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Laboratory Animal Research Aug 2023Skin ulcers, skin dermatitis and skin infections are common phenomena in colonies of laboratory mice and are often found at increased prevalence in certain... (Review)
Review
Skin ulcers, skin dermatitis and skin infections are common phenomena in colonies of laboratory mice and are often found at increased prevalence in certain immunocompromised strains. While in many cases these skin conditions are mild, in other cases they can be severe and lead to animal morbidity. Furthermore, the presence of skin infections and ulcerations can complicate the interpretation of experimental protocols, including those examining immune cell activation. Bacterial species in the genus Staphylococcus are the most common pathogens recovered from skin lesions in mice. In particular, Staphylococcus aureus and Staphylococcus xylosus have both been implicated as pathogens on murine skin. Staphylococcus aureus is a well-known pathogen of human skin, but S. xylosus skin infections in humans have not been described, indicating that there is a species-specific difference in the ability of S. xylosus to serve as a skin pathogen. The aim of this review is to summarize studies that link S. aureus and S. xylosus to skin infections of mice and to describe factors involved in their adherence to tissue and their virulence. We discuss potential differences in mouse and human skin that might underlie the ability of S. xylosus to act as a pathogen on murine skin, but not human skin. Finally, we also describe mouse mutants that have shown increased susceptibility to skin infections with staphylococcal bacteria. These mutants point to pathways that are important in the control of commensal staphylococcal bacteria. The information here may be useful to researchers who are working with mouse strains that are prone to skin infections with staphylococcal bacteria.
PubMed: 37533118
DOI: 10.1186/s42826-023-00169-0 -
Infection and Drug Resistance 2022Drug resistance presents an ever-increasing global public health threat that involves all major microbial pathogens and antimicrobial drugs. Strains that are resistant...
PURPOSE
Drug resistance presents an ever-increasing global public health threat that involves all major microbial pathogens and antimicrobial drugs. Strains that are resistant to multiple drugs pose severe clinical problems and cost lives. However, systematic studies on cross-resistance of have been missing.
METHODS
Here, we investigated various mutations in the sequence of ribosomal proteins involved in cross-resistance. To understand this effect on a molecular basis and to further elucidate the role of cross-resistance, we computationally constructed the 3D model of the large ribosomal subunit from as well as its complexes with both tylosin and florfenicol. Meanwhile, all-atom molecular dynamics simulations was used. In addition, the regulation of protein networks also played an essential role in the development of cross-resistance in .
RESULTS
We discovered that the minimum inhibitory concentration against both tylosin and florfenicol of the mutant strain containing the insertion L22 97KRTSAIN98 changed dramatically. Further, we found that unique structural changes in the β-hairpin of L22 played a central role in this variant in the development of antibiotic resistance in . The regulation of protein networks also played an essential role in the development of cross-resistance in .
CONCLUSION
Our work provides insightful views into the mechanism of resistance that could be useful for the development of the next generation of antibiotics.
PubMed: 36304967
DOI: 10.2147/IDR.S379264 -
International Journal of Molecular... Sep 2023Staphylococci are major causes of infections in mammals. Mammals are colonized by diverse staphylococcal species, often with moderate to strong host specificity, and... (Review)
Review
Staphylococci are major causes of infections in mammals. Mammals are colonized by diverse staphylococcal species, often with moderate to strong host specificity, and colonization is a common source of infection. Staphylococcal infections of animals not only are of major importance for animal well-being but have considerable economic consequences, such as in the case of staphylococcal mastitis, which costs billions of dollars annually. Furthermore, pet animals can be temporary carriers of strains infectious to humans. Moreover, antimicrobial resistance is a great concern in livestock infections, as there is considerable antibiotic overuse, and resistant strains can be transferred to humans. With the number of working antibiotics continuously becoming smaller due to the concomitant spread of resistant strains, alternative approaches, such as anti-virulence, are increasingly being investigated to treat staphylococcal infections. For this, understanding the virulence mechanisms of animal staphylococcal pathogens is crucial. While many virulence factors have similar functions in humans as animals, there are increasingly frequent reports of host-specific virulence factors and mechanisms. Furthermore, we are only beginning to understand virulence mechanisms in animal-specific staphylococcal pathogens. This review gives an overview of animal infections caused by staphylococci and our knowledge about the virulence mechanisms involved.
Topics: Animals; Female; Humans; Virulence; Staphylococcus; Staphylococcal Infections; Anti-Bacterial Agents; Virulence Factors; Mammals; Microbial Sensitivity Tests
PubMed: 37834035
DOI: 10.3390/ijms241914587 -
Microorganisms Dec 2021The biofilm associated protein (Bap) is recognised as the essential component for biofilm formation in V329 and has been predicted as important for other species as...
