Dysbiosis and diabetic foot ulcers: A metabolic perspective of Staphylococcus aureus infection.

Staphylococcus aureus (S. aureus) infection is the most prevalent and resistant bacterial infection, posing a worldwide health risk. Compared with healthy people, diabetes patients with weak immune function and abnormal metabolism are more vulnerable to bacterial infection, which aggravates the intensity of infection and causes a series of common and dangerous complications, such as diabetes foot ulcer (DFU). Due to metabolic abnormalities of diabetic patients, S. aureus on the skin surface of DFU transitions from a commensal to an invasive infection. During this process, S. aureus resists a series of unfavorable conditions for bacterial growth by altering energy utilization and metabolic patterns, and secretes various virulence factors, causing persistent infection. With the emergence of multiple super-resistant bacteria, antibiotic treatment is no longer the only treatment option, and developing new drugs and therapies is urgent. Regulating the metabolic signaling pathway of S. aureus plays a decisive role in regulating its virulence factors and impacts adjuvant therapy for DFU. This article focuses on studying the impact of regulating metabolic signals on the virulence of S. aureus from a metabolism perspective. It provides an outlook on the future direction of the novel development of antimicrobial therapy.

Characterization of a membrane toxin-antitoxin system, tsaAT, from Staphylococcus aureus.

Bacterial toxin-antitoxin (TA) systems consist of a toxin that inhibits essential cellular processes, such as DNA replication, transcription, translation, or ATP synthesis, and an antitoxin neutralizing their cognate toxin. These systems have roles in programmed cell death, defense against phage, and the formation of persister cells. Here, we characterized the previously identified Staphylococcus aureus TA system, tsaAT, which consists of two putative membrane proteins: TsaT and TsaA. Expression of the TsaT toxin caused cell death and disrupted membrane integrity, whereas TsaA did not show any toxicity and neutralized the toxicity of TsaT. Furthermore, subcellular fractionation analysis demonstrated that both TsaA and TsaT localized to the cytoplasmic membrane of S. aureus expressing either or both 3xFLAG-tagged TsaA and 3xFLAG-tagged TsaT. Taken together, these results demonstrate that the TsaAT TA system consists of two membrane proteins, TsaA and TsaT, where TsaT disrupts membrane integrity, ultimately leading to cell death. Although sequence analyses showed that the tsaA and tsaT genes were conserved among Staphylococcus species, amino acid substitutions between TsaT orthologs highlighted the critical role of the 6th residue for its toxicity. Further amino acid substitutions indicated that the glutamic acid residue at position 63 in the TsaA antitoxin and the cluster of five lysine residues in the TsaT toxin are involved in TsaA's neutralization reaction. This study is the first to describe a bacterial TA system wherein both toxin and antitoxin are membrane proteins. These findings contribute to our understanding of S. aureus TA systems and, more generally, give new insight into highly diverse bacterial TA systems.

Advanced Electrochemical Biosensing toward Staphylococcus aureus Based on the RPA-CRISPR/Cas12a System and Conductive Nanocomposite.

Staphylococcus aureus (S. aureus) is a prevalent foodborne pathogen that poses significant challenges to food safety. Herein, a sensitive and specific electrochemical biosensor based on RPA-CRISPR/Cas12a is developed for evaluating S. aureus. In the presence of S. aureus, the extracted target DNA fragments are efficiently amplified by recombinase polymerase amplification (RPA). The designed crRNA, binding to Cas12a, effectively recognizes the target fragment cleaving hpDNA. The signal molecule of hpDNA is cleaved from the sensing interface, resulting in a reduction of current response. Under optimal experimental conditions, the developed electrochemical biosensor exhibits remarkable sensitivity in detecting S. aureus. The linear range for quantifying S. aureus in pure culture is 1.04 × 101-1.04 × 108 CFU/mL, with a detection limit as low as 3 CFU/mL. In addition, the biosensor enables the accurate and sensitive detection of S. aureus in milk within a linear range of 1.07 × 101-1.07 × 107 CFU/mL. The electrochemical biosensor enhances anti-interference capability owing to the specific amplification of RPA primers and the single-base recognition ability of crRNA. The RPA-CRISPR/Cas12a biosensor exhibits exceptional anti-interference capability, precision, and sensitivity, thereby establishing a robust foundation for real-time monitoring of microbial contamination.

