A patient is infected with a bacteria that is resistant to erythromycin (the antibiotic is not effective) and sensitive to clindamycin (the antibiotic is effective). However, the patient is not improving and the organism now appears to be resistant to both antibiotics. The reason for this alteration in gene expression in the bacterium is likely due to:
a. genetic regulation that encodes the resis-tance mechanism is constitutive.
b. the genetic regulation encoding the en-hanced resistance is inducible.
c. the genetic regulation for the enhanced resistance is normally suppressed.
d. the organism was always resistant to both antibiotics and should not have been treated with the combination therapy.
B
The genetic resistance is considered inducible. The clindamycin resistance is turned on only in the presence of the antibiotic erythromycin and is only active when an organism is resistant to that antibiotic. If the organism was susceptible to erythromycin, the organism would be killed and not alive to activate the resistance mechanism for the second antimicrobial agent.
You might also like to view...
During which of the following processes does the cytoplasm of two fungal hyphal cells fuse to form a dikaryotic (n+n) cell?
A. karyogamy B. heterokaryogamy C. plasmodesmatogamy D. plasmogamy
Large, uniform distances typically separate individual panda bears from each other. What type of population distribution do pandas exhibit?
A. random distribution B. logistic distribution C. clustered distribution D. over-dispersed distribution E. sinusoidal distribution
Which of the following relationships is INCORRECT?
A. Maternal effect genes activate gap genes. B. Gap genes activate pair-rule genes. C. Pair-rule genes activate segment polarity genes. D. These relationships are all correct. E. Segment polarity genes activate pair-rule genes.
The lack of blood flow to an organ, as in the case of a blood clot blocking an artery, is termed ____
What will be an ideal response?