Skin Structure Infections Research Articles

No Evidence for Ceftobiprole-Induced Immune Hemolytic Anemia in Three Phase 3 Clinical Trials.

PurposeDrug-induced immune hemolytic anemia (DIIHA) is a rare but serious adverse event associated with a number of drugs, including second- and third-generation cephalosporins. A positive direct antiglobulin test (DAT) is a reliable finding in DIIHA, but positive results without evidence of hemolysis can occur, particularly in hospitalized patients. There have been no reports of hemolytic anemia in four previous Phase 3 trials or from post-marketing surveillance of the advanced-generation, broad-spectrum cephalosporin, ceftobiprole. The aim of this analysis was to review the incidence of positive DAT results and any evidence of hemolytic anemia from three recent Phase 3 trials of ceftobiprole.Patients and MethodsPatients were enrolled in three Phase 3 randomized controlled trials: 94 pediatric patients with pneumonia received ceftobiprole in the BPR-PIP-002 trial; 335 adults with acute bacterial skin and skin structure infections received ceftobiprole in the TARGET trial; and 201 adults with Staphylococcus aureus bacteremia have been randomized 1:1 to ceftobiprole or daptomycin ± aztreonam in the ongoing ERADICATE trial. In all three trials, DAT results were obtained at baseline, and follow-up tests were performed either at the test of cure (TOC) visit (BPR-PIP-002), end-of-treatment (EOT) visit (TARGET), or both EOT and post-treatment Day 70 visits (ERADICATE).ResultsIn the BPR-PIP-002 trial, five patients (all ceftobiprole treated) had a documented negative DAT result at baseline followed by a positive result at the TOC visit. One patient in the ongoing, blinded ERADICATE trial had a positive DAT result at both baseline and EOT. Results from other laboratory investigations showed no evidence of hemolytic anemia in these patients. No positive DAT results were reported in the TARGET trial.ConclusionNo evidence of hemolytic anemia associated with ceftobiprole was observed in either adults or children across several indications in this analysis of three large Phase 3 trials.

Management of acute bacterial skin and skin structure infections in India: are we equipped to meet the challenges of the growing menace of methicillin-resistant Staphylococcus aureus?

Staphylococcus aureus (S. aureus) is a Gram-positive facultative anaerobic bacterium that colonizes the skin and nasal passages of humans. The incidence of invasive S. aureus infections has increased over the past decades and is associated with poor outcomes and high mortality rates. S. aureus is responsible for almost one-third of acute bacterial skin and skin structure infections with methicillin-resistant Staphylococcus aureus (MRSA) accounting for a large proportion of these. The S. aureus strains prevalent inIndia are more aggressive and there are recent reports of the emergence of the more virulent multidrug resistant lineages ST2371 and ST8. Management of these infections is complicated by the fact that antimicrobial stewardship is non-existent, the choice of treatment is often empirical and available treatment options are limited due to a high prevalence of resistance strains. Currently available anti-MRSA agents include vancomycin, teicoplanin, linezolid, daptomycin, tigecycline, and clindamycin. However, the emergence of resistant strains and several undesirable features related to the safety and tolerability of these agents have limited the options available for the management of MRSA infections. A newer, safe and efficacious antibiotic is thus an unmet need for the management of MRSA in patients with acute bacterial skin and skin structure infections. In this review we explore the current and future trends in the management of acute bacterial skin and skin structure infections highlighting the challenges in their management in India, and current progress in the development of some novel drugs for the management of MRSA infections.

Managing Bacterial Infections in the Era of COVID-19

Managing Bacterial Infections in the Era of COVID-19

Efficacy and safety of dalbavancin in the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and other infections in a real-life setting: data from an Italian observational multicentric study (DALBITA study)

