A potentially probiotic strain of Enterococcus faecalis from human milk that is avirulent, antibiotic sensitive, and nonbreaching of the gut barrier

The distribution and antibiotic-resistant characteristics and risk factors of pathogens associated with clinical biliary tract infection in humans

Introduction

Biliary Infection in patients is a common and important phenomenon resulting in severe complications and high morbidity, while the distributions and drug resistance profiles of biliary bacteria and related risk factors are dynamic. This study explored the characteristics of and risk factors for biliary infection to promote the rational use of antibiotics in clinically.

Methods

Bacterial identification and drug susceptibility testing were completed using the Vitek 2 Compact analysis system. The distribution and antibiotic-resistant characteristics of 3,490 strains of biliary bacteria in patients at Nankai Hospital from 2019 to 2021 were analyzed using Whonet 5.6 and SPSS 26.0 software. We then retrospectively analyzed the clinical data and risk factors associated with 2,340 strains of Gram-negative bacilli, which were divided into multidrug-resistant bacteria (1,508 cases) and non-multidrug-resistant bacteria (832 cases) by a multivariate Cox regression model.

Results and discussion

A total of 3,490 pathogenic bacterial strains were isolated from bile samples, including 2,340 (67.05%) Gram-negative strains, 1,029 (29.48%) Gram-positive strains, and 109 (4.56%) fungal strains. The top five pathogenic bacteria were Escherichia coli, Klebsiella pneumoniae, Enterococcus faecium, Enterococcus faecalis, and Pseudomonas aeruginosa. The rate of Escherichia coli resistance to ciprofloxacin increased (p < 0.05), while the resistance to amikacin decreased (p < 0.05). The resistance of Klebsiella pneumoniae to cephalosporins, carbapenems, β-lactamase inhibitors, cephalases, aminoglycosides, and quinolones increased (p < 0.05), and the resistance of Pseudomonas aeruginosa to piperacillin, piperacillin/tazobactam, ticacillin/clavulanic acid, and amicacin declined significantly (p < 0.05). The resistance of Enterococcus faecium to tetracycline increased by year (p < 0.05), and the resistance of Enterococcus faecalis to erythromycin and high-concentration gentamicin declined (p < 0.05). Multivariate logistic regression analysis suggested that the administration of third- or fourth-generation cephalosporins was an independent risk factor for biliary infection. In summary, Gram-negative bacilli were the most common pathogenic bacteria isolated from biliary infection patients, especially Escherichia coli, and the rates and patterns of drug resistance were high and in constant flux; therefore, rational antimicrobial drug use should be carried out considering risk factors.

Probiotic Enterococcus faecalis surface-delivering key domain of EtMIC3 proteins: immunoprotective efficacies against Eimeria tenella infection in chickens

IMPORTANCE

Avian coccidiosis caused by Eimeria brings huge economic losses to the poultry industry. Although live vaccines and anti-coccidial drugs were used for a long time, Eimeria infection in chicken farms all over the world commonly occurred. The exploration of novel, effective vaccines has become a research hotspot. Eimeria parasites have complex life cycles, and effective antigens are particularly critical to developing anti-coccidial vaccines. Microneme proteins (MICs), secreted from microneme organelles located at the parasite apex, are considered immunodominant antigens. Eimeria tenella microneme 3 (EtMIC3) contains four conserved repeats (MARc1, MARc2, MARc3, and MARc4) and three divergent repeats (MARa, MARb, and MARd), which play a vital role during the Eimeria invasion. Enterococcus faecalis is a native probiotic in animal intestines and can regulate intestinal flora. In this study, BC1 and C4D domains of EtMIC3, BC1 or C4D fusing to dendritic cells targeting peptides, were surface-displyed by E. faecalis, respectively. Oral immunizations were performed to investigate immune protective effects against Eimeria infection.

Genome sequencing of Enterococcus faecium NT04, an oral microbiota revealed the production of enterocin A/B active against oral pathogens

Objective

This study aimed to isolate and investigate a bacterium from an Egyptian adult's healthy oral cavity, focusing on its probiotic properties, especially its antagonistic activity against oral pathogens.

Methods

The isolated bacterium NT04 using 16S rRNA gene sequencing, was identified as Enterococcus faecium. In this study, the whole genome of Enterococcus faecium NT04 was sequenced and annotated by bioinformatics analysis tools.

Results

Numerous genes encoding the production of diverse metabolic and probiotic properties, such as bacteriocin-like inhibitory substances (Enterocin A and B), cofactors, antioxidants, and vitamins, were confirmed by genomic analysis. There were no pathogenicity islands or plasmid insertions found. This strain is virulent for host colonization rather than invasion.

Conclusion

Genomic characteristics of strain NT04 support its potentiality as an anti-oral pathogen probiotic candidate.

Untargeted metabolite profiling of Enterococcus villorum SB2, isolated from the vagina of pregnant women, by HR-LCMS

Enterococcus bacteria are studied in various sectors including fermentation, food and dairy industries,as well as studied for their probiotic properties but have limited use due to their possible pathogenic behavior. The present report talks about the metabolites produced, by the previously isolated Enterococcus strain, E.villorum SB2 (accession number KX830968), from the vaginal source. The growth of the bacteria in three types of media (M17, MRS and LAPTg) was compared, where the M17 media gave better bacterial colonies, also maximum growth rate was observed in M17 media (T_d = 1.6 h & k = 0.4 h^-1), and thus was selected as the metabolite production media. Further, the studied bacteria did not show any hemolytic activity, making it safe for industrial applications. The HR-LCMS results showed the production of various amino acids, organic acids, peptides, and other metabolites like flavonoids (Quercetin 3-O-Manoglucoside), terpenoids (7',8',Dihydro-8'-hydroxycitraniaxanthin, O-Methylganoderic acid O, Thalicsessine, Austinol, Valdiate), indole derivatives produced by tryptophan metabolism (5-hydroxykynurenamine, 2S,4R)-4-(9H-Pyrido[3,4-b]indol-1-yl)-1,2,4-butanetriol, Indoleacrylic acid), antimicrobial compounds (Fortimicin A) and fatty acids (Stearic acid, Myristic acid), which were earlier unreported form Enterococcus species opening new scope for discovering new industrial applications of the strain. As the studied bacteria has been reported to be a potential probiotic, the detection of these industrially important metabolites can be studied further in future studies to reveal the potential industrial applications of the strain.