Epidemiología de la faringitis estreptocócica. Período enero de 2018 - diciembre de 2021 / Epidemiology of streptococcal pharyngitis. January 2018 - December 21

La faringoamigdalitis es uno de los motivos más frecuentes de consulta en pediatría. Aproximadamente un 70-80% de las faringoamigdalitis son de etiología viral. El 20-30% restante son de origen bacteriano. El agente causal más frecuente es Streptococcus pyogenes (estreptococo ß-hemolítico del grupo A). El rol de Streptococcus dysgalactiae subsp. equisimilis, (estreptococos ß-hemolíticos grupos C y G) fue claramente establecido como agente etiológico en la faringitis bacteriana, tanto en niños como en adultos. Se realizó un análisis descriptivo y retrospectivo entre enero 2018 y diciembre de 2021. Se evaluó la prevalencia de faringitis estreptocócica, la edad, el período estacional, los agentes etiológicos y la resistencia a macrólidos durante los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021). Se analizaron 11 396 muestras de exudados de fauces de pacientes con sospecha de faringitis bacteriana; las mismas se procesaron mediante el uso de técnicas microbiológicas convencionales. En el período estudiado el porcentaje de positividad de los cultivos de exudados de fauces se mantuvo constante. Al comparar los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021) se observó una disminución en el número de aislados de S. pyogenes con un aumento de S. dysgalactiae subsp. equisimilis, mientras que la resistencia a macrólidos encontrada fue superior en S. pyogenes y para S. dysgalactiae subsp. equisimilis se mantuvo constante. Es importante realizar el cultivo para la identificación del agente etiológico y determinar la sensibilidad antibióticapara continuar con la vigilancia epidemiológica de la resistencia a los macrólidos, porque representan una opción en pacientes alérgicos a ß-lactámicos (AU)

Pharyngotonsillitis is one of the most frequent reasons for consultation in children. Approximately 70-80% of pharyngotonsillitis are of viral etiology. The remaining 20-30% are bacterial in origin. The most frequent causative agent is Streptococcus pyogenes (group A ß-hemolytic streptococcus). Streptococcus dysgalactiae subsp. equisimilis (ß-hemolytic streptococcus groups C and G) was clearly established as an etiologic agent in bacterial pharyngitis in both children and adults. A descriptive and retrospective analysis was conducted between January 2018 and December 2021. The prevalence of streptococcal pharyngitis, age, seasonal period, etiologic agents, and macrolide resistance during the pre-COVID-19 (2018-2019) and COVID-19 (2020-2021) periods were evaluated. We analyzed 11 396 specimens of swabs from patients with suspected bacterial pharyngitis. Conventional microbiological techniques were used. In the study period, the percentage of positivity of swab cultures remained constant. When comparing the preCOVID-19 (2018-2019) and COVID-19 (2020-2021) periods, a decrease in the number of S. pyogenes isolates was observed with an increase in S. dysgalactiae subsp. equisimilis, while the resistance to macrolides found was higher for S. pyogenes and remained constant for S. dysgalactiae subsp. equisimilis. The identification of the etiologic agent and determination of antibiotic sensitivity are important for epidemiological surveillance of macrolide resistance, as they are a treatment option in patients who are allergic to ß-lactams (AU)

Proteolytic activity in salivary gland products of sheep bot fly (Oestrus ovis) larvae.

This study identified and characterized hydrolytic enzymes in salivary gland products of Oestrus ovis larvae. Third instars were collected from the heads of slaughtered goats. Salivary glands were extracted, their products obtained by centrifugation and the enzymatic profile determined. Optimum pH, temperature of maximum proteolytic activity, thermal stability, and resistance of salivary gland products were determined on collagen and subclasses of proteases were identified using protease inhibitors. Zymograms were used to determine the molecular weight of proteases. Antigenic protein bands were revealed by immunoblotting using sera obtained from experimentally infested goats. Seven positive enzymatic activities were detected in salivary gland products: acid phosphatase, naphthol-AS-BI-phosphohydrolase, esterase (C4), esterase lipase (C8), leucine arylamidase, alpha-glucosidase and N-acetyl-beta-glucosaminidase. Optimum pH for proteolytic activity was 8.0; proteolytic activity increased with temperature (10-50 degrees C) then drastically decreased at 60 degrees C. Proteases in O. ovis salivary gland products belong to the serine subclass. In Zymograms, bands of proteolytic activity were detected in the 20-63 kDa range; the immunoblot showed three antigenic bands, one of them related to a protease band (63 kDa). Serine proteases in O. ovis salivary gland products are most likely involved in larval nutrition and host immuno-modulation.

Mucosal immune response of spotted sand bass Paralabrax maculatofasciatus (Steindachner, 1868) orally immunised with an extracellular lectin of Aeromonas veronii.

To assess the immunogenic and immunoprotective role of the extracellular lectin from Aeromonas veronii (MCBP), which has affinity for mucosal constituents such as mucin, lactoferrin, immunoglobulins and collagen, spotted sand bass (Paralabrax maculatofasciatus) were orally immunised either with soluble MCBP, adjuvant-conjugated MCBP or immobilised MCBP on latex microspheres. The results suggest that the MCBP is capable of eliciting protective immunity against A. veronii infections when administered orally. The highest mucosal immune response was elicited in fish immunised with MCBP covalently linked to cholera toxin B subunit (CTB) or to Escherichia coli heat-labile toxin (hLT). MCBP-CTB was found to elicit immunoprotection against a challenge with live Aeromonas cells with a relative percent survival of almost 70% and without the expression of the severe histopathological alterations induced by A. veronii.

