AI Article Synopsis
- The study aimed to assess how effective macrolides (erythromycin, azithromycin) and fluoroquinolones (levofloxacin, moxifloxacin) are at inhibiting Legionella pneumophila using intracellular tests.
- Results showed that fluoroquinolones significantly outperformed macrolides in inhibiting the bacteria, with levofloxacin and moxifloxacin exhibiting nearly identical effectiveness.
- Additionally, azithromycin proved to be more effective than erythromycin in reducing the intracellular presence of Legionella pneumophila.
Article Abstract
Objective: To evaluate the activity of macrolides and fluoroquinolones against Legionella pneumophila by intracellular susceptibility testing.
Methods: Minimum inhibitory concentration (MIC) was determined by standard agar dilution test according to the CLSI. For intracellular assays, legionella pneumonia was used to infect human monocytic cell line THP-1. Erythromycin, azithromycin, levofloxacin and moxifloxacin at 1 × MIC, 4 × MIC, 8 × MIC were added following phagocytosis. Number of viable bacteria was enumerated at 24 h on BCYE (buffered charcoal yeast extract) agar in duplicates using standard plate count method. The result was expressed as percentage inhibition. Mann-Whitney U test was used to determine the significant differences in mean percentage inhibition between agents.
Results: Percentage inhibition at 24 h were as follows: Erythromycin 1 × MIC (50.18 ± 27.29)%, 4 × MIC (79.48 ± 20.08)%, 8 × MIC (91.46 ± 8.70)%; Azithromycin 1 × MIC (66.77 ± 26.18)%, 4 × MIC (91.73 ± 8.72)%, 8 × MIC (97.10 ± 3.37)%; Levofloxacin 1 × MIC (99.84 ± 0.25)%, 4 × MIC (99.99 ± 0.02)%, 8 × MIC (99.99 ± 0.01)%; Moxifloxacin 1 × MIC (99.90 ± 0.10)%, 4 × MIC (99.99 ± 0.03)%, 8 × MIC (99.99 ± 0.03)%. The fluoroquinolones showed greater inhibitory activity than macrolides against legionella pneumophila(u = 1.0, 2.0, 5.0, P < 0.05). Levofloxacin and moxifloxacin had the same intracellular activity against legionella pneumophila (u = 190, 183, 217, P > 0.05). Azithromycin was more effective than erythromycin in inhibiting intracellular legionella pneumophila (u = 132, 125, 128, P < 0.05).
Conclusions: The fluoroquinolones were more active than macrolides against legionella pneumophila. The intracellular activity of levofloxacin against legionella pneumophila appeared to be similar to moxifloxacin. Azithromycin was demonstrated to have superior activity against legionella pneumophila compared with erythromycin.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
LD-transpeptidase-mediated cell envelope remodeling enables developmental transitions and survival in and .
J Bacteriol
January 2025
Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA.
and are two phylogenetically related bacterial pathogens that exhibit extreme intrinsic resistance when they enter into a dormancy-like state. This enables both pathogens to survive extended periods in growth-limited environments. Survival is dependent upon their ability to undergo developmental transitions into two phenotypically distinct variants, one specialized for intracellular replication and another for prolonged survival in the environment and host.
View Article and Find Full Text PDFOccurrence of macrolides resistance in Legionella pneumophila ST188: results of the Belgian epidemiology and resistome investigation of clinical isolates.
Int J Infect Dis
January 2025
National reference centre for Legionella pneumophila, Department of Microbiology, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium.
Introduction: The incidence of Legionnaires' disease (LD) steadily increases worldwide. Although Legionella pneumophila is known as pathogenic, systematic investigations into antibiotic resistance are scarce, and reports of resistance in isolates are recently emerging.
Methods: Clinical cases and metadata reported to the Belgian National Reference Centre between 2011 and 2022 were retrospectively analysed.
Severe pneumonia due to concurrent Legionella pneumophila and Acinetobacter baumannii infections: a case report.
BMC Pulm Med
January 2025
Department of Respiratory and Critical Care Medicine, Lishui Hospital of Traditional Chinese Medicine Affiliated to Zhejiang University of Traditional Chinese Medicine, No. 800 Zhongshan Road, Liandu District, Lishui, Zhejiang, 323000, China.
Background: Legionella pneumophila is an uncommon pathogen causing community-acquired atypical pneumonia. Acinetobacter baumannii is a major pathogen responsible for hospital-acquired pneumonia, but it rarely causes serious infections in a community setting. Without prompt and appropriate treatments, infection from either of these two pathogens can cause a high mortality rate.
View Article and Find Full Text PDFAntimicrobial susceptibility and epidemiological types of Legionella pneumophila human isolates from Italy (1987-2020).
J Glob Antimicrob Resist
January 2025
Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy; ESCMID Study Group for Legionella Infections (ESGLI), Basel, Switzerland. Electronic address:
Background: Although antimicrobial resistance has not yet emerged as an overarching problem for Legionella pneumophila (Lp) infection, the description of clinical and environmental strains resistant to fluoroquinolones and macrolides is a cause of concern. This study aimed to investigate the antimicrobial susceptibility of Lp human isolates in Italy.
Methods: A total of 204 Lp clinical isolates were tested for sensitivity to nine antibiotics using the broth microdilution assay (BMD).
Rapid Icm/Dot T4SS Inactivation Prevents Resuscitation of Heat-Induced VBNC Legionella pneumophila by Amoebae.
Environ Microbiol
January 2025
Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland.
Legionella pneumophila, the causative agent of Legionnaires' disease, employs the Icm/Dot Type IV secretion system (T4SS) to replicate in amoebae and macrophages. The opportunistic pathogen responds to stress by forming 'viable but non-culturable' (VBNC) cells, which cannot be detected by standard cultivation-based techniques. In this study, we document that L.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!