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Background: Acute respiratory infections (ARI) are a leading cause of morbidity and mortality worldwide. There is a need to demonstrate the clinical impact of using the new, rapid and sensitive molecular assays in prospectively designed studies., Objectives: To study the impact on medical management of a rapid molecular assay in patients with respiratory infections., Study Design: A prospective, randomized, non-blinded study was performed in patients presenting to the Emergency Department during two respiratory seasons (2016-2017). Diagnosis was performed by FilmArray Respiratory Panel (FilmArray-RP) or by immunofluorescence assay (IFA)., Results: A total of 432 patients (156 children and 276 adults) were analyzed. Diagnosis with FilmArray-RP was associated with significant changes in medical management including withholding antibiotic prescriptions (OR:15.52, 95%CI:1.99-120.83 in adults and OR:12.23, 95%CI:1.56-96.09 in children), and reduction in complementary studies in children (OR:9.64, 95%CI:2.13-43.63) compared to IFA. Decrease in oseltamivir prescriptions was significantly higher in adults in the FilmArray-RP group (p = 0.042; OR:1.19, 95%CI:0.51-2.79) compared to adults managed with IFA. Diagnostic yield was significantly higher by FilmArray-RP (81%) than by IFA (31%)(p < 0.001). The median time from sample collection to reporting was 1 h 52 min by FilmArray-RP and 26 h by IFA (p < 0.001)., Conclusions: The high respiratory viruses' detection rate and availability of results within two hours when using FilmArray-RP were associated with decreases in antibiotic prescriptions and complementary studies and more accurate use of oseltamivir., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

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.

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.

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.

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.

Background: Influenza virus is the most common cause of influenza-like illness (ILI) in adults. In Argentina, studies on influenza and other respiratory viruses were performed mostly in pediatric populations., Objectives: To determine: (1) the frequency of influenza virus and other common respiratory viruses in adult outpatients with ILI, (2) whether the signs and symptoms predict viral etiology, (3) whether viral diagnosis changes clinical management or infection control measures and (4) to characterize the influenza strains circulating in the community., Population and Methods: Nasal and pharyngeal swabs from adult outpatients with ILI attending the emergency room during the winter seasons of 2004 and 2005 in Argentina were evaluated by immunofluorescence and RT-PCR., Results: Of 151 samples analyzed, 39 (26%) were influenza A positive, 5 (3.3%) influenza B positive and 4 (2.6%) respiratory syncytial virus positive by immunofluorescence. Two samples (1.3%) were human metapneumovirus positive by RT PCR. Cell culture detected six additional influenza viruses and one adenovirus positive sample. The sensitivity of immunofluorescence for influenza compared with culture was 70%. Symptoms did not predict etiology., Conclusions: In this study, 40% of the patients with ILI had a specific viral infection and 83% were influenza viruses. Viral detection was necessary to determine the etiology as signs and symptoms were not different between patients with or without viral infection. Viral diagnosis was important to implement infectious control measures. Circulating influenza strains in this study were similar to the correspondent vaccine strains selected for the Southern hemisphere.

Adenovirus (AdV) respiratory infections have usually been associated with species B, C, and E. In this study, we detected 9.4% of AdVs by PCR in 500 nasal swabs from 319 children with influenza-like symptoms. AdV typing by PCR with specific probes showed species C, B, and F as well as coinfection with two species. Coinfection with two AdV species and the presence of species F in respiratory samples are novel findings that should be further investigated.

