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The simplest point-of-care assays are usually paper and plastic devices that detect proteins or nucleic acids at low cost and minimal user steps, albeit with poor limits of detection. Digital assays improve limits of detection and analyte quantification by splitting a sample across many wells (or droplets), preventing diffusion, and performing analyte amplification and detection in multiple small wells. However, truly digital nucleic acid amplification tests (NAATs) require costly consumable cartridges that are precisely manufactured, aligned, and operated to enable low detection limits. In this study, we demonstrate how to implement near-digital NAATs in low-cost porous media while approaching the low limits of detection of digital assays. The near-digital NAAT was enabled by a paper membrane containing lyophilized amplification reagents that automatically, passively meters and distributes a sample over a wide area. Performing a NAAT in the paper membrane while allowing diffusion captures many of the benefits of digital NAATs if the pad is imaged at a high spatial resolution during amplification. We show that the near-digital NAAT is compatible with a low-cost paper and plastic disposable cartridge coupled to a 2-layer rigid printed circuit board heater (the MD NAAT platform). We also demonstrate compatibility with biplexing and imaging with mobile phones with different camera sensors. We show that the near-digital NAAT increased signal-to-noise ratios by ~ 10×, improved limits of detection from above 10 3 copies of methicillin-resistant Staphylococcus aureus genomic DNA to between 100 and 316 copies in a biplexed reaction containing 10 5 copies of co-amplifying internal amplification control DNA, and reduced time-to-result from 45 min of amplification to 15-20 min for the positive samples., (© 2022. The Author(s).)

A rapid, highly sensitive, and quantitative colorimetric paper-based analytical device (PAD) based on silver nanoplates (AgNPls) and loop-mediated isothermal amplification (LAMP) is presented. It is shown that cauliflower-like concatemer LAMP products can mediate crystal etching of AgNPls, with a threefold signal enhancement versus linear dsDNA. Methicillin-resistant Staphylococcus aureus (MRSA), an antimicrobial resistant bacterium that poses a formidable risk with persistently high mortality, is used as a model pathogen. Due to the excellent color contrast provided by AgNPls, the PAD allows qualitative analysis by the naked eye and quantitative analysis using a smartphone camera, with detection limits down to a single copy in just 30 min, and a linear response from 1 to 10 4 copies (R 2 = 0.994). The entire assay runs in situ on the paper surface, which drastically simplifies operation of the device. This is the first demonstration of single copy detection using a colorimetric readout, and the developed PAD shows great promise for translation into an ultrasensitive gene-based point-of-care test for any infectious disease target, via modification of the LAMP primer set., (© 2020 Wiley-VCH GmbH.)

Loop-mediated isothermal amplification (LAMP) has been widely used to detect many infectious diseases. However, minor inconveniences during the steps of adding reaction ingredients and lack of simple color results hinder point-of-care detection. We therefore invented a fluorometric paper-based LAMP by incorporating LAMP reagents, including a biotinylated primer, onto a cellulose membrane paper, with a simple DNA fluorescent dye incubation that demonstrated rapid and accurate results parallel to quantitative polymerase chain reaction (qPCR) methods. This technology allows for instant paper strip detection of methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory and clinical samples. MRSA represents a major public health problem as it can cause infections in different parts of the human body and yet is resistant to commonly used antibiotics. In this study, we optimized LAMP reaction ingredients and incubation conditions following a central composite design (CCD) that yielded the shortest reaction time with high sensitivity. These CCD components and conditions were used to construct the paper-based LAMP reaction by immobilizing the biotinylated primer and the rest of the LAMP reagents to produce the ready-to-use MRSA diagnostic device. Our paper-based LAMP device could detect as low as 10 ag (equivalent to 1 copy) of the MRSA gene mecA within 36-43 min, was evaluated using both laboratory (individual cultures of MRSA and non-MRSA bacteria) and clinical blood samples to be 100% specific and sensitive compared to qPCR results, and had 35 day stability under 25 °C storage. Furthermore, the color readout allows for quantitation of MRSA copies. Hence, this device is applicable for point-of-care MRSA detection.