ABSTRACT Objectives We evaluated the efficacy and safety of dalbavancin in ABSSSI and ‘other sites’ infections’ (OTA). Methods Observational study involving 11 Italian hospitals including patients that received ≥1 dose of dalbavancin in 2016–2019. The outcome was end-of-treatment efficacy and safety in ABSSSI and OTA in a real-life setting. Results 206 patients enrolled (males 50%, median age 62 [IQR 50–76] years), 60.2% ABSSSI, 39.8% OTA. 69.7% ABSSSI vs 90.7% OTA (p = 0.003) and 46.3% ABSSSI vs 37.2% OTA (p = 0.786) received previous and concomitant antibiotics, respectively. 82.5% reached clinical cure . Eleven (5.4%) patients had non-serious adverse events (AE). OTA patients showed longer hospitalization (13.5 days, 5.5–22 vs 3, 0–11.7; p<0.0001) and received longer previous (18 days, 9–30 vs 11, 7–19; p = 0.007)/concomitant antibiotic treatments (21 days, 14–52 vs 11, 8–14; p < 0.0001), compared to ABSSSI. ABSSSI and OTA showed similar efficacy (85.5% vs 75%, p = 0.459) and safety (no AE: 81.5% vs 64.3%, p = 0.258); efficacy was independent of previous/concomitant therapies. Conclusions Dalbavancin demonstrated a success rate of >80%, with similar efficacy/safety in ABSSSI and off-label indications. The preferential use of dalbavancin as second-line or combination therapy would seem to suggest the need for in-depth studies focused on its off-label use.

In Vitro Activity and Potency of the Novel Oxazolidinone Contezolid (MRX-I) Tested against Gram-Positive Clinical Isolates from the United States and Europe.

Contezolid, a new oxazolidinone antibacterial agent currently in development for the treatment of skin and skin structure infections, was susceptibility tested against Gram-positive clinical isolates (n = 1,211). Contezolid demonstrated potent activity against Staphylococcus aureus (MIC50/90, 0.5/1 mg/liter), coagulase-negative Staphylococcus (MIC50/90, 0.25/0.5 mg/liter), Enterococcus spp. (MIC50/90, 0.5/1 mg/liter), and streptococci (MIC50/90, 1/1 mg/liter). Moreover, methicillin-resistant S. aureus and vancomycin-resistant Enterococcus faecium isolates were all inhibited by contezolid at ≤1 mg/liter. These results support the clinical development of contezolid.

Delafloxacin: A Review in Acute Bacterial Skin and Skin Structure Infections.

The global spread of antibacterial-resistant strains, especially methicillin-resistant Staphylococcus aureus (MRSA) for acute bacterial skin and skin structure infections (ABSSSIs), has driven the need for novel antibacterials. Delafloxacin [Quofenix™ (EU); Baxdela® (USA)], a new fluoroquinolone (FQ), has a unique chemical structure that enhances its antibacterial activity in acidic environments such as occurs in ABSSSIs (including S. aureus infections). Delafloxacin (intravenous and oral formulations) is approved in several countries for the treatment of adults with ABSSSIs (featured indication). In intent-to-treat analyses in pivotal phase 3 trials in adults with ABSSSIs, including those with comorbid disease, intravenous delafloxacin monotherapy (± oral switch after six doses) twice daily was noninferior to intravenous vancomycin + aztreonam for primary endpoints, as specified by the FDA (objective response rate at 48–78 h after initiation of therapy) and the EMA [investigator-assessed clinical cure rate at the follow-up visit at day 14 (± 1 day)]. Delafloxacin was generally well tolerated, with most treatment-related adverse events mild to moderate in severity and few patients discontinuing treatment because of these events. Relative to vancomycin + aztreonam (a non-FQ regimen), delafloxacin treatment was not associated with an increased risk of FQ-associated AEs of special interest. Given its unique chemical structure that confers novel properties relative to other FQ and its broad spectrum of activity against common clinically relevant Gram-positive pathogens, including against MRSA strains (± FQ-resistance mutations), and Gram-negative pathogens, intravenous delafloxacin (± oral switch) provides a novel emerging option for the treatment of adult patients with ABSSSIs.

Prevalence and predictors of oral to intravenous antibiotic switch among adult emergency department patients with acute bacterial skin and skin structure infections: a pilot, prospective cohort study

ObjectiveTo determine the prevalence and predictors of oral to intravenous antibiotic switch among adult emergency department (ED) patients with acute bacterial skin and skin structure infections (ABSSSIs).DesignMulticentre, pilot cohort study.SettingThree...

