Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Early Initiation of Ceftaroline-Based Combination Therapy for Methicillin-resistant Staphylococcus aureus Bacteremia

Purpose

Monotherapy with vancomycin or daptomycin remains guideline-based care for methicillin-resistant Staphylococcus aureus bacteremia (MRSA-B) despite concerns regarding efficacy. Limited data support potential benefit of combination therapy with ceftaroline as initial therapy. We present an assessment of outcomes of patients initiated on early combination therapy for MRSA-B.

Methods

This was a single-center, retrospective study of adult patients admitted with MRSA-B between July 1, 2017 and April 31, 2023. During this period, there was a change in institutional practice from routine administration of monotherapy to initial combination therapy for most patients with MRSA-B. Combination therapy included vancomycin or daptomycin plus ceftaroline within 72 hours of index blood culture and monotherapy was vancomycin or daptomycin alone. The primary outcome was a composite of persistent bacteremia, 30-day all-cause mortality, and 30-day bacteremia recurrence. Time to microbiological cure and safety outcomes were assessed. All outcomes were assessed using propensity score-weighted logistic regression.

Results

Of 213 patients included, 118 received monotherapy (115 vancomycin, 3 daptomycin) and 95 received combination therapy with ceftaroline (76 vancomycin, 19 daptomycin). The mean time from MRSA-positive molecular diagnostic blood culture result to combination therapy was 12.1 hours. There was no difference between groups for the primary composite outcome (OR 1.58, 95% CI 0.60, 4.18). Time to microbiological cure was longer with combination therapy (mean difference 1.50 days, 95% CI 0.60, 2.41). Adverse event rates were similar in both groups.

Conclusions

Early initiation of ceftaroline-based combination therapy did not improve outcomes for patients with MRSA-B in comparison to monotherapy therapy.

Development of Oxadiazolone Activity-Based Probes Targeting FphE for Specific Detection of Staphylococcus aureus Infections

Staphylococcus aureus (S. aureus) is a major human pathogen that is responsible for a wide range of systemic infections. Since its propensity to form biofilms in vivo poses formidable challenges for both detection and treatment, tools that can be used to specifically image S. aureus biofilms are highly valuable for clinical management. Here, we describe the development of oxadiazolone-based activity-based probes to target the S. aureus-specific serine hydrolase FphE. Because this enzyme lacks homologues in other bacteria, it is an ideal target for selective imaging of S. aureus infections. Using X-ray crystallography, direct cell labeling, and mouse models of infection, we demonstrate that oxadiazolone-based probes enable specific labeling of S. aureus bacteria through the direct covalent modification of the FphE active site serine. These results demonstrate the utility of the oxadizolone electrophile for activity-based probes and validate FphE as a target for the development of imaging contrast agents for the rapid detection of S. aureus infections.

Deep learning model for personalized prediction of positive MRSA culture using time-series electronic health records

Methicillin-resistant Staphylococcus aureus (MRSA) poses significant morbidity and mortality in hospitals. Rapid, accurate risk stratification of MRSA is crucial for optimizing antibiotic therapy. Our study introduced a deep learning model, PyTorch_EHR, which leverages electronic health record (EHR) time-series data, including wide-variety patient specific data, to predict MRSA culture positivity within two weeks. 8,164 MRSA and 22,393 non-MRSA patient events from Memorial Hermann Hospital System, Houston, Texas are used for model development. PyTorch_EHR outperforms logistic regression (LR) and light gradient boost machine (LGBM) models in accuracy (AUROCPyTorch_EHR = 0.911, AUROCLR = 0.857, AUROCLGBM = 0.892). External validation with 393,713 patient events from the Medical Information Mart for Intensive Care (MIMIC)-IV dataset in Boston confirms its superior accuracy (AUROCPyTorch_EHR = 0.859, AUROCLR = 0.816, AUROCLGBM = 0.838). Our model effectively stratifies patients into high-, medium-, and low-risk categories, potentially optimizing antimicrobial therapy and reducing unnecessary MRSA-specific antimicrobials. This highlights the advantage of deep learning models in predicting MRSA positive cultures, surpassing traditional machine learning models and supporting clinicians' judgments.

Descriptive evaluation of patients receiving one-time intravenous vancomycin doses at a large academic medical center emergency department

BACKGROUND

Intravenous (IV) vancomycin is commonly used to treat a variety of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). The practice of administering a single dose of IV vancomycin prior to emergency department (ED) discharge may be clinically ineffective and foster antimicrobial resistance. Furthermore, this practice introduces an unnecessary infection risk along with preventable adverse effects while potentially increasing ED length of stay (LOS). There is a paucity of literature identifying patient characteristics and objective findings in this patient population, which may foster future antimicrobial stewardship initiatives in the ED.

METHODS

This was a single-center, retrospective, descriptive analysis of adult patients seen in the ED between January 2020 and January 2023 who received a single dose of IV vancomycin and were subsequently discharged from the ED without hospital admission. Information was collected on patient demographics and select comorbidities, vancomycin indication and dosing, ED LOS, initial vitals and labs, concomitant antibiotics administered, culture results, 30-day return ED visits and admissions, and antibiotics prescribed at ED discharge.

RESULTS

A total of 295 patients met inclusion criteria. A total of 32.1% of patients met SIRS criteria. The most commonly selected order indication for IV vancomycin was "skin and skin structure infection" (41%). A total of 86.1% of patients received concomitant antibiotics in the ED and only 54.6% of patients were prescribed oral antibiotics at ED discharge. A total of 80% of patients had at least one culture obtained during the ED visit. In those who had at least one culture obtained, 78.4% of patients had negative cultures and 4.2% of patients had MRSA positive cultures, with MRSA skin cultures being the most common (3.1%). Return ED visits and admissions within 30 days were not statistically significantly different between patients who did and did not receive oral antibiotics at ED discharge.

CONCLUSIONS

Despite a lack of clinical efficacy reported in prior literature and the potential risks, administration of a one-time dose of IV vancomycin prior to ED discharge is commonly encountered in clinical practice. There are opportunities for enhanced antimicrobial stewardship related to IV vancomycin use in the ED. Areas of future focus include the utilization of oral antimicrobials when clinically appropriate, particularly for skin and soft tissue infections, and clarification of antibiotic allergies.

Flucloxacillin worsens while imipenem-cilastatin protects against vancomycin-induced kidney injury in a translational rat model

BACKGROUND AND PURPOSE

Vancomycin is one of the most common clinical antibiotics, yet acute kidney injury is a major limiting factor. Common combinations of antibiotics with vancomycin have been reported to worsen and improve vancomycin-induced kidney injury. We aimed to study the impact of flucloxacillin and imipenem-cilastatin on kidney injury when combined with vancomycin in our translational rat model.

EXPERIMENTAL APPROACH

Male Sprague-Dawley rats received allometrically scaled (1) vancomycin, (2) flucloxacillin, (3) vancomycin + flucloxacillin, (4) vancomycin + imipenem-cilastatin or (5) saline for 4 days. Kidney injury was evaluated via drug accumulation and urinary biomarkers including urinary output, kidney injury molecule-1 (KIM-1), clusterin and osteopontin. Relationships between vancomycin accumulation in the kidney and urinary kidney injury biomarkers were explored.

KEY RESULTS

Urinary output increased every study day for vancomycin + flucloxacillin, but after the first dose only in the vancomycin group. In the vancomycin + flucloxacillin group, urinary KIM-1 increased on all days compared with vancomycin. In the vancomycin + imipenem-cilastatin group, urinary KIM-1 was decreased on Days 1 and 2 compared with vancomycin. Similar trends were observed for clusterin. More vancomycin accumulated in the kidney with vancomycin + flucloxacillin compared with vancomycin and vancomycin + imipenem-cilastatin. The accumulation of vancomycin in the kidney tissue correlated with increasing urinary KIM-1.

CONCLUSIONS AND IMPLICATIONS

Vancomycin + flucloxacillin caused more kidney injury compared with vancomycin alone and vancomycin + imipenem-cilastatin in a translational rat model. The combination of vancomycin + imipenem-cilastatin was nephroprotective.

Dalbavancin Sequential Therapy for Gram-Positive Bloodstream Infection: A Multicenter Observational Study

INTRODUCTION

Long-acting lipoglycopeptides such as dalbavancin may have utility in patients with Gram-positive bloodstream infections (BSI), particularly in those with barriers to discharge or who require prolonged parenteral antibiotic courses. A retrospective cohort study was performed to provide further multicenter real-world evidence on dalbavancin use as a sequential therapy for Gram-positive BSI.

METHODS

One hundred fifteen patients received dalbavancin with Gram-positive BSI, defined as any positive blood culture or diagnosed with infective endocarditis, from 13 centers geographically spread across the United States between July 2015 and July 2021.

