Safety profiles of old and new antimicrobials for the treatment of MRSA infections

Prevalence of Antimicrobial Resistance in Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli Isolates among Stillbirths and Deceased Under-Five Children in Sierra Leone: Data from the Child Health and Mortality Prevention Surveillance Sites from 2019 to 2022

Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae are associated with most nosocomial infections worldwide. Although gaps remain in the knowledge of their susceptibility patterns, these are in antimicrobial stewardship. This study aimed to describe antimicrobial susceptibility profiles of the above organisms isolated from postmortem blood from stillbirths and under-five children enrolled in the Child Health and Mortality Prevention Surveillance (CHAMPS) program in Sierra Leone. This was a surveillance study of bacteria isolates from postmortem blood cultures taken within 24 h of death from stillbirths and children aged 0-59 months between March 2019 and February 2022. This was followed by identification and antibiotic sensitivity testing using Becton Dickinson Phoenix M50 (USA). Descriptive analysis was used to characterize the isolates and their antimicrobial susceptibility patterns. Of 367 isolates, K. pneumoniae was the most frequently isolated organism (n = 152; 41.4%), followed by E. coli (n = 40; 10.9%) and E. cloacae (n = 35; 9.5%). Using BACTEC™ FX 40 (Franklin Lakes, NJ, USA), 367 isolates were identified from blood using bacteriological methods. Extended spectrum beta-lactamase (ESBL) was observed in 143 (94.1%) of K. pneumoniae isolates and 27 (65.5%) of E. coli isolates. Carbapenem-resistant organisms (CRO) were seen in 31 (20.4%) of K. pneumoniae and 5 (12.5%) of E. coli isolates. A multidrug resistance (MDR) pattern was most prevalent in E.cloacae (33/35; 94.3%), followed by K. pneumoniae (138/152; 90.8%). Our study showed a high prevalence of multidrug resistance among bacterial isolates in the catchment areas under surveillance by the CHAMPS sites in Sierra Leone.

Treatment of MRSA Infection: Where are We?

Staphylococcus aureus is a leading cause of septicemia, endocarditis, pneumonia, skin and soft tissue infections, bone and joint infections, and hospital-acquired infections. In particular, methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality, and continues to be a major public health problem. The emergence of multidrug-resistant MRSA strains along with the wide consumption of antibiotics has made anti-MRSA treatment a huge challenge. Novel treatment strategies (e.g., novel antimicrobials and new administrations) against MRSA are urgently needed. In the past decade, pharmaceutical companies have invested more in the research and development (R&D) of new antimicrobials and strategies, spurred by favorable policies. All research articles were collected from authentic online databases, including Google Scholar, PubMed, Scopus, and Web of Science, by using different combinations of keywords, including 'anti-MRSA', 'antibiotic', 'antimicrobial', 'clinical trial', 'clinical phase', clinical studies', and 'pipeline'. The information extracted from articles was compared to information provided on the drug manufacturer's website and Clinical Trials.gov (https://clinicaltrials.gov/) to confirm the latest development phase of anti-MRSA agents. The present review focuses on the current development status of new anti-MRSA strategies concerning chemistry, pharmacological target(s), indications, route of administration, efficacy and safety, pharmacokinetics, and pharmacodynamics, and aims to discuss the challenges and opportunities in developing drugs for anti-MRSA infections.

Therapeutic drug monitoring of glycopeptide antimicrobials: An overview of liquid chromatography-tandem mass spectrometry methods

Therapeutic drug monitoring (TDM) is a critical clinical tool used to optimize the safety and effectiveness of drugs by measuring their concentration in biological fluids. These fluids are primarily plasma or blood. TDM, together with real-time dosage adjustment, contributes highly to the successful management of glycopeptide antimicrobial therapies. Understanding pharmacokinetic/pharmacodynamic (PK/PD) properties is vital for optimizing antimicrobial therapies, as the efficacy of these therapies depends on both the exposure of the patient to the drug (PK) and pharmacodynamic (PD) parameters such as the in vitro estimated minimum drug concentration that inhibits bacterial growth (MIC). Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is widely recognized as the gold standard for measuring small molecules, such as antibiotics. This review provides a comprehensive overview of LC-MS/MS methods available for TDM of glycopeptide antibiotics, including vancomycin, teicoplanin, dalbavancin, oritavancin, and telavancin.

