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  • 1.
    Claesson, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Staphylococci and Enterococci: Studies on activity of antimicrobial agents and detection of genes involved in biofilm formation2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Gram-positive cocci, Staphylococcus aureus, coagulase negative staphylococci (CoNS), Enterococcus faecalis and Enterococcus faecium, are the bacteria most often isolated from patients with hospital acquired infections. S. aureus is one of the most important pathogens and have a variety of virulence mechanisms which help it to infect the patient and cause tissue damage. CoNS and enterococci are low virulent bacteria and predominantly cause infections in individuals with underlying illness, individuals that have undergone surgery or with suppressed immune-system. The aims of this thesis were i) to investigate the susceptibility to different antimicrobial agents among S. aureus, CoNS, E. faecium and E. faecalis isolates from primary care centres, general hospital wards and intensive care units in Denmark, Finland, Norway and Sweden and ii) to study the prevalence of the cytolysin genes and genes involved in biofilm formation among CoNS, E. faecium and E. faecalis. The results in this thesis show that the resistance rates among S. aureus and E. faecalis is still rather low in the north European countries. Among CoNS and E. faecium resistance rates are higher and comparable with rates in other European countries and US. CoNS had statistically significant differences in susceptibility rates between the ward levels with the lower susceptibility rates found at ICUs. Continued surveillance of resistance rates to antimicrobial agents among both staphylococci and enterococci are important internationally, nationally and locally. The results in this thesis also show that all multidrug resistant and 96% of the susceptible CoNS isolates carried at least one of the atlE and aap genes or the ica operon. Among E. faecalis isolates with HLGR, belonging to a cluster of genetically related isolates, both the esp and asa1 genes were carried in a high degree while the cyl operon was less frequently found. In addition, about 30% of unique E. faecalis isolates carried two or more of the virulence genes. Among E. faecium isolates the esp gene was common but asa1 and the cyl operon was not found in any of the isolates. Both CoNS and E. faecalis isolates from hospitalised patients are well equipped with genes involved in biofilm formation. These genes, when expressed and even more in combination with resistance to antimicrobial agents, might give these isolates an advantage compared to other isolates when it comes to adhesion to artificial surfaces, persistence in the hospital environment, colonisation of hospitalised patients and to cause nosocomial infections. Further studies are needed to be able to determine which isolates that causes hospital acquired infections and to evaluate the importance of the genes involved in biofilm formation as virulence factors and about how to prevent biofilm related infections from emerging

    List of papers
    1. Susceptibility of staphylococci and enterococci to antimicrobial agents at different ward levels in four north European countries
    Open this publication in new window or tab >>Susceptibility of staphylococci and enterococci to antimicrobial agents at different ward levels in four north European countries
    Show others...
    2007 (English)In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 39, no 11-12, p. 1002-1012Article in journal (Refereed) Published
    Abstract [en]

    A multicentre susceptibility study was performed on staphylococci and enterococci isolated from patients at 3 different ward levels: primary care centres (PCCs), general hospital wards (GHWs) and intensive care units (ICUs), in Denmark, Finland, Norway and Sweden. There was a markedly higher incidence of resistance among CoNS in ICUs compared to GHWs and PCCs. Resistance rates were low among S. aureus isolates and no differences were found between the ward levels. Oxacillin resistance was found among 1.6% of S. aureus and 47% of CoNS isolates. 14% of CoNS and 0.9% of S. aureus isolates were glycopeptide intermediate. The prevalence of E. faecium isolates in this study differed significantly between the ward levels with the lowest prevalence found at PCCs. High level gentamicin resistant (HLGR) enterococci occurred in 11-25% of E. faecium and 6-20% of E. faecalis isolates. The HLGR rate was significantly higher among E. faecalis from hospitalized patients (GHWs and ICUs) compared to patients at PCCs. For enterococcal isolates, no other significant differences in antimicrobial resistance were found between the ward levels. All enterococci were teicoplanin susceptible, but decreased susceptibility to vancomycin was found among 2.0% and 0.6% of the E. faecium and E. faecalis isolates, respectively.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-39203 (URN)10.1080/00365540701472064 (DOI)47229 (Local ID)47229 (Archive number)47229 (OAI)
    Note
    Study Group, The ScopeAvailable from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
    2. Antimicrobial activity of tigecycline and comparative agents against clinical isolates of staphylococci and enterococci from ICUs and general hospital wards at three Swedish university hospitals
    Open this publication in new window or tab >>Antimicrobial activity of tigecycline and comparative agents against clinical isolates of staphylococci and enterococci from ICUs and general hospital wards at three Swedish university hospitals
    Show others...
    2009 (English)In: SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES, ISSN 0036-5548 , Vol. 41, no 3, p. 171-181Article in journal (Refereed) Published
    Abstract [en]

