• MeSH
• antibakteriální látky biosyntéza   MeSH
• fermentace MeSH

Streptomycetes are soil microorganisms with the potential to produce a broad spectrum of secondary metabolities. The production of antibiotics is accompanied by a decrease in protein synthesis, which raises the question of how these bacteria survived the transition from the primary to the secondary metabolism. Translating ribosomes incapable to properly elongate or terminate polypeptide chain activate bacterial trans-translation system. Abundance and stability of the tmRNA during growth of Streptomyces collinus and Streptomyces griseus producing kirromycin and streptomycin, respectively, was analysed. The level of tmRNA is mostly proportional to the activity of the translational system. We demonstrate that the addition of sub-inhibitory concentrations of produced antibiotics to the cultures from the beginning of the exponential phase of growth leads to an increase in tmRNA levels and to an incorporation of amino acids into the tag-peptides at trans-translation of stalled ribosomes. These findings suggest that produced antibiotics induce tmRNA that facilitate reactivation of stalled complex of ribosomes and maintain viability. The effect of antibiotics that inhibit the cell-wall turnover, DNA, RNA or protein synthesis on the level of tmRNA was examined. Antibiotics interfering with ribosomal target sites are more effective at stimulation of the tmRNA level in streptomycetes examined than those affecting the synthesis of DNA, RNA or the cell wall.

• MeSH
• antibakteriální látky biosyntéza   MeSH
• bakteriální RNA chemie   genetika   metabolismus   MeSH
• proteosyntéza MeSH
• ribozomy chemie   genetika   metabolismus   MeSH
• stabilita RNA MeSH
• Streptomyces griseus genetika   růst a vývoj   metabolismus   MeSH
• Streptomyces genetika   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The host is the main environment for bacteria, and they also expose to many antibiotics during the treatment of infectious diseases in host body. In this study, it was aimed to investigate possible changes in growth rate and expression levels of three virulence genes (foc/foc, cnf1, and usp) in a uropathogenic E. coli standard strain within the presence of ciprofloxacin, nitrofurantoin, and trimethoprim-sulfamethoxazole. The UPEC C7 strain was grown on tryptic soy broth-TSB (control), TSB + ciprofloxacin, TSB + nitrofurantoin, and TSB + trimethoprim-sulfamethoxazole for determination of both growth rate and gene expression level. Antibiotics were added according to their sub-minimal inhibition concentrations. E-test was used to determine MIC values of antibiotics. Growth changes were measured in absorbance 600 nm during 24-h period. Total RNA isolations were performed after incubation for 24 h at 37 °C. Gene expression levels were determined by quantitative PCR. Tukey's post hoc test was used for statistical analysis. According to absorbance values, it has been shown that only ciprofloxacin and trimethoprim-sulfamethoxazole have lead significant decrease on growth rate. We also detected statistically significant differences in each gene expression levels for all antibiotics via relative quantification analysis. Fold changes in gene expression was found 0.65, 1.42, 0.23 for foc/foc gene; 0.01, 0.01, 2.84 for cnf1 gene; and 0.1, 0.01, 0.01 for usp gene in the presence of ciprofloxacin, nitrofurantoin, and trimethoprim/sulfamethoxazole, respectively. This investigation has shown that antibiotics can play a role as an environmental factor which may determine the pathogenicity of bacteria in vivo.

