Deborah Lehmann, Australia

Serotype 2 was a major cause of pneumococcal pneumonia about 100 years ago and then disappeared. Recently, serotype 2 re-emerged in many countries, including Bangladesh and associated with meningitis. This study aims to understand genomic and epidemiological characteristics of newly emerged serotype 2 strains.

Methods

Whole-genome sequencing was performed on 146 isolates (invasive= 125, carriage= 8 and other= 5, unknown= 8) collected between 1989 and 2017. Data were analyzed for comparative genomics, antimicrobial resistance and molecular typing.

Results

Isolates were from 16 countries, mostly in Asia (n=93), Africa (n=23) and Oceania (n=26). Bangladesh (n=66) and Papua New Guinea (n=26) contributed 63% of the isolates. Among the known clinical conditions, 80% (91/113) were from meningitis. All isolates belonged to GPSC96 lineage and descended from two predominant sequence types: ST74 found in Asia and Africa, and ST1504 found in Papua New Guinea and Israel. Almost all isolates were sensitive to all antibiotics. No significant genetic differences were detected between invasive and carriage isolates.

Conclusions

Our findings don’t explain why the recent increase in serotype 2 occurred but exclude an outbreak or emergence of an antimicrobial-resistant strain as the cause. These isolates have unusually high propensity to be invasive, mostly causing meningitis.

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HIGH RATES OF MULTIPLE NASOPHARYNGEAL PNEUMOCOCCAL CARRIAGE IN CHILDREN WITH PNEUMONIA IN PAPUA NEW GUINEA FOLLOWING PNEUMOCOCCAL CONJUGATE VACCINE INTRODUCTION (ID 731)

Session Name

Vaccines - Impact of Vaccine programs and Serotype Replacement

Presenter

Rebecca Ford, Papua New Guinea

Authors

Abstract

Abstract

Background

Pneumococcal carriage rates in Papua New Guinean (PNG) children are among the highest globally. One aim of the multi-site PneuCAPTIVE study is to determine the impact of PCV13 (introduced in 2014) on nasopharyngeal carriage in PNG.

Methods

Nasopharyngeal (NP) swabs and blood were collected from children aged <5 years with moderate or severe pneumonia, and/or suspected meningitis at Eastern Highlands Provincial Hospital or outpatient clinics in Goroka (2016-2018). Pneumococci were identified and quantified by lytA qPCR, and serotyped by microarray. IPD was identified by standard blood culture.

Results

PCV13 coverage was 62%. 1043 were enrolled: 90% had pneumococcal carriage, with median density of 6.59 log₁₀ genome equivalents (GE)/ml (IQR 6.00-7.11). Serotype data were available on 914 cases: 37% were PCV13-types; and 55% had multiple pneumococcal-type carriage. 74 different serotypes and genetic lineages of acapsular pneumococci were identified, the most common being acapsular lineage NT2>19A>15B/C>16F>14. PCV13-type carriage was 28% in vaccinated children vs 46% in unvaccinated children. IPD was confirmed in 7 cases (vaccinated – serotype 1; unvaccinated – serotypes 2, 6B, 15F, 19A, 23A, 29): 4/7 carried the homologous serotype.

Conclusions

There is some evidence of PCV13 being effective against PCV13-types but the high diversity of serotypes in PNG warrants extended valency vaccines.

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LACK OF IMPACT OF PNEUMOCOCCAL CONJUGATE VACCINATION ON SEROTYPE-SPECIFIC PNEUMOCOCCAL CARRIAGE DENSITY IN PAPUA NEW GUINEAN INFANTS (ID 769)

Session Name

Vaccines - Impact of Vaccine programs and Serotype Replacement

Presenter

Kate Britton, Australia

Authors

A DYNAMIC MODEL TO DETERMINE FACTORS REQUIRED FOR ELIMINATION OF VACCINE-TYPE CARRIAGE FOLLOWING PNEUMOCOCCAL CONJUGATE VACCINE INTRODUCTION IN THE ASIA-PACIFIC (ID 850)

Session Name

Population Sciences - Epidemiology, Economics, and Mathematical Modelling

Presenter

Jocelyn Chan,

Authors

ANTIMICROBIAL SUSCEPTIBILITY OF PNEUMOCOCCAL CARRIAGE ISOLATES AMONG PAPUA NEW GUINEAN CHILDREN VACCINATED WITH 10-VALENT OR 13-VALENT PNEUMOCOCCAL CONJUGATE VACCINES (PCVS) (ID 388)

Session Name

Vaccines - Impact of Vaccine programs and Serotype Replacement

Presenter

Tilda Orami, Papua New Guinea

Authors

DETERMINING THE PNEUMOCOCCAL CONJUGATE VACCINE COVERAGE REQUIRED FOR INDIRECT PROTECTION IN LAOS, MONGOLIA AND PAPUA NEW GUINEA (ID 851)

Session Name

Population Sciences - Epidemiology, Economics, and Mathematical Modelling

Presenter

Jocelyn Chan,

Authors