Year: 2010
Type: dissertation
Abstract: Acute respiratory tract infections (ARTIs), are the most common infections in man, and\nrepresent a major global health burden. Viruses, most often causing a mild and self-limiting\ndisease, yet with substantial morbidity and high costs for society, mainly cause upper\nrespiratory tract infections. 70% of all infections in primary care in Sweden are due to ARTIs.\nLower respiratory infections on the other hand constitute the third leading cause of death\nworldwide, mainly in children <5 years of age in resource poor settings. Distinguishing virus\nfrom bacteria can be difficult, and often lead to an over-prescription of antibiotics. Modern\nmolecular based diagnostic methods have increased the possibility of an etiologic diagnosis of\nARTIs significantly. This thesis aims to evaluate the use of a multiplex real time PCR assay\ntargeting 13 respiratory viruses and two bacteria, from a clinical perspective.\nIn paper I, a retrospective study of 954 nasopharyngeal samples, the PCR assay, which is\nbased on automated specimen extraction and multiplex amplification, is described. Detection\nrate was 48%. Streamlined testing and cost limitation (€ 33 per sample) along with high\naccuracy and prompt result delivery, is key to successful implementation of broad molecular\ntesting.\nPaper II evaluates in a prospective study of 209 adults with ARTI in primary care, and 100\nasymptomatic controls, the impact duration of symptoms have on detection rate. Overall\npositive yield was 43% in patients and 2% in controls, with a significantly higher detection\nrate in patients with < 6 days duration of symptoms (51%) compared to ≥ 7 days (30%,\np<0.01).\nHaving access to the PCR assay reduced antibiotic prescription rates by 50%, in a prospective\nstudy (paper III) of 426 adults with ARTI. Patients receiving a result within 48 hours were\nprescribed antibiotics in 6,8% (n=14) compared to 15.1% (n=33, p<0.01) in the delayed result\ngroup.\nThe diagnostic yield in paper IV, a retrospective study of 8753 patients of all ages during 36\nconsecutive months, was significantly higher during winter (54.7%) than in summer (31.1%,\np<0.001), and in children (61.5%) compared with adults (30.5%, p<0.001). Rhinovirus was\nthe most frequently found virus (32.5%), independent of season, and displayed a high genetic\nvariability across seasons.\nThe findings of this thesis support the implementation of similar methods in routine clinical\ncare.
Author: Robin Brittain-Long
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funder: Göteborgs Läkaresällskap
OpenAlex ID: W1542671060