Unveiling colistin resistance in extensively drug-resistant microorganisms among ICU patients of tertiary care hospital Karachi, Pakistan


  • Sadia Talib Karachi Institute of Medical Sciences, Karachi Pakistan
  • Abeera Ahmed The Pakistan Navy Ship Rahat Hospital, Karachi Pakistan
  • Syeda Hira Abid Karachi Institute of Medical Sciences, Karachi Pakistan
  • Tahira Assad Karachi Institute of Medical Sciences, Karachi Pakistan
  • Muhammad Nizamuddin Dow International Medical College, Karachi Pakistan
  • Shaista Sharif Teshil Headquarters Hospital, Shahpur Pakistan




Objective: To determine the prevalence of extensively drug-resistant (XDR) microorganisms in the intensive care unit (ICU) of a tertiary care hospital in Karachi and to identify the presence of colistin resistance (CLR) among these XDR isolates.

Material and Methods: A cross sectional study was carried out in the ICU of a tertiary care hospital from August 2022 to February 2023 and various clinical samples of XDR Gram negative bacilli (GNB) were collected from ICU. These specimens were processed by following the guidelines established by the Clinical and Laboratory Standards Institute (CLSI), Agar and broth microdilution methods were used to assess the colistin susceptibility of XDR isolates.

Results: The study focused on 100 extensively drug-resistant (XDR) specimens. K. Pneumoniae dominated (32%), followed by E. coli (23). Among the 100 XDR, 89% were colistin susceptible, and 11% were resistant, tested by agar and broth microdilution. Of the 11% CLR, P. aeruginosa was most common, with the highest resistance in urine specimens. Colistin resistance was highest for P. aeruginosa (45%), followed by A. baumannii (18%), E. coli (18%), K. Pneumoniae (9%), and K. oxytoca (9%). CLR isolates were mainly (27%) from urine.

Conclusion: Prolonged hospital stays and antibiotic pressure can lead to CLR development. Labs should monitor XDR closely, implementing measures to minimize antibiotic resistance. Controlling colistin resistance through stewardship is crucial.

Keywords: Extensively drug resistant, Colistin resistant, Minimum inhibitory concentration, Nasobronchial lavage


Endimiani A, Ramette A, Rhoads DD, Jacobs MR. The evolving role of the clinical microbiology laboratory in identifying resistance in Gram-negative bacteria: an update. Infect Dis Clin North Am. 2020; 34(4): 659-76. DOI: https://doi.org/10.1016/j.idc.2020.08.001

Pogue JM, Cohen DA, Marchaim D. Editorial commentary: Polymyxin-resistant Acinetobacter baumannii: urgent action needed. Clin Infect Dis. 2015 May 1;60(9):1304-7. DOI: https://doi.org/10.1093%2Fcid%2Fciv044

Ayukekbong JA, Ntemgwa M, Atabe AN. The threat of antimicrobial resistance in developing countries: causes and control strategies. Antimicrobial Resistance & Infection Control. 2017; 6(1):1-8. DOI: https://doi.org/10.1186/s13756-017-0208-x

Abbas S, Sabir AU, Khalid N, Sabir S, Khalid S, Haseeb S, et al. Frequency of extensively drug-resistant gram-negative pathogens in a tertiary care hospital in Pakistan. Cureus. 2020; 12(12). e11914. DOI: https://doi.org/10.7759%2Fcureus.11914

Bilal H, Khan MN, Rehman T, Hameed MF, Yang X. Antibiotic resistance in Pakistan: a systematic review of past decade. BMC Infect Dis. 2021; 21(1):244. DOI: https://doi.org/10.1186/s12879-021-05906-1

World Health Organization. Antimicrobial stewardship programmes in health-care facilities in low-and middle-income countries: A WHO practical toolkit.

Mlynarcik P, Kolar M. Molecular mechanisms of polymyxin resistance and detection of mcr genes. Biomed Pap Med Fac Palacky Univ Olomouc Czech Repub. 2019; 163(1).28-38. DOI: https://doi.org/10.5507/bp.2018.070

Pfennigwerth N, Kaminski A, Korte-Berwanger M, Pfeifer Y, Simon M, Werner G, et al. Evaluation of six commercial products for colistin susceptibility testing in Enterobacterales. Clin Microbiol Infect. 2019; 25(11): 1385-9.

