+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Assessing Colistin Resistance by Phenotypic and Molecular Methods in Carbapenem-resistant Enterobacterales in a Tertiary Care Hospital in Pakistan


      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          Members of Enterobacterales are very common pathogens, which continue to show resistance to many antibiotics. Carbapenem performed well for some time. Colistin was the final hope for the carbapenem-resistant Enterobacterales, but resistance against it has virtually tied the clinician’s hands, especially when it comes to treating critically ill patients.


          Detection of colistin resistance by the agar method as well as by the polymerase chain reaction (mobilized colistin resistance-1 gene) in carbapenem-resistant Enterobacterales.

          Materials and Methods

          A cross-sectional study from Dec 2019 to Dec 2020 was conducted at the Department of Microbiology, Army Medical College, National University of Medical Sciences Rawalpindi Pakistan. Antimicrobial susceptibility of Enterobacterales was determined according to the Kirby–Bauer disc diffusion method except for colistin. Colistin agar was used, in concentrations of 2 µg/mL and 4 µg/mL. Results were interpreted according to Clinical and Laboratory Standards Institute guidelines 2020. Mobilized colistin-resistant-1 gene in the carbapenem resistant Enterobacterales was detected by performing real-time polymerase chain reaction assay.


          Among the 172 carbapenem-resistant Enterobacterales 18 isolates were resistant using the colistin agar test. Whereas by molecular method colistin resistance was detected among 10 isolates that carried mobilized colistin resistance 1 gene, making the frequency of the MCR-1 gene 5.81%. Seventy percent of isolates were from paired blood samples. Eight patients, from whom the colistin resistant gene was isolated expired.


          Colistin resistance is a very serious issue and should not be missed in a clinical microbiology laboratory. The phenotypic agar test method is an excellent option for routine use, as it combines ease of performance with affordable cost. However, molecular methods are essential for the detection of mobilized colistin resistance gene (1–9) for epidemiological purposes.

          Related collections

          Most cited references31

          • Record: found
          • Abstract: found
          • Article: not found

          Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study.

          Until now, polymyxin resistance has involved chromosomal mutations but has never been reported via horizontal gene transfer. During a routine surveillance project on antimicrobial resistance in commensal Escherichia coli from food animals in China, a major increase of colistin resistance was observed. When an E coli strain, SHP45, possessing colistin resistance that could be transferred to another strain, was isolated from a pig, we conducted further analysis of possible plasmid-mediated polymyxin resistance. Herein, we report the emergence of the first plasmid-mediated polymyxin resistance mechanism, MCR-1, in Enterobacteriaceae.
            • Record: found
            • Abstract: found
            • Article: not found

            Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases.

            Klebsiella pneumoniae carbapenemases (KPCs) were originally identified in the USA in 1996. Since then, these versatile β-lactamases have spread internationally among Gram-negative bacteria, especially K pneumoniae, although their precise epidemiology is diverse across countries and regions. The mortality described among patients infected with organisms positive for KPC is high, perhaps as a result of the limited antibiotic options remaining (often colistin, tigecycline, or aminoglycosides). Triple drug combinations using colistin, tigecycline, and imipenem have recently been associated with improved survival among patients with bacteraemia. In this Review, we summarise the epidemiology of KPCs across continents, and discuss issues around detection, present antibiotic options and those in development, treatment outcome and mortality, and infection control. In view of the limitations of present treatments and the paucity of new drugs in the pipeline, infection control must be our primary defence for now. Copyright © 2013 Elsevier Ltd. All rights reserved.
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Epidemiology and Diagnostics of Carbapenem Resistance in Gram-negative Bacteria

              Abstract Carbapenem resistance in gram-negative bacteria has caused a global epidemic that continues to grow. Although carbapenemase-producing Enterobacteriaceae have received the most attention because resistance was first reported in these pathogens in the early 1990s, there is increased awareness of the impact of carbapenem-resistant nonfermenting gram-negative bacteria, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Moreover, evaluating the problem of carbapenem resistance requires the consideration of both carbapenemase-producing bacteria as well as bacteria with other carbapenem resistance mechanisms. Advances in rapid diagnostic tests to improve the detection of carbapenem resistance and the use of large, population-based datasets to capture a greater proportion of carbapenem-resistant organisms can help us gain a better understanding of this urgent threat and enable physicians to select the most appropriate antibiotics.

                Author and article information

                Infect Drug Resist
                Infect Drug Resist
                Infection and Drug Resistance
                10 October 2022
                : 15
                : 5899-5904
                [1 ]Department of Microbiology Army Medical College (National University of Medical Sciences) , Rawalpindi, Pakistan
                Author notes
                Correspondence: Warda Furqan, House No. 4, Street No.18, Sector H DHA2, Islamabad, Pakistan, Tel +92-336-5141818, Email warda_khan28@yahoo.com
                © 2022 Furqan et al.

                This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms ( https://www.dovepress.com/terms.php).

                Page count
                Figures: 1, Tables: 2, References: 31, Pages: 6
                Original Research

                Infectious disease & Microbiology
                carbapenem-resistant enterobacterales,colistin agar test,enterobacterales,mobilized colistin resistant-1 gene,phenotypic method,real time polymerase chain reaction


                Comment on this article