A single positive bottle out of four, with a delayed flag t…
A single positive bottle out of four, with a delayed flag time and clusters on Gram stain, initially raisessuspicion for skin flora contamination (e.g., coagulase-negative staph). Blood cultures remain unflagged after the standard 5-day monitoring period; the lab extends incubation basedon the travel/exposure history noted on the requisition. On extended incubation, a bottle eventually flags positive. Gram stain shows tiny gram-negative coccobacilli. Given the exposure history and slow growth, what organism should be strongly suspected? What safety precaution iscritical at this point?
Read DetailsA 34-year-old with a history of IV drug use presents with fe…
A 34-year-old with a history of IV drug use presents with fever, chills, and a new heart murmur. Two sets of bloodcultures are drawn from separate peripheral sites. Both bottles (aerobic, both sets) flag positive within 12 hours. Gram stain: gram-positive cocci in clusters. Question 1: What organism(s) are possible? Is this more consistent with a true pathogen or contamination so far?
Read DetailsA 70-year-old with a prosthetic aortic valve (placed 8 month…
A 70-year-old with a prosthetic aortic valve (placed 8 months ago) presents with low-grade fever. Two sets ofblood cultures (four bottles total) are drawn from separate peripheral sites. Only 1 of the 4 bottles flags positive, after 4 days of incubation. Gram stain: gram-positive cocci in clusters Catalase: positive. Coagulase: negative. What organism group does this identify? Does a coagulase-negative result rule out true infection here — why or whynot?
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