Background: Reduced antimicrobial susceptibility is prevalent in the Bacteroides fragilis group A... more Background: Reduced antimicrobial susceptibility is prevalent in the Bacteroides fragilis group Approximately 4-10% of clinical B. fragilis isolates show reduced susceptibility towards meropenem. We ascertained the prevalence of antimicrobial resistance in Bacteroides fragilis group isolated from healthy children in Denmark, representing a relatively antibiotic 'naïve' population. Material/methods: Faecal samples from 174 children 0-6 years old were plated on Brucella blood agar supplemented with vancomycin (7.5 µg/ml) and kanamycin (100 µg/ml.), with colistin 150 ug tablets placed on the plates that were incubated for three days in anaerobic atmosphere. Up to three morphologically distinct colonies were identified by MALDI-TOF MS (Biotyper). If a score >=2 could not be achieved, 16S rRNA gene sequencing was performed. Isolates were screened for meropenem (MEM), piperacillin-tazobactam (TZP), metronidazole (MTZ) and clindamycin (CLI) susceptibility by disk diffusion (Luu et al ECCMID 2013). MIC determination was performed using E-test (biomerieux) or M.I.C.E (Oxoid) gradient strips and EUCAST breakpoints if disk diffusion zones were below 29, 23, 25 and 10 mm for MEM, TZP, MTZ and CLI respectively.
The transfer of molecular biology methods and concepts to environmental microbiology and microbia... more The transfer of molecular biology methods and concepts to environmental microbiology and microbial ecology has provided new insights into microbial complexity and activity in many different types of natural settings, and the rapidly expanding genomic databases have further accelerated the development. Comparative genomics, meta-genomes, techniques for in situ metabolic activity monitoring, and DNA chips for rapid identification of hundreds of species as well as for transcriptomic investigations are tools which have recently been added to those of fluorescent in situ hybridization (FISH) and reporter gene techniques. This chapter reviews the application of some of these in situ methods and tools in the context of mucosal colonization, after which one specific example—monitoring of quorum sensing-based cell-cell communication in colonized lungs of cystic fibrosis (CF) animal models. The first fluorescent protein to be useful as a tool for gene expression was the green fluorescent protein (GFP) from the jellyfish Aequorea victoria. The last 10 years of development of new molecular tools for microscopic investigations, along with the rapid development and dispersal of advanced fluorescence microscopy methods, have resulted in greatly improved techniques for studies of microbial performance in very complex settings, including those found in connection with both commensal and pathogenic bacteria in animals and even human patients.
Information on the kinetics of the serum antibody response to infection with Yersinia enterocolit... more Information on the kinetics of the serum antibody response to infection with Yersinia enterocolitica is essential to allow the estimation and comparison of seroconversion rates in a diversity of pools of cross-sectional serum antibody measurements. Data from 94 patients with acute enteritis caused by Yersinia infection were used. The follow-up period for the longitudinal study was 36 months, addressed by questionnaire. An indirect enzyme-linked immunosorbent assay method was adapted to determine the concentration of antibodies against Y. enterocolitica in human sera. A mathematical within-host model was used to describe the interaction between pathogen and immune system and the waning of immunity after clearing of the pathogen. All observed antibodies (IgG, IgM, IgA) reached peak levels shortly after infection and then decayed slowly indicating that the median levels decreased only little during the observation period. Estimated maximum peak antibody levels were highest in IgG. Seroresponse curves of all antibodies showed large individual variation between patients. There was no apparent pattern of variation with age, nor any notable difference between genders. Estimated half-times were very long for all antibodies, and their posterior distributions were highly skewed. IgA appeared to have the most persistent antibody response, compared with IgG and IgM. Median peak levels of all three antibodies were similar. There was no significance found between peak antibody levels and severity of symptoms of gastrointestinal infection and severity of joint pain. Our findings allow the use of cross-sectional serum antibody measurements as biomarkers, to estimate seroconversion rates. Such seroincidence estimates include asymptomatic seroconversions, thereby avoiding under-reporting, and allows the comparison of infection pressures among countries, independent of their healthcare and surveillance systems.
Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resist... more Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resistant healthcare-associated disease resulting in diarrhea and pseudomembranous colitis. The two cytotoxic proteins, toxin A (TcdA) and toxin B (TcdB) are the major virulence factor responsible for the disease symptoms. We examined time-dependent oxidative detoxification of TcdA and TcdB using different molar ratios of protein / Cu 2+ / H2O2. The MCO reaction in molar ratios of 1:60:1000 for protein / Cu 2+ / H2O2 at pH 4.5 resulted in a significant 6 log10 fold reduction in cytotoxicity after 120-min incubation at 37 ºC. Circular dichroism revealed that MCO-detoxified TcdA and TcdB had secondary and tertiary structural folds similar to the native proteins. The conservation of immunogenic epitopes of both proteins was tested using monoclonal antibodies in an ELISA, comparing our MCO-detoxification approach to a conventional formaldehyde-detoxification method. The oxidative detoxification of TcdA and TcdB led to an average 2-fold reduction in antibody binding relative to native proteins, whereas formaldehyde cross-linking resulted in 3-fold and 5-fold reductions, respectively. Finally, we show that mice immunized with a vaccine consisting of MCOdetoxified TcdA and TcdB were fully protected against disease symptoms and death following a C. difficile infection and elicited substantial serum IgG responses against both TcdA and TcdB. The results of this study present copper ion-catalyzed oxidative detoxification of toxic proteins as a method highly suitable for the rapid production of safe, immunogenic and irreversible toxoid antigens for future vaccine development and may have the potential for replacing cross-linking reagents like formaldehyde.
Introduction. Acute otitis media (AOM) is the most common bacterial infection in early childhood,... more Introduction. Acute otitis media (AOM) is the most common bacterial infection in early childhood, but the underlying mechanisms making some children more susceptible are poorly understood. Aim. To examine the associations between bacterial airway colonization in early life and the risk of AOM and tympanostomy tube insertion (TTI), and whether such associations are modulated by an insufficient local immune mediator response to bacterial colonization. Methodology. Bacterial cultures from hypopharyngeal samples were obtained at 1 week, 1 month and 3 months of age in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort comprising 700 children. Twenty immune mediators were quantified from airway mucosal lining fluid sampled at 1 month. AOM symptoms were registered in a daily diary until 3 years. Information on TTI in the first 3 years was obtained from national registers. Results. Children colonized with Streptococcus pneumoniae at 1 month of age had increased incidence of AOM [aIRR 2.43 (1.14–5.21)] and children colonized with Moraxella catarrhalis at 1 month or Haemophilus influenzae at 3 months had an increased risk of TTI [aHR 1.45 (1.00–2.10) and 1.73 (1.10–2.71)]. There were no associations between the local immune mediator response to colonization and risk of AOM or TTI. Conclusion. Pathogenic bacterial airway colonization in early life was found to be associated with an increased risk of otitis media, albeit not consistently. These associations were independent of the local immune response to colonization.
