Saliva screening of health care workers for SARS-CoV-2 detection / Análisis del personal de salud a partir de saliva para detección de SARS-CoV-2

Abstract Health care workers (HCWs) are at high risk for SARS-CoV-2. In addition, pre-symptomatic or asymptomatic transmission accounts for around half of the cases. Saliva testingis an option to detect SARS-CoV-2 infection. To determine the performance of saliva samplesfor screening, HCWs were tested for SARS-CoV-2 by RT-PCR. Those with a positive result insaliva were tested by nasopharyngeal swabbing for viral RNA detection and blood collectionto search for the presence of specific antibodies. In September---October 2020, 100 HCWs wereenrolled and followed up. Six subjects (6%) tested positive in saliva. Of them, 5/6 were positivein a subsequent nasopharyngeal swab and 4/6 developed signs and symptoms compatible withCOVID-19. Among the latter, 3 seroconverted while asymptomatic HCWs remained seronega-tive. Saliva screening was helpful for identifying SARS-CoV-2 infection in HCWs. This screeningpermitted rapid personnel isolation avoiding further transmission of the virus in the hospitalsetting.

Resumen El personal de salud (PS) tiene un alto riesgo de contraer SARS-CoV-2. La transmisión presintomática/asintomática representa alrededor de la mitad de los casos y el análisis a partir de muestras de saliva puede ser una opción para detectar la infección. Para determinar el rendimiento de estas muestras, 100 voluntarios del PS se sometieron a la detección de SARS-CoV-2 por RT-PCR en muestras de saliva en el período septiembre-octubre de 2020. De aquellos con resultado positivo en saliva, se tomaron hisopados nasofaríngeos para detectar ARN viral y muestras de suero para evaluar anticuerpos específicos. Se detectó ARN viral en la saliva de seis individuos (6%). De ellos, 5/6 fueron SARS-CoV-2 positivos en hisopado nasofaríngeo y 4/6 desarrollaron signos y síntomas compatibles con COVID-19. Entre estos últimos, tres serocon-virtieron, en tanto que los voluntarios asintomáticos permanecieron seronegativos. La muestra de saliva fue útil para identificar la infección por SARS-CoV-2 en esta cohorte del personal de salud y así proceder al rápido aislamiento de los individuos infectados, lo que evitó una mayor transmisión del virus en el ámbito hospitalario.

Saliva screening of health care workers for SARS-CoV-2 detection.

Health care workers (HCWs) are at high risk for SARS-CoV-2. In addition, pre-symptomatic or asymptomatic transmission accounts for around half of the cases. Saliva testing is an option to detect SARS-CoV-2 infection. To determine the performance of saliva samples for screening, HCWs were tested for SARS-CoV-2 by RT-PCR. Those with a positive result in saliva were tested by nasopharyngeal swabbing for viral RNA detection and blood collection to search for the presence of specific antibodies. In September-October 2020, 100 HCWs were enrolled and followed up. Six subjects (6%) tested positive in saliva. Of them, 5/6 were positive in a subsequent nasopharyngeal swab and 4/6 developed signs and symptoms compatible with COVID-19. Among the latter, 3 seroconverted while asymptomatic HCWs remained seronegative. Saliva screening was helpful for identifying SARS-CoV-2 infection in HCWs. This screening permitted rapid personnel isolation avoiding further transmission of the virus in the hospital setting.

Genotypes and phylogenetic analysis of adenovirus in children with respiratory infection in Buenos Aires, Argentina (2000-2018).

Human adenoviruses (HAdV) are one of the most frequent causes of respiratory infections around the world, causing mild to severe disease. In Argentina, many studies focused on the association of HAdV respiratory infection with severe disease and fatal outcomes leading to the discovery in 1984 of a genomic variant 7h associated with high fatality. Although several molecular studies reported the presence of at least 4 HAdV species (B, C, D and E) in Argentina, few sequences were available in the databases. In this study, sequences from the hexon gene region were obtained from 141 patients as a first approach to assess the genetic diversity of HAdVs circulating in Buenos Aires, Argentina. Phylogenetic analysis of these sequences and others recovered from public databases confirmed the circulation of the four above-mentioned species represented by 11 genotypes, with predominance in species B and C and shifts in their proportion in the studied period (2000 to 2018). The variants detected in Argentina, for most of the genotypes, were similar to those already described in other countries. However, uncommon lineages belonging to genotypes C2, C5 and E4 were detected, which might indicate the circulation of local variants and will deserve further studies of whole-genome sequences.

Self-collected saliva for SARS-CoV-2 detection: A prospective study in the emergency room.