The Novel Oxazolidinone TBI-223 Is Effective in Three Preclinical Mouse Models of Methicillin-Resistant Staphylococcus aureus Infection

Staphylococcus aureus is an important cause of various infections in humans, including bacteremia, skin and soft tissue infections, and infections associated with implanted medical devices. The emergence of hospital- and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) underscores the urgent and unmet need to develop novel, safe, and effective antibiotics against these multidrug-resistant clinical isolates. Oxazolidinone antibiotics such as linezolid have excellent oral bioavailability and provide coverage against MRSA infections. However, their widespread and long-term use is often limited by adverse effects, especially myelosuppression. TBI-223 is a novel oxazolidinone with potentially reduced myelosuppression, compared to linezolid, but its efficacy against MRSA infections is unknown. Therefore, the preclinical efficacy of TBI-223 (80 and 160 mg/kg twice daily) was compared with that of linezolid (40 and 80 mg/kg twice daily) and sham treatment in mouse models of MRSA bacteremia, skin wound infection, and orthopedic-implant-associated infection. The dosage was selected based on mouse pharmacokinetic analysis of both linezolid and TBI-223, as well as measurement of the MICs. In all three models, TBI-223 and linezolid had comparable dose-dependent efficacies in reducing bacterial burden and disease severity, compared with sham-treated control mice. Taken together, these findings indicate that TBI-223 represents a novel oxazolidinone antibiotic that may provide an additional option against MRSA infections. Future studies in larger animal models and clinical trials are warranted to translate these findings to humans. IMPORTANCE Staphylococcus aureus is the predominant cause of bloodstream, skin, and bone infections in humans. Resistance to commonly used antibiotics is a growing concern, making it more difficult to treat staphylococcal infections. Use of the oxazolidinone antibiotic linezolid against resistant strains is hindered by high rates of adverse reactions during prolonged therapy. Here, a new oxazolidinone named TBI-223 was tested against S. aureus in three mouse models of infection, i.e., bloodstream infection, skin infection, and bone infection. We found that TBI-223 was as effective as linezolid in these three models. Previous data suggest that TBI-223 has a better safety profile than linezolid. Taken together, these findings indicate that this new agent may provide an additional option against MRSA infections. Future studies in larger animal models and clinical trials are warranted to translate these findings to humans.

A Systematic Review of Antibiotic Resistance Trends and Treatment Options for Hospital-Acquired Multidrug-Resistant Infections

Antimicrobial resistance is a major public health challenge described by the World Health Organization as one of the top 10 public health challenges worldwide. Drug-resistant microbes contribute significantly to morbidity and mortality in the hospital, especially in the critical care unit. The primary etiology of increasing antibiotic resistance is inappropriate and excessive use of antibiotics. The alarming rise of drug-resistant microbes worldwide threatens to erode our ability to treat infections with our current armamentarium of antibiotics. Unfortunately, the pace of development of new antibiotics by the pharmaceutical industry has not kept up with rising resistance to expand our options to treat microbial infections. The costs of antibiotic resistance include death and disability, extended hospital stays due to prolonged sickness, need for expensive therapies, rising healthcare expenditure, reduced productivity from time out of the workforce, and rising penury. This review sums up the common mechanisms, trends, and treatment options for hospital-acquired multidrug-resistant microbes.

Dalbavancin in the treatment of acute bacterial skin and skin structure and other infections: a safety evaluation

INTRODUCTION

Dalbavancin is a second-generation lipoglycopeptide that was approved since 2014 to treat acute bacterial skin and skin-structure infections (ABSSSI). Dalbavancin is characterized by Gram-positive activity and novel pharmacokinetic properties that result in a prolonged terminal half-life, allowing once weekly dosing in adults. A good safety profile was reported by randomized clinical trials and meta-analyses.

AREAS COVERED

Dalbavancin safety and tolerability data from trials and post-marketing studies were reviewed. While most trials included predominantly ABSSSI, 2 clinical trials and recent observational studies have explored the use of dalbavancin for off-label indications, mainly including bloodstream and osteoarticular infections.

EXPERT OPINION

The occurrence of drug-related adverse effects (AE) was similar between dalbavancin and comparators in clinical trials enrolling patients with ABSSSI. Most common AE included gastrointestinal symptoms, infusion reaction, and hypersensitivity. Low rates of drug discontinuation and serious AE were reported across studies. In the past 5 years, several observational studies have reported safety data on the use of dalbavancin, confirming its favorable safety profile. Nevertheless, data from dalbavancin off-label use often derived from prolonged (> 2 weeks) treatments with variable dosing regimens, were mainly retrospective, and lacked comparators. Further research is required to allow a reliable analysis of short- and long-term dalbavancin-related AE in non-ABSSSI.

Comparison of Anti-Microbic and Anti-Biofilm Activity Among Tedizolid and Radezolid Against Linezolid-Resistant Enterococcus faecalis Isolates

Background

The emergence and spread of linezolid-resistant Enterococcus faecalis (E. faecalis) have emerged as a serious threat to human health globally. Therefore, this study aims to compare the anti-microbic as well as the anti-biofilm activity of linezolid, tedizolid, and radezolid against linezolid-resistant E. faecalis.

