Infecção respiratória aguda por adenovirus: comparação dos métodos de PCR e imunofluorescência indireta para o seu diagnóstico e dados clínicos dos pacientes infectados

Infecções respiratórias por Adenovírus (ADV) são geralmente descritas associadas com alta mortalidade. O diagnóstico laboratorial é essencial para o estabelecimento da terapêutica adequada e para orientar a implantação de medidas preventivas evitando a propagação da infecção. Com o objetivo de analisar a sensibilidade e a especificidade dos métodos de avaliação de diagnóstico laboratorial, foi comparada a detecção de antígeno por imunofluorescência indireta (IF) com a reação em cadeia da polimerase específica (PCR) para detectar AdV em amostras respiratórias coletadas de pacientes internados com doença respiratória aguda. As amostras com resultados positivos foram inoculadas em cultura celular. Foram analisadas 381 amostras da secreção nasofaríngea coletadas durante o ano de 2008, das quais 2,6% foram positivas pela IF e 10% pela PCR, isolamento positivo foi obtido em 40% e 26% dos casos positivos pelos testes anteriores, respectivamente. A maioria dos pacientes infectados eram crianças com menos de seis meses de idade, e apesar do fato de que um número significativo de pacientes necessitou de cuidados intensivos, a taxa de mortalidade foi baixa (5%). Em conclusão, os métodos moleculares são úteis para o diagnóstico rápido de infecções por adenovírus com maior sensibilidade do que a detecção do antígeno, a sua introdução na rotina permitiu um aumento significativo no diagnóstico de infecções por adenovírus.Adenovirus (AdV) respiratory infections are usually described as being associated with high mortality rates. Laboratory diagnosis is essential for the establishment of the appropriate therapy, and for guiding the implementation of preventive measures in order to prevent the spread of the infection. Aiming to analyze the sensitivity and specificity of the laboratorial diagnosis methods available, we compared antigen detection by indirect immunofluorescence assay (IF), and a specific nested polymerase chain reaction (PCR), to detect AdV in respiratory samples collected from patients admitted to hospital with acute respiratory disease. Positive samples were inoculated into a cell culture to confirm the results. We analyzed 381 samples from the nasopharyngeal aspirates collected during the year 2008; of these, 2.6% tested were positive for adenovirus through IF and 10% through PCR; positive isolation was obtained in 40% and 26% of these cases, respectively. Most infected patients were children under six months of age, and despite of the fact that a significant number of patients required intensive care, the mortality rate was low (5%). In conclusion, molecular methods were found to be useful for rapid diagnosis of adenovirus infections with higher sensitivity than antigen detection; their introduction permitted a significant increase in diagnoses of adenovirus infections

Red blood cells in cerebrospinal fluid as possible inhibitory factor for enterovirus RT-PCR

ABSTRACT The presence of hemoglobin in samples are considered an important inhibitory factor for polymerase chain reaction (PCR). The aim of this study was to examine the influence of red blood cells (RBC)s in cerebrospinal fluid (CSF) as an inhibitory factor to reverse transcription polymerase chain reaction (RT-PCR) for enteroviruses (EV). Forty-four CSF samples from patients showing characteristics of viral meningitis were assessed for EV by RT-PCR. Viral RNA extracted with guanidine isothyocianate buffer and virus detection was performed by in-house nested PCR. Positivity for EV RT-PCR was higher in CSF samples without RBCs than in samples with RBCs: 13(26%) and 36(9.2%), p = 0.001. In the group with positive EV RT-PCR, the mean + SD CSF RBC was 37 ± 183 cell/mm3; the group with negative results had 580 + 2,890 cell/mm3 (p = 0.007). The acceptable upper limit for CSF RBCs that could not influence RT-PCR was 108 cells/mm3. CSF samples with negative results for EV RT-PCR have more erythrocytes

Impact and seasonality of human rhinovirus infection in hospitalized patients for two consecutive years

Objectives: To report epidemiological features, clinical characteristics, and outcomes of human rhinovirus (HRV) infections in comparison with other community acquired respiratory virus (CRV) infections in patients hospitalized for two consecutive years. Methods: This was a cross‐sectional study. Clinical, epidemiological, and laboratory data of patients hospitalized with acute respiratory syndrome in a tertiary care hospital from 2012 to 2013 were reviewed. Results: HRV was the most common CRV observed (36%, 162/444) and was present in the majority of viral co‐detections (69%, 88/128), mainly in association with human enterovirus (45%). Most HRV‐infected patients were younger than 2 years (57%). Overall, patients infected with HRV had a lower frequency of severe acute respiratory infection than those infected with other CRVs (60% and 84%, respectively, p = 0.006), but had more comorbidities (40% and 27%, respectively; p = 0.043). However, in the adjusted analysis this association was not significant. The mortality rate within the HRV group was 3%. Detection of HRV was more prevalent during autumn and winter, with a moderately negative correlation between viral infection frequency and temperature (r = −0.636, p < 0.001) but no correlation with rainfall (r = −0.036, p = 0.866). Conclusion: HRV is usually detected in hospitalized children with respiratory infections and is often present in viral co‐detections. Comorbidities are closely associated with HRV infections. These infections show seasonal variation, with predominance during colder seasons