Animal derived milk which is an important part of human diet due to its high nutritional value not only supports humans but also presents a growth environment for pathogenic bacteria. Milk may become contaminated with bacteria through udder infections or through contact within the dairy farm environment. Infections are treated with antibiotics, with β-lactams most commonly used in veterinary medicine. However, their frequent use leads to the emergence of β-lactam resistant bacterial strains, which causes difficulties in the treatment of infections in both humans and animals. Detection of pathogens as well as their antibiotic sensitivity is a pre-requisite for successful treatment and this is generally achieved with laboratory-based techniques such as growth inhibition assays, enzyme-linked immunosorbent assays (ELISA) or polymerase chain reactions (PCRs), which are unavailable in resource-limited settings. Here, we investigated paper-based analytical devices (μPADs) for the presumptive detection of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and their antibiotic resistant bacterial strains in milk samples. The μPADs were fabricated on filter paper using wax printing, and then impregnated with chromogenic substrates, which reacted with bacterial enzymes to form coloured products. Limits of detection of S. aureus and E. coli and their antibiotic resistant strains in milk samples were found to be 106 cfu mL-1. Enrichment of milk samples in a selective medium for 12 h enabled detection as low as 10 cfu mL-1. The paper devices tested on a set of 640 milk samples collected from dairy animals in Pakistan demonstrated more than 90% sensitivity and 100% selectivity compared to PCR, showing promise to provide inexpensive and portable diagnostic solutions for the detection of pathogenic bacteria in resource-limited settings.

The study of Masclaux et al., in this issue of the Annals of Occupational Hygiene, describes measurement of Staphylococcus bacteria in pig farms using classical viable measurement techniques and molecular techniques. Molecular techniques find application in hygiene field studies more often and create new opportunities. Common dust sampling approaches can be used in combination with molecular techniques and high numbers of samples can be processed creating opportunities for hygiene control and for exposure assessment in the context of epidemiological surveys. Hygienists should be aware of the advantages and disadvantages of the use of these techniques. Aspects of microbial sampling are briefly reviewed.

The scope of this reflection paper was to review the latest research on the risk of MRSA infection and colonization in animals. Attention focused on occurrence, risk factors for colonization and infection, and human contact hazard for livestock, horses, and companion animals. Whereas the clonal relationship between MRSA strains of CC398 is straightforward in livestock this is less obvious in horses. Small companion animals typically share MRSA strains that seem to exchange with a human reservoir. Management and therapeutic options have been suggested for livestock, horses, companion animals, as well as instructions on safety measures for persons in contact with animals. Conclusions were drawn with emphasis on future research activities, especially to confirm the apparent evolution of the organism and to demonstrate efficiency of control strategies.

Chemical biocides are used for the prevention and control of infection in health care, targeted home hygiene or controlling microbial contamination for various industrial processes including but not limited to food, water and petroleum. However, their use has substantially increased since the implementation of programmes to control outbreaks of methicillin-resistant Staphylococcus aureus, Clostridioides difficile and severe acute respiratory syndrome coronavirus 2. Biocides interact with multiple targets on the bacterial cells. The number of targets affected and the severity of damage will result in an irreversible bactericidal effect or a reversible bacteriostatic one. Most biocides primarily target the cytoplasmic membrane and enzymes, although the specific bactericidal mechanisms vary among different biocide chemistries. Inappropriate usage or low concentrations of a biocide may act as a stressor while not killing bacterial pathogens, potentially leading to antimicrobial resistance. Biocides can also promote the transfer of antimicrobial resistance genes. In this Review, we explore our current understanding of the mechanisms of action of biocides, the bacterial resistance mechanisms encompassing both intrinsic and acquired resistance and the influence of bacterial biofilms on resistance. We also consider the impact of bacteria that survive biocide exposure in environmental and clinical contexts., (© 2023. Springer Nature Limited.)

Iron coating was introduced as one of the novel techniques to improve physicochemical and biological properties of silver nanoparticles (AgNPs). In the current experiment, impact of iron coating on the antimicrobial potency of AgNPs was investigated against methicillin-resistance Staphylococcus aureus (MRSA). To obtain more accurate data about the antimicrobial potency of examined nanostructures, the experiment was done on the 10 isolates of MRSA which were isolated from skin lesions. AgNPs and iron-coated AgNPs (Fe@AgNPs) were fabricated based on a green one-pot reaction procedure. Minimal inhibitory concentration (MIC) of Fe@AgNPs was not significantly different with MIC of AgNPs against eight out of 10 examined MRSA isolates. Also, by iron coating a reduction in the minimal inhibitory concentration (MIC) of AgNPs was observed against two MRSA isolates. The average MIC of AgNPs against 10 MRSA isolates was calculated to be 2.16 ± 0.382 mg/mL and this value was reduced to 1.70 ± 0.638 mg/mL for Fe@AgNPs. However, this difference was not considered significant statistically (P-value > 0.05). From productivity point of view, it was found that iron coating would improve the productivity of the synthesis reaction more than fivefold. Productivity of AgNPs was calculated to be 1.02 ± 0.07 g/L, meanwhile this value was 5.25 ± 0.05 g/L for Fe@AgNPs. Iron coating may provide another economic benefit to reduce final price of AgNPs. It is obvious that the price of a particular nanostructure made of silver and iron is significantly lower than that of pure silver. These findings can be considered for the fabrication of economic and potent antimicrobial nanoparticles., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aim: Paper is used for various purposes in hospitals. Generally, there are two different types of paper, which are commonly used in our facility: wood-free paper, and paper containing wood. We compared the recoverable proportion of methicillin-resistant (MRSA; ATCC 43300) from the surface of such papers. Method: The papers were divided into two groups: Group 1: wood-free paper; Group 2: paper containing wood. The papers were contaminated in a standardized procedure with 0.1 mL of a 5×10 CFU MRSA/mL stock solution. Results: The recoverable proportion of MRSA was higher in the wood-containing papers than in the papers without wood (P=0.043). Conclusion: This study indicates that if paper is purchased for healthcare facilities it should not contain wood, but rather wood-free paper types should be considered.