Effect of Vancomycin-Associated Acute Kidney Injury on Incidence of 30-Day Readmissions among Hospitalized Veterans Affairs Patients with Skin and Skin Structure Infections.

Among hospitalized adults who received vancomycin for their skin and skin structure infection (SSSI), patients who experienced acute kidney injury (AKI) had considerably higher 30-day readmission rates. Nearly half of the observed 30-day readmissions were due to non-SSSI-related reasons, which is consistent with the persistent organ dysfunction observed among patients with AKI.

Structure-Activity Relationships of Daptomycin Lipopeptides.

Daptomycin is a calcium-dependent cyclic lipodepsipeptide derived from the soil saprotroph Streptomyces roseosporus, and its antibiotic properties make it a key agent for treatment of drug-resistant Gram-positive infections. It is most commonly used clinically for the treatment of Gram-positive skin and skin structure infections (SSSI), Staphylococcus aureus bacteremia, and right-sided endocarditis infections associated with S. aureus, including methicillin resistant S. aureus (MRSA). It has also been used "off-label" for Enterococcal infections. There has been a tremendous amount of research investigating its mode of action, resistance mechanisms, and biosynthesis of this clinically important antimicrobial agent. Although we cover the latter aspects in detail, the primary focus of this review is to provide the most comprehensive and up-to-date reference for the medicinal chemist on the structure-activity-toxicity of this important class of lipopeptide antibiotics.

Assessment of Antibacterial Activity of Levonadifloxacin against Contemporary Gram-positive Clinical Isolates Collected from Various Indian Hospitals using Disk-Diffusion Assay

AbstractObjectives: Levonadifloxacin is a novel benzoquinolizine subclass of quinolone with broad-spectrum activities against problematic pathogens such as methicillin-resistant Staphylococcus aureus, quinolone-resistant S. aureus, vancomycin intermediate S. aureus, and vancomycin-resistant S. aureus. Levonadifloxacin and its oral prodrug, alalevonadifloxacin, have been recently approved in India for the treatment of acute bacterial skin and skin structure infections, including concurrent bacteraemia and diabetic foot infections. The aim of the study is to assess the activity of levonadifloxacin against Gram-positive clinical isolates collected from various Indian hospitals using the disc-diffusion method. Materials and Methods: Nonduplicate isolates of S. aureus and other Gram-positive isolates collected from June 2019 to March 2020 were subjected to levonadifloxacin susceptibility testing (disk diffusion method) as per the Clinical and Laboratory Standards Institute guidelines (Year 2019). Levonadifloxacin 10 μg impregnated disks were used during the testing. Results: A total of 664 diverse Gram-positive clinical isolates collected from six different hospitals in India were analyzed. Majority (65.5%) of the isolates were S. aureus. All the S. aureus and other Gram-positive isolates were found to be susceptible to levonadifloxacin as per the prespecified interpretive criteria identified based on population pharmacokinetic model and Monte Carlo simulation enabled probability of pharmacodynamic target attainment analysis. Conclusions: The present study showed that levonadifloxacin was highly active against contemporary Gram-positive pathogens and furthermore demonstrated that levonadifloxacin susceptibilities can be reliably determined using the disc-diffusion method.

Population Pharmacokinetic Analyses for Omadacycline Using Phase 1 and 3 Data.

Omadacycline, a novel aminomethylcycline antibiotic with activity against Gram-positive and -negative organisms, including tetracycline-resistant pathogens, received FDA approval in October 2018 for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP). A previously developed population pharmacokinetic (PK) model based on phase 1 intravenous and oral PK data was refined using data from infected patients. Data from 10 phase 1 studies used to develop the previous model were pooled with data from three additional phase 1 studies, a phase 1b uncomplicated urinary tract infection study, one phase 3 CABP study, and two phase 3 ABSSSI studies. The final population PK model was a three-compartment model with first-order absorption using transit compartments to account for absorption delay following oral dosing and first-order elimination. Epithelial lining fluid (ELF) concentrations were modeled as a subcompartment of the first peripheral compartment. A food effect on oral bioavailability was included in the model. Sex was the only significant covariate identified, with 15.6% lower clearance for females than males. Goodness-of-fit diagnostics indicated a precise and unbiased fit to the data. The final model, which was robust in its ability to predict plasma and ELF exposures following omadacycline administration, was also able to predict the central tendency and variability in concentration-time profiles using an external phase 3 ABSSSI data set. A population PK model, which described omadacycline PK in healthy subjects and infected patients, was developed and subsequently used to support pharmacokinetic-pharmacodynamic (PK-PD) and PK-PD target attainment assessments.

