A carrier-free, injectable, and self-assembling hydrogel based on carvacrol and glycyrrhizin exhibits high antibacterial activity and enhances healing of MRSA-infected wounds.

Inspired by glycyrrhizin's strong pharmacological activities and the directed self-assembly into hydrogels, we created a novel carrier-free, injectable hydrogel (CAR@glycygel) by combining glycyrrhizin with carvacrol (CAR), without any other chemical crosslinkers, to promote wound healing on bacteria-infected skin. CAR appeared to readily dissolve and load into CAR@glycygel. CAR@glycygel had a dense, porous, sponge structure and strong antioxidant characteristics. In vitro, it showed better antibacterial ability than free CAR. For methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Escherichia coli, the diameter of inhibition zone values of CAR@glycygel were 3.80 ± 0.04, 3.31 ± 0.20 and 3.12 ± 0.24 times greater, respectively, than those of free CAR. The MICs for CAR@glycygel was 156.25 µg/mL while it was 1250.00 µg/mL for free CAR to these three bacteria. Its antibacterial mechanism appeared to involve destruction of the integrity of the bacterial cell wall and biomembrane, leading to a leakage of AKP and inhibition of biofilm formation. In vivo, CAR@glycygel effectively stopped bleeding. When applied to skin wounds on rats infected with MRSA, CAR@glycygel had strong bactericidal activity and improved wound healing. The wound healing rates for CAR@glycygel were 49.59 ± 15.78 %, 93.02 ± 3.09 % and 99.02 ± 0.55 % on day 3, day 7, and day 11, respectively, which were much better than blank control and positive control groups. Mechanisms of CAR@glycygel accelerating wound healing involved facilitating epidermis remolding, promoting the growth of hair follicles, stimulating collagen deposition, mitigating inflammation, and promoting angiogenesis. Overall, CAR@glycygel showed great potential as wound dressing for infected skin wounds.

A Single Lung Abscess Caused by Panton-Valentine Leukocidin-Producing Methicillin-Resistant Staphylococcus aureus.

This case report presents a rare occurrence of a single lung abscess caused by Panton-Valentine leukocidin (PVL)-producing methicillin-resistant Staphylococcus aureus (MRSA) in a 38-year-old immunocompetent man. The patient, of Southeast Asian origin, presented with symptoms of fever, chest pain, cough, and shortness of breath following a recent flu-like illness. Imaging indicated a cavitary lung lesion in the left lower lobe, suggestive of a lung abscess. Initial antibiotic treatment failed, and drainage of the abscess confirmed MRSA with the PVL gene, indicating a community-acquired MRSA infection. The patient received intravenous vancomycin followed by oral linezolid, leading to the resolution of the abscess. Contact tracing and decolonization measures were implemented. This case highlights the importance of considering PVL-producing S. aureus as a potential pathogen in severe necrotizing pneumonia or sepsis and underscores the need for prompt diagnosis, appropriate antibiotic therapy, and infection control measures in managing such infections.

Atypical cutaneous manifestations of methicillin resistant Staphylococcus aureus infections in two immunocompetent pediatric patients: Case reports and review of the literature.

Although many clinical variants of Staphylococcus aureus infection are well-recognized, atypical presentations may mimic other conditions. We describe two cases of atypical S. aureus infections in pediatric patients: a S. aureus infection presenting with a vesicopustular rash mimicking varicella zoster virus and a case of multifocal panniculitis. Both of these cases were specifically caused by methicillin-resistant S. aureus (MRSA). Additional cases of atypical S. aureus infections and presenting features from the current literature are also discussed.

Extracellular vesicles from alveolar macrophages harboring phagocytosed methicillin-resistant Staphylococcus aureus induce necroptosis.

Methicillin-resistant Staphylococcus aureus (MRSA) infection, a major cause of hospital- and community-acquired pneumonia, still has a high mortality rate. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, have a significant impact on infectious diseases. However, the role of EVs from alveolar macrophages (AMs) in MRSA pneumonia remains unclear. We report that AMs phagocytose MRSA and release more EVs in mice with MRSA pneumonia. EVs from AMs harboring phagocytosed MRSA exhibit significant proinflammatory effects and induce necroptosis by delivering tumor necrosis factor α (TNF-α) and miR-146a-5p. Mechanically, the upregulated miR-146a-5p in these EVs enhances the phosphorylation of RIPK1, RIPK3, and MLKL by targeting TNF receptor-associated factor 6 (TRAF6), thereby promoting TNF-α-induced necroptosis. The combination of a TNF-α antagonist and an miR-146a-5p antagomir effectively improves the outcomes of mice with MRSA pneumonia. Overall, we reveal the pronecrotic effect of EVs from MRSA-infected AMs and provide a promising target for the prevention and treatment of MRSA pneumonia.

