CRYPTOCOCCUS NEOFORMANS

PATHOGEN SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Cryptococcus neoformans

SYNONYM OR CROSS REFERENCE: C. neoformans var neoformans, C. neoformans var gattii (also known as C. gattii), cryptococcosis, cryptococcal infections, cryptococci, torulosis, European blastomycosis ^{Footnote 1-Footnote 3} .

CHARACTERISTICS: C. neoformans is a spherical yeast, 4-6 µm in diameter, that produces a capsule containing glucoronoxylomannan (GXM), extending the overall diameter to 25 μm or more ^{Footnote 4-Footnote 6}. C. neoformans usually has a single bud that pinched off at the mature stage ^{Footnote 4} . C. neoformans may also exist in pseudohyphal form. It is subgrouped into serotypes based on a defined set of capsule-reactive immune sera: A, B, C, D, and the hybrid A/D ^{Footnote 2, Footnote 7}. C. neoformans var neoformans contains serotypes A and D, and C. neoformans var. gattii contains serotypes B and C ^{Footnote 1}. C. neoformans can differentiate into several complicated morphological forms, including yeast, chlamydospores, pseudohyphae and hyphae, and is typically present in the yeast form during infections. Small-sized basidiospores (1.8 to 3.0 μm) can turn into yeast cells, the form preferred at 37°C, or can form dikaryotic hyphae which are favoured at 24°C ^{Footnote 8}. This organism exists as a yeast form in the environment ^{Footnote 9}.

SECTION II - HAZARD IDENTIFICATION

PATHOGENICITY/TOXICITY: C. neoformans causes various diseases in immunocompromised and immunocompetent hosts ^{Footnote 10}. Diseases include meningoencephalitis (77.2%), pulmonary cryptococcosis (mostly in immunocompromised hosts, 8.2%), and several other diseases. Disseminated cryptococcosis is a complication and may occur in 91.8% of cases ^{Footnote 11}. Cryptococcosis may be fatal if untreated. Spores or desiccated yeast cells of C. neoformans enter the host respiratory tract by inhalation ^{Footnote 1, Footnote 2}. Serotypes A and D are opportunistic pathogens while serotypes B and C may infect immunocompetent individuals ^{Footnote 1, Footnote 12}. Pulmonary infection disseminates most commonly to the brain and the skin ^{Footnote 2}. C. neoformans can cause systemic infection, including fatal meningitis (meningoencephalitis) in normal, diabetic, and immunocompromised hosts ^{Footnote 13}. The infection from C. neoformans in the brain can be fatal if untreated ^{Footnote 8}.

CNS infection: Cryptococcosis of the CNS presents mostly in the form of acute, subacute, and chronic meningitis, with symptoms of persistent headache, nausea, dizziness, ataxia, impaired memory and judgment, irritability, somnolence, clumsiness, and confusion ^{Footnote 6, Footnote 10}. Patients may or may not have fever, and most have minimal or no nuchal rigidity. As the disease progresses, seizures may occur. CNS infection may also present as a brain abscess (cryptococcomas), subdural effusion, dementia, isolated cranial nerve lesion, spinal cord lesion, and ischaemic stroke. If cryptococal meningitis occurs, mortality rate is between 10-30% ^{Footnote 14}.

Respiratory infection: Pulmonary cryptococcosis may present as cough, dyspnea, blood-streaked sputum, and a dull ache in the chest ^{Footnote 6}. Other respiratory system infections include pneumonia, cavitation, endobronchial masses, empyema, nodules, sinusitis, mediastinitis, bronchiolitis obliterans, and pneumothorax ^{Footnote 10}.

Cutaneous infection: Skin lesions may be single or multiple and commonly begin as painless lesions of the face or scalp ^{Footnote 6}. Skin lesions may take the form of erythematous or umbilicated papules, pustules, acneiform lesions, indurated plaques, palpable purpura, soft subcutaneous masses, sinus tracts, cellulitis, vesicles, or large ulcers with undetermined edges.

Rarer presentations include lymphadenitis, pancreatitis, hepatitis, peritonitis, oesophagitis, osteomyelitis, septic arthritis, myositis, endophthalmitis, papilloedema, optic nerve atrophy, pyelonephritis, prostatitis, endocarditis, fungaemia, myocarditis, pericaditis, Cushing’s syndrome, adrenal insufficiency, adrenal mass lesions, and thyroiditis ^{Footnote 10} .

