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Resistance patterns among nosocomial pathogens: trends over the past few years
1Department of Pathology, University of Iowa College of Medicine, Iowa City, Iowa, USA.
Abstract:
Multiple surveillance studies have demonstrated that resistance among prevalent pathogens is increasing at an alarming rate, leading to greater patient morbidity and mortality from nosocomial infections. Among Gram-positive organisms, the most important resistant pathogens are methicillin- (oxacillin-)resistant Staphylococcus aureus, beta-lactam-resistant and multidrug-resistant pneumococci, and vancomycin-resistant enterococci. Important causes of Gram-negative resistance include extended-spectrum beta-lactamases (ESBLs) in Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis, high-level third-generation cephalosporin (Amp C) beta-lactamase resistance among Enterobacter species and Citrobacter freundii, and multidrug-resistance genes observed in Pseudomonas aeruginosa, Acinetobacter, and Stenotrophomonas maltophilia. In selecting an empiric treatment for a nosocomial infection, one should consider the prevalent resistance patterns. Antimicrobials used for the treatment of nosocomial infections should be effective against any likely resistant pathogens and should not further promote the development of resistance. Recent data suggest that because of ESBLs and high-level amp C beta-lactamase resistances, use of third-generation cephalosporins may be ineffective in many patients with nosocomial infections. In addition, use of these agents may allow overgrowth of inherently resistant enterococci. The role of fluoroquinolones in the empiric treatment of nosocomial infections is also being limited by new resistance patterns and increasing resistance levels. Available antimicrobials with good activity against many resistant pathogens include the carbapenems, piperacillin/tazobactam, and cefepime. In addition, several new agents with good activity against Gram-positive organisms are in development or have been recently released. Appropriate antimicrobial selection, surveillance systems, and effective infection-control procedures are key partners in limiting antimicrobial-resistant pathogen occurrence and spread.
Insights
Antimicrobial resistance in hospital-acquired infections is rising, increasing patient risk. Choosing effective treatments and implementing control measures are crucial to combat resistant pathogens like MRSA and VRE.
Area of Science:
- Infectious Diseases
- Microbiology
- Pharmacology
Background:
- Increasing antimicrobial resistance in prevalent pathogens elevates patient morbidity and mortality from nosocomial infections.
- Key resistant Gram-positive organisms include methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant pneumococci, and vancomycin-resistant enterococci (VRE).
- Significant Gram-negative resistance mechanisms involve extended-spectrum beta-lactamases (ESBLs), high-level Amp C beta-lactamase resistance, and multidrug-resistance genes in various species.
Purpose of the Study:
- To review current trends in antimicrobial resistance among nosocomial pathogens.
- To discuss the implications of resistance patterns for empiric antimicrobial treatment selection.
- To highlight effective antimicrobial agents and strategies for managing infections caused by resistant organisms.
Main Methods:
- Review of surveillance studies on antimicrobial resistance patterns.
- Analysis of the efficacy of different antimicrobial classes against resistant pathogens.
- Discussion of treatment guidelines and infection control strategies.
Main Results:
- Third-generation cephalosporins and fluoroquinolones are becoming less effective due to emerging resistance mechanisms like ESBLs and Amp C beta-lactamases.
- Carbapenems, piperacillin/tazobactam, and cefepime demonstrate good activity against many resistant pathogens.
- New agents with enhanced activity against Gram-positive organisms are emerging.
Conclusions:
- Empiric treatment selection for nosocomial infections must consider prevalent resistance patterns.
- Antimicrobials should be effective against likely resistant pathogens without promoting further resistance.
- Integrated strategies including appropriate antimicrobial selection, surveillance, and infection control are essential to limit antimicrobial-resistant pathogen occurrence.