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"Huebner, Johannes"
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Advances and Prospects in Vaccine Development against Enterococci
by
Kalfopoulou, Ermioni
,
Huebner, Johannes
in
Bacterial vaccines
,
Development and progression
,
Enterococcal infections
2020
Enterococci are the second most common Gram-positive pathogen responsible for nosocomial infections. Due to the limited number of new antibiotics that reach the medical practice and the resistance of enterococci to the current antibiotic options, passive and active immunotherapies have emerged as a potential prevention and/or treatment strategy against this opportunistic pathogen. In this review, we explore the pathogenicity of these bacteria and their interaction with the host immune response. We provide an overview of the capsular polysaccharides and surface-associated proteins that have been described as potential antigens in anti-enterococcal vaccine formulations. In addition, we describe the current status in vaccine development against enterococci and address the importance and the current advances toward the development of well-defined vaccines with broad coverage against enterococci.
Journal Article
Identification of cross-reactive vaccine antigen candidates in Gram-positive ESKAPE pathogens through subtractive proteome analysis using opsonic sera
2025
The Gram-positive pathogens of the ESKAPE group, Enterococcus faecium, and Staphylococcus aureus , are well-known to pose a serious risk to human health because of their high virulence and numerous drug resistances. To narrow down the list of previously identified promising protein vaccine candidates, a combination of several antigen discovery approaches was performed, in particular a “false positive analysis” of peptides generated by trypsin shaving with a subtractive proteome analysis. The final list of nine potential antigens included AdcA au , a protein performing the same function as AdcA fm , an already discovered antigen in enterococci. Bioinformatic analyses revealed that AdcA au and AdcA fm share a sequence identity of 41.2% and that the conserved regions present a high antigenicity. AdcA au was selected for further investigation and the results reported in this manuscript demonstrate the opsonic properties of AdcA au -specific antibodies against the Staphylococcus aureus strain MW2, as well as their cross-binding and cross-opsonic activity against several S. aureus, E. faecium , and E. faecalis strains. The experimental design revealed several promising vaccine candidates, including the newly identified S. aureus antigen, AdcA au . The study shows its potential as a vaccine candidate to prevent infections by dangerous Gram-positive ESKAPE pathogens.
Journal Article
Accumulation of Pharmaceuticals, Enterococcus, and Resistance Genes in Soils Irrigated with Wastewater for Zero to 100 Years in Central Mexico
by
Broszat, Melanie
,
Willaschek, Elisha
,
Siemens, Jan
in
Accumulation
,
Agricultural Irrigation
,
Agriculture
2012
Irrigation with wastewater releases pharmaceuticals, pathogenic bacteria, and resistance genes, but little is known about the accumulation of these contaminants in the environment when wastewater is applied for decades. We sampled a chronosequence of soils that were variously irrigated with wastewater from zero up to 100 years in the Mezquital Valley, Mexico, and investigated the accumulation of ciprofloxacin, enrofloxacin, sulfamethoxazole, trimethoprim, clarithromycin, carbamazepine, bezafibrate, naproxen, diclofenac, as well as the occurrence of Enterococcus spp., and sul and qnr resistance genes. Total concentrations of ciprofloxacin, sulfamethoxazole, and carbamazepine increased with irrigation duration reaching 95% of their upper limit of 1.4 µg/kg (ciprofloxacin), 4.3 µg/kg (sulfamethoxazole), and 5.4 µg/kg (carbamazepine) in soils irrigated for 19-28 years. Accumulation was soil-type-specific, with largest accumulation rates in Leptosols and no time-trend in Vertisols. Acidic pharmaceuticals (diclofenac, naproxen, bezafibrate) were not retained and thus did not accumulate in soils. We did not detect qnrA genes, but qnrS and qnrB genes were found in two of the irrigated soils. Relative concentrations of sul1 genes in irrigated soils were two orders of magnitude larger (3.15 × 10(-3) ± 0.22 × 10(-3) copies/16S rDNA) than in non-irrigated soils (4.35 × 10(-5)± 1.00 × 10(-5) copies/16S rDNA), while those of sul2 exceeded the ones in non-irrigated soils still by a factor of 22 (6.61 × 10(-4) ± 0.59 × 10(-4) versus 2.99 × 10(-5) ± 0.26 × 10(-5) copies/16S rDNA). Absolute numbers of sul genes continued to increase with prolonging irrigation together with Enterococcus spp. 23S rDNA and total 16S rDNA contents. Increasing total concentrations of antibiotics in soil are not accompanied by increasing relative abundances of resistance genes. Nevertheless, wastewater irrigation enlarges the absolute concentration of resistance genes in soils due to a long-term increase in total microbial biomass.
