scholarly journals PCR and Culture Analysis of Streptococcus pneumoniae Nasopharyngeal Carriage in Healthy Children

2021 ◽  
Vol 9 (10) ◽  
pp. 2116
Author(s):  
Leah Ricketson ◽  
Ravinder Lidder ◽  
Robyn Thorington ◽  
Irene Martin ◽  
Otto Vanderkooi ◽  
...  

Invasive Streptococcus pneumoniae disease is preceded by asymptomatic nasopharyngeal carriage. Measuring carriage in healthy populations provides data on what serotypes are present in communities, which is of interest in the era of polyvalent pneumococcal conjugate vaccines. Nasopharyngeal swabs from a survey of 682 and 800 healthy children in 2016 and 2018, respectively, were analyzed by culture and Quellung reaction to determine rates of carriage and serotypes. All swabs from 2016 and 300 randomly selected swabs from 2018 were then analyzed using real-time semi-quantitative PCR (qPCR) to detect S. pneumoniae gene targets lytA, piaA, and SP2020 and determine serotype. There were 71 (10.4%) and 68 (8.5%) culture positive samples in 2016 and 2018, respectively. All of these were also positive by qPCR except one that was equivocal. In total, 46.0% of 2016 swabs were positive by qPCR. In 2018, results from the selected sample extrapolated to the complete sample showed 49.0% positive by qPCR. PCV13 serotypes were detected in 29.3% and 21.7% of S. pneumoniae qPCR positive samples from 2016 and 2018, respectively; compared with only 8.4% and 6.0% PCV13 serotypes detected by Quellung reaction in culture positive samples. Compared with culture, qPCR detected S. pneumoniae more frequently. Further, qPCR serotyping detected PCV13 serotypes in a larger proportion of samples than culture and Quellung reaction did, showing that, despite established universal childhood PCV13 immunization, vaccine serotypes can still be detected in a large proportion of young children.

2021 ◽  
Author(s):  
Andrea Gori ◽  
Uri Obolski ◽  
Todd D Swarthout ◽  
Jose Lourenco ◽  
Caroline M Weight ◽  
...  

Streptococcus pneumoniae accounts for at least 300,000 deaths from pneumonia, septicaemia and meningitis among children under 5-years-old worldwide. Protein-polysaccharide conjugate vaccines (PCVs) are highly effective at reducing vaccine serotype disease but emergence of non-vaccine serotypes and persistent nasopharyngeal carriage threaten to undermine this success. Here, we address the hypothesis that following vaccine introduction in high disease and carriage burden settings, adapted pneumococcal genotypes emerge with the potential to facilitate vaccine escape. We show that beyond serotype replacement, there are marked changes in S. pneumoniae carriage population genetics amongst 2804 isolates sampled 4-8 years after the 2011 introduction of PCV-13 in urban Malawi. These changes are characterised by metabolic genotypes with distinct virulence and antimicrobial resistance (AMR) profiles. This included exclusive genes responsible for metabolism and carbohydrate transport, and toxin-antitoxin systems located in an integrative-conjugative region suggestive of horizontal gene transfer. These emergent genotypes were found to have differential growth, haemolytic, or epithelial adhesion/invasion traits that may confer advantage in the nasopharyngeal niche. Together these data show that in the context of PCV13 introduction in a high burden population, there has been a shift in the pneumococcal population dynamics with the emergence of genotypes that have undergone multiple adaptations extending beyond simple serotype replacement, a process that could further undermine vaccine control and promote the spread of AMR.


2011 ◽  
Vol 5 (S1) ◽  
Author(s):  
Julie Scotet ◽  
Francine Baumann ◽  
Myrielle Dupont-Rouzeyrol ◽  
Catherine Grangeon ◽  
Shahin Oftadeh ◽  
...  

Vaccine ◽  
2021 ◽  
Vol 39 (15) ◽  
pp. 2041-2047
Author(s):  
Mehmet Ceyhan ◽  
Eda Karadag-Oncel ◽  
Gulsen Hascelik ◽  
Gulnihan Ustundag ◽  
Venhar Gurbuz ◽  
...  

2009 ◽  
Vol 29 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Hyojin Chae ◽  
Je-Hoon Lee ◽  
Jihyang Lim ◽  
Seung-Won Jung ◽  
Myungshin Kim ◽  
...  

Vaccines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Santiago Alfayate Miguélez ◽  
Genoveva Yague Guirao ◽  
Ana Menasalvas Ruíz ◽  
Manuel Sanchez-Solís ◽  
Mirian Domenech Lucas ◽  
...  

Background: An epidemiological study of Streptococcus pneumoniae nasopharyngeal carriage in healthy children was carried out five years after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13). Objectives: Study the impact of pediatric vaccination with PCV13, and other associated epidemiological factors on the status of nasopharyngeal carriage, the circulating pneumococcal serotypes, and the antibiotic susceptibility to more frequently used antibiotics. Methods: A multi-center study was carried out in Primary Health Care, which included 1821 healthy children aged 1 to 4 years old. All isolates were sent to the Spanish Pneumococcal Reference Laboratory for serotyping and antimicrobial susceptibility testing. Results: At least one dose of PCV13 had been received by 71.9% of children and carriage pneumococcal prevalence was 19.7%. The proportion of PCV13 serotypes was low (14.4%), with an observed predominance of non-vaccine serotypes, 23B, 11A, 10A, 35B/F, and 23A were the five most frequent. A high rate of resistance to penicillin, erythromycin, and trimethoprim sulfamethoxazole was found. Conclusions: A low proportion of PCV13 serotypes were detected, confirming the impact of pediatric vaccination for reducing the serotypes vaccine carriage. High resistance rates to clinically important antibiotics were observed.


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