Publications by authors named "Katherine Lev"

Specialized or secondary metabolites are small molecules of biological origin, often showing potent biological activities with applications in agriculture, engineering and medicine. Usually, the biosynthesis of these natural products is governed by sets of co-regulated and physically clustered genes known as biosynthetic gene clusters (BGCs). To share information about BGCs in a standardized and machine-readable way, the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard and repository was initiated in 2015.

View Article and Find Full Text PDF
Article Synopsis
  • - M2D2 is a two-stage machine learning pipeline that helps discover effective antimicrobial drug combinations, aiming to tackle drug resistance without the need for costly omics data.
  • - It enhances the accuracy of identifying drug targets by using both experimental and computational methods, and provides insights into how different drugs interact with each other.
  • - The framework was validated with experiments involving 946 combinations of approved drugs and antibiotics, revealing promising synergies, including a notable combination of a cerebrovascular drug and penicillin, while also confirming these findings through genome-wide CRISPR screens.
View Article and Find Full Text PDF

Plecomacrolides, such as concanamycins and bafilomycins, are potent and specific inhibitors of vacuolar-type ATPase. Concanamycins are 18-membered macrolides with promising therapeutic potential against multiple diseases, including viral infection, osteoporosis, and cancer. Due to the complexity of their total synthesis, the production of concanamycins is only achieved through microbial fermentation.

View Article and Find Full Text PDF

Biofilm-producing infections pose a severe threat to public health and are responsible for high morbidity and mortality. Phage-antibiotic combinations (PACs) are a promising strategy for combatting multidrug-resistant (MDR), extensively drug-resistant (XDR), and difficult-to-treat infections. Ten MDR/XDR strains and five .

View Article and Find Full Text PDF

Introduction: Daptomycin (DAP) has proven to be a viable alternative amid vancomycin resistance; however, the use of DAP post vancomycin treatment has led to the development of DAP non-susceptible (DNS) strains. Dalbavancin (DAL), a novel single-dosed lipoglycopeptide, has shown enhanced activity against highly resistant Staphylococcus aureus strains. However, on the basis of previous reports and our observations, DAL does not demonstrate similar activity at high versus low inoculum levels.

View Article and Find Full Text PDF

Biofilm-associated infections lead to substantial morbidity. Omadacycline (OMC) is a novel aminomethylcycline with potent activity against Staphylococcus aureus and Staphylococcus epidermidis, but data surrounding its use in biofilm-associated infections are lacking. We investigated the activity of OMC alone and in combination with rifampin (RIF) against 20 clinical strains of staphylococci in multiple biofilm analyses, including an pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor (CBR) model (simulating human exposures).

View Article and Find Full Text PDF

Aims: Here, we investigate the impact of phage-antibiotic combinations (PAC) on bacterial killing, resistance development and outer membrane vesicle (OMV) production in multidrug-resistant (MDR) P. aeruginosa.

Methods And Results: After screening 10 well-characterized MDR P.

View Article and Find Full Text PDF

Bacterial biofilms are difficult to eradicate and can complicate many infections by forming on tissues and medical devices. Phage+antibiotic combinations (PAC) may be more active on biofilms than either type of agent alone, but it is difficult to predict which PAC regimens will be reliably effective. To establish a method for screening PAC combinations against Staphylococcus aureus biofilms, we conducted biofilm time-kill analyses (TKA) using various combinations of phage Sb-1 with clinically relevant antibiotics.

View Article and Find Full Text PDF
Article Synopsis
  • Multidrug-resistant Enterococcus faecium is a tough bacteria that causes infections and is hard to treat due to limited effective drugs.
  • Researchers tested two strains of this bacteria to see how well they could be treated using bacteriophages that specifically target and kill bacteria, combined with antibiotics like daptomycin (DAP) and ampicillin (AMP).
  • The study found that using phages with specific antibiotics was more effective at killing the bacteria than using any single treatment alone and also reduced the chances of the bacteria developing resistance.
View Article and Find Full Text PDF

Pseudouridine (Ψ) is a ubiquitous RNA modification incorporated by pseudouridine synthase (Pus) enzymes into hundreds of noncoding and protein-coding RNA substrates. Here, we determined the contributions of substrate structure and protein sequence to binding and catalysis by pseudouridine synthase 7 (Pus7), one of the principal messenger RNA (mRNA) modifying enzymes. Pus7 is distinct among the eukaryotic Pus proteins because it modifies a wider variety of substrates and shares limited homology with other Pus family members.

