-
PloS One 2021Enterococci have the dual characteristics of being opportunistic pathogens and promising probiotics. The isolation from patients of CDC PNS-E2, a newly described...
Enterococci have the dual characteristics of being opportunistic pathogens and promising probiotics. The isolation from patients of CDC PNS-E2, a newly described Enterococcus species Enterococcus sanguinicola, may pose potential hazards. Enterococcus thailandicus from fermented sausage is a senior subjective synonym of E. sanguinicola. In this study, Enterococcus thailandicus TC1 was first isolated in healthy pigs in Tongcheng, China and identified by phenotypic analysis and 16S rRNA-based techniques. To evaluate the strain safety, an approach including virulence factors, antibiotic resistance, and animal experiments was adopted. The results show that cylA, gelE, esp, agg, ace, efaAfm, efaAfs, ptsD genes were undetected, and that the strain was sensitive or poorly resistant to some clinically relevant antibiotics. However, the isolated strain demonstrated β-hemolytic activity in rabbit blood agar plates. Analysis of animal experiments revealed that the isolated strain had no adverse effect on translocation and the internal organ indices, though significant differences in histology (villi height, crypts height) of ileum were observed. The data acquired suggest that E. thailandicus TC1 may be associated with a potential health risk.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; China; Drug Resistance, Bacterial; Enterococcus; Humans; Meat Products; RNA, Ribosomal, 16S; Rabbits; Swine; Virulence Factors
PubMed: 34197541
DOI: 10.1371/journal.pone.0254081 -
Frontiers in Bioengineering and... 2020New anticancer agents are continually needed because cancerous cells continue to evolve resistance to the currently available chemotherapeutic agents. The aim of the...
New anticancer agents are continually needed because cancerous cells continue to evolve resistance to the currently available chemotherapeutic agents. The aim of the present study was to screen, purify and characterize a hepatotoxic bacteriocin from species. The production of bacteriocin from the isolates was achieved based on their antibacterial activity against indicator reference strains. isolates showed a broad spectrum of antibacterial activity by forming inhibition zones with diameters ranged between 12 and 29 mm. The most potent bacteriocin producing strain was molecularly identified as . The crude extracted bacteriocin was purified by cation exchange and size exclusion chromatography that resulted in 83 fractions. Among them, 18 factions were considered as bacteriocins based on their positive antibacterial effects. The anticancer effects of the purified bacteriocins were tested against HepG2 cell line. The most promising enterocin (LNS18) showed the highest anticancer effects against HepG2 cells (with 75.24% cellular inhibition percentages), with IC50 value 15.643 μM and without any significant cytotoxic effects on normal fibroblast cells (BJ ATCC® CRL-2522™). The mode of anticancer action of enterocin LNS18 against HepG2 cells could be explained by its efficacy to induce cellular ROS, decrease HepG2 CD markers and arrest cells in G0 phase. Amino acid sequence of enterocin LNS18 was determined and the deduced peptide of the structural gene showed 86 amino acids that shared 94.7% identity with enterocin NKR-5-3B from . Enterocin LNS18 consisted of 6 α-helices; 5 circular and one linear. Model-template alignment constructed between enterocin LNS18 and NKR-5-3B revealed 95.31% identity. The predicted 3D homology model of LNS18, after circularization and release of 22 amino acids, showed the formation of a bond between Leu23 and Trp86 amino acid residues at the site of circularization. Furthermore, areas of positive charges were due to the presence of 6 lysine residues resulting in a net positive charge of +4 on the bacteriocin surface. Based on the above mentioned results, our characterized bacteriocin is a promising agent to target liver cancer without any significant toxic effects on normal cell lines.
PubMed: 32656185
DOI: 10.3389/fbioe.2020.00450 -
Antibiotics (Basel, Switzerland) May 2023Antimicrobial resistance (AMR) is one of the biggest threats to public health. The food chain has been recognised as a vehicle for transmitting AMR bacteria. However,...
BACKGROUND
Antimicrobial resistance (AMR) is one of the biggest threats to public health. The food chain has been recognised as a vehicle for transmitting AMR bacteria. However, information about resistant strains isolated from African traditional fermented foods remains limited. is a traditional, naturally fermented milk product consumed by many pastoral communities across West Africa. The main aim of this study was to investigate and determine the AMR patterns of lactic acid bacteria (LAB) involved in the traditional fermentation of milk for production, and the presence of transferable AMR determinants.
