Rol del rinovirus en niños hospitalizados con infección respiratoria aguda
Acute respiratory infections (ARIs), among which the most frequent pathologies\ninclude pneumonia, bronchiolitis and influenza-like illness, affect the whole, but\nespecially people under 5 and over 65. It is among the leading causes of mortality\nworldwide. In Argentina, ARIs are the leading cause...
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| Formato: | Tesis de maestría acceptedVersion |
| Lenguaje: | Español |
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Facultad de Farmacia y bioquímica
2014
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=afamaster&cl=CL1&d=HWA_1389 http://repositoriouba.sisbi.uba.ar/gsdl/collect/afamaster/index/assoc/HWA_1389.dir/1389.PDF |
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| Sumario: | Acute respiratory infections (ARIs), among which the most frequent pathologies\ninclude pneumonia, bronchiolitis and influenza-like illness, affect the whole, but\nespecially people under 5 and over 65. It is among the leading causes of mortality\nworldwide. In Argentina, ARIs are the leading cause for consultation and\nhospitalization in all ages, and in Santa Fe they accounted for nearly 20% of admissions\nat the local pediatric referral hospital in 2010. The most common IRA-causing viral\npathogens are respiratory syncytial virus (RSV), influenza, parainfluenza, adenovirus,\nmetapneumovirus, coronavirus and rhinovirus.\nHuman rhinovirus (HRV) belongs to the family Picornaviridae. They are nonenveloped\nspherical viruses and their genome is a single positive-sense RNA linear\nmolecule which is coated by a capsid of icosahedral symmetry. First isolated in 1956,\nover 100 different serotypes are currently known which are grouped into three\nspecies, HRVA, HRVB and HRVC. They are heat stable and can spread through\ncontaminated respiratory secretions through direct contact between people. They may\nbe found in people of all ages and are spread worldwide. Although their frequency of\ncirculation is usually higher in autumn and spring, they can be detected in every month\nof the year. While historically considered upper airways pathogens, they have recently\nbeen shown to cause infections in the lower respiratory tract as well, causing\nhospitalizations of children with pneumonia, bronchiolitis and chronic pulmonary\nobstruction. They are also associated with patients with recurrent episodes of\nwheezing, asthma exacerbations, bronchitis, sinusitis and acute otitis media.\nVirological diagnosis is needed to determine the etiology of ARIs, since the clinical\nsymptoms caused by each of these viruses are often similar. In addition, the\nunnecessary use of antibiotics can be thus restricted. Viral isolation in tissue culture\nfollowed by an acid liability test represents the standard method in the laboratory for\nconfirmation of HRV infection, but the time required is longer than two weeks, which\nis of limited value for therapeutic decision. Techniques based on the detection of\nnucleic acids through chain reaction (PCR) have led to advance in ARI identification.\nThe fact that no HRV-related studies have been conducted in Santa Fe so far led to\nthe completion of this work, which aims to select and optimize a PCR technique\nenabling the detection of the virus in ARI hospitalized pediatric patients during THE\nmarch 2010-february 2011 period, and then study their frequency, seasonality and\nepidemiology, as well as clinical and epidemiological aspects of infected patients.\nIn order to develop the study, a highly sensitive and specific nested RT-PCR was\nselected which was tested by Steininger et al. (2001) for most known HRV serotypes,\namplifying a highly preserved fragment of the viral genome. Technique was optimized\nwith positive virus controls, varying critical test parameters, and specificity was\nthereby confirmed by testing positive controls of other respiratory viruses.\nA total of 2020 nasopharyngeal aspirates (NPA) were obtained during the study\nperiod from patients who underwent antigen detection RSV, adenovirus, parainfluenza\nand influenza A and B by immunofluorescence (IF). Detection of influenza A and B was\nalso carried out through real time RT-PCR. For a representative proportion of NPAs\nwho were negative by IF (452 samples) HRV was determined through RT-PCR,\ndetecting the virus genome in 172. This resulted in a 38.1% positivity and a second place (8.5%) in the rate of respiratory virus flow. It was found in all months of the year,\npredominantly during March 2010 and from August to February 2011.\n60% of hospitalized children with HRV attributable to ARI were under 6 months,\nwith a median age of 4 months. Age proved not to be a risk factor for developing\nsevere disease. The proportion of infected children was similar for both genders.\nClinical and epidemiological aspects of 145 patients were analyzed. 31% had a\nmedical history, including prematurity (55.6 %) and recurrent wheezing (51.1%) as\nprevailing conditions. The most common discharge diagnoses were pneumonia\n(35.2%), bronchiolitis (32.4%) and bronchitis (12.4%). The aerial radiological findings\nobserved include (75.2%) trapping interstitial infiltrate (67.9 %) and alveolar infiltrates\n(35.8%). 72.7% of patients had leukocytosis. Antibiotics were used in 66.4 % of\ntreatments and 85.5% of the children required oxygen supply during hospitalization.\nThe median duration of hospital stay was 6 days and 15.9 % of patients required\nadmission to intensive care unit (ICU). No significant differences were observed\nbetween the age of ICU patients and that of patients who did not have severe clinical\nsymptoms. Similarly, having a clinical history did not prove a risk factor for developing\nsevere disease.\nThis study showed that HRVs are associated with ARI-induced children\nhospitalizations. The implementation of an RT-PCR endpoint technique could quickly\ndetect, with sensitivity and specificity, a virus that is the second in importance with\ngreatest circulation (after VSR), and will be capable of routinely reducing ARI cases of\nunknown origin, thus establishing the role these viruses play in our environment and\nfacilitating the choice of appropriate therapeutic approaches. |
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