Antimicrobial Activity of Ceftaroline Tested against Staphylococcus aureus from Surgical Skin and Skin Structure Infections in US Medical Centers

Optimization of fermentation parameters to improve the biosynthesis of selenium nanoparticles by Bacillus licheniformis F1 and its comprehensive application

BACKGROUND

Selenium nanoparticles (SeNPs) are increasingly gaining attention due to its characteristics of low toxicity, high activity, and stability. Additionally, Bacillus licheniformis, as a probiotic, has achieved remarkable research outcomes in diverse fields such as medicine, feed processing, and pesticides, attracting widespread attention. Consequently, evaluating the activity of probiotics and SeNPs is paramount. The utilization of probiotics to synthesize SeNPs, achieving large-scale industrialization, is a current hotspot in the field of SeNPs synthesis and is currently the most promising synthetic method. To minimize production costs and maximize yield of SeNPs, this study selected agricultural by-products that are nutrient-rich, cost-effective, and readily available as culture medium components. This approach not only fulfills industrial production requirements but also mitigates the impact on downstream processes.

RESULTS

The experimental findings revealed that SeNPs synthesized by B. licheniformis F1 exhibited a spherical morphology with diameters ranging from 110 to 170 nm and demonstrating high stability. Both the secondary metabolites of B. licheniformis F1 and the synthesized SeNPs possessed significant free radical scavenging ability. To provide a more robust foundation for acquiring large quantities of SeNPs via fermentation with B. licheniformis F1, key factors were identified through single-factor experiments and response surface methodology (RSM) include a 2% seed liquid inoculum, a temperature of 37 ℃, and agitation at 180 rpm. Additionally, critical factors during the optimization process were corn powder (11.18 g/L), soybean meal (10.34 g/L), and NaCl (10.68 g/L). Upon validating the optimized conditions and culture medium, B. licheniformis F1 can synthesize nearly 100.00% SeNPs from 5 mmol/L sodium selenite. Subsequently, pilot-scale verification in a 5 L fermentor using the optimized medium resulted in a shortened fermentation time, significantly reducing production costs.

CONCLUSION

In this study, the efficient production of SeNPs by the probiotic B. licheniformis F1 was successfully achieved, leading to a significant reduction in fermentation costs. The exploration of the practical applications of this strain holds significant potential and provides valuable guidance for facilitating the industrial-scale implementation of microbial synthesis of SeNPs.

Anti-MRSA Cephalosporin versus Vancomycin-Based Treatment for Acute Bacterial Skin and Skin Structure Infection: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) compared the clinical efficacy and safety of anti-MRSA cephalosporin and vancomycin-based treatment in treating acute bacterial skin and skin structure infections (ABSSSIs). PubMed, Embase, Cochrane Central Register of Controlled Trials, Turning Research into Practice, and ClinicalTrials.gov databases were searched for relevant articles from inception to 15 June 2020. RCTs comparing the clinical efficacy and safety of anti-MRSA cephalosporin with those of vancomycin-based regimens in treating adult patients with ABSSSIs were included. The primary and secondary outcomes were clinical response at the test-of-cure assessments and risk of adverse events (AEs), respectively. Eight RCTs were enrolled. The clinical response rate was not significantly different between anti-MRSA cephalosporin and vancomycin-based treatments (odds ratio [OR], 1.05; 95% CI, 0.90–1.23; I² = 0%). Except for major cutaneous abscesses in which anti-MRSA cephalosporin-based treatment was associated with a lower clinical response rate than vancomycin-based treatment (OR, 0.62; 95% CI, 0.40–0.97; I² = 0%), other subgroup analyses according to the type of cephalosporin (ceftaroline or ceftobiprole), type of infection, and different pathogens did not show significant differences in clinical response. Anti-MRSA cephalosporin-based treatment was only associated with a higher risk of nausea than vancomycin-based treatment (OR, 1.41; 95% CI, 1.07–1.85; I² = 0%). In treating ABSSSIs, the clinical efficacy of anti-MRSA cephalosporin is comparable to that of vancomycin-based treatment, except in major cutaneous abscesses. In addition to nausea, anti-MRSA cephalosporin was as tolerable as vancomycin-based treatment.

Prevalence and molecular epidemiology of ceftaroline non-susceptible methicillin-resistant Staphylococcus aureus isolates, first clinical report from Iran

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens in Iran with a high prevalence and a high level of antibiotic resistance. Ceftaroline is a fifth generation cephalosporin binding and inhibiting penicillin binding protein (PBP2a).

