Immediate and later impacts of antimicrobial consumption on carbapenem-resistant Acinetobacter spp., Pseudomonas aeruginosa, and Klebsiella spp. in a teaching hospital in Brazil: a 10-year trend study.

To evaluate trends and the immediate and late impact of antimicrobial consumption on carbapenem-resistant Acinetobacter spp. (CRAs), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Klebsiella spp. (CRKs) over a 10-year period. An ecological study was conducted at the teaching hospital in São Paulo, Brazil, from 2007 to 2016. Consumption and resistance data were collected from the supply sector and central laboratory of the institution, respectively. Associations between consumption and resistance were analyzed in the same year, 1 year later, and 2 years later by linear regression of mixed effects. A total of 22,041 isolates were analyzed. Among these, 9988 corresponded to the gram-negatives in this study [3682 (36.9%) were Klebsiella spp., 3169 (31.7%) were P. aeruginosa, and 3137 (31.4%) were Acinetobacter spp.]. An increasing trend of consumption was observed, except for fourth-generation cephalosporins. Carbapenems were the most used antimicrobial class; CRKs presented a substantial increase over this period (from 1.4 to 67.0%; p = 0.001). Increased consumption of third-generation cephalosporins reduced CRAs [- 2.43%, 95% confidence interval (CI), - 3.30 to - 1.57; p < 0.001] and increased CRPA [26.67%, 95% CI, 2.99 to 50.35; p = 0.034] in the same year. Increased consumption of β-lactam/β-lactamase inhibitors increased CRKs with a 1-year delay [5.13%, 95% CI, 2.40 to 7.86; p = 0.001]. Our study demonstrated high antimicrobial consumption and growing carbapenem-resistance rates among gram-negative bacteria, especially Klebsiella spp., and the immediate and later effects of consumption of multiple antimicrobials on carbapenem resistance.