Multidrug-resistant Salmonella typhi: a worldwide epidemic

Area of Science:

• * Infectious Diseases
• * Microbiology
• * Antimicrobial Resistance

Background:

• * Multidrug-resistant (MDR) Salmonella typhi strains, resistant to chloramphenicol, ampicillin, and trimethoprim, have caused widespread outbreaks since 1989.
• * These MDR strains are prevalent in the Indian subcontinent, Southeast Asia, Africa, the Arabian Gulf, and are increasingly found in travelers returning to developed countries.
• * Resistance in MDR strains is typically plasmid-encoded, specifically by plasmids of the H1 incompatibility group.

Purpose of the Study:

• * To highlight the diminished efficacy of traditional antibiotics for typhoid fever due to MDR strains.
• * To identify ciprofloxacin as the current drug of choice for typhoid fever.
• * To report the emergence of chromosomal resistance to ciprofloxacin in MDR Salmonella typhi.

Main Methods:

• * Analysis of Salmonella typhi strains isolated from various geographical regions and patient populations.
• * Examination of resistance mechanisms, including plasmid-encoded resistance.
• * Clinical case observations of treatment outcomes with ciprofloxacin.

Main Results:

• * Chloramphenicol, ampicillin, and trimethoprim are no longer first-line treatments for typhoid fever due to widespread MDR strains.
• * Ciprofloxacin is now the recommended drug of choice for typhoid fever.
• * Chromosomally encoded resistance to ciprofloxacin has been identified in a small number of MDR Salmonella typhi strains, including cases with treatment failure.

Conclusions:

• * The emergence of ciprofloxacin resistance in MDR Salmonella typhi is a significant public health concern.
• * Prudent and limited use of ciprofloxacin is crucial to prevent further development and dissemination of resistance.
• * Continued surveillance and stewardship are essential to maintain the effectiveness of ciprofloxacin for treating typhoid fever.