Association of Upper Respiratory Streptococcus pneumoniae Colonization With Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Adults

Abstract

Background: Streptococcus pneumoniae interacts with numerous viral respiratory pathogens in the upper airway. It is unclear whether similar interactions occur with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: We collected saliva specimens from working-age adults undergoing SARS-CoV-2 molecular testing at outpatient clinics and via mobile community-outreach testing between July and November 2020 in Monterey County, California. After bacterial culture enrichment, we tested for pneumococci by means of quantitative polymerase chain reaction targeting the lytA and piaB genes, and we measured associations with SARS-CoV-2 infection using conditional logistic regression.

Results: Analyses included 1278 participants, with 564 enrolled in clinics and 714 enrolled through outreach-based testing. The prevalence of pneumococcal carriage was 9.2% (117 of 1278) among all participants (11.2% [63 of 564] in clinic-based testing and 7.6% [54 of 714] in outreach-based testing). The prevalence of SARS-CoV-2 infection was 27.4% (32 of 117) among pneumococcal carriers and 9.6% (112 of 1161) among noncarriers (adjusted odds ratio [aOR], 2.73 [95% confidence interval (CI): 1.58-4.69). Associations between SARS-CoV-2 infection and pneumococcal carriage were enhanced in the clinic-based sample (aOR, 4.01 [95% CI: 2.08-7.75]) and among symptomatic participants (3.38 [1.35-8.40]), compared with findings within the outreach-based sample and among asymptomatic participants. The adjusted odds of SARS-CoV-2 coinfection increased 1.24-fold (95% CI: 1.00-1.55-fold) for each 1-unit decrease in piaB quantitative polymerase chain reaction cycle threshold value among pneumococcal carriers. Finally, pneumococcal carriage modified the association of SARS-CoV-2 infection with recent exposure to a suspected coronavirus disease 2019 case (aOR, 7.64 [95% CI: 1.91-30.7] and 3.29 [1.94-5.59]) among pneumococcal carriers and noncarriers, respectively).

Conclusions: Associations of pneumococcal carriage detection and density with SARS-CoV-2 suggest a synergistic relationship in the upper airway. Longitudinal studies are needed to determine interaction mechanisms between pneumococci and SARS-CoV-2.

Keywords: SARS-CoV-2; carriage; pneumococcus; viral-bacterial interaction.