Eradication Of Methicillin-resistant Staphylococcus Aureus Research Articles

Natural approach of using nisin and its nanoform as food bio-preservatives against methicillin resistant Staphylococcus aureus and E.coli O157:H7 in yoghurt

BackgroundNatural antimicrobial agents such as nisin were used to control the growth of foodborne pathogens in dairy products. The current study aimed to examine the inhibitory effect of pure nisin and nisin nanoparticles (nisin NPs) against methicillin resistant Staphylococcus aureus (MRSA) and E.coli O157:H7 during the manufacturing and storage of yoghurt. Nisin NPs were prepared using new, natural, and safe nano-precipitation method by acetic acid. The prepared NPs were characterized using zeta-sizer and transmission electron microscopy (TEM). In addition, the cytotoxicity of nisin NPs on vero cells was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The minimum inhibitory concentrations (MICs) of nisin and its nanoparticles were determined using agar well-diffusion method. Further, fresh buffalo’s milk was inoculated with MRSA or E.coli O157:H7 (1 × 106 CFU/ml) with the addition of either nisin or nisin NPs, and then the inoculated milk was used for yoghurt making. The organoleptic properties, pH and bacterial load of the obtained yoghurt were evaluated during storage in comparison to control group.ResultsThe obtained results showed a strong antibacterial activity of nisin NPs (0.125 mg/mL) against MRSA and E.coli O157:H7 in comparison with control and pure nisin groups. Notably, complete eradication of MRSA and E.coli O157:H7 was observed in yoghurt formulated with nisin NPs after 24 h and 5th day of storage, respectively. The shelf life of yoghurt inoculated with nisin nanoparticles was extended than those manufactured without addition of such nanoparticles.ConclusionsOverall, the present study indicated that the addition of nisin NPs during processing of yoghurt could be a useful tool for food preservation against MRSA and E.coli O157:H7 in dairy industry.

MRNA-Laden Lipid-Nanoparticle-Enabled in Situ CAR-Macrophage Engineering for the Eradication of Multidrug-Resistant Bacteria in a Sepsis Mouse Model.

Sepsis, which is the most severe clinical manifestation of acute infection and has a mortality rate higher than that of cancer, represents a significant global public health burden. Persistent methicillin-resistant Staphylococcus aureus (MRSA) infection and further host immune paralysis are the leading causes of sepsis-associated death, but limited clinical interventions that target sepsis have failed to effectively restore immune homeostasis to enable complete eradication of MRSA. To restimulate anti-MRSA innate immunity, we developed CRV peptide-modified lipid nanoparticles (CRV/LNP-RNAs) for transient in situ programming of macrophages (MΦs). The CRV/LNP-RNAs enabled the delivery of MRSA-targeted chimeric antigen receptor (CAR) mRNA (SasA-CAR mRNA) and CASP11 (a key MRSA intracellular evasion target) siRNA to MΦs in situ, yielding CAR-MΦs with boosted bactericidal potency. Specifically, our results demonstrated that the engineered MΦs could efficiently phagocytose and digest MRSA intracellularly, preventing immune evasion by the "superbug" MRSA. Our findings highlight the potential of nanoparticle-enabled in vivo generation of CAR-MΦs as a therapeutic platform for multidrug-resistant (MDR) bacterial infections and should be confirmed in clinical trials.

Multiscale modeling approach to assess the impact of antibiotic treatment for COVID-19 on MRSA transmission and alternative immunotherapy treatment options

Methicillin-Resistant Staphylococcus Aureus (MRSA) infection can occur alongside or following COVID-19, which is a concern in healthcare settings. The effectiveness of antiviral treatments for COVID-19 depends on a functioning immune response, but antibiotics used for bacterial infections like MRSA can disrupt the immune response and reduce the effectiveness of antiviral treatments. The emergence of MRSA due to excessive antibiotic usage has led to the widespread use of vancomycin as an alternative treatment. Immunomodulatory antibiotics like azithromycin may also be considered. To study the dynamics of these coinfections, a multiscale model was developed. Parameter estimation and sensitivity analysis were performed, revealing influential parameters affecting the reproduction number. Numerical simulations showed that methicillin may increase the population of co-infected cells, while azithromycin can improve the host immune response but has limited impact on MRSA proliferation. Increased efficacy of vancomycin can lead to MRSA eradication. Combination of immunomodulatory antibiotics and vancomycin has minimal effect on co-infected cell population, but increased vancomycin efficacy can reduce coinfection severity. This study emphasizes the importance of continuous research, surveillance, and the development of effective strategies to combat the complexities of COVID-19 and MRSA coinfection.

