Probiotics and carriage of Streptococcus pneumoniae serotypes in Danish children, a double-blind randomized controlled trial

Abstract

This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8–19 months and assessed the effect of the probiotics Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis on the pneumococcal carriage during daycare enrolment. Potential risk factors of pneumococcal carriage were analysed and the carriage study was compared with registered invasive pneumococcal disease (IPD) data. This study is a part of the ProbiComp study, which was a double-blind, randomized controlled trial, including 290 children allocated to probiotics or placebo for 6 months and recruited during two autumn seasons (2014/2015). Pneumococci were identified by optochin sensitivity, bile solubility, α-hemolysis and/or capsular reaction. Serotyping was performed by latex agglutination kit and Quellung reaction. The carriage rate of S. pneumoniae was 26.0% at baseline and 67.4% at the end of intervention. No significant difference was observed between the placebo group and the probiotics group (p = 0.508). Children aged 8–19 months were carriers of non-pneumococcal vaccine serotypes causing IPD in children aged 0–4 years. However, serotypes causing most IPD cases in Danish elderly were either not found or found with low prevalence suggesting that children are not the main reservoir of those serotypes and other age groups need to be considered as carriers.

Pneumococcal carriage among children under five in Accra, Ghana, five years after the introduction of pneumococcal conjugate vaccine

“…Streptococcus pneumoniae (pneumococcus) is considered the leading pathogen associated with community-acquired pneumonia, otitis media and meningitis [1]. Pneumococcal appearance in humans can be divided into two phases, carriage and the disease phase, where the carriage of S. pneumoniae is generally described as the prerequisite for developing pneumococcal infections, and often young children are considered to act as reservoirs [2, 3]. Pneumococcal infections have attracted global public health attention due to the high burden of disease and associated mortality, particularly among children under five and adults > 64 years in resource poor countries [1, 4, 5].…”

Factors influencing PCV13 specific antibody response in Danish children starting in day care

“…In a previous study 10 we found that children living with siblings had a significant higher carriage rate of S. pneumoniae compared to only children. In this study, we assessed the PCV13 antibody response in children with and without siblings as novel information and found that at baseline there was no significant statistical difference in the PCV13 antibody response when compared children with and without siblings (p = 0.157), but having siblings increased the PCV13 antibody response (µg/mL) at the end of study (p = 0.0135) (Fig.…”

“…Previous studies show no statistical significance between the probiotics group and the placebo group when comparing carriage rate of pneumococcal serotypes and no significant difference in antibody response to PCV13 8,10 . Furthermore, no significant differences between the groups were seen in terms of gender, siblings, breastfeeding, indoor pets, health status since birth, smoking in the household, age or compliance 18 , thus the two groups were compiled for analyses in this study (Table 1).…”

“…Our previous study 10 showed a statistically significant difference between non-carriers and carriers in terms of living with or without siblings at baseline, showing a higher risk of carrying pneumococcal serotypes before day care attendance if the child has at least one older sibling. This study on the other hand shows that the PCV13 antibody response was not affected by the number of siblings at baseline, but a higher PCV13 antibody response was seen in children with siblings at the end of study.…”

“…Briefly, minitip flocked swabs (FLOQSwabs TM , Copan, Italy) were inserted Identification of pneumococcal serotypes. The identification of pneumococcal serotypes was performed as previously described 9,10 Briefly, inoculated serum-ox broth was incubated overnight at 37 °C in 5% CO 2 before plating on 10% horse blood agar plates to increase sensitivity 9 . Pneumococcal serotypes were identified based on optochin sensitivity, bile solubility, α-hemolysis, pneumotest latex agglutination kit (SSI Diagnostica, Hillerød, Denmark) performed on the serum-broth and Quellung reaction (Neufeld test) using serotype specific antisera (SSI Diagnostica, Hillerød, Denmark).…”