Patrón de neumonía organizativa en TC de tórax: prevalencia y asociación con resultados clínicos en una cohorte de pacientes con COVID-19 grave/crítico / Organizing Pneumonia Pattern on Chest CT: Prevalence and Association with Clinical Outcomes in a Cohort of Patients with Severe/Critical COVID-19

Introducción: La neumonía por COVID-19 puede presentarse con dos patrones radio-lógicos: daño alveolar difuso o neumonía organizativa. Estos patrones tienen diferente evolución y pronóstico en pacientes sin infección por COVID-19. Nuestro objetivo fue evaluar la prevalencia del patrón radiológico de neumonía organizativa y su asociación con los desenlaces clínicos.Métodos: Se realizó un estudio de cohorte retrospectivo que incluyó a pacientes adultos hospitalizados por COVID-19 grave/crítica a los que se les realizó una tomografía computarizada de tórax en los 21 días posteriores al diagnóstico. Los patrones radiológicos fueron revisados y clasificados por dos radiólogos expertos. Resultados: De los 80 pacientes incluidos, el 89% (n=71) presentaron un patrón compatible con neumonía organizativa. Los principales hallazgos radiológicos fueron la distribución multilobar (98,7%) y bilateral (97,6%) con opacidades en vidrio esmerilado (97,6%). El 44% (n=33) de los sujetos requirió ingreso en cuidados intensivos, de los cuales el 24% (n=19) recibió ventilación mecánica. La presencia de neumonía organizativa se asoció de forma independiente con una disminución de las probabilidades de ventilación mecánica o muerte (Odds ratio 0,14; intervalo de confianza del 95%: 0,02 - 0,96; valor de p 0,045) en un modelo multivariado que incluía la edad, el sexo, el IMC y la afectación pulmonar en la TC.Conclusiones: Un patrón radiológico de neumonía organizativa es altamente prevalen-te en pacientes con COVID-19 grave/crítico y se asocia con mejores resultados clínico

Introduction: COVID-19 pneumonia can present with two distinct radiologic patterns: diffuse alveolar damage or organizing pneumonia. These patterns have been linked to different outcomes in non-COVID-19 settings. We sought to assess the prevalence of organizing pneumonia radiologic pattern and its association with clinical outcomes. Methods: We performed a retrospective cohort study including adult patients hospita- lized for severe/critical COVID-19 who underwent chest computed tomography within 21 days of diagnosis. Radiologic patterns were reviewed and classified by two expert radiologists. Results: Among 80 patients included, 89% (n=71) presented a pattern consistent with organizing pneumonia. The main radiologic findings were multilobar (98.7%) and bilateral (97.6%) distribution with ground glass opacities (97.6%). Intensive care admission was required for 44% (n=33) of subjects, of which 24% (n=19) received mechanical ventilation. The presence of organizing pneumonia was independently associated with a decreased odds of mechanical ventilation or death (Odds ratio 0.14; 95% confidence interval 0.02 - 0.96; p value 0.045) in a multivariate model including age, gender, BMI and lung involvement on CT. Conclusion: A radiologic pattern of organizing pneumonia is highly prevalent in patients with severe/critical COVID-19 and is associated with improved clinical outcomes.

Factores pronósticos de mortalidad a 30 días en neumonía por SARS-CoV-2 / Prognostic Factors for 30-day Mortality in SARS-CoV-2 Pneumonia

Introducción: SARS-CoV-2 ha causado millones de muertes a nivel global desde su primer caso reportado en China. En Guatemala existen pocos estudios que describan los factores pronósticos. Nuestro objetivo fue determinar los factores asociados de mortalidad a 30 días en pacientes con neumonía (Nm) por SARS-CoV-2 y construir un modelo predictor. Material y Métodos: Estudio retrospectivo en 144 sujetos en el Hospital Roosevelt de marzo a diciembre 2020 con criterios de Nm por SARS-CoV-2. Se revisó el expediente médico para datos clínicos y de laboratorio desde ingreso hasta alta hospitalaria o muerte. Resultados: Se evaluaron 105 hombres y 39 mujeres con media de edad 53 años. El 47% tenía comorbilidades como diabetes mellitus 2 e hipertensión arterial sistémica. Promedio de días de hospitalización: 13. Cuadros leves a moderados de Síndrome de Distrés Respiratorio Agudo (SDRA): 92%. Se indicó ventilación mecánica invasiva (VMI) a 46 pacientes. La mortalidad general fue 35%. Factores asociados a mortalidad a 30 días: edad ≥50 años, inicio de síntomas ≥7 días, SDRA severo, radio NL >4,4, recibir VMI, alteración en LDH y procalcitonina. Nuestro modelo mostró que los mejores predictores de mortalidad eran alteración en procalcitonina (OR: 4,45), recibir VMI (OR: 112) y días de estancia hospitalaria (OR: 1,12) con precisión de 91,5% y área bajo la curva de 94,4%. Conclusiones: Los factores pronósticos de mortalidad en pacientes guatemaltecos con Nm por SARS-CoV-2 son múltiples e incluyen rasgos demográficos, clínicos y serológicos; identificarlos y contar con un modelo pronóstico ayudará a brindar atención médica de precisión.

Introduction: SARS-CoV-2 has caused millions of deaths globally since its first case was reported in China. In Guatemala, few studies describe prognostic factors. Our objective was to determine the factors associated with 30 day mortality in patients with Pneumonia (Nm) due to SARS-CoV-2 and to build a predictor model. Material and Methods: Retrospective study in 144 subjects at Roosevelt Hospital from March to December 2020 with Nm criteria for SARS-CoV-2. The medical record was rviewed, obtaining clinical and laboratory data from admission to hospital discharge or death. Results: 105 men and 39 women with an average age of 53 years were evaluated. 47% had comorbidities, with type 2 diabetes mellitus and systemic arterial hypertension being common. The average number of days of hospitalization was 13. 92% had mild to moderate acute respiratory distress syndrome (ARDS). Invasive mechanical ventila-tion (IMV) was indicated for 46 patients. Overall mortality was 35%. The factors asso-ciated with 30-day mortality were age ≥50 years, the onset of symptoms ≥7 days, severe ARDS, N/L ratio >4.4, receiving IMV, alterations in LDH, and procalcitonin. Our model showed that the best predictors of mortality were altered procalcitonin (OR: 4.45), receiving IMV (OR: 112), and days of hospital stay (OR: 1.12) with precision of 91.5% and area under the curve of 94.4%. Conclusions: The prognostic factors of mortality in Guatemalan patients with Nm due to SARS-CoV-2 are multiple and include demographic, clinical and serological features; identifying them and having a prognostic model will help provide precision medical care.

Infección por Helicobacter pylori y factores asociados en adultos de la sierra norte del Perú / Helicobacter pylori infection and associated factors in adults from the northern highlands of Peru

INTRODUCCIÓN: Helicobacter pylori afecta a más de 50% de la población mundial, siendo más prevalente en poblaciones de nivel socioeconómico bajo; esta bacteria constituye la principal causa de cáncer gástrico a nivel global. OBJETIVO: Determinar la frecuencia y los factores asociados a la infección por H. pylori en personas adultas que viven en el centro histórico de la ciudad de Cajamarca, en el norte del Perú. MATERIAL Y MÉTODO: Estudio descriptivo que incluyó 124 personas encuestadas mediante un cuestionario y evaluadas mediante endoscopía y cultivo de biopsia gástrica. Una biopsia por persona fue sometida a prueba de ureasa y los cultivos se confirmaron por reacción de polimerasa en cadena (RPC). RESULTADOS: La frecuencia de infección fue de 60,5 % (IC 95% 51,3 - 69,2). El análisis univariado demostró asociación significativa entre la infección y la edad (p = 0,002), y entre la infección y el antecedente de patología gástrica (p = 0,015). El análisis multivariado reveló dos factores asociados: edad (OR = 0,94; IC95% 0,90-0,97) y antecedente de infección por H. pylori (OR = 0,23; IC95% 0,08 - 0,67). CONCLUSIONES: Existe alta frecuencia de infección por H. pylori en esta población; la edad y el antecedente de infección constituyen factores asociados que deben evaluarse con mayor profundidad.

BACKGROUND: Helicobacter pylori affects more than 50% of the world's population, being more prevalent in populations of low socioeconomic status. H. pylori is the main cause of gastric cancer globally. AIM: To establish the frequency and factors associated with H. pylori infection in adults living in the historic center of Cajamarca City, in northern Peru. METHODS: This was a descriptive study that included 124 individuals surveyed through a questionnaire and evaluated through endoscopy and gastric biopsy culture. One biopsy per person underwent the urease test, and the cultures were confirmed by PCR. RESULTS: The frequency of infection was 60.5% (95% CI 51.3 - 69.2). In the univariate analysis, there was a significant association between the infection and age (p = 0.002), and between the infection and a history of gastric pathology (p = 0.015). The multivariate analysis revealed two associated factors: age (OR = 0.94; 95% CI 0.90 - 0.97), and history of H. pylori infection (OR = 0.23; 95% CI 0.08 - 0.67). CONCLUSIONS: There is a high frequency of H. pylori infection in this population, and the age and history of H. pylori infection are factors that should be further evaluated.

Perfil molecular de cáncer de endometrio en mujeres de Bogotá DC, Colombia / Molecular profile of endometrial cancer in women from Bogota DC, Colombia

Introducción: El cáncer de endometrio ocupa el sexto lugar en incidencia del cáncer en mujeres. La caracterización molecular de este cáncer permite optimizar la estratificación de riesgo para mejorar el tratamiento de las pacientes. Objetivo: Determinar el perfil molecular TCGA de pacientes con cáncer de endometrio en Bogotá, D.C., Colombia. Método: Estudio descriptivo en una cohorte de pacientes con cáncer de endometrio. Las mutaciones en los exones 9 a 14 del gen POLE fueron identificadas mediante amplificación por reacción en cadena de la polimerasa, seguida de secuenciación Sanger y análisis bioinformático. La expresión de las proteínas MMR y p53 se identificó mediante inmunohistoquímica. Resultados: Se incluyeron 40 pacientes con una mediana de edad de 66 años. El 15% presentaron mutaciones en el dominio exonucleasa de POLE. El 32% de las pacientes que no presentaron mutaciones manifestaron deficiencia en el sistema MMR. El 43,47% de las pacientes sin mutaciones en POLE ni alteración del sistema MMR presentaron alteración de la proteína p53. Conclusiones: La población de cáncer de endometrio analizada presenta un perfil molecular TCGA similar a lo reportado para otras poblaciones.

Introduction: Endometrial cancer ranks sixth in cancer incidence among women. Its molecular characterization allows for a more precise risk stratification with the aim of improving patient treatment. Objective: To determine the TCGA molecular profile of patients with endometrial cancer in Bogota, Colombia. Method: A descriptive study of a cohort of patients with endometrial cancer. The expression of MMR proteins and p53 was identified through immunohistochemistry. Mutations in exons 9 to 14 of the POLE gene were identified through polymerase chain reaction amplification, followed by Sanger sequencing and bioinformatic analysis. Results: Forty patients were included in the study, with a median age of 66 years, 15% of them exhibited mutations in the exonuclease domain of POLE, while 32% of patients without mutations showed deficiency in the MMR system. Forty three percent of patients without mutations in POLE or MMR alterations showed aberrant p53 protein expression. Conclusions: The analyzed population of endometrial cancer presents a TCGA molecular profile similar to that reported for other populations.

Detección e integración del virus del papiloma humano de alto riesgo en lesiones pre-neoplásicas en mujeres del sur de Chile: un estudio transversal / High-risk human papillomavirus detection and integration in preneoplastic lesions among women in Southern Chile: a cross-sectional study

INTRODUCCIÓN: El virus del papiloma humano de alto riesgo (VPH-AR) es responsable del cáncer de cuello uterino y sus lesiones preneoplásicas. Los genotipos VPH16 y VPH18 son los más frecuentes en este cáncer. La integración del VPH-AR en el genoma de la célula hospedera es crucial en la carcinogénesis cervical, pero la etapa en que ocurre en la población chilena es incierta. OBJETIVO: Evaluar la integración de VPH16 y VPH18 en lesiones pre-neoplásicas de cuello uterino. MÉTODOS: Se analizaron 108 muestras de raspados cervicales. El VPH se genotipificó mediante reacción de polimerasa en cadena (RPC) e hibridación no radiactiva. La integración de VPH16 y VPH18 se determinó por presencia del gen E2 mediante RPC. RESULTADOS: VPH16 y VPH18 se detectaron en 36,1% y 12,0% de las muestras, respectivamente. El VPH16 se integró en 23,1% de los casos de VPH16, mientras que VPH18 se integró en 100% de las muestras positivas para este genotipo. CONCLUSIONES: La integración VPH-AR es un evento temprano en la carcinogénesis cervical que ocurre en casi la mitad de las lesiones pre-neoplásicas y es más frecuente en VPH18 que en VPH16. La evaluación de la integración VPH-AR puede ser una herramienta útil para detectar el virus en la población chilena.

BACKGROUND: High-risk Human Papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer and its preneoplastic lesions. HPV16 and 18 are the most frequent HR-HPV genotypes detected in cervical cancer. HR-HPV genome integration into the host cell is an important event in the carcinogenic process. However, it remains uncertain which stage of cervical carcinogenesis HPV16 and 18 integration occurs in the Chilean population. AIM: The goal of this study was to evaluate HPV16 and HPV18 integration in preneoplastic lesions of the cervix. METHODS: DNA was extracted from 108 cervical scrape samples with preneoplastic lesions. HPV was genotyped using PCR and non-radioactive hybridization. The integration status of HPV16 and HPV 18 was determined by evaluating the E2 gene presence through PCR. RESULTS: HPV16 and HPV18 tested positive in 36.1% and 12.0% of samples, respectively. HPV16 was found integrated in 23.1% of HPV 16 cases, while HPV 18 in 100% of samples positive for this viral genotype. CONCLUSIONS: HR-HPV integration is an early event in cervical carcinogenesis, occurring in nearly half of preneoplastic lesions and being more frequent in HPV18 than in HPV16. The evaluation of HR-HPV integration can be utilized as a complementary tool for detecting HPV in the Chilean population.

An evaluation of carrier detection for Spinal muscular atrophy using digital PCR assay / 中华医学遗传学杂志

OBJECTIVE@#To assess the effectiveness and feasibility of carrier detection for Spinal muscular atrophy (SMA) by using digital PCR assay.@*METHODS@#Peripheral blood samples were collected from 214 pregnant women who were routinely screened for SMA carriers, of which 204 were randomly selected samples and 10 were samples with known copy numbers of SMN1 exons 7 and 8. Samples with known copy numbers of SMN1 exons 7 and 8 were randomly mixed into the experiment to validate the performance of the digital PCR assay.@*RESULTS@#The copy numbers of SMN1 exons 7 and 8 and SMN2 exons 7 and 8 in peripheral blood samples were detected by digital PCR assay. The results of SMN1 exons 7 and 8 were compared with those of the quantitative PCR method to assess the reliability and clinical performance of the digital PCR assay. Among the 204 random samples, digital PCR has detected five samples with simultaneous heterozygous deletion of SMN1 exons 7 and 8, three samples with heterozygous deletion of SMN1 exon 8 only, and 196 samples with no deletion of SMN1 exons 7 and 8. Ten samples with known SMN1 exons 7 and 8 copy numbers were detected with the expected values. The digital PCR test results were fully consistent with that of the quantitative PCR.@*CONCLUSION@#The results of digital PCR for the detection of copy number variation of SMN1 exons 7 and 8 were consistent with qPCR. Digital PCR assay was able to clearly distinguish the copy number of the target genes, therefore can be used for SMA carrier screening. Moreover, it can also detect copy number of SMN2 exons 7 and 8, which can provide more information for genetic counseling.

Complications following COVID-19 infection or vaccination in Libyan International Medical University students and their Families

Coronavirus disease 2019 (COVID-19) caused by a novel strain of coronavirus belonging to the genus Beta coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) emerged as a major pandemic worldwide. This contagious virus had spread in many different forms, and patients have demonstrated a wide range of symptoms, ranging from moderate to severe illness. This study aims to highlight the important associations between SARS-CoV-2 infection, vaccination, and possible complications at the Libyan International Medical University, Benghazi. This crosssectional survey was conducted among students and their families at Libyan International Medical University in Benghazi, Libya. Among the 100 participants, 72% were between the ages of 18 and 39. Up to (59%) of participants were men. As for the infection with COVID-19, 77% of participants were infected. Most of the participants had no chronic diseases (69%); however, the most common chronic disease was diabetes mellitus (13%). 82% of participants were vaccinated; the most common types of vaccines administered were Sinopharm and Sputnik V (24%). Following vaccination, 71% of participants had no COVID-19 infection, while 29% did get the infection. Regarding this study, after COVID-19 infection, 66% of participants had no complications; however, 17% had pulmonary complications, which was the most common complication among the participants. As for the complications following the vaccination, 81% of participants had none, while there were pulmonary and neurological complications in 7­6%. The results of the study showed that the most frequent complications noticed among the participants following the COVID-19 infection and vaccination were pulmonary and neurological complications.

Rendimiento diagnóstico de un sistema molecular de uso en el punto de atención para la detección de SARS-CoV-2 en Perú / Diagnostic performance of a point-of-care molecular system for the detection of SARS-CoV-2 in Peru

RESUMEN En el presente estudio se estimó el rendimiento diagnóstico de la prueba Xpert®Xpress SARS-CoV-2 en comparación con la RT PCR en tiempo real-protocolo Charité, para la detección de SARS-CoV-2 en pacientes peruanos. Se trató de un diseño de prueba diagnóstica que incluyó 100 muestras de hisopado nasal y faríngeo. Se obtuvo una concordancia global de 98,70% (IC95%: 92,98-99,97), con un coeficiente kappa de 0,97 (IC95%: 0,86-1.00); se estimó una sensibilidad y especificad relativa de 100% y 96,15%, respectivamente. Adicionalmente, el porcentaje del área bajo la curva ROC fue 98,08% en ambos casos y se obtuvo una especificidad analítica del 100% para los diferentes virus respiratorios evaluados. En conclusión, la prueba Xpert®Xpress SARS-CoV-2 a partir de muestras de hisopado nasal y faríngeo fue altamente sensible y específica, así mismo el coeficiente kappa mostró una excelente correlación, al compararla con la prueba de referencia.

ABSTRACT The present study assessed the diagnostic performance of the Xpert®Xpress SARS-CoV-2 test in comparison with the Charité protocol real-time RT PCR for the detection of SARS-CoV-2 in Peruvian patients. This was a diagnostic test study that included 100 nasal and pharyngeal swab samples. We obtained an overall concordance of 98.70% (95%CI: 92.98-99.97), with a kappa coefficient of 0.97 (95%CI: 0.86-1.00) and sensitivity and relative specificity rates of 100% and 96.15%, respectively. Additionally, the percentage of the area under the ROC curve was 98.08% in both cases, and an analytical specificity rate of 100% was obtained for the different respiratory viruses evaluated. In conclusion, the Xpert®Xpress SARS-CoV-2 test, by using nasal and pharyngeal swab samples, was highly sensitive and specific, and the kappa coefficient showed an excellent correlation when compared to the reference test.

Corneal transplantation and concomitant SARS-CoV-2 infection: a case report / Transplante de córnea e infecção concomitante por SARS-CoV-2: relato de caso

ABSTRACT This report was aimed at presenting a case of neurotrophic keratitis and concomitant SARS-CoV-2 infection in a patient who has recently undergone a corneal DALK transplant. One month after corneal transplantation with adequate corneal epithelialization, the patient presented neurotrophic keratitis with a torpid course of the corneal transplant coinciding with a SARS-CoV-2 infection, with an excessive host immune response. In addition, the patient presented a re-positivization of nasopharyngeal polymerase chain reaction of SARS-CoV-2 with past disease after starting treatment with autologous serum eye drops. The implications at the ophthalmological level of SARS-CoV-2 infection may be clarified as the time the illness progresses and we learn more about how it acts. In this case, the disparity of signs and symptoms, the antecedent of corneal surgery, and the possibility of a herpetic infection as a cause of the primary leukoma suggested neurotrophic keratitis. Nonetheless, the involvement of systemic SARS-CoV-2 infection in the process, triggering an excessive host immune response at the corneal level with an increase in inflammatory cytokines must be taken into account. No relationship was found between treatment with autologous serum and re-positivization of nasopharyngeal polymerase chain reaction, presenting the patient a favorable response to treatment.

RESUMO O objetivo deste relato foi apresentar um caso de ceratite neurotrófica e infecção concomitante por SARS-CoV-2 em paciente submetido recentemente a transplante de córnea DALK. Um mês após o transplante de córnea com adequada epitelização da córnea, o paciente apresentou ceratite neurotrófica com curso tórpido do transplante de córnea, coincidindo com infecção por SARS-CoV-2, com resposta imune excessiva do hospedeiro. Além disso, o paciente apresentou repositivização da reação em cadeia da polimerase nasofaríngeo de SARS-CoV-2, com doença pregressa após iniciar tratamento com colírio de soro autólogo. As implicações a nível oftalmológico da infecção por SARS-CoV-2, podem ser esclarecidas à medida que a doença progride e aprendemos mais sobre sua forma de atuação. Neste caso, a disparidade de sinais e sintomas, o antecedente de cirurgia de córnea e a possibilidade de infecção herpética como causa do leucoma primário sugeriram ceratite neurotrófica. No entanto, deve-se levar em consideração o envolvimento da infecção sistêmica por SARS-CoV-2 no processo, desencadeando uma resposta imune excessiva do hospedeiro no nível da córnea, com aumento de citocinas inflamatórias. Não foi encontrada relação entre o tratamento com soro autólogo e a repositivização da reação em cadeia da polimerase nasofaríngea, apresentando ao paciente uma resposta favorável ao tratamento.

Epidemiologia dos bocavirus humano em amostras fecais históricas no Brasil (1998-2005) / Epidemiology of human bocavirus in historical fecal samples in Brazil (1998-2005)

O bocavírus humano (HBoV) foi descrito pela primeira vez em 2005 e desde então associado como agente etiológico causador de doenças respiratórias e diarreia em todo mundo. Há 4 genótipos de HBoV identificados até o momento. HBoV-1 é comumente associado as infecções respiratórias, enquanto o HBoV-2, HBoV-3 e HBoV-4 são frequentemente detectados em amostras fecais. Coinfecções envolvendo o HBoV e outros agentes virais entéricos são frequentes. Vírus entéricos podem ser preservados em fezes congeladas por longos períodos. O objetivo do presente estudo foi investigar a frequência e a diversidade genotípica dos HBoV em amostras fecais históricas armazenadas e coletadas antes de 2005, a fim de compreender a história natural dos HBoV em pacientes com diarreia nas regiões Centro Oeste, Sul e Sudeste do Brasil. A associação do HBoV com outros vírus gastroentéricos de importância epidemiológica na doença diarreica também foi explorada. Um total de 3347 amostras foram selecionadas e testadas para HBoV por qPCR. As amostras positivas foram genotipadas por PCR convencional seguido de sequenciamento Sanger. As amostras positivas para HBoV por qPCR também foram testadas para a presença de Norovírus (NoV) por RT-qPCR e para Adenovirus Humano (HAdV) por PCR convencional e sequenciamento. HBoV foi detectado em 5,8% (195/3347). Coinfecção com NoV foi encontrada em 25,6% (50/195), HAdV 8,2% (16/195) e a tripla-infecção em 1% (2/195), totalizando 34,9% (68/195) de casos de coinfecções. Esses achados indicam que o HBoV pode ter um papel epidemiológico importante como único agente causador de doença diarreica em pacientes (65,2% de monoinfecções). A taxa de detecção variou significativamente de acordo com os anos de 2000-2001, 2002-2003 e 2003-2004 (p<0,05).

The human bocavirus (HBoV) was first described in 2005 and has since been associated as an etiological agent causing respiratory diseases and diarrhea worldwide. There are four genotypes of HBoV identified so far. HBoV-1 is commonly associated with respiratory infections, while HBoV-2, HBoV-3, and HBoV-4 are often detected in fecal samples. Coinfections involving HBoV and other enteric viral agents are common. Enteric viruses can be preserved in frozen feces for long periods. The aim of this study was to investigate the frequency and genotypic diversity of HBoV in stored historical fecal samples collected before 2005, in order to understand the natural history of HBoV in patients with diarrhea in the South and Southeast regions of Brazil. The association of HBoV with other gastroenteric viruses of epidemiological importance in diarrheal disease was also explored. A total of 3347 selected samples were tested for HBoV by qPCR. Positive samples were genotyped by conventional PCR followed by Sanger sequencing. Samples positive for HBoV by qPCR were also tested for the presence of Norovirus (NoV) by RT-qPCR and Human Adenovirus (HAdV) by conventional PCR and sequencing. HBoV was detected in 5.8% (195/3347) of samples. Coinfection with NoV was found in 25.6% (50/195), HAdV in 8.2% (16/195), and triple infection in 1% (2/195), totaling 34.9% (68/195) of coinfection cases. These findings indicate that HBoV may play an important epidemiological role as a single causative agent of diarrheal disease in patients (65.2% of monoinfections). The detection rate varied significantly according to the years 2000-2001, 2002-2003, and 2003-2004 (p<0.05), reinforcing that HBoV is an important pathogen in childhood diarrhea. The genotype was obtained in 32.8% (64/195) of positive HBoV samples, and genetic analysis identified the circulation of HBoV-1

Estudio del líquido cefalorraquídeo en pacientes con neoplasias hematológicas malignas / Study of cerebrospinal fluid in patients with hematologic malignancies

Introducción: La infiltración del sistema nervioso central por células malignas constituye una complicación grave de algunas neoplasias hematológicas, principalmente leucemias agudas y linfomas agresivos. Objetivo: Resumir la base científica y la significación clínica de los métodos de estudio del líquido cefalorraquídeo para el diagnóstico y el seguimiento de la infiltración neuromeníngea en pacientes con neoplasias hematológicas. Métodos: Se buscó información durante abril de 2021 en las bases de datos PubMed, ScienceDirect y SciELO. Se seleccionaron las publicaciones en base a su tipología, actualidad, alcance y las limitaciones de los estudios. Conclusiones: El estudio citomorfológico del líquido cefalorraquídeo se considera el método estándar para el diagnóstico y el seguimiento de la infiltración neuromeníngea. La citometría de flujo resulta más sensible para la detección de infiltración oculta que la citología convencional; pero aún existen reservas sobre su significación clínica. Se investiga también la sensibilidad de otros estudios moleculares como el uso de la reacción en cadena de la polimerasa y la detección de biomarcadores(AU)

Introduction: Infiltration of the central nervous system by malignant cells constitutes a serious complication of some hematological malignancies, mainly acute leukemias and aggressive lymphomas. Objective: To summarize the scientific basis and clinical significance of cerebrospinal fluid study methods for the diagnosis and follow-up of neuromeningeal infiltration in patients with hematologic malignancies. Methods: Information was searched during April 2021 in PubMed, ScienceDirect and SciELO databases. Publications were selected based on their typology, timeliness, scope, and study limitations. Conclusions: The cytomorphological study of cerebrospinal fluid is considered the standard method for the diagnosis and follow-up of neuromeningeal infiltration. Flow cytometry is more sensitive for the detection of occult infiltration than conventional cytology, but there are still reservations about its clinical significance. The sensitivity of other molecular studies such as the use of PCR and biomarker detection is also investigated(AU)

Genes resistentes a carbapenémicos y colistina aislados en Musca domestica proveniente de un basural cercano a un hospital de Lima / Carbapenems and colistin resistance genes isolated in Musca domestica from a garbage dump near a hospital in Lima

El objetivo fue determinar la presencia de genes de resistencia a carbapenémicos y resistencia plasmídica a colistina (mcr-1) en bacterias aisladas de Musca domestica en un basural cercano a un hospital de Lima, Perú. Las bacterias con resistencia fenotípica a los carbapénemicos se aislaron en medio CHROMagar mSu-perCARBATM y el perfil de resistencia a colistina se realizó mediante el método de elución de discos de co-listina. La detección de genes blaKPC, blaNDM, blaIMP, blaOXA-48, blaVIM y mcr-1 se realizó mediante PCR convencional. El perfil de susceptibilidad antimicrobiana se determinó mediante el sistema automati-zado MicroScan. Las bacterias con resistencia fenotípica a carbapenémicos fueron 31/38 cepas y a colistina fueron 26/38 cepas con una concentración inhibitoria mínima ≥ 4 µg/ml. Finalmente, se identificaron siete cepas bacterianas con genes de resistencia a carbapenémicos (OXA-48 Y KPC) y una cepa bacteriana con resistencia plasmídica a colistina (mcr-1). Una cepa de Escherichia coli presentó tres genes de resistencia: KPC, OXA-48 y mcr-1.

Programa de atención de vacunación contra el COVID-19 al personal del hospital de Huaycán / COVID-19 vaccination program for Huaycán hospital personnel / Programa de vacinação contra a COVID-19 para a equipe do hospital de Huaycán

A la fecha las vacunas para prevenir el COVID-19, representan la mejor esperanza para combatir el virus, además que éstas constituyeron un reto en la cadena de participación de reparto y distribución para las autoridades estatales en Perú, con respecto a priorizar dentro de la ciudadanía la adecuada administración por parte de quienes participaron en el proceso de vacunación. Objetivo. Analizar la gestión de la distribución y aplicación de la vacuna contra el COVID-19 en el Hospital de Huaycán. Materiales y Métodos. Se diseñó un estudio no experimental, de nivel aplicativo de enfoque cuantitativo, tipo de análisis descriptivo de corte transversal. La población estuvo conformada por 700 profesionales que laboran en dicho hospital. Las técnicas que fueron utilizadas fue la entrevista y la encuesta usando como instrumento un formulario de tipo cuestionario. Resultados. En cuanto a las medidas de prevención del virus en el personal de salud se realizaban pruebas diagnósticas a los trabajadores (pruebas rápidas y PCR) para identificar los casos sospechosos a un total de 2590 trabajadores, de los cuales 2372 se les realizó pruebas rápidas y 218 hisopados. En cuanto al nivel de ejecución de la vacunación se pudo determinar que totalidad de los trabajadores del Hospital de Huaycán, no alcanzaron a estar vacunados en el tiempo de aplicación de vacuna. Conclusiones. La gestión de la distribución y aplicación de la vacuna contra el COVID-19 en el Hospital de Huaycán revela una serie de aspectos tanto positivos como preocupantes. Si bien se observan indicadores de gestión adecuados en la administración de la vacuna, es evidente que la cobertura no ha alcanzado el 100%, lo cual implica retos en términos de alcance y eficacia de la inmunización en la población hospitalaria.

To date, vaccines to prevent COVID-19 represent the best hope for combating the virus, and they represent a challenge in the chain of distribution and distribution participation for state authorities in Peru, with respect to prioritizing the adequate administration by those who participated in the vaccination process among the citizens. Objective. To analyze the management of the distribution and application of the vaccine against COVID-19 in the Huaycán Hospital. Materials and Methods. A non-experimental study was designed, with a quantitative approach, descriptive cross-sectional analysis. The population consisted of 700 professionals working in the hospital. The techniques used were the interview and the survey using a questionnaire-type form as an instrument. Results. Regarding virus prevention measures in health personnel, diagnostic tests were performed on workers (rapid tests and PCR) to identify suspected cases in a total of 2,590 workers, of whom 2,372 underwent rapid tests and 218 swabs. As for the level of implementation of vaccination, it was determined that all the workers of the Hospital de Huaycán were not vaccinated at the time of vaccine application. Conclusions. The management of the distribution and application of the vaccine against COVID-19 in the Huaycán Hospital reveals a series of both positive and worrying aspects. Although adequate management indicators are observed in the administration of the vaccine, it is evident that coverage has not reached 100%, which implies challenges in terms of scope and efficacy of immunization in the hospital population.

Até o momento, as vacinas para prevenir a COVID-19 representam a melhor esperança para o combate ao vírus e têm representado um desafio na cadeia de participação na distribuição e distribuição para as autoridades estatais no Peru, com relação à priorização da administração adequada por parte dos envolvidos no processo de vacinação entre os cidadãos. Objetivo. Analisar a gestão da distribuição e aplicação da vacina contra a COVID-19 no Hospital Huaycán. Materiais e métodos. Foi projetado um estudo não experimental, com uma análise quantitativa, descritiva, transversal e transversal. A população foi composta por 700 profissionais que trabalham no hospital. As técnicas utilizadas foram entrevistas e pesquisas usando um formulário do tipo questionário como instrumento. Resultados. Em termos de medidas de prevenção do vírus entre o pessoal de saúde, foram realizados testes diagnósticos nos trabalhadores (testes rápidos e PCR) para identificar casos suspeitos em um total de 2.590 trabalhadores, dos quais 2.372 foram submetidos a testes rápidos e 218 a swabs. Em termos do nível de implementação da vacinação, foi determinado que todos os trabalhadores do Hospital Huaycán não foram vacinados dentro do período de vacinação. Conclusões. O gerenciamento da distribuição e aplicação da vacina contra a COVID-19 no Hospital Huaycán revela uma série de aspectos positivos e preocupantes. Embora sejam observados indicadores de gestão adequados na administração da vacina, é evidente que a cobertura não atingiu 100%, o que implica desafios em termos de alcance e eficácia da imunização na população do hospital.

Negativización de carga viral en pacientes positivos persistentes SARS-CoV-2 y uso de plasma de convalecientes / Negative viral load in persistent positive SARS-CoV-2 patients and use of convalescent plasma

No existe medicación específica contra el SARS-CoV-2 y el tratamiento consiste fundamentalmente en medidas de soporte. La transfusión de plasma de convalecientes consiste en administrar pasivamente anticuerpos policlonales, que generan una respuesta inmune inmediata y disminuyen la carga viral. El objetivo del estudio fue describir la estadía hospitalaria y negativización de reacción en cadena de la polimerasa en tiempo real en pacientes positivos persistentes con el uso de plasma de convalecientes. Se realizó un estudio descriptivo transversal, prospectivo, en 8 pacientes positivos persistentes que recibieron dicho plasma, en el Hospital Universitario Clínico Quirúrgico «Cmdte. Manuel Fajardo» de septiembre a noviembre de 2020. El mayor por ciento de casos necesitó una dosis de plasma de convalecientes para negativizar el PCR-TR. La estadía hospitalaria más frecuente fue de 14 a 19 días, el 62,50 % de los pacientes, 24 horas después de administrada la última dosis de este plasma, negativizó el RCP-TR evolutivo.

There is no specific medication against SARS-CoV-2 and the treatment consists mainly of supportive measures. Convalescent plasma transfusion consists of passively administered polyclonal antibodies, which generate an immediate immune response and decrease viral load. The objective of the study was to describe hospital stay and real-time polymerase chain reaction negativization in persistently positive patients with the use of convalescent plasma. A prospective, cross-sectional and descriptive study was carried out in 8 persistently positive patients who received such plasma at "Cmdte. Manuel Fajardo" Clinical and Surgical University Hospital from September to November 2020. The highest percentage of cases required a dose of convalescent plasma to make the RT-PCR negative. The most frequent hospital stay was from 14 to 19 days; 62.50% of the patients had a negative evolutionary RT-PCR, 24 hours after administering the last dose of this plasma.

Uso de PCR digital para definir terapéuticas específicas y seguimiento en enfermedades autoinflamatorias / Use of digital PCR to define specific therapeutics and follow-up in autoinflammatory diseases

Las enfermedades autoinflamatorias (AIDs) son un grupo heterogéneo de desórdenes monogénicos o poligénicos, con características de disregulación inmune innata y/o adaptativa, cuyo mecanismo central es la autoinflamación pero también pueden presentarse con autoinmunidad e inmunodeficiencia. En estos últimos años el desarrollo de las tecnologías de secuenciación masiva han provocado una explosión en el descubrimiento de nuevos genes responsables de AIDs monogénicas. Esto remarca la importancia de implementar este tipo de estudios para llegar a un diagnóstico definitivo sobre todo en este grupo de patologías genéticamente muy diversas donde los fenotipos clínicos se solapan. Sin embargo, dada la presencia de variantes de significación incierta (VUS), los resultados pueden no ser concluyentes planteándose la necesidad de desarrollar pruebas funcionales para determinar la patogenicidad de dichas variantes genéticas. En nuestro grupo de trabajo estamos aplicando la PCR digital en gotas (ddPCR), una técnica cuantitativa de 3era generación altamente sensible, especifica y reproducible que no necesita de curvas de calibración, para desarrollar pruebas funcionales que permitan no sólo reclasificar variantes VUS para lograr diagnósticos definitivos sino también estudiar los mecanismos responsables de las principales AIDs que permitan una estratificación de las terapéuticas especificas a aplicar y de esta manera poder contribuir al diagnóstico, tratamiento y seguimiento de nuestros pacientes en forma personalizada. (AU)

Autoinflammatory diseases (AIDs) are a heterogeneous group of monogenic or polygenic disorders, with characteristics of inborn and/or adaptive immune dysregulation, whose central mechanism is autoinflammation but may also present with autoimmunity and immunodeficiency. In recent years the development of massive sequencing technologies has led to an exponential increase in the discovery of new genes responsible for monogenic AIDs. This emphasizes the importance of the implementation of this type of studies to make a definitive diagnosis, especially in this group of genetically very diverse diseases with overlapping clinical phenotypes. However, given the presence of variants of uncertain significance (VUS), the results may not be conclusive, raising the need to develop functional tests to determine the pathogenicity of these genetic variants. In our working group we are applying droplet digital PCR (ddPCR), a highly sensitive, specific and reproducible third generation quantitative technique that does not require calibration curves, to develop functional tests that allow not only to reclassify VUS variants to achieve definitive diagnoses but also to study the mechanisms responsible for the main AIDs that allow for the stratification of specific treatments to be used and thereby contribute to the individualized diagnosis, treatment, and follow-up of our patients (AU)

Aplicación de PCR a partir de cultivo en la identificación de subespecies del complejo Mycobacterium Tuberculosis / The use of culture-based PCR for the identification of subspecies of the mycobacterium tuberculosis complex

Los métodos diagnósticos clásicos de tuberculosis (TB) se basan en la utilización de baciloscopía y cultivo. La identificación del agente etiológico desde la positivización del cultivo requiere entre 10 y 15 días, mientras que el empleo de la reacción en cadena de la polimerasa (PCR) disminuye el tiempo a 24 h, lo que permite no solo identificar las subespecies del complejo Mycobacterium tuberculosis (CMTB) sino también diferenciarlas de otras especies ambientales clínicamente importantes (MOTT) facilitando el diagnóstico y tratamiento. El objetivo del presente trabajo fue determinar la utilidad de la PCR en la identificación temprana de las micobacterias pertenecientes al CMTB, a partir de cultivos positivos, de pacientes con sospecha de TB, atendidos en un hospital pediátrico de alta complejidad, durante un período de cuatro años. A cada muestra, se le realizó baciloscopía y cultivo en medio líquido. A los cultivos positivos, una inmunocromatografía lateral (TBIDR) y luego PCR. El 4,6% del total de muestras (510/11.162) pertenecientes a 198 pacientes presentó cultivos positivos. Cuatrocientos veintiseis (84%) correspondieron a muestras respiratorias. El rendimiento de la baciloscopía directa fue del 41% (194/470). Cuatrocientos treinta y ocho (86%) resultaron M. tuberculosis, 21 (4%) Mycobacterium bovis, 7 (1%), M. bovis-BCG y 44 (9%) MOTT. La utilización de medios de cultivos líquidos junto con el empleo de PCR favorecen una rápida orientación microbiológica y constituye una estrategia útil para optimizar el manejo clínico de estas infecciones, desde el punto de vista terapéutico y epidemiológico, especialmente en pediatría (AU)

Classical diagnostic methods for tuberculosis (TB) are based on the use of smear microscopy and culture. The identification of the etiological agent from positive culture requires 10 to 15 days, while the use of the polymerase chain reaction (PCR) reduces the time to 24 h, which allows not only to identify the subspecies of the Mycobacterium tuberculosis complex (MTC) but also to differentiate them from clinically important environmental mycobacteria other than tuberculosis (MOTT), facilitating diagnosis and treatment. The aim of this study was to determine the usefulness of PCR in the early identification of mycobacteria belonging to the MTC, from positive cultures of patients with suspected TB seen in a pediatric tertiary hospital over a 4-year period. For each sample, smear microscopy and culture in liquid medium was performed. Positive cultures were subjected to lateral immunochromatography (TBIDR) and then PCR. Of the total number of samples (510/11,162) belonging to 198 patients, 4.6% showed positive cultures; 426 (84%) were respiratory samples. The direct smear microscopy yield was 41% (194/470). Overall, 438 (86%) were found to be M. tuberculosis, 21 (4%) Mycobacterium bovis, 7 (1%), M. bovis-BCG, and 44 (9%) MOTT. The use of liquid culture media together with the use of PCR favors a rapid microbiological orientation and is a useful strategy to optimize the clinical management of these infections, from a therapeutic and epidemiological point of view, especially in children (AU)

Performance of the tetra-primer PCR technique compared to PCR-RFLP in the search for rs12979860 (C/T) and rs8099917 (T/G) single nucleotide polymorphisms (SNPs) in the IFNL4 gene / Desempenho da técnica tetra-primer PCR em relação a PCR-RFLP na pesquisa de polimorfismos de nucleotídeos únicos (SNPs) rs12979860 (C/T) e rs8099917 (T/G) no gene IFNL4

Single nucleotide polymorphisms (SNPs, rs12979860 e rs8099917) in the Interferon Lambda 4 gene (IFNL4, formerly IFNL3and/or IL28B) has been associated with failure in the innate immune response, sustained virological response in hepatitis C, and HTLV-1-associated myelopathy (HAM) development. To search for these polymorphisms several methodologies can be employed, such as sequencing, real-time or quantitative polymerase chain reaction (qPCR), restriction fragment length polymorphism analysis in PCR products (PCR-RFLP), and tetra-primer PCR. The present study compared the performance of the tetra-primer PCR in relation to the PCR-RFLP, both optimized in the Research HTLV Laboratory of the Center of Immunology of Instituto Adolfo Lutz in São Paulo. One hundred DNA samples obtained from patients of STD/Aids Reference Centre in São Paulo, previously analyzed for IL28B SNPs by PCR-RFLP were selected for analysis, after confirming that they represent all IL28B SNPs patterns described in the literature. The results obtained showed concordance between the PCR-RFLP and the tetra-primer PCR SNPs results, and because of the low cost, easy to perform, and minor employment of biological specimen and reagents, the tetra-primer PCR is of choice to be used in routine. (AU)

Polimorfismos de nucleotídeos únicos (single nucleotide polymorphisms, SNPs rs12979860 e rs8099917) no gene que codifica o Interferon Lambda 4 (IFNL4, antigamente IFNL3 e/ou IL28B) têm sido associados às falhas na resposta imune inata e resposta virológica sustentada na hepatite C, e a mielopatia associada ao HTLV-1 (HTLV-1-associated myelopathy, HAM). A pesquisa destes polimorfismos pode empregar diversas metodologias: sequenciamento, reação em cadeia da polimerase em tempo real ou quantitativa (quantitative polymerase chain reaction, qPCR), análise de fragmentos de restrição enzimática em produtos de PCR (restriction fragment length polymorphism in PCR products, PCR-RFLP) e a tetra-primer PCR. Este estudo comparou o desempenho da tetra-primer PCR em relação a PCR-RFLP, ambas otimizadas no Laboratório de Pesquisa em HTLV do Centro de Imunologia do Instituto Adolfo Lutz de São Paulo. Foram selecionadas 100 amostras de DNA obtidas de pacientes do Centro de Referência e Treinamento em DST/Aids de São Paulo cujos SNPs na IL28B foram anteriormente determinados por PCR-RFLP e representaram todos os perfis descritos em literatura. Os resultados obtidos mostraram concordância entre elas, e pelo fato da tetra-primer PCR ter menor custo, ser de fácil execução, empregar menos tempo, insumos e material biológico, é a técnica de escolha para uso em rotina. (AU)

Meningitis por Listeria: serie de casos en un hospital de tercer nivel y utilidad de las nuevas técnicas de diagnóstico microbiológico / Listeria meningitis: case series in a tertiary level hospital and the usefulness of new microbiological diagnostic techniques