Current diagnostic standards involve severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection in nasopharyngeal swabs (NPS), but saliva is an attractive and noninvasive option for diagnosis. The objectives were to determine the performance of saliva in comparison with NPS for detecting SARS-CoV-2 and to compare the optimized home brew reverse-transcription polymerase chain reaction (RT-PCR) with a commercial RT-PCR. Paired NPS and saliva specimens were prospectively collected and tested by RT-PCR from patients presenting at an emergency room with signs and symptoms compatible with coronavirus disease-2019. A total of 348 samples from 174 patients were tested by RT-PCR assays. Among 174 patients with symptoms, 63 (36%) were SARS-CoV-2 positive in NPS using the optimized home-brew PCR. Of these 63 patients, 61 (98%) were also positive in saliva. An additional positive SARS-CoV-2 saliva was detected in a patient with pneumonia. Kappa Cohen's coefficient agreement between NPS and saliva was 0.96 (95% confidence interval [CI], 0.90-0.99). Median Ct values in NPS versus saliva were 18.88 (interquartile range [IQR], 15.60-23.58; range, 11.97-38.10) versus 26.10 (IQR, 22.75-30.06; range, 13.78-39.22), respectively (p < .0001). The optimized home-brew RT-PCR demonstrated higher analytical and clinical sensitivity compared with the commercial RT-PCR assay. A high sensitivity (98%) and agreement (kappa 0.96) in saliva samples compared to NPS was demonstrated when using an optimized home-brew PCR even when the viral load in saliva was lower than in NPS. This noninvasive sample is easy to collect, requires less consumable and avoids discomfort to patients. Importantly, self-collection of saliva can diminish exposure to healthcare personnel.

Direct costs and clinical impact of adenovirus genotype 8 conjunctivitis outbreak in a neonatology unit.

OBJECTIVE: To report a conjunctivitis outbreak in a neonatology intensive care unit (NICU) and determine the associated economic impact. DESIGN: Prospective observational study. SETTING: Centro de Educación Médica e Investigaciones Clínicas (CEMIC) University Hospital, a private, tertiary-care healthcare institution in Buenos Aires, Argentina. PARTICIPANTS: The study included 52 NICU neonates and 59 NICU-related healthcare workers (HCWs) from CEMIC hospital. METHODS: Neonates and HCWs were swabbed for real-time polymerase chain reaction (PCR) testing, viral culture, and typing by sequencing. Infection control measures, structural and logistic changes were implemented. Billing records were analyzed to determine costs. RESULTS: From January 30 to April 28, 2018, 52 neonates were hospitalized in the NICU. Among them, 14 of 52 (21%) had bilateral conjunctivitis with pseudomembranes. Symptomatic neonates and HCWs were HAdV-D8 positive. Ophthalmological symptoms had a median duration of 18 days (IQR, 13-24.5). PCR positivity and infectious range had a median duration of 18.5 days. As part of containment measures, the NICU and the high-risk pregnancy unit were closed to new patients. The NICU was divided into 2 areas for symptomatic and asymptomatic patients; a new room was assigned for the general nursery, and all deliveries from the high-risk pregnancy unit were redirected to other hospitals. The outbreak cost the hospital US$205,000: implementation of a new nursery room and extra salaries cost US$30,350 and estimated productivity loss during 1 month cost US$175,000. CONCLUSIONS: Laboratory diagnosis confirmed the cause of this outbreak as HAdV-D8. The immediate adoption and reinforcement of rigorous infection control measures limited the nosocomial viral spread. This outbreak represented a serious institutional problem, causing morbidity, significant economic loss, and absenteeism.

Respiratory pathogens in infants less than two months old hospitalized with acute respiratory infection.

Lower acute respiratory infections (ARI) are a frequent cause of morbidity and mortality in infants, respiratory viruses being the major causative agents. The aim of this work was to determine the respiratory pathogen frequency, the clinical characteristics and the outcome in infants <2 months old hospitalized with ARI. A retrospective study was performed during a five-year period (2008-2011, 2014-2016). Respiratory viruses and atypical bacteria were studied using the FilmArray-Respiratory Panel. Demographic and clinical characteristics, hospitalization course and outcomes were evaluated. Of the 137 infants <2 months old hospitalized with ARI studied, a 94.9% positivity rate as determined in 117 infants with community-acquired infection and 20.0% in 20 infants who acquired the infection during their birth hospitalization in the neonatal intensive care units (NICU) (nosocomial ARI) (p<0.001). In infants with community-acquired infection, Respiratory syncytial virus (RSV) (52.1%) and Rhinovirus/Enterovirus (RV/EV) (41.0%) were the most frequent detected pathogens. Coinfections were determined in one quarter of the infants, RSV-RV/EV being the most frequent combination. In infants with nosocomial infection, RV/EV, RSV or Parainfluenza-3 were detected as single pathogens. Most infants with community-acquired infection presented lower ARI (81.2%) while most infants in the NICU had upper ARI (55.0%). The median length of stay (LOS) in infants with community-acquired ARI was 4 days (IQR: 2-6). Positive infants with nosocomial infection had longer median LOS (71 days [IQR:42-99]) compared to negative infants (58 days [IQR: 49-71]) (p=0.507). Respiratory viruses were detected as the major causative agents of community-acquired infection in hospitalized infants <2-months old, RSV and RV/EV being the most frequently detected. Although a low pathogen positivity rate was observed in infants with nosocomial infection, they may prolong the LOS.

