Detection of Methicillin-Resistant Staphylococcus aureus Infections Using Molecular Methods

Electrochemical pH Sensor Incorporated Wearables for State-of-the-Art Wound Care

Nonhealing chronic wounds pose severe physiological and psychological distress to patients, making them a significant concern for global public health. Effective wound management strategies assisted by smart wearable pH monitoring have the potential to substantially alleviate both social and economic burdens. The pH of the wound exudate serves as a valuable indicator for predicting infections and assessing the healing status of wounds. This review comprehensively summarizes fundamental aspects related to wound pH, with a particular emphasis on the relationships between pH and healing status, infections, and other biochemical parameters that are crucial for wound health. It systematically discusses advancements in electrochemical pH sensors specifically designed for wearable devices, emphasizing their core performance in the care of chronic wounds. Additionally, the review outlines the challenges faced by this field and suggests future directions for research and development.

Staphylococcus aureus bacteraemia for the general physician: A narrative review of a metastatic infection with malignant complications

Staphylococcus aureus bacteraemia (SAB) is a multi-system disease associated with a 20-25% mortality in the UK setting. Many patients with SAB are admitted acutely unwell and are treated by the general physician. This review summarises the key management steps that a general physician needs to be aware of when treating patients with SAB. Successful management relies on appropriate empirical and definitive antimicrobial therapy, effective source control, accurate risk stratification and timely identification of metastatic foci of infection, as well as exclusion of infective endocarditis, which can be present in up to 10% of patients with SAB.

Antibiotic Use in the Surgical Intensive Care Unit

Judicious use of antibiotics in the critically ill starts with the evaluation for suspected infection, including close consideration of the patient's history. If infection is present or strongly suspected, empiric antibiotics should be promptly initiated and selected based on the source of infection, patient factors, and local resistance patterns. If the surgeon decides source control is indicated, they must determine the optimal approach and timing. As soon as culture and sensitivity data are available, de-escalation to narrower spectrum agents is essential to decrease the risks of antibiotic toxicity and resistance. Importantly, surgeons should participate in antibiotic stewardship in their patients.

Rapid and sensitive detection of methicillin-resistant Staphylococcus aureus through the RPA-PfAgo system

Introduction

Both the incidence and mortality rates associated with methicillin-resistant Staphylococcus aureus (MRSA) have progressively increased worldwide. A nucleic acid testing system was developed in response, enabling swift and precise detection of Staphylococcus aureus (S. aureus) and its MRSA infection status. This facilitates improved prevention and control of MRSA infections.

Methods

In this work, we introduce a novel assay platform developed by integrating Pyrococcus furiosus Argonaute (PfAgo) with recombinase polymerase amplification (RPA), which was designed for the simultaneous detection of the nuc and mecA genes in MRSA.

Results

This innovative approach enables visual MRSA detection within 55 mins, boasting a detection limit of 102 copies/μL. Characterized by its high specificity, the platform accurately identifies MRSA infections without cross-reactivity to other clinical pathogens, highlighting its unique capability for S. aureus infection diagnostics amidst bacterial diversity. Validation of this method was performed on 40 clinical isolates, demonstrating a 95.0% accuracy rate in comparison to the established Vitek2-COMPACT system.

Discussion

The RPA-PfAgo platform has emerged as a superior diagnostic tool, offering enhanced sensitivity, specificity, and identification efficacy for MRSA detection. Our findings underscore the potential of this platform to significantly improve the diagnosis and management of MRSA infection.

Nitrate Reductase Assay for Rapid Determination of Methicillin-Resistant Staphylococcus aureus Clinical Isolates

OBJECTIVE

To evaluate the performance of nitrate reductase assay (NRA), a rapid, colorimetric method for the determination of methicillin resistance in Staphylococcus aureus isolates obtained from the culture collection of the Akdeniz University Hospital Central Laboratory, Antalya, Türkiye.

MATERIALS AND METHODS

Identification for all 290 S aureus isolates at the species level was performed via matrix-assisted laser desorption/ionization-time of flight. Isolates were tested with NRA for methicillin resistance. The cefoxitin broth microdilution (BMD) method recommended by the Clinical and Laboratory Standards Institute was used as the reference method in the study. S aureus ATCC 29213 and S aureus ATCC 43300 strains were used for quality control.