Objective: To assess the impact of active surveillance and decolonization strategies on methicillin-resistant Staphylococcus aureus (MRSA) infection rates in a NICU., Study Design: MRSA infection rates were compared before (2014-2016) and during (2017-2022) an active surveillance program. Eligible infants were decolonized with chlorohexidine gluconate (CHG) bathing and/or topical mupirocin. Successful decolonization and rates of recolonization were assessed., Results: Fifty-two (0.57%) of 9 100 hospitalized infants had invasive MRSA infections from 2014 to 2022; infection rates declined non-significantly. During the 6-year surveillance program, the risk of infection was 16.9-times [CI 95 8.4, 34.1] higher in colonized infants than uncolonized infants. Those colonized with mupirocin-susceptible MRSA were more likely successfully decolonized (aOR 9.7 [CI 95 4.2, 22.5]). Of 57 infants successfully decolonized who remained hospitalized, 34 (60%) became recolonized., Conclusions: MRSA infection rates did not significantly decline in association with an active surveillance and decolonization program. Alternatives to mupirocin and CHG are needed to facilitate decolonization., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Staphylococcus aureus can cause localized infections such as abscesses and pneumonia, as well as systemic infections such as bacteremia and sepsis. Especially, methicillin-resistant S. aureus often presents multidrug resistance, which becomes a major clinical challenge. One of the most common reasons for methicillin-resistant S. aureus antibiotic resistance is the presence of biofilms. Natural antimicrobial peptides derived from different species have shown effectiveness in combating S. aureus biofilms. In this review, we summarize the inhibitory activity of antimicrobial peptides against S. aureus planktonic cells and biofilms. We also summarize the possible inhibitory mechanisms, involving cell adhesion inhibition, membrane fracture, biofilm disruption and DNA disruption. We believe this can provide the basis for further research against S. aureus biofilm-associated infections.

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., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: The area under the curve (AUC) to minimum inhibitory concentration (MIC) ratio is proposed as a therapeutic drug-monitoring parameter for dosing vancomycin continuous infusion in methicillin-resistant Staphylococcus aureus (MRSA) infection. Individualised pharmacokinetic-pharmacodynamic (PK/PD) calculation of AUC 24 may better represent therapeutic dosing than current Therapeutic Drug Monitoring (TDM) practices, targeting a Steady State Concentration of 15-25 mg/L., Aim: To compare real world TDM practice to theoretical, individualised, PK/PD target parameters utilising Bayesian predictions to steady state concentrations (Css) for outpatients on continuous vancomycin infusions., Method: A retrospective single centre study was conducted at a tertiary hospital on adult patients, enrolled in an outpatient parenteral antimicrobial therapy (OPAT) program, receiving vancomycin infusions for MRSA infection. Retrospective Bayesian dosing was modelled to target PK/PD parameters and compared to real world data., Results: Fifteen patients were evaluated with 53% (8/15) achieved target C SS during hospitalisation, and 83% (13/15) as outpatient. Median Bayesian AUC/MIC was 613 mg.h/L with C SS 25 mg/L. Patients suffering an Acute Kidney Injury (33%) had higher AUC 0-24 /MIC values. Retrospective Bayesian modelling demonstrated on median 250 mg/24 h lower doses than that administered was required (R 2  = 0.81) which achieved AUC 24 /MIC median 444.8 (range 405-460) mg.h/L and C SS 18.8 (range 16.8-20.4) mg/L., Conclusion: Bayesian modelling could assist in obtaining more timely target parameters at lower doses for patients receiving continuous vancomycin infusion as part of an OPAT program, which may beget fewer adverse effects. Utilisation of personalised predictive modelling may optimise vancomycin prescribing, achieving earlier target concentrations as compared to empiric dosing regimens., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Multidrug-resistant (MDR) bacterial infections constitute a major public health problem worldwide. A rapid method for the detection of methicillin-resistant Staphylococcus aureus (MRSA) is critical for the timely prevention of bacterial infections and the accurate clinical use of drugs. The nuc and mecA genes are potentially indicative of MRSA infection and in this study, a multiplex molecular fluorescence multi-enzyme isothermal rapid amplification visual assay was proposed and established. The method is capable of detecting MRSA at 17 min, 40°C amplification, and is well differentiated from common clinical bacteria in specific assays, with 500 colony-forming units (CFU) mL -1 of MRSA detected under optimal conditions. This method has excellent diagnostic capabilities versus classical methods to detect clinical samples and shows potential in the identification of pathogenic microorganisms in a clinical setting., (© 2023 Wiley-VCH GmbH.)

