PCR-Based Screening for mcr-7, mcr-8, and mcr-9 in Acinetobacter baumannii-Acinetobacter calcoaceticus Complex Isolates from Veterinary and Environmental Sources.
- 1Department of Veterinary Microbiology and Immunology, Federal Rural University of Rio de Janeiro (UFRRJ), BR-465, Km 7, Seropédica 23897-000, RJ, Brazil.
- 2Laboratory of Research on Hospital Infection, Oswaldo Cruz Institute (Fiocruz), Avenida Brasil, 4365, Manguinhos, Rio de Janeiro 21040-900, RJ, Brazil.
- 3Department of Medicine, University of Vassouras, Avenida Expedicionário Oswaldo de Almeida Ramos, 280, Centro, Vassouras 27700-000, RJ, Brazil.
Abstract
Background/objectives
The Acinetobacter baumannii-calcoaceticus (Acb) complex comprises opportunistic pathogens of increasing relevance in human and veterinary medicine due to their capacity to acquire multidrug resistance. colistin, a last-resort antimicrobial for carbapenem-resistant A. baumannii (CRAB), is increasingly challenged by the emergence of resistance determinants, including those encoded by the mobilized colistin resistance (mcr) gene family. This study aimed to screen for mcr genes in Acb complex isolates recovered from animal and environmental sources in Rio de Janeiro State, Brazil.Methods
Thirty-five isolates obtained from dogs, cats, horses, and soil between 2018 and 2020 were genotypically identified using multiplex PCR. Of these, 23 successfully recovered isolates were screened for mcr variants (mcr-1 to mcr-9) by multiplex PCR.Results
Five isolates (21.7%) yielded amplicons of expected sizes consistent with the presence of mcr-associated determinants, including two consistent with mcr-7, one with mcr-8, and two with mcr-9. Because amplicon sequencing and phenotypic colistin susceptibility testing were not performed, these findings should be interpreted as preliminary molecular screening results.Conclusions
These findings indicate the presence of PCR-detectable mcr-associated genetic targets in isolates from animal and environmental sources, highlighting the need for further molecular characterization and integrated surveillance under a One Health framework.
Related
- Validation of NG-TEST Acineto-5 for the Detection of OXA Carbapenemases, NDM, and VIM in the Acinetobacter calcoaceticus-baumannii Complex and beyond
- Virulence determinants in multidrug-resistant Acinetobacter baumannii: comparative phenotypic and genomic analysis of clinical and patient-environmental isolates
- Outbreak of carbapenem-resistant Acinetobacter baumannii in post–haematopoietic stem cell transplantation patients potentially caused by drinking water contamination
- Community-acquired Acinetobacter baumannii pneumonia in Southern Vietnam : A retrospective cohort study
- When the Antibiogram Offers Nothing Else: Ceftriaxone–Sulbactam–Disodium EDTA With Intravenous Colistin in Two Neonates With Metallo‐β‐Lactamase‐Producing Acinetobacter baumannii Meningitis
BibTeX
@article{holmstrom2026pcrbased,
title = {{PCR-Based Screening for mcr-7, mcr-8, and mcr-9 in Acinetobacter baumannii-Acinetobacter calcoaceticus Complex Isolates from Veterinary and Environmental Sources.}},
author = {Thérèsse C N Holmström and Luana O Silva and Sophia M P O Costa and Leticia B Pinto and Mário T Makita and Cláudio M Rocha-de-Souza and Shana de M O Coelho and Dayanne A de Melo and Irene S Coelho and Miliane M S de Souza},
journal = {Antibiotics (Basel, Switzerland)},
year = {2026},
month = oct,
doi = {10.3390/antibiotics15101040},
url = {https://europepmc.org/article/MED/42938779},
note = {CC BY},
}
RIS
TY - JOUR
TI - PCR-Based Screening for mcr-7, mcr-8, and mcr-9 in Acinetobacter baumannii-Acinetobacter calcoaceticus Complex Isolates from Veterinary and Environmental Sources.
AU - Thérèsse C N Holmström
AU - Luana O Silva
AU - Sophia M P O Costa
AU - Leticia B Pinto
AU - Mário T Makita
AU - Cláudio M Rocha-de-Souza
AU - Shana de M O Coelho
AU - Dayanne A de Melo
AU - Irene S Coelho
AU - Miliane M S de Souza
PY - 2026
DA - 2026/10/21
JO - Antibiotics (Basel, Switzerland)
DO - 10.3390/antibiotics15101040
UR - https://europepmc.org/article/MED/42938779
AB - Background/objectives The Acinetobacter baumannii-calcoaceticus (Acb) complex comprises opportunistic pathogens of increasing relevance in human and veterinary medicine due to their capacity to acquire multidrug resistance. colistin, a last-resort antimicrobial for carbapenem-resistant A. baumannii (CRAB), is increasingly challenged by the emergence of resistance determinants, including those encoded by the mobilized colistin resistance (mcr) gene family. This study aimed to screen for mcr genes in Acb complex isolates recovered from animal and environmental sources in Rio de Janeiro State, Brazil.Methods Thirty-five isolates obtained from dogs, cats, horses, and soil between 2018 and 2020 were genotypically identified using multiplex PCR. Of these, 23 successfully recovered isolates were screened for mcr variants (mcr-1 to mcr-9) by multiplex PCR.Results Five isolates (21.7%) yielded amplicons of expected sizes consistent with the presence of mcr-associated determinants, including two consistent with mcr-7, one with mcr-8, and two with mcr-9. Because amplicon sequencing and phenotypic colistin susceptibility testing were not performed, these findings should be interpreted as preliminary molecular screening results.Conclusions These findings indicate the presence of PCR-detectable mcr-associated genetic targets in isolates from animal and environmental sources, highlighting the need for further molecular characterization and integrated surveillance under a One Health framework.
SN - 2079-6382
ER -