In: Biology
Even though Gram stain is not very specific, studies have found that it is as accurate as DNA-based methods for identifying the causative pathogen of most urinary tract infections. Why do you think this is the case?
Answer: Gram staining is very fast and easy method to detect different types of bacteria as Gram positive and Gram negative. If we concern to UTI(urinary tract infections) the causative agent here is bacteria most probably Gram positive bacteria.
UTI is generally caused by Gram Negative (aerobic bacteria) while the case of Gram-positive bacteria is very less.
The vast majority of UTI is caused by a single species(only one organism) and rarely we see two or more type of bacteria that might be present. So when we culture the urine of UTI patient and see different type of organism so it is clear that the patient do not performed the Clean Catch method for sample collection.In Gram staining process we use the differential staining procedure to identify the Gram positive and Gram negative bacteria based on its colour they take after staining.
As in case of DNA-based methods for identifying the causative pathogen the causative agent must have a specific banding pattern which is normally not seen but only can be observed in specific or altered(mutated) or in pathogenic stage. Like that as the UTI patient when stained with Gram stain procedure thy will show only one type of apperance( as infected by only one type of organism) so presence of similar type of structure while staining with Gram stain is simple and specific method as DNA-based methods.