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Frontiers in Cellular and Infection... 2024Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant , particularly those that are carbapenem resistant. CZA resistance in producing PER, a class A...
INTRODUCTION
Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant , particularly those that are carbapenem resistant. CZA resistance in producing PER, a class A extended-spectrum β-lactamase, has been well documented . However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing clinical isolates that were ceftazidime and/or carbapenem non-susceptible.
METHODS
Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics.
RESULTS
Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried . One isolate carried but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the evolved isolate.
DISCUSSION
PER-3-producing ST309 is a successful multidrug-resistant clone with gene implicated in resistance to CZA and other β-lactams.
Topics: Ceftazidime; Pseudomonas aeruginosa; Azabicyclo Compounds; Microbial Sensitivity Tests; Humans; Drug Combinations; beta-Lactamases; Anti-Bacterial Agents; Pseudomonas Infections; Bacterial Proteins; Drug Resistance, Multiple, Bacterial; Chile; Whole Genome Sequencing; Mutation
PubMed: 38903939
DOI: 10.3389/fcimb.2024.1410834 -
Frontiers in Immunology 2024Extracellular vesicles (EVs), characterized by low immunogenicity, high biocompatibility and targeting specificity along with excellent blood-brain barrier permeability,... (Review)
Review
Extracellular vesicles (EVs), characterized by low immunogenicity, high biocompatibility and targeting specificity along with excellent blood-brain barrier permeability, are increasingly recognized as promising drug delivery vehicles for treating a variety of diseases, such as cancer, inflammation and viral infection. However, recent findings demonstrate that the intracellular delivery efficiency of EVs fall short of expectations due to phagocytic clearance mediated by the host mononuclear phagocyte system through Fcγ receptors, complement receptors as well as non-opsonic phagocytic receptors. In this text, we investigate a range of bacterial virulence proteins that antagonize host phagocytic machinery, aiming to explore their potential in engineering EVs to counteract phagocytosis. Special emphasis is placed on IdeS secreted by and ImpA secreted by , as they not only counteract phagocytosis but also bind to highly upregulated surface biomarkers αβ on cancer cells or cleave the tumor growth and metastasis-promoting factor CD44, respectively. This suggests that bacterial anti-phagocytic proteins, after decorated onto EVs using pre-loading or post-loading strategies, can not only improve EV-based drug delivery efficiency by evading host phagocytosis and thus achieve better therapeutic outcomes but also further enable an innovative synergistic EV-based cancer therapy approach by integrating both phagocytosis antagonism and cancer targeting or deactivation.
Topics: Extracellular Vesicles; Phagocytosis; Humans; Animals; Bacterial Proteins; Neoplasms; Integrin alphaVbeta3; Hyaluronan Receptors; Pseudomonas aeruginosa
PubMed: 38903499
DOI: 10.3389/fimmu.2024.1418061 -
Ugeskrift For Laeger Jun 2024Pseudomonas aeruginosa, a Gram-negative bacterium known to induce severe infections, is seldomly reported in scientific literature as a contributor of osteomyelitis. In...
Pseudomonas aeruginosa, a Gram-negative bacterium known to induce severe infections, is seldomly reported in scientific literature as a contributor of osteomyelitis. In this case report, a 71-year-old woman exhibited recurring infections and enduring forearm pain. A subsequent MRI revealed osteomyelitis in the distal ulna, linked to an arterial blood gas sample taken months earlier. Despite undergoing multiple extended courses of antibiotic treatment, the patient eventually underwent surgery on her left forearm. Biopsy cultures conclusively confirmed the presence of P. aeruginosa.
Topics: Humans; Female; Aged; Pseudomonas aeruginosa; Pseudomonas Infections; Osteomyelitis; Ulna; Anti-Bacterial Agents; Magnetic Resonance Imaging; Punctures
PubMed: 38903032
DOI: 10.61409/V01240062 -
Scientific Reports Jun 2024A polyphasic approach was applied to characterize taxonomically a novel endophytic bacterial strain, designated as EP178, which was previously isolated from Passiflora...
