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Rapid detection of colistin-resistant Klebsiella pneumoniae using MALDI-TOF MS peak-based assay

Cesira Giordano¹, Simona Barnini¹

¹SD Ospedaliera di Microbiologia, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy.

Journal of Microbiological Methods

|November 16, 2018

Abstract:

Carbapenemase-producing Klebsiella pneumoniae has become a worldwide recognized cause of nosocomial infections and requires urgent public health attention. The main reason of this concern is the increasing resistance to all the last-resort antibiotics, including colistin. The ideal methodology for colistin susceptibility testing still remains undefined. However, the emergence of colistin as one of the last-option treatments requires a reliable method to determine the susceptibility profile of resistant isolates. The aim of the present study was to evaluate the impact of detecting colistin resistance in Klebsiella pneumoniae isolates using MALDI-TOF MS in clinical routine practice. For this reason, 139 isolates of K. pneumoniae were collected during 2015-2017 from patients hospitalized at Pisa University Hospital. Colonies suspected to be colistin resistant were identified using MALDI-TOF MS (Bruker Daltonik GmbH, Bremen, Germany) following a protein extraction protocol. Strains were previously wholly genome sequenced. To create a customized database entry and to generate classifying algorithm models, 1.112 mass spectra were collected. In relation to their mass signals and intensities, a two dimensional peak distribution was created. The recognition capability of the algorithm based on two manually selected mass peaks was 91,8%, while cross validation was 87,6%. The proportion of correctly classified colistin-resistant K. pneumoniae was 91% and colistin-susceptible was 73%. The emergence of colistin-resistant Gram-negative organisms has a dramatic impact on patient outcomes. Our study, based on MALDI-TOF MS technology, offers rapid preliminary results on colistin resistance profile coupled with bacteria identification.

Insights

Carbapenemase-producing Klebsiella pneumoniae resistance to colistin is a growing threat. MALDI-TOF MS shows promise for rapid detection of colistin resistance in clinical settings, aiding patient care.

Area of Science:

Microbiology
Clinical Diagnostics
Antimicrobial Resistance

Background:

Carbapenemase-producing Klebsiella pneumoniae (CPKP) is a significant cause of hospital-acquired infections.
Increasing resistance to last-resort antibiotics like colistin necessitates reliable susceptibility testing.
Colistin is a critical treatment option for multidrug-resistant Gram-negative infections.

Purpose of the Study:

To evaluate the effectiveness of MALDI-TOF MS for detecting colistin resistance in Klebsiella pneumoniae.
To assess the clinical utility of MALDI-TOF MS in routine practice for colistin resistance profiling.
To develop and validate an algorithm for classifying colistin resistance using MALDI-TOF MS data.

Main Methods:

Analysis of 139 Klebsiella pneumoniae isolates collected from 2015-2017.
Identification of suspected colistin-resistant colonies using MALDI-TOF MS with a protein extraction protocol.
Whole genome sequencing of strains and collection of 1,112 mass spectra for database customization and algorithm development.

Main Results:

The algorithm achieved 91.8% recognition capability and 87.6% cross-validation.
Correct classification rates for colistin-resistant K. pneumoniae were 91%, and for colistin-susceptible strains were 73%.
MALDI-TOF MS provided rapid preliminary results for colistin resistance alongside bacterial identification.

Conclusions:

MALDI-TOF MS technology offers a rapid method for preliminary colistin resistance detection in Klebsiella pneumoniae.
This approach can aid in timely clinical decisions for patients with infections caused by resistant Gram-negative organisms.
The study highlights the potential of MALDI-TOF MS to improve the management of antimicrobial resistance in healthcare settings.

Read full analysis

Keywords:

Colistin resistance Genetic algorithm MALDI-TOF MS Mass peaks Proteome

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