The Research Of Mycoplasma Pneumoniae Resistance To Macrolides

Objective To investigate the resistant rate of Mycoplasma pneumoniae (MP) to macrolide drugs; clinical features of the macrolide-resistant strains; factors of MP-resistance.Methods Fifty-seven Mycoplasma pneumoniae strains were isolated from pediatric patients in Shenzhen Children’s Hospital from November2010to July2011. After admission, throat swabs taking from the patients, were amplified by Polymerase chain reaction (PCR) sequencing to detect the macrolide-resistant gene.Acoording to the result, patients were divided into two groups. Pre-hospital use of antibiotics (especially macrolides), treatment response, course, illness, outcomes and other aspects in two groups of children were observed.Mp rapid culture and drug resistant tested in part of patients at the same time.Results Of the57patients,36patients harbored an A-to-G substitution at position2063, not found the mutation of2064points and the rate of resistance was63.16%(36/57). The total febrile days was longer in the macrolide-resistant group than in the macrolide-suspectible group(6.56±6.17days versus3.57±3.80days, P=0.05); the cough duration of the two groups showed no statistically significant difference(20.25±19.92days verse14.76±6.65days, P=0.228); there were eight strains of existing atelectasis in the macrolide-resistant group and only two strains in the macrolide-suspectible group; the total length of stay showed no significant difference(7.33±2.54days verse6.57±1.63days, P=0.223). There were also no statistically significant differences in macrolide administration days during hospitalization(5.19±3.01days verse4.05±1.83days, P=0.120). Follow-up for one month after discharge, nine cases of the macrolide-resistant group still presented cough, however only1had cough in the macrolide-suspectible group. No significant differences were found in sex(P=0.709), age(P=0.806), nasal congestion, runny nose, sore throat, sputum, wheezing, chest pain, shortness of breath, difficulty breathing and chills, between the two groups. For laboratory tests, the increasing rate of C-reactive protein was significantly higher in the macrolide-resistant group than in the macrolide-suspectible group(P<0.05).There were no statistically difference of the two groups in macrolide administration before hospitalization(P=0.259). There were47cases done the Mp rapid culture and drug resistant test at the same time.29cases had the2063point genetic mutation,18cases without genetic mutation. Among the29cases, there were4macrolide-resistant cases according to the rapid test; among the18cases without genetic mutation, there were8macrolide-resistant cases according to the rapid test; neither resistant gene, nor the rapid culture detecting macrolide-resistant was only one case.Conclusion The rate of MP resistance to macrolide is lower than the rate reported in Beijing and Shanghai. The febrile days and increasing rate of C-reactive protein in the macrolide-resistant group were significantly higher than that of macrolide-suspectible group. The rate of MP resistance to macrolide may have no relationship with prior use of macrolide.