Nosocomial Transmission and Genetic Diversity of Rhinovirus in a Neonatal Intensive Care Unit.

Rhinoviruses were detected as sole pathogens in 6 preterm infants who developed severe respiratory infections while hospitalized in a neonatal intensive care unit. We confirmed 2 nosocomial rhinovirus transmission episodes and describe the genetic diversity of rhinovirus strains that circulated simultaneously during a winter season.

Incidence of viral respiratory infections in a prospective cohort of outpatient and hospitalized children aged ≤5 years and its associated cost in Buenos Aires, Argentina.

BACKGROUND: Although information about the incidence of viral respiratory illnesses and their associated cost can help health officials explore the value of interventions, data are limited from middle-income countries. METHODS: During 2008-2010, we conducted a prospective cohort study and followed ~1,800 Argentinian children aged ≤5 years to identify those children who were hospitalized or who sought care at an emergency room with any acute respiratory infection sign or symptom (e.g., rhinorrhea, cough, wheezing, tachypnea, retractions, or cyanosis). Respiratory samples were obtained for respiratory syncytial virus, influenza, parainfluenza, adenovirus, and metapneumovirus testing by immunofluorescence and for rhinovirus by real-time reverse transcription polymerase chain reaction. RESULTS: The incidence of respiratory syncytial virus (24/1000 children-years), human metapneumovirus (8/1000 children-years), and influenza (8/1000 children-years) illnesses was highest among hospitalized children aged <6 months and decreased among older children. In contrast, the incidence of rhinovirus was highest (12/1000 children-years) among those aged 6-23 months. In the emergency room, the incidence of rhinovirus was 459; respiratory syncytial virus 352; influenza 185; parainfluenza 177; metapneumovirus 130; and adenovirus 73/1,000 children-years. The total cost of hospitalization was a median of US$529 (Interquartile range, US$362-789). CONCLUSIONS: Our findings indicate that respiratory viruses, in particular rhinovirus, respiratory syncytial virus, metapneumovirus, and influenza may be associated with severe illness causing substantial economic burden.

[Respiratory viral diagnosis by using an automated system of multiplex PCR (FilmArray) compared to conventional methods]. / Diagnóstico de virus respiratorios utilizando un sistema automatizado de PCR múltiples (FilmArray) y su comparación con métodos convencionales.

Acute respiratory infections, which are commonly caused by viruses, are an important cause of morbidity and mortality in children. In Argentina, national surveillance programs for the detection of respiratory viruses are usually performed by using immunofluorescence (IF) assays, although it is well known that molecular methods are more sensitive. An automated multiplex PCR device, the FilmArray-Respiratory Panel (FilmArray-RP), can detect 17 viral and 3 bacterial pathogens in a closed system that requires only 5 min of hands-on time and 1h of instrumentation time. A total of 315 respiratory samples from children under 6 years of age suffering from acute respiratory infections, were studied by IF for 8 respiratory viruses and by RT-PCR for rhinoviruses. Later, these samples were tested by the FilmArray-RP. The positivity frequency obtained for the 9 viruses tested was 75% by IF/RT-PCR and 92% by the FilmArray-RP. The positive and negative percent agreement between both methods was 70.5% whereas the negative percent agreement was 99.6% (95% confidence interval:65.5-75.1 and 99.2-99.8 respectively). The FilmArray-RP allowed a higher positive diagnosis (97%) and detected other viruses such as coronavirus NL63, 229E, OC43, HKU1 (10%) and bocavirus (18%). In addition, this method identified multiple coinfections (39%) with 2, 3, 4 and up to 5 different viruses. At present, IF is still the most frequently used method in most Latin American countries for respiratory viruses diagnosis due to its low cost, its capability to process a high number of samples simultaneously and the fast determination of results for the most frequent viruses, which are available within 5h. However, the coming incorporation of molecular methods in routine procedures will significantly increase the diagnostic yield of these infections.

