A review of telavancin activity in in vitro biofilms and animal models of biofilm-associated infections

Antibiotics with antibiofilm activity - rifampicin and beyond

The management of prosthetic joint infections is a complex and multilayered process that is additionally complicated by the formation of bacterial biofilm. Foreign material provides the ideal grounds for the development of an intricate matrix that hinders treatment and creates a difficult environment for antibiotics to act. Surgical intervention is often warranted but requires appropriate adjunctive therapy. Despite available guidelines, several aspects of antibiotic therapy with antibiofilm activity lack clear definition. Given the escalating challenges posed by antimicrobial resistance, extended treatment durations, and tolerance issues, it is essential to ensure that antimicrobials with antibiofilm activity are both potent and diverse. Evidence of biofilm-active drugs is highlighted, and alternatives to classical regimens are further discussed.

Pharmacokinetics and safety of a single dose of telavancin in pediatric subjects 2-17 years of age

Antimicrobial resistance increases infection morbidity in both adults and children, necessitating the development of new therapeutic options. Telavancin, an antibiotic approved in the United States for certain bacterial infections in adults, has not been examined in pediatric patients. The objectives of this study were to evaluate the short-term safety and pharmacokinetics (PK) of a single intravenous infusion of telavancin in pediatric patients. Single-dose safety and PK of 10 mg/kg telavancin was investigated in pediatric subjects >12 months to ≤17 years of age with known or suspected bacterial infection. Plasma was collected up to 24-h post-infusion and analyzed for concentrations of telavancin and its metabolite for noncompartmental PK analysis. Safety was monitored by physical exams, vital signs, laboratory values, and adverse events following telavancin administration. Twenty-two subjects were enrolled: 14 subjects in Cohort 1 (12-17 years), 7 subjects in Cohort 2 (6-11 years), and 1 subject in Cohort 3 (2-5 years). A single dose of telavancin was well-tolerated in all pediatric age cohorts without clinically significant effects. All age groups exhibited increased clearance of telavancin and reduced exposure to telavancin compared to adults, with mean peak plasma concentrations of 58.3 µg/mL (Cohort 1), 60.1 µg/mL (Cohort 2), and 53.1 µg/mL (Cohort 3). A 10 mg/kg dose of telavancin was well tolerated in pediatric subjects. Telavancin exposure was lower in pediatric subjects compared to adult subjects. Further studies are needed to determine the dose required in phase 3 clinical trials in pediatrics.

Two Novel Semisynthetic Lipoglycopeptides Active against Staphylococcus aureus Biofilms and Cells in Late Stationary Growth Phase

The increase in antibiotic resistance among Gram-positive bacteria underscores the urgent need to develop new antibiotics. New antibiotics should target actively growing susceptible bacteria that are resistant to clinically accepted antibiotics including bacteria that are not growing or are protected in a biofilm environment. In this paper, we compare the in vitro activities of two new semisynthetic glycopeptide antibiotics, MA79 and ERJ390, with two clinically used glycopeptide antibiotics-vancomycin and teicoplanin. The new antibiotics effectively killed not only exponentially growing cells of Staphylococcus aureus, but also cells in the stationary growth phase and biofilm.

Options and Limitations in Clinical Investigation of Bacterial Biofilms

Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.

Developments in Glycopeptide Antibiotics

Glycopeptide antibiotics (GPAs) are a key weapon in the fight against drug resistant bacteria, with vancomycin still a mainstream therapy against serious Gram-positive infections more than 50 years after it was first introduced. New, more potent semisynthetic derivatives that have entered the clinic, such as dalbavancin and oritavancin, have superior pharmacokinetic and target engagement profiles that enable successful treatment of vancomycin-resistant infections. In the face of resistance development, with multidrug resistant (MDR) S. pneumoniae and methicillin-resistant Staphylococcus aureus (MRSA) together causing 20-fold more infections than all MDR Gram-negative infections combined, further improvements are desirable to ensure the Gram-positive armamentarium is adequately maintained for future generations. A range of modified glycopeptides has been generated in the past decade via total syntheses, semisynthetic modifications of natural products, or biological engineering. Several of these have undergone extensive characterization with demonstrated in vivo efficacy, good PK/PD profiles, and no reported preclinical toxicity; some may be suitable for formal preclinical development. The natural product monobactam, cephalosporin, and β-lactam antibiotics all spawned multiple generations of commercially and clinically successful semisynthetic derivatives. Similarly, next-generation glycopeptides are now technically well positioned to advance to the clinic, if sufficient funding and market support returns to antibiotic development.