Premature birth, especially if born before week 32 of gestation, is associated with increased ris... more Premature birth, especially if born before week 32 of gestation, is associated with increased risk of neonatal morbidity and mortality. Prophylactic use of probiotics has been suggested to protect preterm infants via supporting a healthy gut microbiota (GM) development, but the suggested strains and doses vary between studies. In this study, we profiled the GM of 5, 10 and 30-day fecal samples from two cohorts of preterm neonates (born <30 weeks of gestation) recruited in the same neonatal intensive care unit. One cohort (n = 165) was recruited from September 2006 to January 2009 before probiotics were introduced in the clinic. The second cohort (n = 87) was recruited from May 2010 to October 2011 after introducing Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis ssp. lactis BB-12 supplementation policy. Through V3-V4 region 16S rRNA gene amplicon sequencing, a distinct increase of L. rhamnosus and B. animalis was found in the fecal samples of neonates supplemented with probiotics. During the first 30 days of life, the preterm GM went through similarly patterned progression of bacterial populations. Staphylococcus and Weissella dominated in early samples, but was gradually overtaken by Veillonella, Enterococcus and Enterobacteriaceae. Probiotic supplementation was associated with pronounced reduction of Weissella, Veillonella spp. and the opportunistic pathogen Klebsiella. Potential nosocomial pathogens Citrobacter and Chryseobacterium species also gradually phased out. In conclusion, probiotic supplementation to preterm neonates affected gut colonization by certain bacteria, but did not change the overall longitudinal bacterial progression in the neonatal period.
The casual relationship between H. pylori and gastroduodenal diseases, including chronic gastriti... more The casual relationship between H. pylori and gastroduodenal diseases, including chronic gastritis and peptic ulcer disease, is well established in children. 1-6 Primarily colonization and incident infection with H. pylori occurs most commonly in childhood, in industrialized and in developing countries. 7 Over the last decade, the prevalence of H. pylori in the developed world has steadily decreased. Interestingly, a decreased in the incidence was not reported in all studies, one of the
Bacteriophages constitute an important part of the human gut microbiota, but their impact on this... more Bacteriophages constitute an important part of the human gut microbiota, but their impact on this community is largely unknown. Here, we cultivate temperate phages produced by 900 E. coli strains isolated from 648 fecal samples from 1-year-old children and obtain coliphages directly from the viral fraction of the same fecal samples. We find that 63% of strains hosted phages, while 24% of the viromes contain phages targeting E. coli. 150 of these phages, half recovered from strain supernatants, half from virome (73% temperate and 27% virulent) were tested for their host range on 75 E. coli strains isolated from the same cohort. Temperate phages barely infected the gut strains, whereas virulent phages killed up to 68% of them. We conclude that in fecal samples from children, temperate coliphages dominate, while virulent ones have greater infectivity and broader host range, likely playing a role in gut microbiota dynamics.
The aim of this study was to evaluate the performance of an in-house ELISA for the diagnosis of L... more The aim of this study was to evaluate the performance of an in-house ELISA for the diagnosis of Legionnaires&amp;amp;#39; disease (LD) by detection of IgM and IgG antibodies against Legionella (L.) pneumophila serogroups (sg) 1, 3 and 6. The evaluation was done throughout a two-year period in a diagnostic routine laboratory. Furthermore, the sensitivity of four different methods, the in-house L. pneumophila antibody test (ELISA), the urinary antigen test (Binax® EIA), an in-house PCR and culture, both alone and in combination was evaluated. From 2008 to 2010, 12,158 serum samples from 10,503 patients were analysed. During the same period, 361 cases of laboratory-confirmed LD cases were recorded in Denmark, but of these only 113 had a serum sample examined. The positive predictive value of the in-house ELISA was calculated to be 12.8 and the negative predictive value was 99.6, using only the confirmed LD cases as true positives. The sensitivity of the in-house ELISA for the detection of IgM and IgG antibodies in the confirmed LD cases was 61% and 36%, respectively. By combining the two ELISA assays the sensitivity increased to 66%. The sensitivity of the Legionella urinary antigen test (Binax® EIA) was 63%, of the in-house PCR 87% and of culture 69%. When all the different methods were combined, a higher sensitivity was calculated--for in-house ELISA (IgM+IgG) and Binax® EIA 91%, in-house ELISA (IgM+IgG) and in-house PCR 93%, in-house ELISA (IgM+IgG) and culture 93%, Binax® EIA and in-house PCR 79%, Binax® EIA and culture 68% and in-house PCR and culture 94%. This study confirms that the detection of IgG and IgM antibodies by ELISA is an important diagnostic tool, also during the initial phase of the disease. Furthermore, we showed that LD in Denmark with or without serum samples collected exhibits the same age and sex distribution and epidemiology, as in the rest of Europe, i.e., mostly men are infected, infections are mostly community acquired, followed by infection from travelling abroad. Apart from patients with notified LD, the patients investigated by serology were evenly distributed in all age groups; there was only a slightly higher ratio of men tested for &amp;amp;quot;atypical pneumonia&amp;amp;quot; in the serology laboratory.
