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Increasing Drug Resistance in Salmonella enterica Serovar Typhimurium: Implications for Treatment

Salmonella enterica Serovar Typhimurium is a significant cause of food-borne gastroenteritis, presenting with symptoms like diarrhea, abdominal cramps, and fever. The rising risk of drug resistance, particularly to quinolones, poses a serious challenge in treatment, as it can lead to life-threatening enteric fevers. Efflux pump overexpression and mutations in topoisomerase are key mechanisms in this resistance. Recent studies have highlighted the emergence of quinolone-resistant mutants and the limitations of current antibiotic therapies, underscoring the need for new strategies in combating salmonellosis.

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Increasing Drug Resistance in Salmonella enterica Serovar Typhimurium: Implications for Treatment

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  1. Speaker:黃思偉

  2. http://www.technologijos.lt Salmonella enterica Serovar Typhimurium caused food-borne gastroenteritis has an increasing risk of drug resistance Salmonella gastroenteritis (diarrhea, abdominal cramps, and fever) to enteric fevers (including typhoid fever) which are life-threatening febrile systemic illness requiring prompt antibiotic therapy. Focal infections and an asymptomatic carrier state occur. The most common form of salmonellosis is a self-limited, uncomplicated gastroenteritis

  3. quinolones Amino acid substitutions of Gyrase A lead to quinolone resistance Quinolones can kill bacteria by inhibiting DNA replication

  4. Biochem. J.376: 313-8 (2003)

  5. AcrAB-tolC system overexpression is mediated by transcription factors MARA, and SoxS

  6. 1. Salmonella enterica Serovar Typhimurium strain S21 isolated from ground beef sample underwent in vitro quinolone-selection to generate quinolone-resistance mutant strains: S21-1, S21-2, S21-3, and S21-4. 2. Clinical isolates with ciprofloxacin resistance from pig feces: CS1, CS3, and CS9. 3. Clinical isolates with nalidixic acid resistance from retail chicken meat: CHS14, CHS18, and CHS38. Detect if there is quinolone-resistance genetic alterations by PCR methods Knock out efflux pump genes or replace the mutant topoisomerase and gyrase gene with the wild type Minimum inhibition concentration (MIC) of quinolones or other anti-bacteria drugs

  7. In comparison with the parental S21 strain, the quinolone-resistant mutants expressed more efflux pump.

  8. Both efflux pump and topoisomerase mutations are important for quinolone-resistance, and sometimes efflux pump plays an more important role, especially in clinical isolates.

  9. Konckout of efflux pump genes and replacement of gyrase gene with the wild type were incapable of affecting the susceptibility of chloramphenicol, tetracycline, and b-lactams.

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