Susceptibilities of Gram-negative bacilli from hospital- and community-acquired intra-abdominal and urinary tract infections: a 2016–2017 update of the Chinese SMART study

Objectives: To update the epidemiology and susceptibility of hospital-acquired (HA) and community-acquired (CA), as well as intensive care unit (ICU) vs non-ICU-derived intra-abdominal infection (IAI) and urinary tract infection (UTI) pathogens in Chinese hospitals. Methods: A total of 2,546 Gram-negative isolates from IAIs and 1,947 isolates from UTIs collected in 16 hospitals and 7 regions of China from 2016 to 2017 were analyzed. Results: E. coli and K. pneumoniae were the most common pathogens identified in HA (40.7%, 21.9%) and CA (49.2%, 21.3%) IAIs and in HA (59.0%, 17.3%) and CA (64.3%, 12.7%) UTIs, respectively. The overall rates of extended-spectrum β-lactamase (ESBL)-positive strains were 48.2% for E. coli and 26.4% for K. pneumoniae. The rates of ESBL-positive E. coli and K. pneumoniae strains were significantly higher in HA than in CA IAIs (51.7% vs 42.4%, P=0.016 and 22.0% vs 20.6%, P<0.001). IAI E. coli ESBL-producing isolates were most susceptible to IPM (97.2%) and AMK (93.9%), and UTI-associated E. coli ESBL-producers were 94.74% susceptible to amikacin (AMK), 97.02% to imipenem (IPM), and 91.4% to ertapenem (ETP). IAI K. pneumoniae ESBL-producing isolates were most susceptible to AMK (84.43%) and IPM (82.79%), and UTI-associated K. pneumoniae ESBL-producers were 88.39% susceptible to AMK, 87.5% to IPM, and 82.14% to ETP. Overall, percentages of susceptible strains to ETP, IPM, AMK, and Piperacillin-Tazobactam (TZP) were in the range of 82.0% to 96.4%, to 5 cephalosporins in the range of 31.4%-69.6% and to 2 fluoroquinolones in the range of 37.8%-45.5% for E. coli and 65.5%-90.7%, 37.7%-75.3%, and 43.9%-73.2% for K. pneumoniae, respectively. Conclusion: E. coli and K. pneumoniae continued to be the main pathogens in Chinese UTIs and IAIs with high ESBL-positive rates between 2016 and 2017. Carbapenem- or amikacin-based therapies were the most effective to combat IAI and UTI pathogens.