Etiological characteristics of chlamydia trachoma conjunctivitis of Primary Boarding School students in the Qinghai Tibetan area

The aim of this study was to investigate the etiological characteristics of Chlamydia trachomatis conjunctivitis among resident students at primary schools in the Qinghai Tibetan area in order to understand the distribution of C. trachomatis and other pathogenic microorganisms, to detect the isolation rate of infectious pathogens, and to provide an evidence for further targeted efforts in the prevent of sporadic trachoma efforts. From two primary schools in Qinghai Province, ocular samples from 35 students who were clinically diagnosed as trachoma cases and 60 normal controls were obtained by swabbing their upper eyelids and lower conjunctival sacs. Samples were preserved at 4°C and airlifted to Beijing Tongren Hospital within 24 h. Real-time polymerase chain reaction(RT-PCR) was used to screen for C. trachomatis, and nested PCR was used to amplify a fragment of the omp A gene for serotype confirmation. Bacterial cultivation and sensitivity tests were conducted based on the 2015 version of the Clinical and Laboratory Standards Institute. Adenovirus, herpes simplex virus, cytomegalovirus, and Epstein-Barr virus were screened by RT-PCR. Among the 35 students with trachoma, 8 came from the Jianshetang Primary School and 27 came from the Central Primary School. Two novel C. trachomatis B serotypes(Gen Bank accession numbers KU737520 and KU737521) were detected based on a sequence analysis of the omp A gene. Single C. trachomatis infections accounted for 42.86%(9/21) of the cases, and infections with multiple bacteria, particularly Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, and Streptococcus pneumoniae, accounted for the remaining 57.14%(12/21). Of the 14 C. trachomatis-negative samples, one was positive for adenoviral infection(serotype D) and 13 were positive for bacterial infections(H. influenzae, M. catarrhalis, S. pneumoniae, S. aureus, streptococci other than S. pneumoniae, Staphylococcus epidermidis, Corynebacterium, and Arthrobacterium). In addition to C. trachomatis, the other bacteria and virus that were detected in the boarding students of primary schools in the Qinghai Tibetan area should be emphasized in trachoma prevention and control.