This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8-19... more This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8-19 months and assessed the effect of the probiotics Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis on the pneumococcal carriage during daycare enrolment. Potential risk factors of pneumococcal carriage were analysed and the carriage study was compared with registered invasive pneumococcal disease (IPD) data. This study is a part of the ProbiComp study, which was a double-blind, randomized controlled trial, including 290 children allocated to probiotics or placebo for 6 months and recruited during two autumn seasons (2014/2015). Pneumococci were identified by optochin sensitivity, bile solubility, α-hemolysis and/or capsular reaction. Serotyping was performed by latex agglutination kit and Quellung reaction. The carriage rate of S. pneumoniae was 26.0% at baseline and 67.4% at the end of intervention. No significant difference was observed between the placebo group and the probiotics group (p = 0.508). Children aged 8-19 months were carriers of non-pneumococcal vaccine serotypes causing IPD in children aged 0-4 years. However, serotypes causing most IPD cases in Danish elderly were either not found or found with low prevalence suggesting that children are not the main reservoir of those serotypes and other age groups need to be considered as carriers. Streptococcus pneumoniae can cause invasive pneumococcal disease (IPD) which worldwide is associated with high mortality and morbidity at all ages despite the use of effective vaccines 1. S. pneumoniae colonizes the epithelium of the nasopharynx and at least 92 different serotypes are known 2,3. S. pneumoniae can cause meningitis, otitis media, pneumonia, sinusitis and bacteremia primarily in young children and elderly 4. Carriage of S. pneumoniae is a prerequisite for developing IPD, and is most frequent in young children, who act as reservoirs 4. High carriage rate is associated with a high prevalence of respiratory infections 5 and it is believed that children transmit IPD serotypes to other age groups 6-8. However, transmission from adults to children is also observed 8. Potential risk factors of pneumococcal carriage include attending daycare, young age, having siblings in daycare, having siblings <5 years and genetic and environmental factors such as socioeconomic conditions and passive smoking 4,9,10. Daycare attendance is considered a major risk factor 9,11,12. The currently available vaccines protect against a limited number of the known serotypes 3. The 7-valent pneumococcal conjugate vaccine (PCV7) was included in the Danish Childhood Immunization Program in 2007 and was replaced by PCV13 in 2010 1. PCV7 includes serotype 4, 6B, 9V, 14, 18C, 19F, and 23F while PCV13 includes the PCV7-serotypes and additional serotypes 1, 3, 5, 6A, 7F, and 19A 1,7. PCV7 led to a significant reduction in IPD caused by PCV7-serotypes markedly among children aged <2 years 1,3,6,13 , but also a significant reduction in IPD cases and carriage of vaccine serotypes among older children and adults was seen, especially in the age group 65+ years 3,8. This phenomenon is known as herd protection 8. With the reduction of PCV-serotypes, an increase
Decreased levels of antimicrobial peptides (AMPs) in atopic dermatitis (AD) have previously been ... more Decreased levels of antimicrobial peptides (AMPs) in atopic dermatitis (AD) have previously been reported and have been linked to the increased susceptibility to skin infections found in AD patients. This study intents to identify AMPs: hBD-2, hBD-3, RNase7, psoriasin and LL-37 in AD patients and healthy controls, and determine concentrations in consecutive depths of the outer most skin layers. Tape stripping was used on lesional and non-lesional skin. From each skin site, 35 consecutive tape strips were collected and pooled in groups of 5. Commercially available ELISA kits were used to determine AMP concentration in stratum corneum samples. hBD-2, hBD-3, RNase7 and psoriasin were identified in stratum corneum samples. hBD-3-level was markedly higher in AD non-lesional skin compared to healthy controls, and a similar trend was observed for RNase7. Most AMPs were distributed evenly through 35 tape strips, implying a homogeneous distribution of antimicrobial defense in the outer most skin layers. The findings indicate that AD patients may not suffer from a general baseline deficiency in AMPs, and that the innate immune defense is present throughout the stratum corneum, both insights of importance for understanding the role of AMPs in AD. Atopic dermatitis (AD) is a common skin disease characterized by dysfunctional immunological response, skin barrier defects and frequent skin infections. It is a chronic, relapsing skin disease, affecting up to 20% of children and up to 10% of adults worldwide 1. A major problem in the management and treatment of AD is recurrent skin infections with Staphylococcus aureus 2 , resulting in repeated flares, sustained disease activity and frequent antibiotic treatment. This increased susceptibility to skin infections has been attributed to decreased levels of antimicrobial peptides (AMPs) 3. AMPs act as direct antimicrobial effector molecules, creating an important first line of defense in the skin, and possess broad antimicrobial activity 4. Furthermore, AMPs are essential immune mediators, linking the adaptive and innate immune response, regulating cytokine response, attracting immune cells as well as interacting with the skin microbiome 5-7. Multifaceted functions of AMPs are described, promoting immunity as well as participating in the pathogenesis of certain inflammatory diseases 8,9 , making them interesting targets for therapeutic development and treatment of inflammatory diseases. Until now most studies on AMPs in AD skin have identified AMPs in full thickness skin biopsies 3,10-13 and only few studies using skin washing fluid, and tape stripping technique have been presented 14-16. The aim of the present study was to determine the concentration of different AMPs in lesional and non-lesional AD skin, and in healthy control skin, using tape stripping technique and commercially available ELISA kits, with focus on stratum corneum, where the antimicrobial function is anticipated to be of greatest importance. Results Clinical characteristics. SCORAD for AD patients ranged from 7.7-61.5, with a median of 33.8 (25-75 th percentile = 18.28-44.18) (Table 1). TEWL (baseline) was significantly higher in AD non-lesional skin (median TEWL = 9.2, 25-75 th percentile = 6.95-12.6) compared to healthy control skin (median TEWL = 5.9, 25-75 th percentile = 5.2-6.85) p = 0.04. TEWL after tape stripping was measured, and resulted in a median increase in TEWL of 60.95 g/cm2/h (25-75 th percentile = 47.08-76.83). All participants showed a noticeably increase in
and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according ... more and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according to standardized recommendations for epidemiological typing of B. pertussis. There were 81 different PFGE profiles, five of which (BpSR3, BpSR5, BpSR10, BpSR11, and BpSR12) were observed in 61% of the 396 isolates and shown to be predominant in almost all countries. The major profile, BpSR11, showed a decreasing trend from 25% to 30% in 1998 to 2005 to 13% in 2007 to 2009, and there were increases in BpSR3 and BpSR10 from 0% and 8% to 21% and 22%, respectively. One difference between these profiles is that BpSR11 contains isolates harboring the fim3-2 allele and BpSR3 and BpSR10 contain isolates harboring the fim3-1 allele. The total proportion of the five predominant profiles increased from 44% in 1998 to 2001 to 63% in 2004 to 2005 to 70% in 2007 to 2009. In conclusion, common PFGE profiles were identified in B. pertussis populations circulating in European countries with different vaccination programs and different vaccine coverages. These prevalent isolates contain the novel pertussis toxin promoter ptxP3 allele. However, there is evidence for diversifying selection between ptxP3 strains characterized by distinct PFGE profiles. This work shows that, even within a relatively short time span of 10 years, successful isolates which spread through Europe and cause large shifts in B. pertussis populations may emerge.
