Nasopharyngeal Isolates from a Cohort of Medical Students with or without Pharyngitis

Abstract

Objectives: Few studies have investigated pharyngeal colonisation in the United Arab Emirates (UAE). This study aims to identify the pharyngeal organisms present in a cohort of medical students with and without symptomatic pharyngitis. Methods: This study was conducted between September 2016 and June 2018 at the College of Medicine and Health Sciences, UAE University, Al-Ain. Nasopharyngeal swabs were collected from preclinical and clinical medical students attending the college during the study period. The specimens were tested for 16 viral and nine bacterial pathogens using a real-time polymerase chain reaction assay. Results: A total of 352 nasopharyngeal swabs were collected from 287 students; of these, 22 (7.7%) had pharyngitis symptoms. Overall, the most common isolates were human rhinovirus, Streptococcus pneumoniae and Haemophilus influenzae, with no significant differences in terms of gender, year of study or stage of study. The prevalence of S. pyogenes in asymptomatic and symptomatic students was 1.1% and 0%, respectively. A Centor score of ≥2 was not associated with S. pyogenes-positive samples. Six pathogens were isolated from symptomatic students including H. influenzae. Fusobacterium necrophorum was not detected in any of the samples. Conclusion: The diagnosis and management of pharyngitis should be tailored to common pathogens in the region. This study found that S. pyogenes and F. necrophorum were not detected among students with symptoms of pharyngitis; moreover, Centor scores of ≥2 were not associated with the presence of S. pyogenes. This cut-off score therefore should not be employed as an empirical measure to initiate penicillin therapy in this population.

Keywords: Pharyngitis; Pharynx; Asymptomatic Infections; Carrier State; Fusobacterium necrophorum; Streptococcus pyogenes; Penicillins; United Arab Emirates.