A polyphasic approach was applied to characterize taxonomically a novel endophytic bacterial strain, designated as EP178, which was previously isolated from Passiflora incarnata leaves and characterized as plant-growth promoter. The strain EP178 forms Gram stain-negative and rod-shaped cells, and circular and yellow-pigmented colonies. Its growth occurs at 10-37 °C, at pH 6.0-8.0, and tolerates up to 7% (w/v) NaCl. The major cellular fatty acids found were summed feature 8 (C ω7c), summed feature 3 (C ω6c /C ω7c), and C, and the predominant ubiquinone was Q-9. The phylogenetic and nucleotide-similarity analysis with 16S rRNA gene sequences showed that strain EP178 belongs to Pseudomonas genus. The genomic-based G + C content was 65.5%. The average nucleotide identity and digital DNA-DNA hybridization values between strains EP178 and the closest type strain, P. oryzihabitans DSM 6835, were 92.6% and 52.2%, respectively. Various genes associated with plant-growth promoting mechanisms were annotated from genome sequences. Based on the phenotypic, genomic, phylogeny and chemotaxonomic data, strain EP178 represents a new species of the genus Pseudomonas, for which the name Pseudomonas flavocrustae sp. nov. was proposed. The type strain is EP178 (= CBMAI 2609 = ICMP 24844 = MUM 23.01).
Topics: Endophytes; Phylogeny; Pseudomonas; Passiflora; RNA, Ribosomal, 16S; Base Composition; Fatty Acids; DNA, Bacterial; Plant Leaves; Nucleic Acid Hybridization
PubMed: 38902258
DOI: 10.1038/s41598-024-64349-1 -
Microbiology (Reading, England) Jun 2024Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary infection, despite how limited the clinically achievable...
Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary infection, despite how limited the clinically achievable concentrations are, being far below their MICs. An increase in the sub-MIC of macrolide exposure-dependent sensitivity to nitrosative stress is a typical characteristic of . However, a few clinical isolates do not respond to sub-MIC of macrolide treatment. Therefore, we examined the effects of sub-MIC of erythromycin (EM) on the sensitivity to nitrosative stress together with an efflux pump inhibitor (EPI) phenylalanine arginyl β-naphthylamide (PAβN). The sensitivity to nitrosative stress increased, suggesting that the efflux pump was involved in inhibiting the sub-MIC of macrolide effect. Analysis using efflux pump-mutant revealed that MexAB-OprM, MexXY-OprM, and MexCD-OprJ are factors in reducing the sub-MIC of macrolide effect. Since macrolides interfere with quorum sensing (QS), we demonstrated that the QS-interfering agent furanone C-30 (C-30) producing greater sensitivity to nitric oxide (NO) stress than EM. The effect of C-30 was decreased by overproduction of MexAB-OprM. To investigate whether the increase in the QS-interfering agent exposure-dependent sensitivity to nitrosative stress is characteristic of clinical isolates, we examined the viability of treated with NO. Although treatment with EM could reduce cell viability, a high variability in EM effects was observed. Conversely, C-30 was highly effective at reducing cell viability. Treatment with both C-30 and PAβN was sufficiently effective against the remaining isolates. Therefore, the combination of a QS-interfering agent and an EPI could be effective in treating infections.
Topics: Pseudomonas aeruginosa; Quorum Sensing; Microbial Sensitivity Tests; Anti-Bacterial Agents; Nitrosative Stress; Erythromycin; Membrane Transport Proteins; Furans; Dipeptides; Macrolides; Pseudomonas Infections; Humans; Bacterial Outer Membrane Proteins; Bacterial Proteins
PubMed: 38900549
DOI: 10.1099/mic.0.001464 -
Virulence Dec 2024is one of the leading causes of nosocomial infections worldwide and has emerged as a serious public health threat, due in large part to its multiple virulence factors...
is one of the leading causes of nosocomial infections worldwide and has emerged as a serious public health threat, due in large part to its multiple virulence factors and remarkable resistance capabilities. Stk1, a eukaryotic-type Ser/Thr protein kinase, has been shown in our previous work to be involved in the regulation of several signalling pathways and biological processes. Here, we demonstrate that deletion of leads to alterations in several virulence- and resistance-related physiological functions, including reduced pyocyanin and pyoverdine production, attenuated twitching motility, and enhanced biofilm production, extracellular polysaccharide secretion, and antibiotic resistance. Moreover, we identified AlgR, an important transcriptional regulator, as a substrate for Stk1, with its phosphorylation at the Ser143 site catalysed by Stk1. Intriguingly, both the deletion of and the mutation of Ser143 of AlgR to Ala result in similar changes in the above-mentioned physiological functions. Furthermore, assays of expression in these strains suggest that changes in the phosphorylation state of AlgR, rather than its expression level, underlie changes in these physiological functions. These findings uncover Stk1-mediated phosphorylation of AlgR as an important mechanism for regulating virulence and resistance in .
