Microascus gracilis y otomicosis / Microascus gracilis and otomycosis

Microascus spp, teleomorfo de Scopulariopsis, es un hongo saprofito encontrado normalmente en suelo, alimentos, vegetales e incluso en ambientes interiores. Considerado un contaminante ambiental, se caracteriza por la resistencia intrínseca a los antifúngicos disponibles. Existen escasas referencias de infecciones por Microascus gracilis, asociándose como causa de eumicetoma o enfermedad diseminada en pacientes sometidos a trasplante pulmonar. Presentamos un caso de otomicosis por M. gracilis con el fin de considerar la búsqueda de hongos en los cultivos óticos y poner de relevancia el poder patógeno y colonizador de este agente.

Microascus spp, a teleomorph of Scopulariopsis, is a saprophytic fungus normally found in soil, food, vegetables, and even indoors. Considered an environmental pollutant, it is characterized by its intrinsic resistance to available antifungals. There are few references to infections by Microascus gracilis, associating it as a cause of eumycetoma or disseminated disease in lung transplant recipients. We present a case of otomycosis caused by M. gracilis, to consider the search for fungi in ear cultures and highlight the pathogenic and colonizing power of this agent.

Sample Pooling as an efficient strategy for SARS-COV-2 RT-PCR screening: a multicenter study in Spain

ImportanceThe actual demand on SARS-CoV-2 diagnosis is a current challenge for clinical laboratories. Sample pooling may help to ameliorate workload in clinical laboratories. Objectiveto evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of CoVID-19, by using different commercial platforms for nucleic acid extraction and amplification. Design and settingsobservational, prospective, multicentre study across 9 Spanish clinical microbiology laboratories including SARS-CoV-2 RNA testing performed in April 2020, during the first three days after acceptance to participate. Participants and Methods3519 naso-oro-pharyngeal samples received at the participating laboratories were processed individually and in pools (351 pools) according to the existing methodology in each of the centres. ResultsWe found that 253 pools (2519 samples) were negative, and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples) we found discordant results when compared to their correspondent individual samples: in 24/29 pools (30 samples), minor discordances were found; for five pools (5 samples), we found major discordances. Sensitivity, specificity, positive and negative predictive values for pooling were 97.93%, 100%, 100% and 99.85% respectively; accuracy was 99.86% and kappa concordant coefficient was 0.988. As a result of the sample dilution effect of pooling, a loss of 2-3 Cts was observed for E, N or RdRP genes. Conclusionwe show a high efficiency of pooling strategies for SARS-CoV-2 RNA testing, across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity, and positive and negative predictive values. We believe that our results may help clinical laboratories to respond to the actual demand and clinical need on SARS-CoV-2 testing, especially for the screening of low prevalence populations. Key points QuestionMay clinical laboratories implement sample pooling as an efficient and safe strategy for SARS-COV-2 RT-PCR screening? FindingsSensitivity, specificity, positive and negative predictive values for pooling were 97.93%, 100%, 100% and 99.85% respectively; accuracy was 99.86% and kappa concordant coefficient was 0.988. MeaningSample pooling can be used safely at clinical laboratories, especially for the screening of low prevalence populations.