#Antibiotic susceptibility of #Legionella pneumophila strains isolated in #England and #Wales 2007–17 (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Antibiotic susceptibility of Legionella pneumophilastrains isolated in England and Wales 2007–17

R E Wilson, R L R Hill, V J Chalker, M Mentasti, D Ready

Journal of Antimicrobial Chemotherapy, dky253, https://doi.org/10.1093/jac/dky253

Published: 24 July 2018

 

Abstract

Objectives

Antibiotic susceptibility of Legionella pneumophila is poorly understood, with treatment of Legionnaires’ disease often based on empirical choice. The aim of this study was to determine the antibiotic susceptibility of L. pneumophilastrains.

Methods

Antibiotic susceptibility of 92 L. pneumophila strains isolated in England and Wales between 2007 and 2017 was determined using a microbroth dilution methodology for each agent tested. MICs and MBCs were determined and compared with published intracellular concentrations of each agent tested.

Results

The MIC range of erythromycin was 0.06–1 mg/L, the MIC range of rifampicin was 0.0001 mg/L, the MIC range of ciprofloxacin was 0.004–0.25 mg/L and the MIC range of levofloxacin and moxifloxacin was 0.03–0.25 mg/L. The MBC range of erythromycin was 1–32 mg/L, but the MBC range of ciprofloxacin was the same as the MIC range. For levofloxacin and moxifloxacin the MBC range was elevated by one dilution and two dilutions, respectively. Typically, intracellular bronchial secretion concentrations of erythromycin might be expected to reach a suitable level to exceed the MIC range; however, 91 of 92 (98.9%) isolates had an MBC below the expected intracellular concentrations, which indicated erythromycin may have variable efficacy. MIC and MBC values of ciprofloxacin, levofloxacin and moxifloxacin were below achievable intracellular levels within bronchial secretions. Comparison of the MIC/MBC correlation showed very little clustering for erythromycin, but strong clustering for levofloxacin and to a lesser extent ciprofloxacin.

Conclusions

Use of the MIC/MBC linkage analysis seems an appropriate way forward for antimicrobial susceptibility testing and supports current guidance recommending levofloxacin for the treatment of Legionnaires’ disease.

Topic: antibiotics – rifampin – erythromycin – genetic linkage analysis – ciprofloxacin – bodily secretions – legionella pneumophila – legionnaires’ disease – country of wales – levofloxacin – moxifloxacin – antimicrobial susceptibility – antimicrobial susceptibility test – dilution technique – dilute (action) – malnutrition-inflammation-cachexia syndrome

Issue Section: ORIGINAL RESEARCH

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Keywords: Antibiotics; Drugs Resistance; Legionalla pneumophila; England; Wales; rifampin; erythromycin; ciprofloxacin; levofloxacin; moxifloxacin.

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Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.