Ravinder Kaur, United States of America
Rochester General Hospital Research Institute Center for Infectious Disease and ImmunologyPresenter of 4 Presentations
SERUM ANTIBODY LEVELS TO PNEUMOCOCCAL POLYSACCHARIDES 22F, 33F, 19A AND 6A THAT CORRELATE WITH PROTECTION FROM ACUTE OTITIS IN CHILDREN IN ROCHESTER NY (ID 845)
Abstract
Background
Serotypes 22F and 33F have been added to a new 15-valent pneumococcal-conjugate vaccine (V114, Merck) because of their prevalence causing IPD. An effectiveness study to prove disease prevention for pneumococcal strains expressing 22F and/or 33F capsule would be challenging due to sample size required. A possible solution may be to demonstrate a serologic correlate of protection (COP) based on natural disease responses.
Methods
We evaluated anti-polysaccharide 22F and 33F antibody levels in 6-36 month old children before and after AOM infections caused by pneumococcal strains expressing 22F or 33F capsule. COP levels were inferred using generalized-linear models. To validate our approach testing of anti-19A and 6A antibody levels as comparators is underway.
Results
The contribution of antibody level to AOM risk was statistically significant for 22F (p=0.014) and 33F (p=0.006). We derived that a level of antibody=0.25µg/ml is a COP threshold for prevention of pneumococcal AOM infections caused by 22F and 33F strains. Among unvaccinated children 18-months olds, 62.5% had titers that exceeded this threshold for 22F.
Conclusions
We conclude that a level of antibody of 0.25μg/ml for 22F and 33F will be effective for preventing AOM in children if such levels are produced in response to V114.
DYNAMIC CHANGES IN STREPTOCOCCUS PNEUMONIAE STRAINS COLONIZING THE NASOPHARYNX AND CAUSING ACUTE OTITIS MEDIA IN CHILDREN AFTER 13-VALENT PNEUMOCOCCAL-CONJUGATE VACCINATION (PCV-13) 2015-2019 IN ROCHESTER NY. (ID 848)
Abstract
Background
After introduction of PCV-13 in the USA in 2010, emergence of replacement serotypes occurred. From our ongoing 14-year prospective study we report Streptococcus pneumoniae (Spn) strains colonizing the nasopharynx (NP) of children based on serotype, sequence type (ST) and antibiotic susceptibility along with otopathogens, Haemophilus influenzae (Hi) and Moraxella catarrhalis (Mcat) for years 2015-2019.
Methods
2059 visits (1528 healthy, 393 AOM and 138 AOM-follow-up visits) from 589 children, ages 6-36 months were included. 495 middle-ear fluid (MEF) were obtained during AOM by tympanocentesis.
Results
In the NP we isolated Mcat (39%) >Spn (32%) >Hi (12%) at healthy visits and Mcat=Spn (53%) >Hi (36%) at onset of AOM. MEF culture results were Hi (35%) >Spn (24%) >Mcat (15%) Correlation of NP and MEF isolates at onset of AOM was poor. In the NP, serotype 35B (18.3%/20.6%) >23B (17.9%/9.1%)>15B/C (10.6%/12%) predominated at healthy/at onset of AOM. 35B (22.4%) was the most common serotype isolated from MEF. ST558 and ST199 were the most common sequence types in healthy and AOM visits. Penicillin and erythromycin antibiotic-nonsusceptibility were most frequent among Spn isolates
Conclusions
Dynamic changes in pneumococcal prevalence and serotypes colonizing the NP and causing AOM occurred in 2015-2019.
COMPARISON OF PNEUMOCOCCAL-CONJUGATE VACCINE (PCV-13) CELLULAR AND ANTIBODY IMMUNE RESPONSES AFTER PRIMARY AND BOOSTER DOSES OF VACCINE IN CHILDREN FROM ROCHESTER NY (ID 884)
SEROTYPE 3 IS NOT A COMMON NASOPHARYNGEAL COLONIZER OR ACUTE OTITIS MEDIA PATHOGEN IN CHILDREN IN ROCHESTER, NY (ID 885)
Author Of 10 Presentations
DYNAMIC CHANGES IN STREPTOCOCCUS PNEUMONIAE STRAINS COLONIZING THE NASOPHARYNX AND CAUSING ACUTE OTITIS MEDIA IN CHILDREN AFTER 13-VALENT PNEUMOCOCCAL-CONJUGATE VACCINATION (PCV-13) 2015-2019 IN ROCHESTER NY. (ID 848)
Abstract
Background
After introduction of PCV-13 in the USA in 2010, emergence of replacement serotypes occurred. From our ongoing 14-year prospective study we report Streptococcus pneumoniae (Spn) strains colonizing the nasopharynx (NP) of children based on serotype, sequence type (ST) and antibiotic susceptibility along with otopathogens, Haemophilus influenzae (Hi) and Moraxella catarrhalis (Mcat) for years 2015-2019.