METHODS
One hundred (100) LAB isolates from identified in a previous study as , , , , , and were investigated. The minimum inhibitory concentration (MIC) was determined for 18 antimicrobials using the micro-broth dilution method. In addition, LAB isolates were screened for 28 antimicrobial resistance genes using PCR. The ability of LAB isolates to transfer tetracycline and streptomycin resistance genes to was also investigated.
RESULTS
The experiments revealed variable antimicrobial susceptibility according to the LAB isolate and the antimicrobial tested. The tetracycline resistance genes (S) and (M) were detected in isolates 52 and 10. Additionally, (E) encoding resistance to streptomycin was detected in 52. The conjugation experiments suggested that the (S) and (E) genes were transferable in vitro from isolate 52 to JH2-2.
SIGNIFICANCE AND IMPACT
Traditional fermented foods play a significant role in the diet of millions of people in Africa, yet their contribution to the burden of AMR is largely unknown. This study highlights that LAB involved in traditionally fermented foods could be potential reservoirs of AMR. It also underscores the relevant safety issues of 52 and 10 for use as starter cultures as they carry transferable AMR genes. Starter cultures are an essential aspect of improving the safety and quality attributes of African fermented foods. However, AMR monitoring is an important safety aspect in the selection of starter cultures for improving traditional fermentation technologies.
PubMed: 37237746
DOI: 10.3390/antibiotics12050843 -
Journal of Food Protection Sep 2018The present study aimed at identifying and assessing antimicrobial resistance of Enterococcus spp. isolated from small and medium enterprise slaughterhouses in Kenya. In...
The present study aimed at identifying and assessing antimicrobial resistance of Enterococcus spp. isolated from small and medium enterprise slaughterhouses in Kenya. In total, 67 isolates were recovered from 48 of 195 samples examined from beef carcasses, personnel, and cutting equipment in five small and medium enterprise slaughterhouses. The isolates were identified by using matrix-assisted laser desorption-ionization time of flight mass spectrometry and screened thereafter for their resistance against 12 antibiotics by using a disk diffusion assay. The isolates ( n = 67) included Enterococcus faecalis (41.8%), Enterococcus mundtii (17.9%), Enterococcus thailandicus (13.4%), Enterococcus faecium (9.0%), Enterococcus hirae (7.5%), Enterococcus casseliflavus (6.0%), and Enterococcus devriesei (4.5%). None of the isolates were resistant to ciprofloxacin, penicillin, ampicillin, vancomycin, nitrofurantoin, teicoplanin, linezolid, and levofloxacin. Resistance to rifampin (46.3%), erythromycin (23.9%), tetracycline (20.9%), and chloramphenicol (7.5%) was distributed among six of the seven species. All E. thailandicus were resistant to rifampin, erythromycin, and tetracycline. E. faecalis was resistant to rifampin (60.7%), tetracycline (17.9%), erythromycin (14.3%), and chloramphenicol (10.7%). Resistance to two or three antibiotics was observed in 26.9% of the enterococci isolates. The isolation of enterococci that are resistant to clinically relevant antibiotics, such as erythromycin, is of a serious concern given the role enterococci play in the transfer of antibiotic resistance genes.
Topics: Abattoirs; Animals; Anti-Bacterial Agents; Cattle; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Enterococcus; Kenya; Microbial Sensitivity Tests; Phylogeny
PubMed: 30080119
DOI: 10.4315/0362-028X.JFP-18-130 -
Journal of Applied Microbiology Feb 2013To isolate and characterize bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria from the intestine of grey mullet.
Screening and characterization of LAB-produced bacteriocin-like substances from the intestine of grey mullet (Mugil cephalus L.) as potential biocontrol agents in aquaculture.
AIM
To isolate and characterize bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria from the intestine of grey mullet.
METHODS AND RESULTS
Inhibitory activity against at least one or more indicator strains was observed in one Enterococcus thailandicus, one Enterococcus faecium and two Lactococcus garvieae strains. Enterococcus faecium B3-8 and Ent. thailandicus B3-22 showed the greatest inhibitory activities against Listeria monocytogenes ATCC 19111 and were therefore further characterized. The results suggested that the inhibitory substances from the two strains showed similar characteristics with respect to sensitivity to heat and proteolytic enzymes. BLIS from Ent. thailandicus B3-22 was characterized by a broader inhibitory spectrum than that from Ent. faecium B3-8. SDS-PAGE revealed that the molecular size of partially purified BLISs from Ent. faecium B3-8 and Ent. thailandicus B3-22 was c. 5 and 3 kDa, respectively. The molecular mass of purified bacteriocin from Ent. thailandicus B3-22 was further determined to be 6319 Da by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The results indicated that BLIS from Ent. thailandicus B3-22 can effectively inhibit the growth of all tested L. garvieae strains.
