scholarly journals Pathogenic and Virulence Factor Detection on Viable but Non-culturable Methicillin-Resistant Staphylococcus aureus

2021 ◽  
Vol 12 ◽  
Author(s):  
Hua Jiang ◽  
Kan Wang ◽  
Muxia Yan ◽  
Qian Ye ◽  
Xiaojing Lin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Limit Of Detection ◽  
Foodborne Pathogen ◽  
Food Poisoning ◽  
Clinical Settings ◽  
Analytical Sensitivity ◽  
Vbnc State ◽  
Methicillin Resistant ◽  
Staphylococcal Enterotoxins ◽  
Sensitivity Specificity

Food safety and foodborne infections and diseases have been a leading hotspot in public health, and methicillin-resistant Staphylococcus aureus (MRSA) has been recently documented to be an important foodborne pathogen, in addition to its recognition to be a leading clinical pathogen for some decades. Standard identification for MRSA has been commonly performed in both clinical settings and food routine detection; however, most of such so-called “standards,” “guidelines,” or “gold standards” are incapable of detecting viable but non-culturable (VBNC) cells. In this study, two major types of staphylococcal food poisoning (SFP), staphylococcal enterotoxins A (sea) and staphylococcal enterotoxins B (seb), as well as the panton-valentine leucocidin (pvl) genes, were selected to develop a cross-priming amplification (CPA) method. Limit of detection (LOD) of CPA for sea, seb, and pvl was 75, 107.5, and 85 ng/μl, indicating that the analytical sensitivity of CPA is significantly higher than that of conventional PCR. In addition, a rapid VBNC cells detection method, designated as PMA-CPA, was developed and further applied. PMA-CPA showed significant advantages when compared with PCR assays, in terms of rapidity, sensitivity, specificity, and accuracy. Compared with conventional VBNC confirmation methods, the PMA-CPA showed 100% accordance, which had demonstrated that the PMA-CPA assays were capable of detecting different toxins in MRSA in VBNC state. In conclusion, three CPA assays were developed on three important toxins for MRSA, and in combination with PMA, the PMA-CPA assay was capable of detecting virulent gene expression in MRSA in the VBNC state. Also, the above assays were further applied to real samples. As concluded, the PMA-CPA assay developed in this study was capable of detecting MRSA toxins in the VBNC state, representing first time the detection of toxins in the VBNC state.

Determining the Utility of Methicillin-Resistant Staphylococcus aureus Nares Screening in Antimicrobial Stewardship

2019 ◽  
Vol 71 (5) ◽  
pp. 1142-1148 ◽  
Author(s):  
Kari A Mergenhagen ◽  
Kaitlyn E Starr ◽  
Bethany A Wattengel ◽  
Alan J Lesse ◽  
Zarchi Sumon ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bloodstream Infections ◽  
Department Of Veterans Affairs ◽  
Predictive Values ◽  
Methicillin Resistant ◽  
Entire Cohort ◽  
Clinical Culture ◽  
Specific Culture ◽  
Sensitivity Specificity

Abstract Background Treatment of suspected methicillin-resistant Staphylococcus aureus (MRSA) is a cornerstone of many antibiotic regimens; however, there is associated toxicity. The Department of Veterans Affairs (VA) hospitals screen each patient for MRSA nares colonization on admission and transfer. The objective was to determine the negative predictive value (NPV) of MRSA screening in the determination of subsequent positive clinical culture for MRSA. High NPVs with MRSA nares screening may be used as a stewardship tool. Methods This was a retrospective cohort study across VA medical centers nationwide from 1 January 2007 to 1 January 2018. Data from patients with MRSA nares screening were obtained from the VA Corporate Data Warehouse. Subsequent clinical cultures within 7 days of the nares swab were evaluated for the presence of MRSA. Sensitivity, specificity, positive predictive values, and NPVs were calculated for the entire cohort as well as subgroups for specific culture sites. Results This cohort yielded 561 325 clinical cultures from a variety of anatomical sites. The sensitivity and specificity for positive MRSA clinical culture were 67.4% and 81.2%, respectively. The NPV of MRSA nares screening for ruling out MRSA infection was 96.5%. The NPV for bloodstream infections was 96.5%, for intraabdominal cultures it was 98.6%, for respiratory cultures it was 96.1%, for wound cultures it was 93.1%, and for cultures from the urinary system it was 99.2%. Conclusion Given the high NPVs, MRSA nares screening may be a powerful stewardship tool for deescalation and avoidance of empirical anti-MRSA therapy.

scholarly journals Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

2016 ◽  
Vol 60 (10) ◽  
pp. 5688-5694 ◽  
Author(s):  
Daniel G. Meeker ◽  
Karen E. Beenken ◽  
Weston B. Mills ◽  
Allister J. Loughran ◽  
Horace J. Spencer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Limit Of Detection ◽  
Relative Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Comparable Activity ◽  
Antibiotic Delivery

