In vivo emergence of ceftaroline resistance during therapy for MRSA vertebral osteomyelitis

Antibiotic Resistance to Molecules Commonly Prescribed for the Treatment of Antibiotic-Resistant Gram-Positive Pathogens: What Is Relevant for the Clinician?

Antibiotic resistance in Gram-positive pathogens is a relevant concern, particularly in the hospital setting. Several antibiotics are now available to treat these drug-resistant pathogens, such as daptomycin, dalbavancin, linezolid, tedizolid, ceftaroline, ceftobiprole, and fosfomycin. However, antibiotic resistance can also affect these newer molecules. Overall, this is not a frequent phenomenon, but it is a growing concern in some settings and can compromise the effectiveness of these molecules, leaving few therapeutic options. We reviewed the available evidence about the epidemiology of antibiotic resistance to these antibiotics and the main molecular mechanisms of resistance, particularly methicillin-resistant Sthaphylococcus aureus, methicillin-resistant coagulase-negative staphylococci, vancomycin-resistant Enterococcus faecium, and penicillin-resistant Streptococcus pneumoniae. We discussed the interpretation of susceptibility tests when minimum inhibitory concentrations are not available. We focused on the risk of the emergence of resistance during treatment, particularly for daptomycin and fosfomycin, and we discussed the strategies that can be implemented to reduce this phenomenon, which can lead to clinical failure despite appropriate antibiotic treatment. The judicious use of antibiotics, epidemiological surveillance, and infection control measures is essential to preserving the efficacy of these drugs.

Ceftaroline: Systematic Review of Clinical Uses and Emerging Drug Resistance

OBJECTIVE

To assess the success rates of off-label uses of ceftaroline for infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and evaluate emerging ceftaroline resistance.

DATA SOURCES

We queried PubMed/MEDLINE, with the search term "Ceftaroline." Articles were restricted to the English language and year of publication (January 1, 2009-January 31, 2022).

STUDY SELECTION AND DATA EXTRACTION

Clinical trials, observational studies, and case reports that reported efficacy, safety, pharmacokinetics, use in MRSA infections other than acute bacterial skin infection and community-acquired pneumonia, and ceftaroline resistance were selected.

DATA SYNTHESIS

The search pooled 103 publications and all abstracts were reviewed. Forty-six articles that reported efficacy, safety, pharmacokinetics, or off-label use in multiple patients and 7 articles on ceftaroline resistance are used in this review. Ceftaroline has been approved for treatment of acute skin/soft tissue infection and community-acquired pneumonia. Ceftaroline's efficacy in off-label infections ranged from 66.7% to 87.3% depending on the types of infection. There were 14 documented cases of ceftaroline resistance associated with PBP2a changes.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Case series and observational studies have documented success with ceftaroline alone or in combination with vancomycin or daptomycin for treatment of MRSA bone and joint, endovascular, diabetic foot infections, and bacteremia from other causes.

CONCLUSION

Despite the lack of randomized controlled trials, ceftaroline is used as salvage therapy for different MRSA infections. The data from case series and observational studies are promising but ceftaroline should be used judiciously as ceftaroline-resistant MRSA begin to emerge.

Evaluation of in vitro activity of ceftaroline on methicillin resistant Staphylococcus aureus blood isolates from Iran

Background and Objectives:

Ceftaroline (CPT) is a novel cephalosporin with potent activity against methicillin-resistant Staphylococcus aureus (MRSA). Despite its recent introduction, CPT resistance in MRSA has been described worldwide. We aimed in the current study to evaluate the in vitro activity of CPT against 91 clinical MRSA and 3 MSSA isolates.

Materials and Methods:

Susceptibility of isolates to CPT was tested using E-test and disk diffusion (DD) method. The nucleotide sequence of the mecA gene and molecular types of isolates with reduced susceptibility to CPT were further studied to identify resistance conferring mutations in PBP2a and the genetic relatedness of the isolates respectively.

Results:

Overall, 92.5% of isolates were found to be CPT susceptible (MICs≤1mg/l) and 7 MRSA isolates were characterized with MIC=2mg/l and categorized as susceptible dose dependent. Compared to E-test, DD revealed a categorical agreement rate of 93.6% and the obtained rates for minor, major /very major error were found to be 6.3% and 0% respectively. The MRSA isolates with increased CPT MICs (n=7), belonged to spa types t030 (n=6) and t13927 (n=1) and all carried N146K substitution in PBP2a allosteric domain, except for one isolate which harbored a wild-type PBP2a.

Conclusion:

While resistance to CPT was not detected we found increased CPT MICs in 7.69% of MRSA isolates. Reduced susceptibility to CPT in the absence of mecA mutations is indicative of contribution of secondary chromosomal mutations in resistance development.

