Eggerthella lenta bloodstream infections: two cases and review of the literature

Clinical and microbiological characteristics of Eggerthella lenta causing bacteremia

Eggerthella lenta is an obligate anaerobic, Gram-positive bacilli, belonging to the human microbiota of gastrointestinal and female reproductive tracts, oral cavity and prostate gland. In this article, we aim to describe clinical and microbiological characteristics of seven E. lenta strains causing bacteremia. We conducted a descriptive retrospective study including all E. lenta strains causing bacteremia, from February 2019 to August 2023 at the Basurto University Hospital. Seven patients were included in the study with a mean age of 72.7 years. Six patients presented risk factors associated with bacterial infections. All patients were admitted to the hospital because of suspicious of bloodstream infection associated with abdominal symptoms for intravenous antibiotic treatment. Four E. lenta isolates were resistant to penicillin, while all isolates presented high MICs to piperacillin/tazobactam and low MICs to amoxicillin/clavulanic acid. All patients recovered without no complications.

Drug-microbiota interactions: an emerging priority for precision medicine

Individual variability in drug response (IVDR) can be a major cause of adverse drug reactions (ADRs) and prolonged therapy, resulting in a substantial health and economic burden. Despite extensive research in pharmacogenomics regarding the impact of individual genetic background on pharmacokinetics (PK) and pharmacodynamics (PD), genetic diversity explains only a limited proportion of IVDR. The role of gut microbiota, also known as the second genome, and its metabolites in modulating therapeutic outcomes in human diseases have been highlighted by recent studies. Consequently, the burgeoning field of pharmacomicrobiomics aims to explore the correlation between microbiota variation and IVDR or ADRs. This review presents an up-to-date overview of the intricate interactions between gut microbiota and classical therapeutic agents for human systemic diseases, including cancer, cardiovascular diseases (CVDs), endocrine diseases, and others. We summarise how microbiota, directly and indirectly, modify the absorption, distribution, metabolism, and excretion (ADME) of drugs. Conversely, drugs can also modulate the composition and function of gut microbiota, leading to changes in microbial metabolism and immune response. We also discuss the practical challenges, strategies, and opportunities in this field, emphasizing the critical need to develop an innovative approach to multi-omics, integrate various data types, including human and microbiota genomic data, as well as translate lab data into clinical practice. To sum up, pharmacomicrobiomics represents a promising avenue to address IVDR and improve patient outcomes, and further research in this field is imperative to unlock its full potential for precision medicine.

Genetic manipulation of the human gut bacterium Eggerthella lenta reveals a widespread family of transcriptional regulators

Eggerthella lenta is a prevalent human gut Actinobacterium implicated in drug, dietary phytochemical, and bile acid metabolism and associated with multiple human diseases. No genetic tools are currently available for the direct manipulation of E. lenta. Here, we construct shuttle vectors and develop methods to transform E. lenta and other Coriobacteriia. With these tools, we characterize endogenous E. lenta constitutive and inducible promoters using a reporter system and construct inducible expression systems, enabling tunable gene regulation. We also achieve genome editing by harnessing an endogenous type I-C CRISPR-Cas system. Using these tools to perform genetic knockout and complementation, we dissect the functions of regulatory proteins and enzymes involved in catechol metabolism, revealing a previously unappreciated family of membrane-spanning LuxR-type transcriptional regulators. Finally, we employ our genetic toolbox to study the effects of E. lenta genes on mammalian host biology. By greatly expanding our ability to study and engineer gut Coriobacteriia, these tools will reveal mechanistic details of host-microbe interactions and provide a roadmap for genetic manipulation of other understudied human gut bacteria.

Polymicrobial anaerobic sepsis due to Bacteroides fragilis, Eggerthella lenta, Ruminoccocus gnavus, and Bilophila wadsworthia in a patient with myeloproliferative neoplasm

We report a rare case of polymicrobial anaerobic bacteremia caused by four different gut anaerobes: Bacteroides fragilis, Eggerthella lenta, Bilophila wadsworthia, and Ruminococcus gnavus. Early initiation of appropriate therapy and species identification with matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) resulted in full recovery from the infection. Our case highlights the clinical significance of polymicrobial cultures and the importance of performing anaerobic cultures for blood specimens to ensure proper identification and treatment.

