Nasopharyngeal Carriage of Streptococcus Pneumoniae and Serotypes Indentified among Nursing Home Residents in Comparison to the Elderly and Patients Younger than 65 Years Living in Domestic Environment

High Levels of Detection of Nonpneumococcal Species of Streptococcus in Saliva from Adults in the United States

While the sensitivity of detection of pneumococcal carriage can be improved by testing respiratory tract samples with quantitative PCR (qPCR), concerns have been raised regarding the specificity of this approach. We therefore investigated the reliability of the widely used lytA qPCR assay when applied to saliva samples from older adults in relation to a more specific qPCR assay (piaB). During the autumn/winter seasons of 2018/2019 and 2019/2020, saliva was collected at multiple time points from 103 healthy adults aged 21 to 39 (n = 34) and >64 (n = 69) years (n = 344 total samples). Following culture enrichment, extracted DNA was tested using qPCR for piaB and lytA. By sequencing the variable region of rpsB (S2 typing), we identified the species of bacteria isolated from samples testing lytA-positive only. While 30 of 344 (8.7%) saliva samples (16.5% individuals) tested qPCR-positive for both piaB and lytA, 52 (15.1%) samples tested lytA-positive only. No samples tested piaB-positive only. Through extensive reculture attempts of the lytA-positive samples collected in 2018/2019, we isolated 23 strains (in 8 samples from 5 individuals) that were also qPCR-positive for only lytA. Sequencing determined that Streptococcus mitis and Streptococcus infantis were predominantly responsible for this lytA-positive qPCR signal. We identified a comparatively large proportion of samples generating positive signals with the widely used lytA qPCR and identified nonpneumococcal Streptococcus species responsible for this signal. This highlights the importance of testing for the presence of multiple gene targets in tandem for reliable and specific detection of pneumococcus in polymicrobial respiratory tract samples. IMPORTANCE Testing saliva samples with quantitative PCR (qPCR) improves the sensitivity of detection of pneumococcal carriage. The qPCR assay targeting lytA, the gene encoding the major pneumococcal autolysin, has become widely accepted for the identification of pneumococcus and is even considered the "gold standard" by many. However, when applying this approach to investigate the prevalence of pneumococcal carriage in adults in New Haven, CT, USA, we identified nonpneumococcal Streptococcus spp. that generate positive signals in this widely used assay. By testing also for piaB (encoding the iron acquisition ABC transporter lipoprotein, PiaB), our findings demonstrate the importance of testing for the presence of multiple gene targets in tandem for reliable molecular detection of pneumococcus in respiratory tract samples; targeting only lytA may lead to an overestimation of true carriage rates.

Pneumococcal carriage in adults aged 50 years and older in outpatient health care facility during pandemic COVID-19 in Novi Sad, Serbia

Background

Data related to carriage of Streptococcus pneumoniae (Spn) and antimicrobial resistance patterns in middle-aged and older adults are limited. We assessed the carriage of Spn, and its antibiotic resistance patterns, among participants ≥50 years of age living in the city of Novi Sad during the second year of COVID-19 pandemic.

Methods

Analysis of prospectively collected data among participants with or without symptoms of upper respiratory tract infection who visited their elected physicians in the Primary Health Care Centre of Novi Sad (outpatient facility) was conducted from May 18, 2021 to December 7, 2021. Both nasopharyngeal (NP) and oropharyngeal (OP) samples from each participant were collected.

Results

A total of 1042 samples from 521 study subjects (1 NP and 1 OP sample from each person) were collected. Sixteen samples from the same number of persons (3.1%, 95% confidence interval: 1.76%-4.94%) were culture positive for the presence of Spn. Overall, the median age of study participants was 71 years (range, 50–93 years; 90th percentile, 77 years), and most (197/521, 37.8%) of them were 70–79 years of age. A majority of the study subjects were: females (324/521; 62.2%), sampled during May and June 2021 (376/521, 72.2%), those who did not have contact with children aged 0–10 years in the family (403/521; 77.4%), without smokers in the household (443/521; 85.0%), and those who did not receive vaccine against Spn (519/521; 99.6%). Out of 16 Spn positive samples, for six participants, Spn carriage serotypes were obtained and there were four vaccine (6A, 11A, 15B, and 18C) serotypes, and two (6C and 35F) non-vaccine serotypes. Remaining 10 (62.50%) samples were non-typeable isolates of pneumococci. Among four vaccine serotypes, two (6A and 18C) were represented in PCV13, and 18C along with the other two (11A and 15B) in PPSV23 vaccine. The highest level of resistance of Spn isolates was observed for erythromycin, (10 or 62.50%), and tetracycline, (7 or 43.75%), one isolate showed resistance to penicillin, ampicillin, and amoxicillin/amoxicillin-clavulanic acid, while none of them were resistant to ceftriaxone, trimethoprim/sulfamethoxazole and levofloxacin. There were three multi-drug resistant isolates; one was identified as 6C (non-vaccine serotype), and two other were non-typeable isolates of Spn.