The burden of antibiotic resistance of the main microorganisms causing infections in humans - review of the literature.

One of the biggest threats to human well-being and public health is antibiotic resistance. If allowed to spread unchecked, it might become a major health risk and trigger another pandemic. This proves the need to develop antibiotic resistance-related global health solutions that take into consideration microdata from various global locations. Establishing positive social norms, guiding individual and group behavioral habits that support global human health, and ultimately raising public awareness of the need for such action could all have a positive impact. Antibiotic resistance is not just a growing clinical concern but also complicates therapy, making adherence to current guidelines for managing antibiotic resistance extremely difficult. Numerous genetic components have been connected to the development of resistance; some of these components have intricate paths of transfer between microorganisms. Beyond this, the subject of antibiotic resistance is becoming increasingly significant in medical microbiology as new mechanisms underpinning its development are identified. In addition to genetic factors, behaviors such as misdiagnosis, exposure to broad-spectrum antibiotics, and delayed diagnosis contribute to the development of resistance. However, advancements in bioinformatics and DNA sequencing technology have completely transformed the diagnostic sector, enabling real-time identification of the components and causes of antibiotic resistance. This information is crucial for developing effective control and prevention strategies to counter the threat.

Elucidating the potential of isorhapontigenin in targeting the MgrA regulatory network: a paradigm shift for attenuating MRSA virulence.

As methicillin-resistant Staphylococcus aureus (MRSA) exhibits formidable resistance to many drugs, the imperative for alternative therapeutic strategies becomes increasingly evident. At the heart of our study is the identification of a novel inhibitor through fluorescence anisotropy assays, specifically targeting the crucial multiple gene regulator A (MgrA) regulatory network in S. aureus. Isorhapontigenin (Iso), a natural compound, exhibits outstanding inhibitory efficacy, modulating bacterial virulence pathways without exerting direct bactericidal activity. This suggests a paradigm shift toward attenuating virulence instead of purely focusing on bacterial elimination. Through comprehensive in vitro and in vivo evaluations, we elucidated the complex interplay between Iso and MgrA, leading to reduced S. aureus adhesion, and overall virulence. At the cellular level, Iso offers significant protection to A549 cells infected with S. aureus, reducing cellular damage. Importantly, Iso augments the chemotaxis of neutrophils, curtailing the immune evasion capabilities of S. aureus. Furthermore, in vivo investigations highlight the notable effectiveness of Iso against MRSA-induced pneumonia and within the Galleria mellonella infection model, underscoring its pivotal role in the evolving realm of antibacterial drug discovery. Significantly, when Iso is used in combination with vancomycin, it outperforms its solo application, indicating a more pronounced therapeutic impact. This seminal research emphasizes Iso's potential as a primary defense against the surge of multidrug-resistant pathogens, heralding new prospects in antimicrobial therapy.

ST913-IVa-t991 Methicillin-Resistant Staphylococcus aureus among Pediatric Patients, Israel.

In Israel, prevalence of sequence type 913, staphylococcal cassette chromosome mecIVa, spa type t991 methicillin-resistant Staphylococcus aureus lineage has surged among pediatric populations, predominantly in Arab and Orthodox Jewish communities. Antimicrobial resistance patterns vary by demographics. This lineage's spread and microevolution in the Middle East underscore the need for ongoing surveillance.

Performance evaluation of cefoxitin screen test on two different automated antimicrobial susceptibility test systems: a comparative study.