Rotavirus infection in a tertiary hospital: laboratory diagnosis and impact of immunization on pediatric hospitalization

BACKGROUND AND OBJECTIVES: Rotavirus (RV) is the main etiological agent of diarrhea in childhood; its laboratory diagnosis is crucial to guide the clinical management and prevention of its spread. RV immunization was introduced in Brazilian 6-month-old children in 2006. The present study was aimed to evaluate three methodologies used for human RV detection in stool samples obtained from patients hospitalized due to gastroenteritis in a teaching hospital and report the impact of RV immunization in hospitalization by diarrhea. METHODS: 293 stool samples collected in the 2001-2008 period were analyzed by enzyme immunoassay (EIA), latex agglutination (LA) and polyacrylamide gel electrophoresis (PAGE). RESULTS: Rotavirus was detected in 34.8% of samples by LA assay, 28.3% of samples by EIA assay and in 25.6% of samples by PAGE assay. Considering the PAGE method as gold standard, the sensitivity, specificity and accuracy of EIA were 94.6%, 94.4% and 94.5%, and to LA were 82.6%, 81.6% and 81.9%, respectively. CONCLUSION: These results indicate that antigen detection by EIA is a rapid, sensitive and specific method, and could be used in large-scale applications for screening stool samples suspected of RV infection. This study showed decreased incidence of RV infection in hospitalized children prior to the implementation of the national immunization program against RV

Impact and seasonality of human rhinovirus infection in hospitalized patients for two consecutive years

Abstract Objectives: To report epidemiological features, clinical characteristics, and outcomes of human rhinovirus (HRV) infections in comparison with other community acquired respiratory virus (CRV) infections in patients hospitalized for two consecutive years. Methods: This was a cross-sectional study. Clinical, epidemiological, and laboratory data of patients hospitalized with acute respiratory syndrome in a tertiary care hospital from 2012 to 2013 were reviewed. Results: HRV was the most common CRV observed (36%, 162/444) and was present in the majority of viral co-detections (69%, 88/128), mainly in association with human enterovirus (45%). Most HRV-infected patients were younger than 2 years (57%). Overall, patients infected with HRV had a lower frequency of severe acute respiratory infection than those infected with other CRVs (60% and 84%, respectively, p = 0.006), but had more comorbidities (40% and 27%, respectively; p = 0.043). However, in the adjusted analysis this association was not significant. The mortality rate within the HRV group was 3%. Detection of HRV was more prevalent during autumn and winter, with a moderately negative correlation between viral infection frequency and temperature (r = −0.636, p < 0.001) but no correlation with rainfall (r = −0.036, p = 0.866). Conclusion: HRV is usually detected in hospitalized children with respiratory infections and is often present in viral co-detections. Comorbidities are closely associated with HRV infections. These infections show seasonal variation, with predominance during colder seasons

Acute gastroenteritis and enteric viruses in hospitalised children in southern Brazil: aetiology, seasonality and clinical outcomes

Viral acute gastroenteritis (AG) is a significant cause of hospitalisation in children younger than five years. Group A rotavirus (RVA) is responsible for 30% of these cases. Following the introduction of RVA immunisation in Brazil in 2006, a decreased circulation of this virus has been observed. However, AG remains an important cause of hospitalisation of paediatric patients and only limited data are available regarding the role of other enteric viruses in these cases. We conducted a prospective study of paediatric patients hospitalised for AG. Stool samples were collected to investigate human adenovirus (HAdV), RVA, norovirus (NoV) and astrovirus (AstV). NoV typing was performed by nucleotide sequencing and phylogenetic analysis. From the 225 samples tested, 60 (26%) were positive for at least one viral agent. HAdV, NoV, RVA and AstV were detected in 16%, 8%, 6% and 0% of the samples, respectively. Mixed infections were found in nine patients: HAdV/RVA (5), HAdV/NoV (3) and HAdV/NoV/RVA (1). The frequency of fever and lymphocytosis was significantly higher in virus-infected patients. Phylogenetic analysis of NoV indicated that all of these viruses belonged to genotype GII.4. The significant frequency of these pathogens in patients with AG highlights the need to routinely implement laboratory investigations