A Weil-Felix test was performed on serial dilutions from a patient bitten by a tick. The results ...

A
Patients with R. prowazekii (epidemic typhus), R. typhi (murine typhus), and R. rickettsii (Rocky Mountain spotted fever) will be positive for OX-19 and negative for OX-2 and OX-K. However, R. prowazekii is transmitted via lice, and R. typhi is transmitted via fleas. R. rickettsii is trans-mitted via ticks. O. tsutsugamushi (scrub typhus) will be positive for OX-K and negative for OX-19 and OX-2 and is transmitted by chiggers.

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B
Because indigenous anaerobes are often present in large numbers as normal flora on mucosal surfaces, even minimal contamination of a specimen can give misleading results. Specimens that are likely to be contaminated are unacceptable for anaerobic culture. Cervical specimens that pass through the lower genital tract will likely be contaminated with genital flora.

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C
Species of mycobacteria synthesize carotenoids (i.e., a group of pigments that are yellow to red) in varying amounts and are categorized into three groups based on the production of these pig-mentsnonphotochromogens, photochromogens, and scotochromogens. The nonphotochromo-gens are slow-growing NTM whose colonies produce no pigment whether they are grown in the dark or the light. The photochromogens are slow-growing NTM whose colonies become pig-mented when exposed to light. The scotochromogens are slow-growing NTM whose colonies are pigmented when grown in the dark or the light.

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D
The peripheral chromatin of the intestinal protozoan (amoeba), E. histolytica, contains fine gra-nules that are uniform in size and are evenly distributed. It also possesses progressive fingerlike pseudopodia and rapid motility.

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C
Streptomycin is the drug of choice for Y. pestis infections.

Confirmed correct!