BackgroundThe diagnosis of pertussis in clinical practice continues to be a challenge worldwide as the symptoms are variable. We aimed to determine the prevalence of pertussis in Chinese children irrespective of cough duration and explore the clinical characteristics of children with pertussis with different cough durations.MethodsThis was a prospective study of children 1month to 11years of age with different cough durations in one large Chinese hospital. Bilateral deep posterior nasopharyngeal swabs and venepuncture for full blood count, CRP and serology and sputum were obtained when possible for investigation. E-test strips were used for testing the susceptibility of the B.pertussis isolates against erythromycin, azithromycin, sulphamethoxazole/trimethoprim, levofloxacin, amoxicillin and doxycycline. Demographic, clinical and laboratory information on culture and antimicrobial susceptibility testing was collected from children, and analyzed using SAS v.10 (SAS Institute Inc., USA).ResultsAfter exclusions we analyzed 312 children. Ninety-seven (31.1%) children had laboratory evidence of pertussis. When grouped by cough duration, few characteristics were significant between children with and without pertussis. Of the 36 isolates, 72.2% (26/36)could not be inhibited by erythromycin and azithromycin at all. The MIC50 and MIC90 to amoxicillin were 0.75mg/L and 1mg/L respectively, sensitive to amoxicillin by the EUCAST points.ConclusionsThe one-size-fits-all clinical pertussis case definition is no longer optimal to recognize this disease. A large comprehensive study of children with all types of cough is required to make substantial inroads into increasing both the sensitivity and specificity in pertussis diagnosis, which will have a beneficial impact on public health. Amoxicillin maybe an alternative for children with marolide-resistant B.pertussis infection; however, local sensitivities are required to inform clinical practice.