RESULTS

Patients had a mean (SD) age of 48.5 (17.5) years, the majority were male (54%), with many who injected drugs (40%). The most common infection sources (non-exclusive) were primary BSI (89%), skin and soft tissue infection (SSTI) (25%), infective endocarditis (19%), and bone and joint infection (17%). Staphylococcus aureus accounted for 72% of index cultures, coagulase-negative Staphylococcus accounted for 18%, and Streptococcus species in 16%. Dalbavancin started a median (Q1-Q3) of 10 (6-19) days after index culture collection. The most common regimen administered was dalbavancin 1500 mg as one dose for 50% of cases. The primary outcome of composite clinical failure occurred at 12.2%, with 90-day mortality at 7.0% and 90-day BSI recurrence at 3.5%.

CONCLUSIONS

Dalbavancin may serve as a useful tool in facilitating hospital discharge in patients with Gram-positive BSI. Randomized controlled trials are anticipated to validate dalbavancin as a surrogate to current treatment standards.

Optimizing Antibiotic Therapy for Intravenous Drug Users: A Narrative Review Unraveling Pharmacokinetics/Pharmacodynamics Challenges

Intravenous drug users (IVDUs) face heightened susceptibility to life-threatening gram-positive bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA). While the standard antibiotic dosing strategies for special patients, such as obese or critically ill individuals, are known to be inadequate, raising concerns about treatment efficacy, a similar sort of understanding has not been assessed for IVDUs yet. With this in mind, this review examines the pharmacokinetic/pharmacodynamic characteristics of antibiotics commonly used against gram-positive bacteria in IVDUs. Focusing on daptomycin, vancomycin, teicoplanin, aminoglycosides, and the novel lipoglycopeptide dalbavancin, the study reveals significant pharmacokinetic variations in IVDUs, suggesting the need for personalized dosing. Concomitant opioid substitution therapy and other factors, such as malnutrition, contribute to altered pharmacokinetics/pharmacodynamics, emphasizing the importance of targeted therapeutic drug monitoring. Overall, our study calls for increased awareness among clinicians regarding the unique pharmacokinetic/pharmacodynamic challenges in IVDUs and advocates for tailored antibiotic dosing strategies to enhance treatment outcomes in this marginalized population.

Anti Gram-Positive Bacteria Activity of Synthetic Quaternary Ammonium Lipid and Its Precursor Phosphonium Salt

Organic ammonium and phosphonium salts exert excellent antimicrobial effects by interacting lethally with bacterial membranes. Particularly, quaternary ammonium lipids have demonstrated efficiency both as gene vectors and antibacterial agents. Here, aiming at finding new antibacterial devices belonging to both classes, we prepared a water-soluble quaternary ammonium lipid (6) and a phosphonium salt (1) by designing a synthetic path where 1 would be an intermediate to achieve 6. All synthesized compounds were characterized by Fourier-transform infrared spectroscopy and Nuclear Magnetic Resonance. Additionally, potentiometric titrations of NH3+ groups 1 and 6 were performed to further confirm their structure by determining their experimental molecular weight. The antibacterial activities of 1 and 6 were assessed first against a selection of multi-drug-resistant clinical isolates of both Gram-positive and Gram-negative species, observing remarkable antibacterial activity of both compounds against Gram-positive isolates of Enterococcus and Staphylococcus genus. Further investigations on a wider variety of strains of these species confirmed the remarkable antibacterial effects of 1 and 6 (MICs = 4-16 and 4-64 µg/mL, respectively), while 24 h-time-killing experiments carried out with 1 on different S. aureus isolates evidenced a bacteriostatic behavior. Moreover, both compounds 1 and 6, at the lower MIC concentration, did not show significant cytotoxic effects when exposed to HepG2 human hepatic cell lines, paving the way for their potential clinical application.

Adverse drug events associated with linezolid administration: a real-world pharmacovigilance study from 2004 to 2023 using the FAERS database

Introduction: Linezolid is an oxazolidinone antibiotic that is active against drug-resistant Gram-positive bacteria and multidrug-resistant Mycobacterium tuberculosis. Real-world studies on the safety of linezolid in large populations are lacking. This study aimed to determine the adverse events associated with linezolid in real-world settings by analyzing data from the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Methods: We retrospectively extracted reports on adverse drug events (ADEs) from the FAERS database from the first quarter of 2004 to that of 2023. By using disproportionality analysis including reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), along with the multi-item gamma Poisson shrinker (MGPS), we evaluated whether there was a significant association between linezolid and ADE. The time to onset of ADE was further analyzed in the general population and within each age, weight, reporting population, and weight subgroups. Results: A total of 11,176 reports of linezolid as the "primary suspected" drug and 263 significant adverse events of linezolid were identified, including some common adverse events such as thrombocytopenia (n = 1,139, ROR 21.98), anaemia (n = 704, ROR 7.39), and unexpected signals that were not listed on the drug label such as rhabdomyolysis (n = 90, ROR 4.33), and electrocardiogram QT prolonged (n = 73, ROR 4.07). Linezolid-induced adverse reactions involved 27 System Organ Class (SOC). Gender differences existed in ADE signals related to linezolid. The median onset time of all ADEs was 6 days, and most ADEs (n = 3,778) occurred within the first month of linezolid use but some may continue to occur even after a year of treatment (n = 46). Conclusion: This study reports the time to onset of adverse effects in detail at the levels of SOC and specific preferred term (PT). The results of our study provide valuable insights for optimizing the use of linezolid and reducing potential side effects, expected to facilitate the safe use of linezolid in clinical settings.

Impact of model-informed precision dosing in adults receiving vancomycin via continuous infusion: a randomized, controlled clinical trial

BACKGROUND

Vancomycin is a commonly prescribed antibiotic to treat gram-positive infections. The efficacy of vancomycin is known to be directly related to the pharmacokinetic/pharmacodynamic (PK/PD) index of the area under the concentration-time curve (AUC) divided by the minimal inhibitory concentration (MIC) of the pathogen. However, in most countries, steady-state plasma concentrations are used as a surrogate parameter of target AUC/MIC, but this practice has some drawbacks. Hence, direct AUC-guided monitoring of vancomycin using model-informed precision dosing (MIPD) tools has been proposed for earlier attainment of target concentrations and reducing vancomycin-related nephrotoxicity. However, solid scientific evidence for these benefits in clinical practice is still lacking. This randomized controlled trial (RCT) aims to investigate the clinical utility of MIPD dosing of vancomycin administered via continuous infusion in hospitalized adults.

METHODS

Participants from 11 wards at two Belgian hospitals are randomly allocated to the intervention group or the standard-of-care comparator group. In the intervention group, clinical pharmacists perform dose calculations using CE-labeled MIPD software and target an AUC24h of 400 to 600 mg × h/L, whereas patients in the comparator group receive standard-of-care dosing and monitoring according to the institutional guidelines. The primary endpoint is the proportion of patients reaching the target AUC24h/MIC of 400-600 between 48 and 72 h after start of vancomycin treatment. Secondary endpoints are the proportion of patients with (worsening) acute kidney injury (AKI) during and until 48 h after stop of vancomycin treatment, the proportion of patients reaching target AUC24h/MIC of 400-600 between 72 and 96 h after start of vancomycin treatment, and the proportion of time within the target AUC24h/MIC of 400-600.

DISCUSSION

This trial will clarify the propagated benefits and provide new insights into how to optimally monitor vancomycin treatment.

TRIAL REGISTRATION

EudraCT number: 2021-003670-31. Registered June 28, 2021.

CLINICALTRIALS

gov identifier: NCT05535075. Registered September 10, 2022. Protocol version 3, protocol date: April 21, 2023.

Cephalotin Versus Dicloxacillin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteraemia: A Retrospective Cohort Study

BACKGROUND

First-line treatments for methicillin-susceptible S. aureus (MSSA) bacteraemia are nafcillin, oxacillin, or cefazolin. Regional shortages of these antibiotics force clinicians to use other options like dicloxacillin and cephalotin. This study aims to describe and compare the safety and efficacy of cephalotin and dicloxacillin for the treatment of MSSA bacteraemia.

METHODS

This retrospective study was conducted in a referral centre in Mexico City. We identified MSSA isolates in blood cultures from 1 January 2012 to 31 December 2022. Patients ≥ 18 years of age, with a first episode of MSSA bacteraemia, who received cephalotin or dicloxacillin as the definitive antibiotic treatment, were included. The primary outcome was in-hospital all-cause mortality.

RESULTS

We included 202 patients, of which 48% (97/202) received cephalotin as the definitive therapy and 52% (105/202) received dicloxacillin. In-hospital all-cause mortality was 20.7% (42/202). There were no differences in all-cause in-hospital mortality between patients receiving cephalotin or dicloxacillin (20% vs. 21%, p = 0.43), nor in 30-day all-cause mortality (14% vs. 18%, p = 0.57) or 90-day all-cause mortality (24% vs. 22%, p = 0.82). No severe adverse reactions were associated with either antibiotic.

CONCLUSIONS

Cephalotin and dicloxacillin were equally effective for treating MSSA bacteraemia, and both showed an adequate safety profile.