Diagnóstico de virus respiratorios utilizando un sistema automatizado de PCR múltiples (FilmArray) y su comparación con métodos convencionales / Respiratory viral diagnosis by using an automated system of multiplex PCR (FilmArray) compared to conventional methods

Las infecciones respiratorias agudas producen una importante morbimortalidad y comúnmente son causadas por virus. En Argentina, los programas de vigilancia epidemiológica se basan en la detección de antígenos virales por inmunofluorescencia (IF), aunque es bien conocido que los métodos moleculares son más sensibles. El panel respiratorio (PR) FilmArray (PR-FilmArray) es un equipo comercial automatizado de PCR múltiples que detecta 17 virus respiratorios y 3 bacterias, en un sistema cerrado que requiere 5 min de procesamiento y una 1 h de instrumentación. Se evaluó un total de 315 muestras respiratorias de niños menores de 6 años con infecciones respiratorias agudas por IF para 8 virus respiratorios y por RT-PCR para rinovirus. Posteriormente, estas muestras se estudiaron con el PR-FilmArray. La frecuencia de positividad al considerar los 9 virus estudiados por IF y RT-PCR fue del 75 %; por PR-FilmArray fue del 92 %. El porcentaje de acuerdo positivo entre ambas metodologías fue del 70,5 % y el de acuerdo negativo fue del 99,6 % (intervalo de confianza 95 %: 65,5-75,1 y 99,2-99,8, respectivamente). El PR-FilmArray permitió obtener un mayor diagnóstico positivo (97 %) y detectó otros virus, como los coronavirus NL63, 229E, OC43 y HKU1 (10 %) y los bocavirus (18 %). Además, permitió identificar coinfecciones múltiples (39 %) con 2, 3, 4 y hasta 5 virus. Actualmente, la IF continúa siendo el método más utilizado en los países latinoamericanos para el diagnóstico de virus respiratorios por su bajo costo, por su capacidad para procesar un alto número de muestras simultáneamente y porque los resultados de los virus más frecuentes están disponibles en 5 h. Sin embargo, la futura incorporación de métodos moleculares aumentaría notablemente la capacidad diagnóstica.

Acute respiratory infections, which are commonly caused by viruses, are an important cause of morbidity and mortality in children. In Argentina, national surveillance programs for the detection of respiratory viruses are usually performed by using immunofluorescence (IF) assays, although it is well known that molecular methods are more sensitive. An automated multiplex PCR device, the FilmArray-Respiratory Panel (FilmArray-RP), can detect 17 viral and 3 bacterial pathogens in a closed system that requires only 5 min of hands-on time and 1 h of instrumentation time. A total of 315 respiratory samples from children under 6 years of age suffering from acute respiratory infections, were studied by IF for 8 respiratory viruses and by RT-PCR for rhinoviruses. Later, these samples were tested by the FilmArray-RP. The positivity frequency obtained for the 9 viruses tested was 75 % by IF/RT-PCR and 92 % by the FilmArray-RP. The positive and negative percent agreement between both methods was 70.5 % whereas the negative percent agreement was 99.6 % (95 % confidence interval:65.5-75.1 and 99.2-99.8 respectively). The FilmArray-RP allowed a higher positive diagnosis (97 %) and detected other viruses such as coronavirus NL63, 229E, OC43, HKU1 (10 %) and bocavirus (18 %). In addition, this method identified multiple coinfections (39 %) with 2, 3, 4 and up to 5 different viruses. At present, IF is still the most frequently used method in most Latin American countries for respiratory viruses diagnosis due to its low cost, its capability to process a high number of samples simultaneously and the fast determination of results for the most frequent viruses, which are available within 5 h. However, the coming incorporation of molecular methods in routine procedures will significantly increase the diagnostic yield of these infections.

Genetic diversity and clinical impact of human rhinoviruses in hospitalized and outpatient children with acute respiratory infection, Argentina.