Since 2012, have we in Denmark observed an increase of invasive pneumococcal infections (IPD) due... more Since 2012, have we in Denmark observed an increase of invasive pneumococcal infections (IPD) due to Streptococcus pneumoniae serotype 24F. We here present epidemiological data on 24F IPD cases, and characterization of 48 24F clinical isolates based on clonal relationship, antimicrobial resistance (AMR) determinants and virulence factors. IPD surveillance data from (1999-2016) were used to calculate the incidence and age-distribution of serotype 24F IPD and the effect of pneumococcal conjugated vaccines (PCV). Characterization of forty-eight 24F isolates (14.7% of all 24F isolates from the period) was based on whole-genome sequencing analysis (WGS). The IPD cases of serotype 24F showed a significant increase (p < 0.05) for all age groups after the PCV-13 introduction in 2010. The majority of tested 24F isolates consisted of two MLST types, i.e. the ST72 and the ST162. Serotype 24F IPD increased in Denmark after the PCV-13 introduction in parallel with an increase of the ST162 clone. The genotypic penicillin binding protein (PBP) profile agreed with the phenotypical penicillin susceptibility. The virulence genes lytA, ply, piaA, piaB, piaC, rspB and the cpsA/wzg were detected in all 24F isolates, while the pspA and zmpC genes were absent. Streptococcus pneumoniae is a ubiquitous bacterium present in the commensal bacterial community in the human nasopharynx. It is responsible for non-invasive infections as well as invasive pneumococcal disease (IPD) with high morbidity and mortality especially among young children and the elderly 1. The introduction of the pneumococcal conjugated vaccine (PCV) provided an effective protection against IPD in children. The first PCV on the global market was Prevenar 7 (PCV-7) (Pfizer Vaccines) in 2000 including seven different serotypes (4, 6B, 9V, 14, 18C, 19F and 23F), followed by the 10-valent pneumococcal-conjugate vaccine (PCV-10) (Synflorix, GlaxoSmithKline Biologicals) in 2009 including the serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F, and by the Prevenar 13 vaccine (PCV-13) (Pfizer Vaccines) in 2010 including the serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F and 23F 1. Besides the conjugate vaccines, a pneumococcal polysaccharide vaccine (PPV-23) (Pneumovax ® , Merck) based on purified capsular polysaccharides from 23 different serotypes, was introduced in 1996. The PPV-23 vaccine is recommended for patients older than 2 years of age and of high risk for IPD and for the 65+ years age group 2,3. With the introduction of PCV, a significant reduction of IPD cases caused by the included PCV serotypes was seen, but at the same time serotype replacement was observed, with the appearance of new pneumococcal serotypes not included in the vaccines 1. One of the non-PCV serotypes that has emerged in recent years is serotype 24F 4,5. The non-vaccine serotype 24F is responsible for many penicillin non-susceptible related IPD cases 6. Serotype 24F is also linked to erythromycin-clindamycin and tetracycline resistance and is one of the main serotypes that was recovered from young children with IPD between 2011 and 2012 in France 7. After the introduction of PCV13 in 2010 in France, serotype 24F, including other non-vaccine serotypes (10A, 12F and 15A), were responsible for approximately 39% of pneumococcal meningitis (PM) cases in children below 5 years of age from 2012 to 2014 8. During the last five years, a small increase of IPD cases with serotype 24F has been observed in Denmark 1. Because the serotype 24F is an emerging non-pneumococcal vaccine serotype, which to our knowledge is not a part of any pneumococcal vaccine or as part of planned future pneumococcal vaccine. Is it therefore essential Department of Bacteria, Parasites and fungi, Statens Serum institut, copenhagen, Denmark. correspondence and requests for materials should be addressed to H.-C.S.
Background Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we e... more Background Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we examined EM patients in Norwegian general practice to find the proportion exposed to tick-transmitted microorganisms other than Borrelia, and the impact of co-infection on the clinical manifestations and disease duration. Methods Skin biopsies from 139/188 EM patients were analyzed using PCR for Neoehrlichia mikurensis, Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Follow-up sera from 135/188 patients were analyzed for spotted fever group (SFG) Rickettsia, A. phagocytophilum and Babesia microti antibodies, and tested with PCR if positive. Day 0 sera from patients with fever (8/188) or EM duration of ≥ 21 days (69/188) were analyzed, using PCR, for A. phagocytophilum, Rickettsia spp., Babesia spp. and N. mikurensis. Day 14 sera were tested for TBEV IgG. Results We detected no microorganisms in the skin biopsies nor in the sera of patients with fever or prolonged EM duration. ...
Staphylococcus aureus is recognized as an important pathogen causing a wide spectrum of diseases.... more Staphylococcus aureus is recognized as an important pathogen causing a wide spectrum of diseases. Here we examined the antimicrobial effects of the lectin isolated from leaves of Schinus terebinthifolia Raddi (SteLL) against S. aureus using in vitro assays and an infection model based on Galleria mellonella larvae. The actions of SteLL on mice macrophages and S. aureus-infected macrophages were also evaluated. SteLL at 16 µg/mL (8 × MIC) increased cell mass and DNA content of S. aureus in relation to untreated bacteria, suggesting that SteLL impairs cell division. Unlike ciprofloxacin, SteLL did not induce the expression of recA, crucial for DNA repair through SOS response. The antimicrobial action of SteLL was partially inhibited by 50 mM N-acetylglucosamine. SteLL reduced staphyloxathin production and increased ciprofloxacin activity towards S. aureus. This lectin also improved the survival of G. mellonella larvae infected with S. aureus. Furthermore, SteLL induced the release of ...
