Throat and Sputum Lab

This week in lab we looked at throat cultures, a quick throat screen, sputum culture and sputum gram stains. We were given three throat swabs along with media that had already been plated out. There were two isolates on the SBA. The first was beta hemolytic translucent, white and glistened. The second was small, white, opaque and convex. The presumptive ID on number one was a beta hemolytic Streptococcus because the catalase test was negative. A PYR test was also done and was negative. From this I determined that a PathoDx should be done and was "C" positive indicating Streptococcus dysgalactiae subsp. Equisimilis. Notice from the picture below this looks like group A strep, and the PYR and PathoDx are what differentiate them. Isolate 2 was determined to be normal flora and was a coagulase negative Staph. The throat screens were very simple to do, and one of mine was positive for group A Streptococcal antigen, indicating the patient should be treated. The other was negative, so a culture should be done.

Streptococcus dysgalactiae subsp. Equisimilis (group G strep) beta hemolysis

The sputum cultures also had 2 isolates. On SBA, number 1 was mucoid, gray, and opaque while number 2 was small white and opaque. Number 1 grew on SBA, MAC, and Chocolate meaning it was a negative rod and was a SLF. An oxidase test was done and was negative so an API 20E gave results of Klebsiella pneumonia. The other isolate was coagulase negative Staphlococcus. This finding of K. pneumoniae was consistant with the case given that the patient had a cough producing thick bloody phlegm ("currant jelly"). He also had lower lobe infiltrate and a pulmonary abscess.