Delafloxacin activity against Staphylococcus aureus with reduced susceptibility or resistance to methicillin, vancomycin, daptomycin or linezolid.

Delafloxacin is a recently approved anionic fluoroquinolone antibiotic with broad-spectrum activity against Gram-positive and Gram-negative organisms. The drug has been approved for patients with acute bacterial skin and skin structure infections including those caused by MRSA. There are limited data available against MRSA blood isolates (MRSABIs), vancomycin-intermediate strains (VISA), vancomycin-resistant strains (VRSA), daptomycin-non-susceptible strains (DNSSA) and linezolid-resistant Staphylococcus aureus (LRSA). Antimicrobial activity of delafloxacin, levofloxacin, vancomycin, daptomycin and linezolid was determined against 110 MRSABIs, 15 VRSA, 35 VISA, 40 DNSSA and 6 LRSA. Microdilution testing using CAMHB was used to determine MIC according to CLSI guidelines. FDA breakpoints were used to determine delafloxacin susceptibility, and CLSI breakpoints were used for all other antibiotics. PCR testing for molecular markers was performed. Delafloxacin demonstrated activity against MRSABIs with an MIC90 of 1 mg/L and 68% susceptibility. Against the other groups the MIC90 and susceptibility were 1 mg/L and 40%, respectively, for VISA, 4 mg/L and 7% for VRSA and 1 mg/L and 38% for DNSSA. None of the LRSA isolates was susceptible to delafloxacin. Delafloxacin was active against 94% of MRSA blood isolates that were genotype SCC IVa. For MRSABIs with a levofloxacin MIC ≥8 mg/L (55/110), suggesting multiple mutations in the QRDR, delafloxacin MIC90 was 1 mg/L with a 36.4% susceptibility rate. Delafloxacin demonstrates superior activity to levofloxacin against recent MRSA blood isolates, VISA, VRSA and DNSSA, and demonstrates good activity against blood isolates most commonly found in the community.

Tedizolid (torezolid) for the treatment of complicated skin and skin structure infections

ABSTRACT Introduction Acute bacterial skin and skin structure infections (ABSSSI) are among the most frequent infectious diseases. Recently, several new antibiotics with activity against MRSA have been approved. Tedizolid, a second-generation oxazolidinone approved for ABSSSI offers theoretical advantages over first-generation oxazolidinones. Areas covered A comprehensive online search of Medline, ClinicalTrials.gov, and conference presentations was made, selecting articles between January 2000 and April 2020. In this review, the authors discuss the chemical and microbiological properties of tedizolid, summarize its efficacy, safety, and potential role in the treatment of ABSSSI as well as the potential for future indications. Expert opinion Tedizolid has proven to be non-inferior compared to linezolid for the treatment of ABSSSI in two registrational phase III clinical trials, being well tolerated. Tedizolid exhibits antibacterial activity against the most important ABSSSI pathogens (including multidrug-resistant strains of MRSA), as well as mycobacteria and Nocardia. It appears to have a safe profile, including decreased myelotoxicity and no significant drug interactions. Preliminary studies with longer duration of therapy seem to confirm these potential benefits. Overall, tedizolid expands the newly acquired armamentarium to treat ABSSSI. The role of tedizolid for other indications is under investigation and has yet to be determined.

Treatment of Acute Osteomyelitis with Once-Weekly Oritavancin: A Two-Year, Multicenter, Retrospective Study.

