Staphylococcus Aureus
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Andrew J.T. Muir ◽  
Andrew J. Niehaus ◽  
Joseph W. Lozier ◽  
Sara L. Cole ◽  
Zarah A. Belacic ◽  

Abstract OBJECTIVE To investigate the chondroprotective effects of autologous platelet-rich plasma (PRP), ampicillin-sulbactam (AmpS), or PRP combined with AmpS (PRP+AmpS) in an in vitro chondrocyte explant model of bovine Staphylococcus aureus–induced septic arthritis. SAMPLE Autologous PRP and cartilage explants obtained from 6 healthy, adult, nonlactating Jersey-crossbred cows. ProcedureS Autologous PRP was prepared prior to euthanasia using an optimized double centrifugation protocol. Cartilage explants collected from grossly normal stifle joints were incubated in synovial fluid (SF) alone, S aureus–inoculated SF (SA), or SA supplemented with PRP (25% culture medium volume), AmpS (2 mg/mL), or both PRP (25% culture medium volume) and AmpS (2 mg/mL; PRP+AmpS) for 24 hours. The metabolic activity, percentage of dead cells, and glycosaminoglycan content of cartilage explants were measured with a resazurin-based assay, live-dead cell staining, and dimethylmethylene blue assay, respectively. Treatment effects were assessed relative to the findings for cartilage explants incubated in SF alone. RESULTS Application of PRP, AmpS, and PRP+AmpS treatments significantly reduced S aureus–induced chondrocyte death (ie, increased metabolic activity and cell viability staining) in cartilage explants, compared with untreated controls. There were no significant differences in chondrocyte death among explants treated with PRP, AmpS, or PRP+AmpS. CLINICAL RELEVANCE In this in vitro explant model of S aureus–induced septic arthritis, PRP, AmpS, and PRP+AmpS treatments mitigated chondrocyte death. Additional work to confirm the efficacy of PRP with bacteria commonly associated with clinical septic arthritis in cattle as well as in vivo evaluation is warranted.

2021 ◽  
Erika Reategui Schwarz ◽  
Adriana van de Guchte ◽  
Amy C. Dupper ◽  
Ana Berbel Caban ◽  
Devika Nadkarni ◽  

Abstract Background. Healthcare-associated infections pose a potentially fatal threat to patients worldwide and Staphylococcus aureus is one of the most common causes of healthcare-associated infections. S. aureus is a common commensal pathogen and a frequent cause of bacteremia, with studies demonstrating that nasal and blood isolates from single patients match more than 80% of the time. Here we report on a contemporary collection of colonizing isolates from those with methicillin-resistant S. aureus (MRSA) bloodstream infections to evaluate the diversity within hosts, and detail the clinical features associated with concomitant nasal colonization.Methods. Swabs of the bilateral anterior nares were obtained from patients diagnosed with MRSA bacteremia. A single colony culture from the blood and an average of 6 colonies from the nares were evaluated for MRSA growth. For the nares cultures, we typed multiple isolates for staphylococcal protein A (spa) and derived the clonal complexes. Demographic and clinical data were obtained retrospectively from the electronic medical record system and analysed using univariate and multivariable regression models.Results. Over an 11-month period, 68 patients were diagnosed with MRSA bloodstream infection, 53 were swabbed, and 37 (70%) were colonized with MRSA in the anterior nares. We performed molecular typing on 210 nasal colonies. Spa types and clonal complexes found in the blood were also detected in the nares in 95% of the cases. We also found that 11% of patients carried more than one clone of MRSA in the nares. Male sex and history of prior hospitalization within the past 90 days increased odds for MRSA colonization. Conclusion. The molecular epidemiological landscape of colonization in the setting of invasive disease is diverse and defining the interplay between colonization and invasive disease is critical to combating invasive MRSA disease.

2021 ◽  
Marloes Machilia Adriana Roosevelt van Dorst ◽  
Shohreh Azimi ◽  
Sitti Wahyuni ◽  
Aldian Irma Amarrudin ◽  
Erliyani Sartono ◽  

BACKGROUND: Nasopharyngeal carriage of pathogenic bacteria precedes invasive disease and higher rates are found in low socioeconomic-status (SES) settings. Local immune responses are important for controlling colonization, but whether SES affects these responses is currently unknown. OBJECTIVE: Examining bacterial colonization and cytokine response in nasal mucosa of children from high and low SES. METHODS: Twenty-five cytokines were measured in nasal fluid. qPCR was performed to determine carriage and density of Haemophilus influenzae (H. influenzae), Streptococcus pneumoniae (S. pneumoniae), Moraxella catarrhalis (M. catarrhalis) and Staphylococcus aureus (S. aureus). RESULTS: The densities of H. influenzae and S. pneumoniae were increased in low compared to the high SES (p=0.006, p=0.026), with respectively 6 and 67 times higher median densities. Densities of H. influenzae and S. pneumoniae were positively associated with levels of IL-1beta (p=0.002, p=0.008) and IL-6 (p<0.001, p=0.006). After correcting for bacterial density, IL-6 levels were increased in colonized children from high compared to low SES for both H. influenzae and S. pneumoniae (both p=0.039). CONCLUSION: Increased density of H. influenzae and S. pneumoniae was observed in low SES children, while IL-6 levels associated with colonization were reduced in these children, indicating that immune responses to bacterial colonization were altered by SES.

