Comparison of mortality, stroke, and relapse for methicillin-resistant versus methicillin-susceptible Staphylococcus aureus infective endocarditis: a retrospective cohort study

A review on the diversity of antimicrobial peptides and genome mining strategies for their prediction

Antibiotic resistance has become one of the most serious threats to human health in recent years. In response to the increasing microbial resistance to the antibiotics currently available, it is imperative to develop new antibiotics or explore new approaches to combat antibiotic resistance. Antimicrobial peptides (AMPs) have shown considerable promise in this regard, as the microbes develop low or no resistance against them. The discovery and development of AMPs still confront numerous obstacles such as finding a target, developing assays, and identifying hits and leads, which are time-consuming processes, making it difficult to reach the market. However, with the advent of genome mining, new antibiotics could be discovered efficiently using tools such as BAGEL, antiSMASH, RODEO, etc., providing hope for better treatment of diseases in the future. Computational methods used in genome mining automatically detect and annotate biosynthetic gene clusters in genomic data, making it a useful tool in natural product discovery. This review aims to shed light on the history, diversity, and mechanisms of action of AMPs and the data on new AMPs identified by traditional as well as genome mining strategies. It further substantiates the various phases of clinical trials for some AMPs, as well as an overview of genome mining databases and tools built expressly for AMP discovery. In light of the recent advancements, it is evident that targeted genome mining stands as a beacon of hope, offering immense potential to expedite the discovery of novel antimicrobials.

Development of Aromatic-Linked Diamino Acid Antimicrobial Peptide Mimics with Low Hemolytic Toxicity and Excellent Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become one of the biggest threats to public health. To develop new antibacterial agents against MRSA, a series of diamino acid compounds with aromatic nuclei linkers were designed and synthesized. Compound 8j, which exhibited low hemolytic toxicity and the best selectivity against S. aureus (SI > 2000), showed good activity against clinical MRSA isolates (MIC = 0.5-2 μg/mL). Compound 8j was able to quickly kill bacteria without inducing bacterial resistance. A mechanistic study and transcriptome analysis revealed that compound 8j can act on phosphatidylglycerol and induce the accumulation of endogenous reactive oxygen species, which can destroy bacterial membranes. Importantly, compound 8j achieved a 2.75 log reduction of MRSA count at 10 mg/kg/d in a mouse subcutaneous infection model. These findings suggested that compound 8j had the potential to be an antibacterial agent against MRSA.

Escalation of antimicrobial resistance among MRSA part 2: focus on infections and treatment

INTRODUCTION

MRSA is associated with causing a variety of infections including skin and skin structure infections, catheter and device-related (e.g. central venous catheter, prosthetic heart valve) infections, infectious endocarditis, blood stream infections, bone, and joint infections (e.g. osteomyelitis, prosthetic joint, surgical site), central nervous system infections (e.g. meningitis, brain/spinal cord abscess, ventriculitis, hydrocephalus), respiratory tract infections (e.g. hospital-acquired pneumonia, ventilator-associated pneumonia), urinary tract infections, and gastrointestinal infections. The emergence and spread of multidrug resistant (MDR) MRSA clones has limited therapeutic options. Older agents such as vancomycin, linezolid and daptomycin and a variety of newer MRSA antimicrobials and combination therapy are available to treat serious MRSA infections.

AREAS COVERED

The authors discuss infections caused by MRSA as well as common older and newer antimicrobials and combination therapy for MRSA infections. A literature search of MRSA was performed via PubMed (up to September 2022), using the keywords: antimicrobial resistance; β-lactams; multidrug resistance, Staphylococcus aureus, vancomycin; glycolipopeptides.

EXPERT OPINION

Innovation, discovery, and development of new and novel classes of antimicrobial agents are critical to expand effective therapeutic options. The authors encourage the judicious use of antimicrobials in accordance with antimicrobial stewardship programs along with infection-control measures to minimize the spread of MRSA.

Screening neuroimaging in neurologically asymptomatic patients with infective endocarditis

BACKGROUND AND PURPOSE

Neurological complications from infective endocarditis (IE) are common and often present with minimal clinical symptoms. In this study, we examine whether screening neuroimaging in asymptomatic patients results in increased detection of neurological complications and leads to improved patient outcomes.

METHODS

Using a database of consecutive adults with IE admitted to a single health system from 2015 to 2019, we selected patients who presented without any neurological symptoms and determined whether these patients underwent screening neuroimaging. The presence of septic emboli, territorial infarcts, intracranial hemorrhage, and mycotic aneurysms was recorded. Variables with significant differences in univariable analyses (p < .1) between those with and without screening neuroimaging were entered into regression models with age and sex to determine predictors of neurological complications and favorable discharge outcomes (modified Rankin score ≤2).

RESULTS

A total of 214 patients were included in the study, of which 154 (72%) received screening neuroimaging. Septic emboli were more common in patients who underwent screening imaging (31% vs. 15%, p = 0.02). In the first multivariate analysis, screening neuroimaging was associated with septic emboli (adjusted odds ratio [aOR] = 2.44, 95% confidence interval [CI]: [1.03-5.75], p = 0.04). In the second multivariate analysis, territorial infarcts (aOR = 0.28, 95% CI: [0.11-0.73], p = .01), but not septic emboli (aOR = 0.71, 95% CI: [0.36-1.43], p = 0.34), were associated with a favorable discharge outcome.

CONCLUSIONS

Screening neuroimaging leads to the detection of more septic emboli in IE, but only territorial infarcts (in contrast to septic emboli) correlate with an unfavorable discharge outcome.