One of the foremen at a pig farm notices purple sores on one of his workers. The worker has not been feeling well for the past 2 weeks, so the foreman sends him to the physician. The physician takes scrapings from the lesions and sends them to the laboratory for a culture. The Gram stain shows 3+ thin, gram-positive rods that have filaments. The culture plates were examined the next day and revealed nonhemolytic, pinpoint, transparent colonies. What is the most likely pathogen?

Question

Quizplus · Accepted Answer

The presence of thin, gram-positive rods with filaments is characteristic of Erysipelothrix rhusiopathiae, which can cause purple sores and flu-like symptoms in humans who work with or handle infected animals, such as pigs. The nonhemolytic, pinpoint, transparent colonies on the culture plates are also consistent with this pathogen. Streptococcus pneumoniae and Streptococcus pyogenes are gram-positive cocci, not rods, and are not associated with purple sores or pig farming. Rhodococcus is a gram-positive, pleomorphic, aerobic rod that is not typically associated with human infections or pig farming.

One of the Foremen at a Pig Farm Notices Purple