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Introduction: Evolving needs in respiratory tract infections
1Division of Infectious Diseases, McMaster University, Hamilton, Ontario, Canada.
Abstract:
Two issues that have become clinically relevant to the treatment of pneumonia over the past few years are the development of antibiotic resistance among respiratory pathogens and the increasing importance of the atypical respiratory pathogens---Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella spp. Resistance has become an important issue in Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus and Gram-negative rods. The ways by which bacteria become resistant to antibiotics include production of antibiotic-modifying enzymes, reduced access to target sites, efflux of antibiotic, change in the bacterial target site and the bypassing of inhibited pathways. In Streptococcus pneumoniae that are penicillin resistant, the mechanism is through alteration of the target site for penicillins (penicillin-binding proteins) and this may also confer resistance to some cephalosporins. Multidrug resistance has also been reported in some strains of pneumococci. Of particular concern is resistance to macrolides mediated by the ermAM gene, which also confers resistance to lincosamides and streptogramin-B drugs. In Staphylococcus aureus, resistance to virtually all beta-lactam drugs is mediated by acquisition of the mecA gene, which codes for the drug-resistant beta-lactam target PBP2a. Antimicrobials are now needed that have enhanced activity against aerobic Gram-negative rods, atypical respiratory pathogens and Gram-positive cocci.
Insights
Antibiotic resistance in pneumonia is rising, particularly with Streptococcus pneumoniae and Staphylococcus aureus. New antimicrobials are needed to combat resistant bacteria and atypical pathogens.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Antibiotic resistance in respiratory pathogens is a growing clinical concern.
- Atypical pathogens like Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella spp. are increasingly important in pneumonia treatment.
- Resistance mechanisms include enzyme production, reduced drug access, efflux pumps, target modification, and pathway bypassing.
Purpose of the Study:
- To review the clinical relevance of antibiotic resistance in pneumonia.
- To discuss the mechanisms of antibiotic resistance in key pathogens.
- To highlight the need for novel antimicrobial agents.
Main Methods:
- Literature review of recent clinical and microbiological studies.
- Analysis of resistance mechanisms in Streptococcus pneumoniae, Staphylococcus aureus, and Gram-negative rods.
- Discussion of atypical pathogens' role in pneumonia.
Main Results:
- Penicillin resistance in Streptococcus pneumoniae involves altered penicillin-binding proteins, potentially conferring cephalosporin resistance.
- Multidrug resistance is observed in pneumococci, with macrolide resistance mediated by the ermAM gene.
- Staphylococcus aureus resistance to beta-lactams is linked to the mecA gene and PBP2a.
- Atypical pathogens pose a significant challenge in pneumonia treatment.
Conclusions:
- There is an urgent need for antimicrobials with enhanced activity against Gram-negative rods, atypical pathogens, and Gram-positive cocci.
- Understanding resistance mechanisms is crucial for developing effective treatment strategies.
- Continued surveillance and development of new antibiotics are essential for managing pneumonia effectively.