Smartphone-triggered targeted inactivation of MRSA under SERS monitoring

Silver nanoparticles-based multifunctional agents show tremendous potential for simultaneous imaging and against the methicillin-resistant Staphylococcus aureus (MRSA)-induced superficial infection. However, it is still a challenge to achieve a balance between high precision, high antibacterial efficiency, and biocompatibility. Herein, we present a 4-mercaptophenylboronic acid (4-MPBA)-modified Ag2CO3/Ag2O nano-heterojunctions (AgH@M) that can recognize single MRSA cell by surface-enhanced Raman scattering (SERS) and effectively eradicate MRSA under smartphone irradiation. Moreover, the 4-MPBA molecule acts as triple identities for MRSA targeted binding, SERS tag, and inhibition of excessive release of toxic silver ions for the Raman Imaging guided bacterial treatment. AgH@M simultaneously targeted binding on the surface of bacteria and made full use of the released limited Ag+ into the MRSA, thereby reducing the toxicity to mammalian cells. In addition, the potential antibacterial mechanism involves ROS production from photocatalytic behavior, interference with functional genes of quorum sensing, virulence, biofilm, and ATP-binding cassette transporter. Also, the AgH@M can monitor the residual bacteria in MRSA-infected wounds and keratitis animal models in real-time for at least 7 days by SERS and accomplishes a satisfactory therapeutic effect. This work may provide promising visualized heterojunctions for the targeted eradication of MRSA with a portable light source.

The Comparative Efficacy of Tea Tree Oil Body Wash versus Chlorhexidine Body Wash to Prevent Colonization with Methicillin-Resistant Staphylo-coccus Aureus in a Pediatric Unit

Background: Methicillin-resistant Staphylococcus Aureus (MRSA) stands for methicillin-resistant Staphylococcus aureus, a type of bacteria that is resistant to several antibiotics. Non-intact skin, such as when there are abrasions or incisions, is often the site of an MRSA infection. MRSA has become endemic in hospitals over the past years. The current recommendation for MRSA decolonization is to use a daily chlorohexidine skin wash for five days. Tea Tree Oil (TTO) can also be considered for the eradication of MRSA on the skin. However, no study has evaluated the TTO potential for MRSA decolonization in hospitalized children.
 Methods:In this single-center, comparative prospective, open-label clinical trial, the effect of TTO body wash on MRSA decolonization was compared to that of chlorhexidine body wash at Loghman-e-Hakim Hospital (Tehran, Iran). Several samples were taken from the catheter sites of children for MRSA detection. Patients were assigned to receive either TTO or chlorhexidine. After five days of applying the solutions, resampling was conducted to assess the colonization of MRSA.
 Results: Both TTO and chlorhexidine groups showed favorable results for MRSA decolonization. From 382 patients, 91 were MRSA-positive (about 23.82%), and of these 91 patients, 41 (45%) were female and 59 (55%) were male. The mean ± SD of the growth inhibition zone against MRSA was 19.20 ± 3.73 and 33.41 ± 9.53 for chlorhexidine and TTO, respectively.
 Conclusion: TTO body wash proved to be more effective than chlorhexidine in MRSA decolonization in hospitalized children. Implementation of such decolonization can improve patients’ outcomes and prevent MRSA transmission.

