Pneumococci causing invasive disease in children prior to the introduction of pneumococcal conjugate vaccine in Scotland

Clarke, Stuart C.; Jefferies, Johanna M.C.; Smith, Andrew; McMenamin, Jim; Mitchell, Tim; Edwards, Giles

doi:10.1099/jmm.0.46550-0

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…16 – 20 , 23 When compared globally to those observed in Latin America, North America, and Europe, the 10 prevalent serotypes prior to 2010 in the present study were comparably well represented in samples from elsewhere in the pre-PCV7 and early post-PCV7 eras. 2 , 5 , 6 , 9 , 22 , 26 , 33 – 37 …”

Section: Discussionmentioning

confidence: 99%

“…For instance, serotype 14 was represented by four STs in the USA and 12 STs in Scotland during the pre-PCV era, and quite striking was the absence of ST156 in Scotland. 33 , 37 , 39 ST156 has frequently occurred worldwide and was first described as serotype 9V; this has subsequently also been described as serotype 14 and as other serotypes. 25 , 57 Furthermore, ST156 is often associated with antibiotic resistance and is one of the well described PMEN clones (Spain 9V -ST156, PMEN3) that have spread globally, including within the Latin America region.…”

Section: Discussionmentioning

confidence: 99%

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Serotypes and genotypes of Streptococcus pneumoniae isolates from Trinidad and Tobago

Nurse-Lucas

McGee

Hawkins

et al. 2016

International Journal of Infectious Diseases

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SUMMARYObjectivesThere are currently 94 known pneumococcal capsular polysaccharide serotypes and their prevalence differs by geographic region and the period studied. Streptococcus pneumoniae infections have been diagnosed clinically in Trinidad and Tobago and other Caribbean countries, however data on the serotype and sequence type distributions in this country are limited. The objective of this study was to determine serotypes and multilocus sequence types (MLSTs) of invasive and non-invasive pneumococcal isolates from Trinidad and Tobago.MethodsNinety-eight pneumococcal isolates from several regional hospitals in the country were analyzed using both standard microbiological methods and molecular analysis. These isolates included invasive (n = 83) and selected non-invasive (n = 15) strains recovered before (n = 25) and after (n = 73) the introduction of the pneumococcal conjugate vaccine.ResultsMore than half of the isolates (54.1%) were recovered from children under 15 years of age, with the largest proportion being from children under 2 years of age (24.5%). The most prevalent serotypes were 19F (18.4%), 6B (15.3%), 23F (14.3%), 3 (11.2%), 19A (6.1%), 6A (5.1%), 14 (5.1%), and 9V (4.1%). The most common serotype/MLST combinations were 6B/ST138 (n = 10, 10.2%), 3/ST180 (n = 5, 5.1%), 23F/ST629 (n = 5, 5.1%), 19F/ST8398 (n = 4, 4.1%), and three each of 6B/ST145, 14/9V/ST156, 9V/ST162, 19A/320, and 3/ST10440.ConclusionsThis report provides the first glimpse of the prevailing pneumococcal sequence types in the country. Most of the isolates represented serotypes in the 10-valent (61.2% of isolates) and 13-valent (83.7%) pneumococcal conjugate vaccines. A detailed population study is warranted to fully determine the circulating pneumococcal sequence types. Furthermore, the implementation of an effective and continuous surveillance system in Trinidad and Tobago is paramount to monitor vaccine impact.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Serotypes and genotypes of Streptococcus pneumoniae isolates from Trinidad and Tobago

Nurse-Lucas

McGee

Hawkins

et al. 2016

International Journal of Infectious Diseases

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“…The most striking example of this was for serotype 14, for which we observed 15 different STs (Table 2). In a UK study carried out in Scotland, serotype 14 was the most common serotype isolated from paediatric IPD prior to PCV7 introduction (Clarke et al, 2006;Jefferies et al, 2010) and was represented by 12 STs of which ST9 and ST124 were by far the most common. In the present study, ST9 was also the most common (n511).…”

Section: Serotype/genotype Relationshipsmentioning

confidence: 99%

Molecular analysis of Streptococcus pneumoniae clones causing invasive disease in children in Singapore

