Guidelines and Handbook for IBSCs - Department of Biotechnology

Check List for IBSCscategorized with four groups based on the infectivity potential (pathogenicity)for humans out of which the first group is that of non-pathogens (Table 3).This categorization is generally applicable only for the assessment of containmentrequirements as greater containment is required to control the organismin the higher hazard groups to ensure that the organism does not infect thoseworking with it.Table 3: Categorization of microorganisms based on pathogenicityHazard Group 1Hazard Group 2Hazard Group 3Hazard Group 4Organisms that are most unlikely to cause human diseaseOrganisms capable of causing human disease and which may be ahazard to laboratory workers, but are unlikely to spread to theother co-workers of sister laboratories or community. Laboratoryexposure rarely produces obvious infection or severe diseasesymptoms and effective prophylaxis or effective treatment isusually availableOrganisms that cause severe human disease and present a serioushazard to laboratory workers. They may present a risk of spreadto the community, but there is usually effective prophylaxis ortreatment availableOrganisms that cause severe human disease and are a serioushazard to laboratory workers. They may present a high risk ofspread to the community, and there is usually no effectiveprophylaxis or treatment except quarantine measures.The details of microorganisms falling into each category are given in theRecombinant DNA Safety Guidelines, 1990.Some organisms have been frequently used in rDNA technology experimentsand their characteristics have been described in detail e.g. E. coli or Saccharomycescerevisae, about which a great deal is known. Further, no pathogenic strains ofbakers' or brewers' yeast have ever been observed. This type of familiarity allowssome confidence in attempting to identify risks associated with their modification.Some strains, for example, E. coli K12 has been disabled to remove some of thefactors that might be associated with pathogenicity (wild type E. coli is a HazardGroup 2 pathogen). The factors which have been lost include the cell-surface KGuidelines and Handbook for Institutional Biosafety Committees (IBSCs) 27