CONCLUSIONS
The findings obtained in this study suggest the potential use of Ent. thailandicus B3-22 as a biocontrol agent against pathogenic L. garvieae in the aquaculture.
SIGNIFICANCE AND IMPACT OF THE STUDY
This is the first report describing the characteristics of BLIS from Ent. thailandicus that showed potential for use as a biocontrol agent in the aquaculture.
Topics: Animals; Anti-Bacterial Agents; Aquaculture; Bacteriocins; Biological Control Agents; Enterococcus; Enterococcus faecium; Hot Temperature; Intestines; Listeria monocytogenes; Molecular Weight; Smegmamorpha
PubMed: 23075097
DOI: 10.1111/jam.12041 -
BMC Microbiology Mar 2017Enterococcus is ubiquitous in nature and is a commensal of both the bovine and human gastrointestinal (GI) tract. It is also associated with clinical infections in...
BACKGROUND
Enterococcus is ubiquitous in nature and is a commensal of both the bovine and human gastrointestinal (GI) tract. It is also associated with clinical infections in humans. Subtherapeutic administration of antibiotics to cattle selects for antibiotic resistant enterococci in the bovine GI tract. Antibiotic resistance genes (ARGs) may be present in enterococci following antibiotic use in cattle. If located on mobile genetic elements (MGEs) their dissemination between Enterococcus species and to pathogenic bacteria may be promoted, reducing the efficacy of antibiotics.
RESULTS
We present a comparative genomic analysis of twenty-one Enterococcus spp. isolated from bovine feces including Enterococcus hirae (n = 10), Enterococcus faecium (n = 3), Enterococcus villorum (n = 2), Enterococcus casseliflavus (n = 2), Enterococcus faecalis (n = 1), Enterococcus durans (n = 1), Enterococcus gallinarum (n = 1) and Enterococcus thailandicus (n = 1). The analysis revealed E. faecium and E. faecalis from bovine feces share features with human clinical isolates, including virulence factors. The Tn917 transposon conferring macrolide-lincosamide-streptogramin B resistance was identified in both E. faecium and E. hirae, suggesting dissemination of ARGs on MGEs may occur in the bovine GI tract. An E. faecium isolate was also identified with two integrative conjugative elements (ICEs) belonging to the Tn916 family of ICE, Tn916 and Tn5801, both conferring tetracycline resistance.
CONCLUSIONS
This study confirms the presence of enterococci in the bovine GI tract possessing ARGs on MGEs, but the predominant species in cattle, E. hirae is not commonly associated with infections in humans. Analysis using additional complete genomes of E. faecium from the NCBI database demonstrated differential clustering of commensal and clinical isolates, suggesting that these strains may be specifically adapted to their respective environments.
Topics: Animals; Anti-Bacterial Agents; Bacteriophages; CRISPR-Cas Systems; Cattle; Cattle Diseases; Cluster Analysis; DNA Transposable Elements; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Enterococcus; Enterococcus faecalis; Enterococcus faecium; Enterococcus hirae; Feces; Gastrointestinal Microbiome; Genome, Bacterial; Genomics; Humans; Interspersed Repetitive Sequences; Lincosamides; Macrolides; Microbial Sensitivity Tests; Multilocus Sequence Typing; Phylogeny; Polymorphism, Single Nucleotide; Streptogramin B; Tetracycline Resistance; Virulence Factors
PubMed: 28270110
DOI: 10.1186/s12866-017-0962-1 -
Antimicrobial Agents and Chemotherapy Jan 2013Seventy-seven porcine Enterococcus isolates with florfenicol MICs of ≥16 μg of were/ml screened for the presence of the multiresistance gene cfr, its location on...
