scholarly journals Suppressing Alpha-Hemolysin as Potential Target to Screen of Flavonoids to Combat Bacterial Coinfection

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7577
Author(s):  
Shangwen He ◽  
Qian Deng ◽  
Bingbing Liang ◽  
Feike Yu ◽  
Xiaohan Yu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Hemolytic Activity ◽  
Antibacterial Drugs ◽  
Alpha Hemolysin ◽  
Potential Target ◽  
Bacterial Coinfection ◽  
Host Inflammatory Response ◽  
Rapid Emergence

The rapid emergence of bacterial coinfection caused by cytosolic bacteria has become a huge threat to public health worldwide. Past efforts have been devoted to discover the broad-spectrum antibiotics, while the emergence of antibiotic resistance encourages the development of antibacterial agents. In essence, bacterial virulence is a factor in antibiotic tolerance. However, the discovery and development of new antibacterial drugs and special antitoxin drugs is much more difficult in the antibiotic resistance era. Herein, we hypothesize that antitoxin hemolytic activity can serve as a screening principle to select antibacterial drugs to combat coinfection from natural products. Being the most abundant natural drug of plant origins, flavonoids were selected to assess the ability of antibacterial coinfections in this paper. Firstly, we note that four flavonoids, namely, baicalin, catechin, kaempferol, and quercetin, have previously exhibited antibacterial abilities. Then, we found that baicalin, kaempferol, and quercetin have better inhibitions of hemolytic activity of Hla than catechin. In addition, kaempferol and quercetin, have therapeutic effectivity for the coinfections of Staphylococcus aureus and Pseudomonas aeruginosa in vitro and in vivo. Finally, our results indicated that kaempferol and quercetin therapied the bacterial coinfection by inhibiting S. aureus α-hemolysin (Hla) and reduced the host inflammatory response. These results suggest that antitoxins may play a promising role as a potential target for screening flavonoids to combat bacterial coinfection.

Evaluation of the In Vivo Acute Toxicity and In Vitro Hemolytic and Immunomodulatory Activities of the Moringa oleifera Flower Trypsin Inhibitor (MoFTI)

2020 ◽  
Vol 27 ◽  
Author(s):  
Leydianne Leite de Siqueira Patriota ◽  
Dayane Kelly Dias do Nascimento Santos ◽  
Bárbara Rafaela da Silva Barros ◽  
Lethícia Maria de Souza Aguiar ◽  
Yasmym Araújo Silva ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Trypsin Inhibitor ◽  
Hemolytic Activity ◽  
Moringa Oleifera ◽  
Biological Activities ◽  
Hematological Parameters ◽  
Behavioral Alterations ◽  
Female Mice

Background: Protease inhibitors have been isolated from plants and present several biological activities, including immunomod-ulatory action. Objective: This work aimed to evaluate a Moringa oleifera flower trypsin inhibitor (MoFTI) for acute toxicity in mice, hemolytic activity on mice erythrocytes and immunomodulatory effects on mice splenocytes. Methods: The acute toxicity was evaluated using Swiss female mice that received a single dose of the vehicle control or MoFTI (300 mg/kg, i.p.). Behavioral alterations were observed 15–240 min after administration, and survival, weight gain, and water and food consumption were analyzed daily. Organ weights and hematological parameters were analyzed after 14 days. Hemolytic activity of MoFTI was tested using Swiss female mice erythrocytes. Splenocytes obtained from BALB/c mice were cultured in the absence or presence of MoFTI for the evaluation of cell viability and proliferation. Mitochondrial membrane potential (ΔΨm) and reactive oxygen species (ROS) levels were also determined. Furthermore, the culture supernatants were analyzed for the presence of cytokines and nitric oxide (NO). Results: MoFTI did not cause death or any adverse effects on the mice except for abdominal contortions at 15–30 min after administration. MoFTI did not exhibit a significant hemolytic effect. In addition, MoFTI did not induce apoptosis or necrosis in splenocytes and had no effect on cell proliferation. Increases in cytosolic and mitochondrial ROS release, as well as ΔΨm reduction, were observed in MoFTI-treated cells. MoFTI was observed to induce TNF-α, IFN-γ, IL-6, IL-10, and NO release. Conclusion: These results contribute to the ongoing evaluation of the antitumor potential of MoFTI and its effects on other immunological targets.

scholarly journals Reversal of Azole Resistance inCandida albicansby Sulfa Antibacterial Drugs