Bacteria-mimetic nanomedicine for targeted eradication of intracellular MRSA

Drug-resistant infections caused by intracellular bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), which are often hidden inside macrophages, pose a significant threat to human health. Various nanomedicines have been developed to combat intracellular MRSA; however, their poor uptake and fast clearance from macrophages often result in insufficient enrichment of antibacterial agents intracellularly, leading to low antibacterial efficacy. Here, we developed bacterial membrane-coated mesoporous SiO2 nanoparticles (MSN) loaded with vancomycin (Van), a classic antibiotic. These nanoparticles can be specifically recognized and internalized by macrophages and self-aggregated into micron-sized MSN clusters based on cucurbit[7]uril-adamantane host-guest interactions, allowing for slow clearance and extended retention in infected macrophages. The acid-triggered, sustainable release of Van from MSN aggregates effectively killed MRSA in infected macrophages and significantly alleviated inflammation caused by intracellular bacterial infections both in vitro and in vivo. This work not only provides a practical solution to effectively treat drug-resistant intracellular infections but also offers new insights for the design and development of antibacterial nanomaterials.

Disinfection of methicillin-resistant Staphylococcus Aureus on flat surface by 460 nm light and hydrogen peroxide combination

Staphyloxanthin (STX) is a carotenoid pigment produced by Staphylococcus aureus to protect the bacteria from oxidation stress. Eliminating Staphyloxanthin from S. aureus cell membrane by inducing the pigment photolysis using 460nm light, then killing weakened bacteria with an H2O2 solution could be a new approach to develop anti - Staphylococcus aureus procedure. A model to prove the feasibility of this combination to kill Methicillin-Resistant Staphylococcus Aureus (MRSA) bacteria on a flat surface was tested. Material and method: Staphyloxanthin pigment extracted from MRSA bacteria was treated with 460nm light at different light intensities to evaluate the photolysis potential of 460nm light. The change in MRSA shape after 460nm light treatment was also investigated by Scanning electron microscopy. Using glass cover-slips as an emulated model for contact surface in public, the combination of different 460nm light intensities and H2O2 0.75% was tested on the surface loaded with MRSA living cells, and the number of MRSA cells survived after treatment was enumerated. Result: Higher intensity and longer light treatment yielded a higher photolysis effect, as 100 and 200 mW/cm2 light intensity could degrade 77.50% to 83.45% of STX pigment after 20 minutes of irradiation. Also, MRSA cells had significant changes as more wrinkles and bumps appeared under high-intensity 460nm light. When tested on the flat surface of the coverslip, the strongest MRSA eradication effect can be observed in the combination of 200 mW/cm2 light treatment with 0.75% H2O2 solution, as 100% MRSA cells were completely killed after 20 minutes of treatment.

Antimicrobial photodynamic therapy with Ligularia fischeri against methicillin-resistant Staphylococcus aureus infection in Caenorhabditis elegans model

The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection threatens the effectiveness of current clinical settings. Antimicrobial photodynamic therapy (APDT) is a promising alternative to antibiotics for treating infections due to its low resistance. This study aimed to evaluate the antibacterial properties of APDT with L. fischeri extract (LFE) against MRSA and various skin and oral pathogens in vitro and its photopharmaceutical actions in Caenorhabditis elegans. The antimicrobial activities of APDT with LFE against pathogens were evaluated using plate counting method. The chemical profile was characterized using high-performance liquid chromatography and spectrophotometry. The growth rate assay, lifespan assay, and bacterial attachment on worms were performed to assess the therapeutics effects in C. elegans. The swab method was used for the detection of pathogens on the micropig skin surface. The APDT treatment with L. fischeri extract (LFE, 20 µg/mL) and red light (intensity of 120 W/m2) reduced 4.3–4.9 log (colony forming unit/mL) of Staphylococcus aureus, MRSA, Cutibacterium acnes, Streptococcus mutans; and 2.4 log (CFU/mL) of Candida albicans. Chemical analysis revealed that LFE enriched three active photosensitizers. APDT reduced bacterial populations on worms, recovered growth retardation, and improved lifespan in MRSA-infected C. elegans without causing severe side effects. The surface eradication of MRSA after exposure to LFE with red light was demonstrated on micropig skin. These findings highlight the significance of L. fischeri as a natural resource for the safe phototreatment of MRSA infection in the biomedical and cosmeceutical industries.

Polymeric nano-system for macrophage reprogramming and intracellular MRSA eradication.

