Cryptococcus Neoformans | Legionella Pneumophila | Giardia and Cryptosporidium

ISOLATION OF CRYPTOCOCCUS NEOFORMANS

Cryptococcus neoformans is the infectious agent of the fungal disease cryptococcoses. Formerly a rare disease, the incidence of cryptococcoses has increased in recent years. This microorganism is commonly associated with old pigeon manure, but it has also been recovered from dried excreta of chickens, sparrows, starlings, and other birds.

C. neoformans uses the creatinine in avian feces as a nitrogen source. It gains a competitive advantage over other microorganisms and multiplies exceedingly well in dry bird manure accumulated in places that are not in direct sunlight.

ISOLATION PROCEDURE

The laboratory uses a dilution technique outlined by the Center for Disease Control and Prevention. The samples go through several dilutions with each dilution plated on specialized media for the isolation of Cryptococcus neoformans. Our laboratory has 18 years of experience in the isolation of this organism. Results can be expected within 4-5 days. Reports of these results can be expected within two weeks from receipt of samples.

MORE INFORMATION

More information about this fungus can be received by contacting our laboratory or from the Center for Disease Control and Prevention website. TOP

LEGIONELLA PNEUMOPHILA IN CONTAMINATED WATER

Legionella pneumophila is a bacteria which causes the disease legionellosis. L. pneumophila was first identified in 1977 by the CDC as the cause of an outbreak of pneumonia that caused 34 deaths at a 1976 American Legion Convention. In the U.S., Legionnaire's disease is considered to be fairly common and serious, and the Legionella organism is one of the top three causes of sporadic, community-acquired pneumonia.

TRANSMISSION

The likelihood of contracting Legionnaires' disease is related to the level of contamination in the water source, the susceptibility of the person exposed, and the intensity of exposure to the contaminated water. Disease transmission usually occurs via inhalation of an aerosol of water contaminated with the organism.

COMMON SOURCES OF CONTAMINATED WATER

Water sources that frequently provide optimal conditions for growth of the organisms include:

• cooling towers
• domestichot-water systems that operate below 60 degrees C
• humidifiers
• spas and whirlpools
• dental water lines at a temperature above 20 degrees C
• other water sources including stagnant water in fire sprinkler systems

ISOLATION OF LEGIONELLA

Analysis of water samples from a source suspected of being contaminated with L. pneumophila is a valuable means of identifying potential sources of the disease. Our microbiological laboratory has 16 years of experience in the detection of Legionella and can determine the number of organisms present in colony forming units per milliliter of water and can determine the identity of serogroups of Legionella pneumophila in the sample.

CULTURED SAMPLES

Water samples are cultured on special buffered charcoal yeast extract culture media. Selective isolation processes to eliminate other microbial overgrowth can determine the number of CFU of L. pneumophila per milliliter of water. This process of growth and isolation is time-consuming, and results typically require 7-14 days from the time of submission.

ADDITIONAL INFORMATION

For additional information about Legionella isolation and identification please call our laboratory or access the Center for Disease Control website. TOP

GIARDIA AND CRYPTOSPORIDIUM IN WATER

Giardia lamblia are flagellated protozoans first documented in 1966 as causative agents of waterborne intestinal disease in the United States. Since that time, numerous outbreaks of giardiasis have occurred throughout the United States, principally in mountainous areas. Giardia are currently the predominant cause of waterborne illness, accounting for more than 50 percent of the identified cases. Giardia form environmentally resistant cysts that allow for the extended survival of the parasite in surface and treated drinking water. This organism has previously been reported to be present in lakes, rivers, and creeks with a survival rate of at least 16 days. Cryptosporidium are protozoans first described in 1907 but only recognized as an agent of human waterborne diseases in 1987. Like Giardia, Cryptosporidium form environmentally resistant oocysts. Cryptosporidium appear to be widely distributed in the aquatic environment and resist the normal water treatment processes due to their size and increased disinfection resistance.

ISOLATION METHOD

Samples (10 liters) are sent to the laboratory where a filtration process is completed. The filter is processed using the USEPA Method 1622 for the Isolation of Cryptosporidium and Giardia in water samples. The entire procedure usually takes 1 -1½ days to complete. Our laboratory has 6 years of experience isolating these two protozoans from water samples. You may expect results within one week from the date of receipt.

ADDITIONAL INFORMATION

For additional information about the isolation of these two protozoans, please contact our laboratory or access the USEPA website. TOP