Antimicrobial resistance surveillance of gram-positive cocci isolated from 12 teaching hospitals in China in 2008

Abstract

Objective To investigate antimicrobial resistance among gram-positive cocci in China in 2013. Methods Retrospective study. From June 2013 to December 2013, 1 663 consecutive and non-repetitive gram-positive cocci were collected from 15 teaching hospitals. The minimal inhibitory concentration (MIC) of antibacterial agents was determined by agar dilution method. A retrospective study was conducted on rates of resistance to antimicrobial agents. The prevalence of penicillin-resistant Streptococcus pneumoniae (PRSP) between children and adult patients and the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) between elder group and younger adult patients were compared using chi-square test. Results The prevalence of PRSP in children below 3 years old (72.9%, 51/70) was higher than adult patients (55.2%, 106/192) (χ2=6.653, P<0.05). About 94.9% (261/275) and (92.7%, 255/275) of S. pneumonia were resistant to erythromycin and clindamycin. All S. pneumoniae strains were susceptible to teicoplanin, vancomycin, linezolid, tigecycline and daptomycin. Penicillin still showed very high activity against Streptococcus spp. β-Hemolytic group. More than 60% of Streptococcus spp.β-Hemolytic group were resistant to erythromycin, clindamycin and tetracyclines. The prevalence of MRSA and methicillin-resistant coagulase-negative Staphylococci(MRCoNS) was 39.7%(229/576) and 80.6%(224/278), respectively. The MRSA prevalence ranged from 24.2% to 70.0% in different regions. About 52.6% (100/190) of Staphylococcus aureus from respiratory tract specimens, 38.5% (40/104) of Staphylococcus aureus from blood samples, and 29.7%(58/195)of Staphylococcus aureus from wound and pus were resistant to methicillin. The prevalence of MRSA in elder group (48.6%, 84/173) was higher than that in younger adult patients (35.7%, 144/403) (χ2=8.322, P<0.05). The susceptibility rates of MRSA to chloramphenicol and trimethoprim/sulfamethoxazole were 86.4% (244/228) and 94.7% (237/228), respectively. Susceptibility rates to gentamycin, erythromycin, clindamycin, tetracyclines, rifampicin and quinolones were ranged from 15.8% to 59.6%. All Staphylococci isolates were susceptible to teicoplanin, vancomycin, linezolid, daptomycin and tigecycline. All Enterococcus isolates were susceptible to daptomycin and tigecycline. All E. faecalis (158/158) and 96.4% (133/138) of E. faecium were susceptible to teicoplanin. About 98.0% (150/153) of E. faecalis and 97.1% (145/138) of E. faecium were susceptible to linezoild. About 45.8% (70/153) of E. faecalis and 60.9% (84/138) of E. faecium were resistant to gentamycin with a high concentration. The susceptibility of E. faecalis to all the antibiotics tested except chloramphenicol and tetracycline was higher than that of E. faecium. Conclusions Based on different age groups and regions, the resistance rates of Gram-positive cocci are different. Teicoplanin, vancomycin, tigecycline, daptomycin, linezolid and tedizolid showed very high activity against Gram-positive cocci.(Chin J Lab Med, 2015, 38: 373-381) Key words: Gram-positive cocci; Drug resistance, bacterial; Anti-bacterial agents; Microbial sensitivity tests; Multicenter study