METHODS

In the present study, 228 clinical MRSA isolates were collected from four cities of Iran and their susceptibility to ceftaroline was evaluated by E-test and the disk diffusion method.

RESULTS

Our results showed a high susceptibility rate (97.3%) to ceftaroline in MRSA strains from Iran. Six isolates were found to be ceftaroline non-susceptible (CPT-NS) with Minimum inhibitory concentration (MIC) ≥2 µg/mL. All CPT-NS isolates were isolated from blood and tracheal aspirate and belonged to SCCmec type III as well as agr type I and were all susceptible to vancomycin. Out of six isolates, three, two and one belonged to spa type t030, t4864, and t969, respectively. Vancomycin, quinupristin/dalfopristin, linezolid, chloramphenicol, and tigecycline were the most active agents against CPT-NS isolates.

CONCLUSION

Due to the broad-spectrum activity and low toxicity of ceftaroline as well as the increased rate of vancomycin resistance among MRSA strains in recent years, ceftaroline can be considered as a novel approach to treat MRSA-induced infections.

Update on the activity of delafloxacin against acute bacterial skin and skin-structure infection isolates from European hospitals (2014-2019)

OBJECTIVES

Delafloxacin is a broad-spectrum anionic fluoroquinolone with activity against Gram-positive and Gram-negative organisms, including methicillin-resistant Staphylococcus aureus. Both oral and intravenous formulations were approved for use in the treatment of acute bacterial skin and skin-structure infections (ABSSSIs) due to Gram-positive and Gram-negative organisms by the US Food and Drug Administration (2017) and European Medicines Agency (2019), and for community-acquired bacterial pneumonia by the FDA (2019). The SENTRY Antimicrobial Surveillance Program has monitored the susceptibility of delafloxacin in the USA and Europe since 2014. The purpose of this study is to provide an update on delafloxacin activity against ABSSSI isolates primarily collected from hospitalised patients in Europe.

METHODS

A total of 11,866 non-duplicate ABSSSI isolates were collected from 2014 to 2019 from 46 European medical centres in 24 countries. Susceptibilities were determined by broth microdilution. Results were interpreted using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (2020).

RESULTS

The most common isolate wasS. aureus (37.8%; n = 4484), followed by Escherichia coli (11.0%) and Streptococcus spp. (10.0%). Delafloxacin susceptibility for S. aureus was 92.4% (MIC_50/90, ≤0.004/0.25 mg/L), streptococci 98.4% and E. coli 58.1%. Delafloxacin was more active against S. aureus than levofloxacin (84.0% intermediate; MIC_50/90, 0.25/>4 mg/L) and moxifloxacin (84.3% susceptible; MIC_50/90, ≤0.06/2 mg/L). Susceptibility of E. coli was similar for the three quinolones.

CONCLUSIONS

Delafloxacin had broad-spectrum activity and improved potency against Gram-positive pathogens compared with levofloxacin and moxifloxacin. These data suggest that delafloxacin may be a useful therapeutic choice for the most common causes of ABSSSI.

Evaluating the antibacterial activity of ceftaroline against clinical isolates of methicillin-susceptible and- resistant Staphylococcus aureus in Kuwait hospitals

Ceftaroline fosamil has been approved by the US Food and Drug Administration for the treatment of skin and soft tissue infections, including those caused by methicillin-resistant Staphylococcus aureus and community-acquired bacterial pneumonia. We evaluated the in-vitro activity of not-in-use ceftaroline against clinical isolates of methicillin- resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus isolates. A total of 453 single-patient S. aureus isolates were tested for susceptibility to ceftaroline. The minimum inhibitory concentration (MIC) was determined using the MIC Evaluator. Disk diffusion test was performed using 30 μg ceftaroline disk according to the Clinical Laboratory Standards Institute criteria. In total, 410 (90.5%) of the 453 strains were susceptible to ceftaroline at MIC of 1 mg/L while 9.8% isolates had MIC of 2-3 mg/L. Among the MSSA, 92.5% of the isolates were susceptible with MIC: 1 mg/L while 36 (7.9%) strains expressed intermediate resistance (MIC range of 2-3 mg/L). None of the strains was resistant (MIC: 4 mg/L). Ceftaroline showed good in-vitro activity against MSSA and MRSA which can serve as an effective alternative to vancomycin in treating infections caused by MRSA.

