Mechanisms of Resistance to Quinolones and Epidemiological Significance of Salmonella spp.

Abstract

Bacteria develop resistance to antimicrobial agents by a number of different mechanisms. The resistance to (fl uoro)quinolones in Salmonella is of particular importance especially if therapy in humans is required. For decades there has been a signifi cant interest in studying the biology of Salmonella because these bacteria are among the leading causes of foodborne illnesses around the globe. To this date, two main mechanisms of quinolone resistance have been established: alteration in the targets for quinolones, decreased accumulation inside bacteria due to impermeability of the membrane and/or an over expression of the effl ux pump systems. Both of these mechanisms are chromosomally mediated. Furthermore, mobile elements have been described carrying the qnr gene which confers resistance to quinolones. The plasmid encoded QNR proteins belong to the pentapeptide repeat family of proteins. The plasmid mediated quinolone resistance (PMQR) is often associated with the resistance to beta lactam antibiotics. It was noticed that PMQR is backing up chromosomal mutations for quinolone resistance, hence becoming an important resistance mechanism worldwide. Even with our knowledge expanding over the years, it is not possible to predict how bacteria will respond in the future, if they are exposed to new external challenges. The possibility that they will fi nd a way to survive by introducing new mutations or by exchanging mobile genetic elements and subsequently developing resistance to survive in the environment should not be underestimated.

Salmonella Species On Meat Contact Surfaces and Processing Water in Sokoto Main Market and Abattoir, Nigeria

“…This study revealed that Salmonella Typhi was the most frequent isolate. However, in the recent epidemiological studies was indicated that S. Enteritidis and S. Infantis are most frequently isolated from poultry flocks in southern Bačka and Srem region in Serbia (1). Salmonella Typhi is a human pathogen, having high levels of it could be an indication of fecal contamination of these surfaces and processing water.…”

“…There has been a significant interest in studying the biology of Salmonella because these bacteria are among the leading causes of foodborne illnesses around the globe (1). Over 2500 known serotypes, of Salmonella have been isolated so far.…”

Phenotypic characterization of some foodpoisoning bacteria isolated from meat and meat products in Kaliobia, Egypt

“…Salmonella is a food-borne pathogen contaminating food and water. It causes severe acute gastroenteritis and typhoid fever (Vehlner, 2016). Antimicrobial resistance (AMR) is a major global issue for human and animals due to improper use of antibiotics in food animals (Saud et al, 2019;Messele et al, 2017).…”

Bacterial Pathogens in the Food Industry: Antibiotic Resistance and Virulence Factors of Salmonella enterica Strains Isolated from Food Chain Links

“…β-lactam antibiotics block the activity of the enzymes, including transpeptidases and carboxypeptidases, which are involved in the synthesis of peptidoglycan in the bacterial cell wall [68,70,71]. Fluoroquinolones (fluorinated quinolones, FQ) are commonly used in salmonellosis therapy [72,73], and their activity is associated with the inhibition of DNA synthesis by blocking topoisomerases II, DNA gyrase, and topoisomerase IV [74][75][76]. Another group of antibiotics used in the treatment of salmonellosis is aminoglycosides that bind to the 30S ribosome subunit, which leads to a disturbance in the reading of genetic information and inhibition of bacterial protein synthesis [77,78].…”