Human metapneumovirus (hMPV) is a virus, which was first associated with acute lower respiratory infection in children but is detected currently in all age groups. Clinical symptoms are similar to those described for respiratory syncytial virus (RSV) infections, ranging from mild respiratory illness to severe bronchiolitis and pneumonia in children. To date, no cases of hMPV have been reported in Argentina. In this study, 440 respiratory samples obtained during the period 1998-2002 from children under 5 years old with acute respiratory infection were evaluated. Routine detection for RSV, adenovirus, influenza, and parainfluenza was undertaken by immunofluorescent assay. Of the samples negative for these viruses, only 100 were available. All these samples were tested for hMPV by RT-PCR using primers for the L gene. Eleven out of 100 (11%) respiratory samples were positive for hMPV by RT-PCR. A higher frequency of detection was observed in spring. hMPV was detected in all the years studied, except in 2001. Ten out of 11 children positive for hMPV were hospitalized. Median age was 5 months. Of seven patients, five (71%) required oxygen supplementation. The most frequent diagnosis was bronchiolitis (86%), sometimes accompanied by conjunctivitis and otitis media. The present study showed that hMPV was associated with acute lower respiratory infections in children in Buenos Aires, Argentina. This evidence strongly suggests that hMPV is a common pathogen with a wide geographical distribution, which should be included in the routine diagnosis of respiratory viruses in young children., (Copyright 2004 Wiley-Liss, Inc.)

Background: Adenoviruses are the second most prevalent cause of acute lower respiratory infection of viral origin in children under four years of age in Buenos Aires, Argentina. The purpose of this study was to analyze the clinical features and outcome of acute lower respiratory infection associated with different adenovirus genotypes in children., Methods: Twenty-four cases of acute lower respiratory infection and adenovirus diagnosis reported in a pediatric unit during a two-year period were retrospectively reviewed. Adenovirus was detected by antigen detection and isolation in HEp-2 cells. Adenovirus DNA from 17 isolates was studied by restriction enzyme analysis with Bam HI and Sma I., Results: Subgenus b was found in 82.3% of the cases, and subgenus c in 17.7%. Within subgenus b, only genotype 7 was detected, with genomic variant 7h in 85.7% (12/14) and genomic variant 7i in 14.3% (2/14). Mean age was 8.8 +/-; 6 months, and male to female ratio was 3.8: 1. At admission, pneumonia was observed in 71% of the cases and bronchiolitis in 29%. Malnutrition occurred in 37% of the cases; tachypnea in 79%; chest indrawing in 66%; wheezing in 58%; apneas in 16%; and conjunctivitis in 29%. Blood cultures for bacteria and antigen detection of other respiratory viruses were negative. During hospitalization, fatality rate was 16.7% (4 /24). Of the patients who died, three had Ad 7h and one Ad 7i. Thus, fatality rate for adenovirus type 7 reached 28.6% (4/14)., Conclusions: These results show the predominance of adenovirus 7 and high lethality associated with the genomic variants 7h and 7i in children hospitalized with acute lower respiratory infection.

This study describes the first multicentered study of acute lower respiratory infection viral etiology in young children from four different geographical areas of Argentina. A total of 1,278 children under 5 years of age, hospitalized in primary care centers from Buenos Aires, Córdoba, Santa Fé and Mar del Plata cities during a 2-year period were studied (1993-1994). Nasopharyngeal aspirates were investigated for respiratory syncytial virus (RSV), adenovirus, parainfluenza, and influenza A and B viruses by indirect immunofluorescence. Out of the patients studied, 946 (74%) were under 1 year of age. Viruses were detected in 399 patients (32%). RSV was observed in 25.3% of the samples, representing 78.2% of all viral positive cases. Adenoviruses were detected in 2.5% of the cases, parainfluenza in 2.2%, influenza A in 2.1%, and influenza B in 0.2%. Compared with other viruses, the higher RSV frequency was statistically significant (P < 0.000). Most RSV cases were detected between May and September with a significant peak in July (P < 0.000). Pneumonia was observed in 46% of the patients, bronchiolitis in 41% and other entities in 13%. The case fatality rate observed during the 2 year study was 0.73%. Most of the above respiratory viruses were detected in the four cities, however, the frequency of RSV and influenza were different in the southern city., (Copyright 2001 Wiley-Liss, Inc.)

