Spectrum features
Antibiotics of this group possess an exceptionally broad antimicrobial spectrum. Compared to previous generations, they demonstrate higher efficacy against Gram-positive cocci.
Key advantages of the spectrum:
- High resistance to the destructive action of bacterial $\beta$-lactamases.
- Pronounced activity against Pseudomonas aeruginosa among Gram-negative flora.
Pharmacokinetics
These medications are administered exclusively via the parenteral route — intramuscularly or intravenously — with a dosing frequency of 2–3 times a day.
- Distribution: the drugs penetrate exceptionally well into various tissues and organs of the body.
- BBB: successfully cross the blood-brain barrier.
- Elimination: excreted unchanged by the kidneys.
Indications for use
Due to their potent pharmacological properties, these drugs are prescribed in the most complex clinical situations:
- Severe nosocomial (hospital-acquired) infections caused by multidrug-resistant microorganisms.
- Lower respiratory tract pathologies, including pneumonia, lung abscess, and pleural empyema.
- Infectious complications in immunocompromised and neutropenic patients.
Side effects
Like other members of the group, these antibiotics can cause a number of adverse reactions:
- Allergy: urticaria, fever, serum sickness, and anaphylactic shock. It is important to consider cross-allergy: if a reaction to penicillins exists, cephalosporins are contraindicated.
- Organ and systemic toxicity: liver dysfunction, leukopenia, and seizures are possible.
- GI tract and dysbiosis: risk of superinfection, pseudomembranous colitis, oral candidiasis, and diarrhea.
- Local reactions: phlebitis upon intravenous administration.
Briefly: answers to topical questions
What is the mechanism of action of fourth-generation cephalosporins?
The mechanism of action of fourth-generation cephalosporins, like other $\beta$-lactam antibiotics, is bactericidal and based on the disruption of cell wall synthesis. The drugs bind to specific penicillin-binding proteins (PBPs) and inhibit the enzyme transpeptidase. This leads to impaired formation of peptidoglycan, the main component of the cell wall. As a result, its structural integrity is compromised, and an excess of peptidoglycan precursors accumulates within the cell. This serves as a trigger for activating the self-destruction system and autolytic enzymes. Autolysins destroy peptidoglycan, ultimately causing lysis and death of the bacterial cell.
Which Gram-negative pathogens are fourth-generation cephalosporins active against?
Fourth-generation cephalosporins exhibit high activity against a range of Gram-negative bacteria.
- Pseudomonas aeruginosa (Pseudomonas aeruginosa) — the drugs show high efficacy against this pathogen, making them suitable for treating severe hospital-acquired infections and empirical therapy in neutropenia.
They also act against certain other Gram-negative microorganisms, although the specific list of other pathogens is not detailed in the sources.
How do fourth-generation cephalosporins fundamentally differ from third-generation drugs?
Fourth-generation cephalosporins differ from third-generation drugs by having a broader spectrum of activity and increased efficacy against Gram-positive microorganisms.
| Characteristic | Third generation | Fourth generation |
|---|---|---|
| Spectrum of activity | Pronounced activity against Gram-negative flora | Even broader spectrum, combined action |
| Gram-positive flora | Less active | Higher efficacy against Gram-positive cocci |
| Gram-negative flora | High activity | Act against certain Gram-negative bacteria and Pseudomonas aeruginosa |
Both generations possess high resistance to degradation by bacterial $\beta$-lactamases.
What drugs are combined with fourth-generation cephalosporins to treat anaerobic infections?
Sources indicate the combination of fourth-generation cephalosporins, specifically cefepime, with metronidazole for moderate to severe acute cholecystitis.
Fourth generation is "heavy artillery": four letters in the root (Cef-) + Pseudomonas aeruginosa and hospital infections in the crosshairs.
Class and exam questions
What are the main representatives of fourth-generation cephalosporins?
This group includes cefepime and cefpirome.
What are the elimination features of these antibiotics from the body?
The drugs are excreted unchanged by the kidneys.
Can cephalosporins be prescribed to patients with penicillin allergy?
No, due to the presence of cross-allergy, patients with a history of penicillin allergy should not take cephalosporins.
What else to study on this topic
- Comparison of the activity of 1st, 2nd, 3rd, and 4th generation cephalosporins against Gram-positive and Gram-negative flora
- Mechanisms of bacterial resistance to $\beta$-lactamases
- Special considerations for drug use in neutropenic and immunocompromised patients
- Specific toxicity and side effects of cefotetan and cefoperazone (N-methylthiotetrazole side chain)
- Development of pseudomembranous colitis and superinfections during antibiotic therapy
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