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Updated: Jul 2, 2026

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes
Published on: February 14, 2025
[Problematic bacteria]
1Departamento de Microbiologia, Hospital Universitario de Salamanca, Salamanca, Spain. jlmubel@usal.es
Introduction:
Because of the special characteristics of the critical patients, infections are one of the primary complications they suffer so that multiresistant microorganisms take on a special importance in this type of patient.
Sources:
Search in Medline using the words ICU (Intensive Care Unit), multidrug resistant, critical patient.
Development:
Glycopeptide resistant enterococci show a reduced prevalence in our setting and the VISA and hVISA are isolated sporadically. MRSA is, on the other hand, a major problem. In 2003-2005, it was already accounting for 28 %-38 % of the S. aureus isolated in the ICU, with a high percentage of fluoroquinolone (>90 %) and macrolide (>65 %) co-resistance. The extended-spectrum beta-lactamase producing enterobacteria (BLEE) also are a growing problem, worsened by their frequent co-resistance with fluoroquinolones, about 30 % according to some studies. Carbapenem resistance in A. baumannii has doubled in recent years, with values greater than 50 %, almost always associated to enzymes of the OXA group. P. aeruginosa also maintains high resistance values (25 %-30 % of resistance to imipenem, ceftazidime or ciprofloxacin), but more stable. However, high rates of multi-resistance are also observed, now about 50 % of the isolations of imipenem resistant P. aeruginosa are also to fluoroquinolones. As a whole, recent studies show that the multiresistance has multiplied in recently years by 5 in P. aeruginosa and by 7 in A. baumannii.
Conclusions:
Multiresistant bacteria infections are one of the greatest problems to combat in critical patients and control of their spreading and the development of active antimicrobials against them is one of the principal challenges at present.
Insights
Multiresistant microorganism infections pose a significant threat to critical patients. Combating these infections and developing new antimicrobials are key challenges in intensive care units (ICUs).
Area of Science:
- Infectious diseases
- Microbiology
- Critical care medicine
Context:
- Critical patients are highly susceptible to infections.
- Multiresistant microorganisms (MDROs) are a growing concern in intensive care units (ICUs).
- Specific MDROs like MRSA, BLEE, carbapenem-resistant A. baumannii, and P. aeruginosa present significant challenges.
Purpose:
- To review the prevalence and characteristics of multidrug-resistant infections in critical patients.
- To highlight the increasing resistance patterns of common pathogens in ICUs.
- To underscore the challenges in managing and treating these infections.
Summary:
- The prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) is high in ICUs, with significant co-resistance to fluoroquinolones and macrolides.
- Extended-spectrum beta-lactamase (BLEE) producing enterobacteria and carbapenem-resistant Acinetobacter baumannii are increasing, often exhibiting co-resistance to fluoroquinolones.
- Pseudomonas aeruginosa shows stable but high resistance rates to common antibiotics, with a notable increase in multidrug resistance.
Impact:
- Multiresistant bacteria infections are a major problem in critical care settings.
- Effective control of MDRO spread and development of novel antimicrobials are crucial challenges.
- Understanding resistance trends is vital for guiding treatment strategies and infection control measures.
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