Publications by authors named "Kåre Bergh"

34 Publications

Novel Peptides Targeting the β-Clamp Rapidly Kill Planktonic and Biofilm Both and .

Front Microbiol 2021 17;12:631557. Epub 2021 Mar 17.

Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.

Antimicrobial resistance is an increasing threat to global health and challenges the way we treat infections. Peptides containing the PCNA interacting motif APIM (APIM-peptides) were recently shown to bind to the bacterial PCNA homolog, the beta (β)-clamp, and to have both antibacterial and anti-mutagenic activities. In this study we explore the antibacterial effects of these peptides on , a bacterial species commonly found in prosthetic joint infections (PJI). Drug-resistant bacterial isolates from PJIs often lead to difficult-to-treat chronic infections. We show that APIM-peptides have a rapid bactericidal effect which when used at sublethal levels also increase the efficacy of gentamicin. In addition, APIM-peptides reduce development and eliminate already existing biofilm. To study the potential use of APIM-peptides to prevent PJI, we used an bone graft model in rats where APIM-peptide, gentamicin, or a combination of the two was added to cement. The bone grafts containing cement with the combination was more effective than cement containing only gentamicin, which is the current standard of care. In summary, these results suggest that APIM-peptides can be a promising new drug candidate for anti-infective implant materials to use in the fight against resistant bacteria and chronic PJI.
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http://dx.doi.org/10.3389/fmicb.2021.631557DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009970PMC
March 2021

Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study.

J Orthop Surg Res 2020 Nov 11;15(1):522. Epub 2020 Nov 11.

Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.

Background: In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy.

Methods: We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed.

Results: Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner.

Conclusion: There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.
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http://dx.doi.org/10.1186/s13018-020-02052-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661210PMC
November 2020

Establishment of an in vivo rat model for chronic musculoskeletal implant infection.

J Orthop Surg Res 2020 Jan 21;15(1):23. Epub 2020 Jan 21.

Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.

Background: The aim of the study was to establish an experimental chronic musculoskeletal infection model in vivo characterized by (a) a small bacterial inoculum, (b) no general or local signs of infection, (c) several parallels (implants) in each animal and finally (d) a model that is technically easy to perform.

Methods: Bone xenografts with steel plates were implanted intramuscularly in rats. To the xenografts, different inocula of Staphylococcus aureus and two strains of Staphylococcus epidermidis were added. The animals were observed for different time periods before the removal of the xenografts. The xenografts and steel plates were subjected to quantitative bacterial culture after sonication. Additional steel plates were subjected to scanning electron microscopy (SEM) for visualization of biofilm formation.

Results: Inoculation of bone grafts with S. aureus did produce a pyogenic infection in all animals. A chronic infection was established in rats where the bone grafts were inoculated with S. epidermidis. A bacterial inoculum of 100 colony-forming units (CFU) of S. epidermidis was adequate as a minimum infective dose. During a period of up until 42 days, the animals infected with S. epidermidis had no general or local signs of infection. According to the results of the quantitative bacterial culture of sonicate fluid and SEM, a biofilm was developed on all implants.

Conclusion: In the present in vivo model, a very small bacterial inoculum succeeded in establishing a chronic musculoskeletal implant infection where a biofilm was formed on the implants. The experimental model is easy to perform and allows several implants in each animal. The model could be useful for the study of biofilm formation in vivo on different implants and different surfaces.
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http://dx.doi.org/10.1186/s13018-020-1546-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6975053PMC
January 2020

Investigation of an outbreak caused by antibiotic-susceptible Klebsiella oxytoca in a neonatal intensive care unit in Norway.

Acta Paediatr 2019 01 9;108(1):76-82. Epub 2018 Oct 9.

Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.

Aim: Klebsiella spp. have been stated to be the most frequent cause of neonatal intensive care unit (NICU) outbreaks. We report an outbreak of Klebsiella oxytoca in a NICU at a tertiary care hospital in Norway between April 2016 and April 2017. This study describes the outbreak, infection control measures undertaken and the molecular methods developed.

Methods: The outbreak prompted detailed epidemiological and microbial investigations, where whole-genome sequencing (WGS) was particularly useful for both genotyping and development of two new K. oxytoca-specific real-time PCR assays. Routine screening of patients, as well as sampling from numerous environmental sites, was performed during the outbreak. A bundle of infection control measures was instigated to control the outbreak, among them strict cohort isolation.

Results: Five neonates had symptomatic infection, and 17 were found to be asymptomatically colonised. Infections varied in severity from conjunctivitis to a fatal case of pneumonia. A source of the outbreak could not be determined.

Conclusion: This report describes K. oxytoca as a significant pathogen in a NICU outbreak setting and highlights the importance of developing appropriate microbiological screening methods and implementing strict infection control measures to control the outbreak in a setting where the source could not be identified.
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http://dx.doi.org/10.1111/apa.14584DOI Listing
January 2019

Rapid discrimination of Staphylococcus epidermidis genotypes in a routine clinical microbiological laboratory using single nucleotide polymorphisms in housekeeping genes.

J Med Microbiol 2018 Feb 2;67(2):169-182. Epub 2018 Jan 2.

Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.

Purpose: Staphylococcus epidermidis colonies often display several morphologies and antimicrobial susceptibility patterns when cultured from device-related infections, and may represent one or multiple genotypes. Genotyping may be helpful in the clinical interpretation, but is time consuming and expensive. We wanted to establish a method for rapid discrimination of S. epidermidis genotypes for use in a routine microbiology laboratory.

Methodology: A real-time PCR targeting eight discriminatory class I or II single-nucleotide polymorphisms (SNPs) in six of the seven housekeeping genes was constructed. Post PCR, high-resolution melt (HRM) analysis using EvaGreen as fluorophore discriminated amplicons based on their percentage GC content.

