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Pneumococcal colonization among tracheostomy tube dependent children.

ABSTRACT: Streptococcus pneumoniae colonization is a precursor to pneumococcal disease. Although children with a tracheostomy have an increased risk of pneumococcal pneumonia, the pneumococci colonizing their lower airways remain largely uncharacterized. We sought to compare lower respiratory tract isolates colonizing tracheostomy patients and a convenience sample of isolates from individuals intubated for acute conditions. We collected pneumococcal isolates from the lower respiratory tract of 27 patients with a tracheostomy and 42 patients intubated for acute conditions. We compared the penicillin susceptibility, rates of co-colonization, genetic background, and serotype of isolates colonizing these patient populations. Isolates from both groups showed high genetic diversity. Forty multi-locus sequence types and 20 serotypes were identified. There was no significant difference in serotype distribution, co-colonization rates, vaccine coverage, or non-susceptibility to penicillin among pneumococcal isolates from the two groups. Colonization of the lower airways with non-vaccine serotypes 15B/C, 23B and 35B was noted for the first time in patients with tracheostomies and supports recently observed increases in nasopharyngeal colonization and disease due to these serotypes.

SUBMITTER: Erdem G

PROVIDER: S-EPMC6195293 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Pneumococcal colonization among tracheostomy tube dependent children.

Erdem Guliz G Singh Anirudh K AK Brusnahan Anthony J AJ Moore Amber N AN Barson William J WJ Leber Amy A Vidal Jorge E JE Atici Serkan S King Samantha J SJ

PloS one 20181019 10

Streptococcus pneumoniae colonization is a precursor to pneumococcal disease. Although children with a tracheostomy have an increased risk of pneumococcal pneumonia, the pneumococci colonizing their lower airways remain largely uncharacterized. We sought to compare lower respiratory tract isolates colonizing tracheostomy patients and a convenience sample of isolates from individuals intubated for acute conditions. We collected pneumococcal isolates from the lower respiratory tract of 27 patients ...[more]

PMID: 30339709

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Project description:Pneumococcal conjugate vaccine (PCV) immunization of children induces shifts in colonizing pneumococcal serotypes. This study evaluated the effect of infant vaccination with 7-valent PCV (PCV7) on vaccine serotype (VT) colonization and whether the increase in nonvaccine serotype (NVT) was due to either unmasking of previously low-density-colonizing serotypes or increase in acquisition of NVT. A multiplex quantitative PCR (qPCR) was used to evaluate VT and NVT nasopharyngeal colonization in archived swabs of PCV-vaccinated and PCV-unvaccinated African children at 9 and 15 to 16 months of age. Molecular qPCR clearly identified the vaccine effect typified by a decrease in VT colonization and an increase in NVT colonization. Serotype 19A was primarily responsible for the higher NVT carriage among PCV vaccinees at 9 months of age (53.4% difference; P = 0.021) and 16 months of age (70.7% difference; P < 0.001). Furthermore, the density of serotype 19A colonization was higher in PCV-vaccinated groups than in PCV-unvaccinated groups (3.76 versus 2.83 CFU/ml [P = 0.046], respectively, and 4.15 versus 3.04 CFU/ml [P = 0.013], respectively) at 9 and 16 months of age, respectively. Furthermore, serotype 19A was also more commonly reported as a primary isolate (by having the highest density among other cocolonizing serotypes identified in the sample) in PCV7-vaccinated children, while being equally a primary (46.2%) or nonprimary (53.8%) isolate in PCV-unvaccinated children. Molecular qPCR showed both serotype replacement and unmasking to be the cause for the increase in NVT colonization in PCV7-vaccinated children, as some serotypes were associated with an absolute increase in colonization (replacement), while others were associated with an increase in detection (unmasking). IMPORTANCE This study focused on evaluating the effect of infant vaccination with 7-valent pneumococcal conjugate vaccine (PCV7), using a multiplex qPCR method, on the density of serotype-specific nasopharyngeal colonization in order to delineate the relative role of serotype replacement versus unmasking as the cause for the increase in nonvaccine serotype colonization in PCV7-vaccinated children. This is pertinent in the context of the ongoing deployment of PCV immunization in children, with surveillance of colonization considered an early proxy for disease that might arise from nonvaccine serotypes, as well as the success of childhood vaccination on indirect effect in the community through the interruption of pneumococcal transmission from vaccinated young children.