Conclusions

In this first study conducted in Serbia on Spn carriage in adults ≥50 years of age, we found low prevalence of Spn carriage and identified 6 serotypes of Spn, four of which were represented in vaccines. These results may support future Spn colonization studies among middle-aged and older adults.

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

This study examines the relationship of pneumococcal vaccination rates, influenza, measles-mumps-rubella (MMR) diphtheria-tetanus-pertussis vaccinations (DTP), polio, Haemophilus influenzae type B (Hib), and Bacillus Calmette-Guerin (tuberculosis) vaccination rates to COVID-19 case and death rates for 51 nations that have high rates of COVID-19 testing and for which nearly complete childhood, at-risk adult and elderly pneumococcal vaccination data were available. The study is unique in a large number of nations examined, the range of vaccine controls, in testing effects of combinations of vaccinations, and in examining the relationship of COVID-19 and vaccination rates to invasive pneumococcal disease (IPD). Analysis of Italian regions and the states of the United States were also performed. Significant positive correlations were found between IPD (but not lower respiratory infections) and COVID-19 rates, while significant negative correlations were found between pneumococcal vaccination and COVID-19 rates. Influenza and MMR vaccination rates were negatively correlated with lower respiratory infection (LRI) rates and may synergize with pneumococcal vaccination rates to protect against COVID-19. Pneumococcal and influenza vaccination rates were independent of other vaccination rates. These results suggest that endemic rates of bacterial pneumonias, for which pneumococci are a sentinel, may set regional and national susceptibility to severe COVID-19 disease and death.

A comparative profile of oropharyngeal colonization of Streptococcus pneumoniae and Hemophilus influenzae among HealthCare Workers (HCW) in a tertiary care hospital and non-healthcare individuals

Introduction

Streptococcus pneumoniae and Hemophilus influenzae are two major bacterial human pathogens responsible for causing both acute respiratory tract and life threatening invasive infections. Oropharyngeal carriage of these isolates can lead to its transmission frequently in healthcare settings between patients and HealthCare workers (HCW) and also common among population living in crowded communities resulting in serious invasive infections. Furthermore, awareness about preventive measures including appropriate vaccination against these bacterial infections, oropharyngeal carrier status, prevalent serotypes and the antimicrobial susceptibility pattern these bacterial strains among HCW and Non-HCW in the community in India remains inadequate. Therefore the current study is aimed to understand the prevalence of oropharyngeal carrier status, prevalent serotypes and antimicrobial susceptibility profile of these organisms among HCW and non-HCW.

Methods

A total of 200 oropharyngeal swabs were collected from HealthCare Workers and 200 from Non-Health care individuals of age 18 to 70. Antimicrobial susceptibility profile was studied for Pneumococci and H. influenzae. Specific serotypes for the carrier isolates of Pneumococci were identified using primers appropriate to the prevalent serotypes by multiplex PCR.

Results

About 30% of the HCW were colonized with S.pneumoniae and H. influenzae (P ≤ 0.0001). Out of which 19% of them were S.pneumoniae and 11% were H. influenzae. A total of 23% of the Non-HCW was colonized with S. pneumoniae and H. influenzae. Out of which 16% had pneumococcal carriage and 7% had H. influenzae. Individuals in the age group 56-70 years had significantly a greater prevalence rate when compared to young people (P = 0.0014). Thus in this study 30% of the HCW and 23% of the Non-HCW were colonized with S. pneumoniae and H. influenzae. Both Pneumococci and H. influenzae showed 100% susceptibility to Penicillin and other cephalosporins. However, Pneumococcal isolates from HCW showed better susceptibility towards erythromycin & clindamycin whereas isolates from Non- HCW showed better susceptibility towards ofloxacin and tetracycline. Serotypes detected in our study include 19F, 3, 1 and 5.

Conclusions

The present study gives a greater prevalence rate of S.pneumoniae and H. influenzae among HCW when compared to Non-HCW. This will definitely increase horizontal spread of infections and further accelerate the occupational risk. Increased carrier state prevalence among old age group underscores the importance of vaccination among these individuals.