BACKGROUND: Human rhinoviruses (HRV) are recognized as a cause of upper and lower acute respiratory infections (ARI). The circulating species and their clinical impact were not described in Argentina. OBJECTIVES: To describe the molecular epidemiology of HRV in children and to determine the association of HRV species with outcome and severity. STUDY DESIGN: Hospitalized and outpatients children <6 years old with ARI without comorbidities (n=620) were enrolled (2008-2010). Demographic, clinical data and outcome were analyzed. HRV were identified by RT-PCR. Phylogenetic analysis and demographic reconstruction for HRV were performed in selected samples. RESULTS: HRV were detected in 252/620 (40.6%) of children; 8.5% in viral coinfection. Bronchiolitis (55%) and pneumonia (13%) were the most frequent clinical diagnosis. Of 202 inpatients with HRV: 72% required oxygen supplementation, 11% intensive care unit and 3% mechanical ventilation. HRV were identified as a risk factor for hospitalization (OR: 2.47). All three HRV species were detected being HRV-A (55%) and HRV-C (43%) the most frequent; HRV-B was infrequent (2%). Of 44 sequenced HRV, 30 genotypes were detected. Seven of them were the most prevalent and circulated during limited periods of time. The demographic reconstruction revealed a constant population size and a high turnover rate of genotypes. Demographic and clinical outcome were similar for HRV-A and HRV-C infections. CONCLUSION: This study highlights the clinical impact of HRV in children without comorbidities as a cause of lower ARI and hospitalization. The high frequency of HRV infections may be associated with the simultaneous circulation of genotypes and their high turnover rate.

Molecular and serological characterization of species B2 adenovirus strains isolated from children hospitalized with acute respiratory disease in Buenos Aires, Argentina.

BACKGROUND: Between September 2000 and November 2005, approximately 10% of the retrospectively examined human adenovirus (HAdV)-positive pediatric cases of acute respiratory disease (ARD) requiring hospitalization at the Hospital Nacional de Pediatria Juan P. Garrahan in Buenos Aires, Argentina, were found to have a HAdV-B2 infection. OBJECTIVE: To characterize genetically and antigenically the HAdV-B2 virus isolates. STUDY DESIGN: Restriction enzyme analysis (REA), hexon and fiber gene sequencing and virus neutralization assays (VN) were carried out on 8 HAdV-B2 respiratory virus isolates. RESULTS: REA showed that the 8 examined HAdV-B2 virus isolates were HAdV11, belonging to two genomic variants: HAdV11a and a BclI variant of HAdV11c which we designated 11c4. Molecular analysis of the hexon genes showed that both REA variants had a HAdV11-like hexon gene. Confirming previous reports, the 7 HAdV11a virus isolates were found to have HAdV14-like fiber genes and therefore are HAdV H11/F14. The fiber gene of the HAdV11c4 virus isolates most closely resembled that of various strains of HAdV7. In VN assays, the 4 tested HAdV11a strains were serotyped as HAdV11-14. The HAdV11c4 strain was serotyped as HAdV11 but also showed a weak but significant reactivity with antiserum to HAdV7. Compared with the other HAdV-positive cases in our study, infection with HAdV11 caused a similarly severe disease. CONCLUSIONS: Our results provide evidence to the long term world-wide circulation of HAdV H11/F14 as a causative agent of ARD. Combined, our molecular and serology data support the rationale to base the molecular typing and designation of recombinant viruses on the sequences of the hexon and fiber genes.

Viral etiology of acute respiratory infections in hospitalized and outpatient children in Buenos Aires, Argentina.

OBJECTIVES: To determine and compare the viral frequency, seasonality and clinical-demographic features in 2 groups of children (hospitalized versus outpatients) with acute respiratory infections. MATERIAL AND METHODS: A cross-sectional, descriptive study was performed from 2008 to 2010 in 620 children <6 years of age with acute respiratory infection. Respiratory samples were studied for classical respiratory viruses by immunofluorescence and for human rhinoviruses (HRV) by real-time reverse transcription polymerase chain reaction. Clinical and demographic data were recorded. RESULTS: Viral detection by immunofluorescence was 48% in 434 inpatients and 37% in 186 outpatients. Viral diagnosis increased to 83% and 62%, respectively, when testing for HRV. HRV (41%) and respiratory syncytial virus (RSV) (27%) were most common viruses identified, followed by metapneumovirus (9%), influenza A and parainfluenza (3%), adenovirus and influenza B (2%). HRV frequency was significantly higher in hospitalized patients (47%) than in outpatients (27%) (P < 0.001). Coinfection was detected in 12% of hospitalized and 4% of outpatients (P < 0.031). HRV and adenovirus circulated throughout the entire year. RSV, influenza A and B predominated in winter, whereas metapneumovirus and parainfluenza predominated in spring. Of 362 patients with bronchiolitis, 84% had a virus identified; HRV (42%) and RSV (38%) were predominant. Of 77 patients with pneumonia, 84% had a virus detected with HRV (43%) and RSV (29%) predominating. CONCLUSIONS: HRV were significant pathogens associated with bronchiolitis and pneumonia, especially in hospitalized patients. Both, HRV and coinfections, were risk factors for hospitalization. These findings support the importance of including HRV detection in children with acute respiratory infection.

Rhinovirus detection by real-time RT-PCR in children with acute respiratory infection in Buenos Aires, Argentina.

