Results from the Survey of Antibiotic Resistance (SOAR) 2009-11 and 2013-14 in China.

OBJECTIVES: To compare antibiotic susceptibility of community-acquired respiratory bacteria in China during 2009-11 and 2013-14.

METHODS: Susceptibility was determined by Etest(®) (bioMérieux) or disc diffusion according to CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints, except for azithromycin where Etest(®) breakpoints (in CO2 incubation) were used in place of standard CLSI breakpoints. Statistical significance of differences in susceptibility across time periods was evaluated using Fisher's exact test.

RESULTS: During 2009-11, 434 Streptococcus pneumoniae, 307 Haemophilus influenzae and 140 Moraxella catarrhalis were collected from eight centres and during 2013-14, 208 S. pneumoniae, 185 H. influenzae and 80 M. catarrhalis were collected from five centres. Penicillin-non-susceptible isolates remained stable at ∼66% over both time periods but susceptibility decreased significantly for amoxicillin/clavulanic acid (or amoxicillin) and cefaclor. For H. influenzae, the proportion of β-lactamase-positive isolates and β-lactamase-negative ampicillin-resistant strains (CLSI definition) was higher in 2013-14 (25.4% and 7.0%, respectively) than in 2009-11 (16.3% and 3.6%, respectively), with decreased ampicillin and cephalosporin susceptibility. By 2009-11 and 2013-14, only amoxicillin/clavulanic acid (amoxicillin), levofloxacin, penicillin (intravenously) and chloramphenicol inhibited >70% of S. pneumoniae. During 2013-14, M. catarrhalis showed increasing resistance, with cefaclor and levofloxacin susceptibility decreasing significantly. However, amoxicillin/clavulanic acid, cefuroxime and levofloxacin continued to inhibit >90% of isolates.

CONCLUSIONS: On the whole, antimicrobial susceptibility decreased in China between 2009-11 and 2013-14. In 2013-14, amoxicillin/clavulanic acid, levofloxacin and chloramphenicol were the most active antibacterial agents tested against community-acquired respiratory pathogens when assessed by CLSI, EUCAST or PK/PD breakpoints. Resistance to other antibacterials in China was generally high. Our data demonstrate the need to harmonize breakpoints for these pathogens.