Methods

A total of 2128 E. faecalis isolates were assessed from the First Affiliated Hospital of Wenzhou Medical University from 2011 to 2019. Antibiotic sensitivity was evaluated using the micro broth dilution method. Oxazolidinone-resistant chromosomal and plasmid-borne genes such as cfr, cfr(A), cfr(B), cfr(C), cfr(D), optrA, and poxtA were detected by PCR and then sequenced to detect the presence of mutations in the domain V of the 23S rRNA and the ribosomal proteins L3, L4, and L22. Conjugation experiments were conducted using the broth method. The inhibition and eradication of biofilm were evaluated through crystal violet staining, whereas the efflux pump activities were detected by agar dilution.

Results

Out of 2128 isolated E. faecalis, 71 (3.34%) were linezolid-resistant isolates in which the MICs of tedizolid and radezolid ranged from 1 to 4 μg/mL and 0.5–1 μg/mL, respectively. The MIC₅₀/MIC₉₀ of tedizolid and radezolid were 4 and 8-fold lower than the linezolid, respectively. Out of 71 resistant isolates, 57 (80.28%) carried optrA, 1 (1.41%) carried cfr, 4 (5.63%) carried optrA and cfr, and 6 (8.45%) carried optrA and cfr(D), with no mutations of 23S rRNA gene and ribosomal proteins L3, L4, and L22. Besides, the transfer rate of the optrA, cfr, and cfr(D) was 17.91%, 0% and 0%, respectively. Radezolid showed more effectiveness in eradicating biofilm (8 × MIC). However, tedizolid was more effective than radezolid and linezolid in inhibiting the biofilm formation (1/4 MIC, 1/8MIC, and 1/16MIC). Additionally, in combination with CCCP, the MICs of radezolid in all linezolid-resistant isolates decreased ≥4-fold.

Conclusion

Radezolid showed greater antimicrobial activity than tedizolid and linezolid against linezolid-resistant E. faecalis. However, both tedizolid and radezolid showed differential activity on biofilm inhibition, eradication, and efflux pump compared to linezolid. Thus, our study might bring important clinical value in the application of these drugs for resistant pathogenic strains.

Safety considerations with new antibacterial approaches for chronic bacterial prostatitis

Introduction: Chronic bacterial prostatitis (CBP) is a difficult-to-eradicate infection. Antibacterial therapy with currently licensed agents is hindered due to the increasing emergence of pathogen resistance worldwide and to frequent infection relapse. With limited treatment options, physicians are investigating new agents, which, however, may raise safety concerns.Areas covered: Antibacterial agents currently licensed for CBP were not considered. Available reports about the safety and efficacy of antibacterial agents that have been clinically tested or tentatively used to treat CBP in single cases were evaluated. This review also focused on agents targeting Gram-positive pathogens, whose prevalence as causative agents of CBP is increasing.Expert opinion: (i) Most antibacterial agents considered in this review have been administered off-label in the interest of patients, and their use requires particular caution. (ii) Reports describing the usage of many of the drugs reviewed here are still scant, and readers should be warned of the limited published evidence supporting therapy for CBP with these agents. (iii) As treatment must extend over several weeks, medium-term adverse events may occur and therapy should be individualized, taking into account the dosage and the potential toxicity of each specific antibiotic. Regarding dangerous drug-drug interactions, particular attention should be paid to the risk of ECG-QT-interval elongation.

Skin necrosis and calcifications after extravasation of vancomycin: a localised form of calciphylaxis?

Vancomycin is a tricyclic glycopeptide antibiotic produced from Streptococcus orientalis. There is much variation in the literature with regard to the recommended dose, dilution rate and type of infusion. Given the vesicant properties of vancomycin at supratherapeutic doses (>10mg/ml), tissue damage including blistering and necrosis have been reported. We report a rare case of bilateral cutaneous necrosis induced by accidental extravasation of vancomycin when being intravenously administered. The skin surrounding the injection site was marked by the appearance of subcutaneous calcifications. The development of iatrogenic skin calcinosis has not yet been described for the extravasation of vancomycin. The mechanism underlying the calcinosis observed in our case remains unclear, but we hypothesised a form of localised calciphylaxis induced by a local triggering factor. The ulcers progressed to re-epithelialisation following necrosis debridement and local conservative treatments. Given the increased prevalence of meticillin-resistant Staphylococcus aureus, which has prompted clinicians to gradually increase vancomycin dosage, clinicians should be aware of the high risk of skin toxicity in cases of vancomycin high-dose extravasation.

Investigation of radezolid interaction with non-canonical chloramphenicol binding site by molecular dynamics simulations

Radezolid is a promising antibiotic of oxazolidinone family, which is able to overcome effect of some linezolid resistance mechanisms of bacterial ribosomes. The structure of the radezolid complex with ribosomes was never published but, by analogy with linezolid, it is considered to prevent the binding of aminoacyl-tRNA to the A-site of the ribosome large subunit. However, as with linezolid, it can be assumed that radezolid binds to the alternative binding site existing in the A,A/P,P-ribosome. In the present article we have investigated this issue by molecular dynamics simulations and proposed the structure of the radezolid complex with a E. coli ribosome, which is consistent with available data of biochemical investigations of radezolid action.

