Microbiological Profile and Antimicrobial Resistance Patterns in an Intensive Care Unit: Emphasis on ESKAPE Pathogens

Background/Objectives: Antimicrobial resistance (AMR) is a major global public health threat, particularly in intensive care units (ICUs), where critically ill patients are exposed to high antimicrobial pressure. ESKAPE pathogens play a central role in healthcare-associated infections and are frequently associated with multidrug resistance. This study aimed to evaluate the microbiological profiles and antimicrobial resistance patterns of bacterial isolates from an adult ICU in a tertiary hospital in Brazil. Methods: A retrospective, observational, cross-sectional study was conducted using microbiological culture data from patients admitted during 2024 to the adult intensive care unit of a tertiary hospital in Brazil. Bacterial isolates from clinical specimens were included, and antimicrobial susceptibility testing was performed according to routine laboratory procedures. Descriptive statistics were used to summarize microorganism frequency and antimicrobial resistance rates. Results: A total of 1869 isolates were analyzed, with predominance of Gram-negative bacteria. The most frequent pathogens were Klebsiella pneumoniae (287/1869; 15.33%), Staphylococcus haemolyticus (164/1869; 8.76%), Enterococcus faecalis (144/1869; 7.69%), and Acinetobacter baumannii (135/1869; 7.21%). A high proportion of isolates belonged to the ESKAPE group. Gram-negative bacteria, particularly Klebsiella pneumoniae and Acinetobacter baumannii, showed high resistance to β-lactams, cephalosporins, carbapenems, and quinolones. Among Gram-positive organisms, resistance was high for macrolides, oxacillin, and clindamycin, while glycopeptides and linezolid remained effective. Conclusions: These findings highlight the importance of continuous microbiological surveillance and robust antimicrobial stewardship strategies. The present study adds novel local epidemiological evidence from a Brazilian ICU by integrating species-level distribution, antimicrobial-specific resistance, and resistance patterns by pharmacological class, with particular emphasis on ESKAPE pathogens.