Altered Profiles of Gut Microbiota in Klebsiella pneumoniae-Induced Pyogenic Liver Abscess

Alterations of Gut Microbiota in Pyogenic Liver Abscess Patients with and without Type 2 Diabetes Mellitus

Purpose

The clinical manifestations of pyogenic liver abscess (PLA) vary between patients with and without diabetes mellitus (DM). However, the relationship between PLA and the gut microbiome remains unknown. This study analyzed the composition of gut microbiota in PLA patients with and without DM and healthy controls (HCs) with the goal of identifying potential reasons for the observed variations in clinical manifestations.

Patients and Methods

Using 16S ribosomal RNA(16S rRNA) gene sequencing, we analyzed the compositions of gut microbiota in 32 PLA patients with DM, 32 PLA patients without DM, and 29 matched HCs.

Results

In PLA patients with DM, the D-dimer level, fibrinogen degradation products, and thrombin time were significantly higher compared to the PLA patients without DM (P < 0.05). The abundance and diversity of intestinal flora were reduced in both groups of PLA patients compared with the HCs (P < 0.05). Specifically, the PLA patients with DM showed significant decreases in the relative abundances of Bacteroides, Blautia, Prevotella9, and Faecalibacterium, whereas Enterococcus and Escherichia-Shigella were relatively more abundant (P < 0.05). Compared to PLA patients without DM, those with DM had lower relative abundances of Lactobacillus and Klebsiella (P < 0.05) and showed different bacterial flora, including Anaerosporobacter and Megamonas.

Conclusion

PLA patients with DM exhibited more severe clinical manifestations of PLA compared to patients without DM. It is important to monitor blood coagulation in PLA patients with DM to prevent the development of thrombotic diseases. Additionally, PLA patients with DM exhibit distinct differences in the composition and diversity of their intestinal flora compared to both PLA patients without DM and HCs.

Elucidating the causal association between gut microbiota and intrahepatic cholangiocarcinoma through Mendelian randomization analysis

Background

Intrahepatic cholangiocarcinoma (ICC) is an aggressive liver cancer with poor prognosis. The gut microbiota has been linked to ICC, but evidence for causality is lacking. Elucidating causal gut microbiota-ICC links could inform prevention and treatment strategies.

Materials and methods

We performed a bidirectional two-sample Mendelian randomization (MR) study to investigate causal associations between gut microbiota and ICC risk. Genome-wide significant single nucleotide polymorphisms (SNPs) associated with gut microbiota abundances were utilized as instrumental variables (IVs). Multiple methods assessed causality and sensitivity analyses evaluated result robustness. Bioinformatics analysis of genetic loci linked to gut microbiota and ICC examined potential mechanisms.

Results

Genetically predicted increases in Veillonellaceae, Alistipes, Enterobacteriales, and Firmicutes were suggestively associated with higher ICC risk, while increases in Anaerostipes, Paraprevotella, Parasutterella, and Verrucomicrobia appeared protective. Bioinformatics analysis revealed differentially expressed genes near gut microbiota-associated loci may influence ICC through regulating pathways and tumor immune microenvironment.

Conclusion

Our findings provide suggestive evidence for causal links between specific gut microbiota and ICC risk.

Fusion data from FT-IR and MALDI-TOF MS result in more accurate classification of specific microbiota

Microbes are usually present as a specific microbiota, and their classification remains a challenge. MALDI-TOF MS is particularly successful in library-based microbial identification at the species level as it analyzes the molecular weight of peptides and ribosomal proteins. FT-IR allows more accurate classification of bacteria at the subspecies level due to the high sensitivity, specificity and repeatability of FT-IR signals from bacteria, which is not achievable with MALDI-TOF MS. Previous studies have shown that more accurate identification results can be obtained by the fusion of FT-IR and MALDI-TOF MS spectral data. Here, we constructed 20 groups of model microbiota samples and used FT-IR, MALDI-TOF MS, and their fusion data to classify them. Hierarchical clustering analysis (HCA) showed that the classification accuracy of FT-IR, MALDI-TOF MS, and the fusion data was 85%, 90%, and 100%, respectively. These results indicate that both FT-IR and MALDI-TOF MS can effectively classify specific microbiota, and the fusion of their spectral data could improve the classification accuracy. The FT-IR and MALDI-TOF MS data fusion strategy may be a promising technology for specific microbiota classification.