Safety and Pharmacokinetics Following Oral or Intravenous Lefamulin in Adults With Cystic Fibrosis

PURPOSE

Methicillin-resistant Staphylococcus aureus infections are increasing in prevalence in patients with cystic fibrosis (CF) and are associated with worsening lung function and increased mortality. Lefamulin is a pleuromutilin antimicrobial approved to treat community-acquired bacterial pneumonia based on potent in vitro activity and clinical efficacy. This Phase I, open-label, randomized crossover study assessed the safety and pharmacokinetic profile of oral and intravenous (IV) lefamulin in adults with CF.

METHODS

The study comprised 2 dosing periods in which adults with CF (N = 13) received a single dose of lefamulin via a 150-mg IV infusion or 600-mg immediate-release orally administered tablet, separated by a 4- to 7-day washout period. Pharmacokinetic and safety parameters were assessed after lefamulin treatment.

FINDINGS

Single doses of lefamulin administered via oral tablet or IV infusion resulted in comparable drug exposure, and sputum analysis suggested rapid penetration of lefamulin into the lung. Comparison of the present results with those obtained from prior single-dose studies of healthy volunteers indicate no meaningful difference in the pharmacokinetic properties of lefamulin in patients with CF. Treatment-emergent adverse events were consistent with previous reports, and the majority were mild in severity.

IMPLICATIONS

These results show similar lefamulin pharmacokinetic and safety profiles between patients with CF and healthy volunteers receiving the same oral and IV doses, suggesting no need for lefamulin dose adjustment in patients with CF and indicating the potential of lefamulin as therapy for lung infections in patients with CF.

CLINICALTRIALS

gov identifier: NCT05225805.

Daptomycin and Ceftaroline Combination Therapy in Complicated Endovascular Infections Caused by Methicillin-Resistant Staphylococcus epidermidis

Background In complicated endovascular infections by methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis (MRSE), when first-line therapy with vancomycin (VAN) or daptomycin (DAP) fails, combination therapy with ceftaroline (CFT) and DAP has been shown to be a useful approach as salvage therapy for persistent MRSA bacteremia. Objectives This study aimed to describe experience with daptomycin and ceftaroline combination therapy in MRSE-complicated endovascular infections. Methods A single-center retrospective review of consecutive patients with MRSE-complicated endovascular infections treated with ≥72 hours of DAP+CFT at any time during the course of treatment, from January 1, 2016 to December 31, 2020, at Centro Hospitalar Universitário São João (CHUSJ), Porto, Portugal, was conducted. The exclusion criteria were known resistance to daptomycin or ceftaroline, total time of combination therapy <72 hours and loss to follow-up. Results We identified seven cases that matched our criteria: five endocarditis and two central venous catheter infections. Six patients switched to combination therapy due to treatment failure with first-line agents - three due to persistent bacteremia and three due to progression of infection despite negative blood cultures. Effective surgical source control took one to four weeks to occur. Three patients died during the treatment, one from progression of the disease and two due to another infection. Conclusions We consider the DAP+CFT combination therapy to be a valid and safe therapeutic choice in complicated patients, such as those with severe infection, poor functional status, and impossibility or delay of surgical source control. However, conclusions on the role of combination therapy should be careful due to the low number of patients and the several confounding factors.

Dalbavancin as a Viable Alternative for Addressing Treatment Adherence in Methicillin-Resistant Staphylococcus aureus (MRSA) Bacteremia: A Case Report

Outpatient parenteral antibiotic therapy (OPAT) aims to facilitate antibiotic treatment in non-hospital settings while minimizing hospitalization costs and infection risks. However, ensuring patient adherence, especially among socially disadvantaged groups like the homeless may be challenging. Studies indicate that increased dosing frequency negatively impacts adherence rates. Simplified dosing schedules and addressing transportation barriers are protective measures. Dalbavancin, a weekly oral antibiotic with an extended half-life, may offer a solution for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in patients with adherence challenges. We present a case of a homeless patient with MRSA bacteremia and osteomyelitis successfully treated with dalbavancin. Our case highlights the potential of dalbavancin's once-weekly dosing to improve adherence and treatment outcomes in challenging outpatient scenarios.

Empyema necessitans caused by methicillin-resistant Staphylococcus aureus: a case report and literature review

BACKGROUND

Empyema necessitans (EN) is a rare condition characterized by pleural infection with pus spreading into adjacent soft tissues. Although Mycobacterium tuberculosis and Actinomyces israelii are common causative agents, methicillin-resistant Staphylococcus aureus (MRSA) is relatively rare, but it is associated with high mortality in empyema cases. We aimed to report a unique case of EN caused by MRSA and present a literature review to better understand this rare condition.

CASE PRESENTATION

A 69-year-old man with a history of right ureteral stone presented with fever and left anterior thoracic pain. A physical examination revealed redness and swelling in the left thoracic region. Imaging studies confirmed EN with fluid accumulation around the sternocostal joint of the left first rib. MRSA was identified from blood and pleural fluid cultures. The patient received antimicrobial therapy, and a chest tube was inserted for drainage. Despite initial improvement, vertebral osteomyelitis was diagnosed on day 17. The antimicrobials were subsequently terminated after 6 weeks, but vertebral osteomyelitis recurred, and treatment was resumed and completed on day 215.

CONCLUSION

EN caused by MRSA is rare, and the literature review revealed 14 cases from human sources. Positive blood cultures were observed in 40% of cases, and metastatic infections were present in 30% of cases. Osteomyelitis was the most common type of metastatic lesion. All the patients underwent drainage. Patients with MRSA-associated EN frequently develop disseminated lesions and should therefore be carefully examined. Moreover, appropriate treatment with antibiotics and drainage is necessary for a good prognosis. Although the prognosis appeared to be favorable in our review, publication bias and treatment challenges for metastatic infections should be considered.

Predictive Value of Methicillin-Resistant Staphylococcus aureus Nasal Swab PCR Assay for MRSA Infection in Critically Ill Pediatric Patients

BACKGROUND

Critically ill pediatric patients are frequently initiated methicillin-resistant Staphylococcus aureus (MRSA) active antibiotics during infection evaluation even though MRSA infections are rare in many patient populations. The MRSA nasal swab polymerase chain reaction assay (MRSA-NS-PCR) is a test that has been shown to have a high negative predictive value (NPV) for MRSA infection in adults. This study evaluated the diagnostic test characteristics of the MRSA-NS-PCR in predicting the presence of MRSA infection in critically ill pediatric patients.

STUDY DESIGN

A retrospective cohort study was performed in a 44-bed pediatric intensive care unit (PICU) between 2013 and 2017. 3860 pediatric patients (54% male, median age 4 years [IQR 1-11 years]) admitted to the PICU who met pediatric systemic inflammatory response syndrome (pSIRS) criteria, were screened with a MRSA-NS-PCR, and had cultures obtained within seven days of MRSA-NS-PCR collection were included. Predictive values and post-test probabilities of the MRSA-NS-PCR for MRSA infection were calculated.

RESULTS

MRSA-NS-PCR was positive in 8.6% of patients. MRSA infection was identified in 40 patients, equaling an incidence rate of 2 per 1000 patient days. The MRSA-NS-PCR demonstrated a positive predictive value (PPV) of 9.7%, a NPV of 99.8%, and a post-test probability for a negative test of 0.2% for MRSA infection.

CONCLUSIONS

The MRSA-NS-PCR has a poor PPV but a high NPV for MRSA infection in PICU patients when the incidence of MRSA infection is low. Creation of protocols to guide antimicrobial selection based on MRSA-NS-PCR results may lead to improved antimicrobial stewardship and significant risk reduction.

Antimicrobial Resistance Patterns of Staphylococcus Aureus Isolated at a General Hospital in Vietnam Between 2014 and 2021

Purpose

Staphylococcus aureus is a commensal bacteria species that can cause various illnesses, from mild skin infections to severe diseases, such as bacteremia. The distribution and antimicrobial resistance (AMR) pattern of S. aureus varies by population, time, geographic location, and hospital wards. In this study, we elucidated the epidemiology and AMR patterns of S. aureus isolated from a general hospital in Vietnam.

Methods

This was a cross-sectional study. Data on all S. aureus infections from 2014 to 2021 were collected from the Microbiology department of Military Hospital 103, Vietnam. Only the first isolation from each kind of specimen from a particular patient was analyzed using the Cochran-Armitage and chi-square tests.

Results

A total of 1130 individuals were diagnosed as S. aureus infection. Among them, 1087 strains were tested for AMR features. Most patients with S. aureus infection were in the age group of 41-65 years (39.82%). S. aureus isolates were predominant in the surgery wards, and pus specimens were the most common source of isolates (50.62%). S. aureus was most resistant to azithromycin (82.28%), erythromycin (82.82%), and clindamycin (82.32%) and least resistant to teicoplanin (0.0%), tigecycline (0.16%), quinupristin-dalfopristin (0.43%), linezolid (0.62%), and vancomycin (2.92%). Methicillin-resistant S. aureus (MRSA) and multidrug-resistant (MDR) S. aureus were prevalent, accounting for 73.02% and 60.90% of the total strains respectively, and the strains isolated from the intensive care unit (ICU) had the highest percentage of multidrug resistance (77.78%) among the wards.