Nanocomposites: silver nanoparticles and bacteriocins obtained from lactic acid bacteria against multidrug-resistant Escherichia coli and Staphylococcus aureus.

Drug-resistant bacteria such as Escherichia coli and Staphylococcus aureus represent a global health problem that requires priority attention. Due to the current situation, there is an urgent need to develop new, more effective and safe antimicrobial agents. Biotechnological approaches can provide a possible alternative control through the production of new generation antimicrobial agents, such as silver nanoparticles (AgNPs) and bacteriocins. AgNPs stand out for their antimicrobial potential by employing several mechanisms of action that can act simultaneously on the target cell such as the production of reactive oxygen species and cell wall rupture. On the other hand, bacteriocins are natural peptides synthesized ribosomally that have antimicrobial activity and are produced, among others, by lactic acid bacteria (LAB), whose main mechanism of action is to produce pores at the level of the cell membrane of bacterial cells. However, these agents have disadvantages. Nanoparticles also have limitations such as the tendency to form aggregates, which decreases their antibacterial activity and possible cytotoxic effects, and bacteriocins have a narrow spectrum of action, require high doses to be effective, and can be degraded by proteases. Given these limitations, nanoconjugates of these two agents have been developed that can act synergistically in the control of pathogenic bacteria resistant to antibiotics. This review focuses on knowing relevant aspects of the antibiotic resistance of E. coli and S. aureus, the characteristics of these new generation antibacterial agents, and their effect alone or forming nanoconjugates that are more effective against the multiresistant mentioned bacteria.

Brodie's Abscess of the Ankle Presenting as a Tumor: A Summary of Five Cases.

Introduction: A Brodie's abscess is a form of subacute osteomyelitis that is often considered in the differential diagnosis of other benign and malignant bone lesions. The authors summarize the findings of five cases of Brodie's abscesses in the distal tibia initially thought to be tumors by the referring physicians. Case Report: All five cases were presented to the referring physicians with a chief complaint of ankle pain. All patients complained of chronic ankle pain and swelling that was aggravated by activity without constitutional symptoms. On physical examination, all patients presented with point tenderness over the distal tibia/malleolar regions. Three out of the five cases had a full range of ankle motion; the other two had limited dorsiflexion secondary to pain. All inflammatory laboratory values were within normal limits or only slightly elevated. All initial radiographs of the cases described demonstrated a well-defined radiolucent lesion within the distal tibia. In all cases, patients were treated with curetting, with or without bone graft. Bacterial and fungal cultures were negative in all five patients and no long-term post-operative antibiotics were administered. Conclusion: In this report, we discuss the clinical, radiographic, and pathologic features of this relatively rare condition in the distal tibia. The distinct clinicopathologic features of the disease process are presented to distinguish Brodie's abscess from a bone tumor.

Staphylococcus aureus colonizing the skin microbiota of adults with severe atopic dermatitis exhibits genomic diversity and convergence in biofilm traits.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder exacerbated by Staphylococcus aureus colonization. The specific factors that drive S. aureus overgrowth and persistence in AD remain poorly understood. This study analyzed skin barrier functions and microbiome diversity in lesional (LE) and non-lesional (NL) forearm sites of individuals with severe AD compared to healthy control subjects (HS). Notable differences were found in transepidermal water loss, stratum corneum hydration, and microbiome composition. Cutibacterium was more prevalent in HS, while S. aureus and S. lugdunensis were predominantly found in AD LE skin. The results highlighted that microbial balance depends on inter-species competition. Specifically, network analysis at the genus level demonstrated that overall bacterial correlations were higher in HS, indicating a more stable microbial community. Notably, network analysis at the species level revealed that S. aureus engaged in competitive interactions in NL and LE but not in HS. Whole-genome sequencing (WGS) showed considerable genetic diversity among S. aureus strains from AD. Despite this variability, the isolates exhibited convergence in key phenotypic traits such as adhesion and biofilm formation, which are crucial for microbial persistence. These common phenotypes suggest an adaptive evolution, driven by competition in the AD skin microenvironment, of S. aureus and underscoring the interplay between genetic diversity and phenotypic convergence in microbial adaptation.

