Summary of Changes to the Biosafety in Microbiological and Biomedical Laboratories 6th Edition (BMBL-6)

This Summary of Changes was prepared by the ABSA International Technical and Regulatory Review Committee (TRR). May 2021

This Summary of Changes is not to be used as a substitute for the CDC/NIH BMBL-6 edition.

Table of Contents

I: Introduction

II: Biological Risk Assessment

III: Principles of Biosafety

IV: Laboratory Biosafety Criteria
   Biosafety Level 1 (BSL-1)
   Biosafety Level 2 (BSL-2)
   Biosafety Level 3 (BSL-3)
   Biosafety Level 4 (BSL-4)


V: Vertebrate Animal Biosafety Level Criteria for Vivarium Research Facilities
   Animal Biosafety Level 1
   Animal Biosafety Level 2
   Animal Biosafety Level 3
   Animal Biosafety Level 4

VI: Principles of Laboratory Biosecurity

VII: Occupational Health Support for Biomedical Research


Section VIII-A: Bacterial Agents (pages 148-191)

The introduction specifically notes that there are multiple resources for agent information and that the BMBL-6 is just one of those that is used by the Biosafety Professional.

The BMBL-6 updated the information related to mortality rates caused by anthrax. New information was added regarding pathogenicity of Anthrax from known exposures based on the route of exposure and post-exposure treatment. The Special Issues section includes advice on possible misidentification using automated systems such as MALDI-TOF MS. The Vaccines section includes multiple revisions on the criteria for vaccination of workers depending on the job activity. This section also includes new available treatments. Lastly, the Bacillus cereus biovar anthracis was included as a Select Agent.
The BMBL-6 updated the general information about Bordetella pertussis by including the option to be diagnosed via molecular methodologies. The natural modes of infection were updated to reflect the recent global increase of cases and circulation of B. pertussis in vaccinated communities. Of note, the BMBL-6 included direct contact as a hazard with additional details on survival of the bacteria on surfaces. It also updated the availability of pertussis vaccines to adults.
The major update to this microbe was reflected in the classification of 10 species divided into terrestrial, marine, or unknown origin. B. maris was removed from the list but added B. delphini, B. pinnipedialis, and B. ceti The occupational infections attributed to Brucella sp were updated to include LAIs due to mishandling and misclassification of the bacteria. The Special Issues section includes advice on possible misidentification using automated systems such as MALDI-TOF MS. The Vaccines section was updated to reflect current potential vaccines against Brucella.
The former name (Pseudomonas mallei) was removed in the BMBL-6 and added general information related to mortality rates. The natural modes of infection were expanded to include pulmonary infection, bacteremia, etc. Laboratory safety information about survival of B. mallei up to 30 days in water at room temperature was added. The reference to procedures conducted outside the BSC using respiratory protection was removed in the BMBL-6. The Special Issues section includes advice on possible misidentification using automated systems such as MALDI-TOF MS.
The former name (Pseudomonas pseudomallei) was removed in the BMBL-6. Multiple updates were included to this section related to current epidemiological numbers, occupational infections. A significant update pertains to the laboratory safety and containment recommendations shifting most handling of contaminated samples to BSL-3 containment; while BSL-2 is recommended for inoculation of cultures from potentially infectious clinical samples. The Special Issues section includes advice on possible misidentification using automated systems such as MALDI-TOF MS.
The general information was updated to indicate that Campylobacters species are involved not only with gastrointestinal infections, but also bacteremia, and sepsis. Molecular testing is available for detection in addition to the conventional isolation and culturing methodology. The infectious dose by ingestion was lowered to 350–800 organisms. The natural modes of infection include now additional routes such as person-to-person and groups at risk.
The BMBL-6 includes multiple updates for this bacteria. The general information includes updates on the current taxonomic classification. It includes one additional occupational infection when handling fetal membranes . Multiple edits to the section on laboratory safety were made, most notably the containment needed for handling non-avian strains of C. psittaci may be BSL-2 following BSL3 practices. Lastly, vaccination against Chlamydia spp was included as not available.
This section was re-named in the BMBL-6 to include C. botulinum. The information about the toxin [lab safety, vaccines, post-exposure treatment] has been moved to Section VIII-G.
Clostridioides difficile in a new addition to the BMBL-6. It is the most common cause of infectious diarrhea in hospitalized patients. This section includes a documented occupational infection. The natural modes of infection are discussed, transmission primarily occurs through the fecal-oral route or hand-to-hand contact. Laboratory safety includes containment at BSL-2 practices, containment equipment, and facilities are recommended for all manipulations. ABSL-2 facilities are recommended for in vivo studies. There is a requirement for CDC and/or USDA importation permits.

Very minor changes or updates were made to the information for Clostridium tetani in the BMBL-6. The information about the number of cases of tetanus reported to CDC from 1998 through 2000 was updated to 233. A statement was added that Tetanus is considered a medical emergency and treatment with human tetanus immune globulin is recommended.

