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Jensen SR, Mirsepasi-Lauridsen HC, Thysen AH, Brynskov J, Krogfelt KA, Petersen AM, Pedersen AE, Brix S. Distinct inflammatory and cytopathic characteristics of Escherichia coli isolates from inflammatory bowel disease patients. Int J Med Microbiol 2015; 305:925-36. [PMID: 26522075 DOI: 10.1016/j.ijmm.2015.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 09/07/2015] [Accepted: 10/11/2015] [Indexed: 12/26/2022] Open
Abstract
Escherichia coli (E. coli) may be implicated in the pathogenesis of inflammatory bowel disease (IBD), as implied from a higher prevalence of mucosa-associated E. coli in the gut of IBD-affected individuals. However, it is unclear whether different non-diarrheagenic E. coli spp. segregate from each other in their ability to promote intestinal inflammation. Herein we compared the inflammation-inducing properties of non-diarrheagenic LF82, 691-04A, E. coli Nissle 1917 (ECN) and eleven new intestinal isolates from different locations in five IBD patients and one healthy control. Viable E. coli were cultured with human monocyte-derived dendritic cells (moDCs) and monolayers of intestinal epithelial cells (IECs), followed by analysis of secreted cytokines, intracellular levels of reactive oxygen species and cellular death. The IBD-associated E. coli LF82 induced the same dose-dependent inflammatory cytokine profile as ECN and ten of the new E. coli isolates displayed as high level IL-12p70, IL-1β, IL-23 and TNF-α from moDCs irrespective of their site of isolation (ileum/colon/faeces), disease origin (diseased/non-diseased) or known virulence factors. Contrarily, 691-04A and one new IBD E. coli isolate induced a different cellular phenotype with enhanced killing of moDCs and IECs, coupled to elevated IL-18. The cytopathic nature of 691-04A and one other IBD E. coli isolate suggests that colonization with specific non-diarrheagenic E. coli could promote intestinal barrier leakage and profound intestinal inflammation, while LF82, ECN and the remaining non-diarrheagenic E. coli isolates hold notorious pro-inflammatory characteristics that can progress inflammation in case of intestinal barrier leakage.
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Clausen ML, Slotved HC, Krogfelt KA, Andersen PS, Agner T. In vivoexpression of antimicrobial peptides in atopic dermatitis. Exp Dermatol 2015; 25:3-9. [DOI: 10.1111/exd.12831] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2015] [Indexed: 12/13/2022]
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Frimodt-Møller J, Charbon G, Krogfelt KA, Løbner-Olesen A. Control regions for chromosome replication are conserved with respect to sequence and location among Escherichia coli strains. Front Microbiol 2015; 6:1011. [PMID: 26441936 PMCID: PMC4585315 DOI: 10.3389/fmicb.2015.01011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/07/2015] [Indexed: 12/14/2022] Open
Abstract
In Escherichia coli, chromosome replication is initiated from oriC by the DnaA initiator protein associated with ATP. Three non-coding regions contribute to the activity of DnaA. The datA locus is instrumental in conversion of DnaAATP to DnaAADP (datA dependent DnaAATP hydrolysis) whereas DnaA rejuvenation sequences 1 and 2 (DARS1 and DARS2) reactivate DnaAADP to DnaAATP. The structural organization of oriC, datA, DARS1, and DARS2 were found conserved among 59 fully sequenced E. coli genomes, with differences primarily in the non-functional spacer regions between key protein binding sites. The relative distances from oriC to datA, DARS1, and DARS2, respectively, was also conserved despite of large variations in genome size, suggesting that the gene dosage of either region is important for bacterial growth. Yet all three regions could be deleted alone or in combination without loss of viability. Competition experiments during balanced growth in rich medium and during mouse colonization indicated roles of datA, DARS1, and DARS2 for bacterial fitness although the relative contribution of each region differed between growth conditions. We suggest that this fitness advantage has contributed to conservation of both sequence and chromosomal location for datA, DARS1, and DARS2.
