Probiotics are the live beneficial microbes that obtain for desired outcomes, such as prevention of diseased state or improvement in general health outcome observed in host organisms. Probiotics can be either bacteria or fungi. Most probiotic organisms are lactic acid bacteria (LAB), which comprise a wide range of genera and include a considerable number of species, especially Lactobacillus, Bifidobacterium, and Enterococcus species. Probiotic bacteria can be epiphytes, endophytes, or rhizospheric bacteria. There are plant probiotics as well as human or animal probiotics, where animal probiotics are the majority.
Nowadays, there is a trend of using probiotics instead of antibiotics due to their higher safety. But there are certain probiotics that contain antibiotic-resistant genes. The hidden danger in this trend is that the genes that are responsible for antibiotic resistance can be horizontally transferred to other bacterial strains, especially pathogen genomes. Horizontal gene transfer occurs through three main genetic mechanisms: transformation, conjugation, and transduction. Once transferred, the genes and pathogens continue to evolve, often resulting in bacteria with greater resistance.
There have been several clinical incidents, including treatment failures and eventually extending to both hospital morbidities as well as mortalities, caused by pathogens with antibiotic resistant genes. Lactobacillus is a very good example of a probiotic bacteria genus which consists of antibiotic resistant genes. According to recent studies, most of the Lactobacillus strains contain at least 11 tetracycline resistant genes, which were able to transfer horizontally between Lactobacillus strains as well as to different gram-positive bacteria, including pathogens such as Staphylococcus strains. Apart from that, Lactobacillus strains, which are multi-drug resistant mediated, have a high chance of acquiring antibiotic resistance and receiving antibiotic resistant genes from other bacterial strains. This phenomenon can also happen in probiotic strains which have not been studied yet.
Figure 1 - Mechanisms of bacterial horizontal gene transfer
There is no mechanism to eliminate the antibiotic resistance effect of probiotics. But these genes can be screened according to a properly recognized procedure to reduce the effect of antibiotic resistance. This is a crucial safety hurdle that a certain probiotic should pass before being used as a safe probiotic. Educating the public about this double-edged sword effect is a current need for the betterment of the community.
References
Shuhadha, M. F. F., Panagoda, G. J., Madhujith, T., & Jayawardana, N. W. I. A. (2017). Evaluation of probiotic attributes of Lactobacillus sp. isolated from cow and buffalo curd samples collected from Kandy. Ceylon Medical Journal, 62(3).
Ruiza, D., Agaras, B., de Werrab, P., Wall, L. G., & Valverde, C. (2011). Characterization and screening of plant probiotic traits of bacteria isolated from rice seeds cultivated in Argentina. The Journal of Microbiology, 49(6), 902-912.
Burmeister, A. R. (2015). Horizontal gene transfer. Evolution, medicine, and public health, 2015(1), 193.
Gueimonde, M., Sánchez, B., de los Reyes-Gavilán, C. G., & Margolles, A. (2013). Antibiotic resistance in probiotic bacteria. Frontiers in microbiology, 4, 202.
Image courtesy
Featured image – https://theconversation.com/how-to-train-the-bodys-own-cells-to-combat-antibiotic-resistance-106052
Figure 1 – https://www.researchgate.net/publication/361748873/figure/fig4/AS:1184084101472259@1659319057983/Mechanisms-of-horizontal-gene-transfer-where-bacterial-DNA-can-be-transferred-from-one_W640.jpghttps://www.curioustem.org/stem-articles/horizontal-gene-transfer