23 research outputs found
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
ÎČ-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
Penetration of penicillin V to tonsillar surface fluid in healthy individuals and in patients with acute tonsillitis
Bacterial invasion of the tonsillar tissues in acute pharyngotonsillitis and in the adenoid: a preliminary study
Achado de bactérias selecionadas em crianças de Trinidad com doença amigdaliana crÎnica Selected bacterial recovery in Trinidadian children with chronic tonsillar disease
Faringoamigdalite na população pediĂĄtrica Ă© largamente tratada com antibiĂłticos. OBJETIVO: Estudar a microflora presente na superfĂcie e no nĂșcleo de amĂgdalas apĂłs adenoamigdalectomia eletiva em crianças. MĂTODO: AmĂgdalas de 102 crianças de Trinidad foram prospectivamente estudadas por meio de culturas e identificaçÔes bacteriolĂłgicas feitas a partir de amostras das superfĂcies e nĂșcleos de suas amĂgdalas entre 2005-2006. RESULTADOS: A partir de 360 amĂgdalas, foram isolados Streptococcus spp. (51,3%), Staphylococcus spp. (42,3%) e Gram-Negativos (6,4%). A identificação de estafilococos e estreptococos tanto na superfĂcie quanto no nĂșcleo foi semelhante (p>0,05). Encontramos mais (p<0,001) Streptococcus spp. nas superfĂcies (82,2%) do que nos nĂșcleos (63,3%); a prevalĂȘncia de estreptococos alfa-hemolĂticos foi maior (p<0,001) do que aquela de estreptococos beta-hemolĂticos nas superfĂcies (74,4% vs. 18,6%) do que nos nĂșcleos (58,9% vs. 13,7%). NĂŁo houve concordĂąncia entre superfĂcies e nĂșcleos com relação a estreptococos (p<0,0004) e estreptococos alfa-hemolĂticos (p<0,007). Estreptococos beta-hemolĂticos foram mais identificados (p<0,05) em crianças dentre 6-16 anos do que naquelas entre 1-5 anos de idade (31% e 23,8% vs 12,5% e 8%). A prevalĂȘncia de S. pyogenes na superfĂcie e no nĂșcleo foi de (84,6% vs 70%) e (50,0% vs 25,0%) em crianças de maior faixa etĂĄria e crianças mais novas, respectivamente. Klebsiella spp. (6,6%, 2,2%), Proteus (4,4%, 4,4%) e Pseudomonas (4,4 %, 1,1%) cresceram nas superfĂcies e nĂșcleos, respectivamente. CONCLUSĂO: As superfĂcies amigdalianas tinham mais estreptococos e estreptococos hemolĂticos do que seus nĂșcleos. Crianças mais velhas tiveram mais estreptococos beta-hemolĂticos, e sĂŁo altamente colonizadoras de S. pyogenes. Sugerimos estudos que investiguem os mecanismos de aderĂȘncia estreptocĂłcica em crianças de Trinidad.<br>Pharyngotonsillitis in children is widely treated with antibiotics. AIM: To examine tonsil surface and core microflora following elective adenotonsillectomy in children. METHODS: Tonsils of 102 Trinidadian children were prospectively examined for surface and core bacteriological culture and identification between 2005-2006. RESULTS: Tonsils (360) yielded 800 isolates of Streptococcus spp. (51.3%), Staphylococcus spp. (42.3%) and Gram-negative genera (6.4%). Surface and core recovery of staphylococci and streptococci were similar (p>0.05). More (p<0.001) surfaces (82.2%) than cores (63.3%) grew Streptococcus spp.; α-haemolytic Streptococcus prevalence was higher (p<0.001) than Ă-haemolytic Streptococcus on surfaces (74.4% vs. 18.6%) than cores (58.9% vs. 13.7%). Surfaces and cores were not concordant for streptococci (p<0.0004) and α-haemolytic Streptococcus (p<0.007). Surface and core Ă-haemolytic Streptococcus yield was higher (p<0.05) in 6-16 than 1-5 year olds (31% and 23.8% vs 12.5% and 8%). S. pyogenes surface and core prevalence was (84.6% vs 70%) and (50.0% vs 25.0%) in older and younger children respectively. Klebsiella spp. (6.6 %, 2.2%), Proteus (4.4%, 4.4%) and Pseudomonas (4.4 %, 1.1%) grew on surfaces and cores respectively. CONCLUSION: Tonsil surfaces yield higher surface than core carriage for streptococci overall and for α haemolytic streptococci. Older children grow more β-haemolytic streptococci and are high colonizers of S. pyogenes. Studies probing the mechanisms of streptococcal adhesions in Trinidadian children are suggested