Minimal Inhibitory Concentrations Of Azithromycin In Typhoidal Salmonella Isolated In Tertiary Care Setting


  • Anam Tariq Department of Pathology, Combined Military Hospital Lahore/ National University of Medical Sciences (NUMS) Pakistan
  • Irfan Ali Mirza Department of Pathology, Armed Forces Institute of Pathology / National University of Medical Sciences (NUMS) Rawalpindi Pakistan
  • Qanita Fahim Department of Pathology, Combined Military Hospital Chunian / National University of Medical Sciences (NUMS) Pakistan
  • Ayesha Bashir Department of Pathology, Combined Military Hospital Lahore/ National University of Medical Sciences (NUMS) Pakistan
  • Shafqat hussain Department of Pathology, Combined Military Hospital Lahore/ National University of Medical Sciences (NUMS) Pakistan
  • Chahat Hussain Department of Pathology, Combined Military Hospital Lahore/ National University of Medical Sciences (NUMS) Pakistan



Azithromycin, Minimum inhibitory concentration, Salmonella typhi


Objective: To determine the variations in minimal inhibitory concentrations (MIC) of Azithromycin amongst Salmonella typhi isolates.

Study Design: Cross-sectional study.

Place and Duration of Study: Department of Microbiology, Combined Military Hospital, Lahore Pakistan, from Jan to Dec 2020.

Methodology: Three hundred and eighty-four samples yielding the growth of Salmonella typhi were processed. Antibiotic susceptibility testing was done using the Kirby-Bauer Disk Diffusion technique, and the MIC of Azithromycin was determined using the E-strip method. Clinical and Laboratory Standards Institute (CLSI) recommended that MIC breakpoints be used for susceptibility testing of Azithromycin.

Results: Of 384 tested isolates, 103(26.8%) were multidrug-resistant (MDR). Resistance to Ciprofloxacin was as high as 367(95.6%) isolates, whereas extensively drug-resistant (XDR) isolates were calculated to be 204(53.1%). No resistance against Azithromycin was observed. All the isolates were in the susceptible MIC range of 0.5 and 8 μg/ml. The lowest MIC observed was 0.5 μg/ml by 12(5%) of the isolates. The highest MIC value of 8 μg/ml was observed in 6(1.5%) isolates, all of which were XDR. 231(60.2%) isolates had one μg/ml MIC, followed by MIC 4 μg/ml of 72(18.8%) isolates. The mean MIC value of all the isolates was calculated to be 1.82±1.3μg/ml.

Conclusion: The rise in XDR Salmonella typhi could lead to Azithromycin resistance. Antimicrobial stewardship is of prime importance, and Azithromycin MICs should be reported to keep the trends in check.


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How to Cite

Tariq A, Mirza IA, Fahim Q, Bashir A, hussain S, Hussain C. Minimal Inhibitory Concentrations Of Azithromycin In Typhoidal Salmonella Isolated In Tertiary Care Setting. Pak Armed Forces Med J [Internet]. 2024 Apr. 27 [cited 2024 May 24];74(2):265-8. Available from:



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