ANTIBIOTIC RESISTANCE PATTERNS OF SALMONELLA SPECIES AND SHIFTS IN EMPIRICAL TREATMENT: A STUDY FROM AYUB TEACHING HOSPITAL ABBOTTABAD, KPK, PAKISTAN

Abstract

Background: Typhoid fever remains a critical public health issue in many developing countries, particularly due to the rise of antibiotic-resistant strains, which are aggravated by the frequent and often inappropriate use of antibiotics. This study evaluates the antibiogram patterns of Salmonella species isolated from blood cultures of patients admitted to a tertiary care hospital in Abbottabad, Khyber Pakhtunkhwa, Pakistan. The aim is to analyze current resistance trends and provide updated insights into antimicrobial susceptibility, thereby contributing to improved management strategies for typhoid fever in this region.
Materials and Methods: This retrospective cross-sectional study was conducted using data from a tertiary care government hospital in Abbottabad, Khyber Pakhtunkhwa, Pakistan. Patients diagnosed with enteric fever were identified based on positive blood cultures for Salmonella species. The study included a comprehensive analysis of 1,250 cases recorded between January 2022 and July 2023. Data collected included patient demographics, seasonal distribution, and detailed antibiotic susceptibility profiles of the isolated Salmonella strains.
Results: Out of the total 1,250 cases, males made up the majority, accounting for 62% (775 cases). A significant proportion of the cases were clustered among children and young adults aged between 8 and 28 years. The highest incidence was observed during the spring and summer months, particularly from April to September. In terms of Salmonella Typhi isolates, notable resistancewas detected against first-line antibiotics, including amoxicillin/clavulanate (77.8%), co- trimoxazole/trimethoprim-sulfamethoxazole (63.4%), and chloramphenicol (83.5%). Resistance to ceftriaxone and ciprofloxacin was also significant, at 76.9% and 48.9%, respectively.

However, certain antibiotics demonstrated strong sensitivity profiles, with meropenem (98.1%), doripenem (99.0%), imipenem (96.9%), ertapenem (95.8%), polymyxin B (98.7%), colistin (97.5%), and tigecycline (96.8%) showing high effectiveness. The sensitivity rates for amikacin and gentamicin were 88.9% and 79.6%, respectively. Azithromycin, on the other hand, showed a concerning sensitivity rate of 64.3%. The antibiogram of Salmonella demonstrated marked shifts in resistance patterns, raising concerns about evolving therapeutic challenges.

Conclusion: This study highlights a higher incidence of typhoid fever among males, with a pronounced seasonal peak occurring during the spring and summer months. The most affected age group was between 8 and 28 years. The Salmonella isolates demonstrated substantial resistance to conventional first-line antibiotics, as well as to ciprofloxacin and third-generation cephalosporins. Additionally, azithromycin showed reduced sensitivity when compared to amikacin, gentamicin, and meropenem. Based on these findings, the study suggests that empirical treatment for typhoid fever in this region should prioritize the use of amikacin, gentamicin, and meropenem. The research emphasizes the need for regular monitoring of Salmonella resistance patterns, improved antibiotic stewardship, public health campaigns for awareness, and the implementation of vaccination programs to enhance prevention strategies.