Results: In silico, 42 representative sequence types (STs), including all major MLST group and subgroup founders, were separated into 23 different cluster profiles with a Simpson's index of diversity of 0.97. By HRM-PCR, 11 commonly encountered hospital and outbreak STs were separated into eight HRM patterns.

Conclusion: This method can rapidly establish whether S. epidermidis strains belong to different genotypes. It can be used in patients with S. epidermidis infections, as an aid in outbreak investigations and to select strains for investigation with more discriminatory methods, saving workload and costs. Results may be obtained the same day as culture results. Its strength lies mainly in indicating differences, as some STs may have the same melt profile. Changes in S. epidermidis epidemiology may warrant alterations in the inclusion of SNPs. We believe this method can reduce the threshold for performing genotyping analysis on an increasingly important nosocomial pathogen.
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http://dx.doi.org/10.1099/jmm.0.000663DOI Listing
February 2018

Fecal neutrophil gelatinase-associated lipocalin as a biomarker for inflammatory bowel disease.

J Gastroenterol Hepatol 2017 Jan;32(1):128-135

Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.

Background And Aim: Accurate, noninvasive biomarkers are needed to diagnose and monitor inflammatory bowel disease (IBD). Neutrophil gelatinase-associated lipocalin (NGAL), also known as lipocalin 2, is expressed in inflamed colonic epithelium and neutrophilic granulocytes. This study explores its properties as a biomarker in feces and plasma and, for the first time, compares fecal NGAL systematically with the existing fecal biomarker calprotectin.

Methods: Neutrophil gelatinase-associated lipocalin was measured in feces from 73 patients with IBD, 21 patients with infectious enterocolitis, 21 patients with irritable bowel syndrome, and 23 healthy subjects using ELISA. The results were correlated to calprotectin, clinical score, endoscopic score, and high-sensitive C-reactive protein. Plasma from 119 patients with IBD and 28 healthy controls was analyzed for NGAL.

Results: Fecal NGAL levels (median and interquartile range) were significantly elevated in active ulcerative colitis (UC) 6.05 (3.6-15.1) mg/kg and Crohn's disease (CD) 4.9 (1.5-7.7) mg/kg, compared with patients with inactive UC 1.3 (0.4-2.6) mg/kg, inactive CD 1.5 (0.5-1.7) mg/kg, irritable bowel syndrome 0.4 (0.2-0.6) mg/kg, and healthy controls (HC) 0.3 (0.1-0.4) mg/kg. Patients with infectious enterocolitis had significantly higher fecal-NGAL levels, 2.7 (1.4-5.6) mg/kg than HC. Sensitivity and specificity was 94.7% and 95.7%, respectively, for distinguishing between active IBD and HC. Stability of NGAL in stool was excellent for 7 days in room temperature. Plasma NGAL was significantly elevated in UC and CD compared with HC.

Conclusions: Fecal NGAL is a promising biomarker for IBD. As existing biomarkers are expressed mainly in granulocytes, NGAL's epithelial localization may give supplementary diagnostic information.
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http://dx.doi.org/10.1111/jgh.13598DOI Listing
January 2017

A Silenced vanA Gene Cluster on a Transferable Plasmid Caused an Outbreak of Vancomycin-Variable Enterococci.

Antimicrob Agents Chemother 2016 07 20;60(7):4119-27. Epub 2016 Jun 20.

Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø-The Arctic University of Norway, Tromsø, Norway Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North-Norway, Tromsø, Norway

We report an outbreak of vancomycin-variable vanA(+) enterococci (VVE) able to escape phenotypic detection by current guidelines and demonstrate the molecular mechanisms for in vivo switching into vancomycin resistance and horizontal spread of the vanA cluster. Forty-eight vanA(+) Enterococcus faecium isolates and one Enterococcus faecalis isolate were analyzed for clonality with pulsed-field gel electrophoresis (PFGE), and their vanA gene cluster compositions were assessed by PCR and whole-genome sequencing of six isolates. The susceptible VVE strains were cultivated in brain heart infusion broth containing vancomycin at 8 μg/ml for in vitro development of resistant VVE. The transcription profiles of susceptible VVE and their resistant revertants were assessed using quantitative reverse transcription-PCR. Plasmid content was analyzed with S1 nuclease PFGE and hybridizations. Conjugative transfer of vanA was assessed by filter mating. The only genetic difference between the vanA clusters of susceptible and resistant VVE was an ISL3-family element upstream of vanHAX, which silenced vanHAX gene transcription in susceptible VVE. Furthermore, the VVE had an insertion of IS1542 between orf2 and vanR that attenuated the expression of vanHAX Growth of susceptible VVE occurred after 24 to 72 h of exposure to vancomycin due to excision of the ISL3-family element. The vanA gene cluster was located on a transferable broad-host-range plasmid also detected in outbreak isolates with different pulsotypes, including one E. faecalis isolate. Horizontally transferable silenced vanA able to escape detection and revert into resistance during vancomycin therapy represents a new challenge in the clinic. Genotypic testing of invasive vancomycin-susceptible enterococci by vanA-PCR is advised.
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http://dx.doi.org/10.1128/AAC.00286-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914660PMC
July 2016

Development of a rapid and simplified protocol for direct bacterial identification from positive blood cultures by using matrix assisted laser desorption ionization time-of- flight mass spectrometry.

BMC Microbiol 2015 Nov 6;15:258. Epub 2015 Nov 6.

Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Olav Kyrres gate 17, 7006, Trondheim, Norway.

Background: Bloodstream infections represent serious conditions carrying a high mortality and morbidity rate. Rapid identification of microorganisms and prompt institution of adequate antimicrobial therapy is of utmost importance for a successful outcome. Aiming at the development of a rapid, simplified and efficient protocol, we developed and compared two in-house preparatory methods for the direct identification of bacteria from positive blood culture flasks (BD BACTEC FX system) by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF MS). Both methods employed saponin and distilled water for erythrocyte lysis. In method A the cellular pellet was overlaid with formic acid on the MALDI TOF target plate for protein extraction, whereas in method B the pellet was exposed to formic acid followed by acetonitrile prior to placing on the target plate.