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Skindersoe ME, Rasmussen L, Andersen LP, Krogfelt KA. A Novel Assay for Easy and Rapid Quantification of Helicobacter pylori Adhesion. Helicobacter 2015; 20:199-205. [PMID: 25603836 DOI: 10.1111/hel.12191] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Reducing adhesion of Helicobacter pylori to gastric epithelial cells could be a new way to counteract infections with this organism. We here present a novel method for quantification of Helicobacter pylori adhesion to cells. METHODS Helicobacter pylori is allowed to adhere to AGS or MKN45g cells in a 96-well microtiter plate. Then wells are added saponin, which lyses the cells without affecting the bacteria. After addition of alamarBlue(®) (resazurin) and 1- to 2-hour incubation, fluorescence measurements can be used to quantify the number of adherent bacteria. RESULTS By use of the method, we demonstrate that adhesion of both a sabA and babA deletion mutant of H. pylori is significantly reduced compared to the wild type. CONCLUSION The method offers a number of applications and may be used to compare the adherence potential of different strains of H. pylori to either cells or different materials or to screen for potential anti-adhesive compounds. The results presented here suggest that this easy and reproducible assay is well suited for quantitative investigation of H. pylori adhesion.
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van Alphen LB, Ethelberg S, Villumsen S, Krogfelt KA. Trends in human leptospirosis in Denmark, 1980 to 2012. Euro Surveill 2015; 20:21054. [PMID: 25764192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
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van Alphen LB, Ethelberg S, Villumsen S, Krogfelt KA. Author’s reply: Trends in Human Leptospirosis in Denmark, 1980 to 2012. Euro Surveill 2015. [DOI: 10.2807/1560-7917.es2015.20.9.21054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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van Alphen LB, Lemcke Kunoe A, Ceper T, Kähler J, Kjelsø C, Ethelberg S, Krogfelt KA. Trends in Human Leptospirosis in Denmark, 1980 to 2012. Euro Surveill 2015. [DOI: 10.2807/1560-7917.es2015.20.4.21019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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van Alphen LB, Lemcke Kunoe A, Ceper T, Kahler J, Kjelso C, Ethelberg S, Krogfelt KA. Trends in human leptospirosis in Denmark, 1980 to 2012. Euro Surveill 2015; 20:21019. [PMID: 25655055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
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Kuhn KG, Emborg HD, Krogfelt KA, Mølbak K. Detecting non-typhoid Salmonella in humans by enzyme-linked immunosorbent assays (ELISAs): practical and epidemiological aspects. Methods Mol Biol 2015; 1225:117-126. [PMID: 25253252 DOI: 10.1007/978-1-4939-1625-2_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Salmonellosis caused by non-typhoid Salmonella serotypes is one of the most common causes of food-borne illness throughout the world. The diagnosis is primarily by culture and more recently molecular methods, whereas the use of serological methods for diagnosis of Salmonella infections is limited by high running costs as well as low sensitivity and specificity. Fast and reliable immunoassays for detection of S. typhi subunit antigens are commercially available, but there is no international consensus of similar tests for non-typhoid salmonellosis. Most immunoassays for non-typhoid human Salmonella diagnosis are developed in-house and used in-house for research or regional surveillance purposes. Only few laboratories use serology for the diagnosis of Salmonella-associated complications such as arthritis. Considering the current burden of disease, the development of a validated and standardized, commercially available antibody assay for diagnosing non-typhoid human salmonellosis can be of great benefit for diagnostic and surveillance purposes throughout the world.
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Zeddeman A, van Gent M, Heuvelman CJ, van der Heide HG, Bart MJ, Advani A, Hallander HO, Wirsing von Konig CH, Riffelman M, Storsaeter J, Vestrheim DF, Dalby T, Krogfelt KA, Fry NK, Barkoff AM, Mertsola J, He Q, Mooi F. Investigations into the emergence of pertactin-deficient Bordetella pertussis isolates in six European countries, 1996 to 2012. ACTA ACUST UNITED AC 2014; 19. [PMID: 25166348 DOI: 10.2807/1560-7917.es2014.19.33.20881] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pathogen adaptation has been proposed to contribute to the resurgence of pertussis. A striking recent example is the emergence of isolates deficient in the vaccine component pertactin (Prn). This study explores the emergence of such Prn-deficient isolates in six European countries. During 2007 to 2009, 0/83 isolates from the Netherlands, 0/18 from the United Kingdom, 0/17 Finland, 0/23 Denmark, 4/99 Sweden and 5/20 from Norway of the isolates collected were Prn-deficient. In the Netherlands and Sweden, respectively 4/146 and 1/8 were observed in a later period (2010–12). The Prn-deficient isolates were genetically diverse and different mutations were found to inactivate the prn gene. These are indications that Prn-deficiency is subject to positive selective pressure. We hypothesise that the switch from whole cell to acellular pertussis vaccines has affected the balance between ‘costs and benefits’ of Prn production by Bordetella pertussis to the extent that isolates that do not produce Prn are able to expand. The absence of Prn-deficient isolates in some countries may point to ways to prevent or delay the spread of Prn-deficient strains. In order to substantiate this hypothesis, trends in the European B. pertussis population should be monitored continuously.
