Antibiotic dispensing during first year of COVID-19 pandemic in Brazilian public hospitals.

Aim: To evaluate the impact of the first year of the COVID-19 pandemic on antibiotic dispensation in three Brazilian hospitals. Methods: Stock movement was accessed from pharmacy databases and microbiological reports from 2018 to 2021. Results: Reduced antibiotic dispensation occurred during 2020 in all hospitals. The most significant reduction was in April at Hospital Doutor Jayme dos Santos Neves (∼58%), and in May at Hospital Doutor Roberto Arnizaut Silvares (∼66%) and Hospital Doutor Dório Silva (∼29%). However, azithromycin dispensation increased in all hospitals in 2020. Macrolide-resistant bacterial isolates rose from 66.6% in 2019 to 77.1% in 2020 and 88.3% in 2021. Conclusion: Despite reduced antibiotic dispensation, the increase in azithromycin consumption in 2020 highlights the urgency to monitor macrolide resistance after the pandemic and improve stewardship activities.

Drug-induced tolerance: the effects of antibiotic pre-exposure in Stenotrophomonas maltophilia.

Aim: To investigate if the prior use of nontargeted antibiotics induces cross-tolerance in Stenotrophomonas maltophilia. Methods: Antibiotic induction was performed to evaluate daptomycin and vancomycin as possible tolerance-inducing drugs measured by minimum bactericidal concentration/minimum inhibitory concentration (MIC) ratio, adapted disk-diffusion tests and time-kill curves. Results: After antibiotic exposure, three potentially tolerant strains were isolated, maintaining the same MIC value of levofloxacin, with minimum bactericidal concentration/MIC ratio slightly higher than the parental. In the adapted disk-diffusion test, one strain (D25) showed high tolerance level for levofloxacin, ceftazidime and ticarcillin-clavulanate. In time-kill activity of levofloxacin, D25 presented a subpopulation of persisters with survival rate higher (1.6-fold) than the parental. Conclusion: Previous exposure of S. maltophilia to daptomycin can induce cross-tolerance to ceftazidime and ticarcillin-clavulanate and cross-persistence to levofloxacin.