Final answer:
Two microbes can be determined to be closely related with MLST by sequencing specific housekeeping genes, creating a genetic profile based on the unique sequences within these genes.
Step-by-step explanation:
With MLST (Multilocus Sequence Typing), you can tell if two microbes are closely related by C) sequencing specific housekeeping genes. MLST is a precise method of characterizing bacteria based on the sequences of internal fragments of multiple (usually seven) housekeeping genes. Each unique sequence within a housekeeping gene is assigned an allele number, and the alleles at each of the gene loci provide an allelic profile or sequence type. This method allows for accurate identification, epidemiological studies, and can help infer phylogenetic relationships.
Analyzing an organism's antibiotic resistance or metabolic pathways, and observing cell morphology may provide useful information for identification but are not the primary focus of MLST. Antibiotic resistance, such as the MCR-1 gene that confers colistin resistance, can indicate the potential horizontal gene transfer between strains but does not determine genetic similarity as effectively as MLST. To identify microbes by metabolic capabilities, one would analyze the nutritional and metabolic capabilities of the bacterial isolate, but this approach is more biochemical than the genetic focus of MLST.