Conclusion

These findings highlight the urgent need for continuous AMR surveillance and updated treatment guidelines, particularly considering high resistance in MRSA, MDR strains, and ICU isolates. Future research focusing on specific resistant populations and potential intervention strategies is crucial to combat this rising threat.

Oritavancin as sequential therapy for Gram-positive bloodstream infections

BACKGROUND

Oritavancin, a long-acting lipoglycopeptide approved for use in acute bacterial skin and skin structure infections, has limited data evaluating use in serious infections due to Gram-positive organisms. We aimed to assess the effectiveness and safety of oritavancin for consolidative treatment of Gram-positive bloodstream infections (BSI), including infective endocarditis (IE).

METHODS

We conducted a retrospective cohort study evaluating adult patients admitted to University of Colorado Hospital from March 2016 to January 2022 who received ≥ 1 oritavancin dose for treatment of Gram-positive BSI. Patients were excluded if the index culture was drawn at an outside facility or were > 89 years of age. The primary outcome was a 90-day composite failure (clinical or microbiological failure) in those with 90-day follow-up. Secondary outcomes included individual components of the primary outcome, acute kidney injury (AKI), infusion-related reactions (IRR), and institutional cost avoidance.

RESULTS

Overall, 72 patients were included. Mean ± SD age was 54 ± 16 years, 61% were male, and 10% had IE. Organisms most commonly causing BSI were Staphylococcus aureus (68%, 17% methicillin-resistant), followed by Streptococcus spp. (26%), and Enterococcus spp. (10%). Patients received standard-of-care antibiotics before oritavancin for a median (IQR) of 11 (5-17) days. Composite failure in the clinically evaluable population (n = 64) at 90-days occurred in 14% and was composed of clinical and microbiological failure, which occurred in 14% and 5% of patients, respectively. Three patients (4%) experienced AKI after oritavancin, and two (3%) experienced an IRR. Oritavancin utilization resulted in earlier discharge for 94% of patients corresponding to an institutional cost-avoidance of $3,055,804 (mean $44,938/patient) from 1,102 hospital days saved (mean 16 days/patient).

CONCLUSIONS

The use of oritavancin may be an effective sequential therapy for Gram-positive BSI to facilitate early discharge resulting in institutional cost avoidance.

Biofilm Producing Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in Humans: Clinical Implications and Management

Since its initial description in the 1960s, methicillin-resistant Staphylococcus aureus (MRSA) has developed multiple mechanisms for antimicrobial resistance and evading the immune system, including biofilm production. MRSA is now a widespread pathogen, causing a spectrum of infections ranging from superficial skin issues to severe conditions like osteoarticular infections and endocarditis, leading to high morbidity and mortality. Biofilm production is a key aspect of MRSA's ability to invade, spread, and resist antimicrobial treatments. Environmental factors, such as suboptimal antibiotics, pH, temperature, and tissue oxygen levels, enhance biofilm formation. Biofilms are intricate bacterial structures with dense organisms embedded in polysaccharides, promoting their resilience. The process involves stages of attachment, expansion, maturation, and eventually disassembly or dispersion. MRSA's biofilm formation has a complex molecular foundation, involving genes like icaADBC, fnbA, fnbB, clfA, clfB, atl, agr, sarA, sarZ, sigB, sarX, psm, icaR, and srtA. Recognizing pivotal genes for biofilm formation has led to potential therapeutic strategies targeting elemental and enzymatic properties to combat MRSA biofilms. This review provides a practical approach for healthcare practitioners, addressing biofilm pathogenesis, disease spectrum, and management guidelines, including advances in treatment. Effective management involves appropriate antimicrobial therapy, surgical interventions, foreign body removal, and robust infection control practices to curtail spread within healthcare environments.

Implementation of a pharmacy-driven rapid bacteremia response program

PURPOSE

This report describes a comprehensive pharmacy-driven rapid bacteremia response program.

SUMMARY

This novel program positioned the pharmacy department at a large, community health system to receive and respond to critical microbiologic diagnostic testing results, 24/7/365. The program empowered pharmacists to provide centralized, comprehensive care including assessing blood culture Gram stain results, adjusting antibiotic therapy per protocol, ordering repeat blood cultures, analyzing and interpreting rapid molecular diagnostic test results, placing orders for contact isolation, and communicating antibiotic recommendations to the treatment team. In the first year after program implementation, 2,282 blood culture Gram stains and 2,046 rapid diagnostic test results were called in to the pharmacy department. The program reduced the median time to effective therapy in patients who did not already have active antimicrobial orders from over 10 hours to less than 1 hour. Based on the Gram stain results, antibiotics were started per protocol in 34.2% of patients. Based on the rapid molecular diagnostic test results, adjustments were made to antibiotic regimens in 55.7% of cases after discussion with a provider. Of these adjustments, 39.9% were for escalation of antibiotics and 37.7% were for de-escalation of antibiotics.

CONCLUSION

By expanding the scope of pharmacy practice, barriers to optimizing clinical care were overcome.

Clinical application of vancomycin TDM in ventilated patients with gastrointestinal cancer: a propensity-matched analysis

BACKGROUND

Therapeutic drug monitoring (TDM) of vancomycin is widely recommended for clinical treatment. Due to the complexity of 24-h area under the curve (AUC) guided vancomycin monitoring in clinical practice, the vancomycin trough level remains the most common and practical method. The purpose of this study was designed to investigate the differences in the safety and efficacies of vancomycin TDM based on the two different monitoring methods, and further explore the clinical application of trough-guided vancomycin monitoring in patients with gastrointestinal cancer requiring mechanical ventilation.

METHODS

We included a total of 78 gastrointestinal cancer patients who required mechanical ventilation due to various diseases. All patients included in this study were aged 18 years or older and were treated with intravenous vancomycin therapy for more than 2 days due to documented or suspected Gram-positive bacterial infections, and have at least one available vancomycin plasma concentration. First, we compared the safety and efficacies of vancomycin TDM based on different monitoring methods as trough-guided monitoring or AUC-guided monitoring. Then, based on whether the initial vancomycin concentration achieving the target trough concentration (less than 48 h), patients were divided into early and delayed groups, and the clinical factors were compared between them. The primary endpoints include the incidence of new-onset acute kidney injury (AKI) or renal replacement therapy (RRT), clinical success rate and 28-day all-cause mortality. Finally, the overall relationship between trough concentration and potential covariates is screened by univariate and multivariate analysis to explore potential information covariates.

RESULTS

The research revealed that patients with gastrointestinal cancer exhibited significantly lower initial vancomycin trough concentrations (median [interquartile range (IQR)]: 6.90[5.28-11.20] mg/L). And there were no statistically significant differences in the safety and efficacies of vancomycin TDM based on the two different monitoring methods for the primary endpoint. Moreover, base on trough-guided vancomycin monitoring, the early group demonstrated a notably shorter duration of mechanical ventilation compared with the delayed group (χ2 = 4.532; p < 0.05; Fig. 2E). Propensity score weighting further confirmed that the duration of mechanical ventilation (χ2 = 6.607; p < 0.05; Fig. 2F) and duration of vasoactive agent (χ2 = 6.106; p < 0.05; Fig. 2D) were significantly shorter in the early group compared with delayed group. Multivariate regression analysis revealed that Cystatin C (Cys-C) was the most important variable for vancomycin target trough achievement (odds ratio, 5.274; 95% CI, 1.780 to 15.627; p = 0.003).

CONCLUSIONS

Trough-guided vancomycin monitoring is a simple and effective marker of TDM for ventilated patients with gastrointestinal cancer. Timely achievement of target trough concentrations for vancomycin can improve partial clinical outcomes in Gram-positive bacterial infections. Cys-C level is a potentially valuable parameter for predicting the vancomycin concentration.

Potential of Flavonoids as Promising Phytotherapeutic Agents to Combat Multidrug-Resistant Infections

BACKGROUND

Considering the limited number of current effective treatments, Multidrug- Resistant (MDR) illnesses have grown to be a serious concern to public health. It has become necessary to look for new antimicrobial drugs because of the emergence of resistance to numerous kinds of antibiotics. The use of flavonoids is one phytotherapeutic strategy that has been researched as a potential remedy for this issue. Secondary plant compounds called flavonoids have been found to have an antibacterial effect against resistant microorganisms.

OBJECTIVE

This review seeks to give readers a glimpse into contemporary studies on flavonoids' potential to fight MDR infections.

METHODS

A systematic search was conducted on electronic databases (PubMed, Scopus, and Google Scholar) using relevant keywords such as flavonoids, MDR infections, antimicrobial activity, and resistance microbes. Studies that investigated the antimicrobial activity of flavonoids against resistant microbes were included in this review.

RESULTS

Most research found that flavonoids have antibacterial efficacy against resistant microorganisms, and some also showed that they have synergistic benefits with traditional antibiotics. The flavonoids quercetin, kaempferol, apigenin, and luteolin were the most often investigated ones. According to research, flavonoids affect microbial gene expression, inhibit microbial enzymes, and disrupt the integrity of microbial cell membranes. Additionally, a few studies have noted the flavonoids' low toxicity and safety.