BackgroundAcute osteomyelitis is typically caused by Gram-positive pathogens, commonly antibiotic-resistant Staphylococcus species. Standard antibiotic treatment is challenging due to required multiple daily doses, therapeutic drug monitoring, and parenteral administration for at least 4 weeks. Oritavancin is a long-acting lipoglycopeptide antibiotic approved as a single 1200 mg dose for the treatment of adult patients with acute bacterial skin and skin structure infections.ObjectiveTo characterize the real-world use, efficacy, and safety of oritavancin in adult patients with acute osteomyelitis.MethodsThis was a 2-year, multicenter, retrospective, descriptive study of patients treated for acute osteomyelitis with weekly doses of oritavancin. End of therapy evaluation (ETE) was defined as evaluation at 7–10 days after the last dose of oritavancin, and post-therapy assessment (PTE) was at 3 months and 6 months. At ETE and PTE, patients were interviewed via telephone for clinical outcomes, using a standard questionnaire. Electronic medical record review was also conducted.Results134 patients were treated with oritavancin for acute osteomyelitis across 20 different Metro Infectious Disease Consultants infusion centers in six states. Of total positive cultures, 71.9% (92/128) were methicillin-resistant Staphylococcus aureus (MRSA) from deep wounds, bone, or joint culture; an additional nine (6.7%) of 134 patients presented with concomitant MRSA bacteremia. Oritavancin was administered via intravenous catheter; patients received an initial treatment of 1200 mg and then 800 mg weekly thereafter for a total number of doses of four (n = 118) or five (n = 16). 118 patients (88.1%) of the baseline 134 patients achieved clinical success at the ETE timepoint. 130 patients were available for PTE at 3 months and 6 months. Overall, relapse or persistent infection was diagnosed in 13/134 (9.7%) patients. Nine (6.7%) of 134 patients were admitted to the hospital during the follow-up period but none for osteomyelitis. Adverse events were reported in five (3.7%) patients including hypoglycemia-related symptoms (three patients), tachycardia (one patient), and tachycardia with chest pain (one patient). None of these patients were hospitalized due to adverse events, and all patients eventually finished their treatment regimens.ConclusionThis is the largest real-world clinical study of adult patients treated with oritavancin for acute osteomyelitis. Use of oritavancin for acute osteomyelitis infection resulted in a high rate of positive clinical outcomes and a low incidence of adverse events, thereby providing potential for a convenient, effective, and safe therapeutic option. Future prospective and comparative studies are needed to validate these findings.

The Real-World Economic and Clinical Management of Adult Patients with Skin and Soft Tissue Infections (SSTIs) with Oritavancin: Data from Two Multicenter Observational Cohort Studies.

BackgroundOritavancin is a FDA-approved single-dose IV therapy for the treatment of acute bacterial skin and skin structure infections caused (or suspected to be caused) by certain Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Published data describing the outcomes of patients with skin and soft tissue infections (SSTIs) who received oritavancin beyond its pivotal phase III clinical trials are scant.ObjectiveThe purpose of this report was to describe the results of two separate multicenter observational cohort studies that described the outcomes associated with two unique real-world usage patterns of oritavancin.MethodsThe first cohort (n = 115) examined patients 18 years or older who were treated with oritavancin at three outpatient sites for SSTIs caused by suspected or confirmed Gram-positive pathogens, including MRSA, to avoid hospital admission. Patients were included if they had not been discharged from the inpatient setting within the previous 24 h and received their single-dose oritavancin treatment at a hospital-based outpatient infusion center. The primary outcomes measured were 30-day healthcare costs and admissions (all cause and infection related). The second cohort (n = 151) was a multicenter, retrospective chart review of adult patients who were discharged early from seven hospitals in 2015 on oritavancin for SSTIs. The primary outcome was readmission of patients within 30 days (all cause and infection related).ResultsIn cohort 1, 30-day mean healthcare costs were USD 3698. In the study of patients who started oritavancin in the outpatient setting, 7 patients (6.1%) were admitted to hospital within 30 days of the index treatment, and 3 of those (2.6% overall) were deemed to be due to an infection. In cohort 2, all-cause and infection-related 30-day readmission rates were 6.6% and 2.6%, respectively, among patients who received oritavancin at hospital discharge.ConclusionsFindings from these studies suggest that oritavancin may be a potentially useful agent to avoid hospitalization or shorten hospital length of stay among appropriate SSTI patients. Future comparator studies are required to properly ascertain the outcomes and potential benefits associated with oritavancin relative to other commonly used antibiotics in patients with SSTIs.