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Mølbak K, Simonsen J, Jørgensen CS, Krogfelt KA, Falkenhorst G, Ethelberg S, Takkinen J, Emborg HD. Seroincidence of human infections with nontyphoid Salmonella compared with data from public health surveillance and food animals in 13 European countries. Clin Infect Dis 2014; 59:1599-606. [PMID: 25100865 DOI: 10.1093/cid/ciu627] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We developed a model that enabled a back-calculation of the annual salmonellosis seroincidence from measurements of Salmonella antibodies and applied this model to 9677 serum samples collected from populations in 13 European countries. We found a 10-fold difference in the seroincidence, which was lowest in Sweden (0.06 infections per person-year), Finland (0.07), and Denmark (0.08) and highest in Spain (0.61), followed by Poland (0.55). These numbers were not correlated with the reported national incidence of Salmonella infections in humans but were correlated with prevalence data of Salmonella in laying hens (P < .001), broilers (P < .001), and slaughter pigs (P = .03). Seroincidence also correlated with Swedish data on the country-specific risk of travel-associated Salmonella infections (P = .001). Estimates based on seroepidemiological methods are well suited to measure the force of transmission of Salmonella to human populations, in particular relevant for assessments where data include notifications from areas, states or countries with diverse characteristics of the Salmonella surveillance.
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Bisgaard H, Vissing NH, Carson CG, Bischoff AL, Følsgaard NV, Kreiner-Møller E, Chawes BLK, Stokholm J, Pedersen L, Bjarnadóttir E, Thysen AH, Nilsson E, Mortensen LJ, Olsen SF, Schjørring S, Krogfelt KA, Lauritzen L, Brix S, Bønnelykke K. Deep phenotyping of the unselected COPSAC2010 birth cohort study. Clin Exp Allergy 2014; 43:1384-94. [PMID: 24118234 PMCID: PMC4158856 DOI: 10.1111/cea.12213] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 07/19/2013] [Accepted: 09/04/2013] [Indexed: 01/05/2023]
Abstract
Background We hypothesize that perinatal exposures, in particular the human microbiome and maternal nutrition during pregnancy, interact with the genetic predisposition to cause an abnormal immune modulation in early life towards a trajectory to chronic inflammatory diseases such as asthma and others. Objective The aim of this study is to explore these interactions by conducting a longitudinal study in an unselected cohort of pregnant women and their offspring with emphasis on deep clinical phenotyping, exposure assessment, and biobanking. Exposure assessments focus on the human microbiome. Nutritional intervention during pregnancy in randomized controlled trials are included in the study to prevent disease and to be able to establish causal relationships. Methods Pregnant women from eastern Denmark were invited during 2008–2010 to a novel unselected ‘COPSAC2010’ cohort. The women visited the clinic during pregnancy weeks 24 and 36. Their children were followed at the clinic with deep phenotyping and collection of biological samples at nine regular visits until the age of 3 and at acute symptoms. Randomized controlled trials of high‐dose vitamin D and fish oil supplements were conducted during pregnancy, and a trial of azithromycin for acute lung symptoms was conducted in the children with recurrent wheeze. Results Seven hundred and thirty‐eight mothers were recruited from week 24 of gestation, and 700 of their children were included in the birth cohort. The cohort has an over‐representation of atopic parents. The participant satisfaction was high and the adherence equally high with 685 children (98%) attending the 1 year clinic visit and 667 children (95%) attending the 2 year clinic visit. Conclusions The COPSAC2010 birth cohort study provides longitudinal clinical follow‐up with highly specific end‐points, exposure assessments, and biobanking. The cohort has a high adherence rate promising strong data to elucidate the interaction between genomics and the exposome in perinatal life leading to lifestyle‐related chronic inflammatory disorders such as asthma.