Reliable detection of mecA and mecC-mediated beta-lactam resistance using automated antimicrobial susceptibility test systems is critical for patient care. The aim of this study was to compare the performance of the new cefoxitin screen test (oxsf02n) on the Vitek 2 card (Vitek 2) and BD Phoenix PMC-100 Gram-Positive AST Panel (Phoenix) against the reference method for the detection of mecA (and mecC)-mediated beta-lactam resistance. Two hundred fifty clinical fresh and stock Staphylococcus spp. isolates were included. There were 120 mecA-positive, 10 mecC-positive, and 120 mecA and mecC-negative isolates. Cefoxitin screen and oxacillin tests were performed on Vitek 2 and Phoenix and by their respective reference methods (disk diffusion for the cefoxitin screen test and broth microdilution for oxacillin) for all isolates. PCR testing was also performed to confirm the presence of mecA and/or mecC genes. Results from each system were compared to the reference methods. Statistical hypotheses were evaluated both for Vitek 2 compared to the reference methods and Vitek 2 compared to the Phoenix. Compared to the reference method, the Vitek 2 cefoxitin screen test had 100% sensitivity/98% specificity and the Phoenix cefoxitin screen test had 84% sensitivity/100% specificity for the detection of mecA (and mecC)-mediated beta-lactam resistance. When the oxacillin test was combined with the cefoxitin screen for Vitek 2, the sensitivity and specificity were unchanged. However, when the oxacillin and cefoxitin screen tests were combined for the Phoenix, the sensitivity increased to 100% and the specificity remained unchanged (100%). When considering cefoxitin alone, the Vitek 2 screen test showed a higher sensitivity than the Phoenix for the detection of mecA and mecC-mediated beta-lactam resistance. However, currently, both systems use a combination of the cefoxitin and oxacillin tests to interpret the final result, and both reached a high level of performance when cefoxitin and oxacillin results were combined.IMPORTANCEThis research marks the inaugural evaluation of the revamped cefoxitin screen test version in Vitek 2, juxtaposing it against reference methods and a primary competitor BD Phoenix.

Antibacterial and antibiofilm potentials of vancomycin-loaded niosomal drug delivery system against methicillin-resistant Staphylococcus aureus (MRSA) infections.

The threat of methicillin-resistant Staphylococcus aureus (MRSA) is increasing worldwide, making it significantly necessary to discover a novel way of dealing with related infections. The quick spread of MRSA isolates among infected individuals has heightened public health concerns and significantly limited treatment options. Vancomycin (VAN) can be applied to treat severe MRSA infections, and the indiscriminate administration of this antimicrobial agent has caused several concerns in medical settings. Owing to several advantageous characteristics, a niosomal drug delivery system may increase the potential of loaded antimicrobial agents. This work aims to examine the antibacterial and anti-biofilm properties of VAN-niosome against MRSA clinical isolates with emphasis on cytotoxicity and stability studies. Furthermore, we aim to suggest an effective approach against MRSA infections by investigating the inhibitory effect of formulated niosome on the expression of the biofilm-associated gene (icaR). The thin-film hydration approach was used to prepare the niosome (Tween 60, Span 60, and cholesterol), and field emission scanning electron microscopy (FE-SEM), an in vitro drug release, dynamic light scattering (DLS), and entrapment efficiency (EE%) were used to investigate the physicochemical properties. The physical stability of VAN-niosome, including hydrodynamic size, polydispersity index (PDI), and EE%, was analyzed for a 30-day storage time at 4 °C and 25 °C. In addition, the human foreskin fibroblast (HFF) cell line was used to evaluate the cytotoxic effect of synthesized niosome. Moreover, minimum inhibitory and bactericidal concentrations (MICs/MBCs) were applied to assess the antibacterial properties of niosomal VAN formulation. Also, the antibiofilm potential of VAN-niosome was investigated by microtiter plate (MTP) and real-time PCR methods. The FE-SEM result revealed that synthesized VAN-niosome had a spherical morphology. The hydrodynamic size and PDI of VAN-niosome reported by the DLS method were 201.2 nm and 0.301, respectively. Also, the surface zeta charge of the prepared niosome was - 35.4 mV, and the EE% ranged between 58.9 and 62.5%. Moreover, in vitro release study revealed a sustained-release profile for synthesized niosomal formulation. Our study showed that VAN-niosome had acceptable stability during a 30-day storage time. Additionally, the VAN-niosome had stronger antibacterial and anti-biofilm properties against MRSA clinical isolates compared with free VAN. In conclusion, the result of our study demonstrated that niosomal VAN could be promising as a successful drug delivery system due to sustained drug release, negligible toxicity, and high encapsulation capacity. Also, the antibacterial and anti-biofilm studies showed the high capacity of VAN-niosome against MRSA clinical isolates. Furthermore, the results of real-time PCR exhibited that VAN-niosome could be proposed as a powerful strategy against MRSA biofilm via down-regulation of icaR gene expression.