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Hassan E. Eldesouky ◽  
Abdelrahman Mayhoub ◽  
Tony R. Hazbun ◽  
Mohamed N. Seleem
Keyword(s):  
Treatment Options ◽  
Antifungal Drugs ◽  
Infection Model ◽  
Azole Resistance ◽  
Global Public Health ◽  
Sulfa Drugs ◽  
Antibacterial Drugs ◽  
Content Type

ABSTRACTInvasive candidiasis presents an emerging global public health challenge due to the emergence of resistance to the frontline treatment options, such as fluconazole. Hence, the identification of other compounds capable of pairing with fluconazole and averting azole resistance would potentially prolong the clinical utility of this important group. In an effort to repurpose drugs in the field of antifungal drug discovery, we explored sulfa antibacterial drugs for the purpose of reversing azole resistance inCandida. In this study, we assembled and investigated a library of 21 sulfa antibacterial drugs for their ability to restore fluconazole sensitivity inCandida albicans. Surprisingly, the majority of assayed sulfa drugs (15 of 21) were found to exhibit synergistic relationships with fluconazole by checkerboard assay with fractional inhibitory concentration index (ΣFIC) values ranging from <0.0312 to 0.25. Remarkably, five sulfa drugs were able to reverse azole resistance in a clinically achievable range. The structure-activity relationships (SARs) of the amino benzene sulfonamide scaffold as antifungal agents were studied. We also identified the possible mechanism of the synergistic interaction of sulfa antibacterial drugs with azole antifungal drugs. Furthermore, the ability of sulfa antibacterial drugs to inhibitCandidabiofilm by 40%in vitrowas confirmed. In addition, the effects of sulfa-fluconazole combinations onCandidagrowth kinetics and efflux machinery were explored. Finally, using aCaenorhabditis elegansinfection model, we demonstrated that the sulfa-fluconazole combination does possess potent antifungal activityin vivo, reducingCandidain infected worms by ∼50% compared to the control.

scholarly journals Clinical extended-spectrum beta-lactamase antibiotic resistance plasmids have diverse transfer rates and can spread in the absence of antibiotic selection

2019 ◽  
Author(s):  
Fabienne Benz ◽  
Jana S. Huisman ◽  
Erik Bakkeren ◽  
Joana A. Herter ◽  
Tanja Stadler ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Conjugative Transfer ◽  
Beta Lactamase ◽  
Extended Spectrum Beta Lactamase ◽  
Extended Spectrum ◽  
Resistance Plasmids ◽  
Serovar Typhimurium ◽  
Spreading Potential

AbstractHorizontal gene transfer, mediated by conjugative plasmids, is a major driver of the global spread of antibiotic resistance. However, the relative contributions of factors that underlie the spread of clinically relevant plasmids are unclear. Here, we quantified conjugative transfer dynamics of Extended Spectrum Beta-Lactamase (ESBL) producing plasmids in the absence of antibiotics. We showed that clinical Escherichia coli strains natively associated with ESBL-plasmids conjugate efficiently with three distinct E. coli strains and one Salmonella enterica serovar Typhimurium strain, reaching final transconjugant frequencies of up to 1% within 24 hours in vitro. The variation of final transconjugant frequencies varied among plasmids, donors and recipients and was better explained by variation in conjugative transfer efficiency than by variable clonal expansion. We identified plasmid-specific genetic factors, specifically the presence/absence of transfer genes, that influenced final transconjugant frequencies. Finally, we investigated plasmid spread within the mouse intestine, demonstrating qualitative agreement between plasmid spread in vitro and in vivo. This suggests a potential for the prediction of plasmid spread in the gut of animals and humans, based on in vitro testing. Altogether, this may allow the identification of resistance plasmids with high spreading potential and help to devise appropriate measures to restrict their spread.

scholarly journals Dopamine receptor D1- and D2-agonists do not spark brown adipose tissue thermogenesis in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Francesca-Maria Raffaelli ◽  
Julia Resch ◽  
Rebecca Oelkrug ◽  
K. Alexander Iwen ◽  
Jens Mittag
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Dopamine Receptor ◽  
Ex Vivo ◽  
Potential Target ◽  
D2 Agonist ◽  
Obesity And Diabetes ◽  
Brown Adipose

