Ciprofloxacin is one of the most widely used antibiotics for the treatment of several infections caused by Gram-negative bacteria, like E. coli. Changes in gyrA, encoding GyrA subunit of DNA gyrase, cause the resistance to ciprofloxacin. Some ciprofloxacin resistant gyrA mutants acquired constitutive expression of marRAB operon due to the gaining mutations in marR, a repressor of this operon. T...

The term enzibiotic was coined from two words, enzyme and antibiotic and usually refers as the bacteriophage enzymes that attack the cell wall of bacteria with lyses [1]. However, enzybiotic present in bacteria, bacteria infected phages and in body fluids like tears, saliva and animal mucous [2]. Antibiotics had used 80 years with success to eradicate pathogenic bacteria like Escherichia, Klebs...

Efficient production of ethanol for use as a renewable fuel requires organisms with a high level of ethanol tolerance. However, this trait is complex and increased tolerance therefore requires mutations in multiple genes and pathways. Here, we use experimental evolution for a system-level analysis of adaptation of Escherichia coli to high ethanol stress. As adaptation to extreme stress often re...

OBJECTIVES The components of the AcrAB-TolC efflux pump function as a tripartite efflux system conferring resistance to multiple antibiotics and the individual components can also function in conjunction with other efflux pumps. This study aimed to establish whether redundancy exists between the homologous periplasmic adaptor proteins (PAPs) AcrA and AcrE and to measure the impact of this redun...

OBJECTIVES To investigate the potential relationship between quinolone resistance and biofilm production in a collection of Salmonella enterica clinical isolates and in S. enterica serovar Typhimurium serial mutants with increasing resistance to ciprofloxacin. METHODS Nalidixic acid susceptibility and biofilm formation were assessed in a collection of 122 S. enterica clinical isolates. An in ...

AcrB is the inner membrane transporter of the tripartite multidrug efflux pump AcrAB-TolC in E. coli, which poses a major obstacle to the treatment of bacterial infections. X-ray structures have identified two types of substrate-binding pockets in the porter domains of AcrB trimer: the proximal binding pocket (PBP) and the distal binding pocket (DBP), and suggest a functional rotating mechanism...

AcrAB-TolC is the major efflux protein complex in Escherichia coli extruding a vast variety of antimicrobial agents from the cell. The inner membrane component AcrB is a homotrimer, and it has been postulated that the monomers cycle consecutively through three conformational stages designated loose (L), tight (T), and open (O) in a concerted fashion. Binding of drugs has been shown at a peripla...

The antibacterial peptide toxin colicin V uses a dedicated signal sequence-independent system for its secretion in Escherichia coli and requires the products of three genes, cvaA, cvaB, and tolC. As a member of the membrane fusion protein family, CvaA is supposed to form a bridge that connects the inner and outer membranes via interaction with CvaB and TolC, respectively. In this study, we inve...

A AAC(60)-Ib-cr, 185 ACHN-975 clinical studies, 163–164 medicinal chemistry, 166 structure, 162 AcrAB-TolC, 180 AcrD, 236 AdeRS, 257 AFN-1252 mechanism of action, 148, 153 resistance, 153 structure, 149 AIM-1, 74 Amicoumacin A, 222 Amikacin indications, 240 structure, 230 synthesis, 4 Aminoglycosides. See also specific drugs historical perspective, 229–230 indications, 239–241 mechanism of acti...