Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that has spread into the community since the 90s. In general, the community-associated (CA- MRSA) strains are more virulent, but less resistant to antimicrobials than the hospital- acquired strains (HA-MRSA). Some lineages of MRSA such as sequence type 8 have been transmitted more successfully around the world than others and there are situations where a dominant lineage has been replaced by a new one. The factors that are crucial for the selection of dominant lineage are often not clear. As part of this thesis, a longitudinal study of MRSA epidemiology in the Motol University Hospital during the period of 2018-2020 was performed and the occurrence of MRSA clonal complexes was characterized. A multicenter study of the epidemiological situation of MRSA in Slovakia during the period of January - April 2020 was also performed concomitantly. Moreover, several isolates from dominant lineages were further characterized by their phenotype. In the Motol University Hospital study, it was found that the HA-MRSA of the clonal complex 5 dominates and is represented mainly by spa-type t586; a finding that concurs with recent studies from the Czech Republic. In Slovakia, similar to the Czech Republic, MRSA lineages from clonal...

Meticillinresistenta Stafylokocker aureus är Stafylokocker aureus som är resistenta mot flera antibiotika. Meticillinresistenta Stafylokocker aureus samt infektioner associerade till det är ett välkänt internationellt problem och delas in i vårdförvärvad och samhällsförvärvad. Vårdförvärvade Meticillinresistenta Stafylokocker aureus är de som sprids på sjukhus, medan den sistnämnda sprids ute i samhället. Individer kan bli koloniserade med Meticillinresistenta Stafylokocker aureus utan att ha symtom och det kan spridas genom luftburen, direkt och indirekt smitta. Den dominerande spridningen sker mellan hälso- och sjukvårdspersonalens händer till patienten. Det som i första hand bör göras av all hälso- sjukvårdspersonal för att minska spridningen är att tillämpa de basala hygienrutinerna. Patienter med Meticillinresistenta Stafylokocker aureus isoleras när de är inneliggande på sjukhus. Det finns inga globala riktlinjer gällande bekämpningen av Meticillinresistenta Stafylokocker aureus. Riktlinjer utvecklas i olika länder baserade på det specifika landets situation samt sjukvårdsekonomi. Stigmatisering av patienter med Meticillinresistenta Stafylokocker aureus kan ske under olika former, exempelvis läkarundersökningar. Syftet var att beskriva patienters upplevelser av Meticillinresistenta Stafylokocker aureus i det dagliga livet. Metoden som valdes för att besvara syftet var en litteraturbaserad studie som innebar kritisk granskning av vetenskapliga originalartiklar. Datainsamlingen genomfördes under april månad år 2011 genom databassökningar i PubMed samt via manuella sökningar. Resultatet baserades på 17 vetenskapliga original artiklar som sammanställdes och presenterades i en matris samt klassificerades och värderades. Resultatet påvisade att upplevelsen kring besked av diagnos var chockerande, likgiltigt samt patienterna upplevde en känsla av orenhet. Upplevelsen av behov av kunskap och information angående Meticillinresistenta Stafylokocker aureus varierade, patienter upplevde att det fanns brist på kunskap hos hälso- och sjukvårdspersonalen. I det dagliga livet kunde Meticillinresistenta Stafylokocker aureus påverka möjligheten att få arbete samt tillfällen att utöva fritidsaktiviteter. Flera upplevde en känsla av stigmatisering, oro, ångest, ilska samt depression och bärarkort upplevdes påtvingat. Patienterna upplevde även att de blev behandlade olika inom hälso- och sjukvården på grund av bärarskap av Meticillinresistenta Stafylokocker aureus. Vid behov av vård beskrevs isolering som både positivt och negativt. Det upplevdes att hälso- och sjukvårdspersonalen inte alltid följde gällande hygienrutiner. Patienter var rädda att smitta andra med Meticillinresistenta Stafylokocker aureus och flera var extra noggranna med sin hygien, en del var dessutom rädda över att bli utstötta. Slutsatsen blev att patienter upplever att Meticillinresistenta Stafylokocker aureus oftast påverkar hela livssituationen. Först med starka känslor vid besked kring diagnos därefter upplevelsen av att inte få tillräcklig information kring smittspridning samt eventuell behandling från hälso- och sjukvårdspersonal. Patienter upplever en brist på kunskap hos hälso- och sjukvårdspersonalen samt att de med Meticillinresistenta Stafylokocker aureus beskriver en rädsla över att smitta andra.