CONCLUSION

For the treatment of infections that are resistant to many drugs, flavonoids constitute a promising class of phytotherapeutic agents. To develop flavonoid-based treatment methods for treating MDR illnesses and assess the potential of flavonoids as adjuvants to conventional antimicrobial drugs, more study is required.

It's Not a Spider Bite-It's MRSA!

Although there is an increased awareness of community-acquired methicillin-resistant Staphylococcus aureus (MRSA), there remains a bias of the public and health-care workers to blame spiders as a cause of skin and soft tissue infection when there is no valid incriminated evidence for this assumption. MRSA is a formidable infection and remains a threat to human health. Recognition and proper treatment by practitioners remain of utmost importance to improve patient outcomes.

A Study of Impact of Fixed-Dose Albumin Infusion on Outcome in Patients With Cirrhosis and Infection: A Randomized Open-label Clinical Trial

Background and aim

Antibiotics and albumin infusion constitute the standard of treatment in patients with decompensated cirrhosis who have spontaneous bacterial peritonitis (SBP). Recent studies have also shown that the use of albumin in patients with advanced liver disease who have infections other than SBP leads to the resolution of acute and chronic liver failure and prevents the development of nosocomial infections. The recommended dose of albumin for these patients is out of reach for many in resource-limited settings like India. The evidence for this recommendation is also scarce. This study aimed to assess the efficacy of a lower dose of albumin infusion in addition to antibiotics on short-term mortality and morbidity in patients with cirrhosis and infections.

Patients and methods

A prospective, open-label, randomized control study was performed. Consecutive patients with cirrhosis and infections were randomized in a 2:1 ratio into two groups: group A (116) and group B (58) patients. In addition to antibiotics and standard medical therapy, group A was given albumin in a dose of 20 g/day for five days, and group B was given the recommended dose (1.5 g/kg/body weight and 1 g/kg body weight on days one and three, respectively). The primary outcome was in-hospital mortality. Secondary outcomes were improvements in clinical and laboratory parameters.

Results

Except for etiology, all the baseline clinical and laboratory variables in both groups were comparable. The in-hospital mortality in groups A and B was (11 [10.67%] vs. 6 [10.09%], (P = 0.965). The duration of hospitalization, 30-day mortality, improvement in shock and sensorium, and absolute improvements in serum creatinine, international normalized ratio (INR), and serum bilirubin were also comparable in both groups.

Conclusion

Low-dose albumin infusion in patients with cirrhosis and infections can have the same results as standard-dose albumin and can be used in resource-limited situations.

Clinical trial registration number

CTRI/2020/03/023794.

Optimal Blood Sampling Time for Area under the Concentration-Time Curve Estimation of Vancomycin by Assessing the Accuracy of Four Bayesian Software

Effective blood sampling times, beyond trough and peak levels, have not been determined for estimating vancomycin's area under the concentration-time curve (AUC) using the Bayesian software. The aim of this study was to evaluate the accuracy of AUC estimation at different blood sampling times during the same dosing interval at steady state utilizing data from a prior phase I trial of vancomycin. Six healthy adult participants were sampled following intravenous administration of 1 g vancomycin for 1.5 h every 12 h. The AUC was estimated using four software packages and four population pharmacokinetic models. Accuracy was assessed using bias (difference between the estimated and reference AUC) and imprecision (absolute percentage difference between the estimated and reference AUC). The accuracy varied with the sampling time. The optimal two-point sampling times were determined to be 2.5 and 5.5 h post-injection using software packages for EasyTDM, Practical AUC-guided therapeutic drug monitoring (TDM), and Anti-MRSA Agents TDM Analysis Software (incorporating Rodvold, Yamamoto, and Yasuhara models). In these estimations, the mean bias (range, -1.7 to 9.5 µg·h/mL) was unbiased and the mean imprecision (range, -3.0% to 5.0%) was precise. The optimal one-point sampling time was 5.5 h post-injection for Anti-MRSA Agents TDM Analysis Software, which incorporated the Yamamoto and Yasuhara models. In conclusion, optimal blood sampling times may vary depending on the software and model used. Our findings suggest that identifying specific sampling times could improve the efficacy of TDM in clinical practice.

Safety and effectiveness of fifth generation cephalosporins for the treatment of methicillin-resistant staphylococcus aureus bloodstream infections: a narrative review exploring past, present, and future

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) is a major issue in healthcare, since it is often associated with endocarditis or deep site foci. Relevant morbidity and mortality associated with MRSA-BSIs forced the development of new antibiotic strategies; in particular, this review will focus the attention on fifth-generation cephalosporins (ceftaroline/ceftobiprole), that are the only ß-lactams active against MRSA.

AREAS COVERED

The review discusses the available randomized controlled trials and real-world observational studies conducted on safety and effectiveness of ceftaroline/ceftobiprole for the treatment of MRSA-BSIs. Finally, a proposal of MRSA-BSI treatment flowchart, based on fifth-generation cephalosporins, is described.

EXPERT OPINION

The use of anti-MRSA cephalosporins is an acceptable choice either in monotherapy or combination therapy for the treatment of MRSA-BSIs due to their relevant effectiveness and safety. Particularly, their use may be advisable in combination therapy in case of severe infections (including endocarditis or persistent bacteriemia) or in monotherapy in subjects at higher risk of drugs-induced toxicity with older regimens. On the contrary, caution should be taken in case of suspected/ascertained central nervous system infections due to inconsistent data regarding penetration of these drugs in cerebrospinal fluid and brain tissues.

Model-Informed Precision Dosing Improves Outcomes in Patients Receiving Vancomycin for Gram-Positive Infections

Background

Consensus guidelines for dosing and monitoring of vancomycin recommend collection of 2 serum concentrations to estimate an area under the curve/minimum inhibitory concentration ratio (AUC/MIC). Use of Bayesian software for AUC estimation and model-informed precision dosing (MIPD) enables pre-steady state therapeutic drug monitoring using a single serum concentration; however, data supporting this approach are limited.

Methods

Adult patients with culture-proven gram-positive infections treated with vancomycin ≥72 hours receiving either trough-guided or AUC-guided therapy were included in this retrospective study. AUC-guided therapy was provided using MIPD and single-concentration monitoring. Treatment success, vancomycin-associated acute kidney injury (VA-AKI), and inpatient mortality were compared using a desirability of outcome ranking analysis. The most desirable outcome was survival with treatment success and no VA-AKI, and the least desirable outcome was death.

Results

The study population (N = 300) was comprised of an equal number of patients receiving AUC-guided or trough-guided therapy. More patients experienced the most desirable outcome in the AUC-guided group compared to the trough-guided group (58.7% vs 46.7%, P = .037). Rates of VA-AKI were lower (21.3% vs 32.0%, P = .037) and median hospital length of stay was shorter (10 days [interquartile range {IQR}, 8-20] vs 12 days [IQR, 8-25]; P = .025) among patients receiving AUC-guided therapy.

Conclusions

AUC-guided vancomycin therapy using MIPD and single-concentration monitoring improved outcomes in patients with culture-proven gram-positive infections. Safety was improved with reduced incidence of VA-AKI, and no concerns for reduced efficacy were observed. Moreover, MIPD allowed for earlier assessment of AUC target attainment and greater flexibility in the collection of serum vancomycin concentrations.

[Guideline-conform treatment of sepsis]

The time to administration of broad-spectrum antibiotics and (secondarily) to the initiation of hemodynamic stabilization are the most important factors influencing survival of patients with sepsis and septic shock; however, the basic prerequisite for the initiation of an adequate treatment is that a suspected diagnosis of sepsis is made first. Therefore, the treatment of sepsis, even before it has begun, is an interdisciplinary and interprofessional task. This article provides an overview of the current state of the art in sepsis treatment and points towards new evidence that has the potential to change guideline recommendations in the coming years. In summary, the following points are critical: (1) sepsis must be diagnosed as soon as possible and the implementation of a source control intervention (in case of a controllable source) has to be implemented as soon as (logistically) possible. (2) In general, intravenous broad-spectrum antibiotics should be given within the first hour after diagnosis if sepsis or septic shock is suspected. In organ dysfunction without shock, where sepsis is a possible but unlikely cause, the results of focused advanced diagnostics should be awaited before a decision to give broad-spectrum antibiotics is made. If it is not clear within 3 h whether sepsis is the cause, broad-spectrum antibiotics should be given when in doubt. Administer beta-lactam antibiotics as a prolonged (or if therapeutic drug monitoring is available, continuous) infusion after an initial loading dose. (3) Combination treatment with two agents for one pathogen group should remain the exception (e.g. multidrug-resistant gram-negative pathogens). (4) In the case of doubt, the duration of anti-infective treatment should rather be shorter than longer. Procalcitonin can support the clinical decision to stop (not to start!) antibiotic treatment! (5) For fluid treatment, if hypoperfusion is present, the first (approximately) 2L (30 ml/kg BW) of crystalloid solution is usually safe and indicated. After that, the rule is: less is more! Any further fluid administration should be carefully weighed up with the help of dynamic parameters, the patient's clinical condition and echo(cardio)graphy.