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van der Plas MJA, Andersen AS, Nazir S, van Tilburg NH, Oestergaard PR, Krogfelt KA, van Dissel JT, Hensbergen PJ, Bertina RM, Nibbering PH. A novel serine protease secreted by medicinal maggots enhances plasminogen activator-induced fibrinolysis. PLoS One 2014; 9:e92096. [PMID: 24647546 PMCID: PMC3960166 DOI: 10.1371/journal.pone.0092096] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 02/19/2014] [Indexed: 11/23/2022] Open
Abstract
Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As haemostatic processes play an important role in wound healing, this study focused on the effects of maggot secretions on coagulation and fibrinolysis. The results showed that maggot secretions enhance plasminogen activator-induced formation of plasmin and fibrinolysis in a dose- and time-dependent manner. By contrast, coagulation was not affected by secretions. Biochemical studies indicated that a novel serine protease within secretions, designated Sericase, cleaved plasminogen to several fragments. Recombinant Sericase degraded plasminogen leading amongst others to the formation of the mini-plasminogen like fragment Val454-plasminogen. In addition, the presence of a non-proteolytic cofactor in secretions was discovered, which plays a role in the enhancement of plasminogen activator-induced fibrinolysis by Sericase. We conclude from our in vitro studies that the novel serine protease Sericase, with the aid of a non-proteolytic cofactor, enhances plasminogen activator-induced fibrinolysis.
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Adediran J, Leatham-Jensen MP, Mokszycki ME, Frimodt-Møller J, Krogfelt KA, Kazmierczak K, Kenney LJ, Conway T, Cohen PS. An Escherichia coli Nissle 1917 missense mutant colonizes the streptomycin-treated mouse intestine better than the wild type but is not a better probiotic. Infect Immun 2014; 82:670-82. [PMID: 24478082 PMCID: PMC3911375 DOI: 10.1128/iai.01149-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/18/2013] [Indexed: 01/08/2023] Open
Abstract
Previously we reported that the streptomycin-treated mouse intestine selected for two different Escherichia coli MG1655 mutants with improved colonizing ability: nonmotile E. coli MG1655 flhDC deletion mutants that grew 15% faster in vitro in mouse cecal mucus and motile E. coli MG1655 envZ missense mutants that grew slower in vitro in mouse cecal mucus yet were able to cocolonize with the faster-growing flhDC mutants. The E. coli MG1655 envZ gene encodes a histidine kinase that is a member of the envZ-ompR two-component signal transduction system, which regulates outer membrane protein profiles. In the present investigation, the envZP41L gene was transferred from the intestinally selected E. coli MG1655 mutant to E. coli Nissle 1917, a human probiotic strain used to treat gastrointestinal infections. Both the E. coli MG1655 and E. coli Nissle 1917 strains containing envZP41L produced more phosphorylated OmpR than their parents. The E. coli Nissle 1917 strain containing envZP41L also became more resistant to bile salts and colicin V and grew 50% slower in vitro in mucus and 15% to 30% slower on several sugars present in mucus, yet it was a 10-fold better colonizer than E. coli Nissle 1917. However, E. coli Nissle 1917 envZP41L was not better at preventing colonization by enterohemorrhagic E. coli EDL933. The data can be explained according to our "restaurant" hypothesis for commensal E. coli strains, i.e., that they colonize the intestine as sessile members of mixed biofilms, obtaining the sugars they need for growth locally, but compete for sugars with invading E. coli pathogens planktonically.