Bakgrund: Methicillin-resistenta staphylococcus aureus (MRSA) är en bakterie som utvecklat resistens mot antibiotika. MRSA är ett av sjukvårdens största hygien-relaterade problem som ökar världen över. Smittspridning sker via direkt och indirekt kontaktsmitta. Konstateras smittan ska patienten alltid ha isolerings- och barriärvård vilket vanligtvis sker på en infektionsavdelning.Syfte: Syftet med denna studie var att beskriva MRSA patienters upplevelser av omhändertagandet inom vården.Metod: För att besvara studiens syfte gjordes en litteraturstudie med granskning av studier med kvalitativ ansats. Litteratursökningen utfördes i databaserna PubMed och CINAHL. Elva kvalitativa vetenskapliga artiklar granskades och sammanställdes till ett resultat.Resultat: Litteraturstudiens resultat delas in i fyra kategorier med en underkategori: Att känna skam och skuld med underkategorin att känna sig stigmatiserad, känsla av utanförskap, att känna sig kränkt och bristande kunskap och information. Resultatet visade att MRSA är ett ämne som varken patienter eller personal har mycket kunskap om. Kunskapen och informationen är bristande vilket kan påverka upplevelsen av bemötandet. Patienterna upplevde ett dåligt bemötande vilket hade stor påverkan på deras psykiska mående.Konklusion: Det som framkom i resultatet var att MRSA är ett ämne som kräver fortsatt forskning. Kunskapen om MRSA hos vårdpersonalen var bristfällig och måste utvecklas för att ett gott omhändertagande ska kunna ges och för att smittspridningen ska minskas.Nyckelord: Kunskapsbrist, känslor, MRSA, omhändertagande och upplevelser. / Background: Methicillin-resistant staphylococcus aureus (MRSA) is a bacterium that has developed a resistance to antibiotics. MRSA is one of hospitals greatest hygiene-related problems that are increasing around the world. The infection spreads through both direct and indirect contact. If the infection is detected, the patient should be placed in isolation with barrier care that usually occurs in an infection ward.Purpose: The purpose of this study was to describe MRSA patients' experiences of care within healthcare.Method: A literarture review was conducted of qualitative studies. The databases PubMed and CINAHL was used for literature search. Eleven qualitative papers were reviewed and compiled to a result.Results: The results of the literary review were divided into four categories with one subcategory: to feel shame and guilt with the subcategory to feel stigmatized, too feel like an outsider, to feel violated and lack of knowledge and information. The result showed that MRSA is a topic that neither patient nor staff has a lot of knowledge of. The knowledge and the information were inadequate which could affect the experience of the treatment. The patients were not met with good treatment which had a major impact on their psychological well being.Conclusion: What was found in the result was that MRSA is a topic that is in need of continued research overall. The knowledge of MRSA in healthcare personnel was inadequate and must be increased in order for proper care to be carried out and to reduce the risk of spreading the infection.Keywords: Emotions, experience, healthcare, lack of knowledge, MRSA.

