Synergism of Staphylococcus aureus colonization and allergic reaction in the nasal cavity in mice

Nasal carriage of Staphylococcus aureus in children with grass pollen‐induced allergic rhinitis and the effect of polyvalent mechanical bacterial lysate immunostimulation on carriage status: A randomized controlled trial

Background

Numerous studies indicate that Staphylococcus aureus (S. aureus) colonizing the nasal cavity plays a role in the pathogenesis of allergic rhinitis (AR). This bacterium is able to produce a variety of toxins with superantigenic properties that can exacerbate allergic inflammation.

Objective

The objective of the study was to evaluate the ability of polyvalent mechanical bacterial lysate (PMBL) to eliminate S. aureus nasal carriage in children with grass pollen‐induced AR.

Methods

This randomized, double‐blind, placebo‐controlled study included 80 children aged 5–17 years with seasonal AR (SAR). At the randomization visit and after 12 weeks of the study, a swab was taken from the region of the middle nasal meatus. Standard microbiology culture and identification techniques were used to analyze the swab contents.

Results

Nasal colonization by S. aureus was confirmed in 29 children (42%), with Moraxella catarrhalis in three participants (4.4%). Physiological flora was detected in 37 children. No statistically significant differences were observed between the two measurement points in both the PMBL and placebo groups with respect to the number of patients whose nasal swab cultures showed a growth of S. aureus (p = 1). Both groups also showed no significant changes in the mean number of S. aureus colonies in nasal swab cultures taken at baseline and after 12 weeks of the study (PMBL group p = .41; placebo group p = .16).

Conclusion

Almost every second child with SAR is S. aureus nasal carrier. Sublingual administration of PMBL in children with grass pollen‐induced AR did not affect S. aureus nasal colonization. Therefore, PMBL should not be used for the eradication of S. aureus from the nasal cavity.

Nasal saline irrigation with or without systemic antibiotics in treatment of children with acute rhinosinusitis

OBJECTIVES

Acute rhinosinusitis (ARS) is a common pediatric problem. Our aim was to determine the efficacy of normal nasal saline irrigation (NSI) with or without amoxicillin in treatment of acute rhinosinusitis (ARS) in children.

METHODS

It is a prospective randomized, blind placebo-controlled trial. Children with uncomplicated ARS were recruited. One group received (amoxacillin 100mg/kg/day) and 0.9% NSI. The second group received placebo and 0.9% NSI. The primary outcome was the effect of treatment on clinical response. Secondary outcomes included: Rating of Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ), middle meatus (MM) bacteriological and cytological cellular responses and adverse effects.

RESULTS

Sixty two patients with ARS were eligible for the study. In amoxicillin group (31 patients); clinical cure was observed in 26 (83.9%) in comparison to 22 (71%) patients in NSI without antibiotics group (31 patients) (p=0.22). No differences between both groups in the reported nasal symptom scores and total symptoms scores improvements at day 7 (p=0.09 and 0.65) and day 14 (p=0.29 and 0.14), respectively. The mean total PRQLQ values had no differences between both groups after the 2 weeks of treatment (p=0.06). At day 7, MM neutrophils reduced significantly in amoxicillin group in comparison to placebo group (p=0.004). At day 14, the MM cytological content had no differences between both groups (p=0.07). Normal NSI with placebo has less reported adverse effects than amoxicillin and nasal saline irrigations (p=0.005).

CONCLUSIONS

NSI can be used alone with the same clinical, bacteriological and cytological cellular changes efficacy and with higher safety profile than amoxicillin after 14 days of treatment in uncomplicated clinically diagnosed ARS in children.

Plasmacytoid Dendritic Cells: Neglected Regulators of the Immune Response to Staphylococcus aureus

Plasmacytoid dendritic cells (pDC) are a rare subset of leukocytes equipped with Fcγ and Fcε receptors, which exert contrary effects on sensing of microbial nucleic acids by endosomal Toll-like receptors. In this article, we explain how pDC contribute to the immune response to Staphylococcus aureus. Under normal circumstances the pDC participates in the memory response to the pathogen: pDC activation is initiated by uptake of staphylococcal immune complexes with IgG or IgE. However, protein A-expressing S. aureus strains additionally trigger pDC activation in the absence of immunoglobulin. In this context, staphylococci exploit the pDC to induce antigen-independent differentiation of IL-10 producing plasmablasts, an elegant means to propagate immune evasion. We further discuss the role of type I interferons in infection with S. aureus and the implications of these findings for the development of immune based therapies and vaccination.