Varun S,

Poster Author Of 3 e-Posters

Author Of 3 Presentations

GENETIC DIVERSITY OF CBPA AMONG INVASIVE STREPTOCOCCUS PNEUMONIAE ISOLATES FROM INDIA (ID 1152)

Abstract

Background

Streptococcus pneumoniae is a human opportunistic pathogen responsible for morbidity and mortality worldwide. Pneumococcal surface protein, Choline-binding protein A (CbpA) plays a key biological role in nasopharyngeal colonization and modulating the immune response to pneumococci. We have analyzed the genetic diversity of cbpA in invasive isolates.

Methods

264 invasive S.pneumoniae isolates collected from 2010-2018, were sequenced on Illumina Platform. The CRL in-house bioinformatics pipeline was used to extract gene sequences, alignment and phylogeny analysis. Allelic variations of CbpA gene was analyzed by comparing the identity with a well-defined virulent strain of S. pneumoniae TIGR4.

Results

Gene cbpA was identified in 261(99%) of the 264 genomes. The sequences were highly polymorphic at both nucleotide and amino acid levels. Similarity of cbpA gene ranged from 65 – 98%, while 80- 99% homology was observed at amino acid level. Amino acid residues with similar physicochemical properties aligned allowing the identification of broadly conserved CbpA domains.

Conclusions

Due to high polymorphism at the cbpA locus, analysis of this loci from different isolates highlights how sequence diversity correlates with structural variation. The conserved epitope regions of the CbpA protein fragments can be exploited to develop more efficacious serotype-independent vaccines.

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PREDOMINANCE OF CLONAL COMPLEX 320 AMONG INVASIVE STREPTOCOCCUS PNEUMONIAE SEROTYPE 19F ISOLATES FROM INDIA IN PRE-VACCINE ERA. (ID 1203)

Abstract

Background

Worldwide Streptococcus pneumoniae serotype 19F, often multi-drug resistant, has emerged as an important pathogen associated with invasive pneumococcal disease (IPD). The aim of the study was to characterize invasive serotype 19F isolates collected from India in pre-vaccine era.

Methods

Among 480 pneumococcal isolates collected across India from 2010-2018, 38 belonged to serotype 19F (8%). These were sequenced on Illumina Platform. The sequence data was analysed for serotype, clonal complex, pilus islets and MLST using the CDC pipeline

Results

Overall, 11 STs encompassing in 4 GPSCs and 3 clonal complexes (CCs) were identified. The most prevalent strain of serotype 19F was GPSC1 (n=31, CC320), followed by GPSC10 (n=3, CC10879). CC320 was the major clonal complex (n=33) with ST236 (n=7), ST271 (n=7), ST320 (n=7), ST2697 (n=7), ST2854 (n=2) and ST651, ST1396, ST8359 (n=1 each). A majority of GPSC1 isolates (30/31) had pilus 1 & 2 while GPSC10 isolates were negative for both. All GPSC1 isolates and GPSC10 isolates were resistance to at least three antibiotic classes

Conclusions

This analysis identified CC320 as the major lineage among serotype 19F isolates pre-PCV vaccination in India. Overall, serotype 19F isolates were found to be multi-drug resistant with a high percentage of pili genes present.

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ZMPB ALLELIC VARIATION IN STREPTOCOCCUS PNEUMONIAE ISOLATES CAUSING MENINGITIS IN INDIAN POPULATION (ID 1138)

Abstract

Background

Streptococcus pneumoniae is a leading cause of meningitis. Intense inflammatory response observed in meningitis is partially attributed to zinc metalloprotease encoded by zmpB in pneumococcal strains. We aimed to study allelic variations of zmpB among isolates obtained from Meningitis patients

Methods

36 cerebrospinal fluid (CSF) isolates collected across the country from 2009-2016 were sequenced on Illumina platform. The CRL in-house bioinformatics pipeline was used to extract gene sequences, alignment and phylogeny analysis. SeroBA was used to determine serotype. Allelic variations of zmpB gene was analyzed by comparing the identity with the virulent strain S. pneumoniae TIGR4.

Results

36 pneumococcal isolates belong to 24 serotypes with 19F(n=5) as dominant type. Non-PCV13 vaccine serotypes constituted 50% of the isolates(n=18). The isolates were assigned to 28 sequence clusters, among them GPSC10(n=4) & GPSC2(n=3) were predominant.32 of 36 isolates showed 21 to 88% of sequence variation, while remaining 4 isolates showed sequence similarity of 98% with the TIGR4. Allelic variations did not affect the protein coding region analysis and conserved domains of ZmpB protein was identified in all isolates.

Conclusions

The findings provide insight on the allelic variations of zmpB, indicating there is a high degree of polymorphism in the sequence of zmpB in pneumococci causing meningitis.

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