RESULTS

According to Food and Drug Administration criteria, the category agreement between NRA and BMD was found to be 100%. The essential agreement between both methods was determined to be 96.20%. There is no minor, major, or extremely major discrepancy between both methods.

CONCLUSION

The results show that NRA is a rapid, practical, and reliable colorimetric method for detecting MRSA.

The diagnostic accuracy of the GeneXpert ESBL-ampC prototype assay for rapid PCR-based detection of extended-spectrum beta-lactamase genes directly from urine

IMPORTANCE

Early identification of complicated urinary tract infections caused by ESBL-producing Enterobacterales has the potential to limit the use of carbapenems to those patients without alternative antibiotic options and avoid the empirical use of carbapenems in patients without ESBL-producing bacteria. The purpose for such a test will differ by setting and ESBL prevalence rates. Countries with low ESBL rates and cephalosporins as empiric treatment (e.g., The Netherlands) will need a rule-in test to decide to use carbapenems, while countries with high ESBL rates and empiric carbapenem treatment will need a rule-out test for ESBLs to de-escalate therapy early. Anyway, such as a test would-at least theoretically-improve patient care and reduce selective pressure for the emergence of carbapenem resistance.

Antibiotic stewardship in the ICU: time to shift into overdrive

Antibiotic resistance is a major health problem and will be probably one of the leading causes of deaths in the coming years. One of the most effective ways to fight against resistance is to decrease antibiotic consumption. Intensive care units (ICUs) are places where antibiotics are widely prescribed, and where multidrug-resistant pathogens are frequently encountered. However, ICU physicians may have opportunities to decrease antibiotics consumption and to apply antimicrobial stewardship programs. The main measures that may be implemented include refraining from immediate prescription of antibiotics when infection is suspected (except in patients with shock, where immediate administration of antibiotics is essential); limiting empiric broad-spectrum antibiotics (including anti-MRSA antibiotics) in patients without risk factors for multidrug-resistant pathogens; switching to monotherapy instead of combination therapy and narrowing spectrum when culture and susceptibility tests results are available; limiting the use of carbapenems to extended-spectrum beta-lactamase-producing Enterobacteriaceae, and new beta-lactams to difficult-to-treat pathogen (when these news beta-lactams are the only available option); and shortening the duration of antimicrobial treatment, the use of procalcitonin being one tool to attain this goal. Antimicrobial stewardship programs should combine these measures rather than applying a single one. ICUs and ICU physicians should be at the frontline for developing antimicrobial stewardship programs.

A review of horses as a source of spreading livestock-associated methicillin-resistant Staphylococcus aureus to human health

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was first discovered in horses in 1989. Since then, LA-MRSA has begun to be considered an important strain of pathogenic bacteria in horses, which can cause LA-MRSA infection and colonization in humans with public health impacts. The anterior nares are the primary site of LA-MRSA colonization in horses, although LA-MRSA colonization may also occur in the gastrointestinal tract in horses. LA-MRSA-infected horses typically exhibit clinical infection or may not exhibit clinical infection. There are two potential risks associated with LA-MRSA colonization in horses: The possibility of disease development in horses infected with LA-MRSA and the possibility of LA-MRSA transfer to humans and other horses. The diagnosis of LA-MRSA in horses can be made by conducting in vitro sensitivity testing for oxacillin and cefoxitin, and then followed by a molecular test using polymerase chain reaction. LA-MRSA transmission in animal hospitals and on farms is most likely due to contact with horses infected or colonized by LA-MRSA. The history of prior antibiotic administration, history of prior LA-MRSA colonization, and length of equine hospitalization were described as risk factors in cases of infection and colonization of LA-MRSA in horses. Nebulized antibiotics may be a viable alternative to use in horses, but nebulized antibiotics are only used in horses that are persistently colonized with LA-MRSA. Controlling the spread of LA-MRSA in horses can be done by regularly washing horses, eradicating vectors in horse stalls such as rats, and maintaining the cleanliness of the stable and animal hospital environment. Meanwhile, cleaning hands, using gloves, and donning protective clothes are ways that humans can prevent the transmission of LA-MRSA when handling horses. This review will explain the definition of LA-MRSA in general, LA-MRSA in horses, the epi­demiology of LA-MRSA in horses, the diagnosis of LA-MRSA in horses, the transmission of LA-MRSA in horses, risk factors for spreading LA-MRSA in horses, public health impact, treatment of LA-MRSA infection in horses, and control of the spread of LA-MRSA in horses.