Pneumococcal carriage and serotype distribution among residents and healthcare workers in long-term care facilities in Japan during the COVID-19 pandemic.

BACKGROUND

Streptococcus pneumoniae is a major cause of pneumonia in older adults, and long-term care facility (LTCF) residents are at high risk because of advanced age, multimorbidity, and the close contact environment. However, data on pneumococcal carriage and serotype distribution in LTCFs remain limited. This study evaluated pneumococcal carriage and serotype distribution among LTCF residents and healthcare workers.

METHODS

We conducted an observational study involving two LTCFs in Nagasaki, Japan, from October 2021 to March 2022, when COVID-19 infection control measures were implemented. Saliva samples were collected from residents and healthcare workers at up to five time-points, tested for the lytA gene, and serotyped using nanofluidic PCR. Healthcare worker characteristics were compared between those with and without pneumococcal carriage.

RESULTS

We included 188 residents (median age: 90 years; 84.6% female; 82.4% with dementia; 55.9% requiring full assistance) and 88 healthcare workers (median age: 42 years; 68.2% female). Among residents, six of 806 samples were positive (0.7%; 95% confidence interval [CI]: 0.3-1.6), and 2.1% (95% CI: 0.8-5.3) were positive at least once across the five time-points. Among healthcare workers, 21 of 417 samples were positive (5.0%; 95% CI: 3.3-7.6), and 13.6% (95% CI: 8.0-22.3) were positive at least once. Carriage prevalence was higher among healthcare workers living with children aged < 5 years (33.3% vs. 6.6%, p = 0.018). Five serotypes were detected in residents and 15 in healthcare workers; serotype 35B was most frequent in healthcare workers (33.3%), followed by 10 A and 9 N/9 L (25% each). Identical serotypes were detected in residents and healthcare workers, and several serotypes were identified on follow-up in the same individuals.

CONCLUSIONS

Pneumococcal carriage was low among LTCF residents, despite the high risk of pneumococcal disease. Post-pandemic studies are needed to clarify transmission dynamics under routine conditions.