A clinical microbiology laboratory is monitoring the emergence of resistance to colistin in Gram-negative bacteria. Resistance to colistin is often mediated by modifications of the bacterial lipopolysaccharide (LPS).
The genetic basis for acquired colistin resistance most commonly involves:

A patient with a history of travel to Southeast Asia presents with fever, severe headache, and altered mental status. CSF analysis reveals lymphocytic pleocytosis and elevated protein, but routine bacterial and viral cultures are negative. Serological testing of CSF is positive for IgM antibodies against Japanese encephalitis virus. The MOST likely mode of transmission for this infection is:

A clinical microbiology laboratory isolates a Gram-negative rod from a wound infection following a dog bite.
The organism grows on MacConkey agar, is oxidase-positive, and produces a characteristic bleach-like odor.
The MOST likely identification is:

Caspofungin, micafungin, and anidulafungin belong to the echinocandin class of antifungal agents. Their primary mechanism of action involves the non-competitive inhibition of:

A research team is investigating the mechanism of bacterial resistance to a novel fluoroquinolone antibiotic.
They isolate a resistant strain of Escherichia coli from a patient with a urinary tract infection. Genetic analysis of this strain reveals a point mutation in the gyrA gene. This mutation MOST likely results in: