Detection of plasma anti-lipopolysaccharide (LPS)antibodies against enterohemorrhagic Escherichia coli(EHEC) in asymptomatic kindergarten teachers fromBuenos Aires province

Resumen En Argentina, el síndrome urémico hemolítico causado por Escherichia coli enterohemorrágica (EHEC) tiene la más alta incidencia del mundo. Las infecciones por EHEC tienen un comportamiento endemoepidémico y causan del 20 al 30% de los síndromes de diarrea sanguinolenta en niños menores de 5 años. En el período 2016-2020, se notificaron 272 nuevos casos por año al Sistema de Vigilancia de Salud Nacional. Múltiples factores son responsables de la alta incidencia de SUH en Argentina, incluyendo la transmisión persona-persona. Con el objetivo de detectar posibles portadores asintomáticos de EHEC, realizamos un estudio preliminar de la frecuencia de anticuerpos antilipopolisacáridos contra los serotipos de EHEC más prevalentes en Argentina. El estudio se realizó con muestras de plasma obtenidas de 61 maestras y maestros de jardines de infantes de 26 instituciones del distrito de José C. Paz, localizado en el área suburbana de la provincia de Buenos Aires, Argentina. El 51% de las muestras presentaron anticuerpos contra los serotipos de lipopolisacáridos O157, O145, O121 y O103; el 6,4% de las muestras positivas tuvieron el isotipo IgM (n=2), el 61,3% el isotipo IgG (n=19) y el 32,3% los isotipos IgM e IgG (n=10). Dado que los anticuerpos antilipopolisacáridos presentan usualmente una duración corta, la detección de IgM específica podría indicar una infección reciente. Además, el alto porcentaje de muestras positivas hallado podría indicar una exposición frecuente a las cepas de EHEC en la cohorte estudiada. Asimismo, la gran población de adultos portadores asintomáticos de estas cepas patógenas podría contribuir al comportamiento endémico, a través de la transmisión persona-persona. El perfeccionamiento de programas educacionales continuos en jardines de infantes podría constituir una medida importante para reducir los casos de síndrome urémico hemolítico, no solo en Argentina, sino también en el mundo.

Abstract In Argentina, hemolytic uremic syndrome (HUS) caused by EHEC has the highest incidence in the world. EHEC infection has an endemo-epidemic behavior, causing 20-30% of acute bloody diarrhea syndrome in children under 5 years old. In the period 2016-2020, 272 new cases per year were notified to the National Health Surveillance System. Multiple factors are responsible for HUS incidence in Argentina including person-to-person transmission. In order to detect possible EHEC carriers, we carried out a preliminary study of the frequency of kindergarten teachers with anti-LPS antibodies against the most prevalent EHEC serotypes in Argentina. We analyzed 61 kindergarten teachers from 26 institutions from José C. Paz district, located in the suburban area of Buenos Aires province, Argentina. Fifty-one percent of the plasma samples had antibodies against O157, O145, O121 and O103 LPS: 6.4% of the positive samples had IgM isotype (n=2), 61.3% IgG isotype (n=19) and 32.3% IgM and IgG (n=10). Given that antibodies against LPS antigens are usually short-lived specific IgM detection may indicate a recent infection. In addition, the high percentage of positive samples may indicate a frequent exposure to EHEC strains in the cohort studied, as well as the existence of a large non-symptomatic population of adults carrying pathogenic strains that could contribute to the endemic behavior through person-to-person transmission. The improvement of continuous educational programs in kindergarten institutions could be a mandatory measure to reduce HUS cases not only in Argentina but also globally.

Laboratory and clinical considerations on prosthetic zirconia infrastructures for implants.

Zirconia is a ceramic material that is used for constructing prosthetic infrastructures and implant abutments using CAD/CAM techniques. Although good initial mechanical properties are obtained with zirconia that is partially stabilized by yttrium, it may age in a moist environment, compromising such properties and, consequently, the longevity of the restorative work. To optimize the longevity of this material, it is essential that the clinician and laboratory technician understand its mechanical properties and limitations and take specific precautions needed to maintain its mechanical properties and ensure long-term performance especially in implant prosthetics. This article presents a clinical case where these precautions were taken, emphasizing the key surface treatments advocated for zirconia.

