COMPARATIVE MIC PROFILING OF COLISTIN AND POLYMYXIN B REVEALS SPECIES-SPECIFIC SUSCEPTIBILITY AND DILUTION DISCORDANCE AMONG GRAM-NEGATIVE BACTERIA

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Published: Apr 29, 2026
DOI: https://doi.org/10.69980/as.v12i2.6800
Keywords:
colistin, polymyxin B, minimum inhibitory concentration, Gram-negative bacteria, dilution discordance

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Dr. Bansari Yagnik Tank
Associate Professor, Department Of Microbiology, Dr. N. D. Desai Faculty of Medical Science and Research, Dharmsinh Desai University, Gujarat, India

Abstract

Resistance in Gram-negative bacteria has increased dependence on last-line drugs like colistin and polymyxin B, but their minimum inhibitory concentration (MIC) may differ across species. This study compared species-specific colistin and polymyxin B MIC profiles and quantified paired dilution agreement and discordance among Gram-negative bacterial isolates. A total of 160 isolates of Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. were included in the retrospective quantitative study. Medians, IQR's, MIC50 and MIC90 were used to characterize MIC distributions, and non-parametric tests were used to test species differences, paired MIC differences and correlations. Overall MIC50/MIC90 values were 0.25/16 for colistin and 0.125/0.5 for polymyxin B. Colistin MICs differed significantly across species (H = 9.346, p = 0.025), whereas polymyxin B MICs did not (p = 0.434). Paired MICs differed significantly (W = 67.5, p < 0.001; r = 0.838) and showed a moderate positive correlation (ρ = 0.580, p < 0.001). Agreement was 65.6% within ±1 dilution and 77.5% within ±2 dilutions, while 22.5% of pairs differed by more than two dilution steps. These findings demonstrate related but non-equivalent MIC patterns, supporting organism-specific interpretation of colistin and polymyxin B susceptibility.

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How to Cite
Dr. Bansari Yagnik Tank. (2026). COMPARATIVE MIC PROFILING OF COLISTIN AND POLYMYXIN B REVEALS SPECIES-SPECIFIC SUSCEPTIBILITY AND DILUTION DISCORDANCE AMONG GRAM-NEGATIVE BACTERIA. IJRDO-Journal of Applied Science, 12(2), 80-89. https://doi.org/10.69980/as.v12i2.6800
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Vol. 12 No. 2 (2026): IJRDO -Journal of Applied Science (ISSN: 2455-6653)
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References