Recent advances in antibacterial agents

Antimicrobial resistance is a global challenge and the effectiveness of old antibiotics is decreasing. Discovery and development of antibacterial agents have been accelerated to replenish the arsenal of antibiotics which is limited and shrinking. In recent years, significant advances have achieved in the antibacterial area, including new compounds of known classes and new compounds with new mechanisms. This review summarizes these advances and provides perspective on future directions of antibacterial agents.

Prevalence and Antibiotic Resistance of ESKAPE Pathogens Isolated in the Emergency Department of a Tertiary Care Teaching Hospital in Hungary: A 5-Year Retrospective Survey

Antibiotic treatments initiated on Emergency Departments (ED) are empirical. Therefore, knowledge of local susceptibility patterns is important. Despite this, data on expected pathogens and their resistance profile are scarce from EDs internationally. The study aim was to assess the epidemiology and resistance patterns of bacterial isolates from a tertiary-care ED over 5 years, focusing on ESKAPE bacteria (including the Enterobacterales group). After removal of duplicates, n = 6887 individual bacterial isolates were recovered, out of which n = 4974 (72.22%) were ESKAPE isolates. E. coli was the most frequent isolate (2193, 44.1%), followed by the Klebsiella genus (664; 13.4%). The third most frequent isolate was S. aureus (561, 11.3%). In total, multi-drug resistance (MDR) was present in 23.8% and was most prevalent in A. baumanii (65.5%), P. mirabilis (42.7%), and K. pneumoniae (32.6%). MRSA was isolated in 19.6%, while ESBL-producing Enterobacterales in 17.7%, and these were associated with remarkably higher resistance to other antibacterials as well. Difficult-to-treat resistance (DTR) was detected in 0.5%. The frequent isolation of some ESKAPE bacteria and the detected considerable acquired resistance among ED patients raise concern. The revealed data identified problematic pathogens and will guide us to set up the optimal empiric antibiotic protocol for clinicians.

Current role of oxazolidinones and lipoglycopeptides in skin and soft tissue infections

PURPOSE OF REVIEW

An increase of skin and soft tissue infections involving Staphylococcus aureus has been reported in community and hospital settings. Methicillin resistance in S. aureus is associated with treatment failure and increased mortality. Recently, new antimicrobials with enhanced activity against methicillin-resistant Staph. aureus have been approved for the treatment of skin and soft tissue infections. Among these, novel oxazolidinones and lipoglycopeptides represent options with favorable pharmacokinetic characteristics and safety profiles.

RECENT FINDINGS

Newly approved compounds include tedizolid, characterized by the availability of both oral and intravenous formulation and once daily administration and dalbavancin, a long-acting antimicrobial allowing for weekly administration. These new molecules present advantages, such as enhanced activity against multidrug-resistant Gram-positive bacteria and favorable safety profiles.

SUMMARY

We have reviewed the pharmacokinetic characteristics and the implications for use in skin and soft tissue infections of tedizolid and dalbavancin. Advantages associated with the use of these compounds include the possibility for early patient discharge, reduced hospital length of stay, and outpatient treatment, with potential impact on morbidity, mortality, and overall health-care costs.

Linezolid use in German acute care hospitals: results from two consecutive national point prevalence surveys

Background

Linezolid belongs to a reserve group of antibiotics. In recent years, reports on linezolid resistance in gram-positive cocci have become more frequent. Overuse of linezolid is a relevant factor for resistance development. The objective of this study was to describe current prescription practices of linezolid in German hospitals and identify targets for antimicrobial stewardship interventions.

Methods

We analyzed all linezolid prescriptions from the datasets of the consecutive national point prevalence surveys performed in German hospitals in 2011 and 2016. In both surveys, data on healthcare-associated infections and antimicrobial use were collected following the methodology of the European Centre for Disease Prevention and Control.

Results

Overall, the percentage of linezolid among all documented antimicrobials increased significantly from 2011 to 2016 (p < 0.01). In 2011, 0.3% (119 of 41,539) patients received linezolid, in 2016 this proportion was significantly higher (0.4%; 255 of 64,412 patients; p < 0.01). In 2016, intensive care units (ICUs) were the wards most frequently prescribing linezolid. The largest proportion of patients receiving linezolid were non-ICU patients. Roughly 38% of linezolid prescriptions were for treatment of skin/soft tissue and respiratory tract infections. In 2016, linezolid was administered parenterally in 70% (n = 179) of cases. Multivariable analysis showed that the ward specialty ICU posed an independent risk factor, while Northern and Southwestern regions in Germany were independent protective factors for a high rate of linezolid prescriptions.

Conclusions

In conclusion, we detected potentials for improving linezolid prescription practices in German hospitals. Given the emergence of linezolid resistance, optimization of linezolid use must be a target of future antimicrobial stewardship activities.