Project description:BackgroundTracheostomy tube capping is a commonly used test to determine if the tracheostomy tube can be removed. The success of the capping trial depends on the patient's ability to maintain sufficient spontaneous breathing with an occluded tracheostomy tube. The impact of an occluded tracheotomy tube on airway resistance is currently unknown. The aim of this study was to investigate tracheal pressure during capping or stoma button insertion and potential determinants concerning cuff.MethodsEight cuffed and uncuffed tracheostomy tubes and three stoma buttons of various manufacturers and sizes were inserted into the trachea model. Cuffs were completely deflated or contained atmospheric pressure. The trachea was ventilated bidirectional with a respirator in volume-controlled mode and volume flows 15-60 L/min. Tracheal pressure drop during inspiration as a parameter of pressure required to move gas through the airway was measured.ResultsTracheal pressure drops occurred linearly or irregularly during capping trials to a maximum of 4.2 kPa at flow rates of 60 L/min for atmospheric pressure cuffs. In tracheostomy tubes with completely deflated cuffs, pressure drop in the trachea reaches a maximum of 3.4 kPa at a flow rate of 60 L/min. For tracheostomy tubes with cuff smaller inner or outer diameters do not regularly result in lower tracheal pressure drop. The pressure drop varies between different tracheostomy tubes depending on the manufacturer. In cuffed tracheostomy tubes, we observed three phenomena: sail-like positioning, folding over, and tightening of the cuff during flow. The maximum tracheal pressure drop during stoma button insertion reaches 0.014 kPa.ConclusionsThe cuff is a central element for the pressure drop in the airway and thus airway resistance during spontaneous translaryngeal breathing with a capped TT. Complete deflation reduces the pressure drop in the trachea. Due to deformation of the cuff, measured pressures are irregular as the volume flow is increased. Incomplete deflated cuffs and material characteristics of tracheostomy tubes and cuffs in addition to anatomical and clinical variables may cause unsuccessful capping trials due to increased airway resistance. All stoma buttons showed that pressure drop and thus airway resistance due to stoma buttons has no clinical relevance.

Project description:Regulatory T cells (Treg) diminish immune responses to microbial infection, which may contribute to preventing inflammation-related local tissue damage and autoimmunity but may also contribute to chronicity of infection. Nasopharyngeal carriage of pneumococcus is common in young children and can persist for long periods but it is unknown whether the presence of Treg in the nasopharynx contributes to this persistence. We have investigated the numbers and activities of Foxp3+Treg in adenoidal tissues and their association with pneumococcal carriage in children. Expression of Treg cell-related markers including Foxp3, CD25, CD39, CD127 and CLTA4 were analysed by flow-cytometry in adenoidal mononuclear cells (MNC) and PBMC from children. Unfractionated MNC or Treg-depleted MNC were stimulated with a pneumococcal whole cell antigen (WCA) and T cell proliferation measured. Cytokine production by MNC was measured using a cytometric bead array. Higher numbers of CD25(high)Foxp3(high) Treg expressing higher CD39 and CTLA4 were found in adenoidal MNC than in PBMC. Children with pneumococcus positive nasopharyngeal cultures had higher proportions of Treg and expressed higher levels of CD39 and CTLA-4 than those who were culture negative (-). WCA induced adenoidal Treg proliferation which produce IL10 but not IL17, and CD4 T cell proliferation in Treg-depleted MNC was greater in pneumococcal culture positive than negative children. Significant numbers of Treg with an effector/memory phenotype which possess a potent inhibitory effect, exist in adenoidal tissue. The association of pneumococcal carriage with an increased frequency of adenoidal Treg suggests that Treg in nasal-associated lymphoid tissue (NALT) may contribute to the persistence of pneumococcus in children. Further studies to determine what component and mechanisms are involved in the promotion of Treg in NALT may lead to novel therapeutic or vaccination strategy against upper respiratory infection.

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Pneumococcal colonization among tracheostomy tube dependent children.

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Pneumococcal colonization among tracheostomy tube dependent children.

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