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Lucidi M, Imperi F, Artuso I, Capecchi G, Spagnoli C, Visaggio D, Rampioni G, Leoni L, Visca P. Phage-mediated colistin resistance in Acinetobacter baumannii. Drug Resist Updat 2024; 73:101061. [PMID: 38301486 DOI: 10.1016/j.drup.2024.101061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/03/2024]
Abstract
AIMS Antimicrobial resistance is a global threat to human health, and Acinetobacter baumannii is a paradigmatic example of how rapidly bacteria become resistant to clinically relevant antimicrobials. The emergence of multidrug-resistant A. baumannii strains has forced the revival of colistin as a last-resort drug, suddenly leading to the emergence of colistin resistance. We investigated the genetic and molecular basis of colistin resistance in A. baumannii, and the mechanisms implicated in its regulation and dissemination. METHODS Comparative genomic analysis was combined with genetic, biochemical, and phenotypic assays to characterize Φ19606, an A. baumannii temperate bacteriophage that carries a colistin resistance gene. RESULTS Ф19606 was detected in 41% of 523 A. baumannii complete genomes and demonstrated to act as a mobile vehicle of the colistin resistance gene eptA1, encoding a functional lipid A phosphoethanolamine transferase. The eptA1 gene is coregulated with its chromosomal homolog pmrC via the PmrAB two-component system and confers colistin resistance when induced by low calcium and magnesium levels. Resistance selection assays showed that the eptA1-harbouring phage Ф19606 promotes the emergence of spontaneous colistin-resistant mutants. CONCLUSIONS Φ19606 is an unprecedented example of a self-transmissible phage vector implicated in the dissemination of colistin resistance.
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Affiliation(s)
- Massimiliano Lucidi
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy; NBFC, National Biodiversity Future Center, piazza Marina 61, 90133 Palermo, Italy.
| | - Francesco Imperi
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy; NBFC, National Biodiversity Future Center, piazza Marina 61, 90133 Palermo, Italy; Santa Lucia Foundation IRCCS, Via Ardeatina 306/354, 00179 Rome, Italy
| | - Irene Artuso
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Giulia Capecchi
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Cinzia Spagnoli
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Daniela Visaggio
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy; NBFC, National Biodiversity Future Center, piazza Marina 61, 90133 Palermo, Italy; Santa Lucia Foundation IRCCS, Via Ardeatina 306/354, 00179 Rome, Italy
| | - Giordano Rampioni
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy; Santa Lucia Foundation IRCCS, Via Ardeatina 306/354, 00179 Rome, Italy
| | - Livia Leoni
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Paolo Visca
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy; NBFC, National Biodiversity Future Center, piazza Marina 61, 90133 Palermo, Italy; Santa Lucia Foundation IRCCS, Via Ardeatina 306/354, 00179 Rome, Italy.
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