Results: Best results were obtained by method A. Direct identification was achieved for 81.9 % and 65.8 % (50.3 % and 26.2 % with scores >2.0) of organisms by method A and method B, respectively. Overall concordance with final identification was 100 % to genus and 97.9 % to species level. By applying a lower cut-off score value, the levels of identification obtained by method A and method B increased to 89.3 % and 77.8 % of organisms (81.9 % and 65.8 % identified with scores >1.7), respectively. Using the lowered score criteria, concordance with final results was obtained for 99.3 % of genus and 96.6 % of species identifications.

Conclusion: The reliability of results, rapid performance (approximately 25 min) and applicability of in-house method A have contributed to implementation of this robust and cost-effective method in our laboratory.
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http://dx.doi.org/10.1186/s12866-015-0594-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636780PMC
November 2015

Comparative genomics to delineate pathogenic potential in non-O157 Shiga toxin-producing Escherichia coli (STEC) from patients with and without haemolytic uremic syndrome (HUS) in Norway.

PLoS One 2014 31;9(10):e111788. Epub 2014 Oct 31.

Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Medical Microbiology, St. Olavs University Hospital, Trondheim, Norway.

Shiga toxin-producing Escherichia coli (STEC) cause infections in humans ranging from asymptomatic carriage to bloody diarrhoea and haemolytic uremic syndrome (HUS). Here we present whole genome comparison of Norwegian non-O157 STEC strains with the aim to distinguish between strains with the potential to cause HUS and less virulent strains. Whole genome sequencing and comparisons were performed across 95 non-O157 STEC strains. Twenty-three of these were classified as HUS-associated, including strains from patients with HUS (n = 19) and persons with an epidemiological link to a HUS-case (n = 4). Genomic comparison revealed considerable heterogeneity in gene content across the 95 STEC strains. A clear difference in gene profile was observed between strains with and without the Locus of Enterocyte Effacement (LEE) pathogenicity island. Phylogenetic analysis of the core genome showed high degree of diversity among the STEC strains, but all HUS-associated STEC strains were distributed in two distinct clusters within phylogroup B1. However, non-HUS strains were also found in these clusters. A number of accessory genes were found to be significantly overrepresented among HUS-associated STEC, but none of them were unique to this group of strains, suggesting that different sets of genes may contribute to the pathogenic potential in different phylogenetic STEC lineages. In this study we were not able to clearly distinguish between HUS-associated and non-HUS non-O157 STEC by extensive genome comparisons. Our results indicate that STECs from different phylogenetic backgrounds have independently acquired virulence genes that determine pathogenic potential, and that the content of such genes is overlapping between HUS-associated and non-HUS strains.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111788PLOS
December 2015

The gastrin receptor antagonist netazepide (YF476) prevents oxyntic mucosal inflammation induced by Helicobacter pylori infection in Mongolian gerbils.

Helicobacter 2013 Dec 19;18(6):397-405. Epub 2013 Jul 19.

Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.

Objective: Long-term Helicobacter pylori infection causes gastritis leading to hypergastrinemia and predisposes to gastric cancer. Our aim was to assess the role of gastrin in oxyntic mucosal inflammation in H. pylori-infected Mongolian gerbils by means of the gastrin receptor antagonist netazepide (YF476).

Design: We studied 60 gerbils for 18 months and left five animals uninfected (control group), inoculated 55 with H. pylori, and treated 28 of the infected animals with netazepide (Hp+YF476 group). Twenty-seven infected animals were given no treatment (Hp group). We measured plasma gastrin and intraluminal pH. H. pylori detection and histologic evaluations of the stomach were carried out.

Results: All 55 inoculated animals were H. pylori positive at termination. Eighteen animals in the Hp group had gastritis. There was a threefold increase in mucosal thickness in the Hp group compared to the Hp+YF476 group, and a threefold increase in oxyntic neuroendocrine cells in the Hp group compared to the Hp+YF476 group (p < .05). All animals in the Hp+YF476 group had macro- and microscopically normal findings in the stomach. Plasma gastrin was higher in the Hp group than in the control group (172 ± 16 pmol/L vs 124 ± 5 pmol/L, p < .05) and highest in the Hp+YF476 group (530 ± 36 pmol/L). Intraluminal pH was higher in the Hp group than in the Hp+YF476 group (2.51 vs 2.30, p < .05).

Conclusion: The gastrin antagonist netazepide prevents H. pylori-induced gastritis in Mongolian gerbils. Thus, gastrin has a key role in the inflammatory reaction of the gastric mucosa to H. pylori infection in this species.
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http://dx.doi.org/10.1111/hel.12066DOI Listing
December 2013

Multiple-locus variant-repeat assay (MLVA) is a useful tool for molecular epidemiologic analysis of Streptococcus agalactiae strains causing bovine mastitis.

Vet Microbiol 2012 Jun 8;157(3-4):398-404. Epub 2012 Jan 8.

Norwegian University of Science and Technology, Department of Laboratory Medicine, Children's and Women's Health, Trondheim, Norway.

Group B streptococci (GBS) were considered a major cause of mastitis in cattle until preventive measures succeeded in controlling the disease in the 1970s and 1980s. During the last 5-6 years an increasing number of cases have been observed in some Scandinavian countries. A total of 187 GBS isolates from mastitis cases were collected from 119 animals in 34 Norwegian farms in the period from April 2007 to November 2010. 133 (71%) of the isolates were from farms with automated milking systems. The strains underwent typing of capsular polysaccharides (CPS) and surface proteins, and were analyzed by multi-locus variable repeat assay (MLVA) to investigate the epidemiological relationship of strains within and between farms. The GBS strains were differentiated into 12 types by CPS and surface protein analysis, with CPS types V (54%) and IV (34%) predominating. MLVA was superior to CPS and protein typing for strain differentiation, resolving the 187 strains into 37 types. In 29 of 34 farms all GBS strains had identical MLVA profiles specific for each farm. However, in one farm represented with 48 isolates, four MLVA variants with differences in one repeat locus were observed during the almost 3-year long collection period. Similar variations were observed at four other farms. This might reflect the stability of repeat loci under in vivo conditions. Farms with automated milking systems were overrepresented in this material. In conclusion, the five-loci MLVA allowed rapid high-resolution genotyping of the bovine GBS strains within and between farms.
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http://dx.doi.org/10.1016/j.vetmic.2011.12.034DOI Listing
June 2012

A comprehensive microbiological evaluation of fifty-four patients undergoing revision surgery due to prosthetic joint loosening.