Ceftaroline Efficacy and Safety in Treatment of Complicated Skin and Soft Tissue Infection: A Systemic Review and Meta-Analysis of Randomized Controlled Trials

This study aims to assess the clinical efficacy and safety of ceftaroline for the treatment of complicated skin and skin structure infections (cSSSIs) in adult patients through meta-analysis. PubMed, Embase, ClinicalTrials.gov, and Cochrane databases were searched up to April 2019. Only randomized controlled trials (RCTs) that evaluated ceftaroline and other comparators for treating cSSSIs in adult patients were included. The primary outcome was the clinical cure rate, whereas the secondary outcomes were clinical failure rate, microbiological eradication rate, relapse rate, and risk of an adverse event (AE). Five RCTs were included. Overall, ceftaroline had a clinical cure rate similar to comparators in the treatment of cSSSIs in the modified intent-to-treat population (risk ratio (RR), 1.00; 95% confidence interval (CI), 0.97–1.04; I² = 0%) and in the clinically evaluable population (RR, 1.00; 95% CI, 0.97–1.03; I² = 0%). In addition, no significant difference was observed between ceftaroline and comparators for the treatment of infection with Staphylococcusaureus (RR, 1.01; 95% CI, 0.98–1.05; I² = 0%), methicillin-resistant S. aureus (RR, 0.99; 95% CI, 0.94–1.05; I² = 0%), methicillin-susceptible S. aureus (RR, 1.01; 95% CI, 0.96–1.06; I² = 26%), Streptococcus spp. (RR, 1.07; 95% CI, 0.92–1.24; I² = 73%), and Gram-negative bacteria (RR, 0.94; 95% CI, 0.83–1.08; I² = 0%). Furthermore, ceftaroline had a similar rate of microbiological eradication (92.2% vs. 92.6%, RR, 1.00; 95% CI, 0.97–1.03; I² = 9%) and relapse (6.9% vs. 9.1%, RR, 0.48; 95% CI, 0.14–1.74; I² = 0%) as comparators. Finally, the risks of treatment-emergent AEs (RR, 0.96; 95% CI, 0.88–1.05; I² = 0%), serious AEs (RR, 1.03; 95% CI, 0.63–1.68; I² = 0%), and discontinuation of study drug due to an AE (RR, 0.86; 95% CI, 0.50–1.49; I² = 34%) did not differ significantly between ceftaroline and comparators. In conclusion, the clinical efficacy of ceftaroline is as high as that of comparators in the treatment of cSSSIs in adult patients, and this antibiotic is well tolerated like the comparators.

In Vitro Activity of the Novel Lactone Ketolide Nafithromycin (WCK 4873) against Contemporary Clinical Bacteria from a Global Surveillance Program

Nafithromycin (WCK 4873), a novel antimicrobial agent of the lactone ketolide class, is currently in phase 2 development for treatment of community-acquired bacterial pneumonia (CABP). A total of 4,739 nonduplicate isolates were selected from a 2014 global surveillance program at medical institutions located in 43 countries within the United States, Europe, Latin America, and the Asia-Pacific region. Nafithromycin and comparator agents were used for susceptibility testing by reference broth microdilution methods. Nafithromycin was active against Staphylococcus aureus (MIC_50/90, 0.06/>2 μg/ml), including erythromycin-resistant strains exhibiting an inducible clindamycin resistance phenotype (MIC_50/90, 0.06/0.06 μg/ml) and telithromycin-susceptible strains (MIC_50/90, 0.06/0.06 μg/ml), but it exhibited limited activity against most telithromycin-resistant and clindamycin-resistant isolates that were constitutively resistant to macrolides (MIC_50/90, >2/>2 μg/ml). Nafithromycin was very active (MIC_50/90, 0.015/0.06 μg/ml) against 1,911 Streptococcus pneumoniae strains, inhibiting all strains, with MIC values of ≤0.25 μg/ml. Telithromycin susceptibility was 99.9% for Streptococcus pneumoniae strains, and nafithromycin was up to 8-fold more potent than telithromycin. Overall, 37.9% of S. pneumoniae strains were resistant to erythromycin, and 19.7% were resistant to clindamycin. Nafithromycin was highly active against 606 Streptococcus pyogenes strains (MIC_50/90, 0.015/0.015 μg/ml), inhibiting 100.0% of isolates at ≤0.5 μg/ml, and MIC_50/90 values (0.015/0.015 to 0.03 μg/ml) were similar for the 4 geographic regions. Nafithromycin and telithromycin demonstrated comparable in vitro activities against 1,002 Haemophilus influenzae isolates and 504 Moraxella catarrhalis isolates. Overall, nafithromycin showed potent in vitro activity against a broad range of contemporary (2014) global pathogens. These results support the continued clinical development of nafithromycin for treatment of CABP.

