[Microbiology and antibiotic-therapy in patients admitted to a Community Hospital according to days of hospitalization, 2022-2023].

Abstract

Introduction: Microorganisms isolated from clinical samples in hospitalized patients vary in species and antibiotic sensitivity, depending on whether they are community or healthcare-associated infections. In a hospital in the Buenos Aires Metropolitan Area, bacterial isolates and their antibiotic resistance were related to the length of hospitalization, as a guide to adjust antibiotic therapy.

Materials and methods: Microbiological isolates, antibiogram results, and antibiotic treatment of hospitalized patients were recorded weekly between 1/1/2022 and 12/31/2023. Four groups were assigned according to time since hospitalization: G1 (<3 days), G2 (3-7 days), G3 (7-14 days), and G4 (≥14 days).

Results: In the first week of hospitalization, the main microorganism isolated, from community-acquired infection, was Escherichia coli (132 isolates), with high levels of resistance to quinolones, followed by Klebsiella pneumoniae (82 isolates) and Staphylococcus aureus (64 isolates). Between 11/10/23 and 8/12/23, an outbreak of K. pneumoniae carbapenemase MBL was detected in biliodigestive and urological surgery, and it was controlled. Of the antibiotics used: ciprofloxacin went from second in use in G1 and first in G2, to third and fifth in G4. Indications for amoxicillin/sulbactam decreased from G3. Carbapenems and colistin increased from G3. Piperacillin/tazobactam and vancomycin were widely used in all periods. This simple weekly control allowed us to know the microbiology in the hospital, its antibiotic sensitivity patterns, detect outbreaks, and adjust the rational use of antibiotics, especially empirical, notably in the abuse of ciprofloxacin in urinary or abdominal foci; and compare the isolations and therapeutic behaviors with national and international patterns.