Swab Testing to Optimize Pneumonia treatment with empiric Vancomycin (STOP-Vanc): study protocol for a randomized controlled trial.

Background: Vancomycin, an antibiotic with activity against Methicillin-resistant Staphylococcus aureus (MRSA), is frequently included in empiric treatment for community-acquired pneumonia (CAP) despite the fact that MRSA is rarely implicated in CAP. Conducting polymerase chain reaction (PCR) testing on nasal swabs to identify the presence of MRSA colonization has been proposed as an antimicrobial stewardship intervention to reduce the use of vancomycin. Observational studies have shown reductions in vancomycin use after implementation of MRSA colonization testing, and this approach has been adopted by CAP guidelines. However, the ability of this intervention to safely reduce vancomycin use has yet to be tested in a randomized controlled trial. Methods: STOP-Vanc is a pragmatic, prospective, single center, non-blinded randomized trial. Adult patients with suspicion for CAP who are receiving vancomycin and admitted to the Medical Intensive Care Unit at Vanderbilt University Medical Center will be screened for eligibility. Eligible patients will be enrolled and randomized in a 1:1 ratio to either receive MRSA nasal swab PCR testing in addition to usual care (intervention group), or usual care alone (control group). PCR testing results will be transmitted through the electronic health record to the treating clinicians. Primary providers of intervention group patients with negative swab results will also receive a page providing clinical guidance recommending discontinuation of vancomycin. The primary outcome will be vancomycin-free hours alive, defined as the number of hours alive and free of the use of vancomycin within the first seven days following trial enrollment estimated using a proportional odds ratio model. Secondary outcomes include 30-day all-cause mortality and time alive off vancomycin. Discussion: STOP-Vanc will provide the first randomized controlled trial data regarding the use of MRSA nasal swab PCR testing to guide antibiotic de-escalation. This study will provide important information regarding the effect of MRSA PCR testing and antimicrobial stewardship guidance on clinical outcomes in an intensive care unit setting. Trial registration: This trial was registered on ClinicalTrials.gov on February 22, 2024. (ClinicalTrials.gov identifier: NCT06272994).

Rose Bengal diacetate-mediated antimicrobial photodynamic inactivation: potentiation by potassium iodide and acceleration of wound healing in MRSA-infected diabetic mice.

Previous studies have shown that antimicrobial photodynamic inactivation (aPDI) can be strongly potentiated by the addition of the non-toxic inorganic salt, potassium iodide (KI). This approach was shown to apply to many different photosensitizers, including the xanthene dye Rose Bengal (RB) excited by green light (540 nm). Rose Bengal diacetate (RBDA) is a lipophilic RB derivative that is easily taken up by cells and hydrolyzed to produce an active photosensitizer. Because KI is not taken up by microbial cells, it was of interest to see if aPDI mediated by RBDA could also be potentiated by KI. The addition of 100 mM KI strongly potentiated the killing of Gram-positive methicillin-resistant Staphylocccus aureus, Gram-negative Eschericia coli, and fungal yeast Candida albicans when treated with RBDA (up to 15 µM) for 2 hours followed by green light (540 nm, 10 J/cm2). Both RBDA aPDI regimens (400 µM RBDA with or without 400 mM KI followed by 20 J/cm2 green light) accelerated the healing of MRSA-infected excisional wounds in diabetic mice, without damaging the host tissue.

A MRSA mystery: how PBP4 and cyclic-di-AMP join forces against ß-lactam antibiotics.

The high-level resistance to next-generation ß-lactams frequently found in Staphylococcus aureus isolates lacking mec, which encodes the transpeptidase PBP2a traditionally associated with methicillin-resistant Staphylococcus aureus (MRSA), has remained incompletely understood for decades. A new study by Lai et al. found that the co-occurrence of mutations in pbp4 and gdpP, which respectively cause increased PBP4-mediated cell wall crosslinking and elevated cyclic-di-AMP levels, produces synergistic ß-lactam resistance rivaling that of PBP2a-producing MRSA (L.-Y. Lai, N. Satishkumar, S. Cardozo, V. Hemmadi, et al., mBio 15:e02889-23. 2024, https://doi.org/10.1128/mbio.02889-23). The combined mutations are sufficient to explain the high-level ß-lactam resistance of some mec-lacking strains, but the mechanism of synergy remains elusive and an avenue for further research. Importantly, the authors establish that co-occurrence of these mutations leads to antibiotic therapy failure in a Caenorhabditis elegans infection model. These results underscore the need to consider this unique and novel ß-lactam resistance mechanism during the clinical diagnosis of MRSA, rather than relying on mec as a diagnostic.