Acne-related UVA-induced facial fluorescence: An exploratory study from physiological properties to tissue structure information.

UVA-induced facial fluorescence (UVAF) is recognized as an objective measurement technique to quantify the severity of acne. However, notable inconsistencies in quantitative outcomes have been observed in various studies, possibly due to the fact that different colors of fluorescence represent different pathophysiological implications. This study investigated the pathophysiological importance of UVAF color differences and improved its reliability in assessing acne severity. MIDOO Smart Skin Imager was used to capture UVAF and analyze the correlation between fluorescence colors and acne lesions. Techniques such as two-photon excited fluorescence microscopy, scanning electron microscopy, western blot, and high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) were used to examine the biochemical composition and structure of comedonal plugs and follicular casts associated with different fluorescence colors. We found that green fluorescence correlates with non-inflammatory acne lesions (comedones), while orange-red fluorescence shows no correlation with either type of lesion. Green fluorescence is associated with higher levels of keratin, indicating keratinization, while orange-red fluorescence is associated with porphyrin from S. epidermidis. UVAF color differences - orange-red are from porphyrins and green from keratin. This distinction helps to understand the structural and physiological bases of facial fluorescence, with potential implications for clinical evaluations of acne.

Sinonasal Squamous Cell Carcinoma Mimicking a Brain Abscess: Report of a Unique Case.

Sinonasal cancers are rare tumors with squamous cell carcinoma (SCC) being one of the more common histological subtypes. These carcinomas typically invade the sinus cavity from which they originate, progressively eroding surrounding bony structures and extending to adjacent anatomical regions. In rare instances, they may breach the posterior or superior walls to invade the anterior cranial fossa (ACF) and frontal lobes. The normal flora of the nasal cavity and paranasal sinuses includes Staphylococcus aureus, Staphylococcus epidermidis, α- and γ-streptococci, Propionibacterium acnes, and aerobic diphtheroids. To our knowledge, cases of sinonasal malignancies extending into the frontal sinus and ACF, leading to a frontal lobe abscess caused by these organisms, have not been well-documented. We present a case of a 36-year-old male who underwent surgery for a right frontal brain abscess caused by Staphylococcus aureus. Histopathological analysis of the abscess wall revealed moderately differentiated SCC arising from the paranasal sinuses, highlighting a rare and intriguing presentation of this disease.

Prevalence of Bacteremia and Antimicrobial Resistance Pattern Among Patients in South Lebanon.

BACKGROUND: Bacteremia are a leading cause of morbidity and mortality worldwide. Rising prevalence and antimicrobial resistance (AMR) are critical public health issues. This study aims to determine the prevalence of bacteremia and the antimicrobial resistance pattern among patients in South Lebanon. METHODS: A cross-sectional study analyzed 76 positive blood cultures from Hammoud and Labib Hospitals in South Lebanon between September 2023 and March 2024.The phenotype and antimicrobial susceptibility of gram-positive and gram-negative was determined by using disk diffusion. Genotypically, PCR was used to detect the carbapenemase-resistant Enterobacterales (CRE), extended-spectrum ß-lactamases (ESBL) and Methicillin Resistant Staphylococcus aureus (MRSA) genes. RESULTS: Out of 76 isolates, 38(50%) were gram-positive and 38(50%) were gram-negative. Escherichia coli was the most common among gram-negative (18. 42%), with 10.52% ESBL and 3.94% CRE. Staphylococcus coagulase negative was the most common among gram-positive (40.78%), followed by S. aureus (6.57%), with 3.94% MRSA.The prevalent ESBL gene was CTX-M (100%), and for the CRE, NDM (66.66%). Regarding S. aureus, (66.66%) were mecA. DISCUSSION: The diverse bacteremia isolates and resistance genes in South Lebanon reflect global variability in incidence and resistance profiles. CONCLUSION: High rates of bacteremia and AMR in South Lebanon underscore the need for effective antibiotic stewardship programs.

Impact of acidic and alkaline conditions on Staphylococcus aureus and Acinetobacter baumannii interactions and their biofilms.