• MeSH
• antibakteriální látky metabolismus   farmakologie   MeSH
• bakteriální proteiny genetika   MeSH
• bakteriální toxiny genetika   MeSH
• ciprofloxacin metabolismus   farmakokinetika   MeSH
• kombinace léků trimethoprim a sulfamethoxazol metabolismus   farmakologie   MeSH
• lidé MeSH
• membránové transportní proteiny genetika   MeSH
• mikrobiální testy citlivosti MeSH
• nitrofurantoin metabolismus   farmakologie   MeSH
• proteiny z Escherichia coli genetika   MeSH
• regulace genové exprese u bakterií fyziologie   MeSH
• uropatogenní Escherichia coli účinky léků   genetika   růst a vývoj   MeSH
• virulence genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Bacterial cell wall peptidoglycan is essential, maintaining both cellular integrity and morphology, in the face of internal turgor pressure. Peptidoglycan synthesis is important, as it is targeted by cell wall antibiotics, including methicillin and vancomycin. Here, we have used the major human pathogen Staphylococcus aureus to elucidate both the cell wall dynamic processes essential for growth (life) and the bactericidal effects of cell wall antibiotics (death) based on the principle of coordinated peptidoglycan synthesis and hydrolysis. The death of S. aureus due to depletion of the essential, two-component and positive regulatory system for peptidoglycan hydrolase activity (WalKR) is prevented by addition of otherwise bactericidal cell wall antibiotics, resulting in stasis. In contrast, cell wall antibiotics kill via the activity of peptidoglycan hydrolases in the absence of concomitant synthesis. Both methicillin and vancomycin treatment lead to the appearance of perforating holes throughout the cell wall due to peptidoglycan hydrolases. Methicillin alone also results in plasmolysis and misshapen septa with the involvement of the major peptidoglycan hydrolase Atl, a process that is inhibited by vancomycin. The bactericidal effect of vancomycin involves the peptidoglycan hydrolase SagB. In the presence of cell wall antibiotics, the inhibition of peptidoglycan hydrolase activity using the inhibitor complestatin results in reduced killing, while, conversely, the deregulation of hydrolase activity via loss of wall teichoic acids increases the death rate. For S. aureus, the independent regulation of cell wall synthesis and hydrolysis can lead to cell growth, death, or stasis, with implications for the development of new control regimes for this important pathogen.

• MeSH
• antibakteriální látky farmakologie   MeSH
• antiinfekční látky metabolismus   farmakologie   MeSH
• bakteriální proteiny metabolismus   MeSH
• buněčná stěna metabolismus   fyziologie   MeSH
• homeostáza MeSH
• kyseliny teichoové metabolismus   MeSH
• methicilin farmakologie   MeSH
• N-acetylmuramoyl-L-alaninamidasa metabolismus   MeSH
• peptidoglykan metabolismus   MeSH
• stafylokokové infekce mikrobiologie   MeSH
• Staphylococcus aureus růst a vývoj   metabolismus   MeSH
• vankomycin farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Bacteria are associated with the gut, fat bodies and reproductive organs of stored product mites (Acari: Astigmata). The mites are pests due to the production of allergens. Addition of antibiotics to diets can help to characterize the association between mites and bacteria. METHODOLOGY AND PRINCIPAL FINDINGS: Ampicillin, neomycin and streptomycin were added to the diets of mites and the effects on mite population growth (Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae) and associated bacterial community structure were assessed. Mites were treated by antibiotic supplementation (1 mg g(-1) of diet) for 21 days and numbers of mites and bacterial communities were analyzed and compared to the untreated control. Bacterial quantities, determined by real-time PCR, significantly decreased in antibiotic treated specimens from 5 to 30 times in A. siro and T. putrescentiae, while no decline was observed in L. destructor. Streptomycin treatment eliminated Bartonella-like bacteria in the both A. siro and T. putrescentiae and Cardinium in T. putrescentiae. Solitalea-like bacteria proportion increased in the communities of neomycin and streptomycin treated A. siro specimens. Kocuria proportion increased in the bacterial communities of ampicillin and streptomycin treated A. siro and neomycin and streptomycin treated L. destructor. CONCLUSIONS/SIGNIFICANCE: The work demonstrated the changes of mite associated bacterial community under antibiotic pressure in pests of medical importance. Pre-treatment of mites by 1 mg g(-1) antibiotic diets improved mite fitness as indicated accelerated population growth of A. siro pretreated streptomycin and neomycin and L. destructor pretreated by neomycin. All tested antibiotics supplemented to diets caused the decrease of mite growth rate in comparison to the control diet.

• MeSH
• Acaridae účinky léků   růst a vývoj   mikrobiologie   MeSH
• ampicilin farmakologie   MeSH
• antibakteriální látky farmakologie   MeSH
• Bacteria genetika   MeSH
• hustota populace MeSH
• mikrobiální společenstva účinky léků   MeSH
• neomycin farmakologie   MeSH
• RNA ribozomální 16S MeSH
• streptomycin farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pterostilbene (PTE) is a naturally occurring compound originally isolated from Pterocarpus spp. It has been widely used in traditional Indian medicine and later discovered to have various beneficial pharmacological effects such as antioxidant properties, hypoglycaemic or antitumor, and antimicrobial activity. This work is focused on demonstrating PTE synergistic effect with erythromycin and tetracycline to reduce their needed effective concentration for suppression of Staphylococcus epidermidis planktonic cells growth and biofilm formation. The secondary aim is to find these combinations effect on the production of its virulence factors. PTE was found to be effective in inhibition of its planktonic cells with MIC80 values 25-37.5 mg l-1. Simultaneously, it decreased the metabolic activity of biofilm cells and was especially effective on a clinical isolate (MBIC80 = 35 mg l-1) in contrast to the conventional antibiotics. In combination, PTE helped the antibiotics to overcome the tolerance of S. epidermidis biofilm cells (5 mg l-1 of each antibiotic with 49 mg l-1 PTE caused more than 85% inhibition of metabolic activity). It permeabilized cytoplasmic membrane of S. epidermidis cells and altered their surface hydrophobicity. Therefore, PTE has a great potential to enhance antibiotics action in the treatment of infections caused by this pathogen.

