Abstract

There is a close correlation between asymptomatic oropharyngeal colonization by bacterial pathogens and paediatric respiratory diseases. Evaluation of the frequency of asymptomatic carriers of Neisseria meningitidis and Moraxella catarrhalis in healthy children was the main aim of the current study. In this cross-sectional study, 123 oropharyngeal swabs were collected from children between 2 and 6 years old in kindergartens of Ilam, Iran. Moraxella catarrhalis and N. meningitidis were identified using phenotypic and genotypic assays. In addition, the occurrence of the virulence factors (ctrA and uspA1) and iron uptake (tbpA) genes was evaluated by PCR. Results showed that 21 M. catarrhalis isolates and 17 N. meningitidis isolates were identified by conventional microbiological and biochemical methods, but the RT-PCR assay detected that 18 and 8 isolates were positive for M. catarrhalis and N. meningitidis, respectively. The tbpA gene was positive in all N. meningitidis and M. catarrhalis isolates. Seven isolates were positive for the ctrA gene in N. meningitidis and seven isolates were positive for the uspA1 gene in M. catarrhalis. These pathogenic bacteria often occurred as asymptomatic carriage of N. meningitidis in children from large families with low economic status, which reflects the importance of the environment and socio-economic level of families in the distribution of these potentially pathogenic bacteria in the oropharynx of children. Monitoring for the carriage of potential pathogenic bacteria in the nasopharynx of healthy children is important as this can predispose to infectious diseases; common exposure to human respiratory bacterial pathogens is a further risk factor.