Methods
2059 visits (1528 healthy, 393 AOM and 138 AOM-follow-up visits) from 589 children, ages 6-36 months were included. 495 middle-ear fluid (MEF) were obtained during AOM by tympanocentesis.
Results
In the NP we isolated Mcat (39%) >Spn (32%) >Hi (12%) at healthy visits and Mcat=Spn (53%) >Hi (36%) at onset of AOM. MEF culture results were Hi (35%) >Spn (24%) >Mcat (15%) Correlation of NP and MEF isolates at onset of AOM was poor. In the NP, serotype 35B (18.3%/20.6%) >23B (17.9%/9.1%)>15B/C (10.6%/12%) predominated at healthy/at onset of AOM. 35B (22.4%) was the most common serotype isolated from MEF. ST558 and ST199 were the most common sequence types in healthy and AOM visits. Penicillin and erythromycin antibiotic-nonsusceptibility were most frequent among Spn isolates
Conclusions
Dynamic changes in pneumococcal prevalence and serotypes colonizing the NP and causing AOM occurred in 2015-2019.
MUCOSAL IGA ANTIBODY LEVELS TO PNEUMOCOCCAL VACCINE CANDIDATE PROTEIN PHTD ARE A BIOMARKER TO DISTINGUISH OTITIS-PRONE AND NON-OTITIS PRONE CHILDREN IN ROCHESTER, NY. (ID 953)
Abstract
Background
We previously found that higher nasopharyngeal (NP) antibody levels to vaccine candidate proteins PhtD, PcpA and Ply significantly correlated with reduced risk of AOM (Xu et al Clin Micro Infect 2017).
Methods
Mucosal NP IgA and IgG antibody levels to PhtD, PcpA, and PlyD were measured by ELISA from stringently-defined otitis prone (sOP) and non-otitis prone (NOP) children from Rochester NY at 7 specific time points between age 6 and 36 months old when they were healthy. Logistic regression modeling was used to determine if age-specific antibody levels could be used as a biomarker to identify the sOP child.
Results
Mucosal PhtD IgA, PcpA IgG and IgA, and PlyD IgA antibody levels were significantly lower among sOP children across the age span studied. Age-specific PhtD IgA levels during health proved a suitable biomarker to distinguish sOP from NOP (p< 0.001), AUC=0.81, sensitivity 0.84, specificity and 0.7. PhtD IgA predicted sOP status with average accuracy of 84% without knowledge of prior NP colonization or AOM infection history.
Conclusions
Age-specific mucosal PhtD IgA levels may be a useful biomarker to define children who are more likely to become otitis prone.
COMPARISON OF PNEUMOCOCCAL-CONJUGATE VACCINE (PCV-13) CELLULAR AND ANTIBODY IMMUNE RESPONSES AFTER PRIMARY AND BOOSTER DOSES OF VACCINE IN CHILDREN FROM ROCHESTER NY (ID 884)
SEROGROUP 35 RESPONSES IN QUELLUNG REACTION AND ANALYSIS USING WHOLE GENOME SEQUENCING OF NASOPHARYNGEAL AND MIDDLE EAR FLUID ISOLATES FROM CHILDREN IN ROCHESTER NY (ID 954)
Abstract
Background
For serogroup 35, definition of serotype 35A occurs if reactions are interpreted as negative using sera specific for 35B, 35C and 35F.
Methods
From 2015-2019, a random subset of pneumococci serogroup 35 nasopharyngeal and middle ear fluid isolates from Rochester NY children were analyzed using Quellung and whole-genome sequencing (WGS).
Results
23 isolates positive for serogroup 35 by Quellung analyzed by WGS showed that 18 strains had been identified as serotype 35A by Quelling that were 35B by WGS. The 18 strains were retested by Quellung and 14 were reconsidered as positive with serotype 35B typing sera. 4 isolates were repeatedly negative for 35B by Quellung. We analyzed the genetic features of these 4 atypical 35B isolates. One isolate had a mutation on wciB (Y to C). Analysis of noncapsular region identified one region showing low similarity to the typical 35B (35B in Quelling reaction and WGS). That region was about 35K bp, coding 31 proteins that showed less than 75% similarity with typical 35B strains in DNA.
Conclusions
Caution is essential during interpretation of Quellung reactions for serogroup 35. We identified 4 atypical strains of serotype 35B that may have differential capsule expression. Further analysis is ongoing.