High-level ceftaroline resistance in a paediatric patient with invasive methicillin-resistant Staphylococcus aureus infection without previous ceftaroline exposure

WHAT IS KNOWN AN OBJECTIVE

Our objective is to report a paediatric case of high-level ceftaroline resistance without previous ceftaroline exposure.

CASE DESCRIPTION

A 20-month-old, 12 kg, female with invasive MRSA infection presented with high-level ceftaroline resistance with no previous ceftaroline exposure.

WHAT IS NEW AND CONCLUSION

To our knowledge, our case is the first report of high-level ceftaroline resistance evident in a paediatric patient with invasive infection due to MRSA, without history of prior ceftaroline exposure. This case illustrates the importance of weighing the risk of resistance with the benefits of use when starting therapy empirically prior to susceptibility results, even in patients without previous drug exposure.

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.

New Antibiotics for the Treatment of Acute Bacterial Skin and Soft Tissue Infections in Pediatrics

Acute bacterial skin and soft tissue infections (aSSTIs) are a large group of diseases that can involve exclusively the skin or also the underlying subcutaneous tissues, fascia, or muscles. Despite differences in the localization and severity, all these diseases are due mainly to Gram-positive bacteria, especially Staphylococcus aureus and Streptococcus pyogenes. aSSTI incidence increased considerably in the early years of this century due to the emergence and diffusion of community-acquired methicillin-resistant S. aureus (CA-MRSA). Despite the availability of antibiotics effective against CA-MRSA, problems of resistance to these drugs and risks of significant adverse events have emerged. In this paper, the present knowledge on the potential role new antibiotics for the treatment of pediatric aSSTIs is discussed. The most recent molecules that have been licensed for the treatment of aSSTIs include ozenoxacin (OZ), ceftaroline fosamil (CF), dalbavancin (DA), oritavancin (OR), tedizolid (TD), delafloxacin (DL), and omadacycline (OM). However, only OZ and CF have been licensed for use in children with aSSTIs, although the superiority of these antibiotics to those routinely used for the treatment of aSSTIs should be further demonstrated. Waiting for additional studies, OZ and CF should be prescribed for aSSTI treatment in the presence of the potential failure of old molecules.

Global priority pathogens: virulence, antimicrobial resistance and prospective treatment options

Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Salmonella spp. are part of a group of pathogens that pose a major threat to human health due to the emergence of multidrug-resistant strains. Moreover, these bacteria have several virulence factors that allow them to successfully colonize their hosts, such as toxins and the ability to produce biofilms, resulting in an urgent need to develop new strategies to fight these pathogens. In this review, we compile the most up-to-date information on the epidemiology, virulence and resistance of these clinically important microorganisms. Additionally, we address new therapeutic alternatives, with a focus on molecules with antivirulence activity, which are considered promising to combat multidrug-resistant bacteria.

Calculated parenteral initial treatment of bacterial infections: Bone and joint infections

This is the 10^th chapter of the guideline “Calculated initial parenteral treatment of bacterial infections in adults – update 2018” in the 2^nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience.

This chapter deals with bacterial Infections of bones, joints and prosthetic joints. One of the most pressing points is that after an initial empirical therapy a targeted antimicrobial which penetrates well to the point of infection and is tolerated well over the usually long duration of the therapy is chosen.

In Vitro Ceftaroline Resistance Selection of Methicillin-Resistant Staphylococcus aureus Involves Different Genetic Pathways

The pathways in the development of ceftaroline resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates belonging to the ST8, ST239, and ST228 were evaluated. Ceftaroline-resistant derivatives were isolated through selection during 40 passages. Ceftaroline MIC measurements and whole-genome sequencing were performed after 5, 20, and 40 passages. In two ST8 derivative isolates, ceftaroline MIC increased up to 128 mg/L. Mutations were acquired in gdpP and graS in one isolate after 20 passages and in gdpP in another after 40 passages. MIC for two ST239 derivatives increased to 128 mg/L. Substitutions in Pbp4 and polymorphisms in the upstream region of pbp4 were identified in both derivatives after 40 passages. In one isolate, additional mutation in gdpP and deletion in graR were detected. In an ST228 derivative, MIC increased to 32 mg/L with one mutation in penicillin-binding protein 2a (Y446N) detected after five passages and a second (E447K) after 20 passages. Three pathways in the development of ceftaroline resistance were identified. For ST8 and ST239 derivatives mutations were detected in gdpP and pbp4, respectively, whereas in ST228 - in mecA. Most derivatives harbored additional mutations whose potential role in the development of resistance has not been determined.

