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Open AccessArticle

Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae

1
Facultad de Farmacia, Departamento de Farmacia, Universidad de Concepción, Concepción 4030000, Chile
2
Laboratorio de Investigación en Agentes Antibacterianos (LIAA), Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción 4070386, Chile
3
Millennium Nucleus for Collaborative Research on Bacterial Resistance, MICROB-R, Concepción 4070386, Chile
4
Departamento de Prevención y Salud Pública, Facultad de Odontología, Universidad de Concepción, Concepción 4070386, Chile
5
Departamento de Medicina Interna, Facultad de Medicina, Universidad de Concepción, Concepción 4070386, Chile
*
Authors to whom correspondence should be addressed.
Microorganisms 2020, 8(9), 1279; https://doi.org/10.3390/microorganisms8091279
Received: 29 July 2020 / Revised: 14 August 2020 / Accepted: 20 August 2020 / Published: 21 August 2020
Colistin-heteroresistant (CST-HR) Enterobacterales isolates have been identified recently, challenging the clinical laboratories since routine susceptibility tests fail to detect this phenotype. In this work we describe the first CST-HR phenotype in extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates in South America. Additionally, we determine the genomic mechanisms of colistin heteroresistance in these strains. The CST-HR phenotype was analyzed by the population analysis profile (PAP) method, and mutations associated with this phenotype were determined by whole-genome sequencing (WGS) and the local BLAST+ DB tool. As a result, 8/60 isolates were classified as CST-HR according to the PAP method. From WGS, we determined that the CST-HR isolates belong to three different Sequence Types (STs) and four K-loci: ST11 (KL15 and KL81), ST25 (KL2), and ST1161 (KL19). We identified diverse mutations in the two-component regulatory systems PmrAB and PhoPQ, as well as a disruption of the mgrB global regulator mediated by IS1-like and IS-5-like elements, which could confer resistance to CST in CST-HR and ESBL-producing isolates. These are the first descriptions in Chile of CST-HR in ESBL-producing K. pneumoniae isolates. The emergence of these isolates could have a major impact on the effectiveness of colistin as a “last resort” against these isolates, thus jeopardizing current antibiotic alternatives; therefore, it is important to consider the epidemiology of the CST-HR phenotype. View Full-Text
Keywords: Colistin heteroresistance; Klebsiella pneumoniae; extended-spectrum β-lactamases Colistin heteroresistance; Klebsiella pneumoniae; extended-spectrum β-lactamases
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MDPI and ACS Style

Morales-León, F.; Lima, C.A.; González-Rocha, G.; Opazo-Capurro, A.; Bello-Toledo, H. Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae. Microorganisms 2020, 8, 1279. https://doi.org/10.3390/microorganisms8091279

AMA Style

Morales-León F, Lima CA, González-Rocha G, Opazo-Capurro A, Bello-Toledo H. Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae. Microorganisms. 2020; 8(9):1279. https://doi.org/10.3390/microorganisms8091279

Chicago/Turabian Style

Morales-León, Felipe; Lima, Celia A.; González-Rocha, Gerardo; Opazo-Capurro, Andrés; Bello-Toledo, Helia. 2020. "Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae" Microorganisms 8, no. 9: 1279. https://doi.org/10.3390/microorganisms8091279

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