[Antibiotic consumption and bacterial sensitivity in a teaching hospital: A 5-year study]

To reduce risks of antibiotic resistance, governmental and learned societies decreed the optimal use of antibiotics. The relation between antibiotic consumption and bacterial resistance increase has been clearly demonstrated over the last several years. Antibiotic consumption data and bacterial sensitivity data are regularly published, but very few publications have searched for a correlation between these two variables. This study focused on antibiotic use and consumption as well as bacterial sensitivity to these antibiotics.

The main objective was to describe the changes in antibiotic consumption and bacterial sensitivity in a mother-child teaching hospital. The secondary objectives were to explore whether antibiotic use and bacterial sensitivity were correlated and to comment on the usefulness of these data for clinicians.

This was a 5-year retrospective, descriptive, cross-sectional study. All samples from usually sterile biologic liquids of hospitalized pediatric patients were included in the study. The samples from outpatient clinics were excluded. All types of bacteria identified in more than 30 isolates were included in the study. The antibiotics usually used to treat these bacteria were included. To assess antibiotic consumption, we calculated the number of days of therapy per 1000 patient-days for hospitalized pediatric patients and we calculated the Pearson correlation coefficient between antibiotic consumption and sensitivity rates to these antibiotics. Two scenarios were explored: one with correlation by year and one with the next year for bacterial sensitivity.

During the study period (2010-2011 to 2014-2015), overall antibiotics consumption remained relatively stable. Concerning bacterial sensitivity, we noted important changes (sensitivity rates increased for 12 antibiotic-bacteria pairs, remained stable for five, and decreased for 15). We found three significant correlations for the first scenario: Pseudomonas aeruginos-ceftazidime (P=0.01), P. aeruginosa-ciprofloxacin and fluoroquinolone consumption (P=0.02), Enterococcus sp-ampicillin and penicillin consumption (P=0.04). For the second scenario, we found only two significant correlations: coagulase-negative Staphylococcus-oxacilline and penicillin consumption (P=0.02), P. aeruginosa/piperacillin (P=0.04).

This exploratory study allowed us to describe antibiotic consumption and bacterial sensitivity progression. To our knowledge, this is the first study exploring the correlation between antibiotic consumption and the bacterial sensitivity rate in pediatrics in Canada. It remains very difficult to show this correlation between these two variables because of the multiple sources of bacterial resistance. These data are particularly useful for the antimicrobial stewardship programs and for clinicians.