Identification of Etiological Agents of Pertussis-Like Syndrome in Children Younger Than 5 Years Old Hospitalized in Southwestern Iran

Background: Despite the global vaccination program, there are many new cases of pertussis in different societies annually. Objectives: This study aimed to investigate the prevalence of some microorganisms associated with pertussis-like syndrome and compare the clinical presentations between Bordetella pertussis and pertussis-like syndrome in children. Methods: Children younger than 5 years old suspected of pertussis-like syndrome were admitted to a hospital in Ahvaz, Iran, and examined from July 2018 to July 2019. Nasopharyngeal samples were evaluated using molecular methods. The studied microorganisms were the following: B. pertussis, B. parapertussis, Mycoplasma pneumoniae, Chlamydophila pneumoniae, adenovirus, respiratory syncytial virus, and parainfluenza virus type III. Results: Forty-five children were enrolled. B. pertussis was detected in 15 cases (33.3%), respiratory syncytial virus in 14 (31.1%), C. pneumoniae in 3 (6.7%), and parainfluenza virus type III in 3 (6.7%). The collected samples were negative in terms of M. pneumoniae, adenovirus, and B. parapertussis. In the case of paroxysmal cough, the clinical symptoms were significantly different between pertussis and pertussis-like groups. Conclusions: The results indicated that children with pertussis-like syndrome are commonly infected with B. pertussis and respiratory syncytial virus, so more attention should be paid to this issue. The study also demonstrated the importance of molecular diagnosis methods, along with diagnosis based on clinical symptoms, in children suspected of pertussis-like syndrome.