The recent Cryptococcus gattii outbreak
A deadly pathway… From Trees to Lungs to Brain
ryptococcus gattii disease. The route of C has been in the infection is from breathing the news lately, due to a recent airborne organism, which outbreak in the Pacific becomes lodged in the Northwest. This new, more pulmonary tissues. virulent strain is expected to by Jay Hardy, CLS, SM (NRCM) spread further throughout the Symptoms
Northwest and Northern California in the coming The pulmonary disease, Jay Hardy is the founder and months. known as cpryptococcosis, president of Hardy Diagnostics. develops slowly. After He began his career in exposure it can take two to microbiology as a Medical Technologist in Santa Barbara, twelve months for symptoms California. to appear, with the usual onset
In 1980, he began at six or seven months. manufacturing culture media for the local hospitals. Today, The symptoms include: Hardy Diagnostics is the third largest media manufacturer in the U.S. • Cough that lasts weeks or months To ensure rapid and reliable turn around time, Hardy • Sharp chest pain Figure 1: An India ink stain Diagnostics maintains six • Unexplained shortness of showing the capsule surrounding distribution centers, and breath produces over 3,000 products the C. gattii cells in the yeast form used in clinical and industrial at 1,000X. Photo from Haley/CDC. • Severe headache microbiology laboratories • Confusion throughout the world. The organism is a fungus that • Fever
is usually found in the soil • Night sweats www.HardyDiagnostics.com and on trees. It is not spread • Unintended weight loss from human to human or
animal to human. However, Those that are most some animals and pets have susceptible are those with a been known to contract this weakened immune system, although healthy individuals This new strain, dubbed way to protect against the have been known to be VGIIc, has been implicated in spread of this organism. infected as well, as seen in the the recent outbreak in Oregon. recent outbreak. Another strain of the same History pathogen, dubbed subtype More serious infections VGIIa, was responsible for 19 C. gattii is a close relative of develop into meningitis and deaths in Canada back in Cryptococcus neoformans, cerebral cryptococcomas. 1999. At that time, 218 people which is often implicated in were infected on Vancouver HIV/AIDS patients due to Island, in British Columbia; their impaired immunity. C. nine percent of these cases gattii is more likely to strike were fatal. Researchers say healthy individuals than is C. that the new form is very neoformans. It is also more similar to the old one; likely to progress from the however, the new strain is lungs to the brain (meningitis) killing one of every four than C. neoformans. victims.
It's puzzling that the North An electron microscope view of the American strains of this fungus from Duke University. fungus are so virulent, given that C. gattii has existed in The Geography of Infection South America, Africa and Australia for many years Infections have been found in where it is commonplace, but Washington, Oregon, British much less dangerous. Columbia, and perhaps Figure 2: Colonies of Cryptococcus Northern California. will turn brown on Caffeic Acid Just how virulent is this new Agar also known as Bird Seed strain? A recent study by Agar. Most of the original cases Edmund Byrne at Duke were found on the East side of University found that the The infection was once Vancouver Island in British Oregon strain of considered endemic, Columbia, Canada beginning Cryptococcus gattii killed 25 occurring sporadically in the in 1999. percent of the people it tropics and subtropics where infected, but the overall the fungus was known to The New Strain numbers of people infected grow on the eucalyptus trees. were small. In lab animals, the In 1999, the range of this A more virulent stain has disease was found to be 100% pathogen expanded to claimed six lives in Oregon fatal, which is not the case Vancouver Island, British and a total of 21 have become with previous strains. Columbia, Canada. Since infected recently. Particularly 2004, over 50 cases of C. worrisome is that the new The public has been cautioned gattii infection have been strain can strike otherwise against becoming panicked, documented in the Pacific healthy individuals and has while being reminded of the Northwest of the United been known to progress into extreme rarity of this disease. States. The source is usually CNS tissue. Even so, there is currently no traced back to trees. Over 50
species of trees have been found as a source of C. gattii spores.
During a recent study on Vancouver Island in Canada, the organism was isolated in high traffic areas in automobile wheels and Figure 4: A rapid caffeic acid disk footwear. Another common can be used to identify Cryptococcus within four hours. location was in woodchips Figure 6: C. gattii turning the used for landscaping. An India ink prep is useful in media blue on a CGB Agar plate within five days. This media will detecting the polysaccharide Recently, there have been distinguish C. gattii from C. capsule surrounding the several reports of a more neoformans. irregularly sized yeast cells. deadly strain that is a hybrid
of C. neoformans and C. gattii All strains of C. neoformans found in Europe and Canada. are not capable of producing this color change.
Treatment
Once correctly diagnosed, C. gattii is treated with the anti- fungals, amphotericin B and fluconazole. Treatment is Figure 5: Colonies showing prolonged (3 to 12 months) reddish brown pigment production and is oftentimes less
on Caffeic Acid Agar (Bird Seed effective than with C. Figure 3: A three day old culture of Agar). neoformans infections. Cryptococcus on a Caffeic Acid Agar Slant. One way to distinguish C.
neoformans from C. gattii is Now that we are over the with the use of CGB Agar. Identification H1N1 Influenza pandemic, This highly selective medium we are once again challenged utilizes the ability of C. gattii Cryptococcus spp. are easily with a new outbreak to keep to create an alkaline shift in cultured on typical fungal our eyes on in the coming pH when creatine is degraded media. Caffeic Acid Agar will months. As a somewhat to ammonia. This causes the cause the colonies to turn “new” organism, further study media to turn from yellow- brown. Another more rapid of C. gattii is definitely green to cobalt blue. method involves the use of a warranted.
paper disk containing caffeic acid. Jay Hardy, CLS, SM (NRCM) Santa Maria, CA