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Stokholm J, Schjørring S, Pedersen L, Bischoff AL, Følsgaard N, Carson CG, Chawes BLK, Bønnelykke K, Mølgaard A, Krogfelt KA, Bisgaard H. Prevalence and predictors of antibiotic administration during pregnancy and birth. PLoS One 2013; 8:e82932. [PMID: 24340068 PMCID: PMC3858309 DOI: 10.1371/journal.pone.0082932] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/29/2013] [Indexed: 12/04/2022] Open
Abstract
Background Antibiotic treatment during pregnancy and birth is very common. In this study, we describe the estimated prevalence of antibiotic administration during pregnancy and birth in the COPSAC2010 pregnancy cohort, and analyze dependence on social and lifestyle-related factors. Methods 706 pregnant women from the novel unselected Copenhagen Prospective Study on Asthma in Childhood (COPSAC2010) pregnancy cohort participated in this analysis. Detailed information on oral antibiotic prescriptions during pregnancy filled at the pharmacy was obtained and verified longitudinally. Information on intrapartum antibiotics, social, and lifestyle-factors was obtained by personal interviews. Results The prevalence of antibiotic use was 37% during pregnancy and 33% intrapartum. Lower maternal age at birth; adjusted odds ratio (aOR) 0.94, 95% CI, [0.90-0.98], p = 0.003 and maternal smoking; aOR 1.97, 95% CI, [1.07-3.63], p = 0.030 were associated with use of antibiotics for urinary tract infection during pregnancy. Maternal educational level (low vs. high), aOR 2.32, 95% CI, [1.24-4.35], p = 0.011, maternal asthma; aOR 1.99, 95% CI, [1.33-2.98], p < 0.001 and previous childbirth; aOR 1.80, 95% CI, [1.21-2.66], p = 0.004 were associated with use of antibiotics for respiratory tract infection during pregnancy. Lower gestational age; aOR 0.72, 95% CI, [0.61-0.85], p < 0.001, maternal smoking; aOR 2.84, 95% CI, [1.33-6.06], p = 0.007, and nulliparity; aOR 1.79, 95% CI, [1.06-3.02], p = 0.030 were associated with administration of intrapartum antibiotics in women giving birth vaginally. Conclusion Antibiotic administration during pregnancy and birth may be influenced by social and lifestyle-factors. Understanding such risk factors may guide preventive strategies in order to avoid unnecessary use of antibiotics.
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Falkenhorst G, Ceper TH, Strid MA, Mølbak K, Krogfelt KA. Serological follow-up after non-typhoid salmonella infection in humans using a mixed lipopolysaccharide ELISA. Int J Med Microbiol 2013; 303:533-8. [DOI: 10.1016/j.ijmm.2013.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/05/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022] Open
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Stokholm J, Schjørring S, Eskildsen CE, Pedersen L, Bischoff AL, Følsgaard N, Carson CG, Chawes BLK, Bønnelykke K, Mølgaard A, Jacobsson B, Krogfelt KA, Bisgaard H. Antibiotic use during pregnancy alters the commensal vaginal microbiota. Clin Microbiol Infect 2013; 20:629-35. [PMID: 24118384 DOI: 10.1111/1469-0691.12411] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/18/2013] [Accepted: 09/23/2013] [Indexed: 11/26/2022]
Abstract
Antibiotics may induce alterations in the commensal microbiota of the birth canal in pregnant women. Therefore, we studied the effect of antibiotic administration during pregnancy on commensal vaginal bacterial colonization at gestational week 36. Six hundred and sixty-eight pregnant women from the novel unselected Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010 ) pregnancy cohort participated in this analysis. Detailed information on oral antibiotic prescriptions during pregnancy filled at the pharmacy was obtained and verified prospectively. Vaginal samples were obtained at pregnancy week 36 and cultured for bacteria. Women who received oral antibiotics during any pregnancy trimester had an increased rate of colonization by Staphylococcus species in the vaginal samples as compared with samples obtained from women without any antibiotic treatment during pregnancy (adjusted OR 1.63, 95% CI 1.06-2.52, p 0.028). Oral antibiotic administration in the third trimester were also associated with increased colonization by Staphylococcus species (adjusted OR 1.98, 95% CI 1.04-3.76, p 0.037). These bacteriological changes were associated with urinary tract infection antibiotics. Women treated in the third trimester of pregnancy were more often colonized by Escherichia coli than women without antibiotic treatment in the third trimester (adjusted OR 1.91, 95% CI 1.04-3.52, p 0.038). This change was associated with respiratory tract infection (RTI) antibiotics. We did not observe any significant changes in vaginal Streptococcus agalactiae (group B streptoccocus) or Staphylococcus aureus colonization following antibiotic treatment in pregnancy. Antibiotic administration during pregnancy leads to alterations in the vaginal microbiological ecology prior to birth, with potential morbidity, and long-term effects on the early microbial colonization of the neonate.