Klebsiella pneumoniae is a common cause of sepsis and is particularly associated with healthcare-... more Klebsiella pneumoniae is a common cause of sepsis and is particularly associated with healthcare-associated infections. New strategies are needed to prevent or treat infections due to the emergence of multi-drug resistant K. pneumoniae. The goal of this study was to determine the diversity and distribution of O (lipopolysaccharide) and K (capsular polysaccharide) antigens on a large (>500) global collection of K. pneumoniae strains isolated from blood to inform vaccine development efforts. A total of 645
Background: Reduced antimicrobial susceptibility is prevalent in the Bacteroides fragilis group A... more Background: Reduced antimicrobial susceptibility is prevalent in the Bacteroides fragilis group Approximately 4-10% of clinical B. fragilis isolates show reduced susceptibility towards meropenem. We ascertained the prevalence of antimicrobial resistance in Bacteroides fragilis group isolated from healthy children in Denmark, representing a relatively antibiotic 'naïve' population. Material/methods: Faecal samples from 174 children 0-6 years old were plated on Brucella blood agar supplemented with vancomycin (7.5 µg/ml) and kanamycin (100 µg/ml.), with colistin 150 ug tablets placed on the plates that were incubated for three days in anaerobic atmosphere. Up to three morphologically distinct colonies were identified by MALDI-TOF MS (Biotyper). If a score >=2 could not be achieved, 16S rRNA gene sequencing was performed. Isolates were screened for meropenem (MEM), piperacillin-tazobactam (TZP), metronidazole (MTZ) and clindamycin (CLI) susceptibility by disk diffusion (Luu et al ECCMID 2013). MIC determination was performed using E-test (biomerieux) or M.I.C.E (Oxoid) gradient strips and EUCAST breakpoints if disk diffusion zones were below 29, 23, 25 and 10 mm for MEM, TZP, MTZ and CLI respectively.
The transfer of molecular biology methods and concepts to environmental microbiology and microbia... more The transfer of molecular biology methods and concepts to environmental microbiology and microbial ecology has provided new insights into microbial complexity and activity in many different types of natural settings, and the rapidly expanding genomic databases have further accelerated the development. Comparative genomics, meta-genomes, techniques for in situ metabolic activity monitoring, and DNA chips for rapid identification of hundreds of species as well as for transcriptomic investigations are tools which have recently been added to those of fluorescent in situ hybridization (FISH) and reporter gene techniques. This chapter reviews the application of some of these in situ methods and tools in the context of mucosal colonization, after which one specific example—monitoring of quorum sensing-based cell-cell communication in colonized lungs of cystic fibrosis (CF) animal models. The first fluorescent protein to be useful as a tool for gene expression was the green fluorescent protein (GFP) from the jellyfish Aequorea victoria. The last 10 years of development of new molecular tools for microscopic investigations, along with the rapid development and dispersal of advanced fluorescence microscopy methods, have resulted in greatly improved techniques for studies of microbial performance in very complex settings, including those found in connection with both commensal and pathogenic bacteria in animals and even human patients.
Information on the kinetics of the serum antibody response to infection with Yersinia enterocolit... more Information on the kinetics of the serum antibody response to infection with Yersinia enterocolitica is essential to allow the estimation and comparison of seroconversion rates in a diversity of pools of cross-sectional serum antibody measurements. Data from 94 patients with acute enteritis caused by Yersinia infection were used. The follow-up period for the longitudinal study was 36 months, addressed by questionnaire. An indirect enzyme-linked immunosorbent assay method was adapted to determine the concentration of antibodies against Y. enterocolitica in human sera. A mathematical within-host model was used to describe the interaction between pathogen and immune system and the waning of immunity after clearing of the pathogen. All observed antibodies (IgG, IgM, IgA) reached peak levels shortly after infection and then decayed slowly indicating that the median levels decreased only little during the observation period. Estimated maximum peak antibody levels were highest in IgG. Seroresponse curves of all antibodies showed large individual variation between patients. There was no apparent pattern of variation with age, nor any notable difference between genders. Estimated half-times were very long for all antibodies, and their posterior distributions were highly skewed. IgA appeared to have the most persistent antibody response, compared with IgG and IgM. Median peak levels of all three antibodies were similar. There was no significance found between peak antibody levels and severity of symptoms of gastrointestinal infection and severity of joint pain. Our findings allow the use of cross-sectional serum antibody measurements as biomarkers, to estimate seroconversion rates. Such seroincidence estimates include asymptomatic seroconversions, thereby avoiding under-reporting, and allows the comparison of infection pressures among countries, independent of their healthcare and surveillance systems.
Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resist... more Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resistant healthcare-associated disease resulting in diarrhea and pseudomembranous colitis. The two cytotoxic proteins, toxin A (TcdA) and toxin B (TcdB) are the major virulence factor responsible for the disease symptoms. We examined time-dependent oxidative detoxification of TcdA and TcdB using different molar ratios of protein / Cu 2+ / H2O2. The MCO reaction in molar ratios of 1:60:1000 for protein / Cu 2+ / H2O2 at pH 4.5 resulted in a significant 6 log10 fold reduction in cytotoxicity after 120-min incubation at 37 ºC. Circular dichroism revealed that MCO-detoxified TcdA and TcdB had secondary and tertiary structural folds similar to the native proteins. The conservation of immunogenic epitopes of both proteins was tested using monoclonal antibodies in an ELISA, comparing our MCO-detoxification approach to a conventional formaldehyde-detoxification method. The oxidative detoxification of TcdA and TcdB led to an average 2-fold reduction in antibody binding relative to native proteins, whereas formaldehyde cross-linking resulted in 3-fold and 5-fold reductions, respectively. Finally, we show that mice immunized with a vaccine consisting of MCOdetoxified TcdA and TcdB were fully protected against disease symptoms and death following a C. difficile infection and elicited substantial serum IgG responses against both TcdA and TcdB. The results of this study present copper ion-catalyzed oxidative detoxification of toxic proteins as a method highly suitable for the rapid production of safe, immunogenic and irreversible toxoid antigens for future vaccine development and may have the potential for replacing cross-linking reagents like formaldehyde.
Introduction. Acute otitis media (AOM) is the most common bacterial infection in early childhood,... more Introduction. Acute otitis media (AOM) is the most common bacterial infection in early childhood, but the underlying mechanisms making some children more susceptible are poorly understood. Aim. To examine the associations between bacterial airway colonization in early life and the risk of AOM and tympanostomy tube insertion (TTI), and whether such associations are modulated by an insufficient local immune mediator response to bacterial colonization. Methodology. Bacterial cultures from hypopharyngeal samples were obtained at 1 week, 1 month and 3 months of age in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort comprising 700 children. Twenty immune mediators were quantified from airway mucosal lining fluid sampled at 1 month. AOM symptoms were registered in a daily diary until 3 years. Information on TTI in the first 3 years was obtained from national registers. Results. Children colonized with Streptococcus pneumoniae at 1 month of age had increased incidence of AOM [aIRR 2.43 (1.14–5.21)] and children colonized with Moraxella catarrhalis at 1 month or Haemophilus influenzae at 3 months had an increased risk of TTI [aHR 1.45 (1.00–2.10) and 1.73 (1.10–2.71)]. There were no associations between the local immune mediator response to colonization and risk of AOM or TTI. Conclusion. Pathogenic bacterial airway colonization in early life was found to be associated with an increased risk of otitis media, albeit not consistently. These associations were independent of the local immune response to colonization.