Antibacterial and antibiofilm activities of zingerone and niosomal zingerone against methicillin-resistant Staphylococcus aureus (MRSA).

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Nanoparticles are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections because of the drug concentration increment at the desired location and protection from enzymatic degradation. The goal of this study was to evaluate the effect of the antibacterial and antibiofilm activities of zingerone and niosome containing zingerone against pre-formed biofilm of MRSA isolates. Materials and Methods: 62 MRSA isolates cultured from patients with diabetic ulcers were investigated. Niosomes were synthesized and characterized by X-ray diffraction, zeta potential and scanning electron microscopy (SEM). The size of niosomal particles measured by SEM and zetasizer. Results: The surface charge of prepared niosomes was about -37 mV. The effect of the zingerone and noisome containing zingerone was evaluated against biofilms of MRSA isolates. Also, the antibiofilm activity of prepared niosomes on gene expression of MRSA biofilms was evaluated using Real Time PCR. Our results demonstrated that the niosome containing zingerone had a diameter of 196.1 nm and a -37.3-mV zeta potential. Zingerone removed one and three-day old biofilms of MRSA at the concentration of 1000 µg/ml, while the zingerone-laoded niosomes removed 1, 3- and 5-days old biofilms at the concentration of 250 µg/ml, 250 µg/ml, and 500 µg/ml. Conclusion: The results indicated that niosome containing zingerone eliminated MRSA and its biofilms faster compared with free zingerone and it suggested that zingerone-encapsulated niosomes could be considered as a promising treatment against MRSA and its biofilms.

Antimicrobial Susceptibility of Various MRSA Clinical Isolates and the Impact of Glycopeptide MICs on Clinical and Microbiological Outcomes.

Objective: While vancomycin has remained the mainstay of the treatment for methicillin-resistant Staphylococcus aureus (MRSA) infections, there is growing evidence of the clinical impact of increased glycopeptide minimum inhibitory concentrations (MICs) in MRSA isolates. This study aimed to determine the susceptibility of various MRSA isolates to different antibiotics with antistaphylococcal activity and the impact of glycopeptide MICs on clinical and microbiological outcomes. Materials and Methods: This retrospective cohort study, conducted between 2013 and 2017, evaluated the susceptibility of MRSA strains isolated from various clinical samples to antistaphylococcal antibiotics using the gradient strip method. The clinical and laboratory features of patients infected with MRSA isolates with elevated glycopeptide MICs (>1 mg/L) and with isolates that had low glycopeptide MICs (≤1 mg/L) were compared. Results: A total of 104 patients infected with MRSA strains were included in this study. Male sex (odds ratio [OR]=2.48, 95% confidence interval [CI]=1.01-6.10, p=0.048), two or more comorbidities (OR=2.48, 95% CI=1.03-6.50, p=0.044), history of MRSA infection (OR=4.91, 95% CI=1.70-14.28, p=0.003) and a longer hospital stay prior to MRSA infection (OR=2.32, 95% CI=1.05-7.85, p=0.040) were independent risk factors for high glycopeptide MICs. In MRSA infections with a teicoplanin MIC of >0.75mg/L, the microbiological and treatment failures were 46.2% (p=0.044) and 60.6% (p=0.042), respectively. Conclusion: This study showed that the critical MIC value, which suggested treatment failure as well as microbiological failure in the teicoplanin-treated MRSA infections, was >0.75 mg/L rather than >1 mg/L in our study cohort. The identification of high-risk patients;for treatment failures and mortality considering gradient strip method MIC values is crucial for the effective management of MRSA infections.

Antibacterial activity of closantel against methicillin-resistant Staphylococcus aureus and itsbiofilm. / æ°¯æ°°ç¢˜æŸ³èƒºå¯¹è€ç”²æ°§è¥¿æž—é‡‘é»„è‰²è‘¡è„çƒèŒåŠå ¶ç”Ÿç‰©è†œçš„æŠ—èŒæ´»æ€§.

