FREQUENCY OF EXTENSIVELY DRUG-RESISTANT TYPHOID FEVER AND ASSOCIATED FACTORS AMONG CHILDREN PRESENTING TO A TERTIARY CARE HOSPITAL IN KARACHI, PAKISTAN

Abstract

Background: Typhoid fever remains a significant public health challenge in Pakistan, particularly among children. The emergence of extensively drug-resistant (XDR) Salmonella Typhi, which is resistant to first-line antibiotics, fluoroquinolones, and third-generation cephalosporins, has severely limited treatment options and raised concerns about untreatable infections. Local epidemiological data are essential to guide clinical management and public health interventions.

Objective: To determine the frequency of extensively drug-resistant (XDR) Salmonella Typhi and Salmonella Paratyphi among clinically suspected pediatric typhoid fever patients presenting to a tertiary care hospital in Karachi, Pakistan.

Methods: This descriptive cross-sectional study was conducted in the Department of Pediatrics at Dr. Ruth K.M. Pfau Civil Hospital, Karachi, from February to August 2021. A total of 138 children aged 1 month to 12 years with clinically suspected typhoid fever were enrolled using non-probability consecutive sampling. Blood culture and antimicrobial susceptibility testing were performed, and isolates were classified according to CLSI guidelines. XDR typhoid was defined as resistance to chloramphenicol, ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, and ceftriaxone.

Results: The mean age of participants was 6.41 ± 2.40 years, with females comprising 51.4% of the sample. Only 30.4% of children had received typhoid vaccination. Blood culture confirmed typhoid fever in all 138 patients, and 74 (53.6%) were identified as having XDR typhoid. Antimicrobial resistance was alarmingly high: ampicillin (91.3%), ceftriaxone (64.5%), chloramphenicol (60.9%), ciprofloxacin (58.7%), and trimethoprim-sulfamethoxazole (53.6%). Significant associations with XDR typhoid included male gender (p=0.007), low maternal education (p<0.001), poor socioeconomic status (p<0.001), lack of immunization (p<0.001), tap water use (p=0.003), and symptoms of nausea/vomiting, loss of appetite, and cough (p<0.001).

Conclusion: More than half of pediatric typhoid cases were XDR, reflecting a substantial burden of antimicrobial resistance. Vaccination status, maternal education, socioeconomic conditions, and water source were significantly associated with XDR typhoid. Strengthening vaccine coverage, improving water and sanitation infrastructure, promoting antimicrobial stewardship, and maintaining continuous surveillance are essential to control the spread of resistant typhoid and improve pediatric health outcomes.