AbstractBrown adipose tissue (BAT) thermogenesis is considered a potential target for treatment of obesity and diabetes. In vitro data suggest dopamine receptor signaling as a promising approach; however, the biological relevance of dopamine receptors in the direct activation of BAT thermogenesis in vivo remains unclear. We investigated BAT thermogenesis in vivo in mice using peripheral administration of D1-agonist SKF38393 or D2-agonist Sumanirole, infrared thermography, and in-depth molecular analyses of potential target tissues; and ex vivo in BAT explants to identify direct effects on key thermogenic markers. Acute in vivo treatment with the D1- or D2-agonist caused a short spike or brief decrease in BAT temperature, respectively. However, repeated daily administration did not induce lasting effects on BAT thermogenesis. Likewise, neither agonist directly affected Ucp1 or Dio2 mRNA expression in BAT explants. Taken together, the investigated agonists do not seem to exert lasting and physiologically relevant effects on BAT thermogenesis after peripheral administration, demonstrating that D1- and D2-receptors in iBAT are unlikely to constitute targets for obesity treatment via BAT activation.

scholarly journals Phage steering of antibiotic-resistance evolution in the bacterial pathogen, Pseudomonas aeruginosa

2020 ◽  
Vol 2020 (1) ◽  
pp. 148-157 ◽  
Author(s):  
James Gurney ◽  
Léa Pradier ◽  
Joanne S Griffin ◽  
Claire Gougat-Barbera ◽  
Benjamin K Chan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Bacterial Pathogen ◽  
Antibiotic Sensitivity ◽  
Resistant Bacteria ◽  
Phage Resistance ◽  
Antibiotic Resistant ◽  
Trade Off

Abstract Background and objectives Antimicrobial resistance is a growing global concern and has spurred increasing efforts to find alternative therapeutics. Bacteriophage therapy has seen near constant use in Eastern Europe since its discovery over a century ago. One promising approach is to use phages that not only reduce bacterial pathogen loads but also select for phage resistance mechanisms that trade-off with antibiotic resistance—so called ‘phage steering’. Methodology Recent work has shown that the phage OMKO1 can interact with efflux pumps and in so doing select for both phage resistance and antibiotic sensitivity of the pathogenic bacterium Pseudomonas aeruginosa. We tested the robustness of this approach to three different antibiotics in vitro (tetracycline, erythromycin and ciprofloxacin) and one in vivo (erythromycin). Results We show that in vitro OMKO1 can reduce antibiotic resistance of P. aeruginosa (Washington PAO1) even in the presence of antibiotics, an effect still detectable after ca.70 bacterial generations in continuous culture with phage. Our in vivo experiment showed that phage both increased the survival times of wax moth larvae (Galleria mellonella) and increased bacterial sensitivity to erythromycin. This increased antibiotic sensitivity occurred both in lines with and without the antibiotic. Conclusions and implications Our study supports a trade-off between antibiotic resistance and phage sensitivity. This trade-off was maintained over co-evolutionary time scales even under combined phage and antibiotic pressure. Similarly, OMKO1 maintained this trade-off in vivo, again under dual phage/antibiotic pressure. Our findings have implications for the future clinical use of steering in phage therapies. Lay Summary: Given the rise of antibiotic-resistant bacterial infection, new approaches to treatment are urgently needed. Bacteriophages (phages) are bacterial viruses. The use of such viruses to treat infections has been in near-continuous use in several countries since the early 1900s. Recent developments have shown that these viruses are not only effective against routine infections but can also target antibiotic resistant bacteria in a novel, unexpected way. Similar to other lytic phages, these so-called ‘steering phages’ kill the majority of bacteria directly. However, steering phages also leave behind bacterial variants that resist the phages, but are now sensitive to antibiotics. Treatment combinations of these phages and antibiotics can now be used to greater effect than either one independently. We evaluated the impact of steering using phage OMKO1 and a panel of three antibiotics on Pseudomonas aeruginosa, an important pathogen in hospital settings and in people with cystic fibrosis. Our findings indicate that OMKO1, either alone or in combination with antibiotics, maintains antibiotic sensitivity both in vitro and in vivo, giving hope that phage steering will be an effective treatment option against antibiotic-resistant bacteria.

scholarly journals Tridecaptin M, a New Variant Discovered in Mud Bacterium, Shows Activity against Colistin- and Extremely Drug-ResistantEnterobacteriaceae