The biofilm associated protein (Bap) is recognised as the essential component for biofilm formation in V329 and has been predicted as important for other species as well. Although Bap orthologs are also present in most strains, their contribution to biofilm formation has not yet been demonstrated. In this study, different experimental approaches were used to elucidate the effect of Bap on biofilm formation in and the motif structure of two biofilm-forming strains TMW 2.1023 and TMW 2.1523 was compared to Bap of V329. We found that despite an identical structural arrangement into four regions, Bap from differs in key factors to Bap of , i.e., isoelectric point of aggregation prone Region B, protein homology and type of repeats. Disruption of had no effect on aggregation behavior of selected strains and biofilm formation was unaffected (TMW 2.1023) or at best slightly reduced under neutral conditions (TMW 2.1523). Further, we could not observe any typical characteristics of a Bap-positive phenotype such as functional impairment by calcium addition and rough colony morphology on congo red agar (CRA). A dominating role of Bap in cell aggregation and biofilm formation as reported mainly for V329 was not observed. In contrast, this work demonstrates that functions of Bap cannot easily be extrapolated to Bap, which appears as non-essential for biofilm formation in this species. We therefore suggest that biofilm formation in follows different and multifactorial mechanisms.
PubMed: 34946212
DOI: 10.3390/microorganisms9122610 -
STAR Protocols Dec 2022Intratumor microbiota is a dynamic cancer component that can be carried over by metastatic tumor cells to distal organs. This protocol was developed to genetically label...
Intratumor microbiota is a dynamic cancer component that can be carried over by metastatic tumor cells to distal organs. This protocol was developed to genetically label Staphylococcus xylosus and trace the recombinant strain in vivo in the tumor. We optimized the recombination-based gene replacement protocol to insert a GFP-Erythromycin resistant protein (Erm) cassette. The inserted cassette facilitates the tracking of the recombinant strain, allowing a sensitive interrogation of microbial dynamics with high temporal and spatial resolution. For complete details on the use and execution of this protocol, please refer to Fu et al. (2022).
Topics: Staphylococcus; Erythromycin; Proteins
PubMed: 36208450
DOI: 10.1016/j.xpro.2022.101624 -
Foods (Basel, Switzerland) Apr 2022The protease generated from Staphylococcus (S.) xylosus A2, which was isolated from Harbin dry sausages, was purified and characterized. The molecular weight of the...
The protease generated from Staphylococcus (S.) xylosus A2, which was isolated from Harbin dry sausages, was purified and characterized. The molecular weight of the purified protease was approximately 21.5 kDa, and its relative activity reached the highest at pH 6.0 and 50 °C. At pH 4.0−8.0 and temperatures of 20−50 °C, the protease was stable. Its activity was significantly improved by Ca2+ and Zn2+ ions (p < 0.05). The Michaelis constant and maximum velocity of the protease were 2.94 mg/mL and 19.45 U/mL·min, respectively. The thermodynamic parameters analysis suggested that the protease showed better catalytic properties at 40 °C. Moreover, the protease could hydrolyze meat proteins, and obtained hydrolysate is non-cytotoxic to the HEK-293 cells. These findings provide a theoretical basis for understanding the enzymatic characterization of S. xylosus A2 protease and its future application in fermented meat products.
PubMed: 35454681
DOI: 10.3390/foods11081094 -
Journal of Microbiology and... Apr 2022We evaluated the antibiotic susceptibilities, hemolytic activities, and technological properties of 36 strains and 49 strains predominantly isolated from fermented...
We evaluated the antibiotic susceptibilities, hemolytic activities, and technological properties of 36 strains and 49 strains predominantly isolated from fermented soybean foods from Korea. Most of the strains were sensitive to chloramphenicol, erythromycin, gentamycin, kanamycin, lincomycin, oxacillin, tetracycline, and trimethoprim. However, 23 strains exhibited potential phenotypic acquired resistance to erythromycin, lincomycin, and tetracycline. Based on breakpoint values for staphylococci from the Clinical and Laboratory Standards Institute, >30% of the isolates were resistant to ampicillin and penicillin G, but the population distributions in minimum inhibitory concentration tests were clearly different from those expected for acquired resistance. None of the strains exhibited clear α- or β-hemolytic activity. and exhibited salt tolerance on agar medium containing 20% and 22% (w/v) NaCl, respectively. and strains possessed protease and lipase activities, which were affected by the NaCl concentration. Protease activity of was strain-specific, but lipase activity might be a characteristic of both species. This study confirms the potential of both species for use in high-salt soybean fermentation, but the safety and technological properties of strains must be determined to select suitable starter candidates.
Topics: Anti-Bacterial Agents; Erythromycin; Fermented Foods; Food Microbiology; Lincomycin; Lipase; Microbial Sensitivity Tests; Peptide Hydrolases; Sodium Chloride; Glycine max; Staphylococcus; Tetracyclines
PubMed: 35001006
DOI: 10.4014/jmb.2111.11040 -
International Journal of Food... Nov 2023Penicillium nordicum is one of the major producers of ochratoxin A (OTA) in dry-cured ham. Staphylococcus xylosus Sx8 and Staphylococcus equorum Se31 have been...