Methicillin-resistant Staphylococcus aureus in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice review the epidemiology, diagnosis, prevention, and management of methicillin-resistant Staphylococcus aureus (MRSA) infections in solid organ transplantation. Despite an increasing armamentarium of antimicrobials active against MRSA, improved diagnostic tools, and overall declining rates of infection, MRSA infections remain a substantial cause of morbidity and mortality in solid organ transplant recipients. Pre- and post-transplant MRSA colonization is a significant risk factor for post-transplant MRSA infection. The preferred initial treatment of MRSA bacteremia remains vancomycin. Hand hygiene, chlorhexidine bathing in the ICU, central-line bundles that focus on reducing unnecessary catheter use, disinfection of patient equipment, and the environment along with antimicrobial stewardship are all aspects of an infection prevention approach to prevent MRSA transmission and decrease healthcare-associated infections.

Antibiotic Resistance and the MRSA Problem

Staphylococcus aureus is capable of becoming resistant to all classes of antibiotics clinically available and resistance can develop through de novo mutations in chromosomal genes or through acquisition of horizontally transferred resistance determinants. This review covers the most important antibiotics available for treatment of S. aureus infections and a special emphasis is dedicated to the current knowledge of the wide variety of resistance mechanisms that S. aureus employ to withstand antibiotics. Since resistance development has been inevitable for all currently available antibiotics, new therapies are continuously under development. Besides development of new small molecules affecting cell viability, alternative approaches including anti-virulence and bacteriophage therapeutics are being investigated and may become important tools to combat staphylococcal infections in the future.

Application of Next-Generation Sequencing for Characterization of Surveillance and Clinical Trial Isolates: Analysis of the Distribution of β-lactamase Resistance Genes and Lineage Background in the United States

Background

Sequencing technologies and techniques have seen remarkable transformation and innovation that have significantly affected sequencing capability. Data analyses have replaced sequencing as the main challenge. This paper provides an overview on applying next-generation sequencing (NGS) and analysis and discusses the benefits and challenges. In addition, this document shows results from using NGS and bioinformatics tools to screen for β-lactamase genes and assess the epidemiological structure of Escherichia coli– and Klebsiella pneumoniae–causing bloodstream (BSIs) and urinary tract (UTIs) infections in patients hospitalized in the United States during the SENTRY Antimicrobial Surveillance Program for 2016.

Methods

A total of 3525 isolates (2751 E. coli and 774 K. pneumoniae) causing BSIs (n = 892) and UTIs (n = 2633) in hospitalized patients in the United States were included. Isolates were tested for susceptibility by broth microdilution, and those that met a minimum inhibitory concentration (MIC)–based screening criteria had their genomes sequenced and analyzed.

Results

A total of 11.6% and 16.1% of E. coli–causing UTIs and BSIs, respectively, met the MIC-based criteria, whereas 11.0% and 13.7% of K. pneumoniae isolates causing UTIs and BSIs, respectively, met the criteria. Among E. coli, bla_CTX-M variants (87.6% overall) prevailed (60.5% of CTX-M group 1 and 26.9% of group 9). A total of 60.3% of K. pneumoniae isolates carried bla_CTX-M variants (52.7% and 7.6% of groups 1 and 9, respectively). Two E. coli (0.6%) and 13 K. pneumoniae (12.9%) isolates harbored bla_KPC. Among KPC-producing K. pneumoniae (2 from BSIs and 11 from UTIs), 84.6% (11/13) were ST258 (CC258). Seventeen and 38 unique clonal complexes (CCs) were noted in E. coli that caused BSIs and UTIs, respectively, and CC131 (or ST131) was the most common CC among BSI (53.6%) and UTI (58.2%) isolates. Twenty-three and 26 CCs were noted among K. pneumoniae–causing BSIs and UTIs, respectively. CC258 (28.3%) prevailed in UTI pathogens, whereas CC307 (15.0%) was the most common CC among BSI isolates.

Conclusions

This study provides a benchmark for the distribution of β-lactamase genes and the population structure information for the most common Enterobacteriaceae species responsible for BSIs and UTIs in US medical centers during the 2016 SENTRY Program.

Evaluation of the Revised Ceftaroline Disk Diffusion Breakpoints When Testing a Challenge Collection of Methicillin-Resistant Staphylococcus aureus Isolates