    The activities of tigecycline and comparative agents on staphylococci and enterococci isolated from patients at general hospital wards (GHWs) and intensive care units (ICUs) at 3 university hospitals in Sweden were investigated. Oxacillin disc diffusion and minimal inhibitory concentration with E-test were used. The presence of mecA, vanA or vanB genes was determined with PCR. Statistically significant higher incidence of clindamycin, fusidic acid, rifampicin and multidrug-resistant CoNS was found at ICUs compared to GHWs. Resistance rates were low among S. aureus. Tigecycline, linezolid and vancomycin were the only agents with high activity against methicillin-resistant S. aureus and multidrug-resistant CoNS. Resistance rates were low among E. faecalis, except for high-level gentamicin-resistant (HLGR) E. faecalis. E. faecium showed high resistance rates to ampicillin, piperacillin/tazobactam and imipenem. The HLGR rates among E. faecium were lower than the rates for E. faecalis. Tigecycline and linezolid were the only drugs with high activity against all enterococci including vancomycin-resistant enterococci. No statistically significant differences in susceptibility rates were found between the ward levels for S. aureus and enterococcal isolates and no statistically significant differences were found between the hospitals.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-17132 (URN)10.1080/00365540902721368 (DOI)
    Available from: 2009-03-07 Created: 2009-03-07 Last updated: 2010-09-17
    3. Molecular typing and detection of the aap and atlE genes and ica operon in multi-drug resistant and susceptible coagulase negative staphylococci
    Open this publication in new window or tab >>Molecular typing and detection of the aap and atlE genes and ica operon in multi-drug resistant and susceptible coagulase negative staphylococci
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The aims of the present study were to identify clinical isolates of multidrug resistant (MDR) and susceptible coagulase negative staphylococci (CoNS), (n=76) to the species level by rpoB amplicon sequencing and to detect and compare the presence of the atlE and aap genes and the ica operon between MDR (n=26) and susceptible (n=27) Staphylococcus epidermidis isolates. Detection of the atlE and aap genes and ica operon was carried out using PCR amplification. Most of the isolates were S. epidermidis, both among the MDR and susceptible CoNS. Staphylococcus haemolyticus was the only other species found in the MDR group. All MDR and 96% of the susceptible S. epidermidis isolates carried the atlE gene. The ica operon was present in about 30% of both the MDR and susceptible S. epidermidis isolates. By comparison, aap gene carriage was more common among susceptible S. epidermidis isolates (44%) than the MDR S. epidermidis isolates (27%). The atlE gene was the only gene that was found alone in the S. epidermidis genome. About 25% of the S. epidermidis isolates carried the atlE and aap genes and the ica operon simultaneously. In conclusion, rpoB gene amplicon sequencing is an easy and reliable method to identify CoNS isolates at the species and subspecies level. Both MDR and susceptible S. epidermidis isolates were found to be well equipped with adhesion and aggregation genes which might help them to adhere to artificial surfaces, colonize hospitalised patients and cause biofilm-related infections.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-59522 (URN)
    Available from: 2010-09-17 Created: 2010-09-17 Last updated: 2010-09-17
    4. Molecular detection of aggregation substance, enterococcal surface protein, and cytolysin genes and in vitro adhesion to urinary catheters of Enterococcus faecalis and E. faecium of clinical origin
    Open this publication in new window or tab >>Molecular detection of aggregation substance, enterococcal surface protein, and cytolysin genes and in vitro adhesion to urinary catheters of Enterococcus faecalis and E. faecium of clinical origin
    Show others...
    2009 (English)In: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 299, no 5, p. 323-332Article in journal (Refereed) Published
    Abstract [en]

