The Changes in the Antibiotic Resistance of Staphylococcus aureus , Streptococcus pneumoniae , Enterococcus faecalis and Enterococcus faecium in the Clinical Isolates of a Multiprofile Hospital over 6 Years (2017–2022).

Background/Objectives: The growing resistance of bacteria to antibiotics is a serious problem in health care. The present study aims to assess the drug resistance of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis and Streptococcus pneumoniae isolated from infections in a multispecialty hospital over a 6-year period. Methods: Identification and antimicrobial susceptibility testing were performed using the VITEK®2 automated system (Biomerieux). Results and Conclusions: Based on data from the analyzed hospital, MRSA strains were the etiological factor of 18–28% of S. aureus infections. In each year from 2017 to 2022, the percentage of MSSA strains steadily exceeded the number of MRSA strains. The MRSA strains isolated show significant sensitivity to antibiotic groups other than β-lactams, such as aminoglycosides, tetracyclines, cotrimoxazole, linezolid and vancomycin. Ciprofloxacin is the antibiotic to which S. aureus displays the second-highest resistance, after methicillin. In the case of MRSA strains, almost 100% lack of sensitivity to quinolines was found. An increase in the number of infections caused by strains of the Enterococcus genus was observed. For E. faecium strains, the percentage of vancomycin-resistant strains reached as much as 41% in 2018. Among the resistant strains in E. faecalis, VREs (Vancomycin-Resistant Enterococci) slightly predominate, while GREs (Glycopeptide-Resistant Enterococci) are much more prevalent in E. faecium. The data show that the percentage of S. pneumoniae strains insensitive to ampicillin ranged from 6% to 17%. In 2017, the percentage of strains resistant to this antibiotic reached 17%, while in 2022, their share decreased to 9%. In 2021–2022, the percentage of strains resistant to erythromycin was as high as 33%. This resistance is related to the MLS (macrolides, lincosamides, streptogramines B) mechanism. An increase in S. pneumoniae resistance to 100% was observed in 2017 and 2019. In the analyzed six-year period, from 2020 (beginning of the pandemic), in some groups of antibiotics, a significant increase in consumption in DDD/100 person-days was recorded. This is most visible in the case of fluoroquinolones. The analysis carried out will increase the effectiveness of empirical therapy in the hospital and the prudent use of antibiotics to limit the selection of multidrug-resistant strains. [ABSTRACT FROM AUTHOR]