This study, based on the SMART global surveillance program, retrospectively analyzed the trends in in vitro susceptibility of clinical isolates of Pseudomonas aeruginosa to ceftolozane/tazobactam in Latin America from 2016 to 2024, revealing an overall stable susceptibility rate of 86.3%, particularly higher among pediatric patients. The study also highlights a significant increase in susceptibility among urinary isolates and a sharp rise in resistance observed at a hospital in Guatemala, indicating the necessity for ongoing monitoring.
Literature Overview
The article 'Trends in Pseudomonas aeruginosa In Vitro Susceptibility to Ceftolozane/Tazobactam in Latin America: SMART Surveillance Program, 2016–2024' published in the journal Antibiotics, reviews and summarizes the changing trends in in vitro antimicrobial activity of Pseudomonas aeruginosa against ceftolozane/tazobactam in the Latin American region. It emphasizes the overall high susceptibility to this drug in Latin America, while also highlighting warning signals of increasing local resistance.
Background Knowledge
Pseudomonas aeruginosa is a significant pathogen causing hospital-acquired infections, particularly common in immunocompromised patients. Its resistance mechanisms are complex, including low membrane permeability, β-lactamase expression, and overexpression of efflux pumps. Ceftolozane/tazobactam is an important drug for treating multidrug-resistant Pseudomonas aeruginosa infections; however, metallo-β-lactamase (MBL)-positive strains exhibit intrinsic resistance. Latin America is a region with high resistance rates among Gram-negative bacteria, and this study leverages the SMART surveillance program to analyze the long-term antimicrobial activity of ceftolozane/tazobactam in the region, providing data support for clinical treatment decisions.
Research Methods and Experiments
The SMART surveillance program collected a total of 10,188 isolates of Pseudomonas aeruginosa from 57 clinical centers across 12 Latin American countries between 2016 and 2024. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, interpreted according to the 2025 CLSI M100 guidelines. Fourteen centers (from 6 countries) participated continuously over 9 years, providing 4,565 isolates for stability analysis. Stratified analyses were also conducted based on infection source (blood, abdomen, respiratory tract, urine), age groups (adult vs. pediatric), and country.
Key Conclusions and Perspectives
Research Significance and Prospects
This study confirms the sustained antimicrobial activity of ceftolozane/tazobactam against Pseudomonas aeruginosa in Latin America, particularly notable in pediatric patients and urinary tract infections. However, the sharp increase in resistance at a hospital in Guatemala highlights the need for enhanced regional antimicrobial surveillance. Future research should focus on the spread of resistance mechanisms (e.g., MBLs) and explore combination therapy strategies to counteract the potential dissemination of DTR strains.
Conclusion
By analyzing long-term data from the SMART surveillance program, this study assessed the in vitro antimicrobial activity trends of ceftolozane/tazobactam against Pseudomonas aeruginosa in Latin America. The results indicate that the drug maintains high susceptibility across the region, particularly showing increasing susceptibility rates in pediatric and urinary isolates over the years, suggesting its importance in clinical treatment. However, the sharp rise in resistance at a hospital in Guatemala may be linked to inappropriate antibiotic stewardship or the spread of MBL genes. The study emphasizes that, although the overall trend remains stable, continuous monitoring of local resistance changes is essential to optimize empirical treatment strategies and prevent the spread of resistance.
