Analysis Of Antimicrobial Resistance And Drug Resistant Genes Of Streptococcus Pneumoniae Isolated From Children With Clinical Acute Respiratory Infection In Chongqing Area

Objective To investigate the resistance of Streptococcus pneumoniae in children with acute respiratory infections in Chongqing area. Exploring the resistant mechanism of penicillin,macrolides, tetracyclines of Streptococcus pneumoniae isolated from children with acute respiratory infection in Chongqing area.Methods The respiratory tract specimens (sputum, bronchoalveolar lavage fluid) were collected from January to March, September to November isolation in 2014 in Children’s hospital of Chongqing Medical University, and Streptococcus pneumonia were isolated and cultured, finally got the drug sensitivity test results. The bacterial DNA were extracted using boiling method, the products of PCR amplification of drug resistance related genes TEM, ermB, mefA, mefE and tetM, were observed by agarose gel electrophoresis.Results A total of 241 strains of Streptococcus pneumonia were isolated, erythromycin had the highest resistance rate, reaching 97.1%, followed by clindamycin 89.63%, tetracycline 91.7%; No drug-resistant strains of vancomycin were detected; Linezolid, moxifloxacin, levofloxacin, chloramphenicol, telithromycin were more sensitive, more than 90%; meropenem, cefepime, Penicillin were not sensitive, respectively 81.74%,67.22%,47.3%; The main patterns of resistance was meropenem and erythromycin and clindamycin and cotrimoxazole and tetracycline (21.16%); Compared with penicillin-susceptible Streptococcus pneumoniae (PSSP) and penicillin-nonsusceptible Streptococcus pneumoniae (PNSSP), the nonsusceptible rates of erythromycin, amoxicillin, cefepime, meropenem, cotrimoxazole, clindamycin, cefotaxime had statistically significant difference (P<0.05). Three of the five drug resistance genes TEM, ermB, tetM detection rates were high, respectively 95.02%,96.68%, 91.29%; all the 8 penicillin resistant Streptococcus pneumoniae strains carried TEM gene; 234 SP strains were resistant to erythromycin, among which 120 strains (51.28%)were carrying ermB gene alone,2 strains(0.85%) carried mefA/E alone,106 strains (45.30%) carried both ermB and mefA/E, and 6 strains (2.56%) carried neither ermB nor mefA/E; a total number of 221 SP strains were resistant to tetracycline, and 205 isolates (92.76%) carried tetM.Most of the PSSPs(92.91%) were positive for TEM gene,all the 6 erythromycin sensitive strains were positive for ermB gene,9 in 12(75%) of the tetracycline sensitive strains were positive for tetM gene.Conclusion Erythromycin, tetracycline, clindamycin should not be used in children with acute respiratory infections because of their higher resistance rates in Chongqing; and penicillin and cephalosporins should be carefully used in empirical treatment due to their high non-sensitive rates; The drug resistance to macrolide antibiotics is mainly composed of ermB alone or ermB and mefA/E mediated by Streptococcus pneumoniae in children with acute respiratory tract infection in Chongqing area, Tetracycline resistance of SP mediated by tetM. The relationship between TEM gene positive and penicillin resistance is not clear, and need to be further studied. The clinical medication should pay more attention to the bacterial culture, and rational use of antibiotics should be based on susceptibility test results, so as to prevent the spread and prevalence of drug resistent strains..