Detection of group A Streptococcus in tonsils from pediatric patients reveals high rate of asymptomatic streptococcal carriage

<p>Abstract</p> <p>Background</p> <p>Group A <it>Streptococcus </it>(GAS) causes acute tonsillopharyngitis in children, and approximately 20% of this population are chronic carriers of GAS. Antibacterial therapy has previously been shown to be insufficient at clearing GAS carriage. Bacterial biofilms are a surface-attached bacterial community that is encased in a matrix of extracellular polymeric substances. Biofilms have been shown to provide a protective niche against the immune response and antibiotic treatments, and are often associated with recurrent or chronic bacterial infections. The objective of this study was to test the hypothesis that GAS is present within tonsil tissue at the time of tonsillectomy.</p> <p>Methods</p> <p>Blinded immunofluorescent and histological methods were employed to evaluate palatine tonsils from children undergoing routine tonsillectomy for adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis.</p> <p>Results</p> <p>Immunofluorescence analysis using anti-GAS antibody was positive in 11/30 (37%) children who had tonsillectomy for adenotonsillar hypertrophy and in 10/30 (33%) children who had tonsillectomy for recurrent GAS pharyngitis. Fluorescent microscopy with anti-GAS and anti-cytokeratin 8 & 18 antibodies revealed GAS was localized to the tonsillar reticulated crypts. Scanning electron microscopy identified 3-dimensional communities of cocci similar in size and morphology to GAS. The characteristics of these communities are similar to GAS biofilms from <it>in vivo </it>animal models.</p> <p>Conclusion</p> <p>Our study revealed the presence of GAS within the tonsillar reticulated crypts of approximately one-third of children who underwent tonsillectomy for either adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis at the Wake Forest School of Medicine.</p> <p>Trial Registration</p> <p>The tissue collected was normally discarded tissue and no patient identifiers were collected. Thus, no subjects were formally enrolled.</p

β-Lactam Effects on Mixed Cultures of Common Respiratory Isolates as an Approach to Treatment Effects on Nasopharyngeal Bacterial Population Dynamics

BACKGROUND: Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae are bacteria present in the nasopharynx as part of normal flora. The ecological equilibrium in the nasopharynx can be disrupted by the presence of antibiotics. METHODOLOGY/PRINCIPAL FINDINGS: A computerized two-compartment pharmacodynamic model was used to explore beta-lactam effects on the evolution over time of a bacterial load containing common pharyngeal isolates by simulating free serum concentrations obtained with amoxicillin (AMX) 875 mg tid, amoxicillin/clavulanic acid (AMC) 875/125 mg tid and cefditoren (CDN) 400 mg bid regimens over 24 h. Strains and MICs (microg/ml) of AMX, AMC and CDN were: S. pyogenes (0.03, 0.03 and 0.015), S. pneumoniae (2, 2 and 0.25), a beta-lactamase positive H. influenzae (BL(+); >16, 2 and 0.06) and a beta-lactamase positive AMC-resistant H. influenzae (BLPACR, >16, 8 and 0.06). Mixture of identical 1:1:1:1 volumes of each bacterial suspension were prepared yielding an inocula of approximately 4 x 10(6) cfu/ml. Antibiotic concentrations were measured both in bacterial and in bacteria-free antibiotic simulations. beta-lactamase production decreased AMX concentrations and fT(>MIC) against S. pneumoniae (from 43.2% to 17.7%) or S. pyogenes (from 99.9% to 24.9%), and eradication was precluded. The presence of clavulanic acid countered this effect of co-pathogenicity, and S. pyogenes (but not BL(+) and S. pneumoniae) was eradicated. Resistance of CDN to TEM beta-lactamase avoided this co-pathogenicity effect, and CDN eradicated S. pyogenes and H. influenzae strains (fT(>MIC) >58%), and reduced in 94% S. pneumoniae counts (fT(>MIC) approximately 25%). CONCLUSIONS/SIGNIFICANCE: Co-pathogenicity seems to be gradual since clavulanic acid countered this effect for strains very susceptible to AMX as S. pyogenes but not for strains with AMX MIC values in the limit of susceptibility as S. pneumoniae. There is a potential therapeutic advantage for beta-lactamase resistant cephalosporins with high activity against streptococci

A regional overview

Abstract is not availabl

Assessment of the impacts of climate change and weather extremes on boreal forests in northern Europe, focusing on Norway spruce