Risk stratification and treatment of ICU-acquired pneumonia caused by multidrug- resistant/extensively drug-resistant/pandrug-resistant bacteria

PURPOSE OF REVIEW

Describe the risk factors and discuss the management of multidrug-resistant (MDR) bacteria responsible for pneumonia among critically ill patients, including methicillin-resistant Staphylococcus aureus, extended spectrum beta-lactamase-producing Enterobactericeae, carbapenem-resistant Enterobactericeae, multidrug resistant Pseudomonas aeruginosa, and Acinetobacter baumannii.

RECENT FINDINGS

Multiple factors have been associated with infections because of MDR bacteria, including prolonged hospital stay, presence of invasive devices, mechanical ventilation, colonization with resistant pathogens, and use of broad-spectrum antibiotics. Management of these infections includes the prompt use of appropriate antimicrobial therapy, implementation of antimicrobial stewardship protocols, and targeted active microbiology surveillance. Combination therapy and novel molecules have been used for the treatment of severe infections caused by resistant bacteria.

SUMMARY

The exponential increase of antimicrobial resistance among virulent pathogens currently represents one of the main challenges for clinicians in the intensive care unit. Knowledge of the local epidemiology, patient risk stratification, and infection-control policies remain key elements for the management of MDR infections. Results from clinical trials on new molecules are largely awaited.

The safety of treatment options for acute bacterial skin and skin structure infections

INTRODUCTION

Acute bacterial skin and skin-structure infections (ABSSSI) may develop in both in-patients and out-patients, possibly with a severe clinical presentation. Since most phase 3 randomized clinical trials have shown non-inferiority in efficacy across different agents, considerations regarding their different safety profiles inevitably play a crucial role in the everyday choice about which of them should be employed for the treatment of ABSSSI.

AREAS COVERED

In this review, the authors discuss the safety profile of different treatment options for ABSSSI.

EXPERT OPINION

The spread of methicillin-resistant Staphylococcus aureus (MRSA) in the last decades has inevitably influenced the therapeutic approach to ABSSSI. Adequate knowledge of the peculiar toxicity profile of each drug active against MRSA is essential for guiding, monitoring and managing adverse events, in turn reducing any unfavorable impact of toxicity on patients' outcomes. In the next five years, potential toxicity will play a critical role in establishing the best available therapy for each specific patient, together with consideration regarding the possibility of avoiding hospitalization or allowing a switch from intravenous to oral therapy and early discharge.

Current and emerging pharmacotherapy for the treatment of infections following open-heart surgery

INTRODUCTION

Patients undergoing open-heart surgery may suffer from postoperative complications, including severe infections. Antimicrobials to treat infectious complications in this population should be selected thoughtfully, taking into account three different and fundamental issues: (i) the site of infection; (ii) the suspected or proven causative agent and its susceptibility pattern; and (iii) the risk of suboptimal pharmacokinetic characteristics and potential toxicity of the chosen drug/s.

AREAS COVERED

The present narrative review summarizes the current and future antimicrobial options for the treatment of infections developing after open-heart surgery.

EXPERT OPINION

The pharmacological treatment of infections developing in cardiac surgery patients poses peculiar challenges, including the need for an active empirical therapy for severe events such as bloodstream infections, deep sternal wound infections, or early-onset postoperative prosthetic endocarditis. In addition, the risk for multidrug-resistant pathogens should also be taken into account in endemic areas. A multidisciplinary evaluation on a patient-by-patient basis, deeply involving infectious diseases specialists and cardiothoracic surgeons, remains essential for appropriately balancing both short-term and long-term risks and benefits of any possible surgical reintervention in combination with adequate pharmacotherapy.

Management of bacterial and fungal infections in end stage liver disease and liver transplantation: Current options and future directions

Patients with liver cirrhosis are susceptible to infections due to various mechanisms, including abnormalities of humoral and cell-mediated immunity and occurrence of bacterial translocation from the intestine. Bacterial infections are common and represent a reason for progression to liver failure and increased mortality. Fungal infections, mainly caused by Candida spp., are often associated to delayed diagnosis and high mortality rates. High level of suspicion along with prompt diagnosis and treatment of infections are warranted. Bacterial and fungal infections negatively affect the outcomes of liver transplant candidates and recipients, causing disease progression among patients on the waiting list and increasing mortality, especially in the early post-transplant period. Abdominal, biliary tract, and bloodstream infections caused by Gram-negative bacteria [e.g., Enterobacteriaceae and Pseudomonas aeruginosa (P. aeruginosa)] and Staphylococcus spp. are commonly encountered in liver transplant recipients. Due to frequent exposure to broad-spectrum antibiotics, invasive procedures, and prolonged hospitalizations, these patients are especially at risk of developing infections caused by multidrug resistant bacteria. The increase in antimicrobial resistance hampers the choice of an adequate empiric therapy and warrants the knowledge of the local microbial epidemiology and the implementation of infection control measures. The main characteristics and the management of bacterial and fungal infections in patients with liver cirrhosis and liver transplant recipients are presented.

