title: Antimicrobial resistance trends among 5608 clinical Gram-positive isolates in China: results from the Gram-Positive Cocci Resistance Surveillance program (2005-2010).
abstract: A total of 5608 clinical isolates of Gram-positive bacteria were collected from 12 teaching hospitals across China from 2005 to 2010. The minimum inhibitory concentrations (MICs) of 19 antimicrobial agents were determined by the agar dilution method at the central laboratory. Overall, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRSCoN) were 46.8% and 81.5%, respectively. Isolates from inpatients exhibited a higher rate of MRSA than that from outpatients (52.3% versus 26.2%, P < 0.001). The prevalence of MRSA in respiratory infections (67.5%) was higher than in other sources of infections (P < 0.001). A shift in vancomycin MICs from <0.5 to 1.0 μg/mL was observed during the 6-year period. In 2005, 70.5% of S. aureus isolates were inhibited at the vancomycin MIC of 0.5 μg/mL, while in 2010, 89% of the isolates were inhibited at the vancomycin MIC of 1 μg/mL. With the use of penicillin oral breakpoints, penicillin-resistant Streptococcus pneumoniae (PRSP) increased from 28.6% in 2005 to 59.5% in 2010 and varied among different age groups, with an average rate of 70.6% for children under 5 years old. Importantly, an obvious penicillin MIC right shift was observed from 0.032 to 4 μg/mL during the study period. Serotyping for the isolates from 2005 and 2010 indicated that the high rate of PRSP could be due to the increased prevalence of serogroup 19. The prevalence of vancomycin-resistant enterococci (VRE) increased from 0 in 2005 to 4.9% in 2010. Of the 27 VRE isolates, vanA gene was the most prevalent gene. During the study period, 97.9-100% of different species tested were susceptible to teicoplanin. Linezolid and tigecycline showed potent activities, and no resistant isolate was identified. In conclusion, although the prevalence of MRSA and MRSCoN remained stable over the 6 years, a sharp increase in the prevalence of PRSP was identified. In addition, MIC shifts, including the MICs of penicillin against S. pneumoniae and vancomycin against S. aureus, were observed. Continuous surveillance is warranted to evaluate the resistance trend of clinically important Gram-positive organisms in the future.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China.
authors.forename: Chunjiang
authors.initials: C
authors.lastname: Zhao
authors.forename: Hongli
authors.initials: H
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Yudong
authors.initials: Y
authors.lastname: Liu
authors.forename: Bijie
authors.initials: B
authors.lastname: Hu
authors.forename: Yunsong
authors.initials: Y
authors.lastname: Yu
authors.forename: Ziyong
authors.initials: Z
authors.lastname: Sun
authors.forename: Yunzhuo
authors.initials: Y
authors.lastname: Chu
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Kang
authors.initials: K
authors.lastname: Liao
authors.forename: Jin'e
authors.initials: J
authors.lastname: Lei
authors.forename: Zhidong
authors.initials: Z
authors.lastname: Hu
authors.forename: Liyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Zhang
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Xu
authors.forename: Zhanwei
authors.initials: Z
authors.lastname: Wang
authors.forename: Minjun
authors.initials: M
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D062486:Public Health Surveillance
chemical_list: D000900:Anti-Bacterial Agents