Novel amylomacins from seaweed-associated Bacillus amyloliquefaciens as prospective antimicrobial leads attenuating resistant bacteria

This study aimed to isolate antibacterial leads from a seaweed-associated bacterium. HeterotrophicBacillus amyloliquefaciens MTCC 12716 associated with the seaweedHypnea valentiae, was isolated and screened for antimicrobial properties against drug-resistant pathogens. The bacterial crude extract was purified and three novel amicoumacin-class of isocoumarin analogues, 11 ′-butyl acetate amicoumacin C (amylomacin A), 4′-hydroxy-11′-methoxyethyl carboxylate amicoumacin C (amylomacin B) and 11′-butyl amicoumacin C (amylomacin C) were isolated to homogeneity. The studied amylomacins possessed potential activities againstPseudomonas aeruginosa, vancomycin-resistantEnterococcus faecalis,Klebsiella pneumoniae, methicillin-resistantStaphylococcus aureus, andShigella flexneri with a range of minimum inhibitory concentration values from 0.78 to 3.12  µg/mL, although standard antibiotics ampicillin and chloramphenicol were active at 6.25–25 µg/mL. Noticeably, the amylomacin compound encompassing 4′-hydroxy-11′-methoxyethyl carboxylate amicoumacin C functionality (amylomacin B), displayed considerably greater antagonistic activities aga inst methicillin-resistantS. aureus, vancomycin-resistantE. faecalis,Vibrio parahaemolyticus,Escherichia coli, andK. pneumoniae (minimum inhibitory concentration 0.78  μg/mL) compared to the positive controls and other amylomacin analogues. Antimicrobial properties of the amylomacins,...
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research

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Bioorg Chem. 2021 Nov 8;118:105470. doi: 10.1016/j.bioorg.2021.105470. Online ahead of print.ABSTRACTMesoporous silica nanoparticles (MNs) emerged as new promising drug-delivery platforms capable to overcome resistance in bacteria. Dual loading of drugs on these nanocarriers, exploiting synergistic interactions between the nanoparticles and the drugs, could be considered as a way to increase the efficacy against resistant bacteria with a positive effect even at very low concentrations. Considering that patients with cancer are highly susceptible to almost any type of bacterial infections, in this work, nanocarriers mesopor...
Source: Bioorganic Chemistry - Category: Chemistry Authors: Source Type: research
Euro Surveill. 2021 Nov;26(46). doi: 10.2807/1560-7917.ES.2021.26.46.2001537.ABSTRACTBackgroundIntensive care units (ICU) constitute a high-risk setting for antimicrobial resistance (AMR).AimWe aimed to describe secular AMR trends including meticillin-resistant Staphylococcus aureus (MRSA), glycopeptide-resistant enterococci (GRE), extended-spectrum cephalosporin-resistant Escherichia coli (ESCR-EC) and Klebsiella pneumoniae (ESCR-KP), carbapenem-resistant Enterobacterales (CRE) and Pseudomonas aeruginosa (CRPA) from Swiss ICU. We assessed time trends of antibiotic consumption and identified factors associated with CRE and...
Source: Euro Surveill - Category: Infectious Diseases Authors: Source Type: research
Only 54 of 166 assessed treatments have policies aiding use by low-income countries, says non-profit groupThe world ’s biggest drugs makers have pressed on in the fight against superbugs despite the pandemic, but millions of people in poorer countries, where the risk of drug-resistant infections is highest, are still missing out on key antibiotics.A report from the Access to Medicine Foundation, an Amsterdam-based non-profit group, shows that only 54 of 166 medicines and vaccines assessed are covered by an access strategy to make them available to low- and middle-income countries.Continue reading...
Source: Guardian Unlimited Science - Category: Science Authors: Tags: Pharmaceuticals industry Vaccines and immunisation Tuberculosis E coli Gonorrhoea World Health Organization Business Drug resistance Drugs Drugs policy Medical research Global development Science Netherlands World news Source Type: news
BackgroundIntensive care units (ICU) constitute a high-risk setting for antimicrobial resistance (AMR).AimWe aimed to describe secular AMR trends including meticillin-resistantStaphylococcus aureus (MRSA), glycopeptide-resistantenterococci (GRE), extended-spectrum cephalosporin-resistantEscherichia coli (ESCR-EC) andKlebsiella pneumoniae (ESCR-KP), carbapenem-resistantEnterobacterales (CRE) andPseudomonas aeruginosa (CRPA) from Swiss ICU. We assessed time trends of antibiotic consumption and identified factors associated with CRE and CRPA.MethodsWe analysed patient isolate and antibiotic consumption data of Swiss ICU sent ...
