Non-adherence to guidelines: an avoidable cause of failure of empirical antimicrobial therapy in the presence of difficult-to-treat bacteria

To identify the risk factors of ventilator-associated pneumonia (VAP) due to difficult-to-treat (DTT) bacteria (i.e., Pseudomonas aeruginosa, Acinetobacter baumannii and oxacillin-resistant Staphylococcus aureus), and to assess the rate and the causes of inappropriateness of empirical antimicrobial therapy. In an intensive care unit of a university hospital, patients with VAP were empirically treated with antibiotics without activity against DTT bacteria if the patients had no prior hospitalization or prior administration of antibiotics, according to local guidelines. Overall, the empirical antimicrobial therapy was appropriate in 190 (87%) out of 218 patients with VAP. Fifty (23%) patients developed problems due to DTT bacteria. The risk factors for VAP due to DTT bacteria were shock state, prior antimicrobial therapy, prior stay in long-term care facilities and late-onset VAP. Empirical antimicrobial therapy was inappropriate in 20 (40%) patients with VAP due to DTT bacteria and 8 (5%) patients with VAP due to non-DTT (P = 0.001). Guidelines violations (nine patients), bacteria not included in antibiotic spectrum (eight patients) and bacterial resistance (three patients) were the causes of inappropriateness in case of DTT bacteria. Despite the abundant information for the treatment of VAP and the establishment of guidelines, too many patients with DTT bacteria received inappropriate antimicrobial therapy. Since 45% of the cases are related to non-adherence to the local protocol, there is room for improvement by implementing educational programs. Also, since DTT bacteria are found in 23% of late-onset VAP, empirical antibiotic treatment should be directed against these pathogens.