Colistin Resistance in Carbapenem-Resistant Klebsiella Pneumoniae Strains

Abstract

Objective: There is an increasing use of colistin consequent to increase in the infections caused by carbapenem-resistant Klebsiella pneumoniae. The present study was conducted to determine the minimum inhibitory concentration (MIC) of colistin and the resistance pattern of colistin in carbapenem-resistant K. pneumoniae (CRKP) strains in our intensive care unit (ICU).Methods: Antibiotic susceptibility testing for other antimicrobial agents was done by Kirby-Bauer disk diffusion method. MIC of colistin was determined by agar dilution method. The results of antibiotic susceptibility testing were interpreted as per Clinical Laboratory Standard Institute guidelines 2016 and MIC of colistin were interpreted as per European Committee on Antimicrobial susceptibility testing. The carbapenem resistance was phenotypically detected by modified hodge test and imipenem/imipenem ethylenediaminetetraacetic acid disk method.Results: Out of 518 K. pneumoniae, 329 were resistant to carbapenems, and 91 isolates showed resistance to colistin. The MIC of colistin ranged between 4 and >512 ug/ml and MIC 90 was 16 ug/L and MIC 50 was 4 ug/ml. A majority of the colistin-resistant isolates were found in multidisciplinary ICU (85/91). Conclusion:The emergence of colistin-resistant strains is a major problem due to limited treatment options for infections caused by CRKP carbapenemase producing K. pneumoniae. Colistin should not be used alone, combination therapy should be preferred.

A comparative study among different methods of detection of colistin resistant gram negative bacilli in a tertiary care hospital

“…In the present study, Klebsiella pneumoniae was most frequently isolated from respiratory specimen i.e., endotracheal tube secretion (n=6) and bronchial wash (n=2) which was followed by pus specimen (n=3), blood (n=2), urine (n=2) and sputum (n=2). Similar findings were reported [24] in their research. However Goel [10] reported all colistin resistant klebsiella pneumonia in blood samples followed by respiratory specimens, aspirates and pus.…”

“…The various samples with colistin resistance organisms in the present study was seen maximum in endotracheal tube secretion (34.3%), urine (18.7%) followed by bronchial wash (12.5%), pus (12.5%), blood (9.3%) and sputum (6.25%) which was comparable to the study by Bhasker et al [24] where they also found colistin resistance organisms maximum in tracheal secretion (33.73%) followed by blood (24.3%), urine (17.9%), pus (6.7%), bronchoalveolar lavage (6.4%), catheter tips (4.5%), fluid (3.95%) and tissue (2.4%). In the study by Arjun et al [9] also found urine sample (33%) as a major source of colistin resistant isolate followed by respiratory samples (20.8%), pus (16.67%), blood (6%) and also in cerebrospinal fluid (4.17%) whereas Pawar et al [8] reported colistin resistant bacilli from pus (42.3%), followed by catheter tip (19.7%), urine (16.7%), and endotracheal tube secretion (9.1%), sputum (9.1%) each.…”

“…Bacteraemia due to colistin resistance organsims was also reported from various studies [7,9,12,24,25,27] which correlated in the present study where colistin resistant isolate found was Klebsiella pneumoniae (n=2) followed by Pseudomonas aeruginosa (n=1). No colistin resistant Escherichia coli and Acinetobacter baumannii causing bacteraemia was isolated.…”

“…Other studies [7,9,10,22,24,25] also stated that colistin resistant Klebsiella pneumoniae as an emerging pathogen which was seen in the present study as well. On the contrary, Pawar et al [8] reported Pseudomonas aeruginosa as most common colistin resistant isolate followed by Acinetobacter baumannii whereas Jain S [11] reported Pseudomonas aeruginosa and Klebsiella pneumoniae as major organism with colistin resistance.…”

“…The patients from whom the colistin resistant isolates identified were mostly from neurosurgical ICU (25%) followed by nephrology ICU (25%) and orthopaedics icu. Similar patients were identified from the study by Bhasker et al [24]. Goel et al [10] also reported clusters of colistin resistant organisms mostly from gastro surgical department, head and neck surgery department and renal department.…”