Polymyxins with Potent Antibacterial Activity against Colistin-Resistant Pathogens: Fine-Tuning Hydrophobicity with Unnatural Amino Acids.

In view of the increased prevalence of antimicrobial resistance among human pathogens, antibiotics against multidrug-resistant (MDR) bacteria are in urgent demand. In particular, the rapidly emerging resistance to last-resort antibiotic colistin, used for severe Gram-negative MDR infections, is critical. Here, a series of polymyxins containing unnatural amino acids were explored, and some analogues exhibited excellent antibacterial activity against , , , and .

Antisense Peptide Nucleic Acid-Diaminobutanoic Acid Dendron Conjugates with SbmA-Independent Antimicrobial Activity against Gram-Negative Bacteria.

Precision antisense antibacterial agents may be developed into novel antibiotics in the fight against multidrug-resistant Gram-negative bacteria. In this study, a series of diaminobutanoic acid (DAB) dendrons are presented as novel carriers for the delivery of antisense antibacterial peptide nucleic acids (PNAs). The dendron-PNA conjugates targeting the essential gene exhibit specific antisense antimicrobial bactericidal activity against and at one-digit micromolar concentrations, while showing low toxicity to human cells.

Evaluation of accessible regions of mRNA through computational prediction and experimental investigation.

Background And Objectives: This study aimed to investigate the accessible regions of the mRNA using computational prediction and dot-blot hybridization to increase the effectiveness of antisense anti-virulence therapeutics against Uropathogenic

Materials And Methods: We predicted the secondary structure of the mRNA using the Sfold and Mfold Web servers and RNA structure 5.5 program. Considering the predicted secondary structure, accessible regions in mRNA of were determined and oligonucleotides complementary to these regions were synthesized and hybridization activity of those oligonucleotides to the Digoxigenin (DIG) labeled mRNA was assessed with dot-blot hybridization.

Antibiotic Potentiation in Multidrug-Resistant Gram-Negative Pathogenic Bacteria by a Synthetic Peptidomimetic.

The peptidomimetic H-[NLys-BuAla]-NH (CEP-136), which exhibits low inherent antimicrobial activity against Gram-negative bacteria (MIC = 16-64 μM), was shown to significantly potentiate the antibacterial activity of several clinically important antibiotics against the human pathogens , , , and . Thus, the antibacterial spectrum of rifampicin, clarithromycin, and azithromycin could be extended to include also these Gram-negative bacteria. Additionally, the potentiation effect was demonstrated in a panel of clinically relevant multidrug-resistant isolates including extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing as well as colistin-resistant strains.

Identification and characterization of the type II toxin-antitoxin systems in the carbapenem-resistant Acinetobacterbaumannii.

Carbapenem -resistant A. baumannii (CRAB) is a major cause of both community-associated and nosocomial infections that are difficult to control and treat worldwide. Among different mediators of pathogenesis, toxin-antitoxin (TA) systems are emerging as the most prominent.

The Frequency of Genes in Extended-Spectrum β-lactamases and non-ESBLs Species Isolated from Patients in Mashhad, Iran.

Background And Objectives: Since the fluoroquinolones are the broad-spectrum antibiotics, they affect both Gram-negative and Gram-positive bacteria. These antibiotics are widely prescribed by physicians. As a result, some bacteria, especially Enterobacteriaceae, have shown a resistance to this family of antibiotics The current study aimed at detecting the frequency of , and genes, novel plasmid-mediated quinolone-resistance genes, among extended-spectrum β-lactamases (ESBL)-positive and ESBL-negative isolates.

Prevalence of Quinolone Resistance Genes Among Extended-Spectrum B-Lactamase-Producing Escherichia coli in Mashhad, Iran.

Background: Escherichia coli is an important bacterial species based on incidence and associated infection severity. Some E. coli strains produce extended-spectrum beta lactamase (ESBL) and are called ESBL-producing E.

Variability in gene cassette patterns of class 1 and 2 integrons associated with multi drug resistance patterns in Staphylococcus aureus clinical isolates in Tehran-Iran.

Background: To investigate antibiotic resistance, the occurrence and distribution of class 1 and 2 integrons in multidrug- resistant Staphylococcus aureus isolates from hospitals in Tehran, Iran. The isolates were examined for susceptibility to antimicrobial agents. The mecA gene, class 1 and 2 integrons were detected by PCR.