MIDDLE-EAR FLUID AND NASO-OROPHARYNGEAL STREPTOCOCCUS PNEUMONIAE SEROTYPE DISTRIBUTION IN 13-VALENT PNEUMOCOCCAL CONJUGATE VACCINATED CHILDREN WITH AND WITHOUT ACUTE OTITIS MEDIA IN ROCHESTER, NEW YORK, 2010-2013 (ID 627)
SEROTYPE 3 IS NOT A COMMON NASOPHARYNGEAL COLONIZER OR ACUTE OTITIS MEDIA PATHOGEN IN CHILDREN IN ROCHESTER, NY (ID 885)
SEROTYPE DISTRIBUTION OF STREPTOCOCCUS PNEUMONIAE IN NASO-OROPHARYNGEAL CARRIAGE OF 13-VALENT PNEUMOCOCCAL CONJUGATE VACCINATED CHILDREN IN ROCHESTER, NEW YORK, 2010-2013 (ID 629)
EMERGENCE OF SEROTYPE 35B PNEUMOCOCCI AS A DOMINANT STRAIN CAUSING ACUTE OTITIS MEDIA IN ROCHESTER NY. (ID 948)
Abstract
Background
Our ongoing 14-year surveillance (2006-2020) in Rochester NY has tracked pneumococcal serotypes causing acute otitis media (AOM) in children age 6-36 months.
Methods
Pneumococci were identified by culture of middle ear fluid using tympanocentesis and nasopharyngeal swabs. Serotypes were determined by Quellung and whole genome sequencing (WGS) (using Illumina NextSeq500 or Pacific Biosciences RSII). Assemblies of 35B strains were aligned using LR216049 as reference. A dot plot was used to map overall sequence similarity between “old 35B” isolated prior to 2015 and “new 35B” isolated after 2015.
Results
Serotype 35B case/carriage ratio of old 35B was 0.13 and 1.17 for new 35B, p=0.0001, suggesting increased virulence. New 35B accounts for almost 25% of all pneumococcal isolates from children with AOM, MLST was the same for old and new 35B strains (type 558). 2149 genes were consistently identified among 39 strains of 35B with WGS. Specifically WGS alignments revealed a 20 kb region encoding 30 proteins that was inverted in the old 35B (2 strains) strains compared to the new 35B (3 strains). Further analysis is ongoing.
Conclusions
35B has emerged as a dominant otopathogen in recent years among children in Rochester NY. Increased virulence appears associated with genomic change.
SERUM ANTIBODY LEVELS TO PNEUMOCOCCAL POLYSACCHARIDES 22F, 33F, 19A AND 6A THAT CORRELATE WITH PROTECTION FROM ACUTE OTITIS IN CHILDREN IN ROCHESTER NY (ID 845)
Abstract
Background
Serotypes 22F and 33F have been added to a new 15-valent pneumococcal-conjugate vaccine (V114, Merck) because of their prevalence causing IPD. An effectiveness study to prove disease prevention for pneumococcal strains expressing 22F and/or 33F capsule would be challenging due to sample size required. A possible solution may be to demonstrate a serologic correlate of protection (COP) based on natural disease responses.
Methods
We evaluated anti-polysaccharide 22F and 33F antibody levels in 6-36 month old children before and after AOM infections caused by pneumococcal strains expressing 22F or 33F capsule. COP levels were inferred using generalized-linear models. To validate our approach testing of anti-19A and 6A antibody levels as comparators is underway.
Results
The contribution of antibody level to AOM risk was statistically significant for 22F (p=0.014) and 33F (p=0.006). We derived that a level of antibody=0.25µg/ml is a COP threshold for prevention of pneumococcal AOM infections caused by 22F and 33F strains. Among unvaccinated children 18-months olds, 62.5% had titers that exceeded this threshold for 22F.
Conclusions
We conclude that a level of antibody of 0.25μg/ml for 22F and 33F will be effective for preventing AOM in children if such levels are produced in response to V114.
COMPARISON OF IN-VITRO VIRULENCE GENE EXPRESSION AND NASOPHARYNGEAL INNATE HOST RESPONSE TO COLONIZER VS LOCALLY INVASIVE SEROTYPE 35B AND 15A STRAINS OF PNEUMOCOCCI, ROCHESTER NY. (ID 952)
Abstract
Background
Among Rochester NY children, a dramatic increase in nasopharyngeal colonization by non-vaccine serotypes 35B and 15A pneumococci occurred after introduction of PCV13. During years 2010-2013 serotype 35B infrequently caused acute otitis media compared to serotype 15A
Methods
We investigated differences in 14 virulence genes between 35B and 15A strains in-vitro and 9 host innate cytokine gene responses in the nasopharynx of children using RT-PCR, normalized with two housekeeping genes, as possible explanations for the difference in virulence.
Results
: Seven of 14 virulence genes were differentially regulated when comparing 35B and 15A strains. ComA, phtD and phtE were upregulated, ciaR, pcpA, nanA and CapD were downregulated. LuxS comD, spxB, spsA, lytA, lytB and Ply showed no difference. In the nasopharyngx, IL17 and IL23 production were >10 fold higher during 35B colonization compared to 15A colonization.
Conclusions
Low AOM case/carriage ratio of 35B from 2010-2013 in Rochester NY children was associated with differential regulation of known virulence factors and mucosal immunological responses.