Real-Life Evidence for Tedizolid Phosphate in the Treatment of Cellulitis and Wound Infections: A Case Series

Introduction

Tedizolid phosphate 200 mg, once daily for 6 days, has recently been approved for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSIs) in several countries; however, clinical experience in real-life settings is currently limited. Here, we report on the use of tedizolid with an extended treatment duration for complex and severe ABSSSIs in real-world clinical settings.

Methods

Two patients with cellulitis and two patients with surgical site infection (SSI), aged 26–60 years, were treated with tedizolid phosphate 200 mg, intravenous/oral (IV/PO) or IV only, once daily at four different institutions.

Results

Two morbidly obese patients had non-necrotizing, non-purulent severe cellulitis, which were complicated by sepsis or systemic inflammatory response syndrome plus myositis. One female patient failed on first-line empiric therapy with IV cefalotin, clindamycin and imipenem (3–4 days), and was switched to IV/PO tedizolid (7 + 5 days). One male patient received IV clindamycin plus IV/PO tedizolid (5 + 5 days), but clindamycin was discontinued on Day 3 due to an adverse event. For both patients, clinical signs and symptoms improved within 72 h, and laboratory results were normalized by Days 7 and 8, respectively. Two other patients (one obese, diabetic female with chronic hepatitis and chronic obstructive pulmonary disease) had complicated SSIs occurring 10 days after hernia repair with mesh or 3 months after spinal fusion surgery with metal implant. First patient with previous methicillin-resistant Staphylococcus aureus (MRSA) bacteremia received a 7-day tedizolid IV course empirically. The second patient with culture-confirmed MRSA infection received a 14-day IV course. Both patients responded within 72 h, and local and systemic signs normalized by end of treatment. There were no reports of thrombocytopenia.

Conclusion

Tedizolid phosphate 200 mg for 7–14 days was a favored treatment option for patients with severe/complex ABSSSIs, and was effective following previous treatment failure or in late-onset infections.

Funding

Editorial assistance and the article processing charges were funded by Bayer AG, Berlin, Germany.

What is new in the management of skin and soft tissue infections in 2016?

PURPOSE OF REVIEW

Skin and soft tissue infections (SSTIs) are the most frequent infectious cause of referrals to emergency departments and hospital admissions in developed world, contributing to significant morbidity and healthcare expenditures. We sought to review recent literature covering epidemiology and management of SSTIs.

RECENT FINDINGS

Incidence trends of SSTIs were increasing worldwide with Staphylococcus aureus and streptococci predominating and methicillin-resistant S. aureus (MRSA) posing additional challenges, because of high rates of treatment failure and relapse. Development of new antimicrobials was associated with an appraisal of regulatory definitions and endpoints. Prediction of clinical response can be very tricky, because of variable risk factors for recurrence or treatment failure, depending mostly on the host. Precise indications for new antimicrobials should be established; their integration into clinical practice algorithms may serve reduction of unnecessary admissions, overtreatment and total costs.

SUMMARY

New antimicrobials with activity against MRSA have been recently launched. Long-acting agents, mainly oritavancin and dalbavancin, provide the opportunity of single-dose treatment and early discharge. Further outpatient treatment options include new per os antibiotics such as oxazolidinones. Validated assessment tools are urgently needed to support decision-making toward rational resource utilization and delivery of optimal treatment.

Baseline Competency Assessment of Pharmacists Prescribing and Managing Vancomycin Therapy in the Regina Qu'Appelle Health Region

Background

Pharmacists in the Regina Qu'Appelle Health Region (RQHR), Saskatchewan, independently dose, monitor, and adjust vancomycin therapy. No framework exists for ongoing competency assessment of pharmacists.

Objectives

The primary objective was to determine pharmacists' overall level of competency for all components of the vancomycin prescribing procedure. The secondary objectives were to determine competency for individual prescribing phases, to stratify overall competency in relation to pharmacist and patient factors, and to identify the 3 most frequent errors.

Methods

A retrospective chart audit was performed of patients who received a prescription for vancomycin between November 1, 2015, and January 31, 2016. Patients were included if they received pharmacist-prescribed vancomycin as an inpatient or outpatient of an RQHR facility. Patients under the care of a pediatrician, those receiving vancomycin for surgical prophylaxis or via any route other than the IV route, and those whose vancomycin was prescribed by a current pharmacy resident were excluded. A rubric was created that assigned a numeric value for the appropriate completion of various procedure criteria.