Objective: Investigate incidence and natural history of otologic and sinonasal disease associated with 22q11.2 deletion syndrome., Study Design: Case series., Setting: Tertiary care children's hospital., Methods: Charts from consecutive children born 2000 to 2018 with a diagnosis of 22q11.2 deletion, DiGeorge, or velocardiofacial syndrome based on the International Classification of Diseases (ICD)-9 and ICD-10 codes were reviewed. Otologic and rhinologic diagnoses and surgeries and immune and microbiologic laboratory findings were collected from the medical record., Results: After the exclusion of patients with no 22q11.2 deletion (n = 101), otologic care at an outside hospital (n = 59), and loss to follow-up prior to 3 years of age (n = 22), 128 were included. Males comprised 80 (62.5%) patients, 115 (89.8%) were white, and the median age at genetic confirmation of 22q11.2 deletion was 119 days (range 0 days to 14.6 years). Recurrent acute otitis media (RAOM), chronic otitis media with effusion, chronic rhinosinusitis, and recurrent acute sinusitis were diagnosed in 54 (42.2%), 37 (28.9%), 10 (7.8%), and 8 (6.3%), respectively. Tympanostomy tubes were placed in 49 (38.3%). Adenoidectomy and sinus surgery were performed in 38 (29.7%) and 4 (3.1%), respectively. Neither immunoglobulin nor cluster of differentiation deficiency increased the odds of RAOM diagnosis, tympanostomy tube placement, or chronic/recurrent sinusitis. Methicillin-resistant Staphylococcus aureus was the most common organism in sinus cultures (4/13, 30.8%). Streptococcus pneumonia dominated otorrhea cultures (11/21, 52.4%)., Conclusion: Approximately half of children with 22q11.2 deletion may experience otologic disease that often requires surgical management. Future studies will utilize a larger cohort to examine the role of immunodeficiency in otologic and rhinologic disease in this population., (© 2023 American Academy of Otolaryngology-Head and Neck Surgery Foundation.)

Vancomycin-resistant Staphylococcus aureus (VRSA) is a zoonotic life-threatening pathogen. Vancomycin exhibits anti-bacterial activity by inhibiting peptidoglycan synthesis by binding to the D-ala-D-ala terminus of the peptidoglycan. But in VRSA, D-ala-D-ala is replaced by D-ala-D-lactate due to the presence of vanA, vanB or vanD genes. This study was intended to identify the molecular prevalence of VRSA in 768 bovine milk samples, risk factor association, antibiogram profile and bioinformatics analysis of VRSA by targeting vanB gene. Out of a total of 248 S. aureus isolates from mastitic milk samples, the phenotypic and genotypic prevalence of VRSA was estimated to be 17.74% and 10.89%, respectively. Farm-level risk factors including use of improper milking technique, lack of milker's care during milking, unhygienic conditions during milking and no dry cow therapy were found to be significantly associated (p < 0.05). Anti-microbial susceptibility testing of VRSA isolates exhibited the highest resistance to oxytetracycline, followed by oxacillin and Trimethoprim+sulfamethoxazole. The current study sequences showed more resemblance with reported sequences from Iraq (MN747834) and Egypt (MK095504, MK087830), which belong to vanB gene from S. aureus as compared to sequences from other countries, which belong to vanB gene from the genus Enterococcus. The Genetic Algorithm for Recombination Detection (GARD) found 234 potential breakpoints, translating into a search room of 123,883,305 models with up to 4 breakpoints. The phylogenetic motif profiling method discovered evolutionarily conserved residues across target genes' homologous protein sequences. These residues were discovered to be conserved in drug-resistant target proteins over the evolutionary process and may play a key role in their function. The current study revealed a molecular prevalence of VRSA in dairy animals, along with molecular analysis of vancomycin resistance in S. aureus by targeting the vanB gene using standard bioinformatics tools. The occurrence of VRSA in animals requires serious attention because this pathogen has zoonotic potential, so it can become a greater risk to consumer health., (© 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

