Correlation between carbapenem consumption and antimicrobial resistance rates of Acinetobacter baumannii in a university-affiliated hospital in China.

To investigate the correlation between carbapenem consumption and rates of antimicrobial resistance in Acinetobacter baumannii, carbapenem consumption was expressed as defined daily dose based on the World Health Organization (WHO) anatomical therapeutic chemical classification index. Clinical isolates from 2001-2009 were collected and analyzed using WHONET 5.4 software. Results show that the consumption of imipenem/cilastatin, meropenem, and total carbapenem is significantly correlated with imipenem resistance in A baumannii (r = 0.818, P = .007; r = 0.817, P = .007; r = 0.827, P = .006). Furthermore, total carbapenem consumption is significantly correlated with meropenem resistance in A baumannii (r = 0.900, P = .037). In addition, consumption of imipenem/cilastatin, meropenem, and total carbapenem is associated with A baumannii resistance to piperacillin-tazobactam, ceftazidime, cefepime, amikacin, and levofloxacin. These drugs are mainly β-lactams, aminoglycosides, and fluoroquinolones. The imipenem and meropenem resistance rates are significantly correlated with resistance rates to numerous antimicrobial drugs (eg, β-lactams, aminoglycosides, and fluoroquinolones) in A baumannii. Therefore, increased consumption of carbapenem may contribute to the development of resistance in A baumannii to imipenem, meropenem, and other antimicrobial drugs. Cross-resistance possibly occurs among imipenem/cilastatin and meropenem, as well as with β-lactams, aminoglycosides, and fluoroquinolones.