Results

A total of 326 patients received vancomycin during the study period, of whom 200 met the inclusion criteria, representing 511 discrete episodes of prescribing by 42 pharmacists. The median overall competency rate, for all phases of prescribing, was 100% (interquartile range [IQR] 90.1%-100%). The median competency rates for the empiric therapy and monitoring phases were 94.4% (IQR 88.9%-100%) and 100% (IQR 87.5%-100%), respectively. No statistically significant differences were found in relation to pharmacists' experience or postbaccalaureate education, patients' level of acuity, or timing of prescribing. The competency score was significantly higher among pharmacists prescribing for patients with normal renal function than among those prescribing for patients with reduced renal function (p = 0.008). The 3 most common errors were failure to document risk factors for nephrotoxicity, failure to document requirement to obtain future trough levels, and failure to document that samples for trough levels had been drawn correctly.

Conclusions

During the study period, pharmacists at RQHR showed competency in all phases of vancomycin prescribing using the approved procedure. Documentation of clinical plans and assessments was identified as an area for improvement.

In vitro activity of tedizolid and comparator agents against Gram-positive pathogens responsible for bone and joint infections

Tedizolid, a second-generation oxazolidinone that displays a potent activity against Gram-positive pathogens, could be an interesting option for the treatment of bone and joint infections (BJIs). The aim of the study was to determine minimal inhibitory concentration (MIC) of tedizolid against a collection of 359 clinical isolates involved in clinically-documented BJIs and to compare them to those of comparator agents used in Gram-positive infections. Of the 104 Staphylococcusaureus and 102 coagulase-negative staphylococci (CoNS) isolates, 99 and 92 % were categorized as susceptible to tedizolid, respectively (MIC25=0.12/0.25 µg ml^-1 and MIC90=0.25/0.5 µg ml^-1), regardless of their methicillin resistance. MIC50 and MIC90 for the 51 enterococci, the 50 Corynebacterium spp. and the 52 Propionibacterium spp. were either equal or inferior to 0.5 µg ml^-1. Altogether, tedizolid possessed a potent in vitro activity against most of the BJI Gram-positive pathogens with 95 % of them exhibiting a MIC ≤0.5 µg ml^-1.

Lactic Acidosis Induced by Linezolid Mimics Symptoms of an Acute Intracranial Bleed: A Case Report and Literature Review

Lactic acidosis is common and most often associated with disturbed acid-base balance. Rarely, it can be a life-threatening medication side effect. Hence, determining the etiology of lactic acidosis early in patients is paramount in choosing the correct therapeutic intervention. Although lactic acidosis as an adverse drug reaction of linezolid is a well-recognized and documented clinical entity, the occurrence of such mimicking an acute intracranial bleed has not been reported to our knowledge. The following case is presented as an example of such an occurrence. A 67-year-old woman presented to the emergency department for lethargy, nausea and syncope. The head CT did not demonstrate any bleeding or mass effect, but lab results were significant for elevated lactic acid. The patient recently underwent left total hip replacement surgery, which was complicated by a methicillin-resistant Staphylococcus aureus (MRSA) infection. She received 6 weeks of oral linezolid therapy. And upon learning that key part of her history, the linezolid was discontinued. Her lactic acid rapidly normalized and she was discharged home. Several publications demonstrate that linezolid induces lactic acidosis by disrupting crucial mitochondrial functions. It is essential that clinicians are aware that linezolid can cause lactic acidosis. And, the important reminder is that adverse drug reactions can often mimic common diseases. If it is not recognized early, ominous clinical consequences may occur. In conclusion, linezolid should be suspected and included in the differential diagnosis if lactic acidosis exists with an uncommon clinical picture.

Dalbavancin for the treatment of paediatric infectious diseases

To review the topics of interest related to the use of dalbavancin in paediatric patients. PubMed was used to search for all of the studies published over the last 15 years using the key word "dalbavancin". A total of 36 manuscripts were selected, and due to the limited pediatric experience a further research was performed in order to identify clinical trials ongoing. Three studies that concerned children were found in clinicaltrials.gov. This review considers also the manuscripts published on the adult population in order to highlight the gaps requiring further research at pediatric age. Dalbavancin has emerged as a promising agent against resistant Gram-positive invasive infections. It is approved in the United States and Europe for the treatment of adult patients with acute bacterial skin and skin structure infections (SSTIs). Compared to other available antibiotics that are active against multi-resistant bacteria, the advantages of dalbavancin include a lower potential for drug interactions and the possibility of fewer required doses due to a longer half-life. Pharmacokinetic characteristics of dalbavacin are attractive for its clinical impact, especially for children who may avoid prolonged hospitalization and central venous access. However, further studies are needed to establish its appropriate paediatric dosage before it can be licensed for use in newborns and children. For younger patients, at a time when infections due to multidrug-resistant Gram-positive pathogens are increasing, dosage, efficacy and safety data for dalbavancin are needed to ensure the highest antimicrobial efficacy while also minimizing the risk of adverse events.

