Broth microdilution protocol for determining antimicrobial susceptibility of Legionella pneumophila to clinically relevant antimicrobials.

Currently there is no detailed, internationally agreed protocol defined to evaluate antimicrobial susceptibility testing (AST) for Legionella pneumophila (required to establish epidemiological cut-off value or "ECOFF" boundaries); therefore, antimicrobial resistance in these isolates cannot be defined. AST methods utilising media containing activated charcoal as an ingredient, to enable Legionella growth, are unreliable as noted in an internationally authored opinion paper and a new gold standard is required. Here we define a detailed protocol for broth microdilution (BMD) using defined cell culture collection-deposited control reference strains (Philadelphia-1 and Knoxville-1) as well as two accessible reference strains with moderately (lpeAB-carrying) and markedly (23S rRNA mutation-carrying) elevated azithromycin minimum inhibitory concentration (MIC).

test of the novel antibiotic lefamulin alone and in combination with doxycycline against .

, a sexually transmitted bacterium, is a significant cause of urethritis in men and various reproductive tract infections in women, including cervicitis, pelvic inflammatory disease, endometritis, and potentially infertility. Treatment has become increasingly challenging due to the emergence of resistance to both first-line (azithromycin) and second-line (moxifloxacin) antibiotics. The need for new treatment options is critical.

In Vivo Immune-Modulatory Activity of Lefamulin in an Influenza Virus A (H1N1) Infection Model in Mice.

Lefamulin is a first-in-class systemic pleuromutilin antimicrobial and potent inhibitor of bacterial translation, and the most recent novel antimicrobial approved for the treatment of community-acquired pneumonia (CAP). It exhibits potent antibacterial activity against the most prevalent bacterial pathogens that cause typical and atypical pneumonia and other infectious diseases. Early studies indicate additional anti-inflammatory activity.

Phenotypic and genotypic antimicrobial susceptibility patterns of the emerging human respiratory pathogen Mycoplasma amphoriforme isolated from the UK and Denmark.

Objectives: To determine the phenotypic and genotypic antibiotic susceptibility of Mycoplasma amphoriforme isolates recovered from patients in the UK and Denmark.

Methods: Seven isolates of M. amphoriforme were examined for antimicrobial susceptibility to seven antibiotics using the microbroth dilution assay in line with the CLSI guidelines for mycoplasmas.

A plain language summary of how lefamulin alone can be used to treat pneumonia caught outside of the hospital due to common bacterial causes, including drug-resistant bacteria.

What Is This Summary About?: Bacterial pneumonia is an infection of the lung caused by bacteria that is potentially deadly, costly, and affects millions of people worldwide every year. Treatment is becoming more challenging-many current treatments no longer work well because some strains of bacteria that cause pneumonia have become resistant to current antibiotics. Many of the antibiotics that do still work have undesirable side effects.

Lefamulin in Patients with Community-Acquired Bacterial Pneumonia Caused by Atypical Respiratory Pathogens: Pooled Results from Two Phase 3 Trials.

Lefamulin was the first systemic pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia based on two phase 3 trials (Lefamulin Evaluation Against Pneumonia [LEAP]-1 and LEAP-2). This pooled analysis evaluated lefamulin efficacy and safety in adults with community-acquired bacterial pneumonia caused by atypical pathogens (, , and ). In LEAP-1, participants received intravenous lefamulin 150 mg every 12 h for 5-7 days or moxifloxacin 400 mg every 24 h for 7 days, with optional intravenous-to-oral switch.

Determination of In Vitro Antimicrobial Susceptibility for Lefamulin (Pleuromutilin) for Spp. and .

Lefamulin is the first of the pleuromutilin class of antimicrobials to be available for therapeutic use in humans. Minimum inhibitory concentrations of lefamulin were determined by microbroth dilution for 90 characterised clinical isolates (25  , 25 and 40 ). All isolates possessed lefamulin MICs of ≤0.

Pooled microbiological findings and efficacy outcomes by pathogen in adults with community-acquired bacterial pneumonia from the Lefamulin Evaluation Against Pneumonia (LEAP) 1 and LEAP 2 phase 3 trials of lefamulin versus moxifloxacin.