ABSTRACTWe usedin vitroandin vivomodels of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistantStaphylococcus aureus(MRSA) in the specific context of an established biofilm. The results demonstrated that, underin vitroconditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when testedin vivoin a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associatedS. aureusinfections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

scholarly journals A Multicenter Study To Evaluate Ceftaroline Breakpoints: Performance in an Area with High Prevalence of Methicillin-Resistant Staphylococcus aureus Sequence Type 5 Lineage

2019 ◽  
Vol 57 (9) ◽  
Author(s):  
Ayesha Khan ◽  
Lina M. Rivas ◽  
Maria Spencer ◽  
Rodrigo Martinez ◽  
Marusella Lam ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sequence Type ◽  
Disk Diffusion ◽  
Clinical Settings ◽  
Community Settings ◽  
Methicillin Resistant ◽  
Content Type ◽  
Bmd Testing ◽  
High Prevalence

ABSTRACT Ceftaroline (CPT) is a broad-spectrum agent with potent activity against methicillin-resistant Staphylococcus aureus (MRSA). The sequence type 5 (ST5) Chilean-Cordobés clone, associated with CPT nonsusceptibility, is dominant in Chile, a region with high rates of MRSA infections. Here, we assessed the in vitro activity of CPT against a collection of MRSA isolates collected between 1999 and 2018 from nine hospitals (n = 320) and community settings (n = 41) in Santiago, Chile, and evaluated performance across testing methodologies. We found that our hospital-associated isolates exhibited higher CPT MIC distributions (MIC50 and MIC90 of 2 mg/liter) than the community isolates (MIC50 and MIC90 of 0.5 mg/liter), a finding that was consistent across time and independent of the culture source. High proportions (64%) of isolates were CPT nonsusceptible despite the absence of CPT use in Chile. Across methodologies, the Etest underestimated the MIC relative to the gold standard broth microdilution (BMD) test (MIC50 and MIC90 of 1 and 1.5 mg/liter, respectively). There was low (∼51%) categorical agreement (CA) between Etest and BMD results across CLSI and EUCAST breakpoints. The recent revision of CLSI guidelines abolished “very major error” (VME) from the previous guidelines (81%), which perform similarly to the EUCAST guidelines. The level of concordance between CLSI and EUCAST for BMD testing and Etest was >95%. Disk diffusion performed poorly relative to BMD under CLSI (CA, 55%) and EUCAST (CA, 36%) guidelines. Comparison of EUCAST to CLSI for disk diffusion (with EUCAST used as the reference) showed low agreement (CA, 25%; VME, 70%). In summary, CPT-nonsusceptible MRSA are dominant in clinical settings in Chile. Our results provide data to support the reevaluation of CPT breakpoints and to improve agreement across methodologies and agencies.

scholarly journals Polymethacrylate Sphere-Based Assay for Ultrasensitive miRNA Detection

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Samira Hosseini ◽  
Patricia Vázquez-Villegas ◽  
Richard C. Willson ◽  
Marco Rito-Palomares ◽  
Margarita Sanchez-Dominguez ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Breast Cancer Incidence ◽  
High Specific Surface Area ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Important Target ◽  
Target Analytes ◽  
High Sequence Homology ◽  
Mirna Detection ◽  
Sensitivity Specificity

Although microRNAs (miRNAs) have emerged as increasingly important target analytes, their biorecognition remains challenging due to their small size, high sequence homology, and low abundance in clinical samples. Nanospheres and microspheres have also gained increasing attention in biosensor applications due to their high specific surface area and the wide variety of compositions available. In this study, chemically designed and synthesized microspheres with active functional groups were used to promote effective miRNA immobilization resulting in better biorecognition. Upon conjugation with fluorescence-labeled complimentary probes, acylate-based spheres have indirectly detected MiR159, offering significantly enhanced analytical sensitivity, specificity, and accuracy while yielding a considerably low limit of detection (LOD) of 40 picomolar. Furthermore, MiR159 presence, which is known to be inversely correlated to breast cancer incidence and progression, was successfully detected in a competitive assay, which is promising for upgrading the current assay to clinical use.

scholarly journals Occurrence of Methicillin Resistant and Enterotoxigenic Staphylococcus aureus in Traditional Cheeses in the North West of Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Dariush Shanehbandi ◽  
Behzad Baradaran ◽  
Saeed Sadigh-Eteghad ◽  
Habib Zarredar
Keyword(s):  
Staphylococcus Aureus ◽  
Management Practices ◽  
Methicillin Resistance ◽  
Food Poisoning ◽  
Methicillin Resistant ◽  
North West ◽  
The North ◽  
Traditional Cheeses ◽  
Food Borne ◽  
Traditional Dairy Products

