. Cases of probiotics from the genera Lactobacillus, Leuconostoc, Pediococcus, Enterococcus, and Bifidobacterium have been isolated from infection sites, leading to the postulation that these probiotics can translocate. Probiotic translocation is difficult to induce in healthy humans, and even if it does occur, detrimental effects are rare. Despite this, various reports have documented health-damaging effects of probiotic translocation in immunocompromised patients. Due to probiotics' high degree of safety and their morphological confusion with other pathogenic bacteria, they are often overlooked as contaminants and are least suspected as pathogens. However, the antibiotic resistance of some strains has increased the complexity of their eradication. Probiotic translocation and infection deserve further investigation and should become a facet of safety assessment so the negative effects of probiotics do not outweigh the benefits.

Infective endocarditis caused by lactobacillus

Lactobacillus (LB) is a gram-positive rod-shaped bacterium that inhabits the oral cavity, gastrointestinal tract, vagina and nasal cavity. Although LB plays a role in the prevention of infections caused by pathogenic bacteria, it causes some critical infectious diseases such as infective endocarditis (IE). IE due to LB is rare; however, early diagnosis and early treatment are important because of its high mortality rate. We report the onset of IE after otologic treatment in a heavy drinker of alcohol, the second case of IE due to LB in Japan.