The BMBL-6 includes updates to the agent information, notably, the gene for the exotoxin produced by the C. diphtheriae can also infect non-toxigenic strains. An additional occupational infection caused by C. ulcerans, a zoonotic pathogen, was included in the BMBL-6. Lastly, the natural modes of infection have additional information on how long C. diphtheriae is present in nasopharynx and skin lessons.
The BMBL-6 has updates to the agent information related to the incubation period and symptoms. This section also includes the classification of F. tularensis subsp. novicida as a separate species. The Laboratory Safety section refers to the Public Health Agency of Canada’s Pathogen Safety Data Sheet for F. tularensis for survival times on different surfaces and updated the list of strains with reduced virulence that may be handled at BSL-2. This version of the BMBL references a vaccine currently under FDA review for tularemia. The Special issues includes a cautionary statement that samples processed using MALDI-TOF MS are not directly spotted on plates in the open and are extracted instead to kill viable bacteria prior to analysis.
There are very minor changes to the information of Helicobacter species in the BMBL-6. The number of recognized species was updated to 37 (including 14 that were isolated from humans).
The agent information for Legionella spp. updated the number of species, subspecies and serogroup. One probable case of human-to-human transmission was referenced under the Occupational Infections.
The agent information for Leptospira updated the number of species including pathogenic and saprophytic species. The BMBL-6 also includes updates on the time this microbe persists on certain surfaces and one reference to a potential inhalation of contaminated droplets of urine or water.
The BMBL-6 has minor revisions through this section. Notably, the “should” used when discussing that pregnant women are advised of the risk of exposure to L. monocytogenes was reworded to “it is recommended”.
The BMBL-6 added M. lepromatosis, a related species, that can cause a similar disease to leprosy. This update also includes other modes of transmission involving animals and humans and a reference to recent increased cases of leprosy in the US. However, the inadvertent human-to-human transmission by accidental needle stick included in the BMBL-5 was removed from the new edition. Endemic animal forms of the disease have also been described from related bacterial species.
The BMBL-6 added recently described species M. canettii, M. mungi and M. orygis. The occupational Infections section includes now a reference to the multidrug-resistant (MDR) and extensively resistant (XDR) strains as being of particular concern. Additional modes of infection include latent infections that may reactivate, and disseminated tuberculosis. The BMBL-6 includes following BSL-3 practices for animal studies (rodents) when conducted in ABSL-2 containment. Lastly, the surveillance section includes the use of the FDA-approved Interferon Gamma Release Assay (IGRA) as an alternative to PPDskin testing when skin tests have been negative.
The information for these organisms has been updated in the BMBL-6 to reflect current knowledge of this species. > 150 Mycobacterium species have been identified. Some of these species are slow growing while others grow rapidly. Mycobacterial isolates not part of the M. tuberculosis complex are now called nontuberculous Mycobacteria (NTM) or Mycobacteria other than tuberculosis (MOTT). New to the BMBL-6 is the reference to an LAI with Mycobacterium spp.via needle stick while conducting an experiment in mice.
Minor updates were made to this section to update incidence rates of gonorrhea. A special issue was included to reference the emergence of an extensively drug-resistant strain (XDR) and other antimicrobial resistant strains. As such, certain antibiotics are not recommended for treatment of uncomplicated gonorrhea.
The BMBL-6 updated the agent information for N. meningitidis to include one additional serogroup X and specific potentially infected source materials such as fluids from sterile sites. The laboratory safety practices emphasize handling bacterial cultures and inoculation of clinical specimens inside the BSC. This update also includes the N. meningitidis vaccines currently available and recommendations for laboratorians potentially exposed to this bacteria.
The BMBL-6 includes recommendations for antimicrobial therapy, additional information about modes of infection and the problem of antimicrobial resistance of Salmonella spp. This update also mentions that vaccines against non-typhoidal strains are not available.
This update includes the infectious dose for S. Typhi at <1000 organisms, instead of <103 organisms. The laboratory safety and containment recommendations removed the specifics associated with PPE use such as the splash shields, face protection, gowns, and gloves.
This agent summary is limited to Shiga toxin-producing E. coli. The BMBL-6 updated the number of E. coli species, the survival of the bacteria on environmental surfaces. Importantly, the details included in BMBL-5 for laboratory safety have been condensed to use of PPE, handwashing, and decontamination of surfaces.
Minor updates were incorporated in the introductory paragraphs to isolation methods from infected source materials.
This is a new agent summary added in the BMBL-6. S. aureus is a Gram-positive bacterium and is found to be associated with minor to severe disease. Ingestion of food containing enterotoxins results in infection. No vaccines are available for human use. Lab workers can become exposed to the agent through broken skin, mucous membranes, contaminated surfaces, parenteral inoculation, ingestion and while handling cultures. BSL-2 practices, containment equipment, and facilities are recommended for all activities utilizing known/potentially infected clinical materials and cultures. ABSL-2 facilities are recommended for studies utilizing infected laboratory animals. Importation of this agent requires CDC and/or USDA import permits.
The description of Treponema pallidum, the causative organism for syphilis, bejel, and yaws has remained unaltered in BMBL-6 with the exception that the nomenclature was updated for the subspecies (example T. pallidum subsp. pallidum).
The BMBL-6 has updated agent summary for the Vibrio genus, which harbor several species including V. cholerae, which causes human enteritis. Fatal cases of septicemia were included in the modes of infection in immunocompromised or individuals with pre-existing conditions. Importantly, references to LAIs of V. cholerae or V. parahaemolyticus associated with the use of syringes, spill clean-up, or handling of infected animals are included in this edition. Lastly, the Vaccines section has been updated to reflect current availability and recommendations.
New information was added about the mortality rate and the different manifestations of the disease. A LAI involving an attenuated strain KIM D27 was fatal. Attenuated strains such as A1122 can be handled using BSL-2 practices, containment equipment and facilities. The BMBL-6 includes caution when automated systems are used to identify this bacteria to avoid misidentification.