J Med Microbiol 2012 Apr 1;61(Pt 4):572-581. Epub 2011 Dec 1.

Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.

The diagnosis of a chronic prosthetic joint infection (PJI) is challenging, and no consensus exists regarding how best to define the criteria required for microbiological identification. A general view is that culture of periprosthetic biopsies suffers from inadequate sensitivity. Recently, molecular analyses have been employed in some studies but the specificity of molecular analyses has been questioned, mainly due to contamination issues. In a prospective study of 54 patients undergoing revision surgery due to prosthetic joint loosening, we focused on two aspects of microbiological diagnosis of chronic PJI. First, by collecting diagnostic specimens in a highly standardized manner, we aimed at investigating the adequacy of various specimens by performing quantitative bacteriological culture. Second, we designed and performed real-time 16S rRNA gene PCR analysis with particular emphasis on minimizing the risk of false-positive PCR results. The specimens analysed included synovial fluid, periprosthetic biopsies from the joint capsule and the interface membrane, and specimens from the surface of the explanted prosthesis rendered accessible by scraping and sonication. No antibiotics were given prior to specimen collection. Based on five diagnostic criteria recently suggested, we identified 18 PJIs, all of which fulfilled the criterion of ≥2 positive cultures of periprosthetic specimens. The rate of culture-positive biopsies from the interface membrane was higher compared to specimens from the joint capsule and synovial fluid, and the interface membrane contained a higher bacterial load. Interpretational criteria were applied to differentiate a true-positive PCR from potential bacterial DNA contamination derived from the reagents used for DNA extraction and amplification. The strategy to minimize the risk of false-positive PCR results was successful as only two PCR results were false-positive out of 216 negative periprosthetic specimens. Although the PCR assays themselves were very sensitive, three patients with low bacterial numbers in periprosthetic specimens tested negative by real-time PCR. This overall lowered sensitivity is most likely due to the reduced specimen volume used for PCR analysis compared to culture and may also be due to interference from human DNA present in tissue specimens. According to the protocol in the present study, 16S rRNA gene real-time PCR did not identify more cases of septic prosthetic loosening than did culture of adequate periprosthetic biopsies.
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http://dx.doi.org/10.1099/jmm.0.036087-0DOI Listing
April 2012

Rapid multiple-locus variant-repeat assay (MLVA) for genotyping of Streptococcus agalactiae.

J Clin Microbiol 2010 Jul 26;48(7):2502-8. Epub 2010 May 26.

Norwegian University of Science and Technology, Department of Laboratory Medicine, Children's and Women's Health, Trondheim, Norway.

Several methods have been used for typing of Streptococcus agalactiae (group B streptococci [GBS]). Methods currently in use may provide inadequate resolution (e.g., typing of capsular polysaccharides and surface protein) or are labor-intensive and expensive (e.g., multilocus sequence typing [MLST] or pulsed-field gel electrophoresis). This work describes the construction and use of a multiple-locus variant-repeat assay (MLVA) on 126 well-characterized human GBS strains, consisting mostly of invasive Norwegian strains and international reference strains. Based on in silico whole-genomic analysis of the genomes of strains A909, NEM316, and 2603V/R, 18 candidate loci were selected and investigated by PCR. Eleven loci showed diversity, and the five most diverse loci were used for the construction of an MLVA, consisting of a multiplex PCR followed by fragment analysis with capillary electrophoresis. The assay generated clusters which corresponded well with those observed by other methods. However, it provided a considerably higher degree of diversity, with 70 different MLVA types compared to 36 types generated by MLST. Simpson's index of diversity for the 5-locus MLVA was 0.963, compared to 0.899 for the MLST in this strain collection. MLVA results will generally be available within 2 days, which is usually faster than MLST. In our hands, MLVA of GBS represents a rapid, easy, and comparably inexpensive method for high-resolution genotyping of GBS.
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http://dx.doi.org/10.1128/JCM.00234-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897478PMC
July 2010

Identification of surface proteins of group B streptococci: serotyping versus genotyping.

J Microbiol Methods 2009 Sep 30;78(3):363-5. Epub 2009 Jun 30.

Norwegian University of Science and Technology, Department of Laboratory Medicine, Children's and Women's Health, Trondheim, Norway.

We compared serotyping to genotyping of group B streptococcal (GBS) surface proteins in 147 Australasian isolates. Results were concordant for the two methods in 73.8% of 122 isolates, discordant for three and partially discordant for 29 isolates. For the purpose of epidemiological typing of GBS, genotyping is superior to serotyping.
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http://dx.doi.org/10.1016/j.mimet.2009.06.017DOI Listing
September 2009

Sonication is superior to scraping for retrieval of bacteria in biofilm on titanium and steel surfaces in vitro.

Acta Orthop 2009 Apr;80(2):245-50

Department of Orthopaedic Surgery, St Olav's University Hospital, Trondheim, Norway.

Background And Purpose: Low-virulence implant infections are characterized by bacterial colonization of the implant with subsequent biofilm formation. In these cases, soft tissue biopsies often prove to be culture negative. Consequently, detachment of the causative adherent bacteria is crucial for correct microbiological diagnosis. Using an in vitro model, we compared 4 methods of biofilm sampling from metal surfaces.