OBJECTIVES: The antimicrobial resistance of Staphylococcus aureus (S. aureus) has become a challenge in the treatment of infectious diseases. It is of great clinical value to discovery effective antimicrobial agents against multi-drug resistant S. aureus and its biofilms. This study aims to explore the antibacterial activity of the antiparasitic drug closantel against methicillin-resistant S. aureus and its biofilms through drug repurposing. METHODS: The sensitivity of S. aureus to closantel was assessed using microbroth dilution and disk diffusion methods. The bacteriostatic and bactericidal activities of closantel were determined by time-kill curves and colony count. Scanning electron microscopy combined with SYTOX Green and DiSC3(5) fluorescence probes were used to study the bactericidal mechanism of closantel. The influence of resistance was assessed by continuous exposure to sub-inhibitory concentrations of closantel. The anti-biofilm activity was evaluated using 96-well plates and crystal violet staining, and cytotoxicity was measured using the CCK-8 assay. RESULTS: The minimal inhibitory concentration (MIC) of closantel for both methicillin-sensitive and methicillin-resistant S. aureus ranged from 0.125 to 1.000 µg/mL. Disk diffusion tests showed that 80 µg of closantel created an inhibition zone, which increased in diameter with higher drug amounts. Sub-inhibitory concentrations (0.031 µg/mL) of closantel significantly inhibited S. aureus proliferation, reducing bacterial turbidity from 0.26±0.00 to 0.11±0.01 (t=16.06, P<0.001), with stronger inhibition at higher concentrations. Closantel at 0.25×MIC inhibited S. aureus proliferation for 12 hours, while 1×MIC inhibited it for over 24 hours, with the number of viable bacteria decreasing as the drug concentration increased. Mechanistic studies indicated that closantel effectively disrupted the integrity of S. aureus cell membranes, significantly increasing SYTOX Green and DiSC3(5) fluorescence intensity. Even after 25 days of continuous exposure to sub-inhibitory concentrations of closantel, no resistance developed. Closantel at 0.0625 µg/mL significantly inhibited biofilm formation, reducing it from 1.29±0.16 to 0.62±0.04 (t=11.62, P<0.001), showing a clear dose-dependent effect. Closantel at 2 µg/mL also significantly eradicated established biofilms, reducing biofilm mass from 1.62±0.34 to 0.51±0.39 (t=4.84, P<0.01). Additionally, closantel exhibited extremely low cytotoxicity, with half-maximal lethal concentrations for HepG2 liver cancer cells and normal LO2 liver cells both exceeding 64 µg/mL. CONCLUSIONS: Closantel exhibits strong antibacterial activity against S. aureus and its biofilm with low cytotoxicity against human cells, making it a promising candidate for new therapeutic strategies against S. aureus-related infections.

Seizing the Hidden Assassin: Current Detection Strategies for Staphylococcus aureus and Methicillin-Resistant S. aureus.

Staphylococcus aureus (S. aureus) is a kind of pathogenic bacteria which can lead to food poisoning, hospital, and community infections. S. aureus and methicillin-resistant S. aureus (MRSA) have become headaches for public health worldwide. Therefore, strengthening the detection of S. aureus and MRSA is a critical step to prevent and control its spread and infection. This review summarized multiple detection methods (electrochemical, optical, and other biosensors) for sensitive and efficient detection of nonresistant and resistant S. aureus. First, we have introduced the principle and methods of detection platform for S. aureus and MRSA. We also contrasted various detection strategies. Finally, the current situation and prospect of S. aureus and MRSA detection in the future are explored in depth, and its development direction of detection methods is also predicted. In this review, we found that although biosensors have shown tremendous brilliance in the field of monitoring, they are currently in the experimental stage. It can be certain that we are very close to entering the commercialization stage. The point-of care testing available to nonprofessionals will become a new direction. We firmly believe that the monitoring system will be more perfect and stable and public life will be healthier and safer.

Nasopharyngeal methicillin-resistant Staphylococcus aureus carriage among pilgrims at the grand Magal de Touba.

Overall prevalence of nasopharyngeal methicillin-resistant Staphylococcus aureus (MRSA) carriage in Grand Magal de Touba pilgrims was 5.2% by PCR and 2.6% acquired carriage following participation in the event. Given the potential for globalization of pathogens, surveillance is crucial to implementing timely interventions and protecting public health during the mass gathering.

