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Frequency of colistin resistance in Pseudomonas aeruginosa: first report from Peru
Marjhory Zarate1, Delsy Barrantes1, Diego Cuicapuza2
1Laboratorio de Resistencia Antimicrobiana e Inmunopatología, Universidad Peruana Cayetano Heredia, Lima, Perú.
Abstract:
This study aimed to determine the frequency of colistin resistance in Pseudomonas aeruginosa isolates obtained from three healthcare facilities in Lima and cryopreserved at the Laboratorio de Resistencia Antimicrobianos e Inmunopatología of the Universidad Peruana Cayetano Heredia (UPCH). The colistin broth disk elution method was used for the phenotypic identification of colistin resistance. We detected the expression of the mcr-1 gene by using the phenotypic diffusion method with combined colistin and ethylenediaminetetraacetic acid (EDTA) disks; and polymerase chain reaction (PCR) was used for molecular identification of the gene. Of the 97 isolates, 7 (7.2%) were resistant to colistin; however, none carried the mcr-1 gene. This is the first report from Peru on clinical isolates of colistin-resistant Pseudomonas aeruginosa, which suggests the need for implementation of appropriate methodologies for the epidemiological surveillance of colistin-resistant pathogens.
Insights
Colistin resistance in Pseudomonas aeruginosa was found in 7.2% of clinical isolates from Lima, Peru. However, the mcr-1 gene, a common cause of resistance, was not detected in these resistant strains.
Area of Science:
- Clinical microbiology
- Antimicrobial resistance research
- Infectious diseases
Background:
- Colistin is a critical antibiotic for treating multidrug-resistant Gram-negative infections.
- Pseudomonas aeruginosa is an opportunistic pathogen frequently associated with healthcare-associated infections.
- Emergence of colistin resistance, particularly through the mcr-1 gene, is a significant global health concern.
Purpose of the Study:
- To determine the prevalence of colistin resistance in Pseudomonas aeruginosa isolates from Peruvian healthcare facilities.
- To investigate the presence of the mcr-1 gene in colistin-resistant Pseudomonas aeruginosa isolates.
- To establish baseline data for antimicrobial resistance surveillance in Peru.
Main Methods:
- Phenotypic detection of colistin resistance using the colistin broth disk elution method.
- Detection of mcr-1 gene expression via phenotypic diffusion with colistin-EDTA disks.
- Molecular confirmation of the mcr-1 gene using polymerase chain reaction (PCR).
Main Results:
- Out of 97 Pseudomonas aeruginosa isolates, 7 (7.2%) exhibited resistance to colistin.
- None of the colistin-resistant isolates harbored the mcr-1 gene.
- This study represents the first report of colistin-resistant Pseudomonas aeruginosa clinical isolates in Peru.
Conclusions:
- Colistin resistance in Pseudomonas aeruginosa exists in Peruvian clinical settings.
- The absence of the mcr-1 gene in resistant isolates suggests alternative resistance mechanisms may be prevalent.
- Enhanced surveillance strategies are crucial for monitoring colistin-resistant pathogens in Peru.
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