Three Workers, One Production Line: Multidrug-Resistant TB in Ohio Food Plants

Multidrug-resistant tuberculosis (MDR TB) — TB that resists isoniazid and rifampin, the two cornerstone first-line drugs — is rare in the United States: under 3% of TB cases every year since 1993, and 98 of 9,025 cases in 2018. So when the Ohio Department of Health (ODH) reported three MDR TB cases in 2018–2019 among people who worked at the same food processing plant, and whole genome sequencing showed the three bacterial samples were genetically identical, investigators suspected workplace transmission.

What investigators found

ODH began investigating in February 2019, and a CDC team — including the Division of Tuberculosis Elimination and the National Institute for Occupational Safety and Health (NIOSH) — arrived on April 14, 2019. The team reviewed medical and employment records, interviewed key informants and toured the plant.

• All three patients worked at facility A, which stayed open throughout. The third also worked at facility B, which had closed in an unrelated business restructuring before the investigation began; a separate NIOSH team had visited it earlier for a health hazard evaluation after learning an employee had MDR TB.
• The first patient was born in one of the 30 countries the World Health Organization lists as having a high prevalence of MDR TB. With MDR TB so rare in the U.S., and no other matching strains in the national molecular surveillance database, that patient was likely infected there.
• While the first patient was infectious, the second and third patients worked on the same food production line for at least 54 days and 7 days — minimums, because daily work records were incomplete. No other place or exposure linked the three.

Tracing the contacts

Investigators identified 971 contacts, 941 of them at work, most born outside the United States. Of the 478 at highest risk — 448 workplace and 30 personal contacts — testing was still under way when the investigation closed on April 26, 2019:

All three patients had recovered or were recovering, and no further cases were found. ODH continues working with local partners to test and treat contacts with latent TB infection and to watch for new cases.

Lessons

• Think TB. Its signs are nonspecific — cough, chest pain, coughing up blood, weight loss, fever, chills, night sweats, weakness, fatigue, loss of appetite — so providers should consider it, especially in people with risk factors such as birth in an area with high TB rates.
• Test for resistance quickly. Rapid molecular drug-resistance testing is warranted for patients with risk factors for drug-resistant TB: not completing or adhering to treatment, incorrect treatment, prior TB treatment, living where drug-resistant TB is common, or contact with a drug-resistant case.
• Build trust. Investigations succeed when health agencies engage communities with higher TB rates — communicating in culturally sensitive ways, offering incentives for testing and treatment, providing transportation, using mobile clinics and educating the whole community.

Sources

Based on Amish Talwar, Rebekah Stewart, Sandy P. Althomsons, et al., "Notes from the Field: Multidrug-Resistant Tuberculosis Among Workers at Two Food Processing Facilities — Ohio, 2018–2019," Morbidity and Mortality Weekly Report, volume 69, Centers for Disease Control and Prevention; a work of the United States government in the public domain.