Methods: Discs of titanium and steel were incubated in the presence of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Propionibacterium acnes in Mueller Hinton broth. Non-adherent bacteria were removed by repeated rinsing of the discs. 10 parallels of each disc were subjected to 1 of 4 methods for bacterial recovery: (A) sonication of the discs, (B) scraping of the discs using surgical blades followed by streaking of the blades onto agar plates, (C) scraping of the discs followed by vortex mixing of the surgical blades, and (D) scraping of the discs followed by sonication of the surgical blades. Quantitative bacterial cultures were performed for each sampling method.

Results: With the exception of S. epidermidis on steel, sonication efficiently and reliably dislodged biofilm bacteria. The scraping methods employed did not detach bacteria embedded in biofilm.

Interpretation: Scraping of metal surfaces is not an adequate method for sampling of biofilm bacteria in vitro.
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http://dx.doi.org/10.3109/17453670902947457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823171PMC
April 2009

[Whipple's disease].

Tidsskr Nor Laegeforen 2008 Jun;128(12):1406-9

Gastroenterologisk seksjon Medisinsk avdeling.

Background: Whipple's disease is a rare infectious disease. This review describes the clinical picture, diagnostic aspects and treatment options.

Material And Methods: Based on a clinical case, a literature study was performed by searching PubMed (unlimited) with the words "whipples disease" combined with " TROPHERYMA WHIPPELII: " (118 hits) and " TROPHERYMA WHIPPLEI:" (65 hits). Titles and abstracts were used to identify other relevant articles.

Results And Interpretation: Whipple's disease may affect several organ systems and thus causes a wide range of symptoms. The most common ones are weight loss, abdominal pain, diarrhoea and arthralgia. The diagnosis is based on PAS-POSITIVE MATERIAL: in duodenal biopsies and identification of gene fragments from the bacterium TROPHERYMA WHIPPLEI:. Presence of the bacterium may be confirmed by sensitive polymerase chain reaction assays. Left without treatment the disease may be lethal. Proper antibiotic treatment is imperative to heal the disease.
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June 2008

Phylogenetic backgrounds and virulence profiles of atypical enteropathogenic Escherichia coli strains from a case-control study using multilocus sequence typing and DNA microarray analysis.

J Clin Microbiol 2008 Jul 7;46(7):2280-90. Epub 2008 May 7.

Department of Medical Microbiology, Children's and Women's Health, St Olavs University Hospital, Trondheim, Norway.

Atypical enteropathogenetic Escherichia coli (EPEC) strains are frequently detected in children with diarrhea but are also a common finding in healthy children. The aim of this study was to compare the phylogenetic ancestry and virulence characteristics of atypical (eae positive, stx and bfpA negative) EPEC strains from Norwegian children with (n = 37) or without (n = 19) diarrhea and to search for an association between phylogenetic ancestry and diarrhea. The strains were classified in phylogenetic groups by phylogenetic marker genes and in sequence types (STs) by multilocus sequence typing. Phylogenetic ancestry was compared to virulence characteristics based on DNA microarray analysis. Serotyping and pulsed-field gel electrophoresis (PFGE) were also performed. All four phylogenetic groups, 26 different STs, and 20 different clonal groups were represented among the 56 atypical EPEC strains. The strains were separated into three clusters by overall virulence gene profile; one large cluster with A, B1, and D strains and two clusters with group B2 strains. There was considerable heterogeneity in the PFGE profiles and serotypes, and almost half of the strains were O nontypeable. The efa1/lifA gene, previously shown to be statistically linked with diarrhea in this strain collection (J. E. Afset et al., J. Clin. Microbiol. 44:3703-3711, 2006), was present in 8 of 26 STs. The two phylogenetic groups B1 and D were weakly associated with diarrhea (P = 0.06 and P = 0.09, respectively). In contrast, group B2 was isolated most frequently from healthy controls (P = 0.05). In conclusion, the atypical EPEC strains were heterogeneous both phylogenetically and by virulence profile. Phylogenetic ancestry was less useful as a predictor of diarrhea than were specific virulence genes.
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http://dx.doi.org/10.1128/JCM.01752-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2446914PMC
July 2008

Antimicrobial susceptibility of invasive group B streptococcal isolates from south-west Sweden 1988-2001.

Scand J Infect Dis 2008 ;40(4):308-13

Department of Paediatrics, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Göteborg, Sweden.

The antibiotic susceptibility of 297 invasive isolates of group B streptococci (GBS) to a panel of 12 antibiotics was analysed using the E-test. The isolates (from 123 neonates and 174 adults) were collected from south-west Sweden during the 2 periods 1988-1997 and 1998-2001. The breakpoints of the Clinical and Laboratory Standards Institute were used. All isolates were sensitive to cefotaxime, meropenem, linezolid, vancomycin, moxifloxacin and quinupristin-dalfopristin. Two strains displayed a slightly decreased susceptibility to penicillin G (MIC 0.25 microg/ml) also when tested by the broth dilution method. Two per cent were resistant to erythromycin and 1% to clindamycin. Strains with intermediate sensitivity to erythromycin and clindamycin increased over the 2 study periods. 68% were resistant to doxycycline, and the resistance rate for doxycycline increased over the 2 study periods. No strain was resistant to trimethoprim-sulfamethoxazole. Serotype V dominated among strains with intermediate susceptibility to erythromycin and clindamycin. There were no other relationships between serotypes and decreased sensitivity to any agent. There were no significant differences in susceptibility to any agent tested between strains isolated from neonates and adults. In conclusion, penicillins remain the drug of choice in the region but with the increasing rates of intermediate susceptibility to both erythromycin and clindamycin, antibiotic sensitivity analysis should be performed on the GBS isolates from penicillin-allergic patients.
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http://dx.doi.org/10.1080/00365540701678702DOI Listing
September 2008

Real-time PCR targeting the sip gene for detection of group B Streptococcus colonization in pregnant women at delivery.