Intracellular Methicillin-Resistant Staphylococcus aureus (MRSA) remains a major factor of refractory and recurrent infections, which cannot be well addressed by antibiotic therapy. Here, we design a cellular infectious microenvironment-activatable polymeric nano-system to mediate targeted intracellular drug delivery for macrophage reprogramming and intracellular MRSA eradication. The polymeric nano-system is composed of a ferrocene-decorated polymeric nanovesicle formulated from poly(ferrocenemethyl methacrylate)-block-poly(2-methacryloyloxyethyl phosphorylcholine) (PFMMA-b-PMPC) copolymer with co-encapsulation of clofazimine (CFZ) and interferon-γ (IFN-γ). The cellular-targeting PMPC motifs render specific internalization by macrophages and allow efficient intracellular accumulation. Following the internalization, the ferrocene-derived polymer backbone sequentially undergoes hydrophobic-to-hydrophilic transition, charge reversal and Fe release in response to intracellular hydrogen peroxide over-produced upon infection, eventually triggering endosomal escape and on-site cytosolic drug delivery. The released IFN-γ reverses the immunosuppressive status of infected macrophages by reprogramming anti-inflammatory M2 to pro-inflammatory M1 phenotype. Meanwhile, intracellular Fe2+-mediated Fenton reaction together with antibiotic CFZ contributes to increased intracellular hydroxyl radical (•OH) generation. Ultimately, the nano-system achieves robust potency in ablating intracellular MRSA and antibiotic-tolerant persisters by synchronous immune modulation and efficient •OH killing, providing an innovative train of thought for intracellular MRSA control.

Exploring the Barriers in the Uptake of the Dutch MRSA 'Search and Destroy' Policy Using the Cascade of Care Approach.

The Dutch ‘search and destroy’ policy consists of screening patients with an increased risk of methicillin-resistant Staphylococcus aureus (MRSA) carriership and subsequent decolonization treatment when carriership is found. Decolonization therapy of individual MRSA carriers is effective. However, the effectiveness of the national ‘search and destroy’ policy is dependent on the entire cascade of care, including identification, referral, and subsequent treatment initiation in MRSA carriers. The aim of this study was to evaluate the leakages in the cascade of MRSA decolonization care. We assessed familiarity with the ‘search and destroy’ policy and the barriers in the uptake of MRSA eradication care using a questionnaire among 114 Dutch general practitioners. The main reasons for treatment were planned hospital visits, occupational reasons, and infections. The main reasons for refraining from eradication treatment were unfamiliarity with the ‘search and destroy’ policy and the assumption that MRSA carriership is often self-limiting. To optimize the continuity of the cascade of care, interventions should be aimed at supporting general practitioners and facilitating treatment and referral.

Intra-articular versus systemic vancomycin for the treatment of periprosthetic joint infection after debridement and spacer implantation in a rat model.

AimsTreatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.MethodsTotal knee arthroplasty (TKA), MRSA inoculation, debridement, and vancomycin-spacer implantation were performed successively in rats to mimic first-stage PJI during the two-stage revision arthroplasty procedure. Vancomycin was administered intraperitoneally or intra-articularly for two weeks to control the infection after debridement and spacer implantation.ResultsRats receiving intra-articular vancomycin showed the best outcomes among the four treatment groups, with negative bacterial cultures, increased weight gain, increased capacity for weightbearing activities, increased residual bone volume preservation, and reduced inflammatory reactions in the joint tissues, indicating MRSA eradication in the knee. The vancomycin-spacer and/or systemic vancomycin failed to eliminate the MRSA infections following a two-week antibiotic course. Serum vancomycin levels did not reach nephrotoxic levels in any group. Mild renal histopathological changes, without changes in serum creatinine levels, were observed in the intraperitoneal vancomycin group compared with the intra-articular vancomycin group, but no changes in hepatic structure or serum alanine aminotransferase or aspartate aminotransferase levels were observed. No local complications were observed, such as sinus tract or non-healing surgical incisions.ConclusionIntra-articular vancomycin injection was effective and safe for PJI control following debridement and spacer implantation in a rat model during two-stage revision arthroplasties, with better outcomes than systemic vancomycin administration.Cite this article: Bone Joint Res 2022;11(6):371–385.