Human rhinoviruses (HRV), the major cause of common colds, have a significant genetic diversity and are classified into 3 species (A, B, C) with more than 100 serotypes. HRV species C, described in 2006, can only be detected using molecular methods. The objectives of this paper were to adapt a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for HRV detection and to further determine the frequency of HRV in respiratory samples from children under 2 years of age, with acute respiratory infection (ARI), from Buenos Aires, Argentina. Two real-time RT-PCR assays amplifying the 207 base pair of the 5' non-coding region were compared. The original protocol includes locked nucleic acid analogues and a pyrimidine derivative in the forward primer, while the adapted protocol avoided those molecules. Of 67 respiratory samples, 17 (25.4 %) were positive with the original protocol, and 20 (29.9 %) with the adapted one. Discrepant results were confirmed by sequencing analysis. An expanded gold standard was defined to determine the performance of both assays, and was used to describe the clinical characteristics of positive patients. Better sensitivity and specificity were obtained with the adapted protocol. Considering the expanded gold standard, HRV were detected in 23/67 (34.3 %) patients with ARI: 8/18 (44.4 %) outpatients and 15/49 (30.6 %) hospitalized. Wheezing episodes were more frequent in HRV positive patients (43.5 %) than in HRV negative patients (18.2 %) (p = 0.041). This study describes the utility and clinical sensitivity of an adapted real-time RT-PCR assay for HRV detection.

Rhinovirus detection by real-time RT-PCR in children with acute respiratory infection in Buenos Aires, Argentina / Detección de rinovirus por RT-PCR en tiempo real en muestras respiratorias de niños de Buenos Aires, Argentina

Human rhinoviruses (HRV), the major cause of common colds, have a significant genetic diversity and are classified into 3 species (A, B, C) with more than 100 serotypes. HRV species C, described in 2006, can only be detected using molecular methods. The objectives of this paper were to adapt a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for HRV detection and to further determine the frequency of HRV in respiratory samples from children under 2 years of age, with acute respiratory infection (ARI), from Buenos Aires, Argentina. Two real-time RT-PCR assays amplifying the 207 base pair of the 5' non-coding region were compared. The original protocol includes locked nucleic acid analogues and a pyrimidine derivative in the forward primer, while the adapted protocol avoided those molecules. Of 67 respiratory samples, 17 (25.4 %) were positive with the original protocol, and 20 (29.9 %) with the adapted one. Discrepant results were confirmed by sequencing analysis. An expanded gold standard was defined to determine the performance of both assays, and was used to describe the clinical characteristics of positive patients. Better sensitivity and specificity were obtained with the adapted protocol. Considering the expanded gold standard, HRV were detected in 23/67 (34.3 %) patients with ARI: 8/18 (44.4%) outpatients and 15/49 (30.6 %) hospitalized. Wheezing episodes were more frequent in HRV positive patients (43.5 %) than in HRV negative patients (18.2 %) (p = 0.041). This study describes the utility and clinical sensitivity of an adapted real-time RT-PCR assay for HRV detection.

Los rinovirus humanos (RVH) constituyen la principal causa de resfrío común y poseen una gran diversidad genética, con más de 100 serotipos clasificados en tres especies (A, B, C). Los RVH C fueron descritos en 2006 y solo pueden detectarse utilizando métodos moleculares. El objetivo del presente trabajo fue adaptar un protocolo de transcripción reversa seguida de reacción en cadena de polimerasa (RT-PCR) en tiempo real para detectar RVH y posteriormente determinar su frecuencia en muestras de niños menores de 2 años con infección respiratoria aguda (IRA). Se compararon dos protocolos de RT-PCR en tiempo real, que amplifican 207 pares de bases de la región 5' no codificante. El protocolo original incluyó un cebador directo con análogos de nucleótidos bloqueados (LNA) y un derivado pirimidínico en su secuencia, mientras que el protocolo adaptado no los incluyó. De 67 muestras, 17 (25,4 %) fueron positivas con el protocolo original y 20 (29,9 %) con el protocolo adaptado; los resultados discrepantes se confirmaron por secuenciación. Se definió un gold standard expandido para determinar el desempeño de ambos ensayos y describir las características clínicas de los pacientes RVH positivos. La mejor sensibilidad y especificidad se obtuvo con el protocolo adaptado. Considerando el gold standard expandido, se detectó RVH en 23/67 (34,3 %) pacientes con IRA: 44,4 % (8/18) ambulatorios y 30,6 % (15/49) internados. Los episodios de sibilancias fueron más frecuentes en pacientes RVH positivos (43,5 %) que en RVH negativos (18,2 %) (p = 0,041). El presente estudio describe la utilidad y la sensibilidad clínica de esta RT-PCR en tiempo real adaptada para detectar RVH.