EPIDEMIOLOGY: There are differences in number of cases in different strains of C. neoformans ^{Footnote 1}. C. neoformans serotypes A and D are distributed worldwide and cause the vast majority of cryptococcal infections, predominately in immunocompromised individuals. Serotype A is responsible for over 95% of cryptococcosis cases worldwide ^{Footnote 1}. C. neoformans serotype A appears to be implicated in 99% of AIDS patients with cryptococcosis worldwide, except in France where serotype A is responsible for around 80% of the infections ^{Footnote 12}. More frequent cases of serotype A and D have been reported in Europe where cryptococcosis is associated with 77% of HIV patients. C. gattii strains B and C are localized in tropical and subtropical regions (e.g. Australia, Papua New Guinea, and South America) and cause cryptococcal infections mostly in immunocompetent hosts ^{Footnote 1}. C. gattii isolates can also cause infections in regions with a temperate climate. Cryptococcal meningitis, caused by the fungus C. neoformans, can cause up to 30% mortality in AIDS patients in resource-poor regions such as Southeast Asia ^{Footnote 1}. It is estimated that 6% to 10% of patients with AIDS in the United States, Western Europe, and Australia and 0% to 50% of AIDS patients in sub-Saharan Africa are infected with life-threatening cryptococcal meningitis ^{Footnote 12}. By the 1990s, C. neoformans had become the leading cause of culture-positive meningitis in many regions, including New York City. Cryptococcal meningitis alone kills about 624,000 people each year ^{Footnote 1}.

HOST RANGE: Humans and various domestic and wild animals (e.g., cats, birds) ^{Footnote 1, Footnote 7}.

INFECTIOUS DOSE: Unknown.

MODE OF TRANSMISSION: Spores are inhaled from the environment as the organism is found in the soil ^{Footnote 1, Footnote 15}.

INCUBATION PERIOD: Unknown, C. neoformans can colonize in the host respiratory tract for months to years without causing any clinical symptoms ^{Footnote 1}.

COMMUNICABILITY: Person-to-person transmission has not been documented other than through transplanted organs ^{Footnote 6}.

SECTION III - DISSEMINATION

RESERVOIR: C. neoformans may be found in humans and various domestic and wild animals ^{Footnote 1, Footnote 7}. Soil and decaying vegetation is also a reservoir for serotypes A and D ^{Footnote 1}, while serotypes B and C are found in trees. C. neoformans is associated with various environmental niches, especially avian guano ^{Footnote 1, Footnote 9}.

ZOONOSIS: Although C. neoformans may be encountered in animals, direct transmission from animals to persons has not been proven ^{Footnote 17}.

VECTOR: None.

SECTION IV: STABILITY AND VIABILITY

DRUG SUSCEPTIBILITY/RESISTANCE: Amphotericin B or itraconazole ^{Footnote 15} with or without flucytosine or flucanazole.

DRUG RESISTANCE: C. neoformans can develop resistance to fluocytosine when used alone ^{Footnote 5}.

SUCEPTIBILITY TO DISINFECTANTS: C. neoformans is effectively killed by 70% ethyl alcohol and is susceptible to phenolic compounds, formaldehyde, glutaraldehyde, iodophors, and sodium hypochloride (1%) ^{Footnote 18, Footnote 19}.

PHYSICAL INACTIVATION: Photodynamic therapy (PDT), which combines methylene blue (MB) with a low-power red laser can inactivate C. neoformans ^{Footnote 20}. PDT can be performed using 150 μM MB and 100mW red laser with a florescence at 180J/cm2 for 9 min. C. neoformans can be inactivated by UV, microwave, gamma radiation, moist heat (121°C for at least 20 min), and dry heat (165-170°C for 2 h) ^{Footnote 21-Footnote 24}.

SURVIVAL OUTSIDE HOST: Unknown; however, the main reservoir for C. neoformans is the environment, including the soil, bird guano, and trees ^{Footnote 1, Footnote 9}.

SECTION V – FIRST AID / MEDICAL

SURVEILLANCE: Monitor for symptoms and confirm by culture and histopathology and serologically. Nested PCR may be used ^{Footnote 4, Footnote 5, Footnote 15, Footnote 25}.

Note: All diagnostic methods are not necessarily available in all countries.

FIRST AID TREATMENT: Give appropriate antifungal therapy ^{Footnote 6}.