1. Abavisani, M., Bostanghadiri, N., Ghahramanpour, H., Kodori, M., Akrami, F., Fathizadeh, H., ... & Rastegari-Pouyani, M. (2023). Colistin resistance mechanisms in Gram-negative bacteria: a Focus on Escherichia coli. Letters in Applied Microbiology, 76(2), ovad023.
2. Aslam, B., Asghar, R., Muzammil, S., Shafique, M., Siddique, A. B., Khurshid, M., ... & Baloch, Z. (2024). AMR and sustainable development goals: at a crossroads. Globalization and Health, 20(1), 73.
3. Bassetti, M., Righi, E., Carnelutti, A., Graziano, E., & Russo, A. (2018). Multidrug-resistant Klebsiella pneumoniae: challenges for treatment, prevention and infection control. Expert review of anti-infective therapy, 16(10), 749-761.
4. Bian, X., Liu, X., Hu, F., Feng, M., Chen, Y., Bergen, P. J., ... & Zhang, J. (2022). Pharmacokinetic/pharmacodynamic based breakpoints of polymyxin B for bloodstream infections caused by multidrug-resistant gram-negative pathogens. Frontiers in Pharmacology, 12, 785893.
5. Doymaz, M. Z., & Karaaslan, E. (2019). Comparison of antibacterial activities of polymyxin B and colistin against multidrug resistant Gram negative bacteria. Infectious Diseases, 51(9), 676-682.
6. Folgori, L., Bielicki, J., Heath, P. T., & Sharland, M. (2017). Antimicrobial-resistant Gram-negative infections in neonates: burden of disease and challenges in treatment. Current opinion in infectious diseases, 30(3), 281-288.
7. Huang, Y. S., Wang, J. T., Chuang, Y. C., Sheng, W. H., & Chang, S. C. (2025). Comparative analysis of colistin and polymyxin B minimal inhibitory concentrations in enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa. Journal of Infection and Public Health, 103091.
8. Ibrahim, S., Al-Saryi, N., Al-Kadmy, I. M., & Aziz, S. N. (2021). Multidrug-resistant Acinetobacter baumannii as an emerging concern in hospitals. Molecular biology reports, 48(10), 6987-6998.
9. Kunz Coyne, A. J., El Ghali, A., Holger, D., Rebold, N., & Rybak, M. J. (2022). Therapeutic strategies for emerging multidrug-resistant Pseudomonas aeruginosa. Infectious diseases and therapy, 11(2), 661-682.
10. Morrison, L., & Zembower, T. R. (2020). Antimicrobial resistance. Gastrointestinal Endoscopy Clinics, 30(4), 619-635.
11. Pitt, M. E., Elliott, A. G., Cao, M. D., Ganesamoorthy, D., Karaiskos, I., Giamarellou, H., ... & Coin, L. J. (2018). Multifactorial chromosomal variants regulate polymyxin resistance in extensively drug-resistant Klebsiella pneumoniae. Microbial genomics, 4(3), e000158.
12. Poirel, L., Jayol, A., & Nordmann, P. (2017). Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or chromosomes. Clinical microbiology reviews, 30(2), 557-596.
13. Qu, J., Qi, T. T., Qu, Q., Long, W. M., Chen, Y., Luo, Y., & Wang, Y. (2022). Polymyxin B-based regimens for patients infected with carbapenem-resistant gram-negative bacteria: clinical and microbiological efficacy, mortality, and safety. Infection and Drug Resistance, 1205-1218.
14. Radhakrishnan, S. P. (2024). Colistin and polymyxin -b data [Dataset]. Mendeley Data. https://doi.org/10.17632/V38YXVV99P.1
15. Sherry, N., & Howden, B. (2018). Emerging Gram negative resistance to last-line antimicrobial agents fosfomycin, colistin and ceftazidime-avibactam–epidemiology, laboratory detection and treatment implications. Expert review of anti-infective therapy, 16(4), 289-306.
16. Simon, V., Viswam, A., Alexander, P. S., James, E., & Sudhindran, S. (2023). Colistin versus polymyxin B: a pragmatic assessment of renal and neurological adverse effects and effectiveness in multidrug-resistant Gram-negative bacterial infections. Indian Journal of Pharmacology, 55(4), 229.
17. Tamma, P. D., Heil, E. L., Justo, J. A., Mathers, A. J., Satlin, M. J., & Bonomo, R. A. (2024). Infectious Diseases Society of America 2024 guidance on the treatment of antimicrobial-resistant gram-negative infections. Clinical infectious diseases, ciae403.
18. Torres, D. A., Seth-Smith, H. M., Joosse, N., Lang, C., Dubuis, O., Nüesch-Inderbinen, M., ... & Egli, A. (2021). Colistin resistance in Gram-negative bacteria analysed by five phenotypic assays and inference of the underlying genomic mechanisms. BMC microbiology, 21(1), 321.
19. Vaara, M. (2019). Polymyxin derivatives that sensitize Gram-negative bacteria to other antibiotics. Molecules, 24(2), 249.
20. Vardakas, K. Z., & Falagas, M. E. (2017). Colistin versus polymyxin B for the treatment of patients with multidrug-resistant Gram-negative infections: a systematic review and meta-analysis. International journal of antimicrobial agents, 49(2), 233-238.
21. Wolford, H., McCarthy, N. L., Baggs, J., Hatfield, K. M., Maillis, A., Olubajo, B., ... & Reddy, S. C. (2025). Antimicrobial-resistant infections in hospitalized patients. JAMA Network Open, 8(3), e2462059.