Premature birth, especially if born before week 32 of gestation, is associated with increased ris... more Premature birth, especially if born before week 32 of gestation, is associated with increased risk of neonatal morbidity and mortality. Prophylactic use of probiotics has been suggested to protect preterm infants via supporting a healthy gut microbiota (GM) development, but the suggested strains and doses vary between studies. In this study, we profiled the GM of 5, 10 and 30-day fecal samples from two cohorts of preterm neonates (born <30 weeks of gestation) recruited in the same neonatal intensive care unit. One cohort (n = 165) was recruited from September 2006 to January 2009 before probiotics were introduced in the clinic. The second cohort (n = 87) was recruited from May 2010 to October 2011 after introducing Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis ssp. lactis BB-12 supplementation policy. Through V3-V4 region 16S rRNA gene amplicon sequencing, a distinct increase of L. rhamnosus and B. animalis was found in the fecal samples of neonates supplemented with probiotics. During the first 30 days of life, the preterm GM went through similarly patterned progression of bacterial populations. Staphylococcus and Weissella dominated in early samples, but was gradually overtaken by Veillonella, Enterococcus and Enterobacteriaceae. Probiotic supplementation was associated with pronounced reduction of Weissella, Veillonella spp. and the opportunistic pathogen Klebsiella. Potential nosocomial pathogens Citrobacter and Chryseobacterium species also gradually phased out. In conclusion, probiotic supplementation to preterm neonates affected gut colonization by certain bacteria, but did not change the overall longitudinal bacterial progression in the neonatal period.
The casual relationship between H. pylori and gastroduodenal diseases, including chronic gastriti... more The casual relationship between H. pylori and gastroduodenal diseases, including chronic gastritis and peptic ulcer disease, is well established in children. 1-6 Primarily colonization and incident infection with H. pylori occurs most commonly in childhood, in industrialized and in developing countries. 7 Over the last decade, the prevalence of H. pylori in the developed world has steadily decreased. Interestingly, a decreased in the incidence was not reported in all studies, one of the
Bacteriophages constitute an important part of the human gut microbiota, but their impact on this... more Bacteriophages constitute an important part of the human gut microbiota, but their impact on this community is largely unknown. Here, we cultivate temperate phages produced by 900 E. coli strains isolated from 648 fecal samples from 1-year-old children and obtain coliphages directly from the viral fraction of the same fecal samples. We find that 63% of strains hosted phages, while 24% of the viromes contain phages targeting E. coli. 150 of these phages, half recovered from strain supernatants, half from virome (73% temperate and 27% virulent) were tested for their host range on 75 E. coli strains isolated from the same cohort. Temperate phages barely infected the gut strains, whereas virulent phages killed up to 68% of them. We conclude that in fecal samples from children, temperate coliphages dominate, while virulent ones have greater infectivity and broader host range, likely playing a role in gut microbiota dynamics.
The aim of this study was to evaluate the performance of an in-house ELISA for the diagnosis of L... more The aim of this study was to evaluate the performance of an in-house ELISA for the diagnosis of Legionnaires&amp;amp;#39; disease (LD) by detection of IgM and IgG antibodies against Legionella (L.) pneumophila serogroups (sg) 1, 3 and 6. The evaluation was done throughout a two-year period in a diagnostic routine laboratory. Furthermore, the sensitivity of four different methods, the in-house L. pneumophila antibody test (ELISA), the urinary antigen test (Binax® EIA), an in-house PCR and culture, both alone and in combination was evaluated. From 2008 to 2010, 12,158 serum samples from 10,503 patients were analysed. During the same period, 361 cases of laboratory-confirmed LD cases were recorded in Denmark, but of these only 113 had a serum sample examined. The positive predictive value of the in-house ELISA was calculated to be 12.8 and the negative predictive value was 99.6, using only the confirmed LD cases as true positives. The sensitivity of the in-house ELISA for the detection of IgM and IgG antibodies in the confirmed LD cases was 61% and 36%, respectively. By combining the two ELISA assays the sensitivity increased to 66%. The sensitivity of the Legionella urinary antigen test (Binax® EIA) was 63%, of the in-house PCR 87% and of culture 69%. When all the different methods were combined, a higher sensitivity was calculated--for in-house ELISA (IgM+IgG) and Binax® EIA 91%, in-house ELISA (IgM+IgG) and in-house PCR 93%, in-house ELISA (IgM+IgG) and culture 93%, Binax® EIA and in-house PCR 79%, Binax® EIA and culture 68% and in-house PCR and culture 94%. This study confirms that the detection of IgG and IgM antibodies by ELISA is an important diagnostic tool, also during the initial phase of the disease. Furthermore, we showed that LD in Denmark with or without serum samples collected exhibits the same age and sex distribution and epidemiology, as in the rest of Europe, i.e., mostly men are infected, infections are mostly community acquired, followed by infection from travelling abroad. Apart from patients with notified LD, the patients investigated by serology were evenly distributed in all age groups; there was only a slightly higher ratio of men tested for &amp;amp;quot;atypical pneumonia&amp;amp;quot; in the serology laboratory.
