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

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.

Emerging pre-clinical safety assessments for potential probiotic strains: a review

Probiotics are amply studied and applied dietary supplements of greater consumer acceptance. Nevertheless, the emerging evidence on probiotics-mediated potential risks, especially among immunocompromised individuals, necessitates careful and in-depth safety studies. The traditional probiotic safety evaluation methods investigate targeted phenotypic traits, such as virulence factors and antibiotic resistance. However, the rapid innovation in omics technologies has offered an impactful means to ultimately sequence and unknot safety-related genes or their gene products at preliminary levels. Further validating the genome features using an array of phenotypic tests would provide an absolute realization of gene expression dynamics. For safety studies in animal models, the in vivo toxicity evaluation guidelines of chemicals proposed by the Organization for Economic Co-operation and Development (OECD) have been meticulously adopted in probiotic research. Future research should also focus on coupling genome-scale safety analysis and establishing a link to its transcriptome, proteome, or metabolome for a fine selection of safe probiotic strains. Considering the studies published over the years, it can be inferred that the safety of probiotics is strain-host-dose-specific. Taken together, an amalgamation of in silico, in vitro, and in vivo approaches are necessary for a fine scale selection of risk-free probiotic strain for use in human applications.

Lactobacilli Infection Case Reports in the Last Three Years and Safety Implications

Lactobacilli constitute the dominant microbiota in many fermented foods and comprise widely used probiotics. However, these bacteria cause rare infections mostly in diabetic and immunocompromised subjects in presence of risk factors such as prosthetic hearth valves and dental procedures or caries. The scope of this survey was re-assessing the pathogenic potential of lactobacilli based on the infection case reports published in the last three years. In 2019, 2020, and 2021, total of 17, 15, and 16 cases, respectively, including endocarditis, bacteremia, and other infections, were reported. These annual numbers are higher than those observed previously. Lacticaseibacillus rhamnosus (13 cases), comprising strain GG (ATCC 53103) with established applications in healthcare, L. paracasei (7 cases), Lactobacillus acidophilus (5 cases), L. jensenii (5 cases), Lactiplantibacillus plantarum (3 cases), L. paraplantarum, L. delbrueckii subsp. delbrueckii, L. gasseri, L. paragasseri, Limosilactobacillus fermentum, and L. reuteri (1 case each) were involved. Virulence characterization of two strains that caused infections, a derivative of L. rhamnosus GG and L. paracasei LP10266, indicated that increased biofilm-forming capacity favors pathogenicity and it is determined by variable genetic traits. This survey highlights that the strains of lactobacilli that cause infections are little characterized genetically. Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are administered to vulnerable individuals.

Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 12: suitability of taxonomic units notified to EFSA until March 2020

The qualified presumption of safety (QPS) was developed to provide a generic safety evaluation for biological agents to support EFSA's Scientific Panels. It is based on an assessment of the taxonomic identity, the body of knowledge, safety concerns and antimicrobial resistance. Safety concerns identified for a taxonomic unit (TU) are where possible to be confirmed at strain or product level, reflected by 'qualifications'. No new information was found that would change the previously recommended QPS TUs of the 39 microorganisms notified to EFSA between October 2019 and March 2020, 33 were excluded, including five filamentous fungi, five Escherichia coli, two Enterococcus faecium, two Streptomyces spp. and 19 TUs already evaluated. Six TUs were evaluated. Akkermansia muciniphila was not recommended for QPS status due to safety concerns. Clostridium butyricum was not recommended because some strains contain pathogenicity factors. This TU was excluded for further QPS evaluation. Galdieria sulphuraria and Pseudomonas chlororaphis were also rejected due to a lack of body of knowledge. The QPS status of Corynebacterium ammoniagenes (with the qualification 'for production purposes only') and of Komagataella pastoris (with the qualification 'for enzyme production') was confirmed. In relation to the taxonomic revision of the Lactobacillus genus, previously designated Lactobacillus species will be reassigned to the new species and both the old and new names will be retained in the QPS list.