Incidence of drug-resistant pathogens in community-acquired pneumonia at a safety net hospital.

The 2019 Infectious Diseases Society of America guideline for the management of community-acquired pneumonia (CAP) emphasizes the need for clinician to understand local epidemiological data to guide selection of appropriate treatment. Currently, the local distribution of causative pathogens and their associated resistance patterns in CAP is unknown. A retrospective observational study was performed of patients admitted to an 870-bed safety net hospital between March 2016 and March 2021 who received a diagnosis of CAP or healthcare-associated pneumonia within the first 48 hours of admission. The primary outcome was the incidence of CAP caused by methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PsA) as determined by comparing the number of satisfactory sputum cultures or blood cultures with these drug-resistant organisms to the total number of reviewed patients. Secondary outcomes studied included risk factors associated with CAP caused by drug-resistant organisms, utilization of broad-spectrum antibiotics, appropriate antibiotic de-escalation within 72 hours, and treatment duration. In this 220-patient cohort, MRSA or PsA was isolated from three sputum cultures and no blood cultures. The local incidence of drug-resistant pathogens among the analyzed sample of CAP patients was 1.4% (n = 3/220). The overall incidence of CAP caused by MRSA or PsA among admitted patients is low at our safety-net county hospital. Future research is needed to identify local risk factors associated with the development of CAP caused by drug-resistant pathogens.IMPORTANCEThis study investigates the incidence of drug-resistant pathogens including methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa among community-acquired pneumonia (CAP) patients at a safety net hospital. Understanding local bacteria resistance patterns when treating CAP is essential and supported by evidence-based guidelines. Our findings empower other clinicians to investigate resistance patterns at their own institutions and identify methods to improve antibiotic use. This has the potential to reduce the unnecessary use of broad-spectrum antibiotic agents and combat the development of antibiotic resistance.

Biofilm-producing ability of methicillin-resistant Staphylococcus aureus clinically isolated in China.

BACKGROUND: Staphylococcus aureus, a commensal bacterium, colonizes the skin and mucous membranes of approximately 30% of the human population. Apart from conventional resistance mechanisms, one of the pathogenic features of S. aureus is its ability to survive in a biofilm state on both biotic and abiotic surfaces. Due to this characteristic, S. aureus is a major cause of human infections, with Methicillin-Resistant Staphylococcus aureus (MRSA) being a significant contributor to both community-acquired and hospital-acquired infections. RESULTS: Analyzing non-repetitive clinical isolates of MRSA collected from seven provinces and cities in China between 2014 and 2020, it was observed that 53.2% of the MRSA isolates exhibited varying degrees of ability to produce biofilm. The biofilm positivity rate was notably high in MRSA isolates from Guangdong, Jiangxi, and Hubei. The predominant MRSA strains collected in this study were of sequence types ST59, ST5, and ST239, with the biofilm-producing capability mainly distributed among moderate and weak biofilm producers within these ST types. Notably, certain sequence types, such as ST88, exhibited a high prevalence of strong biofilm-producing strains. The study found that SCCmec IV was the predominant type among biofilm-positive MRSA, followed by SCCmec II. Comparing strains with weak and strong biofilm production capabilities, the positive rates of the sdrD and sdrE were higher in strong biofilm producers. The genetic determinants ebp, icaA, icaB, icaC, icaD, icaR, and sdrE were associated with strong biofilm production in MRSA. Additionally, biofilm-negative MRSA isolates showed higher sensitivity rates to cefalotin (94.8%), daptomycin (94.5%), mupirocin (86.5%), teicoplanin (94.5%), fusidic acid (81.0%), and dalbavancin (94.5%) compared to biofilm-positive MRSA isolates. The biofilm positivity rate was consistently above 50% in all collected specimen types. CONCLUSIONS: MRSA strains with biofilm production capability warrant increased vigilance.

Assessing the Diagnostic Performance and Clinical Utility of Nasal Methicillin Resistant Staphylococcus aureus PCR Testing in Pediatric Orbital Cellulitis.

Data are limited on the clinical impact of nasal methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) testing (nMRSA-PCR) for orbital cellulitis. This two-center, retrospective study demonstrated a negative predictive value of 98.0% and an overall lower use of anti-MRSA antibiotics, without a concomitant increase in hospital readmission.