Respuesta inmunitaria al SARS-CoV-2 y factores asociados previo a la vacunación, en personal de salud de atención primaria en una comuna de Santiago, Chile

Resumen Introducción: La pandemia de COVID-19 surgida en China a fines de 2019, se extendió rápidamente por el mundo, con casi 600 millones de casos y 6,3 millones de fallecidos en la actualidad. Los más afectados fueron los trabajadores de la salud con al menos tres veces más riesgo que la comunidad general de contraer la enfermedad. La mayoría de los estudios sobre seroprevalencia en trabajadores de la salud, se enfocan en establecimientos de atención hospitalaria y no se ha indagado con igual intensidad sobre lo que ocurre en la Atención Primaria de Salud (APS). Objetivos: Determinar prevalencia de SARS-CoV-2 mediante anticuerpos IgG en personal de atención primaria de comuna de La Pintana y explorar sus características clínicas y factores de riesgo, previo a la vacunación en Chile. Metodología: Diseño transversal realizado en noviembre 2020. Se recogieron datos sociodemográficos y clínicos mediante entrevista cara a cara, previa firma de consentimiento. Se determinó IgG específica mediante ELISA que utiliza proteína N y S. Las diferencias entre sujetos positivos y negativos se estudiaron mediante análisis bivariado y para asociaciones encontradas, se desarrollaron modelos multivariados controlando potenciales variables de confusión. El estudio contó con la aprobación del Comité Ético Científico de la Universidad del Desarrollo. Resultados: Participaron 463 funcionarios (51,4%) encontrando prevalencia de 21,8%. Los factores de riesgo fueron edad menor, ser médico y haber sido contacto estrecho de un caso. El 22% fue asintomático. Entre quienes presentan anosmia o ageusia, la probabilidad de IgG+ fue superior a 70%. Los títulos de anticuerpos aumentan significativamente con la gravedad. Conclusiones: La prevalencia en personal de atención primaria encontrada es concordante con la evidencia previa en trabajadores de salud. La menor edad y la profesión de médico se asocian a un mayor riesgo de enfermar.

Abstract Background: The COVID-19 pandemic that emerged in Wuhan, China at the end of 2019, spread rapidly around the world with almost 600 million cases and 6.3 million deaths today. The most affected were health workers with at least three times the risk of contracting the disease than the general community. Most studies on seroprevalence in health workers focus on hospital care establishments and what happens in Primary Health Care (PHC) has not been investigated with the same intensity. Aim: To determine the prevalence of SARS-CoV-2 using IgG antibodies in primary health care personnel in La Pintana commune, risk factors and clinical characteristics, prior to vaccination in Chile. Methods: A cross-sectional design carried out in November 2020. Sociodemographic and clinical data were collected through face-to-face interviews, after providing informed consent. Specific IgG was determined by ELISA using N and S proteins. The differences between positive and negative subjects were studied using bivariate analysis and multivariate models, controlling for potential confounding variables. The study was approved by the Universidad del Desarrollo Scientific Ethics Committee. Results: 463 employees (51.4%) participated, finding a prevalence of 21.8%. The risk factors found were younger age, being a physician and having been in close contact with a case. 22% were asymptomatic. Among those with anosmia/ageusia, the probability of IgG+ was greater than 70%. Antibody titers increase with severity. Conclusions: Prevalence found in primary health care personnel is consistent with previous evidence. Younger age and medical profession are associated with a higher risk of illness.

Cirugía pulmonar en tuberculosis / Surgery for pulmonary tuberculosis: Review of 33 operated patients

Background: Surgical treatment for pulmonary tuberculosis is mainly ¡imited to the management of sequelae such as bronchiectasis, hemoptysis and brochopleural fistulae. Aim: To review the data of patients who underwent surgical treatment for pulmonary tuberculosis. Material and methods: Retrospective review of 33 patients aged 18 to 73 years (24 males) who underwent lung resection surgery for the management of pulmonary tuberculosis. Follow-up data were obtained from outpatient visit records and registries of the national tuberculosis program. Results: The reasons to perform surgery were the following: fifteen for hemoptysis, nine for lung destruction and nine for an active and multiresistant disease. No patient died in the postoperative period. The morbidity observed included empyema (n =5), pneumothorax (n =2), bronchopleural fístula (n =2) and hemothorax (n =2). At six months offollow up, six of the nine patients with active tuberculosis had negative acid-fast bacilli on sputum smear. Two of these patients died, one due to respiratory failure and another by an unrelated cause. Both dead patients had negative acid-fast bacilli on sputum smear. Conclusions: Surgery in pulmonary tuberculosis has a high rate of complications butmay be usefulin selected patients.

Staphylococcus aureus comunitario resistente a cloxacilina: comunicación de los primeros cinco casos descritos en Chile / Community acquired infections with methicillin resistant strains of Staphylococcus aureus: report of five cases

Community acquired infections with methicillin resistant strains of Staphylococcus aureus (MRSA) infections have a more aggresive clinical course and involve mostly skin and lungs. These infections appear as outbreaks among prisoners, sportsmen, men having sex with men and military personnel. The higher aggressiveness of these strains is due to the production of several toxins, mainly Panton- Valentine leukocidine. The detection of the gene that codes for this toxin is a distinctive feature of these strains. We report five patients with community acquired MRSA infections. The clinical presentation was a skin infection in all. One patient had a pleuropneumonia in addition. Apart for resistance to beta-lactam antimicrobials, the strains were resistant to erythromycin and ciprofloxacin. Patients were treated with vancomycin, clotrimoxazole or intravenous clindamycin with a good evolution. An epidemiológical surveillance for community acquired MRSA strain infections should be started and measures to adequately treat infected patients and avoid dissemination should be implemented.