in the presence of different stresses, bacteria regulate growth and become dormant. In the presence of antibiotics part of bacterial population become drug tolerant. I would like to know the differences in respect to metabolism, proteomes etc.
There are sensitive and resistant bacteria to antibiotics. Resistance is controlled by many factors. Sensitive bacteria subjecting to low doses of certain antibiotic can tolerate such low concentrations and still survive or can be exposed to mutations. Of course if the organism became a mutant strain, it has a little metabolic difference from wild strain. This should be studied practically as it differes according to strain used.
Dormancy/latency can also be considered from a different perspective. Dormant bacteria can form spores to reside in the environment or in low nutrient condition and then revert back when the condition (nutrient, temperature, pH etc.) becomes favourable. Latency, on the other hand, can be considered as a bacteria when staying inside an organ and becoming a stealth killer. Ex- Bacteria inside a granuloma (as seen in the case of Mycobacterium tuberculosis), chronic typhoidal Salmonella sp. infection (when the bacteria stays inside a macrophage and makes it their home).
Thus, dormant/latent bacteria are not always the exact same thing. Bacteria can become dormant in sub-lethal/sub-optimal doses of anti-bacterials, some of them can become resistant after prolonged sub-culturing. This is what happens when someone does not complete his/her antibiotic medication. It is not always the case though.
Bacteria can also become resistant upon acquiring a resistant gene (in the form of a plasmid or chromosomal recombination) also.
I hope I have managed to help you a bit.
hi Ashutosh,
Dormancy/latency are like going to hibernation when the conditions are not suitable for growth like drought conditions, high osmotic stress, etc. Whenever these conditions becomes favourable, bacteria will revert back to its active form but antibiotic resistance is completely different as the growth conditions does not changes but a new stress i.e, antibiotic is introduced in the bacterial environment. Here the bacteria does not go into dormancy but if it has the capability to somehow remove that antibiotic or nullify its effect, it grows almost normally and we call them drug tolerant or drug resistant bacteria. These drug resistance are generally acquired through plasmids or by mutations.
Now Persisters are a subpopulation of otherwise regular bacterial cells which have very low metabolism and are highly drug resistant. They are generally formed by pathogenic bacteria and are very common in conditions where bacteria are protected by biofilm against antibiotics or to host immune system.
Persisters are formed due to some mutations in regular cells (hip mutants in case of P. aeruginosa and C. albicans) while dormancy is very well regulated phenomenon.
If you want to go deep into it then go through the link below:
https://www.ncbi.nlm.nih.gov/pubmed/23090599
Hope this will help you.
Thanks Debaki for explaining Dormancy/Latency in detail. Thanks Bharat for description on persisters. I think persister (drug tolerance) is temporary phenomenon of a part of bacterial population that may become normal cells (drug sensitive) when conditions revert.
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