Pneumococcal nasopharyngeal carriage among children in Brazil prior to the introduction of the 10-valent conjugate vaccine: a culture- and PCR-based survey

Abstract

We performed two different approaches (broth enrichment step prior to culture (BEC) and PCR (BEPCR)) for detecting Streptococcus pneumoniae from nasopharyngeal specimens collected from 242 children aged <6 years attending one hospital (n = 140) and one childcare centre (n = 102) in a major urban area in Brazil. These specimens were collected immediately before the introduction of the 10-valent pneumococcal conjugate vaccine (PCV10) and the 13-valent vaccine (PCV13) for routine use in Brazil. Results were compared with previous findings obtained with direct culture (DC) on a selective medium. Colonisation prevalence was 58·3% (n = 141), being higher among children attending the childcare centre (62·7% vs. 55%). The culture-based methods (DC and BEC) enabled the detection of S. pneumoniae in 119 (49·2%) and 115 (47·5%) children, respectively. The PCR-based method (BEPCR) was more sensitive and 137 (56·6%) carriers were identified. Twenty-six serogroups/serotypes were identified, predominantly 6B, 19F, 14, 6A, 15C and 23F. Multiple colonisation was observed in 13 (5·4%) children. The estimated serotypes coverage of available PCVs was 40·4% for the 10-valent (included in the Brazilian immunisation programme) and 55·8% for the 13-valent (only available in private clinics). The use of robust approaches to obtain a more realistic insight about the asymptomatic carrier status is of paramount importance to estimate and assess the impact of vaccine implementation. The combination between culture-based and molecular methods constitutes a suitable strategy.

10-valent pneumococcal conjugate vaccine (PCV10) decreases metabolic activity but not nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae

“…Therefore, the differences in the vaccination schemes did not significantly affect the outcome variables from this study. Finally, although carriage rates described herein were extremely high for some pathogenic bacteria, high carriage rates for the studied bacteria have been described elsewhere [23][24][25]. Furthermore, we applied a highly sensitive method (and still specific, as shown in Fig.…”

Synergistic antibacterial activity of EGCGcombined with imipenem against planktonic Carbapenem-resistant Klebsiella pneumoniae and the evaluation of independent antibiofilm activity of EGCG

“…Each point represented the mean ± SD of the OD590 values performed in triplicate. The 12 parallel plates were finished incubation at 37℃ for 4,8,12,16,20,24,28,32,36,40,44 and 48hr, respectively. The degree of the currently formed biofilm were quantified by Crystal Violet assay.…”

“…Total DNA of the CRKP was extracted by the boiling method to recover supernatant according to Rodrigues HG et al (24). PCR were performed in a final volume of 25 μL comprising 0.5 μL of extracted DNA as the template, 0.5 μL of primer-F, 0.5 μL of primer-R, 0.5 μL of Taq DNA polymerase (TaKaRa, Dalian, China), 2 μL of dNTP (200 μM), 2.5 μL of 10× PCR buffer and 18.5 μl of sterile double-distilled water.…”

A rapid and sensitive recombinase aided amplification assay incorporating competitive internal control to detect Bordetella pertussis using the DNA obtained by boiling

“…The DNA was eluted in 100 mL of elution buffer and stored at À80 C until needed. In parallel, the clinical samples were heated at 100 C for 15 min, followed by centrifugation (14.000 rpm/1 min) to recover supernatant and were cooled to room temperature until use (Rodrigues et al, 2017).…”