Journal Article
Investigation of cross-opsonic effect leads to the discovery of PPIase-domain containing protein vaccine candidate to prevent infections by Gram-positive ESKAPE pathogens
by
Romero-Saavedra, Felipe
,
Laverde, Diana
,
Kramarska, Eliza
in
Animals
,
Antibiotics
,
Antibodies
2024
Background
Enterococcus faecium
and
Staphylococcus aureus
are the Gram-positive pathogens of the ESKAPE group, known to represent a great threat to human health due to their high virulence and multiple resistances to antibiotics. Combined, enterococci and
S. aureus
account for 26% of healthcare-associated infections and are the most common organisms responsible for blood stream infections. We previously showed that the peptidyl-prolyl cis/trans isomerase (PPIase) PpiC of
E. faecium
elicits the production of specific, opsonic, and protective antibodies that are effective against several strains of
E. faecium
and
E. faecalis
. Due to the ubiquitous characteristics of PPIases and their essential function within Gram-positive cells, we hypothesized a potential cross-reactive effect of anti-PpiC antibodies.
Results
Opsonophagocytic assays combined with bioinformatics led to the identification of the foldase protein PrsA as a new potential vaccine antigen in
S. aureus
. We show that PrsA is a stable dimeric protein able to elicit opsonic antibodies against the
S. aureus
strain MW2, as well as cross-binding and cross-opsonic in several
S. aureus
,
E. faecium
and
E. faecalis
strains.
Conclusions
Given the multiple antibiotic resistances
S. aureus
and enterococci present, finding preventive strategies is essential to fight those two nosocomial pathogens. The study shows the potential of PrsA as an antigen to use in vaccine formulation against the two dangerous Gram-positive ESKAPE bacteria. Our findings support the idea that PPIases should be further investigated as vaccine targets in the frame of pan-vaccinomics strategy.
Journal Article
Clinical benefits of introducing real-time multiplex PCR for cerebrospinal fluid as routine diagnostic at a tertiary care pediatric center
by
Hagen, Alexandra
,
Eichinger, Anna
,
Meyer-Bühn, Melanie
in
Antiinfectives and antibacterials
,
Antimicrobial agents
,
Aseptic meningitis
2019
BackgroundSepsis-like illness with suspected meningitis or encephalitis is a common reason for using empiric antimicrobial therapy in infants and children. However, in cases of viral meningitis not covered by these antimicrobials, this management is ineffective and due to side effects potentially harmful.MethodsA retrospective analysis of cerebrospinal fluid (CSF) multiplex PCRs (Biofire FilmArray®) in children with clinical suspicion of meningitis, encephalitis or sepsis-like illness was performed over the period of 1 year. Subsequently, a subgroup of children (age of 8–84 days of life) diagnosed with viral meningitis (enterovirus, HHV-6, human parechovirus) was compared to an age-matched control group.ResultsDuring the study period, the multiplex PCR panel was performed on 187 individual CSF samples that met the inclusion criteria. About half of the patients (92/187) were less than 1 year of age. In 27 cases (14.4%), the PCR yielded a positive result with the majority (12/27) being indicative of an enteroviral infection. In the age group of 8–84 days of life, 36.4% of the patients had a positive result. When the patients with a PCR positive for a viral agent were compared to an age-matched group of patients, no differences were observed regarding symptoms and laboratory parameters. However, the duration of antimicrobial therapy could be significantly reduced through the use of multiplex PCR.ConclusionThe use of on-site diagnostic multiplex PCR was able to reduce the use of antimicrobials in selected cases. This test can guide clinical decisions earlier during the course of medical care compared to standard diagnostics.
Journal Article
Pediatric antibiotic stewardship: successful interventions to reduce broad-spectrum antibiotic use on general pediatric wards
by
Alenka Pecar
,
Rafael T. Mikolajczyk
,
Johannes P. Borde
in
Anti-Bacterial Agents
,
Anti-Bacterial Agents - therapeutic use
,
Antibiotic resistance
2017
Purpose
Antibiotic stewardship programs (ASP) optimize antibiotic usage and combat antibiotic resistance of bacteria. The objective of this study was to assess the impact of specific ASP interventions on antibiotic consumption in general pediatric wards.
Methods
We conducted a prospective study to compare a pre-intervention (Sept.–Dec. 2014) and post-intervention (Sept.–Dec. 2015) period. An ASP bundle was established including (1) infectious diseases (ID) ward rounds (prospective-audit-with-feedback), (2) ID consultation service, (3) internal guidelines on empiric antibiotic therapy. Medical records on four general pediatric wards were reviewed daily to analyze: (1) antibiotic consumption, (2) antibiotic dosage ranges according to local guidelines, and (3) guideline adherence for community-acquired pneumonia (CAP).
Results
Antibiotic prescribing for 273 patients (pre-intervention) was compared to 263 patients (post-intervention). Antibiotic prescription rate did not change (30.6 vs. 30.5%). However, overall days-of-therapy and length-of-therapy decreased by 10.5 and 7.7%, respectively. Use of cephalosporins and fluoroquinolones decreased by 35.5 and 59.9%, whereas the use of penicillins increased by 15.0%. An increase in dosage accuracy was noted (78.8 vs. 97.6%) and guideline adherence for CAP improved from 39.5 to 93.5%. Between the two study periods, no adverse effects regarding length of hospital stay and in-hospital mortality were observed.