Antimicrobial Susceptibility Trends among Staphylococcus aureus Isolates from U.S. Hospitals: Results from 7 Years of the Ceftaroline (AWARE) Surveillance Program, 2010 to 2016

We evaluated trends in Staphylococcus aureus antimicrobial susceptibility in U.S. hospitals in the 2010-2016 period. A total of 21,056 clinical isolates from 42 medical centers were tested for susceptibility by broth microdilution methods. Methicillin-resistant S. aureus (MRSA) rates decreased from 50.0% (in 2010) to 42.2% (in 2016). Susceptibility to erythromycin, levofloxacin, and clindamycin increased slightly, whereas susceptibility to ceftaroline, trimethoprim-sulfamethoxazole, and tetracycline remained stable. Ceftaroline retained potent activity against methicillin-susceptible S. aureus (MSSA) and MRSA (97.2% susceptible) with no marked variations.

Dosing strategies to optimize currently available anti-MRSA treatment options (Part 1: IV options)

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a predominant pathogen resulting in significant morbidity and mortality. Optimal dosing of anti-MRSA agents is needed to help prevent the development of antimicrobial resistance and to increase the likelihood of a favorable clinical outcome. Areas covered: This review summarizes the available data for antimicrobials routinely used for MRSA infections that are not administered orally or topically. We make recommendations and highlight the current gaps in the literature. A PubMed (1966 - Present) search was performed to identify relevant literature for this review. Expert commentary: Improvements in MIC determination and therapeutic drug monitoring are needed to fully implement individualized dosing that optimizes antimicrobial pharmacodynamics.Additional data will become available for these agents in regards to effectiveness for severe MRSA infections and pharmacokinetic data for special patient populations.

Antimicrobial activity of ceftaroline against methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 2013-2014 at the Geneva University Hospitals

Ceftaroline is a broad-spectrum antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Ceftaroline susceptibility of an MRSA set archived between 1994 and 2003 in the Geneva University Hospitals detected a high percentage (66 %) of ceftaroline resistance in clonotypes ST228 and ST247 and correlated with mutations in PBP2a. The ceftaroline mechanism of action is based on the inhibition of PBP2a; thus, the identification of PBP2a mutations of recently circulating clonotypes in our institution was investigated. We analyzed ceftaroline susceptibility in MRSA isolates (2013 and 2014) and established that resistant strains correlated with PBP2a mutations and specific clonotypes. Ninety-six MRSA strains were analyzed from independent patients and were isolated from blood cultures (23 %), deep infections (38.5 %), and superficial (skin or wound) infections (38.5 %). This sample showed a ceftaroline minimum inhibitory concentration (MIC) range between 0.25 and 2 μg/ml and disk diameters ranging from 10 to 30 mm, with a majority of strains showing diameters ≥20 mm. Based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, 76 % (73/96) of isolates showed susceptibility to ceftaroline. Nevertheless, we still observed 24 % (23/96) of resistant isolates (MIC = 2 μg/ml). All resistant isolates were assigned to clonotype ST228 and carried the N146K mutation in PBP2a. Only two ST228 isolates showed ceftaroline susceptibility. The decreasing percentage of ceftaroline-resistant isolates in our hospital can be explained by the decline of ST228 clonotype circulating in our hospital since 2008. We present evidence that ceftaroline is active against recent MRSA strains from our hospital; however, the presence of PBP2a variants in particular clonotypes may affect ceftaroline efficacy.

Antimicrobial susceptibility patterns of community- and hospital-acquired methicillin-resistant Staphylococcus aureus from United States Hospitals: results from the AWARE Ceftaroline Surveillance Program (2012-2014)

Among 8437 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from 143 medical centers in the United States (2012-2014), 7116 and 1321 were reported as community-acquired (CA) and hospital-acquired (HA) MRSA, respectively. CA-/HA-MRSA were most often isolated from patients with skin and skin structure infections (SSSI; 68.4/26.9%), pneumonia (13.7/49.0%) and bacteremia (10.0/17.7%). Overall, susceptibility rates were generally lower among HA-MRSA compared to CA-MRSA strains, especially for clindamycin (44.6 vs. 66.1%) and levofloxacin (21.4 vs. 35.5%). Also, susceptibility rates were lower for these two compounds among isolates from pneumonia compared to SSSI and bacteremia. Ceftaroline was broadly active against 98.0% of CA-MRSA and 94.3% of HA-MRSA (MIC50/90, 1μg/mL for both; no resistant isolate) overall, with little variation among infection type subsets.