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Obeng-Nkrumah N, Twum-Danso K, Krogfelt KA, Newman MJ. High levels of extended-spectrum beta-lactamases in a major teaching hospital in Ghana: the need for regular monitoring and evaluation of antibiotic resistance. Am J Trop Med Hyg 2013; 89:960-964. [PMID: 24043693 PMCID: PMC3820343 DOI: 10.4269/ajtmh.12-0642] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Infections with bacteria producing extended-spectrum beta-lactamases (ESBLs) are increasing across Africa. This study reports on ESBL-producing Enterobacteriaceae as significant causes of infections and antibiotic resistance at Korle-Bu Teaching Hospital in Accra, Ghana. Of 300 isolates examined, 49.3% produced ESBLs. The prevalence of ESBLs was significantly high among isolates from neonates (28 of 43, 65.1%; relative risk = 1.62, 95% confidence interval = 1.33–2.13, P = 0.002) and adult patients > 65 years of age (36 of 51, 70.5%; relative risk = 1.89, 95% confidence interval = 1.41–2.40, P = 0.001). A marked increase in minimum inhibitory concentrations of ESBL-positive species was noticed compared with those for the other strains. Using these concentrations, we found that 26 (17%) ESBL producers were resistant to two or more antibiotics (aminoglycosides, fluoroquinolones, sulfonamide, and carbapenems) whereas 5 (3.2%) non–ESBL producers were multidrug resistant. Regular ESBL detection and evaluation of antibiotic resistance may help reduce the spread of ESBLs and antibiotic resistance in Ghana.
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Yde Nielsen S, Mølbak K, Nybo Andersen AM, Brink Henriksen T, Kantsø B, Krogfelt KA, Hjøllund NH. Prevalence of Coxiella burnetii in women exposed to livestock animals, Denmark, 1996 to 2002. Euro Surveill 2013; 18. [PMID: 23870098 DOI: 10.2807/1560-7917.es2013.18.28.20528] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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Rasmussen JJ, Vegge CS, Frøkiær H, Howlett RM, Krogfelt KA, Kelly DJ, Ingmer H. Campylobacter jejuni carbon starvation protein A (CstA) is involved in peptide utilization, motility and agglutination, and has a role in stimulation of dendritic cells. J Med Microbiol 2013; 62:1135-1143. [PMID: 23682166 DOI: 10.1099/jmm.0.059345-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Campylobacter jejuni is the most frequent cause of severe gastroenteritis in the developed world. The major symptom of campylobacteriosis is inflammatory diarrhoea. The molecular mechanisms of this infection are poorly understood compared to those of less frequent disease-causing pathogens. In a previous study, we identified C. jejuni proteins that antibodies in human campylobacteriosis patients reacted with. One of the immunogenic proteins identified (Cj0917) displays homology to carbon starvation protein A (CstA) from Escherichia coli, where this protein is involved in the starvation response and peptide uptake. In contrast to many bacteria, C. jejuni relies on amino acids and organic acids for energy, but in vivo it is highly likely that peptides are also utilized, although their mechanisms of uptake are unknown. In this study, Biolog phenotype microarrays have been used to show that a ΔcstA mutant has a reduced ability to utilize a number of di- and tri-peptides as nitrogen sources. This phenotype was restored through genetic complementation, suggesting CstA is a peptide uptake system in C. jejuni. Furthermore, the ΔcstA mutant also displayed reduced motility and reduced agglutination compared to WT bacteria; these phenotypes were also restored through complementation. Murine dendritic cells exposed to UV-killed bacteria showed a reduced IL-12 production, but the same IL-10 response when encountering C. jejuni ΔcstA compared to the WT strain. The greater Th1 stimulation elicited by the WT as compared to ΔcstA mutant cells indicates an altered antigenic presentation on the surface, and thus an altered recognition of the mutant. Thus, we conclude that C. jejuni CstA is important not only for peptide utilization, but also it may influence host-pathogen interactions.