Seventy-seven porcine Enterococcus isolates with florfenicol MICs of ≥16 μg of were/ml screened for the presence of the multiresistance gene cfr, its location on plasmids, and its genetic environment. Three isolates-Enterococcus thailandicus 3-38 (from a porcine rectal swab collected at a pig farm), Enterococcus thailandicus W3, and Enterococcus faecalis W9-2 (the latter two from sewage at a different farm), carried the cfr gene. The SmaI pulsed-field gel electrophoresis patterns of the three isolates differed distinctly. In addition, E. faecalis W9-2 was assigned to a new multilocus sequence type ST469. Mating experiments and Southern blot analysis indicated that cfr is located on conjugative plasmids pW3 (∼75 kb) from E. thailandicus W3, p3-38 (∼72 kb) from E. thailandicus 3-38, and pW9-2 (∼55 kb) from E. faecalis W9-2; these plasmids differed in their sizes, additional resistance genes, and the analysis of the segments encompassing the cfr gene. Sequence analysis revealed that all plasmids harbored a 4,447-bp central region, in which cfr was bracketed by two copies of the novel insertion sequence ISEnfa4 located in the same orientation. The sequences flanking the central regions of these plasmids, including the partial tra gene regions and a ω-ε-ζ toxin-antitoxin module, exhibited >95% nucleotide sequence identity to the conjugative plasmid pAMβ1 from E. faecalis. Conjugative plasmids carrying cfr appear to play an important role in the dissemination and maintenance of the multiresistance gene cfr among enterococcal isolates and possibly other species of Gram-positive bacteria.
Topics: Animals; Animals, Domestic; Anti-Bacterial Agents; Bacterial Proteins; Conjugation, Genetic; DNA Transposable Elements; Drug Resistance, Multiple, Bacterial; Enterococcus; Gram-Positive Bacterial Infections; Methyltransferases; Microbial Sensitivity Tests; Multilocus Sequence Typing; Plasmids; Sequence Analysis, DNA; Swine; Swine Diseases
PubMed: 23070165
DOI: 10.1128/AAC.01605-12 -
Journal of Clinical Microbiology Jul 2011Several of the more recently proposed new species of Enterococcus are nearly identical based on 16S rRNA gene sequence analysis and phenotypic traits. In the present...
Reevaluation of the taxonomic status of recently described species of Enterococcus: evidence that E. thailandicus is a senior subjective synonym of "E. sanguinicola" and confirmation of E. caccae as a species distinct from E. silesiacus.
Several of the more recently proposed new species of Enterococcus are nearly identical based on 16S rRNA gene sequence analysis and phenotypic traits. In the present study, DNA-DNA reassociation experiments, in conjunction with sequencing of the 16S rRNA and rpoB genes, provided evidence that "Enterococcus sanguinicola" and Enterococcus thailandicus actually represent the same species. In contrast, Enterococcus caccae and Enterococcus silesiacus, two other species with nearly identical 16S rRNA gene sequences, were confirmed to be separate species.
Topics: Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; DNA-Directed RNA Polymerases; Enterococcus; Humans; Nucleic Acid Hybridization; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 21543565
DOI: 10.1128/JCM.00399-11 -
Genomics Jan 2021Colitis induced by C. difficile is one of the most common and costly healthcare-related infections for humans. Probiotics are one of the most promising approaches for...
Colitis induced by C. difficile is one of the most common and costly healthcare-related infections for humans. Probiotics are one of the most promising approaches for controlling CDI. Here, we presented the isolation, safety, and probiotic property evaluation of a novel E. thailandicus strain, d5B, with effective antimicrobial activity against C. difficile. Strain d5B showed strong bactericidal effects on at least 54C. difficile strains. Safety tests showed that strain d5B was sensitive to clinically important antibiotics, and had no haemolytic and cytotoxic activities. Whole genomic analysis showed strain d5B only contained one aminoglycoside resistance gene located in the chromosome. Moreover, d5B was devoid of functional virulence genes. Finally, strain d5B exhibited probiotic properties, such as tolerance to the gastrointestinal tract, and adhered well to HT-29 cells. In conclusion, the E. thailandicus strain d5B should be investigated further for useful properties as a novel candidate probiotic for controlling CDI.
Topics: Animals; Anti-Bacterial Agents; Cells, Cultured; Chlorocebus aethiops; Clostridioides difficile; Enterococcus; HT29 Cells; Humans; Vero Cells
PubMed: 32956846
DOI: 10.1016/j.ygeno.2020.09.032 -
New Microbes and New Infections Jun 2023
PubMed: 37179572
DOI: 10.1016/j.nmni.2023.101137