Streptococcal erythrogenic toxin B induces apoptosis and proliferation in human leukocytes.

BACKGROUND: Previous reports have shown the presence of erythrogenic toxin type B (ETB), apoptosis, proliferation, and leukocyte infiltration in biopsies from patients with acute poststreptococcal glomerulonephritis (APSGN). METHODS: Attempting to correlate the apoptotic and proliferative events with the interaction of ETB or its precursor (ETBP) with leukocytes, mononuclear leukocytes from 12 healthy subjects were cultured with ETB or ETBP to analyze the levels of apoptosis, proliferation, expression of modulatory apoptosis gene products, and oxidative metabolism. After four days of incubation, cells were assessed for apoptosis by morphological criteria, annexin V assay, and terminal deoxy transferase uridine triphosphate nick end-labeling (TUNEL) assay. The expression of regulatory apoptosis genes was assessed by relevant monoclonal antibodies; proliferation was by incorporation of radioactive thymidine; and oxidative metabolism was by oxidation of 2',7'-dichlorofuorescein diacetate to 2',7'-dichlorofuorescein. Neutralization of Fas-L and cysteine protease activity of ETB were performed by incubation of ETB-treated leukocyte cultures with anti-human Fas-L mAb or with E64, respectively. RESULTS: Elevated levels of apoptosis in ETBP/ETB-treated leukocytes were found when compared with controls: morphological criteria (P < 0.01), Annexin V (control, 5.01 +/- 0.61; ETBP, 10.60 +/- 1.98%, P = 0.0005), and TUNEL (control, 12.5 +/- 2.6; ETBP, 20.56 +/- 3.06%, P = 0.001; ETB, 30.69 +/- 5.05%, P = 0.001). Increased expression of apoptosis was accompanied by increased expression of Fas (control, 20.15 +/- 5.28; ETBP, 43.51 +/- 5.6%, P = 0.03; ETB, 47.16 +/- 5.54%, P = 0.01), Fas ligand (control, 5.64 +/- 2.38; ETBP, 11.66 +/- 3.65%, P = 0.04; ETB, 16.39 +/- 5.05%, P = 0.02) and p53 products (control, 9.22 +/- 3.44; ETBP, 22.82 +/- 5.72%, P = 0.01; ETB, 24.60 +/- 5.20%, P = 0.01). Treatment of ETB-leukocyte cultures with anti-human Fas-L exhibited 2.2-fold lower apoptosis expression. Treatment with E64 significantly abrogated the apoptotic effect of ETB. There was no increment on leukocyte oxidative metabolism. Mononuclear leukocytes also showed elevated levels of proliferation when treated with different concentrations (from 50 to 6.2 microg/mL) of streptococcal proteins (Stimulation index ranging: ETBP, 5.6 +/- 1.9 to 6.4 +/- 1.9; ETB, 9.9 +/- 2.8 to 13.9 +/- 3.8). CONCLUSIONS: These results delineate an additional pathway for the pathogenesis of APSGN related to the role of cationic streptococcal ETB or ETBP on the induction of apoptosis and proliferation during the course of the disease.

Analysis of the interaction of Aeromonas caviae, A. hydrophila and A. sobria with mucins.

Aeromonas species are known to be involved in human gastrointestinal diseases. These organisms colonize the gastrointestinal tract. Aeromonas hydrophila, A. caviae, and A. sobria have been demonstrated microscopically to adhere to animal cell lines that express mucous receptors, but quantitative studies of adherence to mucosal components such as mucin have not been published to date. Purified bovine submaxillary gland, hog gastric mucin, and fish skin mucin were used as a model to study mucin-binding activity among A. caviae, A. hydrophila, and A. sobria strains. Our findings revealed that binding of radiolabeled and enzyme-conjugated mucins to Aeromonas cells varied depending on the labeling procedure. The highest binding was observed when the three mucin preparations were labeled with horseradish peroxidase. Binding of the various horseradish peroxidase-labeled mucins by A. caviae, A. hydrophila, and A. sobria cells is a common property among Aeromonas species isolated from human infections, diseased fish, and from environmental sources. The proportion of Aeromonas strains which bind the various horseradish peroxidase-labeled mucins was significantly higher for A. hydrophila than for A. caviae and A. sobria. Bacterial cell-surface extracts containing active mucin-binding components recognized the horseradish peroxidase-labeled mucins. The molecular masses of the mucin-binding proteins were estimated by SDS-PAGE and Western blot as follows: A. caviae strain A4812 (95 and 44 kDa); A. hydrophila strain 48748 (97, 45, 33 and 22 kDa); and A. sobria strain 48739 (95 and 43 kDa). Mucin interaction with Aeromonas cells was also studied in terms of growth in mucin-rich media. The culture conditions greatly influence the expression of A. hydrophila mucin-binding activity.