    It has been hypothesized that nosocomial enterococci might have virulence factors that enhance their ability to colonise hospitalised patients. The objectives of this study were to investigate the prevalence of genes encoding 3 virulence factors: aggregation substance (asa1), enterococcal surface protein (esp), and 5 genes within the cytolysin operon (cylA, cylB, cylM, cylL(L), cylL(S)) and cytolysin production in 115 enterococcal clinical isolates (21 Enterococcus faecium and 94 E. faecalis). Adhesion to siliconized latex urinary catheters in relation to presence of esp was analysed in a subset of isolates. The isolates were previously characterised by pulsed-field gel electrophoresis (PFGE). esp was the only virulence gene found in E. faecium. It was found in 71% of the 21 E. faecium isolates. asa1, esp, and the cyl operon were found in 79%, 73% and 13% respectively, of the 94 E. faecalis isolates. There was a complete agreement between presence of the cyl operon and phenotypic cytolysin production. Isolates belonging to a cluster of genetically related isolates carried esp and asa1 more often when compared to unique isolates. No difference was found with respect to cyl genes. E. faecalis isolates adhered with higher bacterial densities than E. faecium. E. faecalis isolates within the same PFGE cluster adhered with similar bacterial densities, but there was no association between adhesion and the presence of esp when isolates within the same cluster were compared. In conclusion, E. faecalis isolates with high-level gentamicin resistance (HLGR) belonging to clusters of genetically related isolates widely distributed in Swedish hospitals, were likely to carry both esp and asa1. Adhesion was not affected by esp.   

    Keywords
    Enterococcus; Nosocomial infection; Aggregation substance; Enterococcal surface protein; Cytolysin; Biofilm
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-43672 (URN)10.1016/j.ijmm.2008.10.001 (DOI)74509 (Local ID)74509 (Archive number)74509 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
  • 2.
    Claesson, Carina
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Hällgren, Anita
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Nilsson, Maud
    Linköping University, Department of Molecular and Clinical Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Erik
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Hanberger, Håkan
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Nilsson, Lennart
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Susceptibility of staphylococci and enterococci to antimicrobial agents at different ward levels in four north European countries2007In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 39, no 11-12, p. 1002-1012Article in journal (Refereed)
    Abstract [en]

    A multicentre susceptibility study was performed on staphylococci and enterococci isolated from patients at 3 different ward levels: primary care centres (PCCs), general hospital wards (GHWs) and intensive care units (ICUs), in Denmark, Finland, Norway and Sweden. There was a markedly higher incidence of resistance among CoNS in ICUs compared to GHWs and PCCs. Resistance rates were low among S. aureus isolates and no differences were found between the ward levels. Oxacillin resistance was found among 1.6% of S. aureus and 47% of CoNS isolates. 14% of CoNS and 0.9% of S. aureus isolates were glycopeptide intermediate. The prevalence of E. faecium isolates in this study differed significantly between the ward levels with the lowest prevalence found at PCCs. High level gentamicin resistant (HLGR) enterococci occurred in 11-25% of E. faecium and 6-20% of E. faecalis isolates. The HLGR rate was significantly higher among E. faecalis from hospitalized patients (GHWs and ICUs) compared to patients at PCCs. For enterococcal isolates, no other significant differences in antimicrobial resistance were found between the ward levels. All enterococci were teicoplanin susceptible, but decreased susceptibility to vancomycin was found among 2.0% and 0.6% of the E. faecium and E. faecalis isolates, respectively.

