Influenza-like Illness Exacerbates Pneumococcal Carriage in Older Adults

Abstract

Background In older adults pneumococcal disease is strongly associated with respiratory viral infections, but the impact of viruses on Streptococcus pneumoniae carriage prevalence and load remains poorly understood. Here, we investigated the effects of influenza-like illness (ILI) on pneumococcal carriage in community-dwelling older adults. Methods We investigated the presence of pneumococcal DNA in saliva samples collected in the 2014/2015 influenza season from 232 individuals aged ≥60 years at ILI-onset, followed by sampling 2-3 weeks and 7-9 weeks after the first sample. We also sampled 194 age-matched controls twice 2-3 weeks apart. Pneumococcal DNA was detected with quantitative-PCRs targeting piaB and lytA genes in raw and in culture-enriched saliva. Bacterial and pneumococcal abundances were determined in raw saliva with 16S and piaB quantification. Results The prevalence of pneumococcus-positive samples was highest at onset of ILI (18% or 42/232) and lowest among controls (13% or 26/194, and 11% or 22/194, at the first and second sampling moment, respectively), though these differences were not significant. Pneumococcal carriage was associated with exposure to young children (OR:2.71, 95%CI 1.51-5.02, p<0.001), and among asymptomatic controls with presence of rhinovirus infection (OR:4.23; 95%CI 1.16-14.22, p<0.05). When compared with carriers among controls, pneumococcal absolute abundances were significantly higher at onset of ILI (p<0.01), and remained elevated beyond recovery from ILI (p<0.05). Finally, pneumococcal abundances were highest in carriage events newly-detected after ILI-onset (estimated geometric mean 1.21E -5, 95%CI 2.48E -7-2.41E -5, compared with pre-existing carriage). Conclusions ILI exacerbates pneumococcal colonization of the airways in older adults, and this effect persists beyond recovery from ILI.

The epidemiologic and biologic basis for classifying older age as a high-risk, immunocompromising condition for pneumococcal vaccine policy

“…The frequency [91] and density [43] of pneumococcal colonization are reported to be reduced in older adults, despite the incidence of pneumococcal CAP and IPD being highest in older age groups. However, recent studies appear to have resolved this seeming paradox, specifically by finding carriage prevalence of older adults approaching that in children when using molecular techniques and testing reservoirs other than the nasopharynx, such as the oropharynx and saliva [53,91,92]. Studies of experimental pneumococcal colonization indicate that colonization can be established in healthy older adults, but it failed to confer serotype-specific immunity [82].…”

Pneumococcal and Influenza Vaccination Rates and Pneumococcal Invasive Disease Rates Set Geographical and Ethnic Population Susceptibility to Serious COVID-19 Cases and Deaths

“…Respiratory viruses are well-known to condition the lungs to be more susceptible to bacterial super-infection [ 7 ] and were highly associated with severe disease and death in previous respiratory virus pandemics such as the Great Influenza pandemic of 1918–1919 [ 8 , 9 , 10 , 11 ] and severe acute respiratory disease (SARS) (reviewed in [ 12 ]). In particular, pneumococcal infections are found in up to 25% of people over the age of 60 with influenza-like illnesses regardless of viral cause [ 13 ]. Thus, while the pneumonias associated with SARS-CoV-2 were initially attributed exclusively to the virus, recent investigations have revealed high levels of fungal and bacterial coinfections in COVID-19 cases comparable to or higher than those found in hospitalized influenza cases [ 12 , 13 , 14 , 15 , 16 , 17 ].…”

“…In particular, pneumococcal infections are found in up to 25% of people over the age of 60 with influenza-like illnesses regardless of viral cause [ 13 ]. Thus, while the pneumonias associated with SARS-CoV-2 were initially attributed exclusively to the virus, recent investigations have revealed high levels of fungal and bacterial coinfections in COVID-19 cases comparable to or higher than those found in hospitalized influenza cases [ 12 , 13 , 14 , 15 , 16 , 17 ]. Lai et al [ 16 ], for example, have reviewed some of the relevant literature, concluding that “The prevalence of coinfection was variable among COVID-19 patients in different studies, however, it could be up to 50% among non-survivors.…”

Detection ofNeisseria meningitidisin Saliva and Oropharyngeal Samples from College Students

“…DNA was extracted from 100 µl of harvest of culture-enriched samples using DNeasy Blood & Tissue kit (Qiagen, Hilden, Germany) as previously described [22]. DNA eluted into 100 μl sample volume was tested in quantitative-PCRs (qPCRs) using primers and probes (Eurogentec, Seraing, Belgium) targeting sequences within metA , a gene encoding for a periplasmic protein, and a capsule transporter gene ctrA [23, 24].…”