Prospective surveillance of colonization and disease by methicillin-resistant Staphylococcus aureus (MRSA) at a European pediatric cancer center

PurposeChildren and adolescents undergoing treatment for cancer or allogeneic hematopoietic cell transplantation are at increased risk for methicillin-resistant Staphylococcus aureus (MRSA). We therefore examined the occurrence and outcome of MRSA colonization and infection in patients of a large European pediatric cancer center.MethodsIn a prospective observational cohort study conducted between 2007 and 2018, nasopharyngeal swabs for culture of MRSA were obtained from all admitted patients. The primary endpoint of the study was the colonization rate over time. Secondary endpoints included genetic relatedness of isolates, time burden of isolation measures, and results of decolonization efforts.ResultsDuring the study period, MRSA screening identified 34 colonized patients (median age: 10 years; range: 0–21) without trends over time. MRSA colonization was associated with the presence of classical risk factors. There was no molecular evidence of patient-to-patient transmission. A standard MRSA eradication regimen led to a lasting eradication of the organism in 26 of 34 patients. MRSA infection occurred in two patients with no associated fatalities.ConclusionProspective monitoring revealed low rates of MRSA colonization and infection at our center. These low rates and the absence of patient-to-patient transmission support the effectiveness of the management bundle of MRSA identification, isolation, and decolonization.

In vitro study examining the effectiveness of antiseptic prophylaxis for antibiotic-resistant bacterial endophthalmitis.

To assess the effectiveness of current antiseptic agents on multidrug-resistant (MDR) isolates in an in vitro setting. Department of Microbiology, The National Maternity Hospital, Dublin, Ireland. Organisms were selected based on current review of endophthalmitis literature: methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), Pseudomonas aeruginosa, carbapenem-resistant and extended-spectrum β-lactamase Klebsiella pneumoniae, and vancomycin-resistant (VRE) Enterococcus faecalis. Samples were exposed to povidone-iodine (PVI) 5% and chlorhexidine (CHX) 0.05% for 0.5 minutes, 1 minute, 3 minutes, and 5 minutes. After inactivation, organisms were incubated under standard conditions and growth assessed after 16 hours. MRSA and MRSE responded to 3-minute PVI exposure. CHX eradicated MRSA growth after 5 minutes but failed to completely suppress MRSE. Pseudomonas and Klebsiella required 3-minute CHX exposure and 5-minute PVI exposure for complete clearance. Eradication of enterococci (VRE positive and negative) was not achieved at 10 minutes of CHX or PVI exposure. Comparison of PVI vs CHX showed a benefit for PVI in MRSA (P < .01) and MRSE (P < .001) eradication at 3 minutes. Current recommendations of 3 minutes of antisepsis prior to intraocular surgery are not sufficient for complete eradication of MDR organisms from the ocular surface. A bespoke approach is suggested to patients at risk for carriage of MDR organisms to minimize the risk of endophthalmitis.

Efficacy and safety of novel glycopeptides versus vancomycin for the treatment of gram-positive bacterial infections including methicillin resistant Staphylococcus aureus: A systematic review and meta-analysis.