Traditional dairy products are potential sources of a variety of microorganisms which participate in food poisoning. Staphylococcus aureus is a conspicuous example of toxigenic bacteria causative for food-borne diseases. Moreover, resistance to methicillin is a prominent index in food hygiene studies. In the present study, we have aimed at characterization and identification of enterotoxigenic methicillin resistant S. aureus (MRSA) isolated from traditional cheeses in Azerbaijan region in the northwest of Iran during 2012. A number of phenotypical and molecular assays were utilized for screening of S. aureus. Subsequently, the prevalence of the genes responsible for the five staphylococcal enterotoxins (SEA-SEE) and also methicillin resistance gene was assessed. The outcomes of phenotypical methods were in conformity with those of the molecular procedures. The results indicated that 16% of cheese samples were contaminated by S. aureus. 110 isolates were authenticated by both phenotypical and molecular methods. All of the mentioned isolates were positive for coa, nuc, and 16S rDNA primers. 21% of these isolates were mecA positive and 60.8% of these MRSA were positive for SEs. Regarding the frequent outbreaks of enterotoxigenic MRSA, new hygiene policies and management practices should be considered to increase food safety and avoid extra treatment costs.

scholarly journals Prevalence and Molecular Characterization of Enterotoxin-Producing Strains of Staphylococcus Aureus Isolated from Serbian Dairy Cows

2016 ◽  
Vol 66 (4) ◽  
pp. 466-477 ◽  
Author(s):  
Marija Pajić ◽  
Stanko Boboš ◽  
Branko Velebit ◽  
Zoran Rašić ◽  
Vera Katić ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
Food Poisoning ◽  
Clinical Mastitis ◽  
Staphylococcal Protein A ◽  
Phylogenetic Groups ◽  
Gene Encoding ◽  
Staphylococcal Enterotoxins ◽  
Genes Encoding ◽  
The Republic

AbstractStaphylococcus aureus is known worldwide as a frequent cause of mastitis in dairy cattle. Due to the production of heath resistant enterotoxins, this pathogen is also a major cause of food poisoning among humans, with symptoms of often severe vomiting and diarrhea. The aim of our study was to determine the prevalence of enterotoxinproducing strains of S. aureus originating from samples of cows with subclinical and clinical mastitis in the Republic of Serbia. Furthermore, we analyzed the type of staphylococcal enterotoxin they produce and phylogenetic relatedness among the S. aureus isolates recovered from milk in this study. Production of staphylococcal enterotoxins A, B, C, D and E was determined by commercial immunoenzyme assay VIDAS® SET2, and presence of corresponding genes encoding enterotoxin synthesis in positive isolates confi rmed by Polymerase Chain Reaction. Enterotoxin production was determined in 5 out of 75 (6.67%) isolates of S. aureus and all of them produced staphylococcal enterotoxins C. After analyzing the nucleotide sequence of the gene encoding the synthesis of staphylococcal protein A, S. aureus isolates were assigned into 2 phylogenetic groups, including 7 clusters. All S. aureus isolates with the presence of sec gene formed one cluster even dough they originated from milk samples from different farms.

Survival of Methicillin-Resistant Staphylococcus aureus in Fish and Shrimp under Different Storage Conditions

2020 ◽  
Vol 83 (5) ◽  
pp. 844-848 ◽  
Author(s):  
POOJA SAKLANI ◽  
MANJUSHA LEKSHMI ◽  
BINAYA BHUSAN NAYAK ◽  
SANATH KUMAR
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Storage Temperature ◽  
Food Poisoning ◽  
Storage Conditions ◽  
Viable Count ◽  
Inoculum Level ◽  
Methicillin Resistant ◽  
Fresh Fish ◽  
Bombay Duck

ABSTRACT Foods that are extensively handled during preparation and stored without refrigeration are often associated with staphylococcal food poisoning. This problem is more confounding when contaminating strains belong to the methicillin-resistant Staphylococcus aureus (MRSA) group. In this study, we investigated the survivability of MRSA in two seafood matrices under different storage conditions. MRSA was inoculated at 6 and 3 log CFU/g into all sample groups of peeled shrimp (Parapeneopsis stylifera) stored at −20°C, Bombay duck fish (Harpadon nehereus) stored in ice, and dried Bombay duck fish stored at 30 ± 2°C. The populations of MRSA in frozen peeled shrimp inoculated with MRSA at 6 log CFU/g were reduced by 1.52 log CFU/g, whereas in samples inoculated with 3 log CFU/g levels remained stable after 60 days of storage. In fresh Bombay duck fish inoculated with 6 log CFU/g and stored in ice for 18 days, MRSA levels decreased by 2.75 log CFU/g. In contrast, in fresh fish inoculated with 3 log CFU/g the total viable count increased by 3.02 log CFU/g over 16 days of ice storage. In dried fish stored at 30 ± 2°C, MRSA levels declined by 3.27 log CFU/g in samples inoculated with 6 log CFU/g and by 0.91 log CFU/g in samples inoculated with 3 log CFU/g. These results suggest that the survival of MRSA depends on the temperature of storage and the inoculum level. In our study, MRSA survival was higher when inoculated at 3 log CFU/g regardless of the seafood matrix and storage temperature. HIGHLIGHTS

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