Seroprevalence of Anti-SARS-CoV-2 Antibodies in Blood Donors from Nuevo Leon State, Mexico, during 2020: A Retrospective Cross-Sectional Evaluation.

The progression and distribution of the SARS-CoV-2 pandemic are continuously changing over time and can be traced by blood donors' serological survey. Here, we investigated the seroprevalence of anti-SARS-CoV-2 antibodies in blood donors in Nuevo Leon, Mexico during 2020 as a strategy for the rapid evaluation of the spread of SARS-CoV-2 and asymptomatic case detection. We collected residual plasma samples from blood donors who attended two regional donation centers from January to December of 2020 to identify changes in anti-SARS-CoV-2 IgG prevalence. Plasma samples were analyzed on the Abbott Architect instrument using the commercial Abbott SARS-CoV-2 IgG chemiluminescent assay. We found a total of 99 reactive samples from 2068 analyzed plasma samples, resulting in a raw prevalence of 4.87%. Donors aged 18-49 years were more likely to be seropositive compared to those aged >50 years (p < 0.001). Weekly seroprevalence increased from 1.8% during the early pandemic stage to 27.59% by the end of the year. Prevalence was 1.46-fold higher in females compared to males. Case geographical mapping showed that Monterrey city recorded the majority of SARS-CoV-2 cases. These results show that there is a growing trend of seroprevalence over time associated with asymptomatic infection that is unnoticed under the current epidemiological surveillance protocols.

Assessment of software-derived predictive algorithms for platelet yield and blood cell count after apheresis.

INTRODUCTION: Algorithms have been developed to predict the platelet yield after apheresis from the donor's data, as well as the effect on the blood cell count, to extract an acceptable platelet number without affecting the donor. However, the evaluation of these algorithms has not been widely reported. This study aimed to assess the accuracy of the predictive algorithms of the Trima Accel v. 6 blood collection system. METHODS: Platelet concentrates (PCs) obtained by apheresis were analyzed. Platelet count and hematocrit were compared pre- and post-apheresis. Calculated post-apheresis platelet count (CPAPC), hematocrit (CPAH), and platelet yield (CPY), and their actual values were correlated. The bias of the algorithms was assessed with Bland-Altman plots, and the prediction of the extraction of single or double platelet products was evaluated. RESULTS: Two hundred and seventy-nine PCs were analyzed. Post-apheresis platelet count (PAPC) and hematocrit were decreased. A moderate correlation was observed between CPY and the actual yield, with a negative bias, and a trend to increase alongside the magnitude of the measurements. CPAPC and CPAH were strongly correlated with their actual values without bias. Prediction of single or double platelet product extraction showed a significant agreement with the actual outcomes. CONCLUSIONS: The predictive algorithm for the platelet yield showed bias, and a trend to underestimate the actual platelet yields when they are higher. The algorithms for the prediction of the PAPC and hematocrit did not show bias, proving their accuracy. Prediction of a single or double platelet product extraction has a strong agreement with the APY.

Donor platelet and leukocyte count as predictive factors of the quality of platelet concentrates obtained from whole blood by semiautomated fractionation.

Platelet concentrates (PCs) obtained from whole blood are produced by fractionation of the buffy coat (BC) or the platelet-rich plasma. Despite the improvements in the technologies used for the hemocomponent fractionation, the proportion of PCs that do not accomplish the quality requirements is high. This study aimed to determine whether the basal platelet and leukocyte counts are predictive factors of the quality of the PCs obtained from BC by semiautomated fractionation. Quality control registers of 196 PCs were analyzed. Gender- and age-dependence of the blood cell count and the characteristics of PCs were evaluated. Platelet yield and residual leukocytes in the PCs were correlated with the platelet and leukocyte counts and the age of the donors. Predictive efficacy was assessed, and an optimal cut-off was established. The proportions of PCs accepted and rejected by using or not the optimal cut-off were compared. 50.0% of the PCs accomplished all the quality control requirements. Female donors had a higher basal platelet count than males. A correlation was observed between basal platelets and platelet yield, but not between basal leukocytes and residual leukocytes. The basal platelet count predicted the quality of the PCs. A cut-off of 231,000 platelets/mm3 was established, but it did not improve the proportion of accepted PCs. In conclusion, we found that the basal platelet count is correlated with the platelet yield. The basal leukocyte count is not correlated with the residual leukocytes. The established cut-off for the basal platelet count did not improve the proportion of accepted PCs.

