Multidrug-Resistant Bacterial Strains in Northern Mexico: Clinical Impact and Vitek 2-Based Characterization

Antibiotic resistance remains a major public health concern, particularly in regions with high rates of hospital- and community-acquired infections. This study aimed to quantify multidrug-resistant (MDR) bacterial strains in northern Mexico and to identify the most prevalent resistance phenotypes, the antibiotic classes with the highest resistance and susceptibility rates, the predominant MDR species, and the specimen types yielding the greatest number of isolates. Clinically relevant strains were collected from patients with confirmed infections. Microorganism identification and antimicrobial susceptibility test-ing were performed using the Vitek 2 Compact system (bioMérieux), and the results were analyzed descriptively. Of the 1544 strains analyzed, 761 (49.29%) exhibited multidrug resistance. Escherichia coli was the most frequently isolated MDR species, followed by Pseudomonas aeruginosa. Acinetobacter baumannii showed the highest resistance rate, with 95.55% of its strains classified as MDR, whereas P. aeruginosa had the lowest MDR proportion at 30.73%. These findings underscore the urgent need for rational antibiotic use and the development of new therapeutic agents, particularly those targeting Gram-negative bacilli, to mitigate the growing threat of antimicrobial resistance in this region.