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Journal of Dairy Science Aug 2020The objective of this study was to evaluate the antibacterial activities of extract derived from moringa leaves. In particular, the effect of moringa extract (Mor) on...
The objective of this study was to evaluate the antibacterial activities of extract derived from moringa leaves. In particular, the effect of moringa extract (Mor) on adhesion and invasion of Escherichia coli O55, Enterococcus faecalis, Staphylococcus simulans, and Serratia liquefaciens was evaluated in bovine mammary epithelial cells (MAC-T). Broth microdilution method, minimum inhibitory concentration and minimum bactericidal concentration assays, adhesion and invasion assays, and real-time PCR were performed. The minimum inhibitory concentration and minimum bactericidal concentration of Mor ranged from 12.5 to 50 mg/mL on 18 out of 27 tested isolates. Treatment of E. coli O55 with Mor (100 and 200 μg/mL) inhibited the adhesion and invasion on MAC-T cells via downregulation of adhesion factors (i.e., papC, f17c-A, and eaeA). Also, when MAC-T cells were pretreated with Mor (200 μg/mL, 12 h) and incubated with E. coli O55, Enterococcus faecalis, Staphylococcus simulans, or Serratia liquefaciens, both E. coli O55 and Enterococcus faecalis showed a significant decrease in adhesion and invasion. Staphylococcus simulans exhibited decreased adhesion and increased invasion. Serratia liquefaciens showed increased adhesion and decreased invasion. In addition, Mor increased mRNA expression of antioxidant enzymes (e.g., heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1, and thioredoxin reductase 1) in MAC-T cells. In conclusion, 12.5 to 50 mg/mL of Mor exhibited antibacterial activity against 18 out of 27 tested isolates. Also, pretreatment of 200 μg/mL of Mor to MAC-T cells modulated adhesion and invasion of E. coli O55 and other mastitis-associated pathogens. Furthermore, Mor increased antioxidant capacities in MAC-T cells, but further in vivo studies are needed.
Topics: Animals; Anti-Bacterial Agents; Bacterial Adhesion; Cattle; Enterococcus faecalis; Epithelial Cells; Escherichia coli; Escherichia coli Infections; Female; Mammary Glands, Animal; Mastitis, Bovine; Moringa; Plant Extracts
PubMed: 32475678
DOI: 10.3168/jds.2019-17774 -
Antimicrobial Agents and Chemotherapy May 2020Recent studies highlight the abundance of commensal agulase-egative taphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin...
Recent studies highlight the abundance of commensal agulase-egative taphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin immunological and microbial milieu to resist colonization or infection by opportunistic pathogens, including methicillin-resistant (MRSA), in a variety of mechanisms collectively termed colonization resistance. One potential colonization resistance mechanism is the application of quorum sensing, also called the ccessory ene egulator () system, which is ubiquitous among staphylococci. Common and rare CoNS make autoinducing peptides (AIPs) that function as MRSA inhibitors, protecting the host from invasive infection. In a screen of CoNS spent media, we found that , a rare human skin colonizer and frequent livestock colonizer, released potent inhibitors of all classes of MRSA signaling. We identified three classes and have shown intraspecies cross talk between noncognate types for the first time. The AIP-I structure was confirmed, and the novel AIP-II and AIP-III structures were solved via mass spectrometry. Synthetic AIPs inhibited MRSA signaling with nanomolar potency. in competition with MRSA reduced dermonecrotic and epicutaneous skin injury in murine models. The addition of synthetic AIP-I also effectively reduced MRSA dermonecrosis and epicutaneous skin injury in murine models. These results demonstrate potent anti-MRSA quorum sensing inhibition by a rare human skin commensal and suggest that cross talk between CoNS and MRSA may be important in maintaining healthy skin homeostasis and preventing MRSA skin damage during colonization or acute infection.