  • 3.
    Claesson, Carina
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Monstein, Hans-Jürg
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine.
    Nilsson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Molecular typing and detection of the aap and atlE genes and ica operon in multi-drug resistant and susceptible coagulase negative staphylococciManuscript (preprint) (Other academic)
    Abstract [en]

    The aims of the present study were to identify clinical isolates of multidrug resistant (MDR) and susceptible coagulase negative staphylococci (CoNS), (n=76) to the species level by rpoB amplicon sequencing and to detect and compare the presence of the atlE and aap genes and the ica operon between MDR (n=26) and susceptible (n=27) Staphylococcus epidermidis isolates. Detection of the atlE and aap genes and ica operon was carried out using PCR amplification. Most of the isolates were S. epidermidis, both among the MDR and susceptible CoNS. Staphylococcus haemolyticus was the only other species found in the MDR group. All MDR and 96% of the susceptible S. epidermidis isolates carried the atlE gene. The ica operon was present in about 30% of both the MDR and susceptible S. epidermidis isolates. By comparison, aap gene carriage was more common among susceptible S. epidermidis isolates (44%) than the MDR S. epidermidis isolates (27%). The atlE gene was the only gene that was found alone in the S. epidermidis genome. About 25% of the S. epidermidis isolates carried the atlE and aap genes and the ica operon simultaneously. In conclusion, rpoB gene amplicon sequencing is an easy and reliable method to identify CoNS isolates at the species and subspecies level. Both MDR and susceptible S. epidermidis isolates were found to be well equipped with adhesion and aggregation genes which might help them to adhere to artificial surfaces, colonize hospitalised patients and cause biofilm-related infections.

  • 4.
    Claesson, Carina
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Nilsson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Kronvall, Goeran
    Karolinska Institute.
    Walder, Mats
    Malmö University Hospital.
    Sorberg , Mikael
    Karolinska Institute.
    Antimicrobial activity of tigecycline and comparative agents against clinical isolates of staphylococci and enterococci from ICUs and general hospital wards at three Swedish university hospitals2009In: SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES, ISSN 0036-5548 , Vol. 41, no 3, p. 171-181Article in journal (Refereed)
    Abstract [en]

    The activities of tigecycline and comparative agents on staphylococci and enterococci isolated from patients at general hospital wards (GHWs) and intensive care units (ICUs) at 3 university hospitals in Sweden were investigated. Oxacillin disc diffusion and minimal inhibitory concentration with E-test were used. The presence of mecA, vanA or vanB genes was determined with PCR. Statistically significant higher incidence of clindamycin, fusidic acid, rifampicin and multidrug-resistant CoNS was found at ICUs compared to GHWs. Resistance rates were low among S. aureus. Tigecycline, linezolid and vancomycin were the only agents with high activity against methicillin-resistant S. aureus and multidrug-resistant CoNS. Resistance rates were low among E. faecalis, except for high-level gentamicin-resistant (HLGR) E. faecalis. E. faecium showed high resistance rates to ampicillin, piperacillin/tazobactam and imipenem. The HLGR rates among E. faecium were lower than the rates for E. faecalis. Tigecycline and linezolid were the only drugs with high activity against all enterococci including vancomycin-resistant enterococci. No statistically significant differences in susceptibility rates were found between the ward levels for S. aureus and enterococcal isolates and no statistically significant differences were found between the hospitals.

  • 5.
    Hällgren, Anita
    et al.
    Department ofMolecularandClinicalMedicine Linköping University.
    Claesson, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Saeedi, Baharak
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Monstein, Hans-Jurg
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine.
    Hanberger, Håkan
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Nilsson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Molecular detection of aggregation substance, enterococcal surface protein, and cytolysin genes and in vitro adhesion to urinary catheters of Enterococcus faecalis and E. faecium of clinical origin2009In: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 299, no 5, p. 323-332Article in journal (Refereed)
    Abstract [en]