Source: Eurosurveillance - Category: Infectious Diseases Authors: Source Type: research
Conclusion: We report a hospital outbreak caused by the clonal dissemination of KPC-producing ST15 K. pneumoniae but also the intra- and inter-species transmission of the blaKPC–2 gene associated with plasmid conjugation and/or transposon dissemination. To our knowledge, this is the first report of an outbreak caused by KPC-producing Enterobacterales isolated from human patients in Catalonia and highlights the relevance of surveillance studies in the early detection and control of antibiotic resistant high-risk clones.
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
In this study, we successfully developed a design methodology to create synthetic AMPs with a narrow spectrum of activity where the PHNX AMPs demonstrated higher antibacterial activity against Gram-negative bacteria compared to Gram-positive bacteria. Thus, these peptides present novel synthetic peptides with a potential for therapeutic use. Based on our findings, we propose upfront selection of the peptide dataset for analysis, an additional step of positional analysis to add to the ab initio database filtering technology (DFT) method, and we present laboratory data on the novel, synthetically designed AMPs to validate th...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Antimicrob Agents Chemother. 2021 Nov 15:AAC0214621. doi: 10.1128/AAC.02146-21. Online ahead of print.ABSTRACTEscherichia coli ST131 is a recently emerged antibiotic resistant clone responsible for high rates of urinary tract and bloodstream infections. Despite its global dominance, the precise mechanisms that have driven the rapid dissemination of ST131 remain unknown. Here, we show that the plasmid-associated resistance gene encoding the AAC(6')-Ib-cr enzyme that inactivates the fluoroquinolone antibiotic ciprofloxacin is present in>70% of strains from the most rapidly expanding subgroup of multidrug resistant ST131. ...
Source: Antimicrobial Agents and Chemotherapy - Category: Microbiology Authors: Source Type: research
Eur J Med Chem. 2021 Nov 8:113977. doi: 10.1016/j.ejmech.2021.113977. Online ahead of print.ABSTRACTThe increasingly growing epidemics of multidrug-resistant bacteria are becoming severe public health threat. There is in an urgent need to develop new antibacterial agents with broad-spectrum antibacterial activity and high selectivity. Here, a series of N-terminal dipeptide mimetics with an aromatic amide moiety were synthesized from amino acids. The effects of amino acid type and aromatic moiety on the biological activities of the mimetics were evaluated. The dipeptide mimetics not only showed significant broad-spectrum an...
Source: European Journal of Medicinal Chemistry - Category: Chemistry Authors: Source Type: research
Biosens Bioelectron. 2021 Nov 2;197:113754. doi: 10.1016/j.bios.2021.113754. Online ahead of print.ABSTRACTConventional methods for testing antibiotic susceptibility rely on bacterial growth on agar plates (diffusion assays) or in liquid culture (microdilution assays). These time-consuming assays use population growth as a proxy for cellular respiration. Herein we propose to use mediated extracellular electron transfer as a rapid and direct method to classify antibiotic-susceptible and -resistant bacteria. We tested antibiotics with diverse mechanisms of action (ciprofloxacin, imipenem, oxacillin, or tobramycin) with four ...
Source: Biosensors and Bioelectronics - Category: Biotechnology Authors: Source Type: research
Eur J Med Chem. 2021 Nov 8:113977. doi: 10.1016/j.ejmech.2021.113977. Online ahead of print.ABSTRACTThe increasingly growing epidemics of multidrug-resistant bacteria are becoming severe public health threat. There is in an urgent need to develop new antibacterial agents with broad-spectrum antibacterial activity and high selectivity. Here, a series of N-terminal dipeptide mimetics with an aromatic amide moiety were synthesized from amino acids. The effects of amino acid type and aromatic moiety on the biological activities of the mimetics were evaluated. The dipeptide mimetics not only showed significant broad-spectrum an...
Source: European Journal of Medicinal Chemistry - Category: Chemistry Authors: Source Type: research
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