The boreal and boreo-nemoral forests in Europe, which occur in northern and northeastern Europe, are dominated by 2 coniferous species, Norway spruce Picea abies (L.) Karst. being economically the most important one. Forestry is of major economic importance in this region. Forestry planning and climate change scenarios are based on similar (long-term) timescales, i.e. between 70 and 120 yr. Within the EU project 'Modelling the Impact of Climate Extremes' (MICE), we have used 'present day' runs (1961-1990) and future scenarios (2070-2100, emission scenarios A2 and B2 from the Special Report on Emissions Scenarios [SRES]) of the HadRM3 regional climate model to study and model direct and indirect effects of changing climate on Norway spruce in Sweden and northern Europe. According to our results, extreme climate events like spring temperature backlashes and summer drought will increase in frequency and duration. In combination with a raised mean temperature, climate extremes will negatively precondition trees (i.e. increase their susceptibility) to secondary damage through pests and pathogens. Decreased forest vitality also makes stands more susceptible to windthrow. Storm damage is discussed based on a 100 yr storm damage record for Sweden. Marginally increased frequencies and windspeeds of storms may cause disproportionate increases in windthrow. Increased economic hazards can be expected from a combination of the increased volumes of wind-thrown timber, and a greater likelihood of additional generations of spruce bark beetle Ips typographus (further encouraged by the increase in fallen timber), as a result of a changing climate with warmer summers

Climate change and the effect of temperature backlashes causing frost damage in Picea abies

In boreal and nemoboreal forests, tree frost hardiness is modified in reaction to cues from day length and temperature. The dehardening processes in Norway spruce, Picea abies, could be estimated to start when the daily mean temperature is above 5 degreesC for 5 days. Bud burst will occur approximately after 120-170 degree-days above 5 degreesC. dependent on genetic differences among provenances. A reduced cold hardiness level during autumn and spring and an advanced onset of bud burst are expected impacts of projected future global wart-ning. The aim of this study was to test if this will increase the risk for frost damage caused by temperature backlashes. This was tested for Sweden by comparing output from the Hadley Centre regional climate model, HadRM3H, for the period 1961-1990 with future IPCC scenario SRES A2 and B2 for 2070-2099. Different indices for calculating the susceptibility to frost damage were used to assess changes in frost damage risk. The indices were based on: (1) the start of dehardening; (2) the severity of the temperature backlash: (3) the timing of bud burst: and (4) the cold hardiness level. The start of dehardening and bud burst were calculated to occur earlier all over the country. which is in line with the overall warming in both climate change scenarios. The frequency of temperature backlashes that may cause frost damage was calculated to increase in the southern part, an effect that became gradually less pronounced towards the north. The different timing of the onset of dehardening mainly caused this systematic latitudinal pattern. In the south, it occurs early in the year when the seasonal temperature progression is slow and large temperature variations occur. In the north, dehardening will occur closer to the spring equinox when the temperature progression is faster. (C) 2004 Elsevier B.V. All rights reserved

Recorded storm damage in Swedish forests 1901-2000

Severe storm damage has been a recurring problem to the Swedish forestry sector since, at least, the start of the 19th century. This short communication presents a regionally resolved time-series of storm damage in Swedish forests during the last century. Data on storm damage have been gathered from the National Board of Forestry, the Regional Forestry Boards and scientific reports. Storm damage in Swedish forests seems to have increased during the century with a peak around the 1980s. In total 110 million m 3 forest were destroyed by 77 recorded wind storms, with the severe storms in 1954 and 1969 accounting for 49% of the total damage. Reported damage in southern Sweden was normalised against the area of productive forest with trees older than 40 years, for inter annual comparisons. The geostrophic wind was used to describe the regional wind direction during the storm events. Most damage occurred during NNW to SW winds, and by winds from NNE. Apart from a possible shift in storm intensity and frequency, the increase in storm damaged trees can be attributed to changes in regeneration and thinning regimes, variations in storm damage reporting system, increase in forest cover and various damage to root architecture

Comparative histochemical distribution of nerve fibres storing noradrenaline and neuropeptide Y (NPY) in human ovary, fallopian tube, and uterus

Nerves containing noradrenaline were studied by formaldehyde-induced fluorescence and neuropeptide Y (NPY) was visualised by immunohistochemistry in the human ovary, Fallopian tube and uterus. All structures were richly supplied with noradrenergic fibres closely associated with the vascular and non-vascular smooth musculature. NPY-containing nerve terminals were consistently fewer, particularly in the ovary. The best developed nerve supply was found in the tubal isthmus and uterine cervix. Vessels were usually innervated by plexuses of nerves, containing NPY as well as noradrenaline. The discrepancy between the number of the two types of histochemically distinguishable nerves suggests that, if noradrenaline and NPY are co-localised in one and the same nerve, this is not a constant phenomenon in the human female reproductive tract