Métodos diagnósticos para la infección por SARS-CoV-2 / Diagnostic methods for SARS-CoV-2 infection

En diciembre de 2019 se identificó el virus SARS-CoV-2, cuya rápida propagación global puso en estado de emergencia al mundo entero, llevando al ser humano a una situación sin antecedente cercano. El objetivo de esta revisión es describir los métodos diagnósticos utilizados actualmente para identificar la infección por SARS-CoV-2. Las manifestaciones clínicas y el espectro imagenológico de la enfermedad son muy inespecíficos y no permiten realizar un diagnóstico certero. Por esta razón, es esencial una apropiada toma de muestra respiratoria en el momento y sitio anatómico adecuado para un diagnóstico preciso de COVID-19. La técnica de muestreo más utilizada es el hisopado nasofaríngeo y la prueba diagnóstica más fiable se basa en la retrotranscripción seguida por reacción en cadena de la polimerasa en tiempo real (RT-PCR). No obstante, existen otras técnicas moleculares, como también tests serológicos para detectar anticuerpos o fragmentos antigénicos del SARS-CoV-2. Más allá de la precisión diagnóstica, es importante tener en cuenta la probabilidad basal (pretest) para interpretar correctamente el resultado obtenido y aislar aquellos posibles falsos negativos. Con el objetivo de evitar la saturación del sistema de salud es imprescindible contar con información y métodos diagnósticos precisos para detectar tempranamente los focos de infección y reducir la transmisión comunitaria, utilizando eficazmente los diferentes recursos diagnósticos. (AU)

In December 2019, the SARS-CoV-2 virus was identified for the first time, whose rapid global spread put the entire world in a state of emergency, leading humans to an unprecedented situation with no immediate history. The main purpose of this review is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. The clinical manifestations and the imaging spectrum of the disease are nonspecific and do not allow an accurate diagnosis to be made. For this reason, an appropriate respiratory sampling at the right time and anatomical site is essential for an accurate diagnosis of COVID-19. The most widely used sampling technique is nasopharyngeal swab, and the most reliable diagnostic test is by reverse transcription followed by real-time polymerase chain reaction (RT-PCR). However, there are other molecular techniques, as well as serological tests to detect antibodies or antigenic fragments of SARS-CoV-2. Beyond the diagnostic precision, it is important to take into account the baseline probability (pre-test) to correctly interpret the result obtained and isolate those possible false negatives. In order to avoid saturation of the health system, it is essential to have accurate information and diagnostic methods to detect outbreaks of infection in early stages and to reduce communitary transmission, making effective use of the various diagnostic resources. Coronavirus infections/diagnosis, viral/diagnosis, pandemics, clinical laboratory techniques, real-time polymerase chain reaction, antigens, viral/analysis. (AU)

The effects of different restorative materials on periodontopathogens in combined restorative-periodontal treatment

Abstract Objective The aim of the study was to evaluate the association between subgingival restorations and the target periodontopathogenic bacteria (Pg, Td and Pi) in subgingival biofilm during one year after combined restorative-periodontal treatment. Material and Methods Seventeen systemically healthy subjects, who were positive for the presence of three cervical lesions associated with gingival recessions in three different adjacent teeth, were included in the study. A total of 51 combined defects were treated with connective tissue graft plus a nanofilled composite resin (NCR+CTG), a resin-modified glass ionemer cement (RMGI+CTG) and a fluoride-releasing resin material with pre-reacted glass (PRG), called giomer (Giomer+CTG). Periodontal clinical measurements and subgingival plaque samples were obtained from all combined defects at baseline and at 6 and 12 months after the surgery. The number of bacteria were evaluated by the real-time polymerase chain reaction (qPCR) method. Results No statistically significant difference in the amount of DNA copies of Pg, Td and Pi was observed in any of the groups at any time points (p>0.05). In addition, there was no statistically significant difference in the amount of DNA copies of the bacteria at baseline and at 6 and 12 months postoperatively, regardless of treatment group (p>0.05). Conclusion This study suggests that subgingivally placed NCR, RMGI and giomer restorations can show similar effects on periodontopathogenic bacteria in the treatment of gingival recessions that are associated with noncarious cervical lesions (NCCLs).