Staphylococcus argenteus and Staphylococcus schweitzeri, previously known as divergent Staphylococcus aureus clonal lineages, have been recently established as novel, difficult-to-delimit, coagulase-positive species within the S. aureus complex. Methicillin-resistant strains of S. argenteus are known from Australia and the UK. Knowledge of their epidemiology, medical significance and transmission risk is limited and partly contradictory, hampering definitive recommendations. There is mounting evidence that the pathogenicity of S. argenteus is similar to that of 'classical' S. aureus , while as yet no S. schweitzeri infections have been reported. To provide decision support on whether and how to distinguish and report both species. PubMed, searched for S. argenteus and S. schweitzeri. This position paper reviews the main characteristics of both species and draws conclusions for microbiological diagnostics and surveillance as well as infection prevention and control measures. We propose not distinguishing within the S. aureus complex for routine reporting purposes until there is evidence that pathogenicity or clinical outcome differ markedly between the different species. Primarily for research purposes, suitably equipped laboratories are encouraged to differentiate between S. argenteus and S. schweitzeri. Caution is urged if these novel species are explicitly reported. In such cases, a specific comment should be added (i.e. 'member of the S.aureus complex') to prevent confusion with less- or non-pathogenic staphylococci. Prioritizing aspects of patient safety, methicillin-resistant isolates should be handled as recommended for methicillin-resistant Staphylococcus aureus (MRSA). In these cases, the clinician responsible should be directly contacted and informed by the diagnosing microbiological laboratory, as they would be for MRSA. Research is warranted to clarify the epidemiology, clinical impact and implications for infection control of such isolates. [ABSTRACT FROM AUTHOR]

Background: Current methods for benchmarking inpatient antimicrobial use (AU) could benefit from combining AU with antimicrobial resistance (AR) information to provide metrics benchmarked to microbiological data; this may yield more instructive and better risk-adjusted measurements than AU and AR in isolation., Methods: In this retrospective single-center study, we computed facility-wide AU/AR ratios from 2019 to 2020 for specific antimicrobial agents and corresponding AR events, and compared median monthly AU/AR ratios between March 2019 through December 2019 (pre-COVID period) and March 2020 through December 2020 (COVID period). Aggregate AU was expressed as a ratio to aggregate AR events for antimicrobials that typically have activity against the AR organism and are frequently used to treat the AR organism in clinical practice. We also computed AU/AR ratios in our surgical intensive care unit in the pre-COVID period., Results: High-median facility-wide monthly AU/AR ratios were observed for intravenous vancomycin/methicillin-resistant Staphylococcus aureus, with 130.0 in the pre-COVID period and 121.3 in the COVID period (p =.520). Decreases in facility-wide median monthly AU/AR ratios were observed between periods for meropenem/ESBL Enterobacterales (20.9 vs. 7.9, p < .001), linezolid/vancomycin-resistant Enterococcus (48.5 vs. 15.8, p =.004), and daptomycin/vancomycin-resistant Enterococcus (32.2 vs. 4.8, p = .002). Increases in facility-wide median monthly AU/AR ratios were observed between periods for ceftazidime-avibactam/carbapenem-resistant Enterobacterales (0.0 vs. 3.2, p = .020) and ceftazidime-avibactam/multidrug-resistant Pseudomonas aeruginosa (0.0 vs. 4.0, p = .017). The AU/AR ratio for intravenous vancomycin/methicillin-resistant S. aureus in the surgical intensive care unit was 191.5 in the pre-COVID period., Conclusions: AU/AR ratios may be used to supplement current AU and AR metrics. Future directions should include the development of more AU metrics benchmarked to microbiological information. AU metrics more specific to transplant infectious diseases should be developed., (© 2022 Wiley Periodicals LLC.)

Milk and milk products can harbor a multiple varieties of microorganisms. Therefore, they can be an important source of foodborne pathogens, including multidrug-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) causes a wide spectrum of infections both in animals and humans. Over the last two decades, the presence of MRSA in foods and food-producing animals, including milk and milk products, has been frequently reported worldwide, raising public health concerns. In order to monitor and prevent foodborne MRSA contamination, it is necessary to understand their sources, the pheno/genotypic characteristics of the strains, and their transmission dynamics. In this review, studies conducted worldwide were summarized in order to assess the prevalence and diversity of MRSA circulating in milk and milk products. The risk factors for the occurrence of MRSA in milk and milk products were also discussed with preventive and control measures to avoid MRSA contamination in the dairy food chain., (© 2022 Institute of Food Technologists®.)

