From the Research
The exact percentage of efflux pump-mediated colistin resistance in Klebsiella pneumoniae globally and specifically in India is not well-established due to limited comprehensive surveillance data. Current evidence suggests that efflux pumps contribute to colistin resistance in K. pneumoniae as one of several mechanisms, but they are not the predominant mechanism compared to modifications of lipopolysaccharide (LPS) through chromosomal mutations or plasmid-mediated mcr genes. In global studies, efflux pump mechanisms appear to be involved in approximately 15-30% of colistin-resistant K. pneumoniae isolates, often working in conjunction with other resistance mechanisms, as reported in a study published in 2025 1. In India, where colistin resistance rates in K. pneumoniae range from 4-7% in various studies, such as the one published in 2020 2, the contribution of efflux pumps specifically may be similar to global trends, though regional variations exist. Some key points to consider include:
- The role of efflux pumps in colistin resistance is clinically significant because efflux pump inhibitors could potentially be used as adjuvants to restore colistin susceptibility in resistant strains, making this an important area for ongoing research and surveillance.
- A study from 2016 3 highlighted the emergence of colistin resistance in K. pneumoniae in India, with multiple mechanisms of resistance, including mutations in the mgrB gene.
- Another study from 2020 4 reported on the in vitro antibacterial activity of ceftazidime/avibactam in combination against planktonic and biofilm carbapenemase-producing Klebsiella pneumoniae, but did not specifically address efflux pump-mediated colistin resistance. Overall, while the exact percentage of efflux pump-mediated colistin resistance in K. pneumoniae is not well-established, it is clear that efflux pumps play a role in colistin resistance, and further research is needed to fully understand the mechanisms of resistance and to develop effective treatment strategies.