Surveillance and correlation of antibiotic consumption and resistance of Acinetobacter baumannii complex in a tertiary care hospital in northeast China, 2003-2011

Abstract

This study investigated the changes in resistance of Acinetobacter baumannii complex and the association of carbapenem-resistant A. baumannii complex (CRAB) infection and hospital antimicrobial usage from 2003 to 2011 in a tertiary care hospital in northeast China. In vitro susceptibilities were determined by disk diffusion test and susceptibility profiles were determined using zone diameter interpretive criteria, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Data on consumption of various antimicrobial agents, expressed as defined daily dose/1,000 patients/day, were collected retrospectively from hospital pharmacy computer database. Most of 2,485 strains of A. baumannii complex were collected from respiratory samples (1,618 isolates, 65.1%), secretions and pus (465, 18.7%) over the years. The rates of antimicrobial resistance in A. baumannii complex increased significantly over the years. The rates of CRAB were between 11.3% and 59.1% over the years. The quarterly use of anti-pseudomonal carbapenems, but not other classes of antibiotics, was strongly correlated with the increase of quarterly CRAB (β = 1.661; p < 0.001). Dedicated use of anti-pseudomonal carbapenems would be an important intervention to control the increase of CRAB.

Figure 1

The secular trend of resistance to different antimicrobial agents over the years. Rapid increase of piperacillin/tazobactam resistance (p < 0.001; OR, 1.415; 95% CI, 1.358 to 1.475) and imipenem-resistance in A. baumannii complex (p < 0.001; OR, 1.289; 95% CI, 1.232 to 1.349) compared with the other antimicrobial agents resistance.