Chromosomally encoded and plasmid-mediated polymyxins resistance in Acinetobacter baumannii: a huge public health
William Gustavo Lima1, Mara Cristina Alves2, Waleska Stephanie Cruz3
1Laboratory of Medical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Rua Sebastião Gonçalves Coelho, 400, Divinopolis, Minas Gerais, 35501-293, Brazil. williamgustavo_1992@hotmail.com.
Abstract:
Acinetobacter baumannii is an opportunistic pathogen associated with nosocomial and community infections of great clinical relevance. Its ability to rapidly develop resistance to antimicrobials, especially carbapenems, has re-boosted the prescription and use of polymyxins. However, the emergence of strains resistant to these antimicrobials is becoming a critical issue in several regions of the world because very few of currently available antibiotics are effective in these cases. This review summarizes the most up-to-date knowledge about chromosomally encoded and plasmid-mediated polymyxins resistance in A. baumannii. Different mechanisms are employed by A. baumannii to overcome the antibacterial effects of polymyxins. Modification of the outer membrane through phosphoethanolamine addition, loss of lipopolysaccharide, symmetric rupture, metabolic changes affecting osmoprotective amino acids, and overexpression of efflux pumps are involved in this process. Several genetic elements modulate these mechanisms, but only three of them have been described so far in A. baumannii clinical isolates such as mutations in pmrCAB, lpxACD, and lpsB. Elucidation of genotypic profiles and resistance mechanisms are necessary for control and fight against resistance to polymyxins in A. baumannii, thereby protecting this class for future treatment.
Insights
Acinetobacter baumannii is developing resistance to polymyxins, a critical antibiotic class. Understanding resistance mechanisms is vital for future treatments against this opportunistic pathogen.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Acinetobacter baumannii is a significant opportunistic pathogen causing nosocomial and community infections.
- Rapid development of carbapenem resistance has increased reliance on polymyxins.
- Emerging polymyxin resistance in A. baumannii poses a critical global health threat due to limited alternative treatments.
Purpose of the Study:
- To review current knowledge on polymyxin resistance mechanisms in Acinetobacter baumannii.
- To summarize both chromosomally encoded and plasmid-mediated resistance.
- To highlight the importance of understanding genotypic profiles for combating resistance.
Main Methods:
- Literature review of current research on polymyxin resistance in A. baumannii.
- Synthesis of information on various resistance mechanisms.
- Identification of key genetic elements involved in resistance.
Main Results:
- A. baumannii employs multiple strategies to resist polymyxins, including outer membrane modifications (phosphoethanolamine addition, LPS loss).
- Other mechanisms involve metabolic changes and efflux pump overexpression.
- Key genetic mutations identified in clinical isolates include pmrCAB, lpxACD, and lpsB.
Conclusions:
- Understanding the diverse resistance mechanisms is crucial for controlling polymyxin resistance in A. baumannii.
- Identifying genotypic profiles aids in combating resistance.
- Preserving the efficacy of polymyxins is essential for future therapeutic options.
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