ANTIMICROBIAL SUSCEPTIBILITY ANALYSIS OF ESCHERICHIA COLI, STREPTOCOCCUS SPP. AND KLEBSIELLA SPP.: RETROSPECTIVE DATA FROM A MULTIDISCIPLINARY HOSPITAL IN BUCHAREST (2021 - 2024)

Antimicrobial resistance is one of the most critical challenges in modern medical practice, limiting the effectiveness of treatments and increasing the risk of complications.In this context, constant monitoring of bacterial susceptibility profile s becomes necessary for guiding empiric therapy and optimising antibiotic stewardship strategies.This retrospective observational study was conducted between 2021 and 2024 at the Fundeni Clinical Institute.Escherichia coli, Escherichia coli ESBL-positive, Streptococcus spp.and Klebsiella spp.strains isolated from invasive biological products were analysed.Susceptibility to antibiotics was assessed according to EUCAST standards, and the overall level of resistance was quantified using the mean antibiotic resistance index (MARI).E. coli showed a favourable susceptibility profile, whereas ESBL-positive strains showed a progressive increase in MARI values.Klebsiella pneumoniae had the highest MARI levels, especially in blood and urine cultures.In contrast, Streptococcus spp.maintained a low level of resistance in all sample types analysed.The results support the need for continuous adjustment of therapeutic protocols according to local resistance trends and emphasise the importance of close collaboration between the microbiology laboratory, prescribing physicians, infectious disease physicians and clinical pharmacists for effective infection control. RezumatRezistena antimicrobian reprezint una dintre cele mai importante provocri ale practicii medicale moderne, limitnd eficacitatea tratamentelor i crescnd riscul de complicaii.n acest context, monitorizarea constant a profilurilor de susceptibilitate bacterian devine esenial pentru ghidarea terapiei empirice i optimizarea strategiilor de utilizare responsabil a antibioticelor.Acest studiu observaional retrospectiv a fost desfurat n perioada 2021 -2024, n cadrul Institutului Clinic Fundeni.Au fost analizate tulpini de Escherichia coli, Escherichia coli productoare de ESBL, Streptococcus spp.i Klebsiella spp., izolate din produse biologice invazive.Susceptibilitatea la antibiotice a fost evaluat conform standardelor EUCAST, iar nivelul general de rezisten a fost cuantificat prin intermediul indicelui mediu de rezisten la antibiotice (MARI).E. coli a prezentat un profil favorabil de susceptibilitate, n timp ce tulpinile ESBL-pozitive au nregistrat o cretere progresiv a valorilor MARI.Klebsiella pneumoniae a evideniat cele mai ridicate niveluri ale indicelui MARI, n special n hemoculturi i uroculturi.n contrast, Streptococcus spp. a meninut un nivel sczut de rezisten n toate tipurile de probe analizate.Rezultatele obinute susin necesitatea ajustrii continue a protocoalelor terapeutice n funcie de tendinele locale de rezisten i subliniaz importana colaborrii strnse ntre laboratorul de microbiologie, medicii prescriptori, medicii infecioniti i farmacitii clinicieni, pentru un control eficient al infeciilor.