Modifying the Microbiome as a Potential Mechanism of Photobiomodulation: A Case Report

Objective: The objective of this case study was to elucidate the effect of photobiomodulation (PBM) on the microbiome. Background: The gut microbiome has been identified as a key component of health, with gut dysbiosis, characterized by decreased microbial diversity and an altered microbial composition, being recognized as instrumental in many diseases and disorders. Previous research has suggested that the gut microbiome can be favorably altered in animal models using PBM. Materials and methods: The participant had their microbiome tested on nine occasions, three times before any treatment, three times after radiotherapy and commencement of immunotherapy for breast cancer, and three times after PBM treatment. The PBM treatment consisted of infrared laser treatment (904 nm; 700 Hz pulse frequency, 861.3 total joules) to the abdomen three times per week for 11 weeks. Results: The microbiome of the participant showed significant changes in diversity after PBM treatment, but not after cancer therapy, with an increase in the number of known beneficial bacteria (Akkermansia, Faecalibacterium, and Roseburia) and decrease in the number of potentially pathogenic genera. Conclusions: The results suggested the possibility that PBM may alter the microbiome and thus it represents a therapeutic avenue for chronic diseases with otherwise limited treatment options.

Alterations of fecal antibiotic resistome in COVID-19 patients after empirical antibiotic exposure

As the COVID-19 pandemic spread globally, the consumption of antibiotics increased. However, no studies exist evaluating the effect of antibiotics use on the antibiotic resistance of intestinal flora in COVID-19 patients during the pandemic. To explore this issue, we collected 15 metagenomic data of fecal samples from healthy controls (HCs) with no use history of antibiotics, 23 metagenomic data of fecal samples from COVID-19 patients who received empirical antibiotics [COVID-19 (abx+)], 18 metagenomic data of fecal samples from antibiotics-naïve COVID-19 patients [COVID-19 (abx-)], and six metagenomic data of fecal samples from patients with community-acquired pneumonia [PC (abx+)] from the Sequence Read Archive database. A total of 513 antibiotic-resistant gene (ARG) subtypes of 18 ARG types were found. Antibiotic treatment resulted in a significant increase in the abundance of ARGs in intestinal flora of COVID-19 patients and markedly altered the composition of ARG profiles. Grouped comparisons of pairs of Bray-Curtis dissimilarity values demonstrated that the dissimilarity of the HC versus the COVID-19 (abx+) group was significantly higher than the dissimilarity of the HC versus the COVID-19 (abx-) group. The mexF, mexD, OXA_209, major facilitator superfamily transporter, and EmrB_QacA family major facilitator transporter genes were the discriminative ARG subtypes for the COVID-19 (abx+) group. IS621, qacEdelta, transposase, and ISCR were significantly increased in COVID-19 (abx+) group; they greatly contributed toward explaining variation in the relative abundance of ARG types. Overall, our data provide important insights into the effect of antibiotics use on the antibiotic resistance of COVID-19 patients during the COVID-19 epidemic.

Cardiovascular Diseases and Pharmacomicrobiomics: A Perspective on Possible Treatment Relevance

Cardiovascular diseases (CVDs), the most common cause of mortality in rich countries, include a wide variety of pathologies of the heart muscle and vascular system that compromise the proper functioning of the heart. Most of the risk factors for cardiovascular diseases are well-known: lipid disorders, high serum LDL cholesterol, hypertension, smoking, obesity, diabetes, male sex and physical inactivity. Currently, much evidence shows that: (i) the human microbiota plays a crucial role in maintaining the organism’s healthy status; and (ii) a link exists between microbiota and cardiovascular function that, if dysregulated, could potentially correlate with CVDs. This scenario led the scientific community to carefully analyze the role of the microbiota in response to drugs, considering this the right path to improve the effectiveness of disease treatment. In this review, we examine heart diseases and highlight how the microbiota actually plays a preponderant role in their development. Finally, we investigate pharmacomicrobiomics—a new interesting field—and the microbiota’s role in modulating the response to drugs, to improve their effectiveness by making their action targeted, focusing particular attention on cardiovascular diseases and on innovative potential treatments.

Eggerthella lenta bacteremia successfully treated with ceftizoxime: case report and review of the literature

Eggerthella lenta is a normal human microflora that is anaerobic, non-sporulating, and Gram positive. However, an increasing number of studies have shown that it could also be an important pathogen for humans, even causing life-threatening infection under certain conditions. However, understanding its pathogenic mechanism and treatment options still need to be improved; more clinical data are needed to explore it further. In this article, we report a case of ceftizoxime-cured E. lenta bacteremia and review the recent literature to provide more clinical data for the diagnosis of E. lenta bacteremia. Our report suggests that the frequency of E. lenta bacteremia is increased in patients with hematologic or solid organ cancer, diabetes mellitus and also in those with appendicitis.

