Colistin is an antibiotic that has been considered as a last resort for treating infections caused by antibiotic-resistant bacteria. However, in recent years, concerns have been raised about the emergence of bacteria that are resistant to colistin, which could pose a significant threat to public health. This article will provide an overview of colistin, its mechanism of action, the emergence of colistin-resistant bacteria, and potential strategies for addressing this problem.
Colistin, also known as polymyxin E, is a peptide antibiotic that was first isolated from the bacteria Paenibacillus polymyxa in 1947. Colistin works by binding to the lipid component of bacterial cell membranes, disrupting their integrity and causing cell death. It is primarily used to treat infections caused by Gram-negative bacteria, such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, which are often resistant to other antibiotics.
However, the use of colistin has been limited due to its toxicity and potential side effects, such as damage to the kidneys and nervous system. In recent years, colistin has been used more frequently as a last resort for treating infections caused by antibiotic-resistant bacteria, particularly carbapenem-resistant Enterobacteriaceae (CRE).
The emergence of colistin-resistant bacteria is a major concern for public health. In 2015, a new gene called mcr-1 was identified in China, which confers resistance to colistin. Since then, several other variants of the mcr gene have been identified in various countries, including the mcr-2, mcr-3, mcr-4, and mcr-5 genes.
The mcr genes are usually carried on mobile genetic elements, such as plasmids, which can transfer between different bacterial species, spreading the resistance to colistin. The mcr genes have been found in various types of bacteria, including Escherichia coli, Salmonella enterica, and Klebsiella pneumoniae. In addition, other mechanisms of colistin resistance have also been identified, such as modifications to the bacterial outer membrane, which can prevent colistin from binding to the lipid component.
The emergence of colistin-resistant bacteria has significant implications for public health, as it limits the treatment options for infections caused by antibiotic-resistant bacteria. In addition, the spread of colistin resistance between different bacterial species could lead to the development of pan-resistant bacteria, which are resistant to all available antibiotics.
To address this problem, several strategies have been proposed. One approach is to limit the use of colistin and other antibiotics in agriculture, as the use of antibiotics in livestock can contribute to the spread of antibiotic-resistant bacteria. In addition, there is a need to develop new antibiotics and alternative therapies for treating infections caused by antibiotic-resistant bacteria.
In conclusion, the emergence of colistin-resistant bacteria is a significant concern for public health, as it limits the treatment options for infections caused by antibiotic-resistant bacteria. The spread of colistin resistance between different bacterial species highlights the need for effective strategies to address this problem. Limiting the use of antibiotics in agriculture and developing new antibiotics and alternative therapies could be important steps towards addressing the problem of colistin resistance.
