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Changing patterns of hospital infections: implications for therapy. Changing mechanisms of bacterial resistance
Abstract:
During the past decade there has been a marked increase in resistance of bacteria to antimicrobial agents. Microorganisms have developed the ability to make altered receptors for antimicrobial agents, have prevented agents from reaching their receptors within the bacterial cell, now have enzymes to destroy antibiotics, and have resistant metabolic pathways. Altered penicillin receptors, penicillin-binding proteins, have been found in Streptococcus pneumoniae, Streptococcus faecalis, Staphylococcus aureus, Neisseria gonorrhoeae, Clostridium, and Pseudomonas aeruginosa. Resistance based on decreased entry of drugs has been found for penicillins, cephalosporins, aminoglycosides, and tetracyclines in the Enterobacteriaceae and Pseudomonas aeruginosa. Beta-lactamase resistance has increased significantly being encountered in Neisseria, Haemophilus, Enterobacteriaceae, and Pseudomonas species. Chromosomal inducible beta-lactamases, which function as cephalosporinases, have been a particular problem in Enterobacter and Citrobacter species, and organisms resistant to the third-generation cephalosporins have been isolated from patients. It is clear that beta-lactamases and changes in cell wall permeability will play an extremely important role in the future of the new penicillins and cephalosporins.
Insights
Bacterial resistance to antimicrobial agents is increasing due to altered receptors, reduced drug entry, and enzymes like beta-lactamases. These mechanisms, particularly beta-lactamases and cell wall permeability changes, will impact future antibiotics.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Antimicrobial resistance is a growing global health concern.
- Microorganisms have evolved diverse mechanisms to evade antibiotic action.
Purpose of the Study:
- To review the increasing resistance of bacteria to antimicrobial agents.
- To highlight key resistance mechanisms and their implications for future antibiotic development.
Main Methods:
- Literature review of antimicrobial resistance trends and mechanisms.
- Analysis of bacterial resistance pathways including altered receptors, drug entry, and enzymatic degradation.
Main Results:
- Increased resistance observed in Streptococcus, Staphylococcus, Neisseria, Haemophilus, Enterobacteriaceae, and Pseudomonas species.
- Key resistance mechanisms include altered penicillin-binding proteins, decreased drug permeability, and significant increases in beta-lactamase production.
- Chromosomal inducible beta-lactamases pose a challenge, leading to resistance against third-generation cephalosporins.
Conclusions:
- Beta-lactamases and altered cell wall permeability are critical factors in bacterial resistance.
- These mechanisms will significantly influence the development and efficacy of future penicillins and cephalosporins.