In Vitro Activity of Minocycline against U.S. Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus Species Complex, Stenotrophomonas maltophilia, and Burkholderia cepacia Complex: Results from the SENTRY Antimicrobial Surveillance Program, 2014 to 2018

ABSTRACT

We evaluated the activity of minocycline and comparator agents against a large number of Stenotrophomonas maltophilia (n = 1,289), Acinetobacter baumannii-Acinetobacter calcoaceticus species complex (n = 1,081), and Burkholderia cepacia complex (n = 101) isolates collected from 2014 to 2018 from 87 U.S. medical centers spanning all 9 census divisions. The isolates were collected primarily from hospitalized patients with pneumonia (1,632 isolates; 66.0% overall), skin and skin structure infections (354 isolates; 14.3% overall), bloodstream infections (266 isolates; 10.8% overall), urinary tract infections (126 isolates; 5.1% overall), intra-abdominal infections (61 isolates; 2.5% overall), and other infections (32 isolates; 1.3% overall). Against the A. baumannii-A. calcoaceticus species complex, colistin was the most active agent, exhibiting MIC_50/90 values at ≤0.5/2 μg/ml and 92.4% susceptibility. Minocycline ranked second in activity, with MIC_50/90 values at 0.25/8 μg/ml and susceptibility at 85.7%. Activity for these two agents was reduced against extensively drug-resistant and multidrug-resistant isolates of the Acinetobacter baumannii-Acinetobacter calcoaceticus species complex. Only two agents showed high levels of activity (susceptibility, >90%) against S. maltophilia, minocycline (MIC_50/90, 0.5/2 μg/ml; 99.5% susceptible) and trimethoprim-sulfamethoxazole (MIC_50/90, ≤0.5/1 μg/ml; 94.6% susceptible). Minocycline was active against 92.8% (MIC₉₀, 4 μg/ml) of trimethoprim-sulfamethoxazole-resistant S. maltophilia isolates. Various agents exhibited susceptibility rates of nearly 90% against the B. cepacia complex isolates; these were trimethoprim-sulfamethoxazole (MIC_50/90, ≤0.5/2 μg/ml; 93.1% susceptible), ceftazidime (MIC_50/90, 2/8 μg/ml; 91.0% susceptible), meropenem (MIC_50/90, 2/8 μg/ml; 89.1% susceptible), and minocycline (MIC_50/90, 2/8 μg/ml; 88.1% susceptible). These results indicate that minocycline is among the most active agents for these three problematic potential pathogen groups when tested against U.S. isolates.