Mature lysostaphin (mLst) is a glycineglycine endopeptidase, capable of specifically cleaving penta-glycine crosslinker in the peptidoglycan of Staphylococcus aureus cell wall. It is a very effective therapeutic enzyme to kill the multidrug-resistant S. aureus often encountered in hospital acquired infections. Fusing cellulose binding domain (CBD) to mLst significantly reduced the insoluble expression of mLst in E. coli. Employing mLst-cleavable peptides as fusion linkers leaded to an effective self-cleavage expression that CBD and mLst could be completely cleaved off from the fusions during the expression process. The presence of residue linker fragment at N-terminus of the cleaved-off mLst strongly inhibited the cell lytic activity of the recovered recombinant mLst, and only ~ 50% of the wild-type mLst activity could be retained. Intact CBD-Lst fusions were obtained when uncleavable peptide linkers were employed. With CBD at N-terminus of mLst, the intact fusion completely lost its cell lytic activity but the dipeptidase activity still remained. In contrast, approximately 10% cell lytic activity of mLst still could be maintained for the fusion with CBD at C-terminus of mLst. KEY POINTS: • CBD fusion enhanced soluble expression of recombinant lysostaphin. • In vivo self-cleavage of fusion linkers by the expressed lysostaphin fusions. • Self-cleaved lysostaphin fusions retain most of dipeptidase but lose 50% cell lytic activity., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The epidemiology and toxigenicity of MRSA in the fishery environment are poorly understood. In this study, methicillin-resistant Staphylococcus aureus (MRSA) (n = 1) and methicillin-susceptible S. aureus (MSSA) (n = 2) from retail fish were subjected to comprehensive genome analysis. Here, we report the occurrence of ST672-MRSA-IV/t1309 and ST5-MSSA/t105 for the first time from India in the fishery environment. The resistome of the isolates was in concordance with their phenotypic resistance pattern. Phenotypically, the resistance profile of MSSA isolates (n = 2) was AMP-CLI-ERY-NOR-PEN. For MRSA (n = 1), it was AMP-CFZ-CLI-ERY-NOR-OXA-PEN. The antibiotic efflux genes and mutations in the antibiotic target accounted for fluoroquinolone resistance whereas methicillin resistance was conferred through possession of a mecA gene. Similarly, all three isolates carried a similar array of virulence factors. The conjugative plasmid inc18 and rep family 10 plasmids were found in two of the three isolates. This study documents the MRSA carrying SCCmec IVa elements which are the markers of community-associated MRSA (CA-MRSA). Through the possession of SCCmec IV elements, which are smaller than other types of SCCmec, MRSA can contribute to the rapid dissemination of antimicrobial resistance and virulence factors. In short, our findings highlighted that the presence of ST672-MRSA in fishery environments may pose a risk to human health., (© 2021 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Background: Teicoplanin is a glycopeptide antibiotic used for the treatment of methicillin-resistant Staphylococcus aureus infections. To ensure successful target attainment, therapeutic drug monitoring-informed dosage adjustment is recommended. However, it relies on the experience of the clinician and the frequency of drug measurements. This study aimed to design a new optimal dosing regimen of teicoplanin with a maintenance dosing strategy for neonates and children based on their physiological characteristics., Methods: Data from teicoplanin-treated patients (n = 214) were collected from electronic medical records. Covariate analyses were performed using population pharmacokinetic (PK) modeling with 399 serum teicoplanin concentrations from 48 neonates and 166 children. Multiple PK simulations were conducted to explore optimal dosing regimens that would allow control of the trough concentration to the target of 15-30 mg/L quicker than the current standard regimen., Results: Allometrically scaled body weight, postmenstrual age (PMA), renal function, and serum albumin were implemented as substantial covariates for teicoplanin clearance in a two-compartment PK model. Covariate analyses and comprehensive simulation assessments recommended the following modifications to the current regimen: (1) decreased dose for premature babies (PMA ≤28 weeks), (2) decreased dose for children with renal dysfunction, and (3) increased dose for children (0.5-11 years) with an estimated glomerular filtration rate of ≥90 mL/min/1.73 m2., Conclusions: This study leverages real-world clinical information and proposes new optimal dosing regimens for teicoplanin in neonates and children through PK modeling and simulation analyses, taking into account the age, including PMA, and renal function of patients., Competing Interests: Supported by JSPS KAKENHI Grant Number JP18K14951. T. Yamada was supported by a scholarship grant from the Japan Research Foundation for Clinical Pharmacology. The remaining authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Describe co-occurrence or clustering of microbial taxa in fracture-related infections to inform further exploration of infection-related interactions among them., Design: Retrospective review., Setting: Level 1 trauma center., Patients/participants: Four hundred twenty-three patients requiring surgical intervention for deep surgical site infection between January 2006 and December 2015., Intervention: None., Main Outcome Measurement: Connection between microbial taxa., Results: Methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, and coagulase-negative Staphylococcus represented the majority of monomicrobial observations (71%). Gram-negative rods, gram-positive rods, and anaerobes presented more frequently in polymicrobial infections. Enterobacter, vancomycin-sensitive Enterococcus, and Pseudomonas are present in polymicrobial infections with the highest frequencies and represent the top 3 most important nodes within the microorganism framework, with the highest network centrality scores., Conclusions: The present study indicates that there are common microbial taxa (Enterobacter, Enterococcus, and Pseudomonas) that tend to co-occur with other microbes greater than 75% of the time. These commonly co-occurring microbes have demonstrated interactive relationships in other disease pathologies, suggesting that there may be similar important interactions in fracture-related infections. It is possible that these microbial communities play a role in the persistently high failure rate associated with management of infection after trauma. Future studies are needed to study the intermicrobial interactions that explain the frequency at which taxa co-occur. Understanding and potentially disrupting these intermicrobial relationships could inform improvements in the treatment of established infections and in the prevention of infection in high-risk patients., Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: The authors report no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Gallium and its alloys, such as eutectic gallium indium alloy (EGaIn), a form of liquid metal, have recently attracted the attention of researchers due to their low toxicity and electrical and thermal conductivity for biomedical application. However, further research is required to harness EGaIn-composites advantages and address their application as a biomedical scaffold. In this research, EGaIn-polylactic acid/polycaprolactone composites with and without a second conductive filler, MXene, were prepared and characterized. The addition of MXene, into the EGaIn-composite, can improve the composite's electrochemical properties by connecting the liquid metal droplets resulting in electrically conductive continuous pathways within the polymeric matrix. The results showed that the composite with 50% EGaIn and 4% MXene, displayed optimal electrochemical properties and enhanced mechanical and radiopacity properties. Furthermore, the composite showed good biocompatibility, examined through interactions with fibroblast cells, and antibacterial properties against methicillin-resistant Staphylococcus aureus. Therefore, the liquid metal (EGaIn) polymer composite with MXene provides a first proof-of-concept engineering scaffold strategy with low toxicity, functional electrochemical properties, and promising antimicrobial properties., (© 2021 Wiley Periodicals LLC.)