Methicillin-resistenta Staphylococcus aureus (MRSA) har blivit en allt vanligare patogen inom sjukvården och i samhället. MRSA orsakar infektioner som inte kan behandlas med β-laktamantibiotika. För att förhindra spridning genomgår patienter och sjukvårdspersonal screening-tester. I dessa screening-tester ingår PCR-analys av mecA, nuc och/eller Sa442. MecA är lokaliserad på Staphylococcal Cromosomal Cassette mec (SCCmec) och används som en markör för MRSA medan nuc och Sa442 anger S. aureus. PCR-positiva isolat odlas ut på agarplattor efter anrikning i en selektiv buljong. Kolonier av S. aureus resistensbestäms mot cefoxitin som MRSA är resistent mot. Idag används dock PCR-analys av mecA som en referensmetod för diagnostisering av MRSA. Under det senaste årtiondet har även rapporterats fynd av stammar som enligt resistensmönster är MRSA men som har utfallit negativt för mecA i PCR. Under 2011 rapporterades en ny variant av SCCmec och en ny variant av mecA, mecALGA251. I denna studie har en realtids-PCR tagits fram för att identifiera den nya varianten, mecALGA251. Denna PCR användes för att undersöka 43 kliniska isolat, fyra cefoxitin-känsliga S. aureus från rutinen och tre referensstammar. De kliniska isolaten hade samlats in under perioden 2004 – 2011 och hade uppvisat cefoxitin-resistens men gett negativt resultat i mecA-PCR. Totalt 40 av de 43 cefoxitin-resistenta kliniska isolaten visades bära mecALGA251. Resistensbestämningar med diskdiffusion och E-test mot cefoxitin, oxacillin, cefuroxim och cefotaxim visade att denna typ av MRSA inte kan skiljas från klassisk MRSA. Resultaten visar att cefoxitin-resistenta S. aureus isolat som bär mecALGA251 finns bland skånska patienter. De visar också att det finns cefoxitin-resistent S. aureus som saknar både klassiska mecA och mecALGA251. Dessa stammar har inte studerats vidare i denna studie. / Methicillin-resistant Staphylococcus aure s (MRSA) has become a more frequent pathogen within health care facilities and the community. MRSA causes infections that can’t be treated with β-lactamantibiotics. To prevent the spread of MRSA, patients and medical personnel undergo screening-tests. In the screening-tests PCR-analysis of mecA, nuc and/or Sa442 is included. MecA is located at Staphylococcal Chromosomal Cassette mec (SCCmec) and is a marker for MRSA, whereas nuc and Sa442 state regular S. Aureus infections. PCR-positive isolates are grown on agar plates after enrichment in selective broth. Colonies of S. aureus are tested for cefoxitin susceptibility to which MRSA is resistant. PCR-analysis of mecA is the reference method that is being used today when MRSA is being diagnosed. During the last decade cefoxitin-resistant strains that lack mecA in the PCR has been reported. In 2011 a new variant of SCCmec and a new variant of mecA, mecALGA251 was reported. In this study a new real-time-PCR has been developed in order to identify mecALGA251. The new PCR protocol was being used to examine 43 clinical isolates, four cefoxitin-susceptible S. aureus from the routine and three reference strains were examined. The clinical isolates had been collected during the period 2004-2011 and were cefoxitin-resistant but lacked mecA. In total of 40 of the 43 cefoxitin-resistant was PCR positive for mecALGA251. Susceptibility testing with disk diffusion and E-test for cefoxitin, oxacillin, cefuroxime and cefotaxime showed that this type of MRSA can’t be distinguished from regular MRSA. The results showed that cefoxitin-resistantS. aureus isolates carrying mecALGA251 exist among patients in Skåne County. One cefoxitin-resistant S. aureus isolate lacked both classic mecA and mecALGA251, which indicates that other mechanisms may exist, however these results has not been further analysed in this study.

Methicillin-resistant Staphylococcus aureus (MRSA) is a variant of the more common Methicillin-Susceptible Staphylococcus aureus (MSSA), an opportunistic pathogen a portion of the human population carries as normal bacterial flora. When an outbreak of MRSA occurs, it is often important to determine if and how these strains are related to each other. In this report two different types of epidemiological methods were combined (namely Multi-Locus Sequence Typing and staphylococcal protein A-typing), in order to reduce workload, costs and time. A panel of resistance and virulence markers was also added to gather as much information about the culture as possible in a single analysis. To test the viability of the method extracted DNA and heat-treated bacterial cultures of both MRSA and MSSA were amplified with a curated panel of primers. These products were later sequenced with Nanopore’s MinION using the Flongle flow-cell. The method showed promise and worked as intended regarding the staphylococcal protein A-typing and the panel of resistance and virulence markers. However, the Multi-Locus Sequence Typing did still require optimization in order to be used clinically. In summary the project can be viewed as a success since it succeeded in being more time, cost and work efficient than many of its predecessors, when the problems with the Multi-Locus Sequence Typing are solved.