This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8-19... more This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8-19 months and assessed the effect of the probiotics Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis on the pneumococcal carriage during daycare enrolment. Potential risk factors of pneumococcal carriage were analysed and the carriage study was compared with registered invasive pneumococcal disease (IPD) data. This study is a part of the ProbiComp study, which was a double-blind, randomized controlled trial, including 290 children allocated to probiotics or placebo for 6 months and recruited during two autumn seasons (2014/2015). Pneumococci were identified by optochin sensitivity, bile solubility, α-hemolysis and/or capsular reaction. Serotyping was performed by latex agglutination kit and Quellung reaction. The carriage rate of S. pneumoniae was 26.0% at baseline and 67.4% at the end of intervention. No significant difference was observed between the placebo group and the probiotics group (p = 0.508). Children aged 8-19 months were carriers of non-pneumococcal vaccine serotypes causing IPD in children aged 0-4 years. However, serotypes causing most IPD cases in Danish elderly were either not found or found with low prevalence suggesting that children are not the main reservoir of those serotypes and other age groups need to be considered as carriers. Streptococcus pneumoniae can cause invasive pneumococcal disease (IPD) which worldwide is associated with high mortality and morbidity at all ages despite the use of effective vaccines 1. S. pneumoniae colonizes the epithelium of the nasopharynx and at least 92 different serotypes are known 2,3. S. pneumoniae can cause meningitis, otitis media, pneumonia, sinusitis and bacteremia primarily in young children and elderly 4. Carriage of S. pneumoniae is a prerequisite for developing IPD, and is most frequent in young children, who act as reservoirs 4. High carriage rate is associated with a high prevalence of respiratory infections 5 and it is believed that children transmit IPD serotypes to other age groups 6-8. However, transmission from adults to children is also observed 8. Potential risk factors of pneumococcal carriage include attending daycare, young age, having siblings in daycare, having siblings <5 years and genetic and environmental factors such as socioeconomic conditions and passive smoking 4,9,10. Daycare attendance is considered a major risk factor 9,11,12. The currently available vaccines protect against a limited number of the known serotypes 3. The 7-valent pneumococcal conjugate vaccine (PCV7) was included in the Danish Childhood Immunization Program in 2007 and was replaced by PCV13 in 2010 1. PCV7 includes serotype 4, 6B, 9V, 14, 18C, 19F, and 23F while PCV13 includes the PCV7-serotypes and additional serotypes 1, 3, 5, 6A, 7F, and 19A 1,7. PCV7 led to a significant reduction in IPD caused by PCV7-serotypes markedly among children aged <2 years 1,3,6,13 , but also a significant reduction in IPD cases and carriage of vaccine serotypes among older children and adults was seen, especially in the age group 65+ years 3,8. This phenomenon is known as herd protection 8. With the reduction of PCV-serotypes, an increase
Decreased levels of antimicrobial peptides (AMPs) in atopic dermatitis (AD) have previously been ... more Decreased levels of antimicrobial peptides (AMPs) in atopic dermatitis (AD) have previously been reported and have been linked to the increased susceptibility to skin infections found in AD patients. This study intents to identify AMPs: hBD-2, hBD-3, RNase7, psoriasin and LL-37 in AD patients and healthy controls, and determine concentrations in consecutive depths of the outer most skin layers. Tape stripping was used on lesional and non-lesional skin. From each skin site, 35 consecutive tape strips were collected and pooled in groups of 5. Commercially available ELISA kits were used to determine AMP concentration in stratum corneum samples. hBD-2, hBD-3, RNase7 and psoriasin were identified in stratum corneum samples. hBD-3-level was markedly higher in AD non-lesional skin compared to healthy controls, and a similar trend was observed for RNase7. Most AMPs were distributed evenly through 35 tape strips, implying a homogeneous distribution of antimicrobial defense in the outer most skin layers. The findings indicate that AD patients may not suffer from a general baseline deficiency in AMPs, and that the innate immune defense is present throughout the stratum corneum, both insights of importance for understanding the role of AMPs in AD. Atopic dermatitis (AD) is a common skin disease characterized by dysfunctional immunological response, skin barrier defects and frequent skin infections. It is a chronic, relapsing skin disease, affecting up to 20% of children and up to 10% of adults worldwide 1. A major problem in the management and treatment of AD is recurrent skin infections with Staphylococcus aureus 2 , resulting in repeated flares, sustained disease activity and frequent antibiotic treatment. This increased susceptibility to skin infections has been attributed to decreased levels of antimicrobial peptides (AMPs) 3. AMPs act as direct antimicrobial effector molecules, creating an important first line of defense in the skin, and possess broad antimicrobial activity 4. Furthermore, AMPs are essential immune mediators, linking the adaptive and innate immune response, regulating cytokine response, attracting immune cells as well as interacting with the skin microbiome 5-7. Multifaceted functions of AMPs are described, promoting immunity as well as participating in the pathogenesis of certain inflammatory diseases 8,9 , making them interesting targets for therapeutic development and treatment of inflammatory diseases. Until now most studies on AMPs in AD skin have identified AMPs in full thickness skin biopsies 3,10-13 and only few studies using skin washing fluid, and tape stripping technique have been presented 14-16. The aim of the present study was to determine the concentration of different AMPs in lesional and non-lesional AD skin, and in healthy control skin, using tape stripping technique and commercially available ELISA kits, with focus on stratum corneum, where the antimicrobial function is anticipated to be of greatest importance. Results Clinical characteristics. SCORAD for AD patients ranged from 7.7-61.5, with a median of 33.8 (25-75 th percentile = 18.28-44.18) (Table 1). TEWL (baseline) was significantly higher in AD non-lesional skin (median TEWL = 9.2, 25-75 th percentile = 6.95-12.6) compared to healthy control skin (median TEWL = 5.9, 25-75 th percentile = 5.2-6.85) p = 0.04. TEWL after tape stripping was measured, and resulted in a median increase in TEWL of 60.95 g/cm2/h (25-75 th percentile = 47.08-76.83). All participants showed a noticeably increase in
and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according ... more and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according to standardized recommendations for epidemiological typing of B. pertussis. There were 81 different PFGE profiles, five of which (BpSR3, BpSR5, BpSR10, BpSR11, and BpSR12) were observed in 61% of the 396 isolates and shown to be predominant in almost all countries. The major profile, BpSR11, showed a decreasing trend from 25% to 30% in 1998 to 2005 to 13% in 2007 to 2009, and there were increases in BpSR3 and BpSR10 from 0% and 8% to 21% and 22%, respectively. One difference between these profiles is that BpSR11 contains isolates harboring the fim3-2 allele and BpSR3 and BpSR10 contain isolates harboring the fim3-1 allele. The total proportion of the five predominant profiles increased from 44% in 1998 to 2001 to 63% in 2004 to 2005 to 70% in 2007 to 2009. In conclusion, common PFGE profiles were identified in B. pertussis populations circulating in European countries with different vaccination programs and different vaccine coverages. These prevalent isolates contain the novel pertussis toxin promoter ptxP3 allele. However, there is evidence for diversifying selection between ptxP3 strains characterized by distinct PFGE profiles. This work shows that, even within a relatively short time span of 10 years, successful isolates which spread through Europe and cause large shifts in B. pertussis populations may emerge.