Serological screening in donors in Mexico: advances and technology / Tamizaje serológico en donadores de México: avances y tecnología

The residual risk of transfusion-related infections has decreased dramatically in countries that have routinely implemented serological screening. Most of the donation in Mexico is from replacement practice, a risk factor for positive serology. In Mexico, the altruistic donation is only 2.7%. The heterogeneity of technical factors, regional factors and internal policies of each center influences the variability of data on the prevalence of positive screening, as well as the prevalence of confirmed cases. The main advantage of nucleic acid technology is the detection of donors in the period of serological window or occult infections, being occult hepatitis reports in Mexican donors from 1 to 3.4%. The limitation of available technology, the scope of the clinic and perspectives, invites us to improve technology and health policies in the interest of transfusion safety.

El riesgo residual de las infecciones relacionadas a la transfusión ha disminuido drásticamente en los países que han implementado rutinariamente el tamizaje serológico. La mayor parte de la donación en México es de reposición, factor de riesgo para serología positiva, y en donde la donación altruista es de apenas 2.7%. La heterogeneidad de factores técnicos, regionales y políticas internas de cada centro influyen en la variabilidad de datos en prevalencia del tamizaje positivo, así como en la prevalencia de casos confirmados. La principal ventaja de la tecnología de ácidos nucleicos es la detección de donadores en periodo de ventana serológico o de infecciones ocultas, con reportes de hepatitis ocultas en donadores de 1-3.4% en México. Las limitantes de la tecnología disponible, el alcance de la clínica y de las perspectivas, nos invita a la mejora tecnológica y de las políticas sanitarias en aras de la seguridad transfusional.

Microbiology of genus Raoultella, clinical features and difficulties in its diagnosis / Microbiología del género Raoultella, características clínicas y dificultades para su diagnóstico

The genus Raoultella, which belongs to the Enterobacteriaceae family, encompasses gramnegative, oxidase-negative, aerobic, encapsulated and motionless bacilli. Currently, four species of this genus have been described: Raoultella terrigena (R. terrigena), Raoultella planticola (R. planticola), Raoultella ornithinolytica (R. ornithinolytica) and Raoultella electrica (R. electrica), out of which R. planticola and R. ornithinolytica are the most important because of their probable association as pathogenic agents. The incidence of this genus has been underestimated, given that detecting it is really difficult, since it is misidentified as Klebsiella spp. by using manual and automated conventional phenotypic methods. The rapid and correct detection has been increasing since the advent of mass spectrometers (MALDI-TOF MS), which have been used for the differentiation of Klebsiella spp. and Raoultella spp. Currently 80 cases of bacteremia secondary to Raoultella spp. have been identified with different sites of primary infection, which is why it is important to emphasize proper detection in hospitals and healthcare facilities.

El género Raoultella, perteneciente a la familia Enterobacteriaceae, engloba bacilos gram negativos, oxidasa negativos, aeróbicos, encapsulados e inmóviles. Actualmente se han descrito cuatro especies de este género: Raoultella terrigena (R. terrigena), Raoultella planticola (R. planticola), Raoultella ornithinolytica (R. ornithinolytica) y Raoultella electrica (R. electrica), entre las que la R. planticola y la R. ornithinolytica son las más importantes por su probable asociación como agentes patógenos. Se ha subestimado la incidencia del género por la dificultad que presenta su caracterización al ser mal identificado como Klebsiella spp., al usar métodos fenotípicos manuales y automatizados convencionales. La rápida y correcta detección de Raoultella spp. ha ido aumentando desde la llegada de espectrómetros de masas (MALDI-TOF MS), útiles en la diferenciación entre Klebsiella spp. y Raoultella spp. Se han identificado 80 casos de bacteremia por Raoultella spp., con infección primaria en diversos sitios, por lo que es importante hacer énfasis en su correcta detección en los hospitales y centros de atención médica.

Efficacy and safety evaluation of systemic extremely low frequency magnetic fields used in the healing of diabetic foot ulcers--phase II data.