Topics: Pseudomonas aeruginosa; Phosphorylation; Bacterial Proteins; Virulence; Protein Serine-Threonine Kinases; Gene Expression Regulation, Bacterial; Virulence Factors; Biofilms; Transcription Factors; Drug Resistance, Bacterial; Pseudomonas Infections; Trans-Activators
PubMed: 38898809
DOI: 10.1080/21505594.2024.2367649 -
BMC Research Notes Jun 2024The purpose of this study was to evaluate antibacterial activity of pigment extracted from bacteria, isolated from soil samples. During the study, 20 soil samples were...
The purpose of this study was to evaluate antibacterial activity of pigment extracted from bacteria, isolated from soil samples. During the study, 20 soil samples were collected from different areas (forest, agriculture fields, river sides and dumping sites) of Kathmandu and Lalitpur districts which were processed for isolation of pigment producing bacteria by spread plate technique. The pigmented bacterial isolates were identified and enriched in nutrient broth. Then, pigment was extracted in 95% methanol as solvent, which was further characterized using UV-Vis Spectrophotometric and TLC analysis. The obtained crude pigment extract was processed to carry out the antimicrobial susceptibility assay using agar well diffusion method. Out of 13 total pigmented bacteria isolates, four different colored pigmented bacterial isolates (S4O, S11Y, S14P and S17G) which produced efficient pigment on nutrient agar were chosen and they were further processed. Among these isolates, S4O was identified as Staphylococcus aureus, S11Y was identified as Micrococcus luteus, S14P was identified as Micrococcus roseus and S17G was identified as Pseudomonas aeruginosa respectively. On characterization using UV-Vis Spectrophotometric and TLC analysis, the pigment extracted from isolates S4O, S11Y and S14P were found to be Carotenoids and from isolate S17G was found to be Pyocyanin in nature. The maximum antibacterial activity was shown against Staphylococcus aureus from all the four pigments extracts. The green color pigment extract from isolate S17G was found to be most effective against all the Gram-positive and Gram-negative test bacteria. This study suggests that these pigment extracts from pigmented bacteria may have beneficial antibacterial roles that can be exploited in controlling unwanted bacterial growth.
Topics: Anti-Bacterial Agents; Soil Microbiology; Pigments, Biological; Microbial Sensitivity Tests; Staphylococcus aureus; Pseudomonas aeruginosa; Bacteria; Micrococcus luteus
PubMed: 38898523
DOI: 10.1186/s13104-024-06834-4 -
Veterinary Medicine and Science Jul 2024Bersama abyssinica Fresen is a plant that is used in folk medicine for the treatment of mastitis and other infectious diseases.
BACKGROUND
Bersama abyssinica Fresen is a plant that is used in folk medicine for the treatment of mastitis and other infectious diseases.
OBIECTIVE
The antibacterial activity of methanol crude extract of plant was evaluated against three common bacterial pathogens, including Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli and Pseudomonas aeruginosa).
METHODS
The antibacterial activities and minimum inhibitory concentration of B. abyssinica crude extracts were evaluated using agar-well diffusion and broth dilution methods according to the National Committee for Clinical Laboratory Standards (NCCLS).
RESULTS
A significant difference in the antibacterial activity of crude extracts was observed among different levels of concentration against tested isolates. A higher mean inhibition zone diameter was recorded in E. coli (29.2 ± 1.5 mm), followed by S. aureus (27.8 ± 1.1 mm) and P. aeruginosa (18.0 ± 0.7 mm) at a concentration of 100 mg/mL. The antibacterial activity of crude plant extract at 100 mg/mL was comparable with that of a standard antibiotic (27.6 ± 2.6) against S. aureus and E. coli isolates. The findings indicated that bacterial growth inhibition increased as the concentration of the crude extracts increased. E. coli and S. aureus isolates showed significantly higher susceptibilities to crude extracts than P. aeruginosa at all concentrations. The minimum inhibitory concentrations of extracts against S. aureus, E. coli and P. aeruginosa isolates were 0.78 mg/mL, 1.56 mg/mL and 1.56 mg/mL, respectively.