ObjectiveTo compare between current evidence of novel glycopeptides against vancomycin for the treatment of gram-positive bacterial infections.MethodologyA systematic review and meta-analysis was done. Major databases were searched for eligible randomized control trials that assessed clinical success, microbiological success and safety profile of novel glycopeptides versus vancomycin for infections caused by gram-positive bacteria.ResultsThis meta-analysis included eleven trials (7289 participants) comparing telavancin, dalbavancin and oritavancin with vancomycin. No differences were detected between novel glycopeptides and vancomycin for the treatment of skin and soft tissue infections (SSTIs) among modified intent-to-treat patients (OR: 1.04, CI: 0.92–1.17) as well as within the clinically evaluable patients (OR: 1.09, CI: 0.91–1.30). Data analysed from SSTIs, HAP and bacteremia studies on telavancin showed insignificant high clinical response in microbiologically evaluable patients infected with methicillin resistant Staphylococcus aureus (MRSA) (OR: 1.57, CI: 0.94–2.62, p: 0.08) and in the eradication of MRSA (OR: 1.39, CI: 0.99–1.96, P:0.06). Dalbavancin was non-inferior to vancomycin for the treatment of osteomyelitis in a phase II trial, while it was superior to vancomycin for the treatment of bacteremia in a phase II trial. Data analysed from all trials showed similar rates of all-cause mortality between compared antibiotics groups (OR: 0.67, CI: 0.11–4.03). Telavancin was significantly related with higher adverse events (OR: 1.24, CI: 1.07–1.44, P: <0.01) while dalbavancin and oritavancin were associated with significant fewer adverse events (OR: 0.73, CI: 0.57–0.94, p: 0.01; OR: 0.72, CI: 0.59–0.89, p: <0.01 respectively).ConclusionEfficacy and safety profiles of both dalbavancin and oritavancin were the same as vancomycin in the treatment of gram-positive bacterial infections in different clinical settings, while telavancin might be an effective alternative to vancomycin in MRSA infections, but caution is required during its clinical use due to the high risk of adverse events, especially nephrotoxicity.

Pharmacokinetics, Tissue Distribution, and Efficacy of VIO-001 (Meropenem/Piperacillin/Tazobactam) for Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia in Immunocompetent Rabbits with Chronic Indwelling Vascular Catheters.

Methicillin-resistant Staphylococcus aureus (MRSA) infections of surgically implanted subcutaneous vascular catheters (SISVCs) cause serious morbidity in patients with chronic illnesses. Previous in vitro and murine models demonstrated the synergistic interaction of equimolar concentrations of meropenem/piperacillin/tazobactam (MPT) (VIO-001) against MRSA infection. We investigated the pharmacokinetics (PK) and efficacy of VIO-001 for the treatment of MRSA bacteremia in immunocompetent rabbits with SISVCs. In PK studies, we determined that optimal dosing to achieve a time above 4× MIC (T>4×MIC) of a duration of 3 to 3.30 h required a 1-h infusion with every-4-h (Q4h) dosing. Study groups in efficacy experiments consisted of MPT combinations of 100/150/100 mg/kg of body weight (MPT100), 200/300/200 mg/kg (MPT200), and 400/600/400 mg/kg (MPT400); vancomycin (VAN) at 15 mg/kg; and untreated controls (UC). The inoculum of MRSA isolate USA300-TCH1516 (1 × 103 organisms) was administered via the SISCV on day 1 and locked for 24 h. The 8-day therapy started at 24 h postinoculation. There was a significant reduction of MRSA in blood cultures from the SISVCs in all treatment groups, with full clearance on day 4, versus UCs (P < 0.05). Consistent with the clearance of SISVC-related infection, full eradication of MRSA was achieved in lungs, heart, liver, spleen, and kidneys at the end of the study versus UC (P < 0.01). These results strongly correlated with time-kill data, where MPT in the range of 4/6/4 μg/ml to 32/48/32 μg/ml demonstrated a significant 6-log decrease in the bacterial burden versus UC (P < 0.01). In summary, VIO-001 demonstrated a favorable PK/pharmacodynamic (PD) profile and activity against SISCV MRSA infection, bacteremia, and disseminated infection. This rabbit model provides a new system for understanding new antimicrobial agents against MRSA SISVC-related infection, and these data provide a basis for future clinical investigation.

DNA Aptamer-Conjugated Magnetic Graphene Oxide for Pathogenic Bacteria Aggregation: Selective and Enhanced Photothermal Therapy for Effective and Rapid Killing.

