Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Harker-Jones M[original query] |
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Streptococcus pneumoniae serotype 3 population structure in the era of conjugate vaccines, 2001-2018
Cella E , Sutcliffe CG , Grant LR , Tso C , Weatherholtz RC , Littlepage S , Becenti L , Jubair M , Simons BC , Harker-Jones M , Reid R , Yazzie D , Santosham M , O'Brien KL , Hammitt LL , Azarian T . Microb Genom 2024 10 (3) Background. Despite use of highly effective conjugate vaccines, invasive pneumococcal disease (IPD) remains a leading cause of morbidity and mortality and disproportionately affects Indigenous populations. Although included in the 13-valent pneumococcal conjugate vaccine (PCV13), which was introduced in 2010, serotype 3 continues to cause disease among Indigenous communities in the Southwest USA. In the Navajo Nation, serotype 3 IPD incidence increased among adults (3.8/100 000 in 2001-2009 and 6.2/100 000 in 2011-2019); in children the disease persisted although the rates dropped from 5.8/100 000 to 2.3/100 000.Methods. We analysed the genomic epidemiology of serotype 3 isolates collected from 129 adults and 63 children with pneumococcal carriage (n=61) or IPD (n=131) from 2001 to 2018 of the Navajo Nation. Using whole-genome sequencing data, we determined clade membership and assessed changes in serotype 3 population structure over time.Results. The serotype 3 population structure was characterized by three dominant subpopulations: clade II (n=90, 46.9 %) and clade Iα (n=59, 30.7 %), which fall into Clonal Complex (CC) 180, and a non-CC180 clade (n=43, 22.4 %). The proportion of clade II-associated IPD cases increased significantly from 2001 to 2010 to 2011-2018 among adults (23.1-71.8 %; P<0.001) but not in children (27.3-33.3 %; P=0.84). Over the same period, the proportion of clade II-associated carriage increased; this was statistically significant among children (23.3-52.6 %; P=0.04) but not adults (0-50.0 %, P=0.08).Conclusions. In this setting with persistent serotype 3 IPD and carriage, clade II has increased since 2010. Genomic changes may be contributing to the observed trends in serotype 3 carriage and disease over time. |
Population structure of invasive Streptococcus pneumoniae isolates among Alaskan children in the conjugate vaccine era, 2001 to 2013.
Miernyk KM , Bulkow LR , Case SL , Zulz T , Bruce MG , Harker-Jones M , Hurlburt DA , Hennessy TW , Rudolph KM . Diagn Microbiol Infect Dis 2016 86 (2) 224-30 Here we describe the relationships between serotypes, genotypes, and antimicrobial susceptibility among isolates causing invasive pneumococcal disease in Alaskan children during the pneumococcal conjugate vaccine (PCV) era. From 2001 to 2013 we received 271 isolates representing 33 serotypes. The most common serotypes were 19A (29.5%, n= 80), 7F (12.5%, n= 34), 15B/C (6.3%, n= 17), and 22F (4.8%, n= 13). Multilocus sequence typing identified 11 clonal complexes (CC) and 45 singletons. Five CCs accounted for 52% (141/271) of the total: CC199 (21% [n= 57], serotypes 19A, 15B/C), CC191 (12.2% [n= 33], serotype 7F), CC172 (10.3% [n= 28], serotypes 19A, 23A, 23B), CC433 (4.4% [n= 12], serotype 22F), and CC100 (4.4% [n= 12], serotype 33F). The proportion of isolates nonsusceptible to erythromycin and tetracycline increased after 13-valent PCV use (14% [n= 30] versus 29% [n= 14]; P= 0.010) and (4% [n= 9] versus 22% [n= 11]; P< 0.001), respectively. The genetic diversity also increased after 13-valent PCV use (Simpson's diversity index =0.95 versus 0.91; P= 0.022). |
Molecular resistance mechanisms of macrolide-resistant invasive Streptococcus pneumoniae isolates from Alaska, 1986 to 2010.