Rinovirus: Frecuencia en niños con infección respiratoria aguda, no internados / Rhinoviruses: Frequency in nonhospitalized children with acute respiratory infection

Los métodos moleculares para diagnosticar rinovirus humanos (RVH) han aumentado la sensibilidad de detección. Esto ha permitido documentar la asociación entre los RVH y las infecciones respiratorias agudas (IRA) altas y bajas. La infección por RVH durante la infancia se asoció con posterior desarrollo de asma. Se estudió la frecuencia de RVH en 186 niños menores de 6 años ambulatorios con IRA (alta o baja), durante 2 años consecutivos (1/6/2008 - 31/5/2010). Se correlacionó la presencia de RVH con los antecedentes y características clínico-epidemiológicas. La detección de RVH se realizó con una RT-PCR en tiempo real que amplifica parte de la región 5' no codificante del genoma. Los virus respiratorios clásicos se estudiaron por inmunofluorescencia. En el 61% de los niños se detectó etiología viral. Las frecuencias fueron: RVH 27%, virus sincicial respiratorio (VSR) 16%, influenza A y B 9%, parainfluenza 8%, metapneumovirus 7% y adenovirus 0.5%. Se observaron coinfecciones duales en 8 casos, siendo RVH el más frecuente (en 4 de ellos). Los RVH circularon durante todo el período estudiado, con picos en invierno y primavera. No se observaron diferencias clínico-epidemiológicas significativas entre pacientes con o sin RVH, excepto un mayor porcentaje de niños afebriles con RVH. Los RVH fueron los virus más detectados en niños ambulatorios, principalmente en menores de 2 años, los segundos virus asociados a bronquiolitis, luego del VSR, y detectados tres veces más en los niños expuestos a tabaquismo pasivo (OR: 2,91; p = 0.012) que en el resto. Fueron identificados como único agente en el 28% de las bronquiolitis.

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5' non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.

[Rhinoviruses. Frequency in nonhospitalized children with acute respiratory infection]. / Rinovirus. Frecuencia en niños con infección respiratoria aguda, no internados.

Molecular methods for human rhinoviruses (HRV) have increased the sensitivity in their diagnosis. HRV may cause acute respiratory infections (ARI) of the upper and lower respiratory tract. HRV infection during childhood is a predictor of asthma development. In this study, the HRV frequency in outpatient children with ARI was determined, and their clinical features and previous conditions were evaluated. A total of 186 respiratory samples of children under 6 year old attending the CEMIC pediatric emergency room from June 1, 2008 to May 31, 2010, were studied. Classical respiratory viruses were detected by immunofluorescence. A real time RT-PCR that amplifies part of the 5' non coding genomic region was used for HRV detection. Viral detection was obtained in 61% of children. The frequency was: 27% for HRV, 16% for respiratory syncytial virus (RSV), 9% for influenza, 8% for parainfluenza, 7% for metapneumovirus and 0.5% for adenovirus. Dual coinfection was detected in 8 children and HRV were the most frequent, detected in 4 of them. HRV circulated during the two year period of the study, with peaks during winter and spring. No clinical difference was observed between patients with or without HRV, except an increase percent of children with HRV without fever. HRV were the most frequent viruses detected in this population, mainly in children under 2 year old, the second cause of bronchiolitis after RSV and more frequently detected in children exposed to passive smoking (OR = 2.91; p = 0.012), and were detected as the sole etiologic agent in 28% of bronchiolitis.

[Acute viral respiratory infection in children under 5 years: Epidemiological study in two centers in Buenos Aires, Argentina]. / Infección respiratoria aguda viral en niños menores de 5 años: Estudio epidemiológico en dos centros de Buenos Aires, Argentina.