Methicillin Resistant Staphylococcus Aureus (MRSA) has been receiving significant attention, highlighting an increased risk of infectious transmission associated with athletic participation. As MRSA infections are becoming increasing virulent, athletic trainers are presented with immediate prevention challenges. While recommendations have been offered by the Centers for Disease Control and Prevention outlining basic prevention procedures, adherence to proposed guidelines and actual perception of the threat still pose the greatest hurdles to eradication of MRSA. Success in control and prevention of transmission of MRSA in athletic environments can be furthered by first investigating the perceptions of the problem in one of the first line of defense for athletes—their athletic trainers. Of particular importance are the perceptions of trainers' adherence to guidelines, perceptions of protocol standards, and relative threat of MRSA in the athletic environment. This study attempts to determine these perceptions and predict how athletic trainers will receive and adhere to standardized guidelines through written policy for MRSA prevention. Results reflect an increase in the awareness of MRSA as a threat to athletics since 2004. Overall positive perception of the development of guidelines and protocols specifically targeted to prevention of MRSA transmission in the athletic environment were also defined through this study. Athletic trainers surveyed expressed strong desire for additional training in procedures specific to reducing transmission of MRSA to prevent outbreaks. / Ph. D.

Staphylococcus aureus is a pathogen responsible for a wide variety of life-threatening diseases such as bacteremia, endocarditis, and pneumoniae. S. aureus has been a major concern in recent years due to the rampant spread of antibiotic resistance. The ability of S. aureus to form biofilms aids in the spread of antibiotic resistance as biofilms are a known hotspot for horizontal gene transfer. Biofilms also protect cells from host immune responses and antibiotics, making these infections very difficult to treat. The matrix of S. aureus biofilms can be made of polysaccharides, protein, and DNA. In these studies, we sought to elucidate how biofilm composition correlates with source of isolation in S. aureus strains, the role of biofilm-related genes in biofilm composition, and the potential role of biofilm eDNA in horizontal gene transfer. The composition and strength of biofilms made by a variety of hospital and meat-associated strains of S. aureus was measured using crystal violet (CV) staining and DNase or proteinase K treatment. Biofilm polysaccharide concentration was also measured using the phenol sulfuric-acid assay. We found that biofilms of hospital-associated isolates tend to have more protein and polysaccharides while those of meat isolates contain significantly more DNA. We also investigated the effects that biofilm-related genes have on biofilm formation and composition by analyzing specific transposon mutants of genes suggested by previous studies to play a role in biofilm development. Transposon insertions in agrA, atl, clfA, fnbA, purH, and sarA significantly weakened biofilms as compared to a wild-type control, whereas the acnA insertion mutant produced a significantly stronger biofilm. Biofilms formed from these mutant strains were treated (or mock-treated) with DNase or proteinase K and tested with phenol and sulfuric acid to determine what role these genes play in biofilm composition. We found that the atl and sarA insertion mutants produced biofilms with greater polysaccharide concentrations than the wild-type. Since many of the isolates produced biofilms composed of DNA, we investigated the potential role of this extracellular DNA in horizontal gene transfer. Strains with complementary antibiotic resistances and susceptibilities were paired together and co-cultured together in a biofilm and plated onto double antibiotic plates to select for possible gene transfer. Putative gene transfer was found to be largely biofilm dependent and enhanced with the addition of subinhibitory concentrations of antibiotics added to the biofilm. Potential transformation was also shown to naturally occur in many strains when naked DNA was added to a single strain biofilm and was also aided with the addition of subinhibitory antibiotics.

The pathogenicity and intractable nature of the microorganism Staphylococcus aureus (SA) has been long documented and highlighted by many health care agencies, with emphasis on its ability to exploit the human coagulation system to deadly effect. Two drugs from a class of inhibitors known as Direct Thrombin Inhibitors (DTI) have been shown to have a substantial effect on the enzyme secreted by SA known as Staphylocoagulase (SC), but up until now the application of this potential treatment has been limited. This paper strives to supply an overview of these clinical studies and propose a novel protocol for testing DTI's on SA in an in vitro setting. Three DTIs have been identified, including two already tested in clinical trials, and computational molecular docking simulations have been applied to elucidate the mechanisms of action for the inhibition. An additional DTI has been developed using these mechanisms as principles and shows promise for future development. After conducting this preliminary protocol, it has been found that running a minimum inhibitory concentration test across several tubes with varying degrees of these DTIs demonstrated varying levels of coagulation consistent with the findings of clinical research papers. It is fair to conclude, then, that after development or discovery of new coagulase inhibitors, they can be quickly and accurately tested against existent DTIs to gauge their efficacy.

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