The isolation of mutants of Staphylococcus aureus that are affected in the stability of penicillinase plasmids is described. One mutation is plasmid borne and results in nonreplication of the plasmid at 42 C. A second type of mutation is host-borne and gives rise to instability of both mcr(I) and mcr(II) penicillinase plasmids but not a tetracycline-resistant plasmid.

Quinolones are a large and widely consumed class of synthetic drugs. Expanded-spectrum quinolones, like ciprofloxacin are highly effective against Gram-negative bacteria, especially Escherichia coli. In E. coli the major target for quinolones is DNA gyrase. This enzyme is composed of two subunits, GyrA and GyrB encoding by gyrA and gyrB, respectively. Mutations in either of these genes cause qu...

root colonization by antagonist bacteria has been considered as a prerequisite for a successful biocontrol. for an effective suppression of plant disease, an efficient and fast colonization is necessary to prevent the establishment of pathogen on the root system. colonization of canola root by strain utpf86 were investigated with and without rhizoctonia solani ag-4, under greenhouse conditions....

The effects of mutations in host genes on tetracycline resistance mediated by the Tet(O) and Tet(M) ribosomal protection proteins, which originated in Campylobacter spp. and Streptococcus spp., respectively, were investigated by using mutants of Salmonella typhimurium and Escherichia coli. The miaA, miaB, and miaAB double mutants of S. typhimurium specify enzymes for tRNA modification at the ad...

The sensitivities of gonococcal isolates to six antibiotics were determined for gonococci isolated in Philadelphia in 1972. The degree of association between susceptibilities to any two antibiotics was determined (coefficient of correlation). The correlation between penicillin and tetracycline (r = 0.75) was almost as good as that between two penicillins, penicillin G and ampicillin (r = 0.85),...

AcrAB-TolC is a major efflux pump in Escherichia coli. It was reported that tolC is overexpressed and involves in improving the organic solvent tolerance level in Escherichia coli marR mutants that are resistant to several antibiotics, such as ciprofloxacin. Low and intermediate levels resistance did not improve organic solvent tolerance. Thus, in this descriptive-experimental study it was deci...

The tetracycline antiporter TetA(B) is a member of the Major Facilitator Superfamily which confers tetracycline resistance to cells by coupling the efflux of tetracycline to the influx of protons down their chemical potential gradient. Although it is a medically important transporter, its structure has yet to be determined. One possibility for why this has proven difficult is that the transport...

Linkevičius, M. 2015. Evolution and Mechanisms of Tigecycline Resistance in Escherichia coli. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 1121. 58 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9285-4. Antibiotic resistance is an ongoing global medical crisis and we are in great need of new antibacterial agents to combat rapidly emerging r...

AcrAB-TolC is a major efflux pump in Escherichia coli. It was reported that tolC is overexpressed and involves in improving the organic solvent tolerance level in Escherichia coli marR mutants that are resistant to several antibiotics, such as ciprofloxacin. Low and intermediate levels resistance did not improve organic solvent tolerance. Thus, in this descriptive-experimental study it was deci...

Appearance of bacteria resistant to antibacterial agents puts physicians in trouble and threatens the health of the world. The rapid development of bacterial resistance in Escherichia coli to ciprofloxacin makes difficult the treatment of infectious diseases. So, detection of the locations of possible mutations in gyrase A gene ( gyrA ) in these mutants is very important to determine the mech...