Methicillin-resistant Staphylococcus aureus (MRSA), often called “superbug”, is a nosocomial and multidrug resistance bacterium that shows resistance to β-lactam antibiotics. There has been high demand to develop an alternative treatment model to antibiotics for efficiently fighting MRSA. Herein, we developed DNA aptamer-conjugated magnetic graphene oxide (Apt@MGO) as a multifunctional and biocompatible nanoplatform for selective and rapid eradication of MRSA and evaluated heat generation and cell death performance of Apt@MGO for the first time under dispersed and aggregated states. The aptamer sequence was specifically selected for MRSA and acted as a molecular targeting probe for selective MRSA recognition and antibiotic-free therapy. Magnetic graphene oxide (MGO) serves as a nanoplatform for aptamer conjugation and as a photothermal agent by converting near-infrared (NIR) light to heat. Iron oxide nanoparticles (Fe3O4 NPs) are formed on GO to prepare MGO, which shows magnetic properties for collecting MRSA cells in a certain area in the reaction tube by an external magnet. The collected MGO induces remarkably high local heating and eventual MRSA cell death under NIR laser irradiation. We demonstrate that Apt@MGO resulted in ∼78% MRSA and over >97% MRSA cell inactivation in dispersed and aggregated states, respectively, under 200 seconds (sn) exposure of NIR irradiation (808 nm, 1.1 W cm–2). An in vitro study highlights that Apt@MGO is considered a targeted, biocompatible, and light-activated photothermal agent for efficient and rapid killing of MRSA in the aggregated state under NIR light.

Comparative Evaluation of Linezolid and Teicoplanin in the Treatment of Ventilator-Associated MRSA Pneumonia: A Single-Center Experience

Background: Ventilator-associated pneumonia (VAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) is a serious infection in an intensive care unit (ICU). Ventilator-associated MRSA pneumonia (VAMP) in critically ill patients causes a high rate of mortality. Objectives: This study mainly aimed to compare the clinical outcomes and associated drug safety perspective of linezolid and teicoplanin in VAMP treatment. Methods: This retrospective study included 98 adult ICU patients with VAMP, where 42 patients (LZD group) and 56 patients (TPN group) received a standard dose of linezolid and teicoplanin, respectively, for their VAMP treatment. Adverse reactions associated with linezolid and teicoplanin were considered. Clinical outcomes and 30-day mortality rates were compared in both groups. Results: The LZD group showed a higher MRSA eradication rate (97%, n = 34) than the TPN group (94.3%, n = 53) (P = 0.034). The linezolid and teicoplanin therapy was suddenly discontinued in 19% and 5.3% of the patients in the LZD and TPN groups, respectively, before completing the full duration of antibiotic therapy due to developed adverse drug reactions (ADRs), including thrombocytopenia (LZD/TPN groups: 7/1 event), tachycardia (LZD group: 1 event), and nephrotoxicity (TPN group: 2 events). This discontinuation increased the total duration of antibiotic therapy in 19% (n = 42) and 5.3% (n = 56) of the patients (P = 0.034) in the LZD and TPN groups, respectively. Conclusions: VAMP is a life-threatening event in critically ill ICU patients worldwide. In this study, teicoplanin showed better clinical outcomes with a certain higher level of drug safety compared to linezolid in the treatment of ventilator-associated MRSA pneumonia.

Perceptions of Dutch nurses carrying methicillin-resistant Staphylococcus aureus: a qualitative study

BackgroundCarriers of methicillin-resistant Staphylococcus aureus (MRSA) experience a variety of personal and social consequences, despite the asymptomatic nature of carriage. Some of these consequences are inherent to the application in practice of strict infection prevention guidelines. However, the experiences of nurses carrying MRSA have not been documented. This study aimed to describe the experiences of nurses carrying MRSA to get insight into the impact of MRSA carriage on nurses in a country with a “search-and-destroy” policy for MRSA.MethodsA qualitative study was conducted among eighteen nurses who experienced MRSA carriage and were working in healthcare organizations in the Netherlands (e.g. hospitals, nursing homes and home care). Semi-structured interviews were conducted using an interview guide. The interviews were audio tape recorded, transcribed and analyzed using thematic analysis.ResultsMRSA carriage has an impact on the life of nurses during four distinct phases: becoming aware of carrying MRSA, processing information and guidance, experiencing consequences of carriage and, when applicable, a life after eradication of MRSA. Each phase was found to be associated with negative consequences. The impact of MRSA carriage on the daily life of nurses is mostly influenced by the experience of consequences of MRSA carriage – including a ban to work with patients, eradication treatment with antibiotics, and social isolation from others – despite the asymptomatic nature of MRSA carriage itself. In addition, lack of information and guidance increased the impact of carriage.ConclusionsThis study shows nurses experience various consequences of MRSA carriage, despite the asymptomatic nature of carriage. The work ban, eradication treatment and social isolation influenced the nurses’ work-related future, personal health and social environment. The impact of carriage may be reduced by clear information and guidance, and support from others. Therefore, sufficient information and guidance needs to be given to MRSA carriers by healthcare organizations.

