represses type VI secretion system through a manganese-dependent small RNA-mediated regulation.

Type VI secretion system (T6SS) is utilized by many Gram-negative bacteria to eliminate competing bacterial species and manipulate host cells. ATCC 17978 utilizes T6SS at the expense of losing pAB3 plasmid to induce contact-dependent killing of competitor microbes, resulting in the loss of antibiotic resistance carried by pAB3. However, the regulatory network associated with T6SS in remains poorly understood.

Overexpression of l,d-Transpeptidase A Induces Dispensability of Rod Complex in .

Antimicrobial resistance (AMR) is a significant global threat, and the presence of resistance-determinant genes is one of the major driving forces behind it. The bacterial rod complex is an essential set of proteins that is crucial for cell survival due to its role in cell wall biogenesis and shape maintenance. Therefore, these proteins offer excellent potential as drug targets; however, compensatory mutations in nontarget genes render this complex nonessential.

A screen for cell envelope stress uncovers an inhibitor of prolipoprotein diacylglyceryl transferase, Lgt, in .

The increasing prevalence of antibiotic resistance demands the discovery of antibacterial chemical scaffolds with unique mechanisms of action. Phenotypic screening approaches, such as the use of reporters for bacterial cell stress, offer promise to identify compounds while providing strong hypotheses for follow-on mechanism of action studies. From a collection of ∼1,800 GFP transcriptional reporter strains, we identified a reporter that is highly induced by cell envelope stress-pProm -GFP.

CARD 2023: expanded curation, support for machine learning, and resistome prediction at the Comprehensive Antibiotic Resistance Database.

The Comprehensive Antibiotic Resistance Database (CARD; card.mcmaster.ca) combines the Antibiotic Resistance Ontology (ARO) with curated AMR gene (ARG) sequences and resistance-conferring mutations to provide an informatics framework for annotation and interpretation of resistomes.

Genetic and Chemical Screening Reveals Targets and Compounds to Potentiate Gram-Positive Antibiotics against Gram-Negative Bacteria.

Gram-negative bacteria are intrinsically resistant to a plethora of antibiotics that effectively inhibit the growth of Gram-positive bacteria. The intrinsic resistance of Gram-negative bacteria to classes of antibiotics, including rifamycins, aminocoumarins, macrolides, glycopeptides, and oxazolidinones, has largely been attributed to their lack of accumulation within cells due to poor permeability across the outer membrane, susceptibility to efflux pumps, or a combination of these factors. Due to the difficulty in discovering antibiotics that can bypass these barriers, finding targets and compounds that increase the activity of these ineffective antibiotics against Gram-negative bacteria has the potential to expand the antibiotic spectrum.

Antibacterial Activity of Metergoline Analogues: Revisiting the Ergot Alkaloid Scaffold for Antibiotic Discovery.

Metergoline is a semisynthetic ergot alkaloid identified recently as an inhibitor of the Gram-negative intracellular pathogen Typhimurium ( Tm). With the previously unknown antibacterial activity of metergoline, we explored structure-activity relationships (SARs) with a series of carbamate, urea, sulfonamide, amine, and amide analogues. Cinnamide and arylacrylamide derivatives show improved potency relative to metergoline against Gram-positive bacteria, and pyridine derivative is also effective against methicillin-resistant (MRSA) in a murine skin infection model.

Integration of VEK-30 peptide enhances fibrinolytic properties of staphylokinase.

Staphylokinase (SAK), a 136 amino acid bacterial protein with profibrinolytic properties, has emerged as an important thrombolytic agent because of its fibrin specificity and reduced inhibition by α-2 antiplasmin. In an attempt to enhance the clot dissolution ability of SAK, a 30 amino acid peptide (VEK-30) derived from a plasminogen (Pg) binding protein (PAM), was fused at the C-terminal end of SAK with a RGD (Arg-Gly-Asp) linker. The chimeric protein, SAKVEK, was expressed in E.

Antibacterial properties and in vivo efficacy of a novel nitrofuran, IITR06144, against MDR pathogens.

Objectives: The emergence of MDR Gram-negative pathogens and increasing prevalence of chronic infections presents an unmet need for the discovery of novel antibacterial agents. The aim of this study was to evaluate the biological properties of a small molecule, IITR06144, identified in a phenotypic screen against the Gram-negative model organism Escherichia coli.

Methods: A small-molecule library of 10956 compounds was screened for growth inhibition against E.

The unusual glycine-rich C terminus of the RNA chaperone Hfq plays an important role in bacterial physiology.

is a Gram-negative nosocomial pathogen that causes soft tissue infections in patients who spend a long time in intensive care units. This recalcitrant bacterium is very well known for developing rapid drug resistance, which is a combined outcome of its natural competence and mobile genetic elements. Successful efforts to treat these infections would be aided by additional information on the physiology of Toward that end, we recently reported on a small RNA (sRNA), AbsR25, in this bacterium that regulates the genes of several efflux pumps.

Fosfomycin resistance in Acinetobacter baumannii is mediated by efflux through a major facilitator superfamily (MFS) transporter-AbaF.

Objectives: To decipher the function of A1S_1331, named AbaF (Acinetobacter baumannii Fosfomycin efflux), one of the primary targets of AbsR25, a small RNA of A. baumannii.

Methods: abaF was cloned in a multicopy plasmid and expressed from its native promoter in an efflux-deficient strain-Escherichia coli KAM32.

Bilobed shape of PadA reveals the connectivity from single to multi-domain bacterial plasminogen activators.

The bacterial plasminogen activator, PadA activates bovine, ovine and caprine plasminogen but remains inert toward human plasminogen. It shows high sequence homology with human plasminogen activator, staphylokinase (SAK) but generates active-site in bovine plasminogen non-proteolytically, similar to streptokinase (SK). To examine the structural requirements for the function of this unique cofactor, attempts were made to visualize solution structure of the PadA using small-angle X-ray scattering (SAXS) data and compare its shape profile with structural models based on crystal structures of staphylokinase and streptokinase domains.

Fibrin-targeted plasminogen activation by plasminogen activator, PadA, from Streptococcus dysgalactiae.

Bacterial plasminogen activators differ from each other in their mechanism of plasminogen activation besides their host specificity. Three-domain streptokinase (SK) and two-domain PauA generate nonproteolytic active site center in their cognate partner plasminogen but their binary activator complexes are resistant to α2-antiplasmin (a2AP) inhibition causing nonspecific plasminogen activation in plasma. In contrast, single-domain plasminogen activator, staphylokinase (SAK), requires proteolytic cleavage of human plasminogen into plasmin for the active site generation, and this activator complex is inhibited by a2AP.