Bacterial biofilms pose significant challenges due to their association with antibiotic resistance, metabolic adaptation, and survival under harsh conditions. Among notable pathogens forming biofilms, Staphylococcus aureus and Acinetobacter baumannii are concerning pathogens in nosocomial settings. However, their behaviour under acidic (pH 4.5) and alkaline (pH10.5) conditions, especially in co-culture setups, remains insufficiently understood. This study investigates these aspects, by examining growth rates, biofilm formation, pH shifts, phenotypic analysis, and gene expression profiles. The results showed A. baumannii exhibited reduced  growth and biofilm formation at pH 4.5, while S. aureus showed slow growth and low biofilm formation at pH10.5 in mono-cultures. S. aureus leaned towards an acidic pH (6-6.5), whereas A. baumannii shifted towards an alkaline pH (8-9). In co-culture environments, growth rates and biofilm formation increased across all pH conditions, converging towards a neutral pH over time. Phenotypic motility assays indicated that A. baumannii exhibited greater motility in alkaline conditions, while S. aureus showed increased staphyloxanthin production under acidic conditions. Gene expression analyses revealed that the fibronectin-binding protein A (FnbA) and N-acetylglucosaminyl-transferase (icaA) genes, responsible for initial attachment during biofilm formation, were highly expressed in acidic co-culture condition but poorly expressed in alkaline condition. In A. baumannii, the outer membrane protein A (OmpA) gene associated with adhesion and virulence, was upregulated in co-culture. The LuxR gene involved in quorum sensing was upregulated in acidic conditions and poorly expressed at pH 10.5. This study elucidates the metabolic adaptability and biofilm formation tendencies of S. aureus towards acidic conditions and A. baumannii towards alkaline conditions, providing insights for better management of biofilm-related infections.

Bactericidal and anti-quorum sensing activity of repurposing drug visomitin against staphylococcus aureus.

With the growing antibiotic resistance in Staphylococcus aureus, it is imperative to develop innovative therapeutic strategies against new targets to reduce selective survival pressures and incidence of resistance. In S. aureus, interbacterial communication relies on a quorum sensing system that regulates gene expression and physiological activities. Here, we identified that Visomitin, an antioxidant small molecule, exhibited bactericidal efficacy against methicillin-resistant S. aureus and its high tolerance phenotypes like intracellular bacteria and persister cells without inducing resistance. Critically, sub-minimal inhibitory concentrations (sub-MICs) of Visomitin could serve as a potent quorum-quencher reducing virulence production (such as haemolysin and staphyloxanthin), along with inhibiting biofilm formation, self-aggregation, and colony spreading of S. aureus. These effects were probably mediated by interfering with the S. aureus accessory gene regulator quorum sensing system. In summary, our findings suggest that Visomitin shows dual antimicrobial effects, including bactericidal effects at the concentrations above MIC and quorum sensing inhibition effects at sub-MICs, which holds promise for treating MRSA-related refractory infections.

Intraspecific cooperation allows the survival of Staphylococcus aureus staff: a novel strategy for disease relapse.

BACKGROUND: The contribution of interspecies interactions between coinfecting pathogens to chronic refractory infection by affecting pathogenicity is well established. However, little is known about the impact of intraspecific interactions on infection relapse, despite the cross-talk of different strains within one species is more common in clinical infection. We reported a case of chronic refractory pulmonary infection relapse, caused by two methicillin-sensitive S. aureus (MSSA) strains (SA01 and SA02) and revealed a novel strategy for relapse via intraspecific cooperation. METHODS: The hemolytic ability, growth curve, biofilm formation, virulence genes and response of G. mellonella larvae to S. aureus infection were analysed to confirm this hypothesis. RESULTS: SA02 hemolytic activity was inhibited by SA01, along with the expression of hemolysin genes and the virulence factor Hla. Additionally, SA01 significantly enhanced the biofilm formation of SA02. AIP-RNAIII may be a possible pathway for this interaction. Compared with mono-infection, a worse outcome (decreased larval survival and increased microbial burden) of the two MSSA strains coinfected with G. mellonella confirmed that intraspecific interactions indeed enhanced bacterial survival in vivo. CONCLUSION: The intraspecific interaction of S. aureus could lead to chronic refractory infection via pathogenicity changes.

Dermoscopic Features of Dermatitis Cruris Pustulosa et Atrophicans: A Retrospective Study from a Tertiary Care Center in South India.