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Jakobsen H, Bojer MS, Marinus MG, Xu T, Struve C, Krogfelt KA, Løbner-Olesen A. The alkaloid compound harmane increases the lifespan of Caenorhabditis elegans during bacterial infection, by modulating the nematode's innate immune response. PLoS One 2013; 8:e60519. [PMID: 23544153 PMCID: PMC3609739 DOI: 10.1371/journal.pone.0060519] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/28/2013] [Indexed: 11/18/2022] Open
Abstract
The nematode Caenorhabditis elegans has in recent years been proven to be a powerful in vivo model for testing antimicrobial compounds. We report here that the alkaloid compound Harmane (2-methyl-β-carboline) increases the lifespan of nematodes infected with a human pathogen, the Shiga toxin-producing Escherichia coli O157:H7 strain EDL933 and several other bacterial pathogens. This was shown to be unrelated to the weak antibiotic effect of Harmane. Using GFP-expressing E. coli EDL933, we showed that Harmane does not lower the colonization burden in the nematodes. We also found that the expression of the putative immune effector gene F35E12.5 was up-regulated in response to Harmane treatment. This indicates that Harmane stimulates the innate immune response of the nematode; thereby increasing its lifespan during bacterial infection. Expression of F35E12.5 is predominantly regulated through the p38 MAPK pathway; however, intriguingly the lifespan extension resulting from Harmane was higher in p38 MAPK-deficient nematodes. This indicates that Harmane has a complex effect on the innate immune system of C. elegans. Harmane could therefore be a useful tool in the further research into C. elegans immunity. Since the innate immunity of C. elegans has a high degree of evolutionary conservation, drugs such as Harmane could also be possible alternatives to classic antibiotics. The C. elegans model could prove to be useful for selection and development of such drugs.
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Følsgaard NV, Schjørring S, Chawes BL, Rasmussen MA, Krogfelt KA, Brix S, Bisgaard H. Pathogenic bacteria colonizing the airways in asymptomatic neonates stimulates topical inflammatory mediator release. Am J Respir Crit Care Med 2013; 187:589-95. [PMID: 23370914 DOI: 10.1164/rccm.201207-1297oc] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
RATIONALE Bacterial colonization of neonatal airways with the pathogenic bacterial species, Moraxella catarrhalis, Streptococcus pneumoniae, and Haemophilus influenzae, is associated with later development of childhood asthma. OBJECTIVES To study a possible association between colonization with pathogenic bacterial strains and the immune signature of the upper airways in healthy neonates. METHODS A total of 20 cytokines and chemokines were quantified in vivo in the airway mucosal lining fluid of 662 neonates from the Copenhagen Prospective Study of Asthma in Childhood 2010 birth cohort. Colonization of the hypopharynx with M. catarrhalis, S. pneumoniae, H. influenzae, and Staphylococcus aureus was assessed simultaneously. The association between immune signatures and bacterial colonization or noncolonized controls was analyzed using conventional statistical methods supplemented by a multivariate approach for pattern identification. MEASUREMENTS AND MAIN RESULTS Colonization with M. catarrhalis and H. influenzae induced a mixed T helper cell (Th) type 1/Th2/Th17 response with high levels of IL-1β (M. catarrhalis, P = 2.2 × 10(-12); H. influenzae, P = 7.1 × 10(-10)), TNF-α (M. catarrhalis, P = 1.5 × 10(-9); H. influenzae, P = 5.9 × 10(-7)), and macrophage inflammatory protein-1β (M. catarrhalis, P = 1.6 × 10(-11); H. influenzae, P = 2.7 × 10(-7)). S. aureus colonization demonstrated a Th17-promoting profile with elevated IL-17 levels (P = 1.6 × 10(-24)). S. pneumoniae colonization was not significantly associated with any of the mediators. CONCLUSIONS M. catarrhalis and H. influenzae colonization of the airways of asymptomatic neonates is associated with an inflammatory immune response of the airway mucosa, which may result in chronic inflammation.
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Boll EJ, Nielsen LN, Krogfelt KA, Struve C. Novel screening assay for in vivo selection of Klebsiella pneumoniae genes promoting gastrointestinal colonisation. BMC Microbiol 2012; 12:201. [PMID: 22967317 PMCID: PMC3463446 DOI: 10.1186/1471-2180-12-201] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 09/06/2012] [Indexed: 11/30/2022] Open
Abstract
Background Klebsiella pneumoniae is an important opportunistic pathogen causing pneumonia, sepsis and urinary tract infections. Colonisation of the gastrointestinal (GI) tract is a key step in the development of infections; yet the specific factors important for K. pneumoniae to colonize and reside in the GI tract of the host are largely unknown. To identify K. pneumoniae genes promoting GI colonisation, a novel genomic-library-based approach was employed. Results Screening of a K. pneumoniae C3091 genomic library, expressed in E. coli strain EPI100, in a mouse model of GI colonisation led to the positive selection of five clones containing genes promoting persistent colonisation of the mouse GI tract. These included genes encoding the global response regulator ArcA; GalET of the galactose operon; and a cluster of two putative membrane-associated proteins of unknown function. Both ArcA and GalET are known to be involved in metabolic pathways in Klebsiella but may have additional biological actions beneficial to the pathogen. In support of this, GalET was found to confer decreased bile salt sensitivity to EPI100. Conclusions The present work establishes the use of genomic-library-based in vivo screening assays as a valuable tool for identification and characterization of virulence factors in K. pneumoniae and other bacterial pathogens.