Topics: Animals; Bacterial Proteins; Humans; Methicillin-Resistant Staphylococcus aureus; Mice; Peptides; Quorum Sensing; Staphylococcal Infections; Staphylococcus
PubMed: 32253213
DOI: 10.1128/AAC.00172-20 -
Frontiers in Microbiology 2019is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs...
is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs by methicillin resistant has become a problem with increasing numbers of humans being infected by livestock strains. In colonization and virulence factor expression is controlled by the quorum sensing system, which responds to and is activated by self-generated, autoinducing peptides (AIPs). AIPs are also produced by coagulase negative staphylococci (CoNS) commonly found as commensals in both humans and animals, and interestingly, some of these inhibit activity. Here, we have addressed if cross-communication occurs between and CoNS strains isolated from pig nares, and if so, how properties such as host factor binding and biofilm formation are affected. From 25 pig nasal swabs we obtained 54 staphylococcal CoNS isolates belonging to 8 different species. Of these, none were able to induce as monitored by reporter gene fusions to regulated genes but a number of -inhibiting species were identified including , , , , and . After establishing that the inhibitory activity was mediated via AgrC, the receptor of AIPs, we synthesized selective AIPs to explore their effect on adhesion of to fibronectin, a host factor involved in colonization. Here, we found that the CoNS AIPs did not affect adhesion of except for strain 8325-4. When individual CoNS strains were co-cultured together with we observed variable degrees of biofilm formation which did not correlate with interactions. Our results show that multiple CoNS species can be isolated from pig nares and that the majority of these produce AIPs that inhibit . Further they show that the consequences of the interactions between CoNS and are complex and highly strain dependent.
PubMed: 31611856
DOI: 10.3389/fmicb.2019.02212 -
Journal of Dairy Science Dec 2019Coagulase-negative staphylococci (CNS) are one of the most common bovine mastitis pathogens found worldwide. In this study, we investigated the prevalence and...
Coagulase-negative staphylococci (CNS) are one of the most common bovine mastitis pathogens found worldwide. In this study, we investigated the prevalence and distribution of CNS species in mastitis milk samples and further characterized the methicillin-resistant (MR) CNS. A total of 311 CNS were isolated from 3,692 quarter milk samples from 1,373 dairy cattle at 81 farms between 2013 and 2017. Further evaluation of the CNS isolates revealed 14 CNS species among the samples and 3 predominant species-namely, Staphylococcus chromogenes, Staphylococcus simulans, and Staphylococcus epidermidis. Resistance was higher in S. epidermidis than in other CNS species except for resistance against oxacillin in Staphylococcus sciuri. Resistance to β-lactams was the most common in all CNS species (8.4% in ampicillin, 21.2% in oxacillin, and 13.5% in penicillin). Conversely, only minimal resistance to cephalothin, ceftiofur, and pirlimycin/novobiocin was found. Twenty-one isolates from 4 species were mecA-carrying MRCNS strains, including 18 S. epidermidis and 1 each of S. sciuri, Staphylococcus equorum, and Staphylococcus hominis. The majority of the mecA-carrying MRCNS isolates were produced in the biofilm. Furthermore, multidrug-resistant sequence type 179 isolate produced the strongest biofilm. Seven genotypes were detected in the 18 MR S. epidermidis strains, the most predominant of which persisted on a farm for 2 yr. Our findings for the antimicrobial susceptibility profiles and genotypic characterization of the MRCNS isolates could provide valuable information for controlling the spread of resistance and the selection of appropriate antimicrobial therapies for mastitis in the future. Further, strategic antibiotic use for mastitis treatment and hygienic management practices aimed at the prevention of the growth of resistant bacteria are urgently needed on dairy farms.
Topics: Animals; Anti-Bacterial Agents; Cattle; Coagulase; Drug Resistance, Bacterial; Farms; Female; Genotype; Mastitis, Bovine; Milk; Oxacillin; Prevalence; Republic of Korea; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis
PubMed: 31548061
DOI: 10.3168/jds.2019-17028 -
AIMS Microbiology 2019The increasing spread of antibiotic-resistant microorganisms has led to the necessity of developing alternative antimicrobial treatments. The use of peptidoglycan...