Pattern and Predictors of Medication Dosing Errors in Chronic Kidney Disease Patients in Pakistan: A Single Center Retrospective Analysis

BACKGROUND

Chronic kidney disease (CKD) alters the pharmacokinetic and pharmacodynamic response of various drugs and increases the risk of toxicity. The data regarding the pattern and predictors of medication dosing errors is scare from the developing countries. Therefore, the present study was conducted to assess the pattern and predictors of medication dosing errors in CKD patients in a tertiary care setting in Pakistan.

METHODS

A retrospective study design was employed and medical charts of all those CKD patients who had an eGFR ≤60ml/min/1.73m2, hospitalization ≥24 hours, and admitted in the nephrology unit during January 2013 to December 2014 were assessed. Descriptive statistics and the logistic regression analysis were done using IBM SPSS version 20.

RESULTS

In total, 205 medical charts were assessed. The mean age of patients was 38.64 (±16.82) years. Overall, 1534 drugs were prescribed to CKD patients, of which, nearly 34.0% drugs required dose adjustment. Among those drugs, only 41.8% were properly adjusted, and the remaining 58.2% were unadjusted. The logistic regression analysis revealed that the medication dosing errors were significantly associated with the CKD stages, i.e. stage 4 (OR 0.054; 95% CI [0.017-0.177]; p <0.001) and stage 5 (OR 0.098; 95% CI [0.040-0.241]; p <0.001), the number of prescribed medicines ≥ 5 (OR 0.306; 95% CI [0.133-0.704]; p 0.005), and the presence of a comorbidity (OR 0.455; 95% CI [0.226-0.916]; p 0.027) such as the hypertension (OR 0.453; 95% CI [0.231-0.887]; p 0.021).

CONCLUSIONS

It is concluded that more than half drugs prescribed to CKD patients requiring dose adjustment were unadjusted. The predictors of medication dosing errors were the severe-to-end stages of chronic kidney disease, the presence of a comorbidity such as hypertension, and a higher number of prescribed medicines. Therefore, attention should be paid to these risk factors.

Staphylococcus aureus: the current state of disease, pathophysiology and strategies for prevention

Staphylococcus aureus is both a commensal organism and also an important opportunistic human pathogen, causing a variety of community and hospital-associated pathologies, such as bacteremia-sepsis, endocarditis, pneumonia, osteomyelitis, arthritis and skin diseases. The resurgence of S. aureus during the last decade in many settings has been facilitated not only by bacterial antibiotic resistance mechanisms but also by the emergence of new S. aureus clonal types with increased expression of virulence factors and the capacity to neutralize the host immune response. Prevention of the spread of S. aureus infection relies on the use of contact precautions and adequate procedures for infection control that so far have not been fully effective. Prevention using a prophylactic vaccine would complement these processes, having the potential to bring additional, significant progress toward decreasing invasive disease due to S. aureus.

Real-world daptomycin use across wide geographical regions: results from a pooled analysis of CORE and EU-CORE

Background

Pooled data from two large registries, Cubicin^® Outcomes Registry and Experience (CORE; USA) and European Cubicin^® Outcomes Registry and Experience (EU-CORE; Europe, Latin America, and Asia), were analyzed to determine the characteristics and clinical outcomes of daptomycin therapy in patients with Gram-positive infections across wide geographical regions.

Methods

Patients receiving at least one dose of daptomycin between 2004 and 2012 for the treatment of Gram-positive infections were included. Clinical success was defined as an outcome of ‘cured’ or ‘improved’. Post-treatment follow-up data were collected for a subset of patients (CORE: osteomyelitis and orthopedic foreign body device infection; EU-CORE: endocarditis, intracardiac/intravascular device infection, osteomyelitis, and orthopedic device infection). Safety was assessed for up to 30 days after daptomycin treatment.

Results

In 11,557 patients (CORE, 5482; EU-CORE, 6075) treated with daptomycin (median age, 62 [range, 1–103] years), the most frequent underlying conditions were cardiovascular disease (54.7 %) and diabetes mellitus (28.0 %). The most commonly treated primary infections were complicated skin and soft tissue infection (cSSTI; 31.2 %) and bacteremia (21.8 %). The overall clinical success rate was 77.2 % (uncomplicated SSTI, 88.3 %; cSSTI, 81.0 %; osteomyelitis, 77.7 %; foreign body/prosthetic infection (FBPI), 75.9 %; endocarditis, 75.4 %; and bacteremia, 69.5 %). The clinical success rate was 79.1 % in patients with Staphylococcus aureus infections (MRSA, 78.1 %). An increasing trend of high-dose daptomycin (>6 mg/kg/day) prescribing pattern was observed over time. Clinical success rates were higher with high-dose daptomycin treatment for endocarditis and FBPI. Adverse events (AEs) and serious AEs possibly related to daptomycin therapy were reported in 628 (5.4 %) and 133 (1.2 %) patients, respectively.

Conclusions

The real-world data showed that daptomycin was effective and safe in the treatment of various Gram-positive infections, including those caused by resistant pathogens, across wide geographical regions.