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Falkenhorst G, Simonsen J, Ceper TH, van Pelt W, de Valk H, Sadkowska-Todys M, Zota L, Kuusi M, Jernberg C, Rota MC, van Duynhoven YTHP, Teunis PFM, Krogfelt KA, Mølbak K. Serological cross-sectional studies on salmonella incidence in eight European countries: no correlation with incidence of reported cases. BMC Public Health 2012; 12:523. [PMID: 22799896 PMCID: PMC3490876 DOI: 10.1186/1471-2458-12-523] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 07/02/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Published incidence rates of human salmonella infections are mostly based on numbers of stool culture-confirmed cases reported to public health surveillance. These cases constitute only a small fraction of all cases occurring in the community. The extent of underascertainment is influenced by health care seeking behaviour and sensitivity of surveillance systems, so that reported incidence rates from different countries are not comparable. We performed serological cross-sectional studies to compare infection risks in eight European countries independent of underascertainment. METHODS A total of 6,393 sera from adults in Denmark, Finland, France, Italy, Poland, Romania, Sweden, and The Netherlands were analysed, mostly from existing serum banks collected in the years 2003 to 2008. Immunoglobulin A (IgA), IgM, and IgG against salmonella lipopolysaccharides were measured by in-house mixed ELISA. We converted antibody concentrations to estimates of infection incidence ('sero-incidence') using a Bayesian backcalculation model, based on previously studied antibody decay profiles in persons with culture-confirmed salmonella infections. We compared sero-incidence with incidence of cases reported through routine public health surveillance and with published incidence estimates derived from infection risks in Swedish travellers to those countries. RESULTS Sero-incidence of salmonella infections ranged from 56 (95% credible interval 8-151) infections per 1,000 person-years in Finland to 547 (343-813) in Poland. Depending on country, sero-incidence was approximately 100 to 2,000 times higher than incidence of culture-confirmed cases reported through routine surveillance, with a trend for an inverse correlation. Sero-incidence was significantly correlated with incidence estimated from infection risks in Swedish travellers. CONCLUSIONS Sero-incidence estimation is a new method to estimate and compare the incidence of salmonella infections in human populations independent of surveillance artefacts. Our results confirm that comparison of reported incidence between countries can be grossly misleading, even within the European Union. Because sero-incidence includes asymptomatic infections, it is not a direct measure of burden of illness. But, pending further validation of this novel method, it may be a promising and cost-effective way to assess infection risks and to evaluate the effectiveness of salmonella control programmes across countries or over time.
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Kuhn KG, Falkenhorst G, Ceper T, Dalby T, Ethelberg S, Mølbak K, Krogfelt KA. Detection of antibodies to Campylobacter in humans using enzyme-linked immunosorbent assays: a review of the literature. Diagn Microbiol Infect Dis 2012; 74:113-8. [PMID: 22795964 DOI: 10.1016/j.diagmicrobio.2012.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/22/2012] [Accepted: 06/02/2012] [Indexed: 12/01/2022]
Abstract
Campylobacteriosis is the most common cause of bacterial foodborne illness in the European Union and the United States. Infection with Campylobacter spp. is frequently associated with different sequelae including neuropathies and reactive arthritis. Diagnosis is mainly by bacterial culturing which is time consuming, expensive, and not well suited for diagnosing sequelae or identifying infections from stool samples with nonviable bacteria. Serologic assays, in particular ELISAs, are well suited for this purpose, but, at present, there is no international consensus on antibody assays for human campylobacteriosis. In an extensive literature review, 19 studies validating such assays were identified of which 13 were more than 10 years old. We conclude that the best validated of these assays are developed and used in-house for research purposes rather than for routine diagnostics. Considering the burden of disease and potential long-term severity of Campylobacter infections, developing a standardized, commercially available antibody assay could be of great benefit for diagnostic and surveillance purposes worldwide.
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