• MeSH
• antibakteriální látky * farmakologie   MeSH
• biofilmy MeSH
• faktory virulence MeSH
• mikrobiální testy citlivosti MeSH
• Staphylococcus epidermidis * MeSH
• stilbeny MeSH
• Publikační typ
• časopisecké články MeSH

Ginkgo biloba has long been used in traditional Chinese medicine. In this study, ginkgoneolic acid, a kind of compound extracted from G. biloba, was investigated for its effects on growth, acid production, adherence, biofilm formation, and biofilm morphology of Streptococcus mutans. The results showed that ginkgoneolic acid inhibited not only the growth of S. mutans planktonic cells at minimum inhibitory concentration (MIC) of 4 μg/mL and minimum bactericidal concentration (MBC) of 8 μg/mL but also the acid production and adherence to saliva-coated hydroxyapatite of S. mutans at sub-MIC concentration. In addition, this agent was effective in inhibiting the biofilm formation of S. mutans (MBIC(50) = 4 μg/mL), and it reduced 1-day-developed biofilm of S. mutans by 50 % or more at low concentration (MBRC(50) = 32 μg/mL). Furthermore, the present study demonstrated that ginkgoneolic acid disrupted biofilm integrity effectively. These findings suggest that ginkgoneolic acid is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.

• MeSH
• antibakteriální látky izolace a purifikace   farmakologie   MeSH
• bakteriální adheze účinky léků   MeSH
• biofilmy růst a vývoj   MeSH
• Ginkgo biloba chemie   MeSH
• kyseliny karboxylové metabolismus   MeSH
• mikrobiální testy citlivosti MeSH
• mikrobiální viabilita účinky léků   MeSH
• rostlinné extrakty izolace a purifikace   farmakologie   MeSH
• sliny mikrobiologie   MeSH
• Streptococcus mutans účinky léků   růst a vývoj   metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Aquaculture is the fastest growing food-production sector, and common carp (Cyprinus carpio) is one of the most cultivated fish species in the world. Due to its intrinsic characteristics, fish meat is highly susceptible to microbiological spoilage. Pseudomonas and Shewanella are the primary and secondary occurring microbiota during storage of fish meat, with significant contribution to spoilage with the formation of hydrolytic enzymes (lipases and proteases). RESULTS: With in vitro testing, we show that rosemary extract (Inolens4), buffered vinegar and their combination (SyneROX) exhibit antimicrobial effects against P. fragi, P. psychrophila, S. putrefaciens and S. xiaemensis at concentrations of 3.13 and 1.56 mg mL-1 . The combination was the most effective in inhibiting growth of selected bacteria in food model, and production of lipases and proteases during 9 days at 5 °C. In situ testing of antimicrobial dip treatment of carp meat determined that aerobic mesophilic, total psychrotrophic, Pseudomonas and hydrogen sulfide producer counts were reduced in all treatments, with the most prominent influence being shown by the combination and buffered vinegar. CONCLUSIONS: Our study highlights the importance of a multilevel assessment of the antimicrobial potential of biopreservatives under conditions comparable to those of the selected food. Investigation with bacteria and food model provided coherent and consistent data for the evaluation of the antimicrobial potential for carp meat. Combination of buffered vinegar (as active antimicrobial) and rosemary extract, with well-known and researched antioxidant properties but low in situ antimicrobial activity, represents a good potential for combined effect in preservation of fish meat. © 2020 Society of Chemical Industry.

