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Stopping the spread of coronavirus disease 2019 (COVID-19) is critical and can be achieved through rapid and effective detection techniques. Our objective was to compare the diagnostic accuracy of rapid antigen tests (RAgT) and reverse transcriptionquantitative polymerase chain reaction (RT-qPCR) and to describe amplification cycle thresholds (Cts). Participants were children aged 1 month to 11 years with symptoms for less than 7 days, who did not have a detectable result in the past 90 days, and were immunocompetent. A total of 1855 patients were included; the prevalence of COVID-19 was 4.7%. For the RAgT, overall sensitivity was 60.2% and specificity, 99.8%; in children older than 5 years, values were 69.8% and 99.8%, respectively. Ct values for discordant samples were higher. To conclude, the diagnostic accuracy indicated that the specificity of RAgT is similar to that of RT-qPCR, but its sensitivity is notably lower, especially in children younger than 5 years.Frenar la propagación de la enfermedad por el coronavirus 2019 (COVID-19, por su sigla en inglés) es fundamental, y se puede realizar mediante técnicas de detección rápidas y efectivas. El objetivo fue comparar la precisión diagnóstica de un test rápido de antígeno (TRAg,) con la reacción en cadena de polimerasa con retrotranscripción (RT-qPCR, por su sigla en inglés) y describir los umbrales de amplificación (Ct, por su sigla en inglés). Participaron niños de 1 mes a 11 años que tuvieran menos de 7 días de síntomas, sin resultado detectable en los últimos 90 días, e inmunocompetentes. Se incluyeron 1855 pacientes con una prevalencia de COVID-19 del 4,7 %. La sensibilidad global del TRAg fue del 60,2 % y su especificidad, del 99,8 %; en niños mayores de 5 años los valores fueron de 69,8 % y 99,8 %, respectivamente. Los valores de Ct de las muestras discordantes fueron más altos. En conclusión, la precisión diagnóstica muestra que TRAg tiene una especificidad similar a la RT-qPCR, pero una sensibilidad considerablemente menor, sobre todo en niños de menos de 5 años.

Molecular surveillance of SARS-CoV-2 variants was performed on a total of 2,406 samples from the capital city and nine provinces of Argentina, during 30 epidemiological weeks (EW) that covered the end of the first wave and the beginning of the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 20/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the simultaneous identification of signature mutations associated with worldwide circulating variants. In addition, whole SARS-CoV-2 genome sequences were obtained from 456 samples. The main variants found were Gamma, Lambda and Alpha, and to a lesser extent, Zeta and Epsilon. Whereas Gamma dominated in different regions of the country, both Gamma and Lambda prevailed in the most populated area, the metropolitan region of Buenos Aires (MABA), although showing a heterogeneous distribution along this region. This cost-effective surveillance protocol allowed for a rapid response in a limited access to resources scenario, added information on the expansion of the Lambda variant in South America and contributed to the implementation of public health measures to control the disease spread in Argentina.

Alpha-1 antitrypsin (AAT) deficiency is one of the most common inherited disorders with a higher incidence in patients with chronic obstructive pulmonary disease (COPD). Its prevalence in patients with spontaneous pneumothorax is unknown. The objective was to estimate the prevalence of AAT deficiency in patients with spontaneous pneumothorax. This was a prospective cross-sectional study, in patients with spontaneous pneumothorax, where those with secondary pneumothorax were excluded. Quantification of serum AAT by nephelometry and subsequent rapid genotyping (real time PCR) was performed, in order to detect the most prevalent deficiency alleles (Z and S) in those subjects with serum AAT concentrations = 120 mg/dl. Fifty-eight patients with primary spontaneous pneumothorax were included. The average age was 34 ± 13 years with male predominance (72%) and high prevalence of current and past smoking (60%). Twenty six percent of them (95% CI: 15-39) presented AAT serum concentrations = 120mg/dl. We found 7 deficiency variants (12%; IC 95%: 5-23%). One patient presented a severe Pi•ZZ form (1.7%), 3 were heterozygotes Z (5.2%) and 3 heterozygotes S (5.2%). The prevalence of AAT deficient variants was high in patients with spontaneous pneumothorax.La deficiencia de alfa-1 antitripsina (AAT) es uno de los trastornos hereditarios más frecuentes y con mayor incidencia en pacientes con enfermedad pulmonar obstructiva crónica (EPOC). Se desconoce su prevalencia en aquellos con neumotórax espontáneo. El objetivo fue estimar la prevalencia de deficiencia de AAT en sujetos con neumotórax espontáneo. El estudio fue prospectivo y de corte transversal en pacientes con neumotórax espontáneo primario. Se excluyeron aquellos con neumotórax secundario. Se realizó cuantificación de AAT en suero por nefelometría y posterior genotipificación rápida (PCR en tiempo real) para detectar los alelos de deficiencia más prevalentes (Z y S) en aquellos con concentraciones séricas = 120 mg/dl. Se incluyeron 58 pacientes con neumotórax espontáneo primario. La edad promedio fue de 34 ± 13 años con predominio de sexo masculino (72%) y alta prevalencia de tabaquismo actual y pasado (60%). Del total, el 26% (IC95%: 15-39) presentó concentraciones de AAT = 120mg/dl. Encontramos 7 formas deficitarias (12%; IC 95%: 5-23%). Un paciente presentó una forma grave Pi•ZZ (1.7%), 3 fueron heterocigotos Z (5.2%) y 3 heterocigotos S (5.2%). La prevalencia de variantes deficitarias de AAT fue alta en este grupo con neumotórax espontáneo.

Background: Persistent airflow limitation is common among patients with severe asthma, but its pathogenesis has not been fully clarified. Severe alpha-1-antitrypsin deficiency (AATD) is a risk factor for chronic airflow limitation and emphysema, and partially deficient phenotypes have been associated with an accelerated decline in lung function. Aims: To estimate frequency of AATD in patients with persistent airflow limitation in severe asthma. Methods: 207 patients with severe asthma and persistent airflow limitation (FEV1 All patients underwent determination of serum AAT levels by nephelometry. In those patients with serum levels under 120 mg/dL an allele specific genotyping assay was performed to detect the most prevalent variants (Z and S). Statistical analysis was made with PAWS Statistics 18 © software. Results: We found female predominance (64.2%), mean age: 56 years (range 23-70), 14.5% of active smokers, Mean alpha-1 antitrypsin was 137 mg/dL. Genotyping assay was made in 20.2% samples that were under cut-off. Deficient patients MZ=3 (1.45%), SS=1 (0.49%), and MS=12 (5.79%). Conclusions: Prevalence of AATD in patients with severe asthma and airflow limitation is low. Routine assessment of AATD is not supported by this data therefore further studies are needed.

Alpha-1 antitrypsin (AAT) genotyping is useful to confirm the clinical diagnosis of AAT deficiency and determine the specific allelic variant. Genotyping is the reference standard procedure for identifying rare allelic variants and characterizing new variants. It is also useful when there is a discrepancy between the patients' AAT levels and their phenotypes. AAT genotype is determined by an allele-specific genotyping assay for the S, Z, and Mmalton variants and by exome sequencing.

Alpha-1 antitrypsin (AAT) genotyping is useful to confirm the clinical diagnosis of AAT deficiency and determine the specific allelic variant. Genotyping is the reference standard procedure for identifying rare allelic variants and characterizing new variants. It is also useful when there is a discrepancy between the patients' AAT levels and their phenotypes. AAT genotype is determined by an allele-specific genotyping assay for the S, Z, and Mmalton variants and by exome sequencing.

Background: α1-Antitrypsin deficiency (AATD) is an autosomal codominant disorder associated with a high risk of developing lung and liver disease. The most common deficient alleles are known as Z and S. However, another deficient variant, called Mmalton, which causes a deficiency similar to variant Z, is considered to be the second cause of severe AATD in Spain. Nevertheless, the Mmalton allele is not recognizable by usual diagnostic techniques and therefore, its real prevalence is underestimated. We describe a rapid real-time PCR and melting curves assay designed for the detection of Mmalton AATD. Methods: we tested the applicability of this new technique for the identification of the Mmalton allele in AATD screening using whole blood, dried blood spot (DBS) and serum samples. Mmalton heterozygote and homozygote samples and samples without this allele were included in the study. Results: this new assay is able to detect homozygous and heterozygous genotypes in the same reaction and in a single step, giving matching results with those obtained by SERPINA1 gene sequencing. Conclusions: this technology is optimal for working with small amounts of DNA, such as in DBS and even with residual DNA present in serum samples, allowing improvement in routine algorithms of AATD diagnosis or large-scale screening. This method will be useful for obtaining more in depth knowledge of the real incidence of the Mmalton variant.

The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throµgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sµggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.