We assessed ceftaroline disk diffusion breakpoints for Staphylococcus aureus when applying revised Clinical and Laboratory Standards Institute (CLSI) ceftaroline MIC breakpoints. Disk-MIC correlation was evaluated by testing a challenge collection (n = 158) of methicillin-resistant S. aureus (MRSA) isolates composed of 106 randomly selected isolates plus 52 isolates with decreased susceptibility to ceftaroline (MIC, 1 to 16 μg/ml). Disk diffusion was performed with 30-μg disks and Mueller-Hinton agar from 2 manufacturers each. Revised CLSI susceptible (S)/susceptible dose-dependent (SDD)/resistant (R) MIC breakpoints of ≤1/2 to 4/≥8 μg/ml were applied. The disk breakpoints that provided the lowest error rates were CLSI S/R breakpoints of ≥25 mm/≤19 mm, with no very major (VM) or major (Ma) errors and with minor (Mi) error rates of 0.0% for ≥2 doubling dilutions above the I or SDD (≥I + 2), 22.1% for I or SDD plus or minus 1 doubling dilution (I ± 1), and 2.3% for ≤2 doubling dilutions below the I or SDD ≤I - 2 (overall Mi error rate, 16.5%). No mutation in the penicillin-binding protein 2a (PBP2a) was observed in 5 of 15 isolates with a ceftaroline MIC of 2 μg/ml; 3 of 11 isolates with a ceftaroline MIC of 1 μg/ml exhibited mutations in the penicillin-binding domain (PBD; 1 isolate) or in the non-PBD (2 isolates). All isolates except 1, with a ceftaroline MIC of ≥4 μg/ml, showed ≥1 mutation in the PBD and/or non-PBD. In summary, results from the disk diffusion method showed a good correlation with those from the reference broth microdilution method. Our results also showed that the ceftaroline MIC distribution of isolates with no mutations in the PBP2a goes up to 4 μg/ml, and reference broth microdilution and disk diffusion methods do not properly separate wild-type from non-wild-type isolates.

DISC: Describing Infections of the Spine treated with Ceftaroline

OBJECTIVES

Infections of the spine lead to considerable morbidity and a high cost to the global healthcare system. Currently, evidence for using ceftaroline, an advanced-generation cephalosporin active against methicillin-resistant Staphylococcus aureus (MRSA), in spine infections is limited.

METHODS

Describing Infections of the Spine treated with Ceftaroline (DISC) is a multicentre, retrospective, cohort study that evaluated ceftaroline for treating spine infections. Patients were included if they were aged ≥18 years, diagnosed with a spine infection and treated with ceftaroline for ≥28 days. A control group was identified with the same inclusion criteria as the study population except they were treated with a comparator antibiotic for ≥28 days.

RESULTS

Thirty-seven patients were included each in the ceftaroline and control groups. MRSA was the most commonly identified pathogen. With no differences between groups in age, sex, race or co-morbidities (with the exception of chronic kidney disease), treatment with ceftaroline led to similar clinical success compared with the control group. Multivariate regression analysis did not show a significant difference between the two groups in terms of clinical success after controlling for other covariates (adjusted odds ratio=1.49; P=0.711). More patients who received ceftaroline were discharged to an extended-care or rehabilitation facility than home compared with controls (81% vs. 54%, respectively; P=0.024). Side effects and toxicities were rare, including one case of eosinophilic pneumonia in the ceftaroline group.

CONCLUSIONS

Ceftaroline appears to be a safe and effective therapy for infections of the spine, including from MRSA.

Use of Ceftaroline Fosamil in Children: Review of Current Knowledge and its Application

Ceftaroline is a novel cephalosporin recently approved in children for treatment of acute bacterial skin and soft tissue infections and community-acquired bacterial pneumonia (CABP) caused by methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae and other susceptible bacteria. With a favorable tolerability profile and efficacy proven in pediatric patients and excellent in vitro activity against resistant Gram-positive and Gram-negative bacteria, ceftaroline may serve as a therapeutic option for polymicrobial infections, CABP caused by penicillin- and ceftriaxone-resistant S. pneumoniae and resistant Gram-positive infections that fail first-line antimicrobial agents. However, limited data are available on tolerability in neonates and infants younger than 2 months of age, and on pharmacokinetic characteristics in children with chronic medical conditions and those with invasive, complicated infections. In this review, the microbiological profile of ceftaroline, its mechanism of action, and pharmacokinetic profile will be presented. Additionally, clinical evidence for use in pediatric patients and proposed place in therapy is discussed.

Resistance to Non-glycopeptide Agents in Serious Staphylococcus aureus Infections

The role of vancomycin in the treatment of serious Staphylococcus aureus infections, both methicillin-susceptible and methicillin-resistant, is becoming increasingly ineffective due to increasing MIC and failure. The development of reduced vancomycin susceptibility by S. aureus to glycopeptides highlights the need for clinicians to reexamine the roles of non-glycopeptide therapy. As the use of these alternative non-glycopeptides antimicrobials increases, it will become pertinent to monitor the rates of resistance. Large surveillance programs have provided data for resistance against S. aureus for the non-glycopeptides (daptomycin, ceftaroline, tigecycline, linezolid, and tedizolid). The current published literatures suggest that worldwide resistance rates to these non-glycopeptides for serious MRSA infections are still low. Implementation of antimicrobial stewardship programs will be crucial in prevention of resistance of these antimicrobials against S. aureus.