DOI: https://doi.org/10.1016/j.cmi.2019.03.017

Balouiri M, Sadiki M, Ibnsouda SK. Methods for in vitro evaluating antimicrobial activity: A review. J Pharmaceutical Analysis. 2016; 6(2): 71-9. DOI: https://doi.org/10.1016/j.jpha.2015.11.005

Wiegand I, Hilpert K, Hancock RE. Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances. Nature Protocols. 2008; 3(2): 163-75. DOI: https://doi.org/10.1038/nprot.2007.521

Furqan W, Ali S, Usman J, Hanif F, Naeem A, Nasrullah A, Tayyab N. Assessing Colistin resistance by phenotypic and molecular methods in carbapenem-resistant enterobacterales in a tertiary care hospital in Pakistan. Infect Drug Resist. 2022: 5899-904. DOI: https://doi.org/10.2147/idr.s376490

Clinical and Laboratory Standards Institute (CLSI). Methods for dilution of antimicrobial susceptibility tests for bacteria that grow aerobically; Approved standard, 11th ed. Document M07- A11. Wayne, PA. CLSI; 2018; 1-11

Browne K, Chakraborty S, Chen R, Willcox MD, Black DS, Walsh WR, et al. A new era of antibiotics: The clinical potential of antimicrobial peptides. Int J Mol Sci. 2020; 21(19): 7047. DOI: https://doi.org/10.3390%2Fijms21197047

Garcia-Vidal FJ, Fernández-Domínguez AI, Martin-Moreno L, Zhang HC, Tang W, Peng R, et al. Spoof surface plasmon photonics. Rev Mod Phys. 2022; 94(2): 025004. DOI:https://doi.org/10.1103/RevModPhys.94.025004

Qamar S, Shaheen N, Shakoor S, Farooqi J, Jabeen K, Hasan R. Frequency of colistin and fosfomycin resistance in carbapenem-resistant Enterobacteriaceae from a tertiary care hospital in Karachi. Infect Drug Resist. 2017: 231-6.

Abd El-Baky RM, Masoud SM, Mohamed DS, Waly NG, Shafik EA, Mohareb DA, et al. Prevalence and some possible mechanisms of colistin resistance among multidrug-resistant and extensively drug-resistant Pseudomonas aeruginosa. Infect Drug Resist. 2020: 323-32. DOI: https://doi.org/10.2147%2FIDR.S238811

Coșeriu RL, Mare AD, Toma F, Vintilă C, Ciurea CN, Togănel RO, et al. Uncovering the resistance mechanisms in extended-drug-resistant pseudomonas aeruginosa clinical isolates: insights from gene expression and phenotypic tests. Microorganisms. 2023; 11(9): 2211. DOI:https://doi.org/10.3390/microorganisms11092211

Bir R, Gautam H, Arif N, Chakravarti P, Verma J, Banerjee S, et al. Analysis of colistin resistance in carbapenem-resistant Enterobacterales and XDR Klebsiella pneumoniae. Ther Adv Infect Dis. 2022; 9: 20499361221080650. DOI: https://doi.org/10.1177/20499361221080650

Rojas LJ, Salim M, Cober E, Richter SS, Perez F, Salata RA, et al. Colistin resistance in carbapenem-resistant Klebsiella pneumoniae: laboratory detection and impact on mortality. Clin Infect Dis. 2017; 64(6): 711-8.

DOI: https://doi.org/10.1093/cid/ciw805

Sana F, Satti L, Zaman G, Ikram A, Gardezi AH, Khadim MT. In Vitro comparison of disk diffusion method and agar dilution method for sensitivity of polymyxin B against Multi Drug Resistant Acinetobacter Baumannii. Pak Armed Forces Med J. 2019; 69(5): 998-1003.

Matthaiou DK, Michalopoulos A, Rafailidis PI, Karageorgopoulos DE, Papaioannou V, Ntani G, et al. Risk factors associated with the isolation of colistin-resistant gram-negative bacteria: A matched case-control study. Crit Care Med. 2008; 36(3): 807-11. DOI:https://doi.org/10.1097/ccm.0b013e3181652fae

Kontopidou F, Giamarellou H, Katerelos P, Maragos A, Kioumis I, Trikka-Graphakos E, et al. Infections caused by carbapenem-resistant Klebsiella pneumoniae among patients in intensive care units in Greece: A multi-centre study on clinical outcome and therapeutic options. Clin Microb Infect. 2014; 20(2): O117-23. DOI: https://doi.org/10.1111/1469-0691.12341

Ghasemian A, Mobarez AM, Peerayeh SN, Abadi AT, Khodaparast S, Nojoomi F. Report of plasmid-mediated colistin resistance in Klebsiella oxytoca from Iran. Rev Med Microbiol. 2018; 29(2): 59-63. DOI:https://doi.org/10.1097/MRM.0000000000000134

Uzairue LI, Rabaan AA, Adewumi FA, Okolie OJ, Folorunso JB, Bakhrebah MA, et al. Global prevalence of colistin resistance in Klebsiella pneumoniae from bloodstream infection: A systematic review and meta-analysis. Pathogens. 2022; 11(10): 1092. DOI: https://doi.org/10.3390/pathogens11101092




How to Cite

Talib S, Ahmed A, Abid SH, Assad T, Nizamuddin M, Sharif S. Unveiling colistin resistance in extensively drug-resistant microorganisms among ICU patients of tertiary care hospital Karachi, Pakistan . Pak J Pathol [Internet]. 2024 Mar. 29 [cited 2024 Apr. 23];35(1):7-12. Available from: https://pakjpath.com/index.php/Pak-J-Pathol/article/view/800