An outbreak of severe diarrhea occurs in an intensive care wing of a major hospital. As a result, the patients are all screened for colonization and infection by the pathogenic organism. However, not all of the patients identified carrying the organism by phenotypic identification and characte-rization are displaying symptoms of infection. The reason for this discrepancy is:
a. some patients have a stronger immunity to the pathogenic organism.
b. the patients who are not displaying symp-toms have been on antibiotics and the or-ganism has mutated and is no longer pa-thogenic.
c. the patients are not all infected with the same strain of the organism that is carrying the enteric toxin causing the diarrhea.
d. the laboratory has likely misidentified the organisms.
C
Many virulence genes are harbored on plasmids or transposons and may be transferred to other bacteria within the same or different genera and species. This transfer can result in recombination resulting in some strains of the same species of organism containing different physiologic characteristics including the existence of virulence factors such as exotoxins.
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