In clinical medicine,<unk> s are most frequently prescribed on the basis of a person's symptoms and medical guidelines. This method of<unk>  selection is called empiric therapy, and it is based on knowledge about what bacteria cause an infection, and to what<unk> s bacteria may be sensitive or resistant. For example, a simple urinary tract infection might be treated with trimethoprim/sulfamethoxazole. This is because Escherichia coli is the most likely causative bacterium, and may be sensitive to that combination<unk> . However, bacteria can be resistant to several classes of<unk> s. This resistance might be because a type of bacteria has intrinsic resistance to some<unk> s, because of resistance following past exposure to<unk> s, or because resistance may be transmitted from other sources such as plasmids.<unk>  provides information about which<unk> s are more likely to be successful and should therefore be used to treat the infection.<unk>  is also conducted at a population level in some countries as a form of screening. This is to assess the background rates of resistance to<unk> s (for example with methicillin-resistant Staphylococcus aureus), and may influence guidelines and public health measures.
Antibiotic sensitivity testing
Microbiological culture
Blood culture
Sputum culture
Culture conversion
Digital contact tracing
Empiric therapy
Bacteriology