IMMUNIZATION: No immunization is currently available ^{Footnote 15}; however, some vaccines are currently in clinical trials, including GXM conjugated to tetanus toxoid vaccine, which has been shown to be effective in immunocompetent individuals in clinical trials ^{Footnote 12}.

PROPHYLAXIS: HIV patients may receive antifungal therapy such as fluconazole when no symptoms of infections are present ^{Footnote 9}.

SECTION VI - LABORATORY HAZARDS

LABORATORY ACQUIRED INFECTIONS: There is 1 reported case of laboratory exposure to C. neoformans from a laceration by a contaminated scalpel blade ^{Footnote 26}. There are 2 reported cases of eye infections related to surgical procedure from C. neoformans ^{Footnote 9}. Cryptococcosis from a needle puncture to the thumb during blood collection from an AIDS patient with cryptococcal fungemia and two percutaneous cryptococcal inoculations from needlestick have been reported.

SOURCES/SPECIMENS: C. neoformans may be found in soil, bird guano, blood, urine, and specimens from bone marrow, brain, CSF, eye, respiratory sites, skin, and mucous membranes ^{Footnote 1, Footnote 4, Footnote 26}.

PRIMARY HAZARD: Inhalation of basidiospores and desiccated yeast cells could be infectious for the lab workers and should be regarded as potentially serious airborne hazards ^{Footnote 9}. Accidental parenteral inoculation of infectious materials may also occur ^{Footnote 9, Footnote 26}.

SPECIAL HAZARD: Bites from infected lab mice and manipulation of infectious environmental materials (e.g. pigeon dropping) may be a potential hazard ^{Footnote 26}.

SECTION VII – EXPOSURE CONTROLS / PERSONAL PROTECTION

RISK GROUP CLASSIFICATION: Risk Group 2 ^{Footnote 27}.

CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures ^{Footnote 28}.

PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes ^{Footnote 28}.

OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities ^{Footnote 28}.

SECTION VIII – HANDLING AND STORAGE

SPILLS: Allow aerosols to settle. Wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at perimeter and working towards the centre; allow sufficient contact time before clean up.

DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing.

STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled.

SECTION IX – REGULATORY AND OTHER INFORMATION

REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: October 2010

PREPARED BY: Pathogen regulation directorate, Public Health Agency of Canada

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2010
Canada

REFERENCES:

Footnote 1

Lin, X. (2009). Cryptococcus neoformans: Morphogenesis, infection, and evolution. Infection, Genetics and Evolution, 9(4), 401-416.

Footnote 2

Doering, T. L. (2009). How sweet it is! Cell wall biogenesis and polysaccharide capsule formation in Cryptococcus neoformans. Annual Review of Microbiology, 63, 223-247.

Footnote 3

Chand, K., & Lall, K. S. (1976). Cryptococcosis (Torulosis, European blastomycosis) of the knee joint: a case report with review of the literature. Acta Orthopaedica, 47(4), 432-435.

Footnote 4

Shea, Y. R. (2007). Algorithms for Detection and Identification of Fungi. In P. R. Murray, E. J. Baron, J. H. Jorgensen, M. A. Pfaller & M. L. Landry (Eds.), Manual of Clinical Microbiology. (9th ed., pp. 1745-1761). Washington, USA: ASM press.

Footnote 5

Ryan, K. J. (2004). Cryptococcus, Histoplasma, Coccidioides, and Other Systemic Fungal Pathogens. In K. J. Ryan, & C. G. Ray (Eds.), Sherris Medical Microbiology: An introduction to infectious diseases (4th ed., pp. 669-684). New York, USA: McGraw-Hill.

Footnote 6

Dale, D. C., STAT!Ref, & Teton Data Systems. (2007). Infectious Diseases: The Clinician's Guide to Diagnosis, Treatment and Prevention (17th ed.). New York: WebMD Corporation. Retrieved from STAT!Ref

Footnote 7

Hazen, K. C., & Howell, S. A. (2007). Candida, Cryptococcus, and Other Yeasts of Medical Importance. In P. R. Murray, E. J. Baron, J. H. Jorgensen, M. A. Pfaller & M. L. Landry (Eds.), Manual of Clinical Microbiology. (9th ed., pp. 1762-1788). Washington, USA: ASM press.

Footnote 8

Karkowska-Kuleta, J., Rapala-Kozik, M., & Kozik, A. (2009). Fungi pathogenic to humans: Molecular bases of virulence of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. Acta Biochimica Polonica, 56(2), 211-224.

