The two initial cases, reported in the June 28 issue of EPI Update, were diagnosed by a laboratorian at SHL who identified possible Cyclospora oocysts on microscopic examination of fresh stool and confirmed this diagnosis using a modified acid-fast stain
A modified acid-fast stain
is performed to identify parasites such as Cryptosporidium and Isospora, causing chronic diarrhoea in immunocompromised patients.
Gram stain (Figure, C) and a modified acid-fast stain
(Figure, D) revealed gram-positive, partially acid-fast filamentous organisms branching at right angles within the eosinophilic material consistent with Nocardia organisms.
The bug was considered a rare and exotic pathogen until the mid-1980s when a modified acid-fast stain
was employed to look for Cryptosporidium in stool specimens, especially from people with impaired immune systems who suffered from HIV disease. A much larger organism was frequently associated with enteritis and was variously described in subsequent reports as a large Cryptosporidium, a fungal spore, a member of the Blastocystis species, a cyanobacterium-like body (CLB, or blue-green algae), and coccidian-like.[6-9] These organisms probably were Cyclospora and have become associated with travel or residence in developing countries.
They were stained with Kinyoun's carbol fuchsin modified acid-fast stain
and examined by oil immersion microscopy.
All state laboratories began routine testing with a modified acid-fast stain
However, with the modified acid-fast stain
, CLB may stain deep mottled red or pink; some resist staining and appear as glassy, membranous cysts.
Use of modified acid-fast stains
, such as Kinyoun stain, also improves visualization .
CDC recommends reconfirmation of positive test results (by using direct fluorescent antibody testing or modified acid-fast stained
smears) obtained with ImmunoCard STAT![R] rapid assays from all recalled lots.