TRENDS AND PATTERNS OF ANTIMICROBIAL RESISTANCE IN TYPHOID FEVER: A DIVISION - BASED REGIONAL SURVEILLANCE STUDY

Abstract

Background: Antimicrobial resistance (AMR) in Salmonella enterica serovar Typhi (typhoid fever) has escalated into a public health crisis, especially with the emergence of extensively drug-resistant (XDR) strains. Pakistan has experienced a large XDR typhoid outbreak since 2016, raising concerns about treatment options and transmission. Understanding resistance patterns across demographics is vital for guiding interventions.
Objective: To analyze the trends in AMR among typhoid fever cases, with emphasis on age-group and gender differences in resistance profiles, based on surveillance data from a tertiary care hospital in Punjab, Pakistan.
Methods: We conducted a retrospective analysis of laboratory-confirmed typhoid cases recorded in 2024. Patient data included age (categorized as <5, 5–14, ≥15 years), gender, district of residence, and antibiotic susceptibility results. Isolates were classified as non-resistant, multidrug-resistant (MDR), or XDR according to standard definitions. We summarized resistance frequencies for key antibiotics and examined the distribution of XDR cases by age, gender, district, and month of diagnosis.
Results: A total of 36 typhoid cases were analyzed. Males constituted 61% of cases and children 5–14 years were the most affected age group (44% of cases). XDR typhoid was identified in 16 cases (44%), MDR in 8 (22%), and 12 cases (33%) were fully susceptible to first-line drugs. XDR prevalence was highest in 5–14-year-olds (68.8% of cases in that group), whereas <5-year-olds had the lowest proportion of XDR (11%). Male patients had a higher occurrence of XDR (50% of male cases) compared to females (36%). Geographically, 80% of cases originated from Faisalabad district, indicating a local outbreak concentration. Resistance to fluoroquinolones was ubiquitous (67% of isolates resistant to ciprofloxacin), alongside high rates of resistance to first-line agents ampicillin and co-trimoxazole (61% each). Notably, 15 isolates (42%) were resistant to ceftriaxone, defining the XDR phenotype, and worrying levels of azithromycin (19%) and meropenem (22%) resistance were observed. Monthly trends showed a mid-year surge in cases, peaking in July–August 2024, during which XDR cases also spiked.
Conclusion: Our surveillance data highlight a substantial burden of drug-resistant typhoid in Punjab, marked by disproportionate impact on school-aged children and males. The co-occurrence of resistance to all standard oral therapies in many isolates underscores the urgency of sustained control measures. Public health responses should prioritize typhoid conjugate vaccine coverage in vulnerable age groups, strengthen water and sanitation infrastructure, and enforce prudent antibiotic use to curtail the spread of XDR typhoid.