Background: Dermatitis cruris pustulosa et atrophicans (DCPA) is a chronic superficial folliculitis that can cause scarring alopecia if left untreated. Hardly any studies are there describing the dermoscopic features of DCPA. Dermoscopy can be a useful tool for diagnosing DCPA in addition to clinical and histopathological features and for differentiating other conditions like superficial folliculitis, folliculitis decalvans, and pseudofolliculitis. Aims/Objectives: The aim of this retrospective study was to describe the dermoscopic features of 30 patients with DCPA at a tertiary care center in South India. Materials and Methods: A retrospective study of clinical and biopsy-proven cases of DCPA at a tertiary care center in South India. Results: Thirty patients of DCPA of skin phototype IV or V were studied. Male preponderance of DCPA was noted in our study. Lower extremities 28 (93.3%) and upper extremities 2 (6.7%) were the common sites of involvement. The most common findings noted in dermoscopy were follicular-based pustules in 30 (100%) patients, follicular white structureless area in 16 (53.3%), perifollicular collarette of scales in 12 (40%), diffuse background dotted blood vessels in 12 (40%), and the absence of follicular orifices in 12 (40%). Other findings were yellow or hemorrhagic scales, perifollicular linear white lines, broken hair, and perifollicular dotted blood vessels. Pigmentary patterns observed were dark brown pigmentation, blue-grey globules, blue-grey dots, and accentuation of the pigmentary network. Limitations: The limitations of the study were the retrospective nature of the study, the small sample size, and the lack of a comparison group. Conclusion: The predominant dermoscopic features observed in our patients were follicular-based pustules, follicular white structureless areas, perifollicular collarette of scales, diffuse background dotted blood vessels, and the absence of follicular orifices. Vascular and pigmentary patterns were less commonly noted.

Staphylococcus aureus SOS response: Activation, impact, and drug targets.

Staphylococcus aureus is a common cause of diverse infections, ranging from superficial to invasive, affecting both humans and animals. The widespread use of antibiotics in clinical treatments has led to the emergence of antibiotic-resistant strains and small colony variants. This surge presents a significant challenge in eliminating infections and undermines the efficacy of available treatments. The bacterial Save Our Souls (SOS) response, triggered by genotoxic stressors, encompasses host immune defenses and antibiotics, playing a crucial role in bacterial survival, invasiveness, virulence, and drug resistance. Accumulating evidence underscores the pivotal role of the SOS response system in the pathogenicity of S. aureus. Inhibiting this system offers a promising approach for effective bactericidal treatments and curbing the evolution of antimicrobial resistance. Here, we provide a comprehensive review of the activation, impact, and key proteins associated with the SOS response in S. aureus. Additionally, perspectives on therapeutic strategies targeting the SOS response for S. aureus, both individually and in combination with traditional antibiotics are proposed.

Comparative Evaluation of the Antibiotic Resistance Profile of Staphylococcus aureus Isolated From Breeders and Livestock.

Objectives: Animals are a potential source of Methicillin Resistant Staphylococcus aureus. This study evaluated the antibiotics susceptibility pattern of S. aureus isolates from breeders and livestock. Methods: S. aureus strains were isolated from 180 livestock and 48 livestock farmers and identified using standard methods. Antibiotic susceptibility profiles and MRSA status were determined via disk diffusion susceptibility method. Results: Among farm workers, 37.5% were colonized by S. aureus, with pig farm workers exhibiting the highest prevalence (56.2%), cattle herders (37.5%), and goat farm workers (18.7%). MRSA carriage among livestock isolates was 41.3%, while, six isolates from the poultry farm worker were MRSA, representing a carriage of 33.3%. Drug susceptibility profiles revealed differential patterns between isolates from breeders and animals. Gentamicin and levofloxacin demonstrated higher efficacy against farm worker isolates compared to animal isolates. Resistance to cefuroxime was higher among animal isolates (84.1%) as against the 66.7% for the breeders. Conclusion: The identification of multidrug-resistant S. aureus strains underscores the risk posed to humans in contact with animals. These findings stress the importance of monitoring and managing MRSA transmission between animals and humans.

Two novel plasmids harboring the multiresistance gene cfr in porcine Staphylococcus equorum.