CONCLUSIONS
All tested pathogenic bacterial species were susceptible to plant leaf extract and broad-spectrum activity against Gram-positive and Gram-negative bacteria. The study recommends further fractionation of the B. abyssinica plant that contributes to its antibacterial activity and understands the mode of action of this plant against bacteria and other microbes.
Topics: Plant Extracts; Anti-Bacterial Agents; Microbial Sensitivity Tests; Gram-Negative Bacteria; Gram-Positive Bacteria; Escherichia coli; Staphylococcus aureus; Pseudomonas aeruginosa
PubMed: 38896065
DOI: 10.1002/vms3.1498 -
Molecules (Basel, Switzerland) May 2024Novel isoxazole-triazole conjugates have been efficiently synthesized using 3-formylchromone as starting material according to a multi-step synthetic approach. The...
Novel isoxazole-triazole conjugates have been efficiently synthesized using 3-formylchromone as starting material according to a multi-step synthetic approach. The structures of the target conjugates and intermediate products were characterized by standard spectroscopic techniques (H NMR and C NMR) and confirmed by mass spectrometry (MS). The all-synthesized compounds were screened for their antibacterial activity against three ATCC reference strains, namely ATCC 25923, ATCC BAA-44, and ATCC 25922 as well as one strain isolated from the hospital environment . The findings indicate that conjugate 7b exhibits a stronger antibacterial response against the tested ATCC 25922 and pathogenic strains compared to the standard antibiotics. Furthermore, hybrid compound proved to have a bactericidal action on the ATCC 25922 strain, as evidenced by the results of the MBC determination. Moreover, the ADMET pharmacokinetic characteristics revealed a favorable profile for the examined compound, as well as a good level of oral bioavailability. Molecular docking and molecular dynamics simulations were performed to explore the inhibition mechanism and binding energies of conjugate with the proteins of and bacterial strains. The in silico results corroborated the data observed in the in vitro evaluation for compound .
Topics: Anti-Bacterial Agents; Triazoles; Molecular Docking Simulation; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Escherichia coli; Isoxazoles; Staphylococcus aureus; Drug Design; Molecular Dynamics Simulation; Molecular Structure; Structure-Activity Relationship; Computer Simulation
PubMed: 38893386
DOI: 10.3390/molecules29112510 -
Molecules (Basel, Switzerland) May 2024The human paraoxonase 2 (PON2) is the oldest member of a small family of arylesterase and lactonase enzymes, representing the first line of defense against bacterial...
The human paraoxonase 2 (PON2) is the oldest member of a small family of arylesterase and lactonase enzymes, representing the first line of defense against bacterial infections and having a major role in ROS-associated diseases such as cancer, cardiovascular diseases, neurodegeneration, and diabetes. Specific Post-Translational Modifications (PTMs) clustering nearby two residues corresponding to polymorphic sites and their impact on the catalytic activity are not yet fully understood. Thus, the goal of the present study was to develop an improved PON2 purification protocol to obtain a higher amount of protein suitable for in-depth biochemical studies and biotechnological applications. To this end, we also tested several compounds to stabilize the active monomeric form of the enzyme. Storing the enzyme at 4 °C with 30 mM Threalose had the best impact on the activity, which was preserved for at least 30 days. The catalytic parameters against the substrate 3-Oxo-dodecanoyl-Homoserine Lactone (3oxoC12-HSL) and the enzyme ability to interfere with the biofilm formation of () were determined, showing that the obtained enzyme is well suited for downstream applications. Finally, we used the purified rPON2 to detect, by the direct molecular fishing (DMF) method, new putative PON2 interactors from soluble extracts of HeLa cells.
Topics: Aryldialkylphosphatase; Humans; Proteomics; Protein Refolding; Pseudomonas aeruginosa; Enzyme Stability; Biofilms; Protein Processing, Post-Translational
PubMed: 38893310
DOI: 10.3390/molecules29112434