    It has been hypothesized that nosocomial enterococci might have virulence factors that enhance their ability to colonise hospitalised patients. The objectives of this study were to investigate the prevalence of genes encoding 3 virulence factors: aggregation substance (asa1), enterococcal surface protein (esp), and 5 genes within the cytolysin operon (cylA, cylB, cylM, cylL(L), cylL(S)) and cytolysin production in 115 enterococcal clinical isolates (21 Enterococcus faecium and 94 E. faecalis). Adhesion to siliconized latex urinary catheters in relation to presence of esp was analysed in a subset of isolates. The isolates were previously characterised by pulsed-field gel electrophoresis (PFGE). esp was the only virulence gene found in E. faecium. It was found in 71% of the 21 E. faecium isolates. asa1, esp, and the cyl operon were found in 79%, 73% and 13% respectively, of the 94 E. faecalis isolates. There was a complete agreement between presence of the cyl operon and phenotypic cytolysin production. Isolates belonging to a cluster of genetically related isolates carried esp and asa1 more often when compared to unique isolates. No difference was found with respect to cyl genes. E. faecalis isolates adhered with higher bacterial densities than E. faecium. E. faecalis isolates within the same PFGE cluster adhered with similar bacterial densities, but there was no association between adhesion and the presence of esp when isolates within the same cluster were compared. In conclusion, E. faecalis isolates with high-level gentamicin resistance (HLGR) belonging to clusters of genetically related isolates widely distributed in Swedish hospitals, were likely to carry both esp and asa1. Adhesion was not affected by esp.   

  • 6.
    Hällgren, Anita
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Claesson, Carina
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Saeedi, Baharak
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Monstein, Hans-Jürg
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Hanberger, Håkan
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Nilsson, Lennart E.
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Frequency of aggregation substance, cytolysin and enterococcal surface protein in vitro adhesion to urinary catheters of E. faecalis and E. faecium of clinical originManuscript (preprint) (Other academic)
    Abstract [sv]

    Enterococcal isolates, 21 E. faecium and 94 E. faecalis, isolated from blood cultures, rectal specimens and various other clinical samples were examined for the presence of the virulence factors hemolysin/cytolysin, aggregation substance (asa1) and enterococcal surface protein (esp). The isolates were previously characterized by pulsed-field gel electrophoresis (PFGE). Adhesion to siliconized latex urinary catheters was analysed in 14 clinical isolates and 3 control strains. Densities of adhering bacteria were determined by a bioluminescence assay of bacterial ATP. The only virulence factor found in E. faecium, esp, was found in 71% of the 21 E. faceium isolates. Cytolysin production, asa1 and esp were found in 13%, 79% and 73%, respectively, of the 94 E. faecalis isolates. Isolates belonging to a cluster of genetically related isolates differed significantly with respect to carriage of esp and asa1 compared to unique isolates, with the virulence factors more commonly found among clustered isolates (p<0.01). No difference was found with respect to cytolysio production (p = 0.76). E. faecalis isolates adhered with higher bacterial densities than E. faecium. E. faecalis isolates within the same PFGE cluster adhered with similar bacterial densities, but there was no association between adhesion and the presence of esp when isolates within the same cluster were compared (p = 0.38 and 0.64).

  • 7.
    Larsson, Jenny
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Persson, Carina
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundqvist Gustafsson, Helen
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Anti-inflammatory effects of a titanium-peroxy gel: role of oxygen metabolites and apoptosis2004In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 68, no 3, p. 448-457Article in journal (Refereed)
    Abstract [en]

    Polymorphonuclear neutrophils (PMN) are among the first inflammatory cells to arrive at an implant interface, where they encounter with the foreign material and may produce reactive oxygen species (ROS). During the interaction between titanium and ROS, titanium-peroxy (Ti-peroxy) compounds may be formed. We used a Ti-peroxy gel, made from titanium and hydrogen peroxide, to study the effects of Ti-peroxy compounds on PMN. In the absence of serum, the Ti-peroxy gel decreased the oxidative response of PMN to yeast and PMA and reduced PMN apoptosis without inducing necrosis. These effects could not be ascribed to the release of hydrogen peroxide from the Ti-peroxy gel, because a steady-state hydrogen peroxide producing system failed to mimic the effects of the gel. The effects were similarly unaffected when PMN were preincubated with β2-integrin antibodies, questioning the involvement of adhesion molecules. Nevertheless, when a filter was used to separate the Ti-peroxy gel from the cells, the gel effect on PMN life span was abolished, pointing to a contact-dependent mechanism. In the presence of serum, the Ti-peroxy gel had no effect on the PMN oxidative response and life span, but appeared rather inert. In summary, this study demonstrates that the Ti-peroxy gel has potentially anti-inflammatory properties through a combined peroxide and physical contact effect, supporting the notion that interactions between titanium and inflammatory cells are responsible for the good performance of titanium in vivo.

