[Federal Register Volume 88, Number 153 (Thursday, August 10, 2023)]
[Rules and Regulations]
[Page 54247]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16929]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES

42 CFR Part 73


Select Agent Determination Concerning Coxiella burnetii Phase II, 
Nine Mile Strain, Plaque Purified Clone 4 With Reversion to Wildtype 
cbu0533

AGENCY: Centers for Disease Control and Prevention (CDC), Department of 
Health and Human Services (HHS).

ACTION: Determination.

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SUMMARY: The Centers for Disease Control and Prevention (CDC), located 
within the Department of Health and Human Services (HHS), has 
determined that an excluded attenuated strain, Coxiella burnetii Phase 
II, Nine Mile Strain, plaque purified clone 4, has, in one instance, 
been shown to spontaneously mutate when passaged in vivo. The resulting 
mutant, C. burnetii Phase II, Nine Mile Strain, plaque purified clone 4 
with reversion to wildtype cbu0533, has enhanced pathogenicity and 
virulence. Therefore, C. burnetii Phase II, Nine Mile Strain, plaque 
purified clone 4 with reversion to wildtype cbu0533 is not an excluded 
strain but is a select agent and subject to the HHS select agent and 
toxin regulations.

DATES: This determination is effective August 10, 2023.

FOR FURTHER INFORMATION CONTACT: Samuel S. Edwin Ph.D., Director, 
Division of Select Agents and Toxins, Centers for Disease Control and 
Prevention, 1600 Clifton Road NE, Mailstop H21-4, Atlanta, Georgia 
30329, Telephone: (404) 718-2000.

SUPPLEMENTARY INFORMATION: Coxiella burnetti is a select agent that is 
regulated pursuant to the HHS select agent and toxin regulations (42 
CFR part 73). C. burnetii is a gram-negative intracellular bacterium 
that causes Q Fever. Q Fever is a zoonotic disease that causes flu-like 
symptoms in humans, including fever, chills, fatigue, and muscle pain. 
Humans become infected when they are in close contact with infected 
animal fluids and products.
    The HHS select agent regulations (42 CFR part 73) established a 
process by which an attenuated strain of a select biological agent that 
does not have the potential to pose a severe threat to public health 
and safety may be excluded from the requirements of the regulations. On 
October 15, 2003, C. burnetii Phase II, Nine Mile Strain, plaque 
purified clone 4 was excluded from HHS select agent regulations as it 
does not pose a significant threat to public health and safety (https://selectagents.gov/sat/exclusions/hhs.htm).
    As set forth under 42 CFR 73.4(e)(2), if an excluded attenuated 
strain is subjected to any manipulation that restores or enhances its 
virulence, the resulting select agent will be subject to the 
requirements of the regulations. On March 20, 2023, an entity informed 
CDC of a reversion whereby C. burnetii Phase II, Nine Mile Strain, 
plaque purified clone 4 spontaneously mutated. The C. burnetii Phase 
II, Nine Mile Strain, plaque purified clone 4 with reversion to 
wildtype cbu0533 displayed increased pathogenicity and virulence. The 
entity stated that after the excluded strain was injected into guinea 
pigs, a spontaneous reversion occurred that resulted in a mutant strain 
of the agent and the guinea pigs subsequently exhibited elevated fever 
and weight loss. The genetic mutation that led to the mutant strain was 
the reversion and restoration of a deletion in the cbu0533 gene. CDC 
subject matter experts have determined that this reversion in cbu0533 
restored virulence and pathogenicity. Therefore, C. burnetii Phase II, 
Nine Mile Strain, plaque purified clone 4 with reversion to wildtype 
cbu0533 is determined to be a select agent and subject to 42 CFR part 
73.

Xavier Becerra,
Secretary, Department of Health and Human Services.
[FR Doc. 2023-16929 Filed 8-9-23; 8:45 am]
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