Correlation Between Drug-Resistance and Clinical Treatment of Mycoplasma Pneumoniae

Objective To explore the effectiveness and safety of azithromycin sequential therapy for children with Mycoplasma pneumoniae (MP) infection, and analysis correlation of drug-resistance with indisciplined used of macrolide antibiotics application. Methods According to MP antibody titers 1: 320 for MP infection as standard to clinical diagnosis MP-IgM positive. From March 2011 to February 2013, a total of 792 children(screened 5-13 years old) with upper respiratory infection complicating cough or(and) fever who suspected MP infected were recruited. Among them 431 cases MP-IgM positive were as subjects. According to differences frequency of macrolide antibiotics application and frequency of MP infection in one year, 431 children with MP positive were divided into experimental group (n=217) and control group (n=214) . Patients in experimental group were preliminary screening subjects who without MP infection and macrolide antibiotics applied history in half of a year. Patients in control group were repeated MP infected and indisciplined used of macrolide antibiotics≥2 times in one year. MP cultures of children in both groups were detected twice times when they admitted. If their culture MP positive, 23S rRNA V PCR product were synthesis, and drug sensitivity test to 9 kinds of antibiotics were detected. Children in experimental group whose positive culture MP antibiotics sensitivity and 23S rRNA V had no mutation were gave macrolides sequential therapy. In the end of 2 weeks after macrolides sequential therapy, detection MP cuture again. If their culture MP positive, analysed drug sensitivity and screened the 23S rRNA V mutation or not. At those two time points, the curative effects of azithromycin sequential therapy were judged . Analysed whether it had correlation between frequency of macrolide antibiotics irregular application and drug resistant in control group. Drug resistance, extrapulmonary complications and hospitalization time between two groups were analysis by statistics methods. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Guangdong Women and Children Hospital Affiliated Guangzhou Medical University. Informed consent was obtained from the parents of each participating participant. Results In this study the MP infection rate was 54.4%(431/ 792) . MP culture positive rate was 26.6% (115/ 431) in MP-IgM positive children. There had significance difference between experimental group and control group in MP resistant strain rates, and MP-resistant strain rate in experimental group were much lower than that in control group (χ2 =4.651 , P=0.041) . There had significance difference of frequency of indisciplined used of macrolide antibiotics in control group among 214 cases, and the higher frequency of indisciplined used of macrolide antibiotics, the higher rate of MP-resistant strain (χ2/χ2 trend value=22.056, 21.932; P<0.05) . A total of 14 children in experimental group whose positive culture MP antibiotics sensitivity and 23S rRNA V had no mutation were gave macrolides sequential therapy. There were 4 cases after treatment of 2 and 4 weeks, their MP acute detection results also positive. In the end of 2 and 4 weeks after macrolides sequential therapy, the curative effect was 71.42 %(10/ 14) . among of 4 cases, only one case sequencing result and shew 23S rRNA V had no mutation. Those 4 cases were gaven macrolides sequential therapy again. There were only one case after treatment of another 2 weeks MP acute detection results also positive. In the end of 4 weeks after macrolides sequential therapy, the curative effects of azithromycin sequential therapy was 92.85%(13/ 14) . There had significance difference between 14 cases positive culture MP of antibiotics sensitivity in experimental group and 37 cases MP-resistant strain in control group in incidence of extrapulmonary complications, and those incidence in experimental group was much lower than those in contral group (χ2 =4.443, P<0.05) . There had significance difference between two groups in hospitalization time, and hospitalization time in experimental group was much shorter than that in control group (χ2 =7.305, P<0.05) . Conclusions Azithromycin sequential therapy for children infected with MP is safe, effective, and does not induce drug resistant strains. Resistant strains can be induced by irregular application of macrolide antibiotics application, and resistance rate is positively correlated with the frequency of irregular applications them. Key words: Pneumoniae, Mycoplasma; Drug-resistance; Azithromycin; Sequential therapy; Child