Clinical characteristics and management of 106 patients with pyogenic liver abscess in a traditional Chinese hospital

This is a retrospective study of clinical data from 106 patients with pyogenic liver abscess (PLA) treated in a traditional Chinese hospital during the eight years preceding this publication. We aimed to provide evidence to improve the diagnosis accuracy and the treatment strategies for PLAs. We collected records of patients treated at the Guangxing Hospital, which is affiliated to the Zhejiang Traditional Chinese University in Hangzhou, and we collected their general background information, laboratory and imaging features, and clinical manifestations and outcomes to perform a retrospective analysis. Diabetes mellitus (45.3%, 48/106), biliary calculi (36.8%, 39/106), and history of abdominal surgery (15.1%, 16/106) were the three most common PLA risk factors present in our cohort. Fever and chills (95.3%, 101/106), right upper quadrant pain/epigastric discomfort (68.9%, 73/106), nausea and vomiting (38.8%, 41/106), and cough and sputum (14.2%, 15/106) were the most common clinical manifestations of PLA. Most patients had the abscesses in the right liver lobe, and the most commonly found bacteria were Klebsiella pneumoniae (54.8%, 42/76), Escherichia coli (35.1%, 27/76), and Streptococcus pneumoniae (3.9%, 3/76). Liver Doppler ultrasound is a conventional and effective method to identify liver abscesses. Most patients were treated using a percutaneous puncture under B-ultrasound guidance. Most patients (n = 104 or 98.1%) were cured, one patient (0.9%) died, and one was discharged with multiple abscesses post treatment.

Klebsiella pneumoniae infection is associated with alterations in the gut microbiome and lung metabolome

Gut microbiota is involved in maintaining homeostasis, and intestinal dysbiosis may lead to opportunistic infections and diseases. Pathogens can disrupt the gut homeostasis and establish colonization, but how they modulate the microbiome and metabolome along the gut-lung axis warrants further investigation. In the present study, we used a classical low virulence Klebsiella pneumoniae (cKp) strain to address this question. We assessed the gut microbiome and lung metabolome in cKp-infected mice by 16S rRNA sequencing and untargeted liquid chromatography-mass spectrometry, respectively. Our data revealed that cKp infection reduced gut microbiota diversity and altered microbiome composition. Specifically, cKp infection increased the abundance of MWH-CFBk5 and Actinomadura and reduced the abundance of Lachnospiraceae_NK4A136_group, Clostridium sensu_stricto 1, Bifidobacterium, and Intestinimonas at the genus level. Notably, caffeine and caffeine metabolism were significantly affected in the lung by cKp infection. Moreover, Spearman correlation analysis revealed remarkable correlations of specific lung metabolites and bacteria species at the genus level. These findings suggest that cKp infection is linked to gut dysbiosis and alterations in the lung metabolome. This study is of significance for developing innovative gut microbiota-directed therapy for respiratory diseases.

Metagenome Analysis of the Bacterial Characteristics in Invasive Klebsiella Pneumoniae Liver Abscesses

Background

Klebsiella pneumoniae liver abscess (KPLA) combined with extrahepatic migratory infection (EMI) is defined as invasive KPLA (IKPLA) and is associated with a poor prognosis. The mechanism of IKPLA formation is yet to be elucidated. In this study, metagenomic sequencing was used to compare the bacterial characteristics between IKPLA and KPLA to explore the underlying mechanism of invasiveness.

Methods

Clinical details, imaging, and microbial features were retrospectively evaluated by medical record review. Metagenomic sequencing was performed on the pus samples of liver abscesses whose culture results were indicative of monomicrobial Klebsiella pneumoniae (K. pneumoniae). Bacterial diversity and composition in IKPLA and KPLA were comparatively analyzed, and the key pathways and genes that may affect invasiveness were further explored.

Results

Sixteen patients were included in this study. Five patients with EMI were included in the IKPLA group, and the other eleven patients without EMI were assigned to the KPLA group. There was no statistical difference in the hypermucoviscous phenotype and serotype of K. pneumoniae between the two groups. The bacterial diversity of IKPLA was lower than that of KPLA. The abundant taxa in the IKPLA group were primarily species of unclassified Enterobacteriaceae and K. pneumoniae. The KPLA group had a high abundance of the genera Tetrasphaera and Leuconostoc. Metabolic pathway genes represented most of the enriched genes in IKPLA. Fourteen pathogenic genes with significant differences in abundance were identified between the two groups, including ybtS, fepC, phoQ, acrB, fimK, magA, entC, arnT, iucA, fepG, oqxB, entA, tonB, and entF (p < 0.001).

Conclusion

The diversity and bacterial composition of IKPLA were significantly different from those of KPLA. Microbiological changes in the abscess, activation of the related metabolic pathways, and the pathogenic gene expression may constitute a novel mechanism that regulates the invasiveness of KPLA.

Improved functionality of Ligilactobacillus salivarius Li01 in alleviating colonic inflammation by layer-by-layer microencapsulation

The low viability during gastrointestinal transit and poor mucoadhesion considerably limits the effectiveness of Ligilactobacillus salivarius Li01 (Li01) in regulating gut microbiota and alleviating inflammatory bowel disease (IBD). In this study, a delivery system was designed through layer-by-layer (LbL) encapsulating a single Li01cell with chitosan and alginate. The layers were strengthened by cross-linking to form a firm and mucoadhesive shell (~10 nm thickness) covering the bacterial cell. The LbL Li01 displayed improved viability under simulated gastrointestinal conditions and mucoadhesive function. Almost no cells could be detected among the free Li01 after 2 h incubation in digestive fluids, while for LbL Li01, the total reduction was around 3 log CFU/mL and the viable number of cells remained above 6 log CFU/mL. Besides, a 5-fold increase in the value of rupture length and a two-fold increase in the number of peaks were found in the (bacteria-mucin) adhesion curves of LbL Li01, compared to those of free Li01. Oral administration with LbL Li01 on colitis mice facilitated intestinal barrier recovery and restoration of the gut microbiota. The improved functionality of Li01 by LbL encapsulation could increase the potential for the probiotic to be used in clinical applications to treat IBD; this should be explored in future studies.