Footnote 9

Schell, W. A. (2006). Mycotic Agents of Human Disease. In D. O. Fleming, & D. L. Hunt (Eds.), Biological Safety: prinicples and practices (4th ed., pp. 163-178). Washington, DC: ASM press.

Footnote 10

Day, J. N. (2004). Cryptococcal meningitis. Practical Neurology, 4(5), 274.

Footnote 11

Rozenbaum, R., & Gonçalves, A. J. R. (1994). Clinical epidemiological study of 171 cases of cryptococcosis. Clinical Infectious Diseases, 18(3), 369-380.

Footnote 12

Schop, J. (2007). Protective immunity against cryptococcus neoformans infection. McGill Journal of Medicine, 10(1), 35-43.

Footnote 13

Baronetti, J. L., Chiapello, L. S., Aoki, M. P., Gea, S., & Masih, D. T. (2006). Heat killed cells of Cryptococcus neoformans var. grubii induces protective immunity in rats: Immunological and histopathological parameters. Medical Mycology, 44(6), 493-504.

Footnote 14

Bicanic, T., & Harrison, T. S. (2005). Cryptococcal meningitis. British Medical Bulletin, 72(1), 99.

Footnote 15

Human Diseases Caused by Fungi and Protozoa. (2005). In L. M. Prescott, J. P. Harley & D. A. Klein (Eds.), Microbiology (6th ed., pp. 917-936). New York, USA: Mcgraw Hill.

Footnote 16

Wilson, W. R., Sande, M. A., Drew, W. L., STAT!Ref, & Teton Data Systems. (2001). Current diagnosis & treatment in infectious diseases. New York: Lange Medical Books/McGraw-Hill. Retrieved from STAT!Ref

Footnote 17

Krauss, H., Weber, A., Appel, M., Enders, B., Isenberg, H. D., Sheifer, H. S., Slenczka, W., von Graevenitz, A., & Zahner, H. (2003). Fungal Zoonoses. Zoonoses: Infectious Diseases Transmissible from Animals to Humans (3rd ed., pp. 253-259). Washington D.C.: ASM Press.

Footnote 18

Centers for Disease Control and Prevention: Healthcare Infection Control Practices Advisory Committee. (2009). Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Retrieved 04/01, 2010, from Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008

Footnote 19

Collins, C. H., & Kennedy, D. A. (1999). Laboratory acquired infections. Laboratory acquired infections: History, incidence, causes and prevention (4th ed., pp. 1-37). Woburn, MA: BH.

Footnote 20

Prates, R. A., Da Silva, E. G., Chaves, P. F., Santos, A. J. S., Paula, C. R., & Ribeiro, M. S. (2009). Photodynamic therapy can kill Cryptococcus neoformans in in vitro and in vivo models. Paper presented at the , 7165

Footnote 21

Katara, G., Hemvani, N., Chitnis, S., Chitnis, V., & Chitnis, D. S. (2008). Surface disinfection by exposure to germicidal UV light. Indian Journal of Medical Microbiology, 26(3), 241-242.

Footnote 22

Wu, Y., & Yao, M.Inactivation of bacteria and fungus aerosols using microwave irradiation. Journal of Aerosol Science, In Press, Corrected Proof doi:DOI: 10.1016/j.jaerosci.2010.04.004

Footnote 23

Farkas, J. (1998). Irradiation as a method for decontaminating food. A review. International Journal of Food Microbiology, 44(3), 189-204.

Footnote 24

Csucos, M., & Csucos, C. (1999). Microbiological obseration of water and wastewater. United States: CRC Press.

Footnote 25

Clinical Microbiology. (2005). In L. M. Prescott, J. P. Harley & D. A. Klein (Eds.), Microbiology (6th ed., pp. 799-819). New York, USA: Mcgraw Hill.

Footnote 26

Biosafety in Microbiological and Biomedical Laboratories. (1995). In D. O. Fleming, J. H. Richardson, J. J. Tulis & D. Vesley (Eds.), Laboratory Safety Principles and Practices (2nd ed., pp. 293-354). Washington, DC, USA.: ASM press,.

Footnote 27

Human Pathogens and Toxins Act. S.C. 2009, c. 24. Government of Canada, Second Session, Fortieth Parliament, 57-58 Elizabeth II, 2009, (2009).

Footnote 28

Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), Laboratory Biosafety Guidelines (3rd ed.). Canada: Public Health Agency of Canada.