The increasing spread of antibiotic-resistant microorganisms has led to the necessity of developing alternative antimicrobial treatments. The use of peptidoglycan hydrolases is a promising approach to combat bacterial infections. In our study, we constructed a 2 kb-triple-acting fusion gene () encoding the N-terminal amidase-5 domain of streptococcal LambdaSA2 prophage endolysin (D-glutamine-L-lysin endopeptidase), a mid-protein amidase-2 domain derived from the staphylococcal phage 2638A endolysin (N-acetylmuramoyl-L-alanine amidase) and the mature version (246 residues) of the Lysostaphin bacteriocin (glycyl-glycine endopeptidase) at the C-terminus. The gene was expressed in plants using the non-replicating (CPMV)-based vector pEAQ-HT and the replicating AltMV)-based pGD5TGB123-MCS-CP3 vector, and in using pET expression vectors pET26b+ and pET28a+. The resulting poor expression of this fusion protein in plants prompted the construction of a gene codon-optimized for expression in tobacco plants, resulting in an improved codon adaptation index (CAI) from 0.79 ( gene) to 0.93 ( gene). Incorporation of the nt gene into the pEAQ-HT vector, followed by transient expression in , led to accumulation of TFnt to an approximate level of 0.12 mg/g of fresh leaf weight. Antimicrobial activity of purified plant- and bacterial-produced TFnt proteins was assessed against two strains of Gram-positive 305 and Newman. The results showed that plant-produced TFnt protein was preferentially active against 305, showing 14% of growth inhibition, while the bacterial-produced TFnt revealed significant antimicrobial activity against both strains, showing 68 (IC 25 µg/ml) and 60% (IC 71 µg/ml) growth inhibition against 305 and Newman, respectively. Although the combination of codon optimization and transient expression using the non-replicating pEAQ-HT expression vector facilitated production of the TFnt protein in plants, the most functionally active antimicrobial protein was obtained using the prokaryotic expression system.
PubMed: 31384710
DOI: 10.3934/microbiol.2019.2.158 -
Frontiers in Microbiology 2019Biogenic amines (BAs) in sausages represent a health risk for consumers, and thus investigating the BAs accumulation mechanism is important to control the BAs. In this...
Biogenic amines (BAs) in sausages represent a health risk for consumers, and thus investigating the BAs accumulation mechanism is important to control the BAs. In this study, the BAs profiles of 16 typical Chinese sausage samples were evaluated, and 8 kinds of common BAs were detected from different samples. As a whole, the BAs contents of the majority of Chinese sausage samples were within the safe dosage range, except that the total BAs and histamine concentrations of sample HBBD were above the toxic dosage levels. Furthermore, the bacterial and fungal communities of the Chinese sausage samples were investigated by high-throughput sequencing analysis, and , , , , , and were identified as the predominant genera. Accordingly, 13 representative strains were selected from the dominant genera, and their BAs formation and degradation properties were evaluated. Finally, the results of fermented meats model experiment indicated that the isolates including Sp, Se, Sc1, Sc2, and Ss could significantly reduce BAs, possessing the potential as the starter cultures to control the BAs in fermented meat products. The present study not only helped to explain the BAs accumulation mechanism in Chinese sausage, but also developed the candidates for potential BAs control in fermented meat products.
PubMed: 31130922
DOI: 10.3389/fmicb.2019.00872 -
Scientific Reports Apr 2019Staphylococcus simulans lysostaphin cleaves pentaglycine cross-bridges between stem peptides in the peptidoglycan of susceptible staphylococci, including S. aureus. This...
Staphylococcus simulans lysostaphin cleaves pentaglycine cross-bridges between stem peptides in the peptidoglycan of susceptible staphylococci, including S. aureus. This enzyme consists of an N-terminal catalytic domain and a cell wall binding domain (SH3b), which anchors the protein to peptidoglycan. Although structures of SH3bs from lysostaphin are available, the binding modes of peptidoglycan to these domains are still unclear. We have solved the crystal structure of the lysostaphin SH3b domain in complex with a pentaglycine peptide representing the peptidoglycan cross-bridge. The structure identifies a groove between β1 and β2 strands as the pentaglycine binding site. The structure suggests that pentaglycine specificity of the SH3b arises partially directly by steric exclusion of Cβ atoms in the ligand and partially indirectly due to the selection of main chain conformations that are easily accessible for glycine, but not other amino acid residues. We have revealed further interactions of SH3b with the stem peptides with the support of bioinformatics tools. Based on the structural data we have attempted engineering of the domain specificity and have investigated the relevance of the introduced substitutions on the domain binding and specificity, also in the contexts of the mature lysostaphin and of its bacteriolytic activity.
Topics: Amino Acid Sequence; Computational Biology; Computer Simulation; Escherichia coli; Lysostaphin; Models, Molecular; Peptidoglycan; Protein Binding; Protein Conformation; Protein Domains; Protein Engineering; Staphylococcus
PubMed: 30979923
DOI: 10.1038/s41598-019-42435-z -
Environmental Research Apr 2019The airborne fungal and bacterial species present in pig farm dust have not been well characterised even though these bioaerosols are known to cause inflammation and...