Since 2012, have we in Denmark observed an increase of invasive pneumococcal infections (IPD) due... more Since 2012, have we in Denmark observed an increase of invasive pneumococcal infections (IPD) due to Streptococcus pneumoniae serotype 24F. We here present epidemiological data on 24F IPD cases, and characterization of 48 24F clinical isolates based on clonal relationship, antimicrobial resistance (AMR) determinants and virulence factors. IPD surveillance data from (1999-2016) were used to calculate the incidence and age-distribution of serotype 24F IPD and the effect of pneumococcal conjugated vaccines (PCV). Characterization of forty-eight 24F isolates (14.7% of all 24F isolates from the period) was based on whole-genome sequencing analysis (WGS). The IPD cases of serotype 24F showed a significant increase (p < 0.05) for all age groups after the PCV-13 introduction in 2010. The majority of tested 24F isolates consisted of two MLST types, i.e. the ST72 and the ST162. Serotype 24F IPD increased in Denmark after the PCV-13 introduction in parallel with an increase of the ST162 clone. The genotypic penicillin binding protein (PBP) profile agreed with the phenotypical penicillin susceptibility. The virulence genes lytA, ply, piaA, piaB, piaC, rspB and the cpsA/wzg were detected in all 24F isolates, while the pspA and zmpC genes were absent. Streptococcus pneumoniae is a ubiquitous bacterium present in the commensal bacterial community in the human nasopharynx. It is responsible for non-invasive infections as well as invasive pneumococcal disease (IPD) with high morbidity and mortality especially among young children and the elderly 1. The introduction of the pneumococcal conjugated vaccine (PCV) provided an effective protection against IPD in children. The first PCV on the global market was Prevenar 7 (PCV-7) (Pfizer Vaccines) in 2000 including seven different serotypes (4, 6B, 9V, 14, 18C, 19F and 23F), followed by the 10-valent pneumococcal-conjugate vaccine (PCV-10) (Synflorix, GlaxoSmithKline Biologicals) in 2009 including the serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F, and by the Prevenar 13 vaccine (PCV-13) (Pfizer Vaccines) in 2010 including the serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F and 23F 1. Besides the conjugate vaccines, a pneumococcal polysaccharide vaccine (PPV-23) (Pneumovax ® , Merck) based on purified capsular polysaccharides from 23 different serotypes, was introduced in 1996. The PPV-23 vaccine is recommended for patients older than 2 years of age and of high risk for IPD and for the 65+ years age group 2,3. With the introduction of PCV, a significant reduction of IPD cases caused by the included PCV serotypes was seen, but at the same time serotype replacement was observed, with the appearance of new pneumococcal serotypes not included in the vaccines 1. One of the non-PCV serotypes that has emerged in recent years is serotype 24F 4,5. The non-vaccine serotype 24F is responsible for many penicillin non-susceptible related IPD cases 6. Serotype 24F is also linked to erythromycin-clindamycin and tetracycline resistance and is one of the main serotypes that was recovered from young children with IPD between 2011 and 2012 in France 7. After the introduction of PCV13 in 2010 in France, serotype 24F, including other non-vaccine serotypes (10A, 12F and 15A), were responsible for approximately 39% of pneumococcal meningitis (PM) cases in children below 5 years of age from 2012 to 2014 8. During the last five years, a small increase of IPD cases with serotype 24F has been observed in Denmark 1. Because the serotype 24F is an emerging non-pneumococcal vaccine serotype, which to our knowledge is not a part of any pneumococcal vaccine or as part of planned future pneumococcal vaccine. Is it therefore essential Department of Bacteria, Parasites and fungi, Statens Serum institut, copenhagen, Denmark. correspondence and requests for materials should be addressed to H.-C.S.
Background Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we e... more Background Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we examined EM patients in Norwegian general practice to find the proportion exposed to tick-transmitted microorganisms other than Borrelia, and the impact of co-infection on the clinical manifestations and disease duration. Methods Skin biopsies from 139/188 EM patients were analyzed using PCR for Neoehrlichia mikurensis, Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Follow-up sera from 135/188 patients were analyzed for spotted fever group (SFG) Rickettsia, A. phagocytophilum and Babesia microti antibodies, and tested with PCR if positive. Day 0 sera from patients with fever (8/188) or EM duration of ≥ 21 days (69/188) were analyzed, using PCR, for A. phagocytophilum, Rickettsia spp., Babesia spp. and N. mikurensis. Day 14 sera were tested for TBEV IgG. Results We detected no microorganisms in the skin biopsies nor in the sera of patients with fever or prolonged EM duration. ...
Staphylococcus aureus is recognized as an important pathogen causing a wide spectrum of diseases.... more Staphylococcus aureus is recognized as an important pathogen causing a wide spectrum of diseases. Here we examined the antimicrobial effects of the lectin isolated from leaves of Schinus terebinthifolia Raddi (SteLL) against S. aureus using in vitro assays and an infection model based on Galleria mellonella larvae. The actions of SteLL on mice macrophages and S. aureus-infected macrophages were also evaluated. SteLL at 16 µg/mL (8 × MIC) increased cell mass and DNA content of S. aureus in relation to untreated bacteria, suggesting that SteLL impairs cell division. Unlike ciprofloxacin, SteLL did not induce the expression of recA, crucial for DNA repair through SOS response. The antimicrobial action of SteLL was partially inhibited by 50 mM N-acetylglucosamine. SteLL reduced staphyloxathin production and increased ciprofloxacin activity towards S. aureus. This lectin also improved the survival of G. mellonella larvae infected with S. aureus. Furthermore, SteLL induced the release of ...
Klebsiella pneumoniae is a common cause of sepsis and is particularly associated with healthcare-... more Klebsiella pneumoniae is a common cause of sepsis and is particularly associated with healthcare-associated infections. New strategies are needed to prevent or treat infections due to the emergence of multi-drug resistant K. pneumoniae. The goal of this study was to determine the diversity and distribution of O (lipopolysaccharide) and K (capsular polysaccharide) antigens on a large (>500) global collection of K. pneumoniae strains isolated from blood to inform vaccine development efforts. A total of 645
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