Doença peri-implantar follow-up microbiológico de 5 anos e revisão sistemática com meta-análise / Peri-implant disease: Microbiological 5-year follow-up and systematic review with meta-analysis

Objetivos: Avaliar, em um estudo longitudinal de 5 anos, a associação entre o diagnóstico da doença peri-implantar (DPi) e a contagem de patógenos na presença e ausência de terapia de manutenção periodontal/peri-implantar (TMPP). Realizar uma revisão sistemática de estudos observacionais para avaliar se dados presentes na literatura indicam uma maior prevalência de peri-implantite (PI) em indivíduos com diagnóstico ou histórico de periodontite (PE). Métodos: O estudo longitudinal microbiológico foi realizado avaliando-se, através da técnica da reação em cadeia da polimerase em tempo real, as seguintes espécies bacterianas: T. forsythia, T. denticola, P. gingivalis, P. intermedia, F. nucleatum e A. naeslundii em 80 indivíduos com mucosite peri-implantar (MP) que realizavam consultas para manutenção periodontal/peri-implantar regular (GTP, n = 39) comparados aos que não realizavam (GNTP, n = 41). Para a revisão sistemática uma busca eletrônica foi conduzida até março de 2016. Foram encontrados 1330 estudos, 17 artigos foram incluídos na análise final (PROSPERO CRD42015009518). A meta-análise foi realizada para presença ou ausência de PI. Medidas de efeito sumário e taxas de razão de chances (OR) com 95% IC foram calculadas. Resultados: Os resultados do estudo longitudinal mostraram que, após 5 anos, houve uma diminuição da carga bacteriana total (CBT), na frequência das bactérias analisadas do complexo laranja (p = 0.013) e nas frequências isoladas de T. forsythia (p = 0.000), P. gingivalis (p = 0.003) e P. intermedia (p = 0.013) no GTP. Indivíduos com PI apresentaram maiores frequências de P. gingivalis (GNTP: p = 0,030; GTP: p = 0,000), T. denticola (GNTP: p = 0,017) e F. nucleatum (GTP e GNTP; p = 0.002) comparados aos com MP. Indivíduos que desenvolveram PI apresentaram um aumento na CBT (GTP: p = 0.047; GNTP: p = 0,055) e na frequência isolada de P. gingivalis (GNTP: p = 0,002) e F. nucleatum (GTP e GNTP; p = 0.000). Não houve diferenças estatisticamente significativas intergrupos em relação aos patógenos do complexo vermelho (p > 0,05). Tanto nos indivíduos com MP (T1 e T2: p = 0,000), quanto nos indivíduos com PI (T2: p = 0,000), a frequência do complexo laranja foi significativamente menor no GTP. A meta-análise dos estudos coorte mostrou que indivíduos (OR = 7.22), e implantes (OR = 5.63) apresentaram maior risco de desenvolver PI. Nos estudos transversais, em análises não ajustadas, indivíduos com PE apresentaram maior chance de ter PI (OR = 3.18). Quando a análise foi ajustada para tabagismo e diabetes não houve aumento estatisticamente significativo no risco para PI (OR = 1.73; IC 95% 0.86- 3.45). Conclusões: Pôde-se concluir que a ausência de consultas regulares para manutenção periodontal/peri-implantar foi associada com pior condição clínica periimplantar, maior incidência de PI e um aumento significativo na CBT. Adicionalmente, indivíduos com diagnóstico de PI apresentaram maiores frequências de P. gingivalis, T. denticola e F. nucleatum e maior CBT. A revisão sistemática permitiu concluir que indivíduos com diagnóstico ou histórico de PE podem apresentar um risco aumentado para PI. Mais estudos prospectivos são necessários para confirmar a evidência, principalmente os ensaios clínicos controlados randomizados

Aims: Evaluate, in a 5-year longitudinal study, the association between peri-implant disease's (DPi) diagnosis and the count of pathogens in the presence and absence of periodontal/peri-implant maintenance therapy. Conduct a systematic review of observational studies to evaluate whether data in the literature indicates a higher prevalence of peri-implantitis (PI) in subjects with diagnosis or history of periodontitis (PE). Methods: the microbiologic study was performed evaluating, through polymerase chain reaction in real time technique, the following bacterial species: T. forsythia, T. denticola, P. gingivalis, P. intermedia, F. nucleatum and A. naeslundii in 80 patients with peri-implant mucositis (PM) that were queries for periodontal/periimplant regular maintenance (GTP, n = 39) compared to those who were not (GNTP, n = 41). For the systematic review an electronic search was conducted until March 2016. It was found 1330 studies, 19 articles were included in the final analysis (PROSPERO CRD42015009518). The meta-analysis was performed for presence or absence of PI. Summary measures and odds ratio (OR) with 95% IC were calculated. Results: the results of the longitudinal study showed that, after 5 years, there was a decrease in the total bacterial load (TBL), the frequency of bacteria analyzed in the orange complex (p = 0.013) and in the frequencies of T. forsythia (p = 0.000), P. gingivalis (p = 0.003) and P. intermedia (p = 0.013) in the GTP. Individuals with PI had higher frequencies of P. gingivalis (GNTP: p = 0.030; GTP: p = 0.000), T. denticola (GNTP: p = 0.017) and T. nucleatum (GTP and GNTP; p = 0.002) compared to those with PM diagnosis. Individuals who have developed PI showed an increase in TBL (GTP: p = 0047; GNTP: p = 0.055) and in the isolated frequencies of P. gingivalis (GNTP: p = 0.002) and F. nucleatum (GTP and GNTP; p = 0.000). There were no statistically significant differences intergroups in relation to red complex pathogens (p > 0.05). Both in individuals with PM (T1 and T2: p = 0.000), as in individuals with PI (T2: p = 0.000), the frequency of orange complex was significantly lower in the GTP. The meta-analysis of cohort studies showed that individuals (OR = 7.22), and implants (OR = 5.63) presented a higher risk of developing PI. In the cross-sectional studies, in unadjusted analyses, individuals with PE presented a higher chance of having PI (OR = 3.18). When the analysis was adjusted for smoking and diabetes, there was no statistically significant increase in risk for PI (OR = 1.73; 95% CI 0.86-3.45). Conclusions: it might be concluded that the absence of regular periodontal/peri-implant maintenance was associated with worse peri-implant clinical condition, higher incidence of PI and a significant increase in TBL. Additionally, individuals diagnosed with PI showed greater frequencies of P. gingivalis, T. denticola and F. nucleatum and largest TBL. The systematic review showed that individuals diagnosed or with PE's history may have an increased risk for PI. More prospective studies are needed to confirm this evidence, especially the randomized controlled clinical trials

