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Maria da Gloria Carvalho,
Geoffrey Jagero,
Godfrey M. Bigogo,
Muthoni Junghae,
Fabiana C. Pimenta,
Iaci Moura, Alexis Roundtree,
Zhongya Li,
Laura Conklin,
Daniel R. Feikin,
Robert F. Breiman,
Cynthia G. Whitney1 and Bernard Beall
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ABSTRACT: Monitoring pneumococcal carriage serotype distributions is increasingly used to study pneumococcal biology, disease epidemiology, and vaccine impact
Journal of clinical microbiology. 02/2013; 2012 Sep;50(9):3146-7.
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Iaci Moura,
Muthoni Junghae,
Laura Conklin,
Cynthia G Whitney,
Fabiana C Pimenta, Robert F Breiman,
Maria da Gloria Carvalho,
Bernard Beall,
Alexis Roundtree,
Godfrey M Bigogo,
Zhongya Li,
Daniel R Feikin
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ABSTRACT: We developed and validated a real-time PCR assay consisting of 7 triplexed reactions to identify 11 individual serotypes plus 10 small serogroups representing the majority of disease-causing isolates of Streptococcus pneumoniae. This assay targets the 13 serotypes included within the 13-valent conjugate vaccine and 8 additional key serotypes or serogroups. Advantages over other serotyping assays are described. The assay will be expanded to 40 serotypes/serogroups. We will provide periodic updates at our protocol web site.
Journal of clinical microbiology 12/2012; · 4.16 Impact Factor
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Maria da Gloria Carvalho,
Godfrey M Bigogo,
Muthoni Junghae,
Fabiana C Pimenta,
Iaci Moura, Alexis Roundtree,
Zhongya Li,
Laura Conklin,
Daniel R Feikin,
Robert F Breiman,
Cynthia G Whitney,
Bernard Beall
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ABSTRACT: Monitoring pneumococcal carriage serotype distributions is increasingly used to study pneumococcal biology, disease epidemiology, and vaccine impact.…
Journal of clinical microbiology 07/2012; 50(9):3146-7. · 4.16 Impact Factor
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Eugene V Millar,
Fabiana C Pimenta, Alexis Roundtree,
Delois Jackson,
Maria da Gloria Carvalho,
Mindy J Perilla,
Raymond Reid,
Mathuram Santosham,
Cynthia G Whitney,
Bernard W Beall,
Katherine L O'Brien
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ABSTRACT: A second-generation 13-valent pneumococcal conjugate vaccine, PCV13, was recently licensed. Although PCV13 includes serotype 6A, the usefulness of that antigen may be limited by the emergence of a new serotype, 6C, which was identified among isolates initially characterized (Quellung reaction) as serotype 6A. The epidemiology of serotype 6C prior to and after 7-valent PCV (PCV7) introduction is incompletely understood.
We analyzed conventionally serotyped 6A (CS6A) pneumococci from invasive disease case patients of all ages and carriage isolates from children and adults obtained in population-based studies among Navajo and White Mountain Apache communities during 1994-2009. Samples were tested by triplex polymerase chain reaction to resolve serotypes 6C and 6A.
A total of 74 invasive CS6A episodes occurred. All were retyped by polymerase chain reaction; 40 (54.1%) were serotype 6C. The mean annual incidence of serotype 6C invasive disease was 0.3 (95% confidence interval, 0.03-0.9), 0.7 (95% confidence interval, 0.2-1.3), and 1.5 (95% confidence interval, 1.0-2.1) cases per 100,000 population in the years prior to the PCV7 efficacy trial, during the time the PCV7 trial was conducted, and following PCV7 introduction and routine use, respectively (P = .01). In the routine vaccination era, 76% of invasive CS6As were serotype 6C; nearly all cases occurred in adults. The proportion of serotype 6C among CS6A carriage isolates increased from 42% to 61% to 94% in the prevaccine, early vaccine, and routine vaccination eras, respectively.
In the PCV7 routine use era, virtually all serogroup 6 invasive pneumococcal disease and carriage strains among Navajo and White Mountain Apache communities are 6C. Monitoring and evaluation of this and other emerging serotypes among invasive disease and carriage isolates is warranted.
Clinical Infectious Diseases 10/2010; 51(11):1258-65. · 9.15 Impact Factor
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ABSTRACT: The measurement of pneumococcal carriage in the nasopharyngeal reservoir is subject to potential confounders that include low-density and multiple-strain colonization. To compare different methodologies, we picked a random sampling of 100 nasopharyngeal specimens recovered from infants less than 2 years of age who were previously assessed for pneumococcal carriage and serotypes by a conventional method that used direct plating from the transport/storage medium (50 specimens were culture negative and 50 specimens were culture positive for pneumococci). We used a broth enrichment approach and a conventional PCR approach (with and without broth enrichment) to determine pneumococcal carriage and serotypes, and the results were compared to the initial conventional culture-based results. Additionally, we used a lytA-targeted real-time PCR for pneumococcal detection. Broth enrichment for both the culture-based and the PCR-based methods enhanced the isolation of pneumococci and detection of serotype diversity, with the most effective serotype deduction method being one that used broth enrichment prior to sequential multiplex PCR. Similarly, we also found that broth enrichment followed by the lytA-specific real-time PCR was the most sensitive for the detection of apparent pneumococcal carriage. The broth enrichment, conventional multiplex PCR, and real-time PCR approaches used in this study were effective in detecting pneumococcal carriage in the 50 specimens that were negative by conventional direct plating from transport medium (range of numbers of positive specimens, 8/50 to 22/50 [16 to 44%]), and the three different serotyping approaches that used broth enrichment increased the number of serotype identifications from the 100 specimens (12 to 29 additional serotype identifications to be positive). A PCR-based approach that employed a broth enrichment step appeared to best enhance the detection of mixed serotypes and low-density pneumococcal carriage.
Journal of clinical microbiology 03/2010; 48(5):1611-8. · 4.16 Impact Factor
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ABSTRACT: Determination of the DNA sequences corresponding to all 91 pneumococcal capsular biosynthetic (cps) loci (1, 3, 6, 9) has allowed serotype deduction from pneumococcal isolates and clinical specimens using conventional PCR assays (2, 4, 7, 8, 10). ...
Journal of clinical microbiology 06/2009; 47(7):2353-4. · 4.16 Impact Factor
