Final answer:
Culture and sensitivity testing from a surgical site infection identifies the bacteria and their antibiotic sensitivities, aiding in targeted treatment. Microscopic characteristics help identify bacterial species, while antimicrobial susceptibility testing informs on effective antibiotics.
Step-by-step explanation:
The culture and sensitivity testing performed on a swab from a postoperative surgical site infection allows the care team to identify the type of bacteria causing the infection and to determine which antibiotics the bacteria are sensitive or resistant to. By looking at the bacteria under a microscope, characteristics such as shape, presence of clusters, and Gram stain response help in identifying the bacterial species.
For example, spherical, gram-positive bacteria that form grape-like clusters are indicative of staphylococcal bacteria, which are often found in wound infections. Staphylococcus aureus is a common example of such bacteria, which can be identified through techniques such as passive agglutination testing or determining its susceptibility to coagulase.
Additional tests, such as antimicrobial susceptibility testing (AST), inform the healthcare providers about the efficacy of various antibiotics against the isolated bacteria. This is crucial in cases where bacteria may show resistance to commonly used antibiotics. For instance, if the bacteria are found to be resistant to several common antibiotics but susceptible to cefoxitin and oxacillin, the treatment plan can be adjusted accordingly, leading to the resolution of the infection.