Objectives: Lefamulin, a pleuromutilin antibiotic approved for community-acquired bacterial pneumonia (CABP), was evaluated for microbiological efficacy in a prespecified pooled analysis of LEAP 1 and 2 phase 3 clinical trial data in patients with CABP.

Methods: In LEAP 1, adults (PORT risk class III‒V) received intravenous (IV) lefamulin 150 mg every 12 h (q12h) for 5‒7 days or moxifloxacin 400 mg every 24 h (q24h) for 7 days, with optional IV-to-oral switch. In LEAP 2, adults (PORT II‒IV) received oral lefamulin 600 mg q12h for 5 days or moxifloxacin 400 mg q24h for 7 days.

Anti-inflammatory activity of lefamulin versus azithromycin and dexamethasone in vivo and in vitro in a lipopolysaccharide-induced lung neutrophilia mouse model.

Several antibiotics demonstrate both antibacterial and anti-inflammatory/immunomodulatory activities and are used to treat inflammatory pulmonary disorders. Lefamulin is a pleuromutilin antibiotic approved to treat community-acquired bacterial pneumonia (CABP). This study evaluated lefamulin anti-inflammatory effects in vivo and in vitro in a lipopolysaccharide-induced lung neutrophilia model in which mouse airways were challenged with intranasal lipopolysaccharide.

Oral Lefamulin vs Moxifloxacin for Early Clinical Response Among Adults With Community-Acquired Bacterial Pneumonia: The LEAP 2 Randomized Clinical Trial.

Importance: New antibacterials are needed to treat community-acquired bacterial pneumonia (CABP) because of growing antibacterial resistance and safety concerns with standard care.

Objective: To evaluate the efficacy and adverse events of a 5-day oral lefamulin regimen in patients with CABP.

Design, Setting, And Participants: A phase 3, noninferiority randomized clinical trial conducted at 99 sites in 19 countries that included adults aged 18 years or older with a Pneumonia Outcomes Research Team (PORT) risk class of II, III, or IV; radiographically documented pneumonia; acute illness; 3 or more CABP symptoms; and 2 or more vital sign abnormalities.

Pharmacokinetics/pharmacodynamics of lefamulin in a neutropenic murine pneumonia model with Staphylococcus aureus and Streptococcus pneumoniae.

Objectives: To present results of preclinical studies that supported further development of lefamulin for treating patients with community-acquired bacterial pneumonia (CABP).

Methods: The effect of bovine lung surfactant on the antibacterial activity of lefamulin against Streptococcus pneumoniae and Staphylococcus aureus was determined by broth microdilution assay. In vitro accumulation of lefamulin was evaluated in J774 mouse macrophages.

Efficacy and Safety of Intravenous-to-oral Lefamulin, a Pleuromutilin Antibiotic, for the Treatment of Community-acquired Bacterial Pneumonia: The Phase III Lefamulin Evaluation Against Pneumonia (LEAP 1) Trial.

Background: Lefamulin, a pleuromutilin antibiotic, is active against pathogens commonly causing community-acquired bacterial pneumonia (CABP). The Lefamulin Evaluation Against Pneumonia (LEAP 1) study was a global noninferiority trial to evaluate the efficacy and safety of lefamulin for the treatment of CABP.

Methods: In this double-blind study, adults with CABP of Pneumonia Outcomes Research Team risk class ≥III were randomized 1:1 to receive lefamulin at 150 mg intravenously (IV) every 12 hours or moxifloxacin at 400 mg IV every 24 hours.

Low Prevalence of Gram-Positive Isolates Showing Elevated Lefamulin MIC Results during the SENTRY Surveillance Program for 2015-2016 and Characterization of Resistance Mechanisms.

This study investigated the molecular mechanisms possibly associated with non-wild-type MICs for lefamulin among staphylococci and streptococci included in the lefamulin surveillance program from 2015 to 2016. A total of 2,919 , 276 coagulase-negative staphylococci (CoNS), 3,923 , 389 β-hemolytic, and 178 viridans group streptococci isolates were included in the surveillance studies. Eleven (0.

Antibacterial Activity of Lefamulin against Pathogens Most Commonly Causing Community-Acquired Bacterial Pneumonia: SENTRY Antimicrobial Surveillance Program (2015-2016).