BACKGROUND: The emergence and transmission of the multidrug resistance gene cfr have raised public health concerns worldwide. OBJECTIVES: Multidrug-resistant Staphylococcus equorum isolates can pose a threat to public health. In this study, we have characterised the whole-genome of one Staphylococcus equorum isolate harboring two distinct cfr-carrying plasmids. METHODS: Antimicrobial susceptibility testing was performed by broth microdilution. Genomic DNA was sequenced using both the Illumina HiSeq X Ten and Nanopore MinION platforms. De novo hybrid assembly was performed by Unicycler. Genomic data were assessed by in silico prediction and bioinformatic tools. RESULTS: Staphylococcus equorum isolate SN42 exhibited resistance or high MICs to linezolid, erythromycin, tetracycline, oxacillin, clindamycin, virginiamycin, tiamulin, chloramphenicol and florfenicol. It carried two cfr-harboring plasmids: the RepA N-family plasmid pSN42-51K and the Inc18-family plasmid pSN42-50K. These two plasmids exhibited low structural similarities to the so far reported cfr-carrying plasmids. Both plasmids harbored an arsenic resistance operon, copper and cadmium resistance genes as well as the lincosamide-pleuromutilin-streptogramin A resistance gene lsa(B). In addition, plasmid pSN42-51K carried two erm(B) genes for macrolide-lincosamide-streptogramin B resistance, the streptomycin resistance gene ant(6)-Ia as well as mercury resistance genes while pSN42-50K was associated with the heavy metal translocating P-type ATPase gene hmtp. The co-carriage and co-existence of these antimicrobial resistance and heavy metal resistance genes increases the likelihood of co-selection of the cfr-carrying plasmids. CONCLUSION: This is the first report of S. equorum carrying two distinct cfr-carrying plasmids, underscoring the need for ongoing surveillance to address the potential dissemination of multi-drug resistance in bacteria from food-producing animals to ensure food safety and public health.

Presence of multiple van genes among glycopeptide non-susceptible Staphylococcus aureus exhibiting in vitro MIC creep phenomenon: A study from north-east India.

Background & objectives The global prevalence of vancomycin-resistant Staphylococcus aureus (VRSA) has increased two fold since 2010, accounting for 2.4 per cent of S. aureus infections. The emerging hVISA isolates and their increasing trends pose a serious therapeutic challenge. The present study investigated in vitro vancomycin and teicoplanin minimum inhibitory concentration (MIC) creep in S. aureus and assessed their revertants. Methods A total of 845 isolates were collected for this study, and 246 were confirmed as S. aureus. Molecular characterization of vancomycin resistance was carried out by PCR assay targeting genes types viz: vanA, vanB, vanC, vanC2/C3, vanD, vanE, and vanG. MIC was determined for vancomycin and teicoplanin by agar dilution method. MIC creep and revertant analysis were done by broth dilution method in the presence and absence of antibiotics. Results PCR assay confirmed 12 isolates were harboured vanA, followed by vanD (n=8) and vanB (n=7). The study showed 69 isolates were screened positive for glycopeptide non-susceptibility. While analyzing vancomycin MIC creep, four isolates showed a significant increase in MIC, whereas no creep phenomenon was observed for the rest. In the case of teicoplanin, seven isolates showed the MIC creep phenomenon. Revertant analysis of all the isolates that showed MIC creep phenomenon for vancomycin and teicoplanin reverted to their original MIC when the antibiotic pressure was withdrawn. Interpretation & conclusions In the present study setting, glycopeptide non-susceptibility was found in eight per cent of the isolates, and the present study found the occurrence of multiple van genes from isolates calculated from a single study center will impose a serious challenge in infection control and antibiotic policy. This study also underscores that heterogenic resistant isolates, upon exposure to vancomycin and teicoplanin at a minimum level, exhibited an increase in MIC, which will impact individuals receiving glycopeptide therapy.

The roles of cell wall inhibition responsive protein CwrA in the pathogenicity of Staphylococcus aureus.

