Gram – Joint fluid: gram positive bacilli (Clostridium) and neutrophils – Shipped August 2014


A simulated joint fluid smear collected from an 18 year old male patient with an injury caused by a motorcycle accident was sent to category A, B, C, and C1 laboratories for Gram staining.

Participants were expected to report the presence of neutrophils and gram positive bacilli.


  1. Traumatic injury can result in introduction of soil organisms including Clostridium species into wounds. Infections and related tissue damage result from the combination of injury and microbial virulence features, including exotoxins.
  2. It is common to see substantial PMN damage in the presence of infection with Clostridium species. Noting the presence of severe cellular damage was not considered as a requirement to receive full marks (4) for the reading and interpretation of this slide.


Full critique (PDF)

Posted in Clinical Bacteriology Results, critiques, Gram