Introducción: La meningitis por Listeria monocytogenes (MLM) es una entidad grave con complicaciones a corto plazo. La reacción de polimerasa en cadena (RPC) puede ayudar a mejorar su diagnóstico y pronóstico. Objetivos: Conocer las características de los pacientes diagnosticados de meningitis por L. monocytogenes en los últimos años, a través de diferentes métodos microbiológicos. Pacientes y Métodos: Serie de casos de pacientes adultos ingresados con MLM en el Hospital Clínico San Carlos, Madrid, España, durante doce años (2009-2021). Se describieron variables epidemiológicas, clínicas, microbiológicas, radiológicas y terapéuticas. Resultados: Se registraron doce pacientes con MLM (edad media 67,5 años, 75% varones). En ocho se obtuvo un cultivo positivo a L. monocytogenes. La RPC en líquido cefalorraquídeo (LCR) fue positiva en los dos casos en los que se realizó la prueba. El tratamiento dirigido en todos los casos fue ampicilina durante 21 días. Se registraron complicaciones en un cuarto de los casos. Del total de pacientes uno falleció. Conclusiones: La MLM es una enfermedad poco frecuente y de difícil diagnóstico. En nuestra serie de casos los dos pacientes diagnosticados por RPC tuvieron resultado de cultivo de LCR negativo, y presentaron buena evolución. La determinación de RPC podría permitir diagnosticar un mayor número de casos y con mayor precocidad.

Background: Listeria monocytogenes meningitis (LMM) is a serious entity with short-term complications. Polymerase chain reaction (PCR) can help to improve its diagnosis and prognosis. Aim: To know the characteristics of patients diagnosed with meningitis by L. monocytogenes in recent years, through different microbiological methods. Methods: Case series of adult patients admitted with LMM at the Hospital Clínico San Carlos of Madrid, Spain, during twelve years (2009-2021). Epidemiological, clinical, microbiological, radiological and therapeutic variables were described. Results: Twelve patients with LMM were recorded (mean age 67.5 years, 75% male). Eight had a positive culture for L. monocytogenes. cerebrospinal fluid (CSF) PCR was positive in the two cases in which the test was performed. Treatment in all cases was ampicillin for 21 days. Complications were recorded in a quarter of the cases. One patient died. Conclusions: LMM is a rare and difficult to diagnose disease. In our series of cases, the two patients diagnosed by PCR had negative CSF culture results, and presented good evolution. PCR determination could allow a greater number of cases to be diagnosed earlier.

Síndrome urémico hemolítico del adulto / Adult hemolytic uremic syndrome

El síndrome urémico hemolítico (SUH), descripto en 1955, se caracteriza por la tríada de anemia hemolítica no inmunomediada, trombocitopenia y lesión renal aguda. En su patogenia interviene la toxina Shiga, producida con mayor frecuencia por E. coli O157:H. Puede manifestarse a cualquier edad, aunque es infrecuente en adultos, y se desarrolla en forma esporádica o en brote. Se presenta con un cuadro de dolor abdominal, diarrea, fiebre y vómitos. Puede afectar el sistema nervioso central, pulmones, páncreas y corazón. En adultos, el síndrome evoluciona tras un período de incubación de 1 semana posterior a la diarrea y tiene alta morbimortalidad, a diferencia de los casos pediátricos. Presentamos el caso de una paciente adulta, que cursó internación por síndrome urémico hemolítico. (AU)

Hemolytic uremic syndrome (HUS), described in 1955, is characterized by the triad of non-immune mediated hemolytic anemia, thrombocytopenia, and acute kidney injury. Shiga toxin, produced most frequently by E coli O157:H, is involved in its pathogenesis. Hus can manifest at any age, although it is rare in adults and develops sporadically or in outbreaks. HUS presents with a picture of abdominal pain, diarrhea, fever and vomiting. It can affect the central nervous system, lungs, pancreas, and heart.In adults, the syndrome evolves after an incubation period of 1 week after diarrhea, with high morbidity and mortality, unlike pediatric cases.We present the case of an adult patient who was hospitalized for hemolytic uremic syndrome. (AU)

Identification of antarctic soil bacteria exhibiting antiproliferative activity against a colon cancer cell line / Identificación de bacterias de suelo antártico que presentan actividad antiproliferativa sobre una línea celular de cáncer de colon

SUMMARY: Cancer is the second leading cause of death in the world and colorectal cancer is the only cancer that has shown a sustained increase in mortality in the last decade. In the search for new chemotherapeutic agents against cancer, extremophilic microorganisms have shown to be a potential source to obtain molecules of natural origin and with selective cytotoxic action towards cancer cells. In this work we analyzed the ability of a collection of Antarctic soil bacteria, isolated on Collins Glacier from the rhizosphere of Deschampsia antarctica Desv plant, to secrete molecules capable of inhibiting cell proliferation of a colorectal cancer tumor line. Our results demonstrated that culture supernatants from the Antarctic bacteria K2I17 and MI12 decreased the viability of LoVo cells, a colorectal adenocarcinoma cell line. Phenotypic and genotypic characterization of the Antarctic bacteria showed that they were taxonomically related and nucleotide identity analysis based on the 16S rRNA gene sequence identified the bacterium K2I17 as a species belonging to the genus Bacillus.

El cáncer es la segunda causa de muerte en el mundo y el cáncer colorrectal es el único que presenta un aumento sostenido de la mortalidad en la última década. En la búsqueda de nuevos agentes quimioterapeúticos contra el cáncer, se ha propuesto a los microorganismos extremófilos como una fuente potencial para obtener moléculas de origen natural y con acción citotóxica selectiva hacia las células cancerígenas. En este trabajo analizamos la capacidad de una colección de bacterias de suelo antártico, aisladas en el glaciar Collins desde rizosfera de la planta de Deschampsia antarctica Desv, de secretar moléculas capaces de inhibir la proliferación celular de una línea tumoral de cáncer colorrectal. Nuestros resultados demostraron que los sobrenadantes de cultivo de las bacterias antárticas K2I17 y MI12 disminuyeron la viabilidad de la línea celular de adenocarcinoma colorrectal LoVo, en un ensayo de reducción metabólica de MTT. La caracterización fenotípica y genotípica de las bacterias antárticas, demostró que estaban relacionadas taxonómicamente y el análisis de la identidad nucleotídica en base a la secuencia del gen ARNr 16S identificó a la bacteria K2I17 como una especie perteneciente al género Bacillus.