J Med Microbiol 2007 Feb;56(Pt 2):223-228

Department of Microbiology, St Olavs Hospital, N-7006 Trondheim, Norway.

Group B streptococcus (GBS) is an important aetiological agent of serious neonatal infections. A rapid and sensitive method for the detection of GBS colonization in pregnant women at delivery could make intrapartum screening for GBS possible. A real-time PCR method targeting the sip gene of GBS in pregnant women at delivery has been evaluated. The performance of the real-time PCR was compared with optimized GBS culture. Separate vaginal and rectal swabs were collected from women hospitalized at the delivery department at St Olavs Hospital, Trondheim, Norway, from January 15 through May 2005. The specimens were cultured on selective blood agar plates and in selective broth and examined by real-time PCR. Of samples from 251 women, 87 (34.7%) were GBS positive by culture and 86 (34.3%) were positive by PCR. Using GBS culture as the 'gold standard', the sensitivity of real-time PCR was 0.97 (95% confidence interval 0.90-0.99) and specificity was 0.99 (95% confidence interval 0.97-1.00). In two women the PCR was positive and the culture negative. Additional analysis using cylE PCR substantiates that these two women were true GBS carriers with negative GBS culture. The rate of GBS colonization was lower in vaginal specimens than in rectal specimens both by culture and PCR. The real-time PCR assay is fast, highly sensitive and specific for detecting GBS colonization in pregnant women at delivery, and has the potential for intrapartum detection of GBS colonization. Both vaginal and rectal samples are required to achieve highest possible detection rate.
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http://dx.doi.org/10.1099/jmm.0.46731-0DOI Listing
February 2007

Identification of virulence genes linked with diarrhea due to atypical enteropathogenic Escherichia coli by DNA microarray analysis and PCR.

J Clin Microbiol 2006 Oct;44(10):3703-11

Department of Medical Microbiology, St. Olavs University Hospital, N-7006 Trondheim, Norway.

The role of atypical enteropathogenic Escherichia coli (EPEC) in childhood diarrhea is controversial. The aim of the present study was to search for genes linked with diarrhea in atypical EPEC strains from a case-control study among Norwegian children. Using DNA microarray analysis, genomic DNAs from strains isolated from children with (n = 37) and without (n = 20) diarrhea were hybridized against 242 different oligonucleotide probes specific for 182 virulence genes or markers from all known E. coli pathotypes. PCR was performed to test the strains for seven putative virulence genes not included in the microarray panel. The OI-122 gene efa1/lifA was the gene with the strongest statistical association with diarrhea (P = 0.0008). Other OI-122 genes (set/ent, nleB, and nleE) and genes with other locations (lpfA, paa, ehxA, and ureD) were also associated with diarrheal disease. The phylogenetic marker gene yjaA was negatively associated with diarrhea (P = 0.0004). Atypical EPEC strains could be classified in two main virulence groups based on their content of OI-122, lpfA, and yjaA genes. Among children with diarrhea, atypical EPEC isolates belonging to virulence group I (OI-122 and lpfA positive, yjaA negative) were the most common, while the majority of isolates from healthy children were classified as virulence group II strains (OI-122 negative, lpfA and yjaA positive; P < 0.001). In conclusion, using DNA microarray analysis to determine the virulence gene profile of atypical EPEC isolates, several genes were found to be significantly associated with diarrhea. Based on their composition of virulence genes, the majority of strains could be classified in two virulence groups, of which one was seen mainly in children with diarrhea.
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http://dx.doi.org/10.1128/JCM.00429-06DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1594803PMC
October 2006

Identification and differentiation of Legionella pneumophila and Legionella spp. with real-time PCR targeting the 16S rRNA gene and species identification by mip sequencing.

Appl Environ Microbiol 2006 Sep;72(9):6394-8

Department of Medical Microbiology, Laboratory Center, St. Olavs Hospital, N-7006 Trondheim, Norway.

Fluorescent resonance energy transfer probes targeting the 16S rRNA gene were constructed for a sensitive and specific real-time PCR for identification and differentiation of Legionella pneumophila from other Legionella spp. For identification of non-L. pneumophila spp. by direct amplicon sequencing, two conventional PCR assays targeting the mip gene were established.
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http://dx.doi.org/10.1128/AEM.02839-05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563635PMC
September 2006

Internationally adopted children as a source for MRSA.

Euro Surveill 2005 Oct 20;10(10):E051020.5. Epub 2005 Oct 20.

Department of Medical Microbiology, St.Olavs University Hospital, Trondheim, Norway.

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http://dx.doi.org/10.2807/esw.10.42.02816-enDOI Listing
October 2005

Comparison of in vitro and in vivo complement activation by metal and bioabsorbable screws used in anterior cruciate ligament reconstruction.

Arthroscopy 2006 May;22(5):489-96

Department of Orthopaedics, Trondheim University Hospital, Institute of Immunology, Trondheim, Norway.

Purpose: The purpose of the study was to evaluate the biocompatibility of polylactide (PLLA) screws in comparison with standard metal screws for fixation of the patellar tendon graft in human anterior cruciate ligament (ACL) reconstruction.

Methods: A total of 41 patients (22 women and 19 men) were prospectively randomized for the use of metal interference screws (20 patients) or biologically resorbable PLLA screws from Linvatec, Largo, FL (21 patients). Average age at the time of surgery was 26 years (15 to 51 y). Synovial fluid and plasma were collected preoperatively and after 6 weeks in both groups. Plasma was analyzed for C5a and synovial fluid, as well as for terminal SC5b-9 complement complex (TCC) and interleukin (IL)-8. At 1 year after surgery, serum was incubated with metal, PLLA, and no screws; this was followed by analysis of C5a after 1 and 6 hours of incubation. Inflammatory mediators were measured through enzyme-linked immunosorbent assay (ELISA).