• MeSH
• antibakteriální látky farmakologie   MeSH
• chuť MeSH
• kapři mikrobiologie   MeSH
• konzervace potravin MeSH
• kyselina octová antagonisté a inhibitory   MeSH
• mikrobiální testy citlivosti MeSH
• potrava z moře (živočišná) mikrobiologie   MeSH
• potravinářská mikrobiologie MeSH
• Pseudomonas účinky léků   růst a vývoj   MeSH
• rostlinné extrakty chemie   MeSH
• rozmarýn chemie   MeSH
• Shewanella účinky léků   růst a vývoj   MeSH
• sulfan analýza   MeSH
• vodní hospodářství MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Conventional chemical antiseptics used for treatment of oral infections often produce side-effects, which restrict their long-term use. Plants are considered as perspective sources of novel natural antiseptics. However, little is still known about their inhibitory properties against oral pathogens. The objective of this study was to test in vitro antimicrobial activities of generally recognized as safe (GRAS) species against planktonic cultures of cariogenic, periodontal and candidal microorganisms and identify active compounds of the most active extracts. Growth-inhibitory effects of ethanol extracts from 109 GRAS plant species, six Humulus lupulus cultivars and two hop supercritical CO2 extracts were evaluated using broth microdilution method. The chemical analysis was done through high-performance liquid chromatography. Best results were obtained for supercritical CO2 and ethanol extracts of H. lupulus with minimum inhibitory concentrations (MIC) ≥8 μg/mL and ≥16 μg/mL, respectively. The chemical analysis of supercritical CO2H. lupulus extracts revealed that α- and β-acids were their main constituents. Capsicum annuum and Capsicum frutescens showed antibacterial effect against Streptococcus sobrinus and Streptococcus salivarius (MIC=64-128 μg/mL). These strains were further inhibited by Zanthoxylum clava-herculis (MIC=64-128 μg/mL) and Myristica fragrans (both MIC≥128 μg/mL). The latter also exhibited antimicrobial activity against Fusobacterium nucleatum (MIC=64 μg/mL). Punica granatum possessed inhibitory effects against Candida albicans (MIC=128 μg/mL) and F. nucleatum (MIC=64 μg/mL). The results indicate that supercritical CO2H. lupulus extracts together with ethanol extracts of C. annuum, C. frutescens, M. fragrans, P. granatum and Z. clava-herculis are promising materials for further investigation on new antiseptic agents of oral care products.

• MeSH
• antibakteriální látky chemie   MeSH
• Candida albicans účinky léků   MeSH
• Capsicum chemie   MeSH
• ethanol MeSH
• Fusobacterium nucleatum účinky léků   MeSH
• Humulus chemie   MeSH
• mikrobiální testy citlivosti MeSH
• Myristica chemie   MeSH
• rostlinné extrakty chemie   MeSH
• Streptococcus sobrinus účinky léků   MeSH
• Zanthoxylum chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In total, 26 natural compounds of various chemical classes (flavonoids, alkaloids, terpenoids) and 19 crude extracts from selected plants were tested in vitro for antibacterial activity against three strains of P. larvae, the causal agent of American Foulbrood Disease of honey bees (AFB) by the broth microdilution method. Among the individual substances, sanguinarine (MIC 4 microg/ml), followed by thymoquinone, capsaicin, trans-2-hexenal and nordihydroguaiaretic acid (MIC 4-32 microg/ml) possessed the strongest antibacterial effect. In case of extracts, common hop (Humulus lupulus L.) and myrtle (Myrtus communis L.) methanolic-dichloromethane extracts exhibited the highest growth-inhibitory effect with MICs ranging from 2 to 8 microg/ml. Acute oral toxicity of the most active natural products was determined on adult honey bees, showing them as non-toxic at concentrations as high as 100 microg peer bee. Our study leads to identification of highly potent natural products effective against AFB in vitro with very low MICs compared to those reported in literature, low toxicity to adult honey bees and commercial availability suggesting them as perspective, low cost and consumer-acceptable agents for control of AFB.

• MeSH
• aldehydy farmakologie   MeSH
• alkaloidy farmakologie   MeSH
• antibakteriální látky farmakologie   MeSH
• benzochinony farmakologie   MeSH
• benzofenantridiny farmakologie   MeSH
• flavonoidy farmakologie   MeSH
• isochinoliny farmakologie   MeSH
• kapsaicin farmakologie   MeSH
• kyselina nordihydroguaiaretová farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• Paenibacillus účinky léků   růst a vývoj   MeSH
• rostlinné extrakty farmakologie   MeSH
• terpeny farmakologie   MeSH
• včely účinky léků   mikrobiologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH