[Histonet] Re: possible AFB contaminant

[Robert Richmond]

Contaminant acid-fast bacilli (AFB) on tissue section slides can
usually be identified as such, because they're outside of the plane of
the tissue section.

The organism is a nearly non-pathogenic AFB called Mycobacterium
gordoneae or Mycobacterium aquae.

The problem affects both fluorescent and the old (and obsolete) light
microscopic techniques.

This problem underlines the importance of histotechnologists' knowing
how to interpret special stain control slides. I don't recall ever
having seen a publication directed at histotechnologists that clearly
explained how to identify acid-fast bacilli in tissue sections.

Bob Richmond
Samurai Pathologist
Knoxville TN