Oritavancin and dalbavancin are long-acting lipoglycopeptides with activity against susceptible gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Though similar in structure to traditional glycopeptide antibiotics like vancomycin, these antibiotics have terminal half-lives >10 days, and, as a result, there is potential for administration of vancomycin to a patient while oritavancin or dalbavancin are still appreciably present in serum. Given the structural similarities, this creates an opportunity for lab assay interference when performing therapeutic drug monitoring for vancomycin. Following higher-than-expected serum vancomycin concentrations in a patient who received both oritavancin and vancomycin within a short time frame, we evaluated the potential for lipoglycopeptide interference with clinical vancomycin assays. Five platforms covering 3 immunoassay technologies were used to quantify vancomycin concentrations in serum spiked with oritavancin or dalbavancin. Oritavancin generated spurious vancomycin concentrations (20%-84% increase) in both enzyme-multiplied immunoassay technique and a particle-enhanced turbidimetric inhibition immunoassay. However, the improper detection of oritavancin was not consistent across all particle-enhanced turbidimetric inhibition immunoassay platforms. Dalbavancin interference was not detected on any of the platforms tested. The interference from oritavancin may result in falsely elevated vancomycin concentrations and, subsequently, inappropriately adjusted vancomycin doses., (© 2021, The American College of Clinical Pharmacology.)

Aim: This study aimed to identify genotype enterotoxigenic antimicrobial-resistant Staphylococcus aureus species, mainly methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) among commensal rodents., Methods and Results: A total of 280 samples were collected from nasal and mouth swabs, heart blood, intestinal content and lung tissues of 56 commensal rodents trapped from North Sinai, Egypt. Antimicrobial susceptibility testing was performed to bacteriologically identified S. aureus isolates against 15 antimicrobial agents by disc diffusion method. Detection was conducted for identifying coagulase gene (coA), antimicrobial-resistant genes (mecA and vanA/B), enterotoxigenic and virulence determinant genes (hlg, seb, sed and see) among the MRSA and VRSA isolates., Results: Staphylococcus aureus species were isolated from 24 (42.86%) out of 56 rodents. Phenotypic examination revealed that all the isolates were multidrug-resistant, whereas two isolates were multiple antibiotic resistant (MAR). Out of 33 examined isolates, 33 (100%) were resistant to oxacillin and amoxicillin, 31 (93.93%) to cefoxitin and 12 (36.36%) to vancomycin. PCR assay revealed that 24 isolates revealed (100%) positivity to coA gene, 17 (70.83%) to mecA gene and 12 (50%) to vanA/B genes. Enterotoxin genes and haemolysin genes were detected among MRSA and VRSA isolates. There was a strong positive correlation between the tested antimicrobial-resistant genes and virulence genes (p > 0.05)., Conclusions: This study demonstrated the occurrence of MRSA and VRSA strains among commensal rodents in North Sinai, Egypt. The detection of enterotoxigenic and virulence genes of the isolated MRSA and VRSA strains indicated the health hazards of food contamination and zoonotic infections., Significance and Impacts of the Study: This study emphasizes the role of commensal rodents in maintaining and disseminating multidrug-resistant MRSA and VRSA strains to the environment, animals and human beings., (© 2021 Society for Applied Microbiology.)

