COLISTIN AGAR; EVALUATION OF A NOVEL DIAGNOSTIC APPROACH TO DETECTION OF COLISTIN RESISTANCE

  • Saad Ali Combined Military Hospital Multan/National University of Medical Sciences (NUMS) Pakistan
  • Wajid Hussain Armed Forces Institute of Pathology/National University of Medical Sciences (NUMS) Rawalpindi Pakistan
  • Farooq Ahmad Armed Forces Institute of Pathology/National University of Medical Sciences (NUMS) Rawalpindi Pakistan
  • Raja Kamran Afzal Combined Military Hospital Multan/National University of Medical Sciences (NUMS) Pakistan
  • Irfan Ali Mirza Armed Forces Institute of Pathology/National University of Medical Sciences (NUMS) Rawalpindi Pakistan
  • Mariam Sarwar Armed Forces Institute of Pathology/National University of Medical Sciences (NUMS) Rawalpindi Pakistan
Keywords: Agar Dilution, Broth Micro Dilution, Colistin Resistance, Gram Negative Bacilli, Minimum inhibitory Concentration, Multi Drug Resistant

Abstract

Objective: To determine the diagnostic accuracy of Colistin agar for detection of Colistin resistance in clinical isolates of MultiDrug Resistant Gram-Negative Bacilli.

Study Design: Cross-sectional validation study.

Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi Pakistan, from Feb to Aug 2019.

Methodology: A total of 100 Multi-Drug Resistant Gram-Negative Bacilli in clinical isolates were included. Isolates were identified using Gram stain, Catalase, Oxidase, API 20E, and API 20NE. After approval from the institutional ethical review committee, Colistin susceptibility was determined simultaneously by Colistin agar and Broth Micro Dilution Minimum Inhibitory Concentration method as per CLSI. For susceptibility criteria, EUCAST guidelines were followed. Results were validated with the gold standard test, i.e., Broth Micro Dilution.

Results: Out of 100 Multi-Drug Resistant clinical isolates, the distribution was K. pneumoniae n=60, E.coli n=16, A. baumannii n=11, C. freundii n=8, and E. cloacae n=5. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of Colistin agar for detection of Colistin resistance, keeping Broth Micro Dilution Minimum Inhibitory Concentration method as the gold standard was 96.67%, 97.14%, 93.55%, 98.55%, and 97%, respectively.

Conclusion: Colistin agar has excellent diagnostic accuracy for the detection of colistin resistance with standardized inoculum density. Due to its ease of use, cost-effectiveness, and accurate results, it can be used in lab setups deficient in manpower and advanced equipment for Broth Micro Dilution or genetic sequencing.

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Published
2022-01-14
How to Cite
Ali, S., Hussain, W., Ahmad, F., Afzal, R., Mirza, I., & Sarwar, M. (2022). COLISTIN AGAR; EVALUATION OF A NOVEL DIAGNOSTIC APPROACH TO DETECTION OF COLISTIN RESISTANCE. PAFMJ, 71(6), 2249-52. https://doi.org/10.51253/pafmj.v71i6.7223
Section
Original Articles

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