Typhoid in Laos: An 18-Year Perspective.

Area of Science:

• Infectious Diseases
• Epidemiology
• Microbiology

Background:

• Typhoid fever is endemic in Southeast Asia, yet data from Laos is scarce.
• Laos lacks a national typhoid vaccination program, and access to clean water remains a challenge for many.
• Understanding the epidemiology and antimicrobial resistance of Salmonella Typhi is crucial for public health in Laos.

Purpose of the Study:

• To describe the epidemiology of Salmonella Typhi infections in Laos.
• To analyze antimicrobial susceptibility patterns of Salmonella Typhi isolates over an 18-year period.
• To provide evidence for public health strategies, including potential typhoid vaccine introduction.

Main Methods:

• Retrospective analysis of blood cultures positive for Salmonella Typhi from Mahosot Hospital, Vientiane, and associated facilities (February 2000-December 2018).
• Inclusion of data from Vientiane, four provincial hospitals, and one typhoid outbreak investigation.
• Assessment of antimicrobial susceptibility for various antibiotics, including fluoroquinolones.

Main Results:

• A total of 913 (1.5%) Salmonella Typhi isolates were identified from 60,384 blood cultures.
• The majority of isolates (79.3%) were susceptible to all tested antibiotics; 6.5% were multidrug-resistant (MDR), primarily linked to one outbreak.
• Fluoroquinolone resistance was observed in 1.4% of isolates. Admissions peaked during the dry season (March-June).

Conclusions:

• This study presents the first comprehensive epidemiological data on typhoid fever in Laos.
• Currently, multidrug and fluoroquinolone resistance are not major issues, but ongoing surveillance and antibiotic stewardship are vital.
• Further cost-effectiveness analysis is needed to guide decisions on typhoid vaccine introduction in Laos.