INTRODUCTION: Acute respiratory infections (ARI) are a major cause of hospitalization particularly at the extreme ages of life. OBJECTIVES: To determine the viral diagnosis in children < 5 years old with ARI, seasonality, clinical and epidemiological characteristics. POPULATION AND METHODS: A cross-sectional, descriptive and multicenter study was performed. Respiratory samples from patients with ARI hospitalized or outpatients with < 5 days of respiratory symptoms from June 2008 to May 2009 were studied for respiratory viruses. Clinical and demographic data were recorded. RESULTS: A total of 347 patients were enrolled: 234 hospitalized and 112 outpatients. Hospitalized patients were younger compared with outpatients (8 vs. 19 months, p <0.001) and presented more frequently bronchiolitis (74% hospitalized vs. 24% outpatients) and pneumonia (14% hospitalized vs. 5% outpatients). Age was statistically associated with hospitalization (p= 0.01). Viral diagnosis was achieved in 81% hospitalized and 57% of outpatients. Rhinovirus was the most frequent followed by respiratory syncytial virus. The rest of respiratory viruses were observed with lower frequency. Viral circulation was observed throughout the whole year. The median length of stay was 3.5 days. Intensive care was required in 11% of hospitalized patients and 3% required mechanical ventilation. No deaths were recorded. CONCLUSIONS: The use of viral diagnostic techniques allowed the identification of an etiologic agent in most of the hospitalized patients and more than half of outpatients. The addition of RT-PCR for rhinovirus, allowed the identification of this etiologic agent. Viral circulation was observed throughout the whole year. Hospitalized patients presented bronchiolitis and pneumonia more frequently than outpatients.

Infección respiratoria aguda viral en niños menores de 5 años: Estudio epidemiológico en dos centros de Buenos Aires, Argentina / Acute viral respiratory infection in children under 5 years: Epidemiological study in two centers in Buenos Aires, Argentina

Introducción. Las infecciones respiratorias agudas (IRA) son la mayor causa de hospitalización en edades extremas de la vida. Objetivos. Identifcar los agentes etiológicos de IRA viral en niños < 5 años hospitalizados y ambulatorios; describir estacionalidad y características clínico-epidemiológicas de la enfermedad. Población y métodos. Estudio descriptivo, transversal y multicéntrico en dos centros privados de Buenos Aires, en niños con IRA alta y baja. Se registraron antecedentes, cuadros clínicos y estudios virológicos. Resultados. Se estudiaron 347 pacientes: 235 hospitalizados; 112 ambulatorios. Los hospitalizados fueron menores que los ambulatorios (8 vs. 19 meses, p <0,001), presentaron más frecuentemente bronquiolitis (74% hospitalizados vs. 24% ambulatorios) y neumonía (14% hospitalizados vs. 5% ambulatorios). Solo la edad se asoció signifcativamente a hospitalización (p= 0,01). Se identifcó etiología viral en 81% de los hospitalizados y 57% de los ambulatorios. El virus más frecuente fue rinovirus seguido por virus respiratorio sincicial. Se observó circulación viral durante todo el año, especialmente en otoño e invierno. En pacientes hospitalizados, la mediana de hospitalización fue 3,5 días. Requirieron cuidados intensivos 25 (11%) pacientes, y 7 (3%) recibieron asistencia ventilatoria mecánica. No hubo letalidad. Conclusiones. Las técnicas de diagnóstico virológico permitieron identifcar agentes etiológicos en la mayoría de los pacientes hospitalizados y en más de la mitad de los ambulatorios con IRA. La incorporación de RT-PCR para rinovirus, permitió la identifcación de este agente etiológico. La circulación viral se observó a lo largo de todo el año. La bronquiolitis fue causa de internación en 174/201 (86,5%) niños con IRA y la neumonía en 33/39 (84,6%) niños.

Introduction. Acute respiratory infections (ARI) are a major cause of hospitalization particularly at the extreme ages of life. Objectives. To determine the viral diagnosis in children < 5 years old with ARI, seasonality, clinical and epidemiological characteristics. Population and methods. A cross-sectional, descriptive and multicenter study was performed. Respiratory samples from patients with ARI hospitalized or outpatients with < 5 days of respiratory symptoms from June 2008 to May 2009 were studied for respiratory viruses. Clinical and demographic data were recorded. Results. A total of 347 patients were enrolled: 234 hospitalized and 112 outpatients. Hospitalized patients were younger compared with outpatients (8 vs. 19 months, p <0.001) and presented more frequently bronchiolitis (74% hospitalized vs. 24% outpatients) and pneumonia (14% hospitalized vs. 5% outpatients). Age was statistically associated with hospitalization (p= 0.01). Viral diagnosis was achieved in 81% hospitalized and 57% of outpatients. Rhinovirus was the most frequent followed by respiratory syncytial virus. The rest of respiratory viruses were observed with lower frequency. Viral circulation was observed throughout the whole year. The median length of stay was 3.5 days. Intensive care was required in 11% of hospitalized patients and 3% required mechanical ventilation. No deaths were recorded. Conclusions. The use of viral diagnostic techniques allowed the identifcation of an etiologic agent in most of the hospitalized patients and more than half of outpatients. The addition of RT-PCR for rhinovirus, allowed the identifcation of this etiologic agent. Viral circulation was observed throughout the whole year. Hospitalized patients presented bronchiolitis and pneumonia more frequently than outpatients.