BioFactors ◽  
2021 ◽  
Yu Chen ◽  
Jing Yang ◽  
Zhi Huang ◽  
Hongyuan Jing ◽  
Baoyi Yin ◽  

3 Biotech ◽  
2021 ◽  
Vol 12 (1) ◽  
Adhita Sri Prabakusuma ◽  
Jingjing Zhu ◽  
Yanan Shi ◽  
Qingwen Ma ◽  
Qiong Zhao ◽  

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Meera Maharjan ◽  
Anil Kumar Sah ◽  
Susil Pyakurel ◽  
Sabita Thapa ◽  
Susan Maharjan ◽  

Staphylococcus aureus, a commensal on the skin and in the nasal cavity of humans, is one of the most serious cases of nosocomial infections. Moreover, methicillin-resistant S. aureus (MRSA) is a leading cause of morbidity and mortality worldwide. For the treatment of MRSA infections, vancomycin is considered as a drug of choice. However, the emergence of vancomycin resistance among MRSA isolates has been perceived as a formidable threat in therapeutic management. To estimate the rate of vancomycin-resistant S. aureus (VRSA) and to detect the vancomycin-resistant genes, namely, vanA and vanB, among the isolates, a hospital-based cross-sectional study was conducted from July to December 2018 in Annapurna Neurological Institute and Allied Science, Kathmandu, Nepal. S. aureus was isolated and identified from different clinical samples and processed for antibiotic susceptibility testing by the modified Kirby–Bauer disc diffusion method. The screening of MRSA was performed as per Clinical and Laboratory Standard Institute (CLSI) guidelines. VRSA was confirmed by the minimum inhibitory concentration (MIC) method by employing E-test strips. All the phenotypically confirmed VRSA were further processed to detect the vanA and vanB gene by using the conventional polymerase chain reaction (PCR) method. A total of 74 (20.3%) S. aureus were isolated, and the highest percentage of S. aureus was from the wound samples (36.5%). Of 74 S. aureus isolates, the highest number (89.2%) was resistant to penicillin, and on the other hand, linezolid was found to be an effective drug. Likewise, 45 (60.81%) were found to be MRSA, five (11.11%) were VRSA, and 93.2% of S. aureus isolates showed an MAR index greater than 0.2. Two VRSA isolates (40%) were positive for the vanA gene. The higher prevalence of MRSA and significant rate of VRSA in this study recommend routine surveillance for the MRSA and VRSA in hospital settings before empirical therapy.

2021 ◽  
Vol 12 ◽  
Francesca Berini ◽  
Viviana Teresa Orlandi ◽  
Federica Gamberoni ◽  
Eleonora Martegani ◽  
Ilaria Armenia ◽  

In the era of antimicrobial resistance, the use of nanoconjugated antibiotics is regarded as a promising approach for preventing and fighting infections caused by resistant bacteria, including those exacerbated by the formation of difficult-to-treat bacterial biofilms. Thanks to their biocompatibility and magnetic properties, iron oxide nanoparticles (IONPs) are particularly attractive as antibiotic carriers for the targeting therapy. IONPs can direct conjugated antibiotics to infection sites by the use of an external magnet, facilitating tissue penetration and disturbing biofilm formation. As a consequence of antibiotic localization, a decrease in its administration dosage might be possible, reducing the side effects to non-targeted organs and the risk of antibiotic resistance spread in the commensal microbiota. Here, we prepared nanoformulations of the ‘last-resort’ glycopeptides teicoplanin and vancomycin by conjugating them to IONPs via surface functionalization with (3-aminopropyl) triethoxysilane (APTES). These superparamagnetic NP-TEICO and NP-VANCO were chemically stable and NP-TEICO (better than NP-VANCO) conserved the typical spectrum of antimicrobial activity of glycopeptide antibiotics, being effective against a panel of staphylococci and enterococci, including clinical isolates and resistant strains. By a combination of different methodological approaches, we proved that NP-TEICO and, although to a lesser extent, NP-VANCO were effective in reducing biofilm formation by three methicillin-sensitive or resistant Staphylococcus aureus strains. Moreover, when attracted and concentrated by the action of an external magnet, NP-TEICO exerted a localized inhibitory effect on S. aureus biofilm formation at low antibiotic concentration. Finally, we proved that the conjugation of glycopeptide antibiotics to IONPs reduced their intrinsic cytotoxicity toward a human cell line.

2021 ◽  
Vol 10 (48) ◽  
Marissa N. Schroeter ◽  
Safiya J. Gazali ◽  
Anutthaman Parthasarathy ◽  
Crista B. Wadsworth ◽  
Renata Rezende Miranda ◽  

We report the isolation, whole-genome sequencing, and annotation of Enterobacter sp. strain RIT 637, Pseudomonas sp. strain RIT 778, and Deinococcus sp. strain RIT 780. Disk diffusion assays using spent medium demonstrated that all bacteria produced bactericidal compounds against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 25923.

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