Results: In the BioScrew group, 4 patient samples showed high C5a concentration in synovial fluid after 6 weeks, but no statistically significant difference was observed between the 2 groups (P = .11). One patient in the BioScrew group had a high TCC value after 6 weeks, but no statistically significant difference was seen between the 2 groups (P = .20). In the in vitro study, no increased C5a generation was observed in sera incubated with a BioScrew or a metal screw compared with controls.

Conclusions: No statistically significant difference was observed between the BioScrew and metal screw groups concerning C5a, TCC, and IL-8 formation. However, some patients in the BioScrew group showed elevated values.

Level Of Evidence: Level II, prospective randomized trial.
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http://dx.doi.org/10.1016/j.arthro.2006.03.011DOI Listing
May 2006

[Tularaemia as a differential diagnosis in tumour colli].

Tidsskr Nor Laegeforen 2006 Apr;126(8):1055-7

Øre-nese-hals-avdelingen, St. Olavs Hospital. 7006 Trondheim.

Background: Tularaemia is a bacterial zoonosis caused by the bacterium Francisella tularensis. Different species of rodents and small mammals are the main reservoir; the transmission of disease is caused by direct contact with diseased animals, via insect vectors, or by ingestion of contaminated food and water. The disease is known to cause a complex clinical presentation in which head and neck manifestations are common. It occurs at a low annual rate in the northern and middle regions of Norway, but in recent years there have been several reported cases also in the southern parts of the country. The incidence of tularaemia is much higher in Sweden compared to Norway; the reason remains obscure.

Material And Methods: In this paper we report two admitted cases in which fever and a solitary neck mass were the predominant clinical findings. We review the number of cases reported to the Norwegian Institute of Public Health from 1976 to 2002, with particular emphasis on the role of tularaemia in the context of a neck tumour and oropharyngeal symptoms.

Results And Interpretation: The suspicion of tularaemia should be raised in patients with a solitary neck mass of presumed infectious aetiology, in particular when administration of beta-lactam antibiotics has failed. The diagnosis is usually dependent on serological evidence of F. tularensis infection. Recently, PCR techniques have been developed that facilitate rapid detection of F. tularensis in clinical specimens.
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April 2006

Cortical allograft as a vehicle for antibiotic delivery.

Acta Orthop 2005 Aug;76(4):481-6

Department of Orthopaedic Surgery, Norwegian University of Science and Technology, Trondheim.

Background: Infection can be a devastating complication after implantation of a cortical bone allograft. The allograft could act as a vehicle for local antibiotic prophylaxis.

Material And Methods: We studied the release of antibiotics in vitro from cortical bone allografts impregnated with antibiotics for different periods of time. We also studied whether cortical allografts impregnated with antibiotics could eradicate Staphylococcus aureus from an experimentally infected graft in vivo. In the in vitro study, pieces of cortical bone were impregnated with netilmicin, vancomycin, ciprofloxacin and rifampicin for 1 h, 10 h and 100 h. The antibiotics were eluted into phosphate-buffered saline (PBS) for 7 days, with daily transfer of the bone into fresh PBS. In the in vivo study, cortical allografts impregnated with antibiotics were placed in rats intramuscularly. 10 microL of an S. aureus suspension (0.6 x 10(5) CFU) was placed in the intramedullary cavity. After 15 days, the allografts were removed and examined for bacterial growth.

Results: The amount of antibiotics released in vitro was influenced by the time used for antibiotic impregnation of the bone. Allografts impregnated with netilmicin, vancomycin and rifampicin effectively eradicated perioperative contamination with S. aureus in vivo.

Interpretation: This study shows that a cortical bone allograft would be an effective vehicle for local antibiotic delivery.
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http://dx.doi.org/10.1080/17453670510041457DOI Listing
August 2005

Gastric juice: a barrier against infectious diseases.

Basic Clin Pharmacol Toxicol 2005 Feb;96(2):94-102

Department of Cancer Research and Molecular Medicine, Children's and Women's Health, Norwegian University of Science and Technology and University Hospital of Trondheim, Norway.

All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.
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http://dx.doi.org/10.1111/j.1742-7843.2005.pto960202.xDOI Listing
February 2005

Association of atypical enteropathogenic Escherichia coli (EPEC) with prolonged diarrhoea.

J Med Microbiol 2004 Nov;53(Pt 11):1137-1144

Laboratory of Medical Microbiology, St. Olavs Hospital, University Hospital and Department of Laboratory Medicine, Children's and Women's Health1 and Department of Public Health and General Practice, Faculty of Medicine,2 Norwegian University of Science and Technology, Trondheim, Norway.

The aim of the present case control study was to investigate the prevalence of atypical enteropathogenic Escherichia coli (EPEC) and its possible role in causing diarrhoea among children < 5 years of age in Norway. Stool specimens received in the laboratory from children with suspected gastroenteritis (n = 251) were, in addition to routine testing, analysed for the presence of EPEC by PCR of the eae, bfpA and stx genes. Specimens from healthy children (n = 210) recruited from Maternal and Child Health Centres were analysed for EPEC only. EPEC isolates (eae+, stx-) were classified as typical (bfpA+) or atypical (bfpA-), and were tested for O : K serogroup. Information on duration of diarrhoea was recorded in a questionnaire and from referral forms. Atypical EPEC was diagnosed in 37 patients (14.7 %) compared to 21 (10.0 %) of the healthy controls [Odds ratio (OR) = 1.4, P = 0.3]. Only three isolates, all from patients, belonged to EPEC serogroups. One patient had typical EPEC. Twenty (22.5 %) of 89 patients with diarrhoea lasting > or = 14 days had atypical EPEC. The association between atypical EPEC and prolonged diarrhoea (OR = 2.1, P = 0.04) was caused by a high prevalence among female patients (40.6 %). In conclusion, atypical EPEC was found to be slightly more prevalent in patients than controls, without any overall significant association with diarrhoea. However, a significant association was observed with diarrhoea lasting 14 days or more, a finding that may indicate a role for atypical EPEC in prolonged disease.
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http://dx.doi.org/10.1099/jmm.0.45719-0DOI Listing
November 2004

High local concentrations without systemic adverse effects after impaction of netilmicin-impregnated bone.