View Article and Find Full Text PDF

Enterococcus faecium is a significant multidrug-resistant pathogen. Bacteriophage cocktails are being proposed to complement antibiotic therapy. After a screen of 8 E.

View Article and Find Full Text PDF

Exebacase is a lysin (cell wall hydrolase) with direct lytic activity against Staphylococcus aureus including methicillin-resistant S. aureus (MRSA). Time-kill analysis experiments illustrated bactericidal activity of exebacase-daptomycin against MRSA strains MW2 and 494.

View Article and Find Full Text PDF
Article Synopsis
  • This text discusses a dangerous Gram-negative pathogen that is a major cause of healthcare-associated diseases and is resistant to many antibiotics, making treatment challenging.
  • The review focuses on bacteriophages, which are viruses that can target bacteria and offer a potential alternative to antibiotics for treating multidrug-resistant infections.
  • It emphasizes the importance of understanding phage therapy's clinical pharmacology, including pharmacokinetics, formulation, and dosing, to improve treatment outcomes for difficult-to-treat infections.
View Article and Find Full Text PDF

This study aimed to test the efficacy of bacteriophage-antibiotic combinations (BACs) in 24-h time-kill settings and in simulated endocardial vegetation (SEV) pharmacokinetic/pharmacodynamic models for 96 h. BACs prevented the development of bacteriophage resistance, while some bacteriophage resistance emerged in bacteriophage-alone treatments. In addition, BACs resulted in an enhancement of bacterial eradication in SEV models.

View Article and Find Full Text PDF

The most efficacious antimicrobial therapy to aid in the successful elimination of resistant infections is unknown. In this study, we evaluated varying phenotypes of against dalbavancin (DAL), vancomycin (VAN), and daptomycin (DAP) alone and in combination with cefazolin (CFZ). The objective of this study was to observe whether there was a therapeutic improvement in adding a beta-lactam to a glycopeptide, lipopeptide, or a lipoglycopeptide.

View Article and Find Full Text PDF

Concerns regarding increased prevalence of daptomycin (DAP)-resistant strains necessitate novel therapies for infections. Obligately lytic bacteriophages are viruses that target, infect, and kill bacterial cells. Limited studies have evaluated phage-antibiotic combinations against After an initial screen of eight strains, three strains with varying DAP/phage susceptibilities were selected for further experiments.

View Article and Find Full Text PDF

Comparative time-kill experiments with bacteriophage (phage) Sb-1 alone and phage-antibiotic combinations (PACs) against two methicillin-resistant (MRSA) strains have shown synergy with both daptomycin-phage and vancomycin-phage combinations. PACs prevented development of phage resistance and demonstrated bactericidal activity for all triple combinations. In addition, the extracellular membrane vesicle (MV) formation and the potential impact of phage on MV suppression were examined.

View Article and Find Full Text PDF

strains are commonly resistant to vancomycin and β-lactams. In addition, often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant (VREfm), namely, strains S447 and HOU503, in an biofilm model.

View Article and Find Full Text PDF

Multidrug-resistant organisms have caused a marked depletion of effective antimicrobials, and the narrow pipeline of antibiotics has demanded the need to find novel therapeutic alternatives including nonantibiotic agents. Bacteriophages (phages) are viruses that use the bacterial machinery to infect, replicate, and kill bacterial cells. Although a marked decline in their use was driven by the discovery of antibiotics, the era of antibiotic resistance has led to a resurgence of phage therapy into clinical practice.

View Article and Find Full Text PDF

Protein-protein interactions (PPIs) represent important and promising therapeutic targets that are associated with the regulation of various molecular pathways, particularly in cancer. Although they were once considered "undruggable," the recent advances in screening strategies, structure-based design, and elucidating the nature of hot spots on PPI interfaces, have led to the discovery and development of successful small-molecule inhibitors. In this report, we are describing an integrated high-throughput and computational screening approach to enable the discovery of small-molecule PPI inhibitors of the anti-apoptotic protein, Mcl-1.

View Article and Find Full Text PDF