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Listeria monocytogenes infections: the organism, its pathogenicity and antimicrobial drugs susceptibility
L Riviera1, F Dubini, M G Bellotti
1Institute of Microbiology, University of Catania, Italy.
Abstract:
L. monocytogenes can induce serious, life-threatening infections. Multiple clinical manifestations of the disease include neonatal and perinatal listeriosis, infections in adult immunocompromised patients as well as in normal hosts, with the CNS as the more frequent site involved. Many outbreaks are believed to be food-borne in origin, but there can be other means of transmission. The susceptibility of L. monocytogenes to different antimicrobial drugs is reviewed. Many drugs that are highly effective in vitro show only a moderate activity in vivo, due either to their poor ability to enter the phagocytes and destroy the engulfed bacteria, as with the beta-lactams, ampicillin and amoxicillin, or to their bacteriostatic rather than bactericidal activity, as with the fluoroquinolones, or their affinity for a serum glycoprotein, as with the macrolide antibiotics. The bacterial killing appears to be enhanced by some synergistic drug associations, the best therapeutic results being achieved by trimethoprim-cotrimoxazole and ampicillin plus gentamicin. Other more recent antimicrobial drugs and drug combinations are still under clinical evaluation.
Insights
Listeria monocytogenes causes severe infections, with varying drug effectiveness in vivo. Combination therapies like trimethoprim-cotrimoxazole and ampicillin plus gentamicin show the best results for treating listeriosis.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Listeria monocytogenes (L. monocytogenes) is a pathogen causing severe, life-threatening infections.
- Clinical manifestations include neonatal/perinatal listeriosis, and infections in immunocompromised and normal hosts, frequently affecting the central nervous system (CNS).
- Outbreaks are often food-borne, but other transmission routes exist.
Purpose of the Study:
- To review the antimicrobial drug susceptibility of L. monocytogenes.
- To evaluate the in vitro versus in vivo efficacy of various antimicrobial agents.
- To identify effective therapeutic strategies for listeriosis.
Main Methods:
- Literature review of antimicrobial susceptibility data for L. monocytogenes.
- Analysis of drug efficacy based on in vitro and in vivo studies.
- Evaluation of drug penetration into phagocytes and bactericidal/bacteriostatic activity.
- Assessment of synergistic drug combinations.
Main Results:
- Many antimicrobial drugs effective in vitro show moderate in vivo activity.
- Poor phagocyte entry (e.g., beta-lactams) and bacteriostatic action (e.g., fluoroquinolones) limit in vivo efficacy.
- Macrolide antibiotics exhibit affinity for serum glycoproteins, impacting their effectiveness.
- Synergistic combinations, particularly trimethoprim-cotrimoxazole and ampicillin plus gentamicin, enhance bacterial killing.
Conclusions:
- Antimicrobial drug efficacy against L. monocytogenes varies significantly between in vitro and in vivo settings.
- Optimizing treatment requires considering drug pharmacokinetics and pharmacodynamics, including phagocyte penetration and bactericidal activity.
- Synergistic drug combinations offer improved therapeutic outcomes for listeriosis.
- Ongoing research into novel antimicrobial agents and combinations is crucial.