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Manoj Jangra ◽  
Manpreet Kaur ◽  
Rushikesh Tambat ◽  
Rohit Rana ◽  
Sushil K. Maurya ◽  
...  
Keyword(s):  
Hemolytic Activity ◽  
World Health ◽  
Fourth Generation ◽  
Infection Model ◽  
Drug Resistant ◽  
Content Type ◽  
Extensively Drug Resistant ◽  
New Variant

ABSTRACTThe World Health Organization has categorized the Gram-negative superbugs, which are inherently impervious to many antibiotics, as critical priority pathogens due to the lack of effective treatments. The breach in our last-resort antibiotic (i.e., colistin) by extensively drug-resistant and pan-drug-resistantEnterobacteriaceaestrains demands the immediate development of new therapies. In the present study, we report the discovery of tridecaptin M, a new addition to the family, and its potential against colistin-resistantEnterobacteriaceae in vitroandin vivo. Also, we performed mode-of-action studies using various fluorescent probes and studied the hemolytic activity and mammalian cytotoxicity in two cell lines. Tridecaptin M displayed strong antibacterial activity (MICs of 2 to 8 μg ml−1) against clinical strains ofKlebsiella pneumoniae(which were resistant to colistin, carbapenems, third- and fourth-generation cephalosporins, fluoroquinolones, fosfomycin, and other antibiotics) andmcr-1-positiveEscherichia colistrains. Unlike polymyxins, tridecaptin M did not permeabilize the outer membrane or cytoplasmic membrane. It blocked ATP synthesis in bacteria by dissipating the proton motive force. The compound exhibited negligible acquired resistance, lowin vitrocytotoxicity and hemolytic activity, and no significant acute toxicity in mice. It also showed promising efficacy in a thigh infection model of colistin-resistantK. pneumoniae. Altogether, these results demonstrate the future prospects of this class of antibiotics to address the unmet medical need to circumvent colistin resistance in extensively drug-resistantEnterobacteriaceaeinfections. The work also emphasizes the importance of natural products in our shrunken drug discovery pipeline.

scholarly journals Intra- and Interspecies Conjugal Transfer of Tn916-Like Elements from Lactococcus lactis In Vitro and In Vivo

2009 ◽  
Vol 75 (19) ◽  
pp. 6352-6360 ◽  
Author(s):  
Joanna Boguslawska ◽  
Joanna Zycka-Krzesinska ◽  
Andrea Wilcks ◽  
Jacek Bardowski
Keyword(s):  
Antibiotic Resistance ◽  
Lactococcus Lactis ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Raw Milk ◽  
M Gene ◽  
Transfer Resistance

ABSTRACT Tetracycline-resistant Lactococcus lactis strains originally isolated from Polish raw milk were analyzed for the ability to transfer their antibiotic resistance genes in vitro, using filter mating experiments, and in vivo, using germfree rats. Four of six analyzed L. lactis isolates were able to transfer tetracycline resistance determinants in vitro to L. lactis Bu2-60, at frequencies ranging from 10−5 to 10−7 transconjugants per recipient. Three of these four strains could also transfer resistance in vitro to Enterococcus faecalis JH2-2, whereas no transfer to Bacillus subtilis YBE01, Pseudomonas putida KT2442, Agrobacterium tumefaciens UBAPF2, or Escherichia coli JE2571 was observed. Rats were initially inoculated with the recipient E. faecalis strain JH2-2, and after a week, the L. lactis IBB477 and IBB487 donor strains were introduced. The first transconjugants were detected in fecal samples 3 days after introduction of the donors. A subtherapeutic concentration of tetracycline did not have any significant effect on the number of transconjugants, but transconjugants were observed earlier in animals dosed with this antibiotic. Molecular analysis of in vivo transconjugants containing the tet(M) gene showed that this gene was identical to tet(M) localized on the conjugative transposon Tn916. Primer-specific PCR confirmed that the Tn916 transposon was complete in all analyzed transconjugants and donors. This is the first study showing in vivo transfer of a Tn916-like antibiotic resistance transposon from L. lactis to E. faecalis. These data suggest that in certain cases food lactococci might be involved in the spread of antibiotic resistance genes to other lactic acid bacteria.

scholarly journals Characterization of the Global Stabilizing Substitution A77V and Its Role in the Evolution of CTX-M β-Lactamases