Infantile orbital abscess caused by methicillin-resistant Staphylococcus aureus: a case report and literature review

Objective

To report and review infantile orbital abscess caused by methicillin-resistant Staphylococcus aureus (MRSA).

Methods

We report a case of MRSA-induced infantile orbital abscess accompanied by sepsis, pneumonia, and purulent meningitis. We systematically review cases of MRSA-induced infantile orbital abscess published in PubMed, Web of Science and ScienceDirect until April 2023.

Results

We reviewed 14 patients [our patient + 13 patients (10 papers) identified via literature searches]. There were nine boys and five girls; nine neonates and five older infants; and 8 full-term births and 1 preterm birth. The gestational age at birth was unknown for five infants. The right and left orbits were affected in 10 and 4 patients, respectively. The clinical presentation included periorbital soft-tissue edema or redness (11 patients), fever (7 patients), exophthalmos (10 patients), limited eye movement (4 patients), purulent eye secretions (2 patients), and skin abscess and convulsion (1 patient each). The source of infection was sinusitis (8 patients), vertical transmission, gingivitis, dacryocystitis, upper respiratory tract infection (1 patient each), and unknown (2 patients). MRSA was detected in blood (6 patients) or pus culture (8 patients). Vancomycin or linezolid were used for 11 patients; corticosteroids were administered to only 1 patient. Surgical drainage was performed for 13 infants (external drainage, 11 patients; endoscopic drainage, 2 patients). Two patients initially had pulmonary and intracranial infections. Except for one patient with neurological dysfunction at discharge, all other infants had no sequelae or complications.

Conclusion

Early aggressive anti-infective treatment and timely drainage are essential for managing MRSA-induced infantile orbital abscess.

Pinus koraiensis Essential Oil Attenuates the Pathogenicity of Superbacteria by Suppressing Virulence Gene Expression

In the quest to combat infections attributable to antibiotic-resistant superbacteria, an essential oil derived from the needles of Pinus koraiensis Sieb. et Zucc. (PKEO) has emerged as a promising solution. In this study, we demonstrate that PKEO can be used to inhibit the growth, glucose metabolite acidogenicity, and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Quantitative PCR analysis provided direct evidence that PKEO reduces the mRNA expression of the accessory gene regulator A (agrA) and staphylococcal accessory regulator A (sarA), thereby indicating its inhibitory effect on pathogenic regulatory genes. Chromatographic analyses of PKEO identified terpene hydrocarbons as prominent essential oil constituents. These compounds, notably α-pinene, limonene, and β-caryophyllene, have been established to have antimicrobial properties. Our findings indicate that an oil derived from P. koraiensis can effectively combat antibiotic-resistant strains by disrupting the pathogenicity regulatory system, thereby establishing PKEO as a promising candidate for the treatment of MRSA infections.

Development of Oxadiazolone Activity-Based Probes Targeting FphE for Specific Detection of S. aureus Infections

Staphylococcus aureus is a major human pathogen responsible for a wide range of systemic infections. Since its propensity to form biofilms in vivo poses formidable challenges for both detection and treatment, tools that can be used to specifically image S. aureus biofilms are highly valuable for clinical management. Here we describe the development of oxadiazolonebased activity-based probes to target the S. aureus-specific serine hydrolase FphE. Because this enzyme lacks homologs in other bacteria, it is an ideal target for selective imaging of S. aureus infections. Using X-ray crystallography, direct cell labeling and mouse models of infection we demonstrate that oxadiazolone-based probes enable specific labeling of S. aureus bacteria through the direct covalent modification of the FphE active site serine. These results demonstrate the utility of the oxadizolone electrophile for activity-based probes (ABPs) and validate FphE as a target for development of imaging contrast agents for the rapid detection of S. aureus infections.

Optimizing transitions of care antimicrobial prescribing at a community teaching hospital

Objective

Antibiotic prescribing at hospital discharge is an important focus for antimicrobial stewardship efforts. This study set out to determine the impact of a pharmacist-led intervention at hospital discharge on appropriate antimicrobial prescribing.

Design

This was a pre-/post-study evaluating the impact of a pharmacist-led review on antibiotic prescribing at hospital discharge. Pharmacists evaluated antibiotic prescriptions at discharge for appropriate duration, spectrum of activity, frequency, and strength of dose. Each of these criteria needed to be met for an antibiotic regimen to be considered appropriate.

Setting

Moses Cone Hospital is a 535-bed community teaching hospital in Greensboro, North Carolina.

Patients or Participants

Patients ≥18 years of age discharged from the hospital with an antibiotic prescription were included. Exclusion criteria included patients discharged against medical advice, discharged to a skilled nursing facility, or prescribed indefinite prophylactic antimicrobial therapy.

Interventions

A review of patients discharged with antibiotics in 2020 was performed. Patients discharged with antibiotic prescriptions from January 2021 to April 2022 were evaluated prior to discharge by pharmacists. The pharmacist made recommendations to providers based on their evaluations.

Results

162 retrospective patients were screened, and 136 patients were screened at discharge from the hospital in the prospective cohort. 76/162 (47%) retrospective patients received appropriate antibiotic therapy at discharge, while 92/136 (68%) of prospective patients received appropriate discharge therapy (p = 0.001).

Conclusions

In this study examining the efficacy of stewardship pharmacist intervention at hospital discharge, pharmacist review and recommendations were associated with an increased rate of appropriate antimicrobial prescribing.

Ethics statement

This study was conducted under the approval of the Institutional Review Board of the Moses H. Cone Health System. The approval protocol number was 1483117-1 and took effect on September 2nd, 2019. As the research was either retrospective in nature or part of the standard of care recommendations, the project was granted expedited review.

Forward or Backward: Lessons Learned from Small Molecule Drugs Approved by FDA from 2012 to 2022

At every juncture in history, the design and identification of new drugs pose significant challenges. To gain valuable insights for future drug development, we conducted a detailed analysis of New Molecular Entitiy (NME) approved by the Food and Drug Administration (FDA) from 2012 to 2022 and focused on the analysis of first-in-class (FIC) small-molecules from a perspective of a medicinal chemist. We compared the change of numbers between all the FDA-approved NMEs and FIC, which could be more visual to analyze the changing trend of FIC. To get a more visual change of molecular physical properties, we computed the annual average trends in molecular weight for FIC across various therapeutic fields. Furthermore, we consolidated essential information into three comprehensive databases, which covered the indications, canonical SMILES, structural formula, research and development (R&D) institutions, molecular weight, calculated LogP (CLogP), and route of administration on all the small-molecule pharmaceutical. Through the analysis of the database of 11 years of approvals, we forecast the development trend of NME approval in the future.

Clinical reasoning for performance of transesophageal echocardiography in veterans with Staphylococcus aureus bacteremia

This study examined physicians' reasoning about obtaining transesophageal echocardiography (TEE) in cases of Staphylococcus aureus bacteremia (SAB). In 221 cases of SAB over 5 years, the most common reasons for not performing TEE were clinical response to antibiotics, negative TTE results, and the expectation that TEE would not change management.

Serum concentration of continuously administered vancomycin influences efficacy and safety in critically ill adults: a systematic review

OBJECTIVES

Vancomycin is used to treat Gram-positive infections in critically ill adults. For vancomycin administered by continuous infusion (CI), various target ranges have been used, ranging from 15-20 mg/L to 30-40 mg/L. This systematic literature review was conducted to investigate the impact of steady-state serum concentration (Css) of CI on safety and efficacy of therapy in critically ill adults.

METHODS

Relevant literature was identified by searching two electronic databases (PubMed, Cochrane Library) and Google Scholar from inception until July 2023, focusing on studies reporting measured Css and treatment outcomes (e.g. mortality, nephrotoxicity) with CI. Due to study heterogeneity, a narrative synthesis of the evidence was performed.

RESULTS

Twenty-one publications were included with a total of 2949 patients. Mortality was higher (two studies, n = 388 patients) and clinical cure was lower (one study, n = 40 patients) with Css < 15 mg/L measured 24 h after initiation of CI (C24). An adequate loading dose appeared most important for maintaining higher C24. Generally, higher Css was associated with higher rates of acute kidney injury (AKI) (15 studies, n = 2331 patients). It was calculated that Css < 25 mg/L (versus ≥25 mg/L) was preferable for reducing nephrotoxicity (three studies, n = 515 patients).

CONCLUSIONS

Despite sparse data availability, the target range of 15-25 mg/L in CI may increase clinical cure and reduce mortality and AKI. In future research, vancomycin Css cohorts should be formed to allow evaluation of the impact of Css of CI on treatment outcomes.

Correlation of Calculated Vancomycin Trough Concentrations and Exposure: A Monte Carlo Simulation

BACKGROUND

Current recommendations are to dose vancomycin to target 24-hour area under the curve (AUC) of 400-600 mg·h/L to optimize efficacy and safety. Limited data support AUC monitoring, and some centers continue to use trough concentrations. A target of 10-20 mg/L has been proposed to reduce nephrotoxicity risk.