Early Directed Oritavancin Therapy in the Emergency Department May Lead to Hospital Avoidance Compared to Standard Treatment for Acute Bacterial Skin and Skin Structure Infections: A Real-World Retrospective Analysis

ObjectivesAcute bacterial skin and soft tissue infections (ABSSSIs) are a leading cause of presentation to the emergency department (ED). This study aimed to determine the potential impact of utilizing oritavancin in the ED or observation unit (OBS) on hospital inpatient admission.MethodsA single-center community teaching hospital developed a pharmacy-led pilot to evaluate the use of oritavancin as a measure to avoid hospital admissions/readmissions in appropriate patients with ABSSSIs. Prior to initiation of the oritavancin pilot, prespecified inclusion and exclusion criteria were determined for proper patient selection. The pilot ran from January 1 to December 31, 2017. The data were compared to corresponding data for an equal number of patients during the pilot period who had similar ABSSSI diagnoses to the oritavancin pilot group but received vancomycin. The primary outcome was length of stay (LOS), defined as the total time in hours from presentation to the ED until discharge home, including time spent in the OBS or inpatient unit.ResultsDuring the study period, 122 patients met the study criteria and 61 patients received oritavancin in the ED or OBS unit. These patients were compared to 61 consecutive patients during the pilot period who received vancomycin. Administration of oritavancin in the ED or OBS was associated with a significantly shorter mean LOS relative to the standard of care group (19.5 vs. 85.98 h, p < 0.01). All-cause 30-day readmissions were the same for both groups (6 vs. 6, p = 1).ConclusionsThese results suggest that use of oritavancin in the ED or OBS setting for ABSSSIs may shorten LOS without negatively affecting readmissions.

Clinical Outcomes and Economic Impact of Oritavancin for Gram-Positive Infections: A Single Academic Medical Center Health System Experience.

BackgroundVancomycin treatment of complicated Gram-positive infections is associated with laboratory monitoring, nephrotoxicity, and multiple daily dosing. Oritavancin, a lipoglycopeptide antibiotic with a once-weekly dosing strategy and similar but slightly broader spectrum of activity, presents several opportunities over vancomycin to improve compliance and convenience for the patient. Minimal real-world clinical and acquisition cost data in the inpatient setting and clinical data surrounding multiple dosing in the outpatient setting have limited oritavancin use despite its potential logistic advantages.ObjectivesWe describe inpatient and outpatient oritavancin administration, clinical outcomes, and economic impact.MethodsThis was a single-center, retrospective case series of patients treated with at least one dose of oritavancin between May 2015 and September 2017 at an academic medical center in the USA. A simplified cost-avoidance analysis was conducted assuming the patient had a national health insurance plan and focused on hospital days prevented.ResultsSeventy-five patients received oritavancin during the study period. The most common use of oritavancin was in patients with acute bacterial skin and skin structure infections (ABSSSI), defined as cellulitis, abscess or non-surgical wounds (n = 25, 33%), followed by surgical wound infections (n = 12, 16%) and osteomyelitis or septic arthritis (n = 10, 13%). Clinical cure or improvement was achieved in 68 patients (93.2%), while five patients (6.8%) failed treatment; adverse reactions were reported in nine patients (12%). Thirty-five patients received oritavancin as inpatients; 20 patients (57%) had at least one hospital day avoided due to inpatient oritavancin administration resulting in a total cost avoidance of US$343,654.ConclusionIn this series of 75 patients with Gram-positive infections, oritavancin treatment resulted in clinical cure or improvement in most patients, and was generally well tolerated. Inpatient administration may avoid costs and outpatient administration is a reasonable consideration for patients in which prolonged antibiotic therapy is necessary.

Dalbavancin for the management of osteomyelitis: a major step forward?

Osteomyelitis is one of the most challenging infectious diseases to treat and is associated with a significant burden to healthcare systems. There are limited available therapeutic options to treat osteomyelitis caused by Gram-positive pathogens and these are not without limitations. Dalbavancin is a long-acting lipoglycopeptide, approved for the treatment of acute bacterial skin and skin structure infections caused by designated susceptible strains of Gram-positive microorganisms. It demonstrated promising pharmacokinetic/pharmacodynamic properties and safety data to be considered for the treatment of bone infections. However, information on the effectiveness and safety of dalbavancin in the treatment of invasive Gram-positive infections, such as osteomyelitis, is very limited. In this review, we describe the novel characteristics and potential utility of dalbavancin in the treatment of osteomyelitis and summarize its long-term clinical outcomes from published case reports, series and comparative studies.

