ABSTRACT
Objective:To investigate drug resistance gene in Mycoplasma pneumoniae(MP) and the distribution of 13 respiratory pathogens in bronchoalveolar lavage fluid(BALF) of children with Mycoplasma pneumoniae pneumonia(MPP).Methods:A total of 100 BALF of children with MPP in Peking University Third Hospital and Peking University First Hospital from January 2018 to January 2019 were collected.Fluorogenic quantitative PCR was used to detect nucleic acid and it′s drug resistance gene of MP and multiple PCR method was adopted to detect influenza A virus, influenza A virus-H 1N 1, influenza A virus-H 3N 2, influenza B, human parainfluenza virus, adenovirus, human bocavirus, human rhinovirus, Chlamydia pneumoniae, human metapneumovirus, MP, human coronavirus, and respi-ratory syncytial virus gene, and the results were compared by using Chi square test. Results:In 100 BALF samples, MP and drug resistance gene were detected by fluorogenic quantitative PCR.Totally, 83 cases (83.00%) were MP positive and 78 cases (93.98%) were drug resistant.All of them had the point mutations A2063G in V region of 23S rRNA domain.A total of 13 kinds of respiratory pathogens were detected by multiplex PCR method, and 89 cases (89.00%) were positive.Totally, 79 cases (79.00%) were MP positive, of which 74 cases (74.00%) detected only MP, and 5 cases (5.00%) detected MP combined with other pathogens.Other pathogens were detected in 10 cases (10.00%). The virus detection rate of 0-4 years old group was higher than that of >4-6 years old group ( P=0.042) and >6 years old group ( P=0.002), and the differences were statistically significant. Conclusions:MP can be detected in most BALF samples of MPP children, the drug resistance phenomenon is serious, and the main point mutation is A2063G.There were other respiratory pathogens and 2 or 3 pathogens were detected in a small number of BALF samples.
ABSTRACT
Objective:To understand the pathogen distribution of children with influenza in North China in the past 2018-2019 years, and compare the accuracy of influenza virus antigen test results with that of influenza virus nucleic acid test results, provide reference data for clinical use good influenza virus pathogen detection methods.Methods:Five hundred and eighty throat swab samples of influenza-like children in 10 hospitals, northern China, were collected from December 2018 to January 2019.Each sample was tested by rapid influenza diagnostic test and reverse-transcription polymerase chain reaction(RT-PCR).Results:Of all 580 clinical samples, 256 positive samples (256/580 cases, 44.14%)were detected by the influenza rapid influenza diagnostic test, of which 235 were pure influenza A(235/256 cases, 91.8%), 21 cases were pave influenza B(21/256 cases, 8.2%), and 324 case were negative samples(324/580 cases, 55.86%). No cases were detected positive A and B at the same time.Of all 580 samples were detected using the A /B influenza virus RT-PCR, and a total of 353 cases(353/580 cases, 60.9%) were positive (of which 242 cases were influenza virus antigen-positive), of which 311 were pure A influenza(311/353 cases, 88.1%) and 41 were pure B influenza(41/353 cases, 11.6%), 1 case of mixed infection of A and B(1/353 cases, 0.3%), and 227 cases were negative(227/580 cases, 39.1%). In 324 cases of influenza virus antigen negative samples, 111 cases(111/324 cases, 34.3%) were positive for influenza virus nucleic acid.The detection rate of influenza A in Taiyuan was 23.2% (22/95 cases), and the detection rate of influenza B was 43.2% (41/95 cases), which was significantly different from other regions.With reverse-transcription polymerase chain reaction detection as the standard, the diagnostic value of influenza pathogen detection reagents was evaluated.The sensitivity, specificity, missed diagnosis rate, misdiagnosis rate, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Youden index and area under the receiver operating characteristic curve were 68.56%, 93.83%, 31.44%, 6.17%, 94.53%, 65.74%, 11.12, 0.335, 0.624 and 0.812.Conclusions:From December 2018 to January 2019, the majority of children′s influenza in northern China is influenza A virus.Except Taiyuan which is dominated by influenza B. Influenza virus nucleic acid detection has high sensitivity and specificity for diagnosing influenza, and also has the ability to distinguish virus subtypes.Influenza virus antigen detection has a certain diagnostic value, a good specificity (93.83%), sensitivity (68.56%) which needs to be further improved, and a certain rate of missed diagnosis (31.44%) needs to be paid attention to possible missed diagnosis.Detecting positive cases of influenza virus antigens should be given a fast and effective anti-viral treatment, while the negative cases, especially those at high risk for influenza complications, should be confirmed influenza virus RT-PCR as soon as practical.