OBJECTIVE

To use previously published pharmacokinetic equations in a Monte Carlo simulation relating AUC exposure to trough concentrations when targeting an AUC between 400 and 600 mg·h/L.

METHODS

Previously published pharmacokinetic data were used as input parameters for a Monte Carlo simulation using previously published formulae to correlate AUC to simulated trough concentrations. Pharmacokinetic parameters were assumed to occur in a normal distribution pattern. We excluded irrelevant simulated cases. Maintenance doses of 15 mg/kg were rounded to the nearest 250 mg. Calculated trough concentrations for AUCs of both 400 and 600 mg·h/L were evaluated in each simulation.

RESULTS

A total of 10 000 Monte Carlo simulations were performed. Targeting an AUC of 400 mg·h/L resulted in a mean trough concentration of 10.3 ± 0.8 mg/L. Targeting an AUC of 600 mg·h/L resulted in a mean trough concentration of 15.4 ± 1.2 mg/L.

CONCLUSION AND RELEVANCE

We demonstrate that a lower trough concentration range may be supported by an AUC of 400-600 mg·h/L, which may reduce risk and rates of nephrotoxicity without compromising previously established efficacious target trough concentrations.

Amino acid substitutions in the region between RpoB clusters II and III on rifampin susceptibility in Haemophilus influenzae

BACKGROUND

Rifampin is a potent chemoprophylactic antibiotic for Haemophilus influenzae infection, and the resistance rate in H. influenzae is low. In this study, we assessed rifampin resistance-related genetic variations in H. influenzae.

METHODS

Rifampin susceptibility testing and whole-genome sequencing were performed in 51 H. influenzae isolates. Variations associated with rifampin resistance were identified using Fisher's exact tests. Functional assays were performed to evaluate the effect of RpoB substitutions on rifampin susceptibility.

RESULTS

Using the genome of the Rd KW20 H. influenzae strain as the reference, we detected 40 genetic variations in rpoB, which resulted in 39 deduced amino acid substitutions among the isolates. Isolate A0586 was resistant to rifampin, with a minimum inhibitory concentration (MIC) = 8 μg/mL. Phylogenetic analyses revealed that the RpoB sequence of isolate A0586 was distinct from other isolates. Five substitutions, including H526N located in cluster I and L623F, R628C, L645F, and L672F in the region between clusters II and III, were unique to isolate A0586. In two rifampin-susceptible H. influenzae isolates, RpoB-H526N alone and in combination with RpoB-L672F increased the MICs of rifampin to 4 and 8 μg/mL, respectively. RpoB-L672F did not affect cell growth and transcription in H. influenzae isolates. No amino acid substitutions in the AcrAB-TolC efflux pump or outer membrane proteins were found to be associated with rifampin resistance in H. influenzae.

CONCLUSIONS

Our findings indicate that L672F substitution in the region between RpoB clusters II and III has an aggravating effect on rifampin resistance in H. influenzae.

Management of Children With Uncomplicated Cellulitis in Emergency and Hospital Settings

OBJECTIVE

The aim of the study is to establish consensus recommendations on features used to determine the route of antibiotic administration and disposition for children with uncomplicated cellulitis.

METHODS

Modified Delphi methodology was performed with 2 rounds of confidential surveys of Emergency medicine and hospital medicine (HM) providers at Lurie Children's Hospital to assess cellulitis management in children (ages 6 months-18 years) without signs of sepsis or abscess formation. Using a 9-point Likert scale, emergency medicine providers ranked features by perceived level of importance when deciding initial antibiotic route and HM providers ranked features on importance when transitioning to oral antibiotics. Responses were grouped as not important (1-3), neutral (4-6), and important (7-9) and re-evaluated in the second round to reach consensus, defined as ≥70% agreement.

RESULTS

Emergency medicine providers (n = 17) reached consensus on 15 of 16 features (93.8%), 10 deemed important. Participants reached greatest consensus (100%) on fevers/chills, lymphangitis, and functional impairment as considerations for initiating intravenous antibiotics. HM providers (n = 15) reached consensus on 9 of 11 factors (81.8%), with 7 considered important when deciding on readiness for oral antibiotics. Providers indicated that stability, rather than reduction, of erythematous margins is sufficient to consider transition and de-escalation of therapy at less than 24 hours if all other clinical improvement criteria are met.

CONCLUSIONS

This study achieved consensus on important features for treatment and disposition of children with uncomplicated cellulitis in both emergency and inpatient contexts. These features have the potential to aid in decision making and improve standardization of clinical practice.

Echinacoside, a promising sortase A inhibitor, combined with vancomycin against murine models of MRSA-induced pneumonia

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacterium responsible for a range of severe infections, such as skin infections, bacteremia, and pneumonia. Due to its antibiotic-resistant nature, current research focuses on targeting its virulence factors. Sortase A (SrtA) is a transpeptidase that anchors surface proteins to the bacterial cell wall and is involved in adhesion and invasion to host cells. Through fluorescence resonance energy transfer (FRET), we identified echinacoside (ECH), a natural polyphenol, as a potential SrtA inhibitor with an IC50 of 38.42 μM in vitro. It was demonstrated that ECH inhibited SrtA-mediated S. aureus fibrinogen binding, surface protein A anchoring, and biofilm formation. The fluorescence quenching assay determined the binding mode of ECH to SrtA and calculated the KA-binding constant of 3.09 × 105 L/mol, demonstrating the direct interaction between the two molecules. Molecular dynamics simulations revealed that ECH-SrtA interactions occurred primarily at the binding sites of A92G, A104G, V168A, G192A, and R197A. Importantly, the combination of ECH and vancomycin offered protection against murine models of MRSA-induced pneumonia. Therefore, ECH may serve as a potential antivirulence agent against S. aureus infections, either alone or in combination with vancomycin.

Contemporary Management of Staphylococcus aureus Bacteremia-Controversies in Clinical Practice

Staphylococcus aureus bacteremia (SAB) carries a high risk for excess morbidity and mortality. Despite its prevalence, significant practice variation continues to permeate clinical management of this syndrome. Since the publication of the 2011 Infectious Diseases Society of America (IDSA) guidelines on management of methicillin-resistant Staphylococcus aureus infections, the field of SAB has evolved with the emergence of newer diagnostic strategies and therapeutic options. In this review, we seek to provide a comprehensive overview of the evaluation and management of SAB, with special focus on areas where the highest level of evidence is lacking to inform best practices.

New Pyrazole-Clubbed Pyrimidine or Pyrazoline Hybrids as Anti-Methicillin-Resistant Staphylococcus aureus Agents: Design, Synthesis, In Vitro and In Vivo Evaluation, and Molecular Modeling Simulation

Two hybrid series of pyrazole-clubbed pyrimidines 5a-c and pyrazole-clubbed pyrazoline compounds 6a,b and 7 were designed as attractive scaffolds to be investigated in vitro and in vivo for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. From the results of the in vitro antibacterial screening, compound 5c showed excellent activity (minimal inhibitory concentration, MIC = 521 μM) when compared with that of the reference antibiotic levofloxacin (MIC = 346 μM). The inhibition of the target dihydrofolate reductase (DHFR) enzyme by compounds 4 and 5a-c (IC50 = 5.00 ± 0.23, 4.20 ± 0.20, 4.10 ± 0.19, and 4.00 ± 0.18 μM, respectively) was found to be better than the reference drug trimethoprim (IC50 = 5.54 ± 0.28 μM). Molecular modeling simulation results have justified the order of activity of all the newly synthesized compounds as DHFR enzyme inhibitors, and compound 5c exhibited the best binding profile (-13.6169386 kcal/mol). Hence, the most potent inhibitor of the DHFR enzyme, 5c, was chosen to be evaluated in vivo for its activity in treating MRSA-induced keratitis in rats and that, in turn, significantly (P < 0.0001) reduced infection in rats when compared to MRSA-treated group results.

Methicillin Resistance Increased the Risk of Treatment Failure in Native Joint Septic Arthritis Caused by Staphylococcus aureus

This study aimed to compare clinical characteristics and outcomes in patients with native joint septic arthritis (NJSA) due to methicillin-resistant Staphylococcus aureus (MRSA) in comparison to methicillin-sensitive S. aureus (MSSA) and identify treatment failure risk factors. We conducted a multi-center retrospective study on adult NJSA patients at three teaching hospitals in South Korea from 2005 to 2017. Among 101 patients diagnosed with S. aureus NJSA, 39 (38.6%) had MRSA strains. Compared to MSSA, patients with MRSA had a higher prevalence of nosocomial infections (17.9% vs. 1.6%; p = 0.005) and received inappropriate antibiotics within 48 h more frequently (74.4% vs. 0%; p < 0.001). In total, twenty patients (19.8%) experienced treatment failure, which encompassed five patients (5.0%) who passed away, nine (8.9%) requiring repeated surgical drainage after 30 days of antibiotic therapy, and seven (6.9%) with relapse. The MRSA group showed a higher rate of overall treatment failure (33.3% vs. 11.3%; p = 0.007) with a notably increased frequency of requiring repeated surgical interventions after 30 days of antibiotic therapy (17.9% vs. 3.2%, p = 0.026), in contrast to the MSSA group. Independent risk factors for treatment failure included Charlson comorbidity score, elevated CRP levels, and methicillin resistance. Methicillin resistance is an independent risk factor for treatment failure, emphasizing the need for vigilant monitoring and targeted interventions in MRSA-related NJSA cases.

