Initial events in the pathogenesis of acute tonsillitis caused by Streptococcus pyogenes

Pen-Based Swine Oral Fluid Samples Contain Both Environmental and Pig-Derived Targets

Laboratory methods for detecting specific pathogens in oral fluids are widely reported, but there is little research on the oral fluid sampling process itself. In this study, a fluorescent tracer (diluted red food coloring) was used to test the transfer of a target directly from pigs or indirectly from the environment to pen-based oral fluid samples. Pens of ~30, ~60, and ~125 14-week-old pigs (32 pens/size) on commercial swine farms received one of two treatments: (1) pig exposure, i.e., ~3.5 mL of tracer solution sprayed into the mouth of 10% of the pigs in the pen; (2) environmental exposure, i.e., 20 mL of tracer solution was poured on the floor in the center of the pen. Oral fluids collected one day prior to treatment (baseline fluorescence control) and immediately after treatment were tested for fluorescence. Data were evaluated by receiver operating characteristic (ROC) analysis, with Youden's J statistic used to set a threshold. Pretreatment oral fluid samples with fluorescence responses above the ROC threshold were removed from further analysis (7 of 96 samples). Based on the ROC analyses, oral fluid samples from 78 of 89 pens (87.6%), contained red food coloring, including 43 of 47 (91.5%) pens receiving pig exposure and 35 of 42 (83.3%) pens receiving environmental exposure. Thus, oral fluid samples contain both pig-derived and environmental targets. This methodology provides a safe and quantifiable method to evaluate oral fluid sampling vis-à-vis pen behavior, pen size, sampling protocol, and target distribution in the pen.

Application of an enzyme-labeled antigen method for visualizing plasma cells producing antibodies against Strep A, a carbohydrate antigen of Streptococcus pyogenes, in recurrent tonsillitis

Streptococcus pyogenes is the main causative pathogen of recurrent tonsillitis. Histologically, lesions of recurrent tonsillitis contain numerous plasma cells. Strep A is an antigenic carbohydrate molecule on the cell wall of S. pyogenes. As expected, plasma cells in subjects with recurrent tonsillitis secrete antibodies against Strep A. The enzyme‐labeled antigen method is a novel histochemical technique that visualizes specific antibody‐producing cells in tissue sections by employing a biotin‐labeled antigen as a probe. The purpose of the present study was to visualize plasma cells producing antibodies reactive with Strep A in recurrent tonsillitis. Firstly, the lymph nodes of rats immunized with boiled S. pyogenes were paraformaldehyde‐fixed and specific plasma cells localized in frozen sections with biotinylated Strep A. Secondly, an enzyme‐labeled antigen method was used on human tonsil surgically removed from 12 patients with recurrent tonsillitis. S. pyogenes genomes were PCR‐detected in all 12 specimens. The emm genotypes belonged to emm12 in nine specimens and emm1 in three. Plasma cells producing anti‐Strep A antibodies were demonstrated in prefixed frozen sections of rat lymph nodes, 8/12 human specimens from patients with recurrent tonsillitis but not in two control tonsils. In human tonsils, Strep A‐reactive plasma cells were observed within the reticular squamous mucosa and just below the mucosa, and the specific antibodies belonged to either IgA or IgG classes. Our technique is effective in visualizing immunocytes producing specific antibodies against the bacterial carbohydrate antigen, and is thus a novel histochemical tool for analyzing immune reactions in infectious disorders.

Induction of NF-kappaB nuclear translocation in human respiratory epithelial cells by group A streptococci

The activation of the transcription factor NF-kappaB and the production of inflammatory mediators play an essential role in the host response to pathogenic organisms. The objective of this study was to investigate the ability of group A streptococci (GAS) to stimulate the nuclear translocation of NF-kappaB in cultured human epithelial (HEp-2) cells. Infection of HEp-2 cells with a strain of Streptococcus pyogenes capable to efficiently internalize HEp-2 cells (strain A40) resulted in translocation of NF-kappaB during the first 15 min of infection, reaching a peak after 30 min that persisted at slightly lower levels 1h thereafter. Inhibition of bacterial internalization by cytochalasin D resulted in lower levels of nuclear NF-kappaB at 30 min and 1h of infection, however, it did not affect the initial nuclear translocation of NF-kappaB observed at 15 min postinfection. These results suggest that adhesion of S. pyogenes alone might be sufficient to stimulate nuclear translocation of NF-kappaB, however, bacterial internalization is required for a sustained nuclear translocation of this transcriptional factor.

Clinical evaluation methods for new antimicrobial agents to treat respiratory infections: Report of the Committee for the Respiratory System, Japan Society of Chemotherapy

The present report constitutes an attempt to improve and modify the existing clinical evaluation method for new antimicrobial agents to treat respiratory infections. One year ago, a general guideline on the clinical evaluation of antimicrobial agents to treat respiratory infections was drafted in Japanese, leaving scope for critical discussion, and this has been translated into English, as there were no major changes. In this report, respiratory infections have been discussed under the headings "acute respiratory tract infection" and pneumonia and acute exacerbation of chronic pulmonary diseases. Standardized criteria were set for the assessment of severity of infection and effectiveness of the antimicrobial agent in question. Severity was evaluated on the basis of a combined assessment of the severity of infection and severity of the clinical condition of the patients. Clinical effectiveness of the antimicrobial agent used was evaluated on the basis of clinical outcome as well as microbiological outcome of the trial. Body temperature, local pain, cough, change in sputum quality, peripheral white blood cell count, C-reactive protein level, and chest radiograph were used as the parameters for the evaluation. To maintain the quality of specimens to be examined, Geckler's classification of specimens was used. This report was constructed based on the analysis of large amounts of material collected over the years, incorporating internal and external factors concerning the present evaluation methods. The newly suggested standardized criteria for clinical evaluation of the new antimicrobial drugs are expected to be practiced properly hereupon and subjected to further improvement if necessary.