The frequency of respiratory syncytial virus (RSV) and the distribution of subgroups A and B strains during 7 consecutive years (1990-1996) were examined in two cities of Argentina. Nasopharyngeal aspirates from 1,304 children less than 2 years of age hospitalized with acute lower respiratory infection were studied by indirect immunofluorescence. RSV was detected in 352 cases (26.9%), and the peak activity was observed in midwinter. Subgroup characterization was performed with two monoclonal antibodies against the F protein on nasopharyngeal aspirate smears. Of 195 samples, 174 (89.2%) were identified as subgroup A strains and 21 (10.8%) as subgroup B. Both strains cocirculated during 5 of 7 years studied with subgroup A predominating. Subgroup A occurred at least 8 times as often in all years except for 1994-1995. Children infected by subgroup A were younger than those infected by subgroup B (P < 0.05). The association of subgroup A infection with bronchiolitis and subgroup B with pneumonia was statistically significant (P < 0.03)., (Copyright 2000 Wiley-Liss, Inc.)

Background: Adenoviruses are the second cause of acute lower respiratory infection (ALRI) of viral origin in small children from Buenos Aires, Argentina., Objective: The aim of this study was to characterize, by restriction enzyme analysis, 17 adenovirus strains isolated from the nasopharyngeal aspirates of children under 2 years of age hospitalized due to ALRI., Study Design: Seventeen adenovirus strains isolated between May 1991 and December 1992 in one hospital of Buenos Aires were studied. Adenoviruses were amplified in HEp-2 cells and viral DNA was studied with the restriction enzymes Bam HI and Sma I., Results and Conclusions: Eighty two percent (14/17) of the isolates were classified as adenoviruses from subgenus b and 17.7% (3/17) belonged to subgenus c. Genome type 7 h was detected in 85.7% (12/14) and 7 i in 14.3% (2/14) of the strains from subgenus b. The case lethality associated with adenovirus genome type 7 was 28.6% (4/14 cases). Three fatal cases corresponded to Ad 7 h and one to Ad 7i. Ad 7h shows a high prevalence in small children hospitalized with ALRI and is associated with a high fatality rate.

A collection of 165 adenovirus strains isolated from nasopharyngeal aspirates of children hospitalized for acute lower respiratory infection in Argentina, Chile, and Uruguay between 1991 and 1994 was studied by restriction enzyme analysis (work performed in the Department of Virology, University of Umeå). Of the isolates, 71% (n = 117) were identified as members of subgenus B. Of these, 101 (61.2%) corresponded to genome type 7h, four (2.4%) to genome type 3p2, four (2.4%) to genome type 11a, one (0.6%) to genome type 7b, and one (0.6%) to genome type 7c. Two isolates that were neutralized as serotype 3 and four isolates that were neutralized as serotype 7 exhibited novel BamHI cleavage profiles corresponding to three new genome types denominated 3x, 7i, and 7j. Subgenus C members represented 28.5% of all typed isolates. Five different genome types of Ad1, seven genome types of Ad2, and three genome types of Ad5 were identified of, which two, two, and one, respectively, were found to correspond to new DNA variants. Only one isolate (0.6%) corresponded to Ad4 of subgenus E. Ad7h was isolated from 17 of the 18 fatal cases recorded among the patients included in the study.

Forty-nine of 255 (19.2%) Argentinean children between the ages of 1 and 18 months without evidence of viral or bacterial infections, but with clinical and radiologic evidence of acute lower respiratory distress, had serologic evidence of recent Chlamydia trachomatis infection by the demonstration of specific IgM, seroconversion or 4-fold rise in titer or elevated titers by enzyme immunoassay and the microimmunofluorescence test. Recent C. trachomatis infection was detected in 28 of 166 (16.9%) of children with bronchiolitis and 18 of 89 (20.2%) with pneumonia. Three additional children with bronchiolitis had Chlamydia pneumoniae-specific antibody. There was a significantly higher prevalence of C. trachomatis infection in children living in La Plata city orphanage (26 of 74, 35.1%) than in those attending 2 pediatric hospitals in Buenos Aires (23 of 181, 12.7%) (P less than 0.001). C. trachomatis infection was detected in all age groups up to 18 months. Thirty of 49 infections were in children older than 3 months of age and 16 were in children older than 6 months. These results suggest that C. trachomatis infection may be associated with bronchiolitis and pneumonia in children between the ages of 1 and 18 months of age in Argentina and that a proportion may be horizontally transmitted.