Contagem e prevalência de microrganismos patogênicos e benéficos em indivíduos tabagistas com doença periodontal crônica / Counts and prevalence of pathogenic and benefic microorganisms in smokers with chronic periodontal disease

O objetivo deste estudo foi comparar a contagem e a prevalência dos microrganismos do complexo vermelho (Treponema denticola, Porphyromonas gingivalis e Tannerella forsythia) e do complexo azul (Actinomyces gerencseriae, Actinomyces israelli e Actinomyces naeslundii) na microbiota subgengival em indivíduos tabagistas e não-tabagistas com doença periodontal crônica. Foram selecionados 50 voluntários com periodontite crônica (25 tabagistas – T e 25 não-tabagistas – NT). Os indivíduos foram submetidos a exame clínico periodontal e microbiológico. Os parâmetros clínicos avaliados foram profundidade de sondagem, nível clínico de inserção, placa supragengival visível, sangramento gengival, sangramento à sondagem e supuração. De cada indivíduo foram coletadas entre 6 e 12 amostras de biofilme subgengival, avaliadas para seis espécies bacterianas por meio da técnica Checkerboard DNA-DNA Hybridization. Os resultados clínicos foram semelhantes entre os grupos (T e NT). A exceção foi o percentual de sítios com sangramento gengival, sendo que o grupo T apresentou uma média inferior (9,54 ± 15,31) comparada ao grupo NT (39,44 ± 25,13 – p < 0,001). A única diferença microbiológica foi a contagem de A. gerencseriae diminuída no grupo de tabagistas (p < 0,05). Em conclusão, os perfis clínico-microbiológicos de indivíduos tabagistas e não-tabagistas com periodontite crônica podem ser considerados semelhantes.

The aim of the present study was to compare the levels and the prevalence of bacterial red complex (Treponema denticola, Porphyromonas gingivalis and Tannerella forsythia) and blue complex (Actinomyces gerencseriae, Actinomyces israelli and Actinomyces naeslundii) in the subgingival microbiota of smokers and non-smokers with chronic periodontitis. Fifty subjects wiyh chronic periodontitis were enrolled (25 smokers - S and 25 non smokers - NS). Subjects received clinical and microbiological examination. The clinical parameters evaluated were probing depth, clinical attachment level, visible plaque index, gingival bleeding index, bleeding on probing and suppuration. Six to twelve subgingival biofilm samples were collected per subject, and evaluated for six bacterial species using the Checkerboard DNA-DNA hybridization technique. The clinical results were similar between the groups (S and NS). The exception was the percent of sites with gingival bleeding. The S group showed a lower mean (9.54 ± 15.31) compared with the NS group (39.44 ± 25.13 - p <0.001). The only microbiological difference was the reduced level of A. gerencseriae in smoking group (p < 0,05). In conclusion, the clinical- microbiological profiles of non-smoking and smoking subjects with chronic periodontitis were similar.

[Education for consumers: one of the tools for decreasing the incidence of hemolitic uremic syndrome]. / Educación a los consumidores: una de las herramientas para disminuir la incidencia de casos de síndrome urémico hemolítico.

In order to guarantee that harmless food is ingested by consumers, it is essential that strict hygienic procedures are followed both during the elaboration of food and during the procedures that range from the purchasing, the cooking and the consumption of food. This is an invaluable and unquestionable tool that should be used in order to decrease the incidence of Hemolytic Uremic Syndrome (HUS) in our country. The State, the enterprise owners, and the consumers should take responsibility for this: the State should guarantee the citizens' access to safe food products through an adequate legislation and a mechanism for it to be controlled and obeyed; the enterprise owners should obey the current regulations and provide their employees with education about the importance of these regulations; and the consumers should take responsibility for how they handle food.

Educación a los consumidores: una de las herramientas para disminuir la incidencia de casos de síndrome urémico hemolítico / Education for consumers: one of the tools for decreasing the incidence of hemolitic uremic syndrome

In order to guarantee that harmless food is ingested by consumers, it is essential that strict hygienic procedures are followed both during the elaboration of food and during the procedures that range from the purchasing, the cooking and the consumption of food. This is an invaluable and unquestionable tool that should be used in order to decrease the incidence of Hemolytic Uremic Syndrome (HUS) in our country. The State, the enterprise owners, and the consumers should take responsibility for this: the State should guarantee the citizens access to safe food products through an adequate legislation and a mechanism for it to be controlled and obeyed; the enterprise owners should obey the current regulations and provide their employees with education about the importance of these regulations; and the consumers should take responsibility for how they handle food.(AU)

Educación a los consumidores: una de las herramientas para disminuir la incidencia de casos de síndrome urémico hemolítico / Education for consumers: one of the tools for decreasing the incidence of hemolitic uremic syndrome

In order to guarantee that harmless food is ingested by consumers, it is essential that strict hygienic procedures are followed both during the elaboration of food and during the procedures that range from the purchasing, the cooking and the consumption of food. This is an invaluable and unquestionable tool that should be used in order to decrease the incidence of Hemolytic Uremic Syndrome (HUS) in our country. The State, the enterprise owners, and the consumers should take responsibility for this: the State should guarantee the citizens' access to safe food products through an adequate legislation and a mechanism for it to be controlled and obeyed; the enterprise owners should obey the current regulations and provide their employees with education about the importance of these regulations; and the consumers should take responsibility for how they handle food.