Evaluation of the impact of rifampicin on the plasma concentration of linezolid in tuberculosis co-infected patients

Linezolid combined with rifampicin has shown excellent clinical outcomes against infection by multi-resistant Gram-positive bacteria. However, several studies have indicated that rifampicin reduces the plasma concentration of linezolid in patients with severe infection. Linezolid has been recommended for the treatment of patients with multidrug-resistant or extensively drug-resistant tuberculosis. However, studies on the interaction between linezolid and rifampicin in patients suffering from tuberculosis with infection are lacking. We evaluated the interaction between linezolid and rifampicin based on therapeutic drug monitoring (TDM). A retrospective analysis was undertaken for patients with tuberculosis and infection who were treated with linezolid and undergoing TDM. Patients were divided into the linezolid group and linezolid + rifampicin group. Data on demographic characteristics, disease, duration of linezolid therapy, and the plasma concentration of linezolid were used for statistical analyses. Eighty-eight patients with tuberculosis and infection were assessed. Values for the peak (Cmax) and trough (Cmin) concentrations of linezolid in plasma were available for 42 and 46 cases, respectively. Patients in the linezolid group had a significantly higher Cmax [15.76 (8.07-26.06) vs. 13.18 (7.48-23.64) mg/L, p = 0.048] and Cmin [8.38 (3.06-16.53) vs. 4.27 (0.45-10.47), p = 0.005] than those in the linezolid + rifampicin group. The plasma concentration of linezolid increased obviously in two patients after rifampicin discontinuation. However, the total efficiency and prevalence of hematologic adverse reactions were not significantly different in the linezolid group and linezolid + rifampin group. The plasma concentration of linezolid decreased upon combination with rifampicin, suggesting that TDM may aid avoidance of subtherapeutic levels of linezolid upon co-treatment with rifampicin.

A descriptive study of vancomycin use at Red Cross War Memorial Children's Hospital, Cape Town

Background

Antimicrobial stewardship principles guide the clinical use of antimicrobials, including vancomycin, but paediatric vancomycin prescribing practices have not been evaluated in South Africa.

Objectives

To document the use, prescribing practices and monitoring of intravenous vancomycin and the spectrum of bacteria isolated on microbiological culture in children treated with intravenous vancomycin during a 12-month period at Red Cross War Memorial Children's Hospital (RCWMCH).

Method

A retrospective audit of intravenous vancomycin use in children admitted to RCWMCH during 2019 was performed.

Results

All 158 vancomycin prescription episodes for 143 children were included. Overall usage of intravenous vancomycin was 63 days of therapy per 1000 patient days (interquartile range [IQR]: 38-72). The median starting dose was 15 mg/kg per dose (IQR: 14-15) and median daily dose was 45 mg/kg per day (IQR: 43-60). Vancomycin was prescribed as empiric (127/158, 80%) and directed (31/158, 20%) treatment. The median duration of treatment for the directed group (7 days) was longer than the empiric group (4 days) (p = 0.001). Vancomycin serum trough concentrations were performed in 65/98 (66%) episodes where vancomycin treatment exceeded 3 days, with only 16/65 (25%) of these samples obtained before the fourth dose. Prolonged antibiotic treatment of 14 days or more was not associated with Gram-positive bacteria on culture (odds ratio [OR]: 1.02, 95% confidence interval [CI]: 0.17-4.2).

Conclusion

Dosing errors, prolonged empiric treatment and inappropriate vancomycin monitoring were problems associated with vancomycin prescriptions.

Contribution

The study identified multiple opportunities for improved vancomycin prescribing and monitoring. Further research and implementation of improved prescribing practices could contribute to the preservation of vancomycin as an effective antibiotic.

Therapeutic Options for Adult Patients With Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Narrative Review

OBJECTIVE

To compare the efficacy of antimicrobial therapies used in the management of persistent methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia.

DATA SOURCES

A literature search using the PubMed database (inception to December 2022) was conducted using the search terms "Staphylococcus aureus bacteremia," "methicillin-susceptible Staphylococcus aureus bacteremia," "persistent methicillin-susceptible Staphylococcus aureus bacteremia," and "refractory methicillin-susceptible Staphylococcus aureus bacteremia ." In addition, therapeutic agents which could be used as treatment for MSSA including "nafcillin," "oxacillin," "cefazolin," "ceftaroline," "gentamicin," "rifampin," and "daptomycin" were also combined with the aforementioned search terms to capture data using these agents.

STUDY SELECTION/DATA EXTRACTION

Clinical data were limited to those published in the English language. Articles and abstracts were considered for inclusion in addition to ongoing trials identified through ClinicalTrials.gov.

DATA SYNTHESIS

A total of 78 articles were reviewed including 17 in vitro or animal model studies and 39 studies including patient data. The remaining 22 articles included guidelines, review articles, and editorials. Recent data evaluating use of dual β-lactam regimens for persistent MSSA bacteremia were limited to 8 case reports or case series.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

At present, there is little guidance on how to best manage patients with persistent MSSA bacteremia. This narrative review collates the available data to assist clinicians in selecting the best possible antimicrobial regimen when facing this clinical conundrum.

CONCLUSIONS

Modification of antimicrobial therapy, in conjunction with source control and infectious diseases consultation, may all be necessary to sterilize blood cultures in patients with persistent MSSA bacteremia.

Treatment optimization by monitoring vancomycin concentration in the serum and cerebrospinal fluid in a child with cystoperitoneal shunt-related infection caused by methicillin-resistant Staphylococcus aureus: a case report and literature review

BACKGROUND

Cerebral ventricular shunt infections caused by methicillin-resistant Staphylococcus aureus (MRSA), especially strains with elevated minimum inhibitory concentration (MIC) values, have a poor prognosis. Monitoring serum vancomycin (VCM) levels with therapeutic drug monitoring and maintaining high VCM concentrations in the cerebrospinal fluid (CSF) are critical to treatment success. However, there have been a few reports about the CSF penetration and the pharmacokinetics of VCM in children.

CASE PRESENTATION

Here, we report the case of a pediatric patient with cysto-peritoneal shunt-related meningitis caused by MRSA with an MIC of 2 μg/mL. The adequate VCM concentration was maintained by monitoring the VCM concentration in the CSF via the external ventricular drain, and frequent blood taking was avoided. VCM showed a good CSF penetration in our patient, and she was discharged without complications.

DISCUSSION

Therapeutic drug monitoring of VCM concentration in the CSF may result in successful treatment even if MRSA shows a higher MIC. Therapeutic drug monitoring of VCM concentration in the CSF may also reduce the side effects.

Oritavancin vs Standard of Care for Treatment of Nonendovascular Gram-Positive Bloodstream Infections

Background

Data is limited comparing oritavancin (ORT) to the standard-of-care (SOC) for the treatment gram-positive blood stream infections (BSI).

Methods

This was a retrospective study of all patients in the Veteran's Affairs Health Care System treated with at least 1 dose of oritavancin or at least 5 days of vancomycin, daptomycin, ceftaroline, ampicillin, ampicillin-sulbactam, nafcillin, oxacillin, or cefazolin for a documented gram-positive BSI from 1 January 2015 to 30 June 2021. Patients with polymicrobial blood cultures or positive cultures from other sites were included if the organisms were sensitive to the incident antimicrobial; no concomitant antimicrobials could be used once the incident agent was started. Individuals were also excluded if they were diagnosed with endocarditis, had a neutrophil count 96-hours of treatment before the incident antimicrobial was started.The primary composite outcome was clinical failure, defined as all-cause mortality within 30-days from the end of therapy, or blood cultures positive for the incident organisms ≥72 hours after administration of the first dose and ≤30 days after the administration of the final dose of the study antimicrobial, or any drug or line-related readmissions within 30-days of hospital discharge.

Results

Two hundred-forty patients were identified for screening with 96 meeting criteria (27 in ORT and 69 in SOC groups). Baseline characteristics were generally balanced between groups except more patients in the ORT group received >96-hours of treatment before the incident antimicrobial was started (70.3% (19/27) vs 13.04% 9/69); P < .001). The pathogen most prevalent was methicillin susceptible Staphylococcus aureus (MSSA) (ORT 33.3% (9/27) vs SOC 46.4% (32/69)). Clinical failure occurred in 7.4% (2/27) in the ORT group and 17.4% (12/69) in SOC (P = .34). No components of the primary outcome were significantly different between groups, but AKI did occur more commonly in the SOC group (27.5% (19/69) vs 3.7% (1/27); P = .01).

Conclusions

ORT appears to be a safe and effective option when directly compared to the SOC for non-endocarditis BSIs.