Acta Orthop Scand 2004 Jun;75(3):339-46

Department of Orthopedic Surgery, University Hospital, Trondheim, Norway.

Background: When cancellous bone is impregnated with antibiotics the subsequent release of antibiotics from the bone shows a high early release. Hence, impaction of large amounts of netilmicin-impregnated bone may cause toxic netilmicin values in serum.

Patients And Methods: We studied kidney and otovestibular function after impacting 50 g of netilmicin-impregnated cancellous bone during revision hip or knee arthroplasty in 20 patients. The bone was impacted in the acetabulum (n = 8), proximal femur (n = 9) and distal femur/proximal tibia (n = 3). Serum creatinine concentration was measured and audiometry was performed before and after the operation. Netilmicin concentrations in serum, joint fluid, and in urine were recorded postoperatively at regular intervals. We analyzed pharmacokinetics in two study groups receiving bone impregnated with netilmicin (50 mL), at either 50 mg netilmicin/mL (group I) or 100 mg netilmicin/mL (group II).

Results: Neither netilmicin-induced renal toxicity, nor otovestibular toxicity was registered. Peak serum netilmicin values in group I and group II were 0.9 (0.5-1.3) mg/L and 1.8 (0.6-4.0) mg/L, respectively (p = 0.04). Peak netilmicin concentrations in wound drainage fluid in group I and group II were 237 (9-647) mg/L and 561 (196-1132) mg/L, respectively (p = 0.01). In both groups, netilmicin was recovered in urine samples for approximately 4 weeks.

Interpretation: 50 grams of cancellous bone impregnated with 100 mg/mL netilmicin solution was impacted in the hip or knee joint with no adverse effects. Extremely high local concentrations of netilmicin in joint fluid were recorded postoperatively. The use of antibioitic-impregnated cancellous could be an option when performing revision of hip and knee prostheses.
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http://dx.doi.org/10.1080/00016470410001295DOI Listing
June 2004

Susceptibility to quinupristin-dalfopristin and linezolid in 839 clinical isolates of Gram-positive cocci from Norway.

Scand J Infect Dis 2004 ;36(4):254-8

Department of Microbiology, University of Tromsø, University Hospital of North Norway, Tromsø, Norway.

A total of 839 clinical isolates of Gram-positive cocci from Norway including Staphylococcus aureus (n = 214), coagulase negative Staphylococcus spp. (n = 100), Streptococcus pyogenes (n = 99), Streptococcus agalactiae (n = 80), Streptococcus pneumoniae (n = 127), Streptococcus spp. viridans group (n = 70), Enterococcus faecalis (n = 75), and Enterococcus faecium (n = 74), were tested by E-test for susceptibility to a range of antimicrobials including the novel antibiotics quinupristin-dalfopristin and linezolid. Subgroups of oxacillin resistant S. aureus and coagulase negative Staphylococcus spp., penicillin non-susceptible S. pneumoniae and vancomycin resistant Enterococcus spp. were specifically included as they are the intended targets for these new drugs. All isolates were susceptible to linezolid (MIC5o and MIC9o 0.25-2.0 mg/l, MIC range 0.12-2 mg/l). Staphylococcal and streptococcal isolates were also susceptible to quinupristin-dalfopristin except for some intermediately susceptible viridans group isolates (MIC54, and MIC90 0.25-2 mg/l, MIC range 0.125-2 mg/l). Enterococcus faecium (MIC90 = 4.0 mg/l) and Enterococcus faecalis (MIC50 = 8.0 mg/l, MIC90 > or = 32 mg/l) were less susceptible to this substance. There was no linkage between reduced susceptibility to linezolid or quinupristin-dalfopristin and resistance to other classes of antimicrobials. The study demonstrated a high prevalence of in vitro susceptibility to linezolid and quinupristin-dalfopristin, which is necessary for their use in the treatment of infections with resistant Gram-positive pathogens. The results were used to evaluate the appropriateness of breakpoints and to define a baseline for monitoring possible future emergence of resistance to quinupristin-dalfopristin and linezolid in Norway.
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http://dx.doi.org/10.1080/00365540410019570DOI Listing
July 2004

High prevalence of atypical enteropathogenic Escherichia coli (EPEC) in Norwegian children with diarrhoea.

J Med Microbiol 2003 Nov;52(Pt 11):1015-1019

Laboratory of Medical Microbiology, St Olav's Hospital, University Hospital, N-7006 Trondheim, Norway 2Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.

The aim of the present study was to investigate the relative contribution of enteropathogenic Escherichia coli (EPEC) as a cause of infectious diarrhoea in Norwegian children. Data from faecal specimens from children <2 years old with diarrhoea during the year 2001 were analysed. E. coli isolates with the attaching and effacing genotype (eae+) were examined for the presence of the bundle-forming pilus (bfpA) and Shiga toxin genes by PCR, and for genetic relatedness by PFGE. During the 1-year period, 598 specimens from 440 patients <2 years old were analysed. Potential enteric pathogens were identified in 124 patients (28.2 %). EPEC was the most frequently identified agent (44 patients), followed by rotavirus (41 patients), Campylobacter jejuni (17 patients) and adenovirus (17 patients). All other agents were detected in five patients or less. Only one of the eae+ E. coli isolates was classified as typical EPEC (bfpA+). Among the 43 isolates that were classified as atypical EPEC (bfpA-), eight strains belonged to EPEC serogroups, whereas the majority of strains (n = 35) were not agglutinated by EPEC antisera. None of the EPEC isolates were genetically related. This study demonstrates that atypical EPEC of non-EPEC serogroups is highly prevalent among Norwegian children with diarrhoea.
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http://dx.doi.org/10.1099/jmm.0.05287-0DOI Listing
November 2003
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