The genetic features of drug resistance to group A streptococcus and macrolides antibiotics among pediatric patients in Beijing 2012 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the genetic features of drug resistance to group A streptococcus(GAS) and macrolides antibiotics among pediatric patients in Beijing 2012.</p><p><b>METHODS</b>A total of 199 strains of GAS were collected from 36 hospitals in Beijing between May and July, 2012. All strains were isolated from oropharyngeal swabs. The minimum inhibitory concentrations (MICs) of ten antibiotics (penicillin, ampicillin, erythromycin, clindamycin, tetracycline, levofloxacin, tigecycline, vancomycin, linezolid and streptogramin) were detected by VITEK-2 compact with GPS-67 test kit. The genes encoding macrolides resistance (ermA, ermB and mefA ) were amplified and tested by PCR. The macrolides resistant phenotype of group A streptococcus was detected by double disc test (D-test).</p><p><b>RESULTS</b>Among 199 strains of GAS collected in this study, 101(50.8%) were from suburbs and the other 98(49.2%) were from urban areas. 111(55.8%) strains were collected from scarlet fever patients while the other 88(44.2%) were from oropharyngeal infection cases. All the strains were sensitive to penicillin and ampicillin, and the percentage of resistance to erythromycin, clindamycin and tetracycline were 96.5% (192/199), 95.5% (190/199) and 92.0% (183/199), respectively. All strains were susceptible to levofloxacin, tigecycline, vancomycin, linezolid and streptogramin. The rates of resistance to erythromycin, clindamycin and tetracycline were different in different districts, however, the difference in it between ages and clinical diagnosis did not show statistical significance (P > 0.05) . The detected rate of drug resistance gene ermB was 98.5% (196/199). The gene ermA was only detected out in 5 strains and the gene mefA was not detected out. 199 strains showed A macrolides resistant phenotype cMLS, while the phenotype iMLS was not found in this study.</p><p><b>CONCLUSION</b>This study demonstrates the high level of clindamycin resistance in group A streptococcus collected from children in Beijing, 2012. The macrolides resistance of group A streptococcus was highly prevalent in Beijing, and the dominant phenotype was cMLS mediated by gene ermB.</p>

Characteristics and related factors related to the resistance on antibiotics among group A streptococcus strains isolated from children in Beijing, during May and July 2011 / 中华流行病学杂志

Objective To analyze the characteristics of antibiotic resistance on group A streptococcus isolated from pediatrics in Beijing in 2011,to provide reference for clinical drug administration.Methods Strains of group A streptococcus were collected from the Departments of Pediatrics in 36 hospitals at different Districts of Beijing,from May to July 2011.Minimal inhibitory concentrations (MIC) with ten antibiotics of these isolates were tested by VITEK 2 Compact method.All the Susceptibility rate (S％),Intermediate rate (I％) and Resistance rate (R％) were calculated according to their MIC values.The macrolides resistant phenotype of group A streptococcus was detected by D-test.Results A total of 633 (19.1％) group A streptococcus strains were cultured from 3315 throat swabs.All the isolates were susceptible to penicillin,ampicillin,streptogramin,linezolid,tigecycline,vancomycin,while 96.5％ (611/633) of the isolates were susceptible to levofloxacin.A total of the 96.1％ (608/633) isolates exhibited resistance to erythromycin.The resistance rates to clindamycin and tetracycline were 79.3％ (502/633)and 93.7％ (593/633),respectively.A total of 9 different resistant patterns were observed,with the dominant patterns as:concomitant resistance to erythromycin,clindamycin and tetracycline (72.7％,460/633),followed by combined resistance to erythromycin and tetracycline (18.0％,114/633).The most commonly seen macrolide resistant phenotype was cMLS type (83.2％).In total,97 strains belonged to iMLS type and 5 strains to M type.Data through multivariate logistic regression analysis showed that factors as occupation and samples being collected from the sub-unban areas etc.were significantly associated with the resistance rates to tetracycline and the odds ratio (95％CI) as 2.43 (1.16-5.09) and 2.35 (1.47-3.73).Isolates collected from the sub-unban areas were significantly associated with resistance rates to clindamycin,with the odds ratio (95％CI) being 0.48(0.25-0.92).Conclusion All the isolates acquired from the Pediatrics Departments in Beijing were susceptible to penicillin and ampicillin.The high resistance rates of erythromycin,clindamycin and tetracycline resistance to group A streptococcus were observed,with the major resistant phenotype as cMLS.Factors as occupation and the collection site of samples were significantly associated with the resistance rates to tetracycline while the sites of sample collection were significantly associated with the resistance rates to clindamycin.