Closing the Brief Case: Dyspnea in a Profoundly Immunocompromised Man

ANSWERS TO SELF-ASSESSMENT QUESTIONS

1. Paecilomyces species may display various pigmentation; however, isolates never appear:

   • (a)
     Yellow-tan
   • (b)
     Yellow-green
   • (c)
     Blue-green
   • (d)
     Pink-mauve

Answer: c. The surface color of Paecilomyces species recovered in culture can be variable; however, the color is never blue-green, as seen with Penicillium species.

1. Paecilomyces species have not been associated with which of the following infection(s):

   • (a)
     Endocarditis
   • (b)
     Catheter-related fungemia
   • (c)
     Skin infections
   • (d)
     Cholangitis

Answer: d. Paecilomyces species have been associated with endocarditis, catheter-related fungemia, and skin infections but not cholangitis. The genus has also been reported to cause nephritis, pulmonary infections, ocular infections, and subcutaneous infections.

1. Which antifungal is emerging as the most effective treatment for Paecilomyces species?

   • (a)
     Amphotericin B
   • (b)
     Posaconazole
   • (c)
     Voriconazole
   • (d)
     Flucytosine

Answer: b. Although in vitro susceptibility results have yet to be correlated with in vivo responses, posaconazole is the only antifungal to show good in vitro activity against all of the species tested. Because of the lack of correlation between in vitro results and in vivo responses, the clinical utility of susceptibility testing is uncertain.

TAKE-HOME POINTS

• Paecilomyces species are frequently considered contaminants when recovered in culture, but because of the growing number of immunocompromised patients, the genus is increasingly associated with disease.

• Paecilomyces species have been associated with endocarditis, nephritis, pulmonary infections, and catheter-related fungemia, as well as nail, ocular, cutaneous, and subcutaneous infections.

• Although Paecilomyces and Penicillium species have similar microscopic morphologies, the surface color of Paecilomyces species is never blue-green, as seen with Penicillium species.

• Paecilomyces species are difficult to identify to the species level on the basis of morphological features alone, and thus, molecular methods are more commonly being used to provide identification to the species level.

• The in vitro antifungal susceptibility pattern of Paecilomyces species varies by species, but the lack of correlation between in vitro results and in vivo responses, the clinical utility of susceptibility testing is uncertain.

(See page 2410 in this issue [doi:10.1128/JCM.00049-16] for case presentation and discussion.)