Decreased Ecological Resistance of the Gut Microbiota in Response to Clindamycin Challenge in Mice Colonized with the Fungus Candida albicans

The mammalian gut microbiota is a complex community of microorganisms which typically exhibits remarkable stability. As the gut microbiota has been shown to affect many aspects of host health, the molecular keys to developing and maintaining a "healthy" gut microbiota are highly sought after. Yet, the qualities that define a microbiota as healthy remain elusive. We used the ability to resist change in response to antibiotic disruption, a quality we refer to as ecological resistance, as a metric for the health of the bacterial microbiota. Using a mouse model, we found that colonization with the commensal fungus Candida albicans decreased the ecological resistance of the bacterial microbiota in response to the antibiotic clindamycin such that increased microbiota disruption was observed in C. albicans-colonized mice compared to that in uncolonized mice. C. albicans colonization resulted in decreased alpha diversity and small changes in abundance of bacterial genera prior to clindamycin challenge. Strikingly, co-occurrence network analysis demonstrated that C. albicans colonization resulted in sweeping changes to the co-occurrence network structure, including decreased modularity and centrality and increased density. Thus, C. albicans colonization resulted in changes to the bacterial microbiota community and reduced its ecological resistance.IMPORTANCECandida albicans is the most common fungal member of the human gut microbiota, yet its ability to interact with and affect the bacterial gut microbiota is largely uncharacterized. Previous reports showed limited changes in microbiota composition as defined by bacterial species abundance as a consequence of C. albicans colonization. We also observed only a few bacterial genera that were significantly altered in abundance in C. albicans-colonized mice; however, C. albicans colonization significantly changed the structure of the bacterial microbiota co-occurrence network. Additionally, C. albicans colonization changed the response of the bacterial microbiota ecosystem to a clinically relevant perturbation, challenge with the antibiotic clindamycin.

The impact of aspirin on Klebsiella pneumoniae liver abscess in diabetic patients

In this study, we aimed to investigate the impact of aspirin on the risk of pyogenic liver abscess caused by Klebsiella pneumoniae (KP-PLA) and invasive KP-PLA syndrome (IKPS) in diabetic patients. Diabetic patients who were propensity-score matched were retrospectively included from hospital-based database. Kaplan-Meier approach with a log-rank test was used to compare the cumulative incidences of KP-PLA including IKPS between aspirin users and non-users. Totally, 63,500 patients were analyzed after propensity-score matching (1:1). Compared with that of non-users, the incidence of KP-PLA was significantly reduced in aspirin users (0.31% vs. 0.50%, p < 0.01), but not for that of IKPS (0.02% vs. 0.03%, p = 0.29). Patients taking aspirin for ≥ 90 days had a significantly lower risk for KP-PLA (hazard ratio, 0.67; 95%CI, 0.50-0.90). Females, taking clopidogrel or metformin for ≥ 90 days, and taking H2-blockers or proton pump inhibitors (PPIs) for ≥ 5 days were also associated with a lower risk of KP-PLA. However, cholangitis and a glycated hemoglobin ≥ 8.5% were associated with an increased risk of KP-PLA.

Gastric Microbiota Alteration in Klebsiella pneumoniae-Caused Liver Abscesses Mice

Gastric microbiota provides a biological barrier against the invasion of foreign pathogens from the oral cavity, playing a vital role in maintaining gastrointestinal health. Klebsiella spp. of oral origin causes various infections not only in gastrointestinal tract but also in other organs, with Klebsiella pneumoniae serotype K1 resulting in a liver abscess (KLA) through oral inoculation in mice. However, the relationship between gastric microbiota and the extra-gastrointestinal KLA infection is not clear. In our study, a 454 pyrosequencing analysis of the bacterial 16S rRNA gene shows that the composition of gastric mucosal microbiota in mice with or without KLA infection varies greatly after oral inoculation with K. pneumoniae serotype K1 isolate. Interestingly, only several bacteria taxa show a significant change in gastric mucosal microbiota of KLA mice, including the decreased abundance of Bacteroides, Alisptipes and increased abundance of Streptococcus. It is worth noting that the abundance of Klebsiella exhibits an obvious increase in KLA mice, which might be closely related to KLA infection. At the same time, the endogenous antibiotics, defensins, involved in the regulation of the bacterial microbiota also show an increase in stomach and intestine. All these findings indicate that liver abscess caused by K. pneumoniae oral inoculation has a close relationship with gastric microbiota, which might provide important information for future clinical treatment.