INCIDENCE OF SALMONELLA INFECTION IN PEDIATRIC POPULATION IN SHAUKAT KHANUM MEMORIAL CANCER HOSPITAL AND RESEARCH CENTER, PAKISTAN

Abstract

Background: Despite the introduction of antibiotics significantly reducing the mortality associated with Salmonella Typhi infections, the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has created a critical public health challenge, particularly in endemic regions like Pakistan. The increasing resistance limits treatment options, complicates disease management, and underscores the need for continuous surveillance, especially among vulnerable pediatric populations including those with underlying malignancies.

Objective: This study aimed to assess the prevalence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Salmonella Typhi infections among pediatric cancer and non-cancer patients treated at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Pakistan.

Methods: A retrospective multicenter study was conducted over a one-year period from June 30, 2023, to May 31, 2024. Blood cultures were processed using the Bact/Alert system, and isolates were confirmed as Salmonella Typhi or Salmonella Paratyphi. Antimicrobial susceptibility testing was performed via the Kirby-Bauer disk diffusion method against ampicillin, chloramphenicol, co-trimoxazole, cefixime, ceftriaxone, azithromycin, imipenem, meropenem, and ciprofloxacin, following Clinical Laboratory Standards Institute (CLSI) 2020 guidelines. MDR was defined as resistance to ampicillin, chloramphenicol, and co-trimoxazole, whereas XDR included MDR with additional resistance to fluoroquinolones and third-generation cephalosporins.

Results: Out of 3,146 positive blood cultures, 864 isolates (27.5%) were confirmed as Salmonella species. Among these, 60 cases (7%) involved pediatric cancer patients, and 804 (93%) were post-chemotherapy or non-cancer patients. Resistance profiling revealed 61 isolates (7.1%) as MDR, 409 isolates (47.3%) as XDR, and 394 isolates (45.6%) as non-MDR/XDR. Fluoroquinolone resistance was observed in 88% of isolates, while minimal resistance was noted against azithromycin, imipenem, and meropenem.

Conclusion: This study highlights a concerning prevalence of MDR and XDR Salmonella Typhi among pediatric patients, particularly emphasizing the pressing need for strengthened antibiotic stewardship, vigilant surveillance, and proactive vaccination strategies to mitigate the spread of drug-resistant strains.