A D-test is set up on a S. aureus isolate. There was no zone around the Erythromycin disk and the zone of inhibition around the clindamycin disk adjacent to the erythromycin disk was inter-preted as susceptible. Thus, the resistance mechanism for the erythromycin is due to:
a. altered target.
b. increased efflux.
c. decreased porin channels.
d. degradative enzymes.
B
This describes a negative D zone test. Thus, the erythromycin-R is due to msrA gene, which re-sults in increased efflux of erythromycin from the bacterial cell and does not induce clindamycin (macrolide-lincosamide-streptogramin B) resistance mediated by products of the erm genes (i.e., erthryomycin ribosomal methylase) which alters the MLS antibiotic target.
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Twelve PGAL molecules form when six CO2 are attached to six RuBP molecules. Two of these PGAL molecules are needed to form a 6-carbon sugar. What is the fate of the ten remaining PGAL molecules?
a. They are degraded. b. They are converted back to carbon dioxide. c. They are stored as extra PGAL molecules. d. They are used during photorespiration. e. They are converted to RuBP molecules.
Genetically modified organisms include ________.
A. plants B. bacteria C. nonhuman animals D. viruses E. All of the above have been genetically modified.
Successful bacterial resistance requires interruption of one or more of the stages essential for antimicrobial action. Which of the following is NOT a mechanism of bacterial resistance?
A) Environmental factorS B) Clinical threshold tested (antibiotic strength used in testing C) CAMP positivitY D) Biological characteristics
Streptococcus pyogenes commonly causes streptococcal toxic shock syndrome in otherwise healthy people
Indicate whether the statement is true or false