Question

Although in vitro tests of susceptibility to antibiotics are widely used and considered useful, there have been cases in which the in vitro tests have not predicted how well the drug would work when administered to humans. This works both ways. Some antibiotics that are effective in vitro fail when administered to humans, and some antibiotics that test resistant in vitro actually work when used therapeutically. Give some explanations for both of these outcomes

Answer 1

In vitro testing is done generally on a cellline grown using tissue culture method. This cell line behaves like a cells/tissue in the body but not exactly the same.

When a drug is administered in human there are many factors or interactions which takes place which were not present in in vitro cell line. As the systems of the body are so complex with many enzymes and controlling factors, they may receive the drug in a better manner or reject it all together when compared to cell line.