Penicillium nordicum is one of the major producers of ochratoxin A (OTA) in dry-cured ham. Staphylococcus xylosus Sx8 and Staphylococcus equorum Se31 have been previously proposed as biocontrol agents (BCAs) to prevent the OTA contamination, although their antifungal mode of action has not been established yet. Thus, the aim of this work was to elucidate their mode of action against P. nordicum in a dry-cured ham model system. For this, the effect of live cells, dead cells, and cell-free broth; the nutritional utilisation pattern, niche overlap index (NOI), interactions by dual-culture assays, antifungal effect of volatile compounds, OTA detoxification, and effect on fungal proteome were determined. No fungal growth was observed after 14 days of co-culture with live cells of each staphylococcus at 15 or 20 °C. However, such inhibition was not observed with either dead cells or extracellular extracts. The number of carbon sources utilised by P. nordicum was higher than those used by both cocci at 20 °C, whilst the opposite occurred at 15 °C. According to NOI, nutritional dominance depends on temperature, at 20 °C P. nordicum dominated the niche, but at 15 °C the mould is dominated by the BCAs. The volatile pattern generated by each coccus did not show antifungal effect, and both staphylococci failed to degrade or adsorb OTA. However, in the interaction assay, S. xylosus and S. equorum were able to decrease the fungal growth and its OTA production. In addition, proteomic analyses showed changes in the abundance of proteins related to the cell wall integrity (CWI), carbohydrate metabolism and the biosynthesis of secondary metabolites such as OTA. In conclusion, overall, the antagonistic effects of the two studied cocci against P. nordicum are greater at 15 °C than at 20 °C, being linked to competition for space and nutrients, triggering alterations in CWI pathway, OTA biosynthesis, and carbohydrate metabolism.
Topics: Food Microbiology; Pork Meat; Proteomics; Antifungal Agents; Meat Products; Ochratoxins; Penicillium; Staphylococcus
PubMed: 37523903
DOI: 10.1016/j.ijfoodmicro.2023.110342 -
Frontiers in Microbiology 2022Malondialdehyde (MDA) is one of the most representative reactive carbonyl species (RCSs) produced by lipid oxidation in food. However, the inhibitory effect of MDA on...
Malondialdehyde (MDA) is one of the most representative reactive carbonyl species (RCSs) produced by lipid oxidation in food. However, the inhibitory effect of MDA on microorganisms has received little attention. Thus, the aim of this study was to reveal the antibacterial mechanism of MDA on and isolated from dry-cured fish. The results showed that the minimum inhibitory concentrations (MICs) of MDA on and were 90 μg/ml and 180 μg/ml, respectively. Time-kill curves indicated a concentration-dependent antibacterial activity of MDA. Moreover, cell wall damage, cell membrane depolarization, intracellular adenosine triphosphate (ATP) decline, Ca and Mg leakage, cell morphological destruction and alterations in intracellular biomolecules were observed, which indicated the negative influence of MDA on cell membrane and cellular homeostasis. This study demonstrated the potential antimicrobial properties of MDA and provided theoretical support for the scientific prevention and control of lipid oxidation and microbial contamination in food. This study demonstrated the potential antibacterial properties of MDA and further enriches theoretical studies on the effects of lipid oxidation on microorganisms.
PubMed: 36406445
DOI: 10.3389/fmicb.2022.979388 -
Food Science & Nutrition Aug 2020For decades, lactic acid bacteria has been isolated and selected to be used as starter cultures in meat fermentation for standardization and management of quality of...
For decades, lactic acid bacteria has been isolated and selected to be used as starter cultures in meat fermentation for standardization and management of quality of dry-fermented sausage which constitute a considerable challenge. The aim of this study was to evaluate the effect of strains, isolated from different origins, on qualities of dry-fermented sausages. These last, manufactured with different combinations of starter cultures ( + ), were ripened, using the same raw materials and conditions, for 45 days. Samples were collected during this period, and microbiological, physicochemical, fatty acid profile, and sensorial analyses determined. Lactic acid bacteria were the dominant flora during ripening. A desirable PUFA/SFA ratio, corresponding to 1:1.7 (0.6), was detected after 24 days of maturation in sausages inoculated by BMG 95 and . Sensory analysis showed that fermented sausages manufactured with and had a more desirable odor, flavor, and texture and consequently were preferred overall. In particular, sensory panellists preferred sausages produced with either 23K or BMG 95 when compared to fermented sausage produced with a commercial starter or no starter at all.
PubMed: 32884698
DOI: 10.1002/fsn3.1711