Methicillin-Resistant Staphylococcus aureus Eradication and Decolonization in Children Study (Part 2): Patient- and Parent-Centered Outcomes of Decolonization.

BackgroundSkin and soft tissue infections (SSTIs) due to community-acquired methicillin-resistant Staphylococcus aureus (MRSA) can lead to a number of significant known medical outcomes including hospitalization, surgical procedures such as incision and drainage (I&D), and the need for decolonization procedures to remove the bacteria from the skin and nose and prevent recurrent infection. Little research has been done to understand patient and caregiver-centered outcomes associated with the successful treatment of MRSA infection.ObjectiveThis study aimed to uncover MRSA decolonization outcomes that are important to patients and their parents in order to create a set of prototype measures for use in the MRSA Eradication and Decolonization in Children (MEDiC) study.MethodsA 4-hour, human-centered design (HCD) workshop was held with 5 adolescents (aged 10-18 years) who had experienced an I&D procedure and 11 parents of children who had experienced an I&D procedure. The workshop explored the patient and family experience with skin infection to uncover patient-centered outcomes of MRSA treatment. The research team analyzed the audio and artifacts created during the workshop and coded for thematic similarity. The final themes represent patient-centered outcome domains to be measured in the MEDiC comparative effectiveness trial.ResultsThe workshop identified 9 outcomes of importance to patients and their parents: fewer MRSA outbreaks, improved emotional health, improved self-perception, decreased social stigma, increased amount of free time, increased control over free time, fewer days of school or work missed, decreased physical pain and discomfort, and decreased financial burden.ConclusionsThis study represents an innovative HCD approach to engaging patients and families with lived experience with MRSA SSTIs in the study design and trial development to determine meaningful patient-centered outcomes. We were able to identify 9 major recurrent themes. These themes were used to develop the primary and secondary outcome measures for MEDiC, a prospectively enrolling comparative effectiveness trial.Trial RegistrationClinicalTrials.gov NCT02127658; https://clinicaltrials.gov/ct2/show/NCT02127658

Pilot Study of Aerosolised Plus Intravenous Vancomycin in Mechanically Ventilated Patients with Methicillin-Resistant Staphylococcus Aureus Pneumonia.

Treatment of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in critically ill patients remains unsatisfactory. This pilot study aimed to evaluate the clinical outcomes of aerosolised vancomycin in addition to intravenous administration in this setting. This was a prospective, noncomparative, phase II trial. Patients receiving mechanical ventilation for >48 h in intensive care units (ICUs) were screened; those receiving intravenous vancomycin for MRSA pneumonia were enrolled. Patients received aerosolised vancomycin (250 mg every 12 h for five days) via a vibrating mesh nebuliser. The primary outcome was treatment success (clinical cure or improvement) at the conclusion of antibiotic treatment. Vancomycin concentrations were measured in bronchoalveolar lavage fluid according to administration time. Twenty patients were enrolled (median age 75 years and 13 (65%) men; 18 (90%) cases with nosocomial pneumonia). Thirteen patients (65%) showed clinical cure or improvement. Microbiological eradication of MRSA was confirmed in 14 patients (70%). ICU and hospital mortality rates were 30% and 35%, respectively. Maximum aerosolised vancomycin concentration was observed 4–5 h after nebulising (98.75 ± 21.79 mcg/mL). No additional systemic adverse effects occurred following aerosol vancomycin treatment. Aerosolised vancomycin combination therapy may be an alternative treatment for patients with severe MRSA pneumonia receiving mechanical ventilation (ClinicalTrials.gov number, NCT01925066).