Lefamulin, the first semisynthetic pleuromutilin antibacterial for intravenous and oral treatment of community-acquired bacterial pneumonia (CABP), and comparators were evaluated for activity against a global collection of pathogens commonly causing CABP ( = 8595) from the 2015 and 2016 SENTRY Antimicrobial Surveillance Program. Lefamulin was highly active against the pathogens , including multidrug-resistant and extensively drug-resistant strains (MIC for total and resistant subsets, 0.06/0.

Activity of Lefamulin against Sexually Transmitted Bacterial Pathogens.

The pleuromutilin antibiotic lefamulin demonstrated activity against the most relevant bacterial pathogens causing sexually transmitted infections (STI), including (MIC, 0.02/0.04 mg/liter; = 15), susceptible and multidrug-resistant (MIC range, 0.

Activity of the Novel Pleuromutilin Lefamulin (BC-3781) and Effect of Efflux Pump Inactivation on Multidrug-Resistant and Extensively Drug-Resistant Neisseria gonorrhoeae.

We evaluated the activity of the novel semisynthetic pleuromutilin lefamulin, inhibiting protein synthesis and growth, and the effect of efflux pump inactivation on clinical gonococcal isolates and reference strains ( = 251), including numerous multidrug-resistant and extensively drug-resistant isolates. Lefamulin showed potent activity against all gonococcal isolates, and no significant cross-resistance to other antimicrobials was identified. Further studies of lefamulin are warranted, including selection and mechanisms of resistance, pharmacokinetics/pharmacodynamics, optimal dosing, and performance in randomized controlled trials.

A novel pleuromutilin antibacterial compound, its binding mode and selectivity mechanism.

The increasing appearance of pathogenic bacteria with antibiotic resistance is a global threat. Consequently, clinically available potent antibiotics that are active against multidrug resistant pathogens are becoming exceedingly scarce. Ribosomes are a main target for antibiotics, and hence are an objective for novel drug development.

In Vitro Activities of Lefamulin and Other Antimicrobial Agents against Macrolide-Susceptible and Macrolide-Resistant Mycoplasma pneumoniae from the United States, Europe, and China.

Lefamulin, an investigational pleuromutilin, was tested against a collection of 18 macrolide-susceptible and 42 macrolide-resistant Mycoplasma pneumoniae strains, and the results were compared with those of azithromycin, erythromycin, tetracycline, doxycycline, and moxifloxacin testing. Lefamulin was highly active against all strains tested, with all MICs at ≤0.008 μg/ml.

Pleuromutilins: Potent Drugs for Resistant Bugs-Mode of Action and Resistance.

Pleuromutilins are antibiotics that selectively inhibit bacterial translation and are semisynthetic derivatives of the naturally occurring tricyclic diterpenoid pleuromutilin, which received its name from the pleuromutilin-producing fungus Pleurotus mutilus Tiamulin and valnemulin are two established derivatives in veterinary medicine for oral and intramuscular administration. As these early pleuromutilin drugs were developed at a time when companies focused on major antibacterial classes, such as the β-lactams, and resistance was not regarded as an issue, interest in antibiotic research including pleuromutilins was limited. Over the last decade or so, there has been a resurgence in interest to develop this class for human use.

In Vitro Activity of Lefamulin Tested against Streptococcus pneumoniae with Defined Serotypes, Including Multidrug-Resistant Isolates Causing Lower Respiratory Tract Infections in the United States.

Lefamulin was evaluated against various Streptococcus pneumoniae serotypes that were collected from adults with lower respiratory tract infections. Lefamulin exhibited MIC50 and MIC90 values of 0.12 and 0.

Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus.

The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S.

Antimicrobial activity of the pleuromutilin antibiotic BC-3781 against bacterial pathogens isolated in the SENTRY antimicrobial surveillance program in 2010.

BC-3781 is a novel semisynthetic pleuromutilin antibiotic inhibiting bacterial protein synthesis. BC-3781 has completed a phase 2 clinical trial in acute bacterial skin and skin structure infections (ABSSSI). Its antibacterial spectrum additionally covers the predominant pathogens causing community-acquired bacterial pneumonia (CABP).