Jefferies

Tee

Clarke

2011

Journal of Medical Microbiology

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Streptococcus pneumoniae remains a leading cause of serious paediatric disease. However, there are few published epidemiological data regarding invasive pneumococcal disease (IPD) in many countries in South East Asia, including Singapore. Baseline data for IPD are essential to inform policy regarding pneumococcal conjugate vaccine (PCV) use in Singapore. To our knowledge, this is the first study to use multilocus sequence typing (MLST) to investigate clonal relationships among Singaporean IPD isolates. We characterized 86 invasive pneumococci isolated from Singaporean children between 2001 and 2006 using serotyping and MLST. The objectives were to compare Singaporean MLST data to worldwide data and to assess serotype distribution in relation to current PCV formulations. We observed 50 sequence types (STs), a high proportion of which (n516) were novel STs. Despite the presence of these novel STs, serotype distribution was similar to that observed elsewhere. Serotypes 14, 6B, 19A and 19F accounted for 85 % of IPD cases. PCV7, PCV10 and PCV13 covered 85 %, 86 % and 97 % of IPD isolates, respectively. We have demonstrated a pressing need for larger studies to determine the molecular epidemiology and antibiotic susceptibility of circulating pneumococcal clones from both carriage and disease in Singapore. INTRODUCTIONDespite the fact that Streptococcus pneumoniae remains a leading cause of pneumonia and invasive disease in children worldwide, there are few published epidemiological data regarding invasive pneumococcal disease (IPD) in South East Asian countries. Existing data regarding the epidemiology of S. pneumoniae in Singapore have focussed on disease presentation (Low et al., 2007) or antibiotic resistance (Song et al., 2004a, b). Two previous studies have investigated serotype distribution among Singaporean childhood IPD isolates from 1997-1999 (n5180) and 1997-2004 (n5147) (Chong et al., 2008;Soh et al., 2000).Baseline data regarding the serotype prevalence of IPD are essential to inform policy around the use of pneumococcal conjugate vaccines (PCVs) in Singapore. PCV7 has been available on a demand basis in Singapore since October 2005 but was only incorporated into the national childhood vaccination schedule in November 2009 (Vasoo et al., 2010).Information that aids in understanding the genetic background of pneumococci associated with IPD is also important; the invasive potential of individual clones to succeed and spread geographically is associated with genotype as well as serotype (Hanage et al., 2005; Henriques-Normark et al., 2008;Sandgren et al., 2004). Clonal expansion has been shown to result in notable changes in circulating pneumococcal populations even in the absence of vaccine pressure.To our knowledge, no published study has used multilocus sequence typing (MLST) to characterize Singaporean pneumococcal disease isolates. The objective of this study was to characterize pneumococci isolated from IPD in Singaporean children using serotyping and MLST and compare these data to data from elsewh...

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“…The predominant serotypes observed in the present study comprised genetically diverse clones as demonstrated by previous studies in the United Kingdom [14,15]. Within a single serotype, genetic variability may have arisen largely by divergence from ancestral clones through evolutionary biology.…”

Section: Resultsmentioning

confidence: 71%

Genetic characteristics of pneumococcal disease in elderly patients before introducing the pneumococcal conjugate vaccine

et al. 2009

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Streptococcus pneumoniae strains causing invasive pneumococcal disease (IPD) in the elderly population of England and Wales during the winter of 2003/2004 (1 November 2003 to 30 April 2004) were characterized by serotyping and genotyping in order to determine their population structure in the elderly. Serotyping and multilocus sequence typing (MLST) were carried out on 542 invasive isolates referred to the Respiratory and Systemic Infection Laboratory. Pneumococci were distributed among 32 serotypes and 144 MLST sequence types. A high genetic diversity was observed within the major serotypes. Genetic relatedness varied with regard to serotype. Isolates within serotypes 3, 7F and 8 were the most genetically related whereas serotypes 6A and 19F comprised isolates originating from unrelated ancestors. There was indirect evidence that some pneumococci were derived from clones that had undergone capsular switching in the past. Interestingly one case of IPD was caused by a pneumococcus originating from a clone that had undergone capsular switching from serotype 18C, a serotype included in 7-valent pneumococcal conjugate vaccine (PCV) to serotype 1 (serotype not included in PCV) suggesting that virulent clones with the potential ability to evade PCV existed in the pneumococcal population prior to the routine introduction of this vaccine. Isolates from 28 cases of apparent 23-valent pneumococcal polysaccharide vaccine (PPV) failure were included but there was no evidence of the emergence of particular clones associated with vaccine failures. Longitudinal studies based on serotypic and genetic characterization of pneumococci are fundamental to understanding the impact of both PPV and PCV on the genetic structure of pneumococcal populations.

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Pneumococci causing invasive disease in children prior to the introduction of pneumococcal conjugate vaccine in Scotland

Cited by 9 publications

References 35 publications

Serotypes and genotypes of Streptococcus pneumoniae isolates from Trinidad and Tobago

Serotypes and genotypes of Streptococcus pneumoniae isolates from Trinidad and Tobago

Molecular analysis of Streptococcus pneumoniae clones causing invasive disease in children in Singapore

Genetic characteristics of pneumococcal disease in elderly patients before introducing the pneumococcal conjugate vaccine

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