Antimicrobial agents for treatment of serious infections caused by resistant Staphylococcus aureus and enterococci

G M Eliopoulos1

  • 1Department of Medicine, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, USA. geliopou@bidmc.harvard.edu

Insights

Antimicrobial resistance in staphylococci and enterococci necessitates exploring older and newer drugs. Licensed agents like linezolid and daptomycin show in vitro activity, but clinical uses vary, with new options emerging.

Area of Science:

  • Microbiology and Infectious Diseases
  • Pharmacology
  • Clinical Medicine

Background:

  • Rising antimicrobial resistance in staphylococci and enterococci poses clinical challenges.
  • Traditional antimicrobial agents are increasingly failing to treat resistant infections.
  • Understanding alternative and novel antimicrobial agents is crucial for effective treatment.

Purpose of the Study:

  • To review the roles of older and newer antimicrobial agents against resistant staphylococci and enterococci.
  • To highlight licensed agents with in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE).
  • To discuss the varying clinical indications of these agents and emerging treatment options.

Main Methods:

  • Literature review of antimicrobial agents.
  • Analysis of in vitro activity data against resistant pathogens.
  • Comparison of approved clinical indications for key antimicrobial drugs.

Main Results:

  • Clindamycin and trimethoprim-sulfamethoxazole are used for community-acquired MRSA infections.
  • Quinupristin-dalfopristin, linezolid, daptomycin, and tigecycline exhibit in vitro activity against MRSA and VRE.
  • Significant differences exist in the approved clinical indications for these licensed agents.

Conclusions:

  • A range of antimicrobial agents, both established and novel, are available for treating resistant staphylococcal and enterococcal infections.
  • Careful consideration of drug indications and pathogen susceptibility is essential for optimal patient outcomes.
  • Ongoing research into new antimicrobial agents promises to expand future treatment strategies.

Related Concept Videos

Antimicrobial Effectiveness01:28

Antimicrobial Effectiveness

The effectiveness of antimicrobial agents depends on various factors influencing their ability to eliminate microbial populations. Larger microbial populations require more time for complete eradication, emphasizing the importance of population size analysis when evaluating antimicrobial efficacy.Microbial resistance to antimicrobial agents varies significantly. Highly resilient microorganisms include endospores, gram-negative bacteria, and non-enveloped viruses, while prions are exceptionally...
Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Staphylococcal Skin Infections01:29

Staphylococcal Skin Infections

Staphylococcus aureus is a Gram-positive coccus that resides harmlessly on the skin and mucous membranes of healthy individuals. When the skin barrier is breached, it can shift from a commensal to an opportunistic pathogen. This transition is facilitated by surface adhesins, such as clumping factor B and S. aureus surface protein G (SasG), which bind to structural proteins, including loricrin and cytokeratin, in the damaged epidermis. Protein A, another key factor, binds the Fc region of...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Inhibitors of Bacterial Protein Synthesis01:25

Inhibitors of Bacterial Protein Synthesis

Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...