Background Carbapenems are widely used as broad-spectrum antibiotics but in several cases microbiological cultures are not taken before carbapenem use, therefore hindering the down-scaling to targeted treatment.

Purpose To evaluate the increasing number of cultures requested before using carbapenems because of a pharmaceutical interventions and the results of the cultures; to describe the sensitivity of microorganisms isolated.

Material and methods Pre-Post and interventional study including adult patients using carbapenems (ertapenem, meropenem, and imipenem-cilastatin).

From June 2014, the department of pharmacy set a recommendation that a sample must be taken from the patient for microbiological culture before carbapenem was used, and the physicians have to check this recommendation to complete the electronic prescription of a carbapenem.

The record of every patient with carbapenem prescription was studied for 3 consecutive months; May, before the intervention was set up; June and July, with the intervention already in progress.

It was defined as a previous culture, 7 days before prescription.

Results Two hundred and sixty one patients (100 in May, 84 in June, 77 in July) were studied; mean age was 60.1 years, 62.1% males.

In May, 75.0% of the carbapenems prescriptions had a culture made before antibiotic use, in June, 82.1% and in July 87.3%.

During the study period, 209 culture requests were done before carbapenem prescription, 48.4% were negatives, 51.6% positives. 89.8% of the microorganisms isolated were sensitive to narrow-spectrum antibiotics, but just 21.6% of prescriptions for them were down-scaled.

Conclusion The outcome shows a clear improvement in the number of cultures requested by physicians; this allows an optimal use of antibiotics, facilitating the down-scaling strategy which avoids the appearance of antibiotic resistance.

Most of the microorganisms isolated were sensitive to antibiotics with a narrower spectrum, which gives more value to the culture at the beginning of the treatment and makes checking the down-scaling of treatment by the department of pharmacy important.

References and/or acknowledgements No conflict of interest.