CD8+T cell activation associated with viral replication in chronic infection

PD-1 expression is controlled during T-cell activation. PD-1 has an important role in regulating immune response as well as tolerance. During chronic hepatitis C virus [HCV] infection there is high level of PD-1 expression on exhausted CD8+T cells. There is also reduced expression of T-bet. T-bet is identified as a transcriptional repressor of Pdcd1. The study will attempt to find out the level of expression of PD-1 on peripheral CD8 + T-cells, associated with chronic HCV infection. Fifty patients with chronic hepatitis C virus infection [CHCV], whose age ranged between [16-59] years, were selected from the National Hepatology and Tropical Medicine Research Institute were included in this study, before Interferon and ribavirin therapy, and fifteen healthy individuals were included to serve as controls. All the patients and controls were subjected to the following: history, clinical examination, abdominal ultrasonography and collection of blood samples for routine laboratory investigations. CBCs and analysis of the expression of surface markers on CD8+T cells and PD-1. Our results suggested that increased expression of PD-1 cells was an additional inhibitory mechanism that contributed to virus-specific CD8 + T cell exhaustion in chronic hepatitis C virus [CHCV] infected patients. Our study concluded that there's significant increase in PD-1 expression of circulating HCV-specific CD8 + T cells in CHCV patients. The blockade of the inhibitory receptors [PD-1] programmed cell death is considered as a novel strategy for the treatment of chronic HCV infection

Performance of a rapid test versus real-time PCR for diagnosis of H1N1 swine flu

For effective control and treatment of swine influenza, rapid and cost-effective diagnosis is important. Although the gold-standard method for the diagnosis of influenza virus is culture isolation, it is not routinely used in outpatient settings because of the cost and the time needed to complete the assay. This has led to the development of an array of rapid influenza diagnostic tests. The aim of this study was to compare between the performance of CerTest Swine Flu card and RT-PCR in the detection of H1N1 infection. This study included 40 clinically suspected cases of H1N1. Nasal and throat swabs were collected from patients, placed in viral transport medium, and kept at 4[degree]C until being tested on the same day for the presence of H1N1, using the CerTest Swine Flu test and real-time PCR. Of these 40 suspected cases, seven [17.5%] were found to be positive by the PCR technique, whereas 33 [82.5%] were found to be negative. Of the seven positive cases by the PCR technique, six were found to be positive by the rapid test, and thus the sensitivity of the rapid test was found to be 85.7%, and the specificity was 100%.CerTest Swine Flu card rapid test was found to have reliable sensitivity and specificity compared with the gold-standard RT-PCR

Detection of mycobacterial DNA directly from FNAC samples of tuberculous lymphadenopathy using real-time PCR: A preliminary study.

Background: Fine needle aspiration cytology (FNAC) is most commonly used in first line investigation for tuberculous lymphadenopathy (TBLAP). Real-time polymerase chain reaction (PCR) an extremely versatile technique is being used for diagnosis and follow up of patients with infectious diseases. It can also be used for detecting Mycobacterium tuberculosis (Mtb) DNA in FNAC samples of TBLAP for rapid diagnosis and treatment. Aim: Detection of Mtb DNA on FNAC samples of tuberculous lymphadenopathy using Real-time PCR. Material and Methods: Twelve clinico-cytologically diagnosed TBLAP cases and five controls were included in the study. FNA samples were used for studying morphology, AFB demonstration, culture and for detecting Mtb DNA using Real-time PCR. Results: Mtb DNA was detected in ten cases (83.33 %) by Real-time PCR. ZN stain was positive in eight cases and culture in six cases. Conclusion: Detection of Mtb DNA in FNAC samples using Real-time PCR is a time saving, logical, economical approach over the culture based method.