  • 8.
    Nilsdotter-Augustinsson, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Claesson, Carina
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lundqvist Gustafsson, Helen
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Öhman, Lena
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Adherence of Staphylococcus epidermidis to extracellular matrix proteins and effects of fibrinogen-bound bacteria on oxidase activity and apoptosis in neutrophils2005In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 113, no 5, p. 361-373Article in journal (Refereed)
    Abstract [en]

    Staphylococcus epidermidis often causes foreign-body infections such as those associated with hip prostheses, but the underlying pathogenic mechanisms are not fully understood. We performed spectrophotometry to study the ability of S. epidermidis to bind to immobilised fibrinogen, fibronectin, vitronectin, and collagen. The strains were isolated from infected hip prostheses or from normal flora and the well-known protein-binding strain Staphylococcus aureus Cowan was used as positive control. We also analysed the interaction between neutrophils and a fibrinogen-bound prosthesis-derived strain of S. epidermidisby measuring chemiluminescence to determine the neutrophil oxidative response and binding of annexin V to indicate neutrophil apoptosis. We found that binding of S. epidermidis to extracellular matrix proteins varied under different growth conditions, and that prosthesis isolates adhered better to vitronectin than did strains from normal flora. The oxidative response caused by fibrinogen-bound S. epidermidis was not above the background level, which was in marked contrast to the distinct response induced by fibrinogen-associated S. aureus Cowan. Furthermore, fibrinogen-adhering S. epidermidis retarded neutrophil apoptosis. We conclude that surface-bound S. epidermidis induces only a weak inflammatory response, which in combination with the ability of the adherent bacteria to retard neutrophil apoptosis may contribute to low-grade inflammation and loosening of prostheses.

  • 9.
    Tevell, S.
    et al.
    Karlstad Hospital, Sweden / Örebro University, Sweden.
    Claesson, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Microbiology.
    Hellmark, B.
    Örebro University Hospital, Sweden.
    Söderquist, B.
    Örebro University / Örebro University Hospital, Sweden.
    Nilsdotter-Augustinsson, Åsa
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Heterogeneous glycopeptide intermediate Staphylococcus epidermidis isolated from prosthetic joint infections2014In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 33, no 6, p. 911-917Article in journal (Refereed)
    Abstract [en]

    Methicillin-resistant Staphylococcus epidermidis (MRSE) poses a major problem in prosthetic joint infections (PJIs). Vancomycin is often considered the drug of choice in the empirical treatment of staphylococcal PJIs. As recent decades have seen reports of heterogeneous glycopeptide intermediate S. aureus (hGISA), our aim was to examine the prevalence of heterogeneous glycopeptide intermediate S. epidermidis (hGISE) in PJIs. S. epidermidis isolates (n = 122) from 119 patients in three Swedish counties between 1993 and 2012 were included. All were isolated from perioperative tissue samples from revision surgery in clinically verified PJIs. Antimicrobial susceptibility testing against staphylococcal antibiotics was performed. The macromethod Etest (MME) and glycopeptide resistance detection (GRD) Etest were used to detect hGISE. Standard minimal inhibitory concentration (MIC) determination revealed no vancomycin-resistant isolates, while teicoplanin resistance was detected in 14 out of 122 isolates (11.5 %). hGISE was found in 95 out of 122 isolates (77.9 %), 64 out of 67 of isolates with teicoplanin MIC >2 mg/L (95.5 %) and 31 out of 55 of isolates with teicoplanin MIC ≤2 mg/L (56.4 %). Thus, the presence of hGISE cannot be ruled out by teicoplanin MIC ≤2 mg/L alone. Multidrug resistance was detected in 86 out of 95 hGISE isolates (90.5 %) and in 16 out of 27 isolates (59.3 %), where hGISE could not be detected. In conclusion, hGISE detected by MME or GRD was common in this material. However, hGISE is difficult to detect with standard laboratory diagnostic routines. Glycopeptide treatment may not be sufficient in many of these PJIs, even if standard MIC classifies the isolated S. epidermidis as susceptible.

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