The pathogenic composition and molecular typing of hospitalized children with hand, foot and mouth disease in Tianjin in 2016

Objective To explore pathogenic composition of hand, foot and mouth disease (HFMD), and the molecular typing of enterovirus in Tianjin Children′s Hospital in 2016. Methods Single center study. A total of 327 samples of HFMD cases which collected from Tianjin Children′s Hospital from March to November in 2016 were tested for nucleotide acid of enterovirus(EV), human enterovirus 71(EV71), Coxsackievirus A 16 (CA16) by real-time reverse transcription polymerase chain reaction(RT-PCR), among which 104 sample of other EV positive were selected to amplify and sequence the whole VP1 region by using RT-PCR. Homology was analyzed and phylogenetic tree were constructed by comparison of the sequence with all subgenotype of EV by Chromas1.62 and MEGA6.06. EV positive rate in different age groups were compared by SPSS20.0. Results Of all the 327 HFMD cases tested, there were 272 EV positive cases, the constituent ratio of EV71, CA16 and other EV were 55.1% (150/272), 6.6%(18/272) and 38.2% (104/272)respectively. The EV positive rates of different age groups (69.0%-90.9%) were different significantly(χ2=15.897, P=0.044), the 3 years-old-group had the highest EV positive rate than that of the other age groups (90.9%, 40/44). Of all 104 samples of other EV tested, 34 were CA10 (12.5%) and 14 were CA6 (5.1%). Phylogenetic analysis of 11 EV71 VP1 and 20 CA10 VP1 showed that the EV71 and CA10 strains belonged to genotype C4a and genotype G, respectively. Conclusions EV71 was still the predominant pathogen in spite of the constituent ratio of other EVs increased markedly in 2016 in Tianjin. It is important to enhance etiological monitoring for control and prevention of HFMD. (Chin J Lab Med, 2017, 40: 367-371)