Rudolph K , Bulkow L , Bruce M , Zulz T , Reasonover A , Harker-Jones M , Hurlburt D , Hennessy T . Antimicrob Agents Chemother 2013 57 (11) 5415-22 The rapid emergence of antibiotic-resistant pneumococcal strains has reduced treatment options. The aim of this study was to determine antimicrobial susceptibilities, serotype distributions, and molecular resistance mechanisms among macrolide-resistant invasive pneumococcal isolates in Alaska from 1986 to 2010. We identified cases of invasive pneumococcal disease in Alaska from 1986 to 2010 through statewide population-based laboratory surveillance. All invasive pneumococcal isolates submitted to the Arctic Investigations Program laboratory were confirmed by standard microbiological methods and serotyped by slide agglutination and the Quellung reaction. MICs were determined by the broth microdilution method, and macrolide-resistant genotypes were determined by multiplex PCR. Among 2,923 invasive pneumococcal isolates recovered from 1986 to 2010, 270 (9.2%) were nonsusceptible to erythromycin; 177 (66%) erythromycin-nonsusceptible isolates demonstrated coresistance to penicillin, and 167 (62%) were multidrug resistant. The most frequent serotypes among the macrolide-resistant isolates were serotypes 6B (23.3%), 14 (20.7%), 19A (16.7%), 9V (8.9%), 19F (6.3%), 6A (5.6%), and 23F (4.8%). mef and erm(B) genes were detected in 207 (77%) and 32 (12%) of the isolates, respectively. Nineteen (7%) of the erythromycin-nonsusceptible isolates contained both mef and erm(B) genotypes; 15 were of serotype 19A. There was significant year-to-year variation in the proportion of isolates that were nonsusceptible to erythromycin (P < 0.001). Macrolide resistance among pneumococcal isolates from Alaska is mediated predominantly by mef genes, and this has not changed significantly over time. However, there was a statistically significant increase in the proportion of isolates that possess both erm(B) and mef, primarily due to serotype 19A isolates. |
Epidemiology of pneumococcal serotype 6A and 6C among invasive and carriage isolates from Alaska, 1986-2009.
Rudolph K , Bruce M , Bruden D , Zulz T , Wenger J , Reasonover A , Harker-Jones M , Hurlburt D , Hennessy T . Diagn Microbiol Infect Dis 2012 75 (3) 271-6 We investigated serotype 6A/6C invasive pneumococcal disease (IPD) incidence, genetic diversity, and carriage before and after 7-valent pneumococcal conjugate vaccine (PCV7) introduction in Alaska. IPD cases (1986-2009) were identified through population-based laboratory surveillance. Isolates were initially serotyped by conventional methods, and 6C isolates were differentiated from 6A by polymerase chain reaction. Among invasive and carriage isolates initially typed as 6A, 35% and 50% were identified as 6C, respectively. IPD rates caused by serotype 6A or 6C among children <5 years did not change from the pre- to post-PCV7 period (P = 0.71 and P = 0.09, respectively). Multilocus sequence typing of IPD isolates revealed 28 sequence types. The proportion of serotype 6A carriage isolates decreased from 7.4% pre-PCV7 to 1.8% (P < 0.001) during 2008-2009; the proportion of serotype 6C carriage isolates increased from 3.0% to 8.4% (P = 0.004) among children <5 years. Continued surveillance is warranted to monitor changes in serotype distribution and prevalence. |
Serotyping of Streptococcus pneumoniae isolates from nasopharyngeal samples: use of an algorithm combining microbiologic, serologic, and sequential multiplex PCR techniques.
Miernyk K , Debyle C , Harker-Jones M , Hummel KB , Hennessy T , Wenger J , Rudolph K . J Clin Microbiol 2011 49 (9) 3209-14 We evaluated nasopharyngeal carriage of Streptococcus pneumoniae (pneumococci) in nine Alaskan communities and used an algorithm combining microbiologic, serologic, and sequential multiplex PCR (MP-PCR) techniques to serotype the isolates. After microbiological identification as pneumococci, isolates (n = 1,135) were serotyped using latex agglutination and Quellung tests (LA/Q) as well as a series of six sequential MP-PCR assays. Results from the two methods agreed for 94% (1,064/1,135) of samples. Eighty-six percent (61/71) of the discordant results were resolved. Discordant results occurred because (i) the MP-PCR gel was misread (31/61 [51%]), (ii) the LA/Q agglutination was misinterpreted (13/61 [21%]), (iii) two serotypes or sets of serotypes were identified by MP-PCR and only one of the two was identified by LA/Q (9/61 [15%]), (iv) different serotypes or sets of serotypes were identified by LA/Q and MP-PCR and both were correct (7/61 [11%]), and (v) the capsular polysaccharide locus (cps) did not amplify during the initial MP-PCR but was present upon retesting (1/61 [2%]). Overall, isolation of pneumococci followed by MP-PCR quickly and accurately identified pneumococcal serotypes in >97% of samples and made available isolates for additional tests such as antimicrobial susceptibility. Misinterpretation of the MP-PCR gel was identified as the main source of discordance. Increasing the number of MP-PCRs from six to seven and reducing the number of serotypes in each reaction may reduce this error. This method may be of use to laboratories characterizing large numbers of S. pneumoniae samples, especially when antimicrobial susceptibility data are needed. |
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