Activity of telavancin against Gram-positive pathogens isolated from bone and joint infections in North American, Latin American, European and Asia-Pacific nations

Telavancin was tested against a worldwide collection of Gram-positive pathogens (967) isolated from bone and joint infections (BJI). Most BJI isolates were from the United States (US) (49.9%) followed by Europe (26.4%), Latin America (LATAM; 14.4%), and Asia-Pacific (APAC; 9.3%). Organisms were tested by broth microdilution susceptibility methods. S. aureus (66.4%; range of 48.9% in APAC to 71.2% in LATAM) was the most common pathogen and had a 35.7% methicillin resistance (MRSA) rate and telavancin MIC_50/90 of 0.03/0.06μg/mL (100% susceptible). MRSA isolates that were daptomycin resistant (0.2%) were telavancin susceptible. CoNS (12.1% of BJI) had telavancin MIC_50/90 at 0.06/0.06μg/mL, and 13.7% were teicoplanin resistant. Enterococci had telavancin MIC_50/90 at 0.12/0.25μg/mL, but telavancin inhibited vancomycin-susceptible isolates at ≤0.25μg/mL. All streptococci were telavancin susceptible (MIC₉₀, 0.03-0.06μg/mL). The in vitro results presented here warrant further investigations to access the role of telavancin for BJI/osteomyelitis treatment caused by Gram-positive cocci.

Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

We used in vitro and in vivo models of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) in the specific context of an established biofilm. The results demonstrated that, under in vitro conditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when tested in vivo in a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associated S. aureus infections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

Telavancin in the treatment of Staphylococcus aureus hospital-acquired and ventilator-associated pneumonia: clinical evidence and experience

Telavancin (TLV) is a lipoglycopeptide derivative of vancomycin (VAN), which has activity against Gram-positive aerobic bacteria, and is especially effective against methicillin-resistant Staphylococcus aureus (MRSA) and Gram-positive bacteria resistant to VAN. Comparative clinical studies of TLV have demonstrated noninferiority compared with VAN in the treatment of hospital-acquired Gram-positive pneumonia, with high cure rates for TLV-treated patients with monomicrobial S. aureus infection, including isolates with reduced VAN susceptibility. The results based on the patients' clinical response were supported by supplemental post-hoc analyses of 28-day mortality. In Europe and the USA, TLV is approved as a useful alternative for patients with difficult-to-treat, hospital-acquired MRSA pneumonia when there are very few alternatives. The present article reviews TLV's pharmacological characteristics and clinical efficacy resulting from clinical trials giving a detailed picture of its properties and position in the management of hospital-acquired pneumonia.

Drug treatments for prosthetic joint infections in the era of multidrug resistance

INTRODUCTION

Despite many advances, the management of prosthetic joint infection is still a complex issue. Moreover, in recent years the problem of antimicrobial resistance has emerged as an important challenge.

AREAS COVERED

We analysed recent advances in different aspects of prosthetic joint infections. The importance of biofilms needs to be considered for antibiotic selection because, when embedded in these structures, bacteria acquire resistant behaviour. Moreover, the presence of resistance mechanisms in some species of organisms increases the difficulty of management. In this sense, the growing importance of methicillin-resistant staphylococci, multidrug-resistant Enterobacteriaceae or Pseudomonas aeruginosa is of increasing concern. Together with these organisms, others with constitutive resistance against most antibiotics (like Enterococcus sp., mycobacteria or fungi) represent a similar problem for selection of therapy. Research into new materials that can be used as drug carriers opens a new field for management of these infections and will likely come to the front line in the coming years.

EXPERT OPINION

Individualised therapies should carefully consider the aetiology, pathogenesis and antimicrobial susceptibility. Satisfactory clinical outcome could be further fostered by enhancing the multidisciplinary approach, with better collaboration in the antibiotic selection and the surgical management.