Final answer:
RFLP analysis uses restriction enzyme digestion and agarose gel electrophoresis to visualize DNA banding patterns that distinguish unique strains. API tests distinguish microbes based on biochemical test profiles, while 16S rRNA sequencing is less effective at strain differentiation due to sequence conservation. Additional methods like rep-PCR and susceptibility tests are used for finer strain discrimination and antibiotic resistance determination.
Step-by-step explanation:
Restriction Fragment Length Polymorphism (RFLP) analysis is a technique that can determine how many unique strains are represented among a number of isolates. This method utilizes the principle that each strain has a unique DNA sequence, leading to differences in the distribution of restriction-enzyme recognition sites. After restriction enzyme digestion, the DNA fragments are separated using agarose gel electrophoresis, resulting in distinct banding patterns that can be visualized on a gel. These banding patterns are like a genetic fingerprint, useful for comparing different DNA samples and determining the uniqueness of strains.
An API test is another method used to distinguish between microbial samples. It performs 10 to 20 different biochemical tests and produces a metabolic profile by detecting the presence of metabolic end products, colored due to pH indicators. Microbiologists can then compare the sample's metabolic profile to a database to identify the specific microbe.
While 16S rRNA sequencing is a reliable method for identifying bacterial species, it is not as effective for distinguishing between strains of the same species, like different E. coli strains. This is because the 16S rRNA gene is highly conserved among closely related strains, making it difficult to distinguish subtle genetic variations between them. Other methods such as rep-PCR and PCR ribotyping, which use more variable regions of the genome, can be used to distinguish strains with greater resolution.