Ceftobiprole Activity against Bacteria from Skin and Skin Structure Infections in the United States from 2016 through 2018.

Ceftobiprole medocaril is an advanced-generation cephalosporin prodrug that has qualified infectious disease product status granted by the US FDA and is currently being evaluated in phase 3 clinical trials in patients with acute bacterial skin and skin structure infections (ABSSSIs) and in patients with Staphylococcus aureus bacteremia. In this study, the activity of ceftobiprole and comparators was evaluated against more than 7,300 clinical isolates collected in the United States from 2016 through 2018 from patients with skin and skin structure infections. The major species/pathogen groups were S. aureus (53%), Enterobacterales (23%), Pseudomonas aeruginosa (7%), beta-hemolytic streptococci (6%), Enterococcus spp. (4%), and coagulase-negative staphylococci (2%). Ceftobiprole was highly active against S. aureus (MIC50/90, 0.5/1 mg/liter; 99.7% susceptible by EUCAST criteria; 42% methicillin-resistant S. aureus [MRSA]). Ceftobiprole also exhibited potent activity against other Gram-positive cocci. The overall susceptibility of Enterobacterales to ceftobiprole was 84.8% (>99.0% susceptible for isolate subsets that exhibited a non-extended-spectrum β-lactamase [ESBL] phenotype). A total of 74.4% of P. aeruginosa, 100% of beta-hemolytic streptococci and coagulase-negative staphylococci, and 99.6% of Enterococcus faecalis isolates were inhibited by ceftobiprole at ≤4 mg/liter. As expected, ceftobiprole was largely inactive against Enterobacterales that contained ESBL genes and Enterococcus faecium Overall, ceftobiprole was highly active against most clinical isolates from the major Gram-positive and Gram-negative skin and skin structure pathogen groups collected at U.S. medical centers participating in the SENTRY Antimicrobial Surveillance Program during 2016 to 2018. The broad-spectrum activity of ceftobiprole, including potent activity against MRSA, supports its further evaluation for a potential ABSSSI indication.

In vitro activity of omadacycline and levofloxacin against Escherichia coli, Klebsiella pneumoniae and Staphylococcus saprophyticus in human urine supplemented with calcium and magnesium.

BackgroundOmadacycline, an aminomethylcycline, was approved in 2018 for the treatment of acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia. In a Phase Ib study, around 34% of the absorbed dose of omadacycline was shown to be excreted in urine—an important property for urinary tract infection (UTI) treatment. Therefore, omadacycline has been studied in two Phase II trials for the treatment of uncomplicated UTIs and acute pyelonephritis. The activity of omadacycline against UTI pathogens in human urine is important to understand in this context.ObjectivesTo study the in vitro activity of omadacycline against UTI pathogens in human urine supplemented with calcium and magnesium.MethodsOmadacycline activity was compared with that of levofloxacin against the urinary pathogens Escherichia coli, Klebsiella pneumoniae and Staphylococcus saprophyticus in standard medium, pooled normal human urine and neutral pH-adjusted pooled normal human urine spiked with calcium or magnesium at concentrations consistent with hypercalcaemia and hypermagnesaemia.ResultsThe activities of omadacycline and levofloxacin against these urinary pathogens were lower in urine relative to standard medium; addition of Mg2+ to broth and urine had a further negative impact on omadacycline activity, whereas the addition of Ca2+ had less of an impact. Levofloxacin activity was not substantially reduced in either broth or urine by the addition of divalent cations.ConclusionsThe activity of omadacycline against UTI organisms was lower in urine relative to standard medium and was negatively impacted by magnesium. Omadacycline displayed slightly reduced activity when excess calcium was present, but, overall, the differences were ≤2-fold. These observations should be considered along with the pharmacokinetics of the agent for clinical context.