An Assessment of the Current Trends of Antibiotic Resistance of Salmonella typhi against 1st Line Antimicrobial Agents in Metropolitan City of Karachi: An Observational, Cross Sectional Descriptive Study

Abstract

Objectives: The objective of this study was to assess current trends of antibiotic resistance against S. typhi in Pakistani population.

Methodology: This was a cross-sectional, observational descriptive research conducted in various diagnostic facilities in Karachi-Pakistan from January 2019 to November 2020.

The study was approved by the IRB through letter no. JUW/IERB/035/2021. A data of 1223 patients, who were reported positive for typhoid fever, was collected from various diagnostic facilities with in the area. Clinical isolates were examined for culture sensitivity by using BACTEC™ and Versa TREK™. Isolates of the Salmonella typhi and para typhi were recovered from blood of the patients. The collected data was analyzed using SPSS version 22.0.

Results: Among all isolates, 92.7% (n=1134) isolates were identified as S. typhi and the remaining 7.3% (n=89) as S. paratyphi.  Study population suffering from typhoid fever were 58.5% (n=716) male trailed by 41.5% (n=507) female. Similarly, among 1223 clinical isolates, 14.2% (n=174) were non-resistant, 5.4% (n=66) were multi-drug resistant (MDR), 56.4% (n=690) were extensive drug resistant (XDR), 12.7% (n=155) were moving towards multi-drug resistant species trend and 5.7% (n=70) were heading towards XDR. A further 5.6% (n=68) were moving towards ESBL positive typhoid fever. Moreover, 49.1% of the S. typhi isolates were found to be resistant to all the first line antibiotics agents (ampicillin, chloramphenicol and co-trimoxazole) with only 15.2% found to be sensitive to all first line antibiotics drugs. 22% were resistant to either two 1st line drugs whereas 10.6%, 1.9% and 1.6% were found to be resistant to ampicillin, co-trimoxazole and chloramphenicol alone therapies respectively. XDR cases with resistance to even 3^rd-line drugs for typhoid fever have documented.

Conclusion: Strains of Salmonella typhi in Karachi are resistant to most of the drugs recommended by local infectious disease society for treatment of typhoid. This is alarming for healthcare policy makers because of lack of newer drugs discovered for treatment of typhoid fever and pathogens isolated for this highly infectious disease being resistant to most of the recommended anti-microbial agents.

Keywords: Typhoid fever, Drug resistance, XDR, Salmonella typhi