The airborne fungal and bacterial species present in pig farm dust have not been well characterised even though these bioaerosols are known to cause inflammation and other airway maladies. In this study, the microbial species and composition in airborne dust within and between pig farms were investigated. Passively sedimenting dust from six pig farms were collected using electrostatic dust collectors. The bacterial and fungal species were identified using matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and next generation sequencing (NGS). Dust samples taken within the same stable section revealed high resemblance and stability. Constrained statistical analysis of the microbial community compositions indicated that the types of stable did not appear to have a great effect on the bacterial and fungal β-diversity. In contrast to this, the farm from which samples were taken appeared to have the greatest effect on the bacterial β-diversity, but this trend was not observed for the fungal β-diversity. The most common bacteria and fungi according to NGS data were anaerobes typically associated with the pig intestinal tract and yeasts respectively. Bacterial sedimentation varied at a rate between 10 and 10 CFU/m/day, with the most common species after aerobic incubation being Aerococcus viridans and Staphylococcus equorum, while Clostridium perfringens and Staphylococcus simulans were the most common species after anaerobic incubation. A total of 28 different species of bacteria and fungi were classifiable as pathogens. In conclusion, the biodiversity in pig farm dust shows a high diversity of bacterial species. However, samples from the same stable section resembled each other, but also different sections within the same farm also resembled each other, thus indicating a high degree of community stability in the dust source. In regards to fungal identification, the biodiversity was observed to be similar between samples from different stable sections and farms, indicating a higher degree of similarities in the mycobiomes found across pig farms studied.
Topics: Air Microbiology; Animals; Bacteria; Biodiversity; Dust; Environmental Monitoring; Farms; Fungi; Swine
PubMed: 30771719
DOI: 10.1016/j.envres.2019.01.008 -
Case Reports in Infectious Diseases 2018is a coagulase-negative organism, mainly an animal pathogen. Reports of human infection have been infrequent, mainly in patients with repeated animal contact. We report...
is a coagulase-negative organism, mainly an animal pathogen. Reports of human infection have been infrequent, mainly in patients with repeated animal contact. We report the first case of pleural empyema in an elderly woman. tends to cause more severe infection because of a biofilm layer which helps in adherence and colonization of smooth surfaces, especially prosthetic devices, shunts, and catheters. The challenging problem even after CoNS isolation and identification is the assessment of their clinical relevance. Major factors that inhibit the penetration of antibiotics is the large-sized effusions/empyema, thickness of pleura, and the nature of antibiotic itself. Source control for septic patients remains the cornerstone of treatment along with optimal antimicrobial coverage. , a coagulase-negative staphylococcus, is emerging as an important cause of virulent infections with high mortality in humans. Given its propensity for multidrug resistance, including vancomycin, there is an imperative for early and accurate identification of the isolate. Despite aggressive treatment, the patient succumbed to her illness.
PubMed: 30405924
DOI: 10.1155/2018/7831284 -
Frontiers in Microbiology 2018The present study explored the possible prebiotic application of potato peel and bamboo shoot extracts for the proliferation of lactic acid bacteria (LAB) from diverse...
The present study explored the possible prebiotic application of potato peel and bamboo shoot extracts for the proliferation of lactic acid bacteria (LAB) from diverse niches and their tolerance ability to simulated gastrointestinal tract (GIT) conditions was also examined. Initially, the complete 16S rDNA sequencing of selected isolates revealed them as (6), (2), and (1). Higher cell densities and rapid pH change were obtained from cultured media supplemented with BS (2%) and PP (2%) as a carbon source. Their higher tolerance and the lowest reducing sugar abilities were obtained for BS at pH 2.5 and 9.0, while at pH 3.5 and 8.0 for PP. The isolates were screened for additional functional and technological properties to harvest the most appropriate starter. The selected isolates harbored promising functional properties such as amylase presence, cell surface hydrophobicity, autoaggregation, proteolytic and lipolytic activity, antifungal action, as well as exopolysaccharide production. On the basis of these attributes, microencapsulated strain K3 was found resistant to gastrointestinal conditions after 2 h, resulting in significantly ( ≤ 0.05) improved survival compared to non-capsulated strain. The current approach presents an interesting economical strategy to modulate LAB through supplementation of plant-derived carbon sources as well as to enhance their survival under GIT.
PubMed: 30233560
DOI: 10.3389/fmicb.2018.02114