In vitro activity of aztreonam/avibactam against a global collection of Klebsiella pneumoniae collected from defined culture sources in 2016 and 2017.

ABSTRACT

OBJECTIVES: This study reports on the activity of aztreonam/avibactam (ATM-AVI) against a collection of Klebsiella pneumoniae collected in 2016 and 2017. METHODS: Non-duplicate K. pneumoniae isolates were collected from four regions (Africa/Middle East, n = 785; Asia-Pacific, n = 1433; Europe, n = 4236; Latin America, n = 1499) and five culture sources (blood, n = 902; intra-abdominal, n = 992; urinary tract, n = 2148; skin and skin structure, n = 1409; lower respiratory tract, n = 2502). MICs were determined at a central laboratory using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology. Susceptibility was determined using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. RESULTS: For all culture sources, against all K. pneumoniae, the highest rates of susceptibility were seen for amikacin (>84%), ceftazidime/avibactam (>94%), colistin (>92%) and meropenem (>83%), and >99.9% of isolates were inhibited at an ATM-AVI MIC of ≤4 mg/L. Among meropenem-resistant (MEM-R, n = 583) and meropenem-resistant metallo-ß-lactamase-negative (MEM-R-MBLN; n = 469) isolates, susceptibility was highest to ceftazidime/avibactam (79.9% and 99.4%, respectively) and colistin (67.2% and 62.7%, respectively). All MEM-R-MBLN isolates from blood, intra-abdominal, urinary tract and skin and skin structure sources, and all but one isolate from respiratory sources, were inhibited at an ATM-AVI MIC of ≤2 mg/L. Against the meropenem-resistant metallo-ß-lactamase positive (MEM-R-MBLP; n = 114) isolates, susceptibility to colistin was between 75.0% (urinary tract isolates) and 93.3% (lower respiratory tract isolates). All MEM-R-MBLP isolates were inhibited at an ATM-AVI MIC of ≤0.5 mg/L. CONCLUSIONS: ATM-AVI is active against K. pneumoniae isolates from a range of culture sources across Africa/Middle East, Asia-Pacific, Europe and Latin America. ATM-AVI also has activity against MEM-R-MBLN and MEM-R-MBLP isolates.