Background Evidence exists that treatment with antimicrobial agents leads to the development of resistance to the same compound or cross-resistance to other compounds.
Purpose To detect correlations between the consumption of antimicrobial agents and bacterial resistance, in monthly and quarterly checks.
Materials and methods We studied 252 endotracheal intubated patients hospitalised in the Intensive Care Unit (ICU) between 1.03.2012–30.06.2013. From the tracheal secretion samples we isolated 230 strains of Klebsiella and 115 of Pseudomonas, which we tested for antibiotic susceptibility. We performed correlations between aggregated monthly and quarterly resistances with consumption of antimicrobial agents in the ICU ward, obtained from hospital’s pharmacy records. Significant correlations were verified by regression.
Results We detected a strong correlation between the consumption of ciprofloxacin and meropenem with resistance of Pseudomonas (r = 0.8565, p = 0.0066) and between consumption of ampicillin with resistance to ciprofloxacin (r = 0.6570, p = 0.0281).
The evolution of a global resistance index (Mean Antibiotic Resistance MAR) correlated with the consumption of piperacillin with tazobactam (r = 0.7852, p = 0.0643).
For Klebsiella there was an inverse correlation between ciprofloxacin consumption and gentamicin resistance (r = -0.6311, p = 0.0504) and piperacillin with tazobactam consumption and tigecycline resistance (r = 0.8155, p = 0.0925).
The evolution of a global Klebsiella resistance index (MAR) correlated with the consumption of piperacillin with tazobactam (r = 0.7768, p = 0.0692) and strong consumption of moxifloxacin (r = 0.9734, p = 0.0011).
Quarterly resistance index of Klebsiella correlated strongly with that of Pseudomonas (r = 0.9690, p = 0.0014), but with significantly different values (Student’s t test, Cohen’s d = 1.802, r = -0.669, p = 0.011). Correlation is maintained for monthly resistance (r = 4552, p = 0.0764).
Conclusions The existence of these correlations makes it necessary to monitor anti-bacterial treatment in ICU and bacterial resistance. We need to develop treatment policies for periodical changing of the set of antimicrobial drugs used.
No conflict of interest.