Eggerthella lenta Bacteremia in a Middle-Aged Healthy Man with Acute Hepatic Abscess: Case Report and Literature Review, 1970-2020

Eggerthella lenta (E. lenta) is a rare but significant human emerging pathogen. Infections caused by it are rare and little-known, both on clinical and therapeutical aspects, in spite of new emergence of bacteria isolation and identification techniques. In this article, we report a case involving a previously healthy 52-year-old man suffering from a newly diagnosed hepatic abscess who developed E. lenta bacteremia, which was treated successfully using empirical therapy with ertapenem and teicoplanin. To the best of our knowledge, this is the first documented report of E. lenta bacteremia related specifically to liver abscess. Cases related to this bacterial species are infrequent and sporadic; thus, we reviewed English literature on E. lenta infection in PubMed/MEDLINE in the last 50 years. A total of 31 sporadic cases were identified. The majority of patients were male (71%), had an average age of 54.3 years and presented predisposing conditions, such as digestive system trouble (45.2%), immunocompromised state (25.8%) or risk factors (22.6%). Two of the cases had more than one predisposing factors. Fever was common (93.5%). Average days to diagnosis of them were 6.8 days. MALDI-TOF MS is emerging as a fast and useful tool in the identification of it. Teicoplanin, vancomycin, amoxicillin-clavulanate, metronidazole, clindamycin, cefoxitin, chloramphenicol, and carbapenems appear to be the most used antibiotic treatment options. The purpose of this review is to increase awareness about the clinical infections caused by E. lenta.

Identification of mucin degraders of the human gut microbiota

Mucins are large glycoproteins consisting of approximately 80% of hetero-oligosaccharides. Gut mucin degraders of healthy subjects were investigated, through a culture dependent and independent approach. The faeces of five healthy adults were subjected to three steps of anaerobic enrichment in a medium with sole mucins as carbon and nitrogen sources. The bacterial community was compared before and after the enrichment by 16S rRNA gene profiling. Bacteria capable of fermenting sugars, such as Anaerotruncus, Holdemania, and Enterococcaceae likely took advantage of the carbohydrate chains. Escherichia coli and Enterobacteriaceae, Peptococcales, the Coriobacteriale Eggerthella, and a variety of Clostridia such as Oscillospiraceae, Anaerotruncus, and Lachnoclostridium, significantly increased and likely participated to the degradation of the protein backbone of mucin. The affinity of E. coli and Enterobacteriaceae for mucin may facilitate the access to the gut mucosa, promoting gut barrier damage and triggering systemic inflammatory responses. Only three species of strict anaerobes able to grow on mucin were isolated from the enrichments of five different microbiota: Clostridium disporicum, Clostridium tertium, and Paraclostridium benzoelyticum. The limited number of species isolated confirms that in the gut the degradation of these glycoproteins results from cooperation and cross-feeding among several species exhibiting different metabolic capabilities.

Host-Microbiome Interactions Mediated by Phenolic Metabolites in Chronically Critically Ill Patients

The community structure and metabolic potential of gut microbiome is not well investigated, especially in chronically critically ill patients with prolonged dependence on support systems after severe brain disorders. Microbial phenolic metabolites can target the brain function by the direct and indirect modulation of inflammation. The aim of this study was to investigate the features of the gut microbiota and profile of certain metabolites in the progression and reversibility of neurological disorders in chronically critically ill patients. Fecal samples were collected in dynamics from such patients (n = 44) and analyzed using 16S rRNA sequencing. Serum microbial and mitochondrial metabolites were measured by GC-MS and compared with the biomarkers and clinical neurological scores. The identified associations between specific bacterial taxa in fecal samples, neurological status and serum levels of metabolites suggest that impacts on specific members of the gut microbiota and their metabolism might be a promising tool for regulating brain function in future.

Bacteremia Caused by the Eggerthella lenta in a Previously Healthy 30-Year-Old Man with Acute Suppurative Appendicitis: A Case Report from China

Eggerthella lenta is part of the normal bacterial flora of the intestinal tract, but may cause life-threatening infections. E. lenta has been isolated from blood, abscesses, wounds, skin ulcers, and intra-abdominal infections. However, due to historical difficulties with laboratory identification by conventional biochemical methods, some cases of E. lenta infection have previously gone undiagnosed, especially in China where E. lenta infections are very rare. Recently, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), a new type of technology, has made it possible to identify E. lenta. We report a case of postoperative infection caused by E. lenta which was treated successfully using meropenem.