Staphylococcus aureus-based surgical site infections have become the leading cause of failure for total joint arthroplasty operations and remain a major issue across surgical specialties. Moreover, S. aureus-based infections are becoming drastically more difficult to treat due to the development of antibiotic resistant strains and due to the bacteria's propensity to produce biofilms. The emergence of highly resistant S. aureus infections has created the need for a novel antimicrobial treatment. Functionalized nanoparticles have recently been suggested as being a viable option to fill this void due to their strong antimicrobial and antibiofilm properties. However, said research remains a novel and developing field. The presented systematic review aimed to synthesize the best and most recent evidence available to accurately direct new research towards a viable treatment mechanism. In doing so, the authors performed a comprehensive literature search as directed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The results showed that nanoparticles-particularly those including an iron-oxide component or acidic capping agent-are a viable treatment for S. aureus infections both in vivo and in vitro, and show even greater efficacy when combined with exposure to a magnetic field and irradiation., (© 2021 The Society for Applied Microbiology.)

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Background: The aim of this research was to study the epidemiology, microbiology, prophylaxis, and antibiotic therapy of surgical site infections (SSIs), especially those caused by methicillin-resistant Staphylococcus aureus (MRSA), and identify the risk factors for these infections. In Italy SSIs occur in about 5 % of all surgical procedures. They are predominantly caused by staphylococci, and 30 % of them are diagnosed after discharge. In every surgical specialty there are specific procedures more associated with SSIs. Methods: The authors conducted a systematic review of the literature on SSIs, especially MRSA infections, and used the Delphi method to identify risk factors for these resistant infections. Results: Risk factors associated with MRSA SSIs identified by the Delphi method were: patients from long-term care facilities, recent hospitalization (within the preceding 30 days), Charlson score > 5 points, chronic obstructive pulmonary disease and thoracic surgery, antibiotic therapy with beta-lactams (especially cephalosporins and carbapenem) and/or quinolones in the preceding 30 days, age 75 years or older, current duration of hospitalization >16 days, and surgery with prothesis implantation. Protective factors were adequate antibiotic prophylaxis, laparoscopic surgery and the presence of an active, in-hospital surveillance program for the control of infections. MRSA therapy, especially with agents that enable the patient's rapid discharge from hospital is described. Conclusion: The prevention, identification and treatment of SSIs, especially those caused by MRSA, should be implemented in surgical units in order to improve clinical and economic outcomes. [ABSTRACT FROM AUTHOR]

Background: Conducting polymer based nanocomposites are known to be effective against pathogens. Herein, we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co 3 O 4 -AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii)., Results: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co 3 O 4 -AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co 3 O 4 -AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells., Conclusion: These results demonstrate that PPy-Co 3 O 4 -AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications., Key Points: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co 3 O 4 -AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co 3 O 4 -AgNPs hold promise for biomedical applications.

Background: Early attainment of target area under the curve (AUC) to minimum inhibitory concentration (MIC) ratios have been associated with clinical success, as well as lower incidence of acute kidney injury (AKI), in patients receiving vancomycin for methicillin-resistant Staphylococcus aureus (MRSA). Critically ill patients are particularly vulnerable to poor outcomes from infection and face multiple risk factors for AKI, thus early precision dosing of vancomycin is vital in this population. We hypothesized that a personalized dosing approach, using vancomycin levels obtained after the first dose to guide further dosing, would be superior to empiric dosing in terms of AUC target attainment assessed at steady state (SS)., Methods: A retrospective cohort study of 66 critically ill adult patients admitted to the medical intensive care unit without AKI and receiving vancomycin with at least two SS concentrations obtained for AUC calculation was performed. Patients were separated into cohorts based on whether they had two concentrations assessed after the first dose of vancomycin and were subsequently dosed based on personalized pharmacokinetic calculations (first-dose kinetics) or whether they were empirically dosed using population estimates. The primary outcome was AUC target attainment (400-600 mg hour/L) at SS., Results: Compared with patients receiving empiric dosing by population estimates, using first-dose kinetics to guide subsequent dosing resulted in significantly greater AUC target attainment at SS (58.6% first-dose vs 32.4% empiric; p=0.033). Patients dosed empirically yielded more variable AUC values across a wide range compared with the first-dose kinetics group (coefficient of variation 40.7% empiric vs 26.1% first-dose). There was no difference in AKI up to 48 hours after SS concentrations between the two dosing schemes., Conclusions: A dosing strategy using two vancomycin serum concentrations after the first dose and calculating personalized pharmacokinetic parameters to guide subsequent dosing is associated with greater AUC target attainment at SS compared with empiric dosing of vancomycin in critically ill adults with relatively stable renal function., (© 2020 Pharmacotherapy Publications, Inc.)