The ability to form robust biofilms and secrete a diverse array of virulence factors are key pathogenic determinants of Staphylococcus aureus, causing a wide range of infectious diseases. Here, we characterized cwrA as a VraR-regulated gene encoding a cell wall inhibition-responsive protein (CwrA) using electrophoretic mobility shift assays. We constructed cwrA deletion mutants in the genetic background of methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains. Phenotypic analyses indicated that deletion of cwrA led to impaired biofilm formation, which was correlated with polysaccharide intercellular adhesin (PIA). Besides, the results of real-time quantitative PCR (RT-qPCR) and ß-galactosidase activity assay revealed that CwrA promoted biofilm formation by influence the ica operon activity in S. aureus. Furthermore, cwrA deletion mutants released less extracellular DNA (eDNA) in the biofilm because of their reduced autolytic activity compared to the wild-type (WT) strains. We also found that cwrA deletion mutant more virulence than the parental strain because of its enhanced hemolytic activity. Mechanistically, this phenotypic alteration is related to activation of the SaeRS two-component system, which positively regulates the transcriptional levels of genes encoding membrane-damaging toxins. Overall, our results suggest that CwrA plays an important role in modulating biofilm formation and hemolytic activity in S. aureus.

WGS Analysis of Staphylococcus warneri Outbreak in a Neonatal Intensive Care Unit.

Purpose: Staphylococcus warneri is an opportunistic pathogen responsible for hospital-acquired infections (HAIs). The aim of this study was to describe an outbreak caused by S. warneri infection in a neonatal intensive care unit (NICU) and provide investigation, prevention and control strategies for this outbreak. Methods: We conducted an epidemiological investigation of the NICU S. warneri outbreak, involving seven neonates, staff, and environmental screening, to identify the source of infection. WGS analyses were performed on S. warneri isolates, including species identification, core genome single-nucleotide polymorphism (cgSNP) analysis, pan-genome analysis, and genetic characterization assessment of the prevalence of specific antibiotic resistance and virulence genes. Results: Eight S. warneri strains were isolated from this outbreak, with seven from neonates and one from environment. Six clinical cases within three days in 2021 were linked to one strain isolated from environmental samples; isolates varied by 0-69 SNPs and were confirmed to be from an outbreak through WGS. Multiple infection prevention measures were implemented, including comprehensive environmental disinfection and stringent protocols, and all affected neonates were transferred to the isolation wards. Following these interventions, no further cases of S. warneri infections were observed. Furthermore, pan-genome analysis results suggested that in human S. warneri may exhibit host specificity. Conclusion: The investigation has revealed that the outbreak was linked to the milk preparation workbench by the WGS. It is recommended that there be a stronger focus on environmental disinfection management in order to raise awareness, improve identification, and prevention of healthcare-associated infections that are associated with the hospital environment.

Antibacterial and antioxidant properties of sumac extract on methicillin-resistant Staphylococcus aureus.

The research aimed to evaluate the antioxidative and antibacterial characteristics of aqueous sumac extract on methicillin-resistant Staphylococcus aureus through in-vitro and in-vivo study. Sumac extract has been obtained through the soaking method, and its antioxidant properties were gauged using the DPPH free radical scavenging method. The minimum inhibitory concentration (MIC) of sumac extract was determined on S. aureus obtained from hospitalized patients, as well as an assessment of biofilm-formation and the release of bacterial intracellular compounds. in vivo experimentation involved injecting bacteria (108 cfu/ml) into mice, which subsequently manifested indicators of symptoms of infection, and the number of bacteria within their bloodstream was quantified. The Sumac extract demonstrated strong antioxidant properties at concentrations of 1000 mg/ml. Furthermore, the agar tests for the gram staining, mannitol, coagulase, and DNase revealed that 190 cultured bacteria samples were identified as Staphylococcus aureus. These bacteria were resistant to clindamycin, ciprofloxacin, and methicillin antibiotics, but sensitive to erythromycin and penicillin antibiotics. Additionally, the bacteria displayed significant methicillin resistance and formed a strong biofilm (65.78%). The sumac extract showed a MIC range of 125-1000 µg/ml against Staphylococcus aureus. Treatment with concentrations above the MIC was found to prevent the formation of biofilm and increase the release of bacterial intracellular compounds. Sumac extract led to a decrease in bacterial count in the blood of mice and reduced signs of infection. Sumac extract demonstrated powerful antioxidant and antibacterial effects against resistant microorganisms, suggesting its potential as a promising compound for the treatment of resistant infections in future research.