Community-acquired pneumonia in Chile: the clinical relevance in the detection of viruses and atypical bacteria

Background Adult community-acquired pneumonia (CAP) is a relevant worldwide cause of morbidity and mortality, however the aetiology often remains uncertain and the therapy is empirical. We applied conventional and molecular diagnostics to identify viruses and atypical bacteria associated with CAP in Chile.\ud \ud Methods We used sputum and blood cultures, IgG/IgM serology and molecular diagnostic techniques (PCR, reverse transcriptase PCR) for detection of classical and atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumoniae) and respiratory viruses (adenovirus, respiratory syncytial virus (RSV), human metapneumovirus, influenza virus, parainfluenzavirus, rhinovirus, coronavirus) in adults >18 years old presenting with CAP in Santiago from February 2005 to September 2007. Severity was qualified at admission by Fine's pneumonia severity index.\ud \ud Results Overall detection in 356 enrolled adults were 92 (26%) cases of a single bacterial pathogen, 80 (22%) cases of a single viral pathogen, 60 (17%) cases with mixed bacterial and viral infection and 124 (35%) cases with no identified pathogen. Streptococcus pneumoniae and RSV were the most common bacterial and viral pathogens identified. Infectious agent detection by PCR provided greater sensitivity than conventional techniques. To our surprise, no relationship was observed between clinical severity and sole or coinfections.\ud \ud Conclusions The use of molecular diagnostics expanded the detection of viruses and atypical bacteria in adults with CAP, as unique or coinfections. Clinical severity and outcome were independent of the aetiological agents detected.This work was supported by the Fondo Nacional de Ciencia y Tecnología (FONDECYT) (grant number 1050734); and the Fondo Nacional de Investigación en Salud (FONIS) (grant number SA04 I 2084)

High seroprevalence of cytomegalovirus, herpes simplex type 1 virus and epstein barr virus infection among human immunodeficiency virus-infected adults Elevada seroprevalencia de citomegalovirus, virus herpes simplex tipo 1 y virus epstein barr en adultos

Background: Cytomegalovirus (CMV), herpes simplex type 1 (HSV-1) and Epstein Barr virus (EBV) are latent persistent infections. Their reactivation may cause illnesses and death in human immunodeficiency virus-infected (HIV) people. World wide seroprevalence of these viruses is over 50%. In Chile, information is not available. Aim: To determine the seroprevalence of CMV, HSV -1 and EBV in Chilean HIV- infected adults. Patients and Methods: A total of 400 HIV- infected adults aged 17 to 67 years (340 males) were studied during 2005 and 2006. CMV, HSV-1 and EBV serum antibodies were measured by enzyme-linked immunoabsorbent assay. Results: The mean lapse from the diagnosis of HIV and serum testing was 67 months and 69.5% patients received antiretroviral therapy. Sixty seven percent of the sample were men who had sex with men (MSM). The seroprevalence for CMV, HSV-1 and EBV were 98.5, 92.2 and 99.7%, respectively. No patient had negative antibodies for all three viruses. Male patients tha

Detection of human metapneumovirus in children hospitalized for acute lower respiratory infection in Santiago, Chile Detección de metapneumovirus humano en niños hospitalizados por infección respiratoria aguda baja en Santiago, Chile

Background: Human metapneumovirus (hMPV) has recently been described as a new causal agent of acute low respiratory infection (ALRI) in children. In South America, detection has been reported only in Brazil and Argentina. Aim: To detect hMPV in children hospitalized for ALRI in Santiago, Chile. Material and Methods: Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect N gene of hMPV in 182 nasopharyngeal aspirates that were negative for common respiratory viruses, obtained from children hospitalized for ALRI during 2003. Results: Ten samples (5.4%) were positive, most of them detected during spring months. Conclusions: Since hMPV was detected among infants with ALRI in Santiago, further studies on their prevalence should be done in South America

Cyclovirus in nasopharyngeal aspirates of Chilean children with respiratory infections

Some respiratory tract infections remain unexplained despite extensive testing for common pathogens. Nasopharyngeal aspirates (NPAs) from 120 Chilean infants from Santiago with acute lower respiratory tract infections were analysed by viral metagenomics, revealing the presence of nucleic acids from anelloviruses, adenovirus-associated virus and 12 known respiratory viral pathogens. A single sequence read showed translated protein similarity to cycloviruses. We used inverse PCR to amplify the complete circular ssDNA genome of a novel cyclovirus we named CyCV-ChileNPA1. Closely related variants were detected using PCR in the NPAs of three other affected children that also contained anelloviruses. This report increases the current knowledge of the genetic diversity of cycloviruses whose detection in multiple NPAs may reflect a tropism for human respiratory tissues

Apnea as a presenting symptom in human metapneumovirus infection Apnea como forma de presentación de una infección por metapneumovirus humano

Human metapneumovirus (hMPV), a recently described pathogen of lower respiratory tract infections (LRTI), has been detected in 5,4% of Chilean infants hospitalized for LRTI whom are negative for adenovirus, respiratory syncytial virus, influenza and parainfluenza viruses. hMPV may cause bronchiolitis or pneumonia in hospitalized patients, and ocassionally require admission to intensive care units and mechanical ventilation. The infection has been associated with apnea, especially in preterm infants. Nosocomial dissemination has also been described. We present the case of a one-month-of age premature infant with apnea, and infection caused by hMPV of probable nosocomial aquisition. Clinical features of hMPV infection are reviewed and its association with apnea and nosocomial transmission is discussed. hMPV should be included in the routine diagnosis of respiratory viruses in infants with apnea and should be considered among the respiratory pathogens associated with nosocomial transmiss

Genetic Variability of Human Metapneumovirus Isolated From Chilean Children, 2003-2004

Human metapneumovirus (hMPV) is a significant cause of acute lower respiratory tract infection in all age groups, particularly in children. Two genetic groups and four subgroups of hMPV have been described. They co-circulate during an epidemic in variable proportions. The aims were to characterize the genotypes of hMPV recovered from children hospitalized for acute lower respiratory tract infection and to establish the molecular epidemiology of strains circulating in Santiago of Chile during a 2-year period. The detection of the N gene by reverse-transcription polymerase chain reaction was carried out for screening 545 infants hospitalized for acute lower respiratory tract infection in Santiago during 2003-2004. The genetic typing of hMPV was performed by analyzing the fusion gene sequences. hMPV was detected in 10.2% (56/545 cases). Phylogenetic analysis of F gene sequences from 39 Chilean hMPV strains identified the two groups and four subgroups previously described. Strains clustered into group A were split further into the sub lineages A1, A2, and A3. Most Chilean strains clustered into the proposed novel A3 sub lineage (59%). A3 viruses were present in both years, while A1 and A2 circulated just in I year. In conclusion, hMPV is a relevant cause of acute lower respiratory infection in Chilean children and the potential novel cluster of group A emphasize the need for further regional genetic variability studies. J. Med. Virol. 81:340-344, 2009. (c) 2008 Wiley-Liss, Inc