Antibiotic resistance among Salmonella enterica serovars Typhi and Paratyphi A in Pakistan (2001-2006)

  • Rumina Hasan Department of Pathology and Microbiology, Aga Khan University Hospitals, Karachi
  • Afia Zafar Department of Pathology and Microbiology, Aga Khan University Hospitals, Karachi
  • Zohair Abbas Department of Pediatrics, Aga Khan University Hospitals, Karachi
  • Vikram Mahraj Department of Pathology and Microbiology, Aga Khan University Hospitals, Karachi
  • Faisal Malik Department of Pathology and Microbiology, Aga Khan University Hospitals, Karachi
  • Anita Zaidi Department of Pediatrics, Aga Khan University Hospitals, Karachi

Abstract

Objectives: To compare antimicrobial resistance in S. Typhi and S. Paratyphi A isolates from Pakistan.
Methods: Blood samples were collected through > 175 laboratory collection points in major cities and towns across the country. The study included 3,671 S. Typhi and 1,475 S. Paratyphi A isolates (2001-2006). Multidrug resistance (MDR) was defined as resistance to first-line agents co-trimoxazole, chloramphenicol and ampicillin.
Results: In total, 79.3% S. Typhi and 59.9% S. Paratyphi A were isolated from patients under 15 years of age. During the study period, the MDR rate increased in S. Typhi (34.2 to 48.5% p<0.001), but decreased in S. Paratyphi A (44.5 to 8.6% p<0.001). Quinolone resistance (MIC>1μg/ml) increased in both S. Typhi (1.6 to 64.1% p<0.001) and S. Paratyphi A (0 to 47% p<0.001). The increase in the proportion of strains showing high level quinolone resistance (MIC >4μg/ml) was greater in S. Paratyphi A when compared to S. Typhi. Resistance to first-line drugs was higher in those <15 years of age whereas quinolone resistance was higher in older patients.
Conclusion: Differences between S. Typhi and S. Paratyphi A, in terms of evolution of resistance to first-line agents and to quinolones, are evident in this population. The rapid increase in quinolone resistance in S. Paratyphi A when compared to S. Typhi is concerning and requires further study.
Published
2008-08-01
How to Cite
Hasan R, Zafar A, Abbas Z, Mahraj V, Malik F, Zaidi A (2008) Antibiotic resistance among Salmonella enterica serovars Typhi and Paratyphi A in Pakistan (2001-2006). The Journal Of Infection In Developing Countries 2 (04): 289-294. https://doi.org/10.3855/jidc.224
Section
Original Articles

Keywords

Salmonella, Antibiotic resistance, Typhi, Paratyphi, Pakistan