BACKGROUND AND AIMS: Cellular and animal models investigating extremely low frequency magnetic fields (ELF-MF) have reported promotion of leukocyte-endothelial interactions, angiogenesis, myofibroblast and keratinocyte proliferation, improvement of peripheral neuropathy and diabetic wound healing. In humans, it has also been reported that systemic exposure to ELF-MF stimulates peripheral blood mononuclear cells, promoting angiogenesis and healing of chronic leg ulcers. The aim of the study was to investigate the effect of exposing different blood volumes to specific ELF-MFs (120 Hz sinusoidal waves of 0.4-0.9 mT RMS) to induce healing of diabetic foot ulcers (DFUs). METHODS: Twenty six diabetic patients with non-responsive DFUs were divided into two exposure groups to receive treatment and record healing time. The forearm group, exposed to ELF-MF 2 h/day, twice weekly (3.6 l of blood/session); and the thorax group, exposed 25 min/day, 2 times/week (162.5 l of blood/session). Treatment period was 100 days or upon complete healing. Ulcer recurrences and adverse effects were investigated during short-term (<1 year) and long-term (3.4-7.8 years) follow-up. RESULTS: Mean healing time was 61.48 ± 33.08 days in the forearm group and 62.56 ± 29.33 days for the thorax group. No adverse effects or ulcer recurrences in the original ulcer site were reported during treatment, the short-term follow-up period or the long-term follow-up period in both groups. CONCLUSIONS: Healing time was independent of the amount of blood exposed to ELF-MF used in this trial. ELF-MFs are effective and safe and could be applied to non-healing DFUs in conjunction with other preventive interventions to reduce DFUs complications.

[Comparative study of a rapid testing with real time RT-PCR for diagnosis of influenza AH1N1 2009]. / Estudio comparativo entre una prueba rápida y RT-PCR tiempo real en el diagnóstico de influenza AH1N1 2009.

OBJECTIVE: Compare QuickVue Influenza A+B test with real-time RT-PCR for the diagnosis of influenza AH1N1 2009. MATERIAL AND METHODS: Retrospective-comparative study of 135 respiratory specimens from individuals with symptoms of influenza processed from May 2009 to October 2010.The above mentioned tests were performed simultaneously. For statistic analysisthe softwareof Confidence IntervalAnalysis 2000 was used. RESULTS: The parameters obtained were: sensitivity 62.96; specificity 94.44; negative predictive value 62.9; positive predictive value 94.44; positive likelihood ratio 11.33; negative likelihood ratio 0.39. Confidence intervals to 95,were calculated to all of the above data. DISCUSSION: The test QuickVue InfluenzaA+B is a rapid,simple test,with lower cost than real-time RT-PCR useful for identifying the type of virus outbreaks of influenza in a given population.It correlates well with more specific test and similar reports.

Estudio comparativo entre una prueba rápida y RT-PCR tiempo real en el diagnóstico de influenza AH1N1 2009 / Comparative study of a rapid testing with real time RT-PCR for diagnosis of influenza AH1N1 2009

OBJETIVO: Comparar la prueba QuickVue Influenza A+B empleando como estándar la RT-PCR tiempo real para influenza AH1N1 2009. MATERIAL Y MÉTODOS: Estudio retrospectivo-comparativo de 135 muestras de vías respiratorias de individuos sintomáticos para influenza procesadas de mayo 2009 a octubre 2010.Las pruebas citadas se realizaron simultáneamente. Se utilizó el software Confidence Interval Analysis 2000. RESULTADOS: Sensibilidad 62.96; especificidad 94.44; valor predictivo negativo 62.9; valor predictivo positivo 94.44; razón de probabilidad positiva 11.33 y razón de probabilidad negativa 0.39. Se calcularon intervalos de confianza a 95. DISCUSIÓN: Los valores obtenidos concuerdan con otros estudios donde la sensibilidad fluctúa de 50 a 70 y especificidad entre 90 y 95 por ciento. La prueba QuickVue Influenza A+B es rápida, simple y de menor costo que el RT-PCR tiempo real, útil para identificar el tipo de virus en brotes de influenza de una población determinada.

OBJECTIVE: Compare QuickVue Influenza A+B test with real-time RT-PCR for the diagnosis of influenza AH1N1 2009. MATERIAL AND METHODS: Retrospective-comparative study of 135 respiratory specimens from individuals with symptoms of influenza processed from May 2009 to October 2010.The above mentioned tests were performed simultaneously. For statistic analysisthe softwareof Confidence IntervalAnalysis 2000 was used. RESULTS: The parameters obtained were: sensitivity 62.96; specificity 94.44; negative predictive value 62.9; positive predictive value 94.44; positive likelihood ratio 11.33; negative likelihood ratio 0.39. Confidence intervals to 95,were calculated to all of the above data. DISCUSSION: The test QuickVue InfluenzaA+B is a rapid,simple test,with lower cost than real-time RT-PCR useful for identifying the type of virus outbreaks of influenza in a given population.It correlates well with more specific test and similar reports.