An antibiogram or sensitivity test determines the susceptibility of organisms involved in various infections to antimicrobial drugs when the organism's susceptibility cannot be predicted based on its identity. Antibiotic susceptibility is sometimes used to monitor hospital infections such as methicillin-resistant Staphylococcus aureus (MRSA) and evaluate resistance to new antimicrobial drugs.
There are no interpretative criteria for all bacteria. The division into sensitive, moderately sensitive, and resistant categories is based on the levels of antibiotics achieved in the serum of individuals with normal renal and hepatic function. Antibiotics that accumulate in the urine can be effective for urinary tract infections even when the microbes are classified as resistant. Conversely, medicines not penetrating the tissues with a poor blood supply may be ineffective even when microbes are classified as susceptible.
Depending on their sensitivity to specific antibiotic concentrations, microorganisms are characterized as:
Sensitive: This category implies that the infection caused by the particular microbial strain can be treated with the appropriate dosage of the antimicrobial agent for this type of infection with the specific microbial species unless contraindicated.
Moderately Sensitive: This category includes strains of microbes that are not clearly sensitive.
Resistant: Antimicrobial strains belonging to this class are not inhibited by the usual systemic concentrations of the antimicrobial agent at the typical dosage, and/or specific mechanisms of microbial resistance (e.g., β-lactamases) may be present.
Important Note
Laboratory test results are the most critical parameter for diagnosing and monitoring all pathological conditions. Between 70 to 80% of diagnostic decisions are based on laboratory tests. Correctly interpreting laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be analyzed based on each case and family history, clinical findings, and the results of other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