2015 ◽  
Vol 59 (11) ◽  
pp. 6741-6748 ◽  
Author(s):  
Meha P. Patel ◽  
Bartlomiej G. Fryszczyn ◽  
Timothy Palzkill
Keyword(s):  
Antibiotic Resistance ◽  
Adaptive Mutation ◽  
Common Mechanism ◽  
Antibiotic Hydrolysis ◽  
The Stability ◽  
Kinetics Of ◽  
M 14

ABSTRACTThe widespread use of oxyimino-cephalosporin antibiotics drives the evolution of the CTX-M family of β-lactamases that hydrolyze these drugs and confer antibiotic resistance. Clinically isolated CTX-M enzymes carrying the P167S or D240G active site-associated adaptive mutation have a broadened substrate profile that includes the oxyimino-cephalosporin antibiotic ceftazidime. The D240G substitution is known to reduce the stability of CTX-M-14 β-lactamase, and the P167S substitution is shown here to also destabilize the enzyme. Proteins are marginally stable entities, and second-site mutations that stabilize the enzyme can offset a loss in stability caused by mutations that enhance enzyme activity. Therefore, the evolution of antibiotic resistance enzymes can be dependent on the acquisition of stabilizing mutations. The A77V substitution is present in CTX-M extended-spectrum β-lactamases (ESBLs) from a number of clinical isolates, suggesting that it may be important in the evolution of antibiotic resistance in this family of β-lactamases. In this study, the effects of the A77V substitution in the CTX-M-14 model enzyme were characterized with regard to the kinetic parameters for antibiotic hydrolysis as well as enzyme expression levelsin vivoand protein stabilityin vitro. The A77V substitution has little effect on the kinetics of oxyimino-cephalosporin hydrolysis, but it stabilizes the CTX-M enzyme and compensates for the loss of stability resulting from the P167S and D240G mutations. The acquisition of global stabilizing mutations, such as A77V, is an important feature in β-lactamase evolution and a common mechanism in protein evolution.

Transfer of antibiotic resistance determinants between lactobacilli isolates from the gastrointestinal tract of chicken

2012 ◽  
Vol 3 (2) ◽  
pp. 137-144 ◽  
Author(s):  
F. Vieira de Souza ◽  
R. Roque ◽  
J.L. Silva Moreira ◽  
M. Resende de Souza ◽  
J.R. Nicoli ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gastrointestinal Tract ◽  
Broiler Chickens ◽  
Lactobacillus Reuteri ◽  
Multi Drug Resistance ◽  
Bacterial Strains ◽  
Genetic Traits ◽  
In Vivo Experiments

The aim of this study was to assess the potential horizontal transfer of genetic traits for antibiotic resistance between lactobacilli isolated from the chicken gut, both in vitro and in vivo. Thirty-seven Lactobacillus spp. strains isolated from the gizzard, small and large intestines and caeca of free-range broiler chickens showed multi-drug resistance as assessed by disc diffusion assays. The minimum inhibitory concentration (MIC) for vancomycin, tetracycline, erythromycin and chloramphenicol was determined in De Man, Rogosa and Sharpe broth in a microplate assay. Almost all the lactobacilli isolates were resistant to vancomycin (except strains belonging to the Lactobacillus acidophilus group) and to tetracycline (MIC≥128 μg/ml). Only five strains were resistant to erythromycin, and six to chloramphenicol. The transfer rate in filter mating experiments performed using L. acidophilus strain 4M14E (EmR), Lactobacillus vaginalis strain 5M14E (CmR), Lactobacillus salivarius strain 5C14C (EmR), and the 4G14L and 3C14C strains of Lactobacillus reuteri (CmR) showed a frequency of approximately 1×104 cfu/ml of double-resistant transconjugants for the different combinations. The exception was the L. salivarius 5C14C (EmR) and L. vaginalis 5M14E (CmR) mating combination, which produced no transconjugants. In vivo experiments performed in gnotobiotic mice by mating L. acidophilus 4M14E (EmR) with L. reuteri 3C14C (CmR), L. reuteri 4G14L (CmR) or L. vaginalis 5M14E (CmR) resulted in transconjugants at 3.95±0.29, 3.16±0.33, and 4.55±1.52 log10 cfu/g of faeces, respectively. Taken together, these data suggest that genetic exchange may occur between native bacterial strains within the gastrointestinal tract of chickens, which might maintain a dynamic gene pool conferring antibiotic resistance upon indigenous microbiota components, even in the absence of the pathogens. This possibility must be taken into account as a complementary criterion when lactobacilli are screened for probiotic use.

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