Susceptibility Testing

Common Questions

Would a doctor ever prescribe an antibiotic without or before performing a culture?
Yes. In certain situations, a doctor may choose a therapy while a culture is incubating and in others, he may prescribe therapy without ever ordering a culture. While it is impossible to predict which microorganism is causing an infection unless a culture is performed, some organisms are seen more frequently than others. For instance, most urinary tract infections (UTIs) are caused by the bacterium Escherichia coli. Knowing this, a doctor may rely on his experience to deduce which “bug” is most likely to be causing the infection and to choose a drug that is effective in most cases. In addition, there are certain life-threatening infections that must be treated immediately, with no time to wait for the results of a culture. In other instances, a culture would not be attempted because a specimen may not be obtainable (such as with otitis media – ear infections) or the pathogen may not be easily isolated from other flora in the specimen (such as with community-acquired pneumonia). In these cases, the doctor chooses therapy to cover the most common pathogens that cause these infections.