Conclusions
Our data demonstrate that implementation of an ASP was associated with a profound improvement of rational antibiotic use and, therefore, patient safety. Considering the relatively short observation period, the long-term effects of our ASP bundle need to be further investigated.
Journal Article
Cross-sectional seroprevalence surveys of SARS-CoV-2 antibodies in children in Germany, June 2020 to May 2021
2022
The rate of SARS-CoV-2 infections in children remains unclear due to many asymptomatic cases. We present a study of cross-sectional seroprevalence surveys of anti-SARS-CoV-2 IgG in 10,358 children recruited in paediatric hospitals across Germany from June 2020 to May 2021. Seropositivity increased from 2.0% (95% CI 1.6, 2.5) to 10.8% (95% CI 8.7, 12.9) in March 2021 with little change up to May 2021. Rates increased by migrant background (2.8%, 4.4% and 7.8% for no, one and two parents born outside Germany). Children under three were initially 3.6 (95% CI 2.3, 5.7) times more likely to be seropositive with levels equalising later. The ratio of seropositive cases per recalled infection decreased from 8.6 to 2.8. Since seropositivity exceeds the rate of recalled infections considerably, serologic testing may provide a more valid estimate of infections, which is required to assess both the spread and the risk for severe outcomes of SARS-CoV-2 infections.
Children are less likely to be infected with SARS-CoV-2 and develop less severe disease than adults, which makes estimation of infection rates challenging. Here, the authors conduct seroprevalence surveys of children in Germany, describe changes in prevalence over time, and identify risk factors for infection.
Journal Article
Comparison of antibiotic and acyclovir usage before and after the implementation of an on-site FilmArray meningitis/encephalitis panel in an academic tertiary pediatric hospital: a retrospective observational study
by
Hagen, Alexandra
,
Eichinger, Anna
,
Schober, Tilmann
in
Acyclovir
,
Acyclovir - therapeutic use
,
Adolescent
2020
Background
Prompt initiation of empiric therapy is common practice in case of suspected meningitis or encephalitis. However, in children the most common pathogens are viruses that usually do not require and are not covered by the applied anti-infective treatment. Novel multiplex PCR (mPCR) panels provide rapid on-site diagnostic testing for a variety of pathogens. This study compared empiric antibiotic and acyclovir usage before and after the introduction of an on-site FilmArray Meningitis/Encephalitis Panel (FA ME Panel).
Methods
We retrospectively compared data for empiric antibiotic and acyclovir usage between pediatric patients with suspected central nervous system (CNS) infection receiving mPCR testing and a matched historical control group. Patients were matched by age and suspected CNS infection. We included all patients for whom empiric antibiotics and/or acyclovir were prescribed.
Results
Each study group consisted of 46 patients with 29 (63.0%) infants and 17 (37.0%) older children. A viral pathogen was diagnosed in 5/46 (10.9%) patients in the control group (all enteroviruses) and in 14/46 (30.4%) patients in the mPCR group (enterovirus
n
= 9; human herpesvirus 6 (HHV-6)
n
= 5), (
p
= 0.038)). Length of Therapy (LoT) and Days of Therapy (DoT) for antibiotics were significantly lower for infants (4.0 vs. 3.0, p = 0.038 and 8.0 vs. 6.0,
p
= 0.015, respectively). Acyclovir therapy was significantly shorter for both, infants and older children (3.0 vs. 1.0 day,
p
< 0.001 for both age groups).
Conclusion
The findings of our study suggest that the introduction of a FA ME Panel into clinical routine procedures is associated with a significantly reduced LoT and DoT of empiric anti-infective treatment in children with suspected meningoencephalitis. The largest effect was observed in infants.
Journal Article
Weekly SARS-CoV-2 Sentinel Surveillance in Primary Schools, Kindergartens, and Nurseries, Germany, June‒November 2020
2021
We investigated severe acute respiratory syndrome coronavirus 2 infections in primary schools, kindergartens, and nurseries in Germany. Of 3,169 oropharyngeal swab specimens, only 2 were positive by real-time reverse transcription PCR. Asymptomatic children attending these institutions do not appear to be driving the pandemic when appropriate infection control measures are used.
Journal Article
Phage-mediated Dispersal of Biofilm and Distribution of Bacterial Virulence Genes Is Induced by Quorum Sensing
2015
The microbiome and the phage meta-genome within the human gut are influenced by antibiotic treatments. Identifying a novel mechanism, here we demonstrate that bacteria use the universal communication molecule AI-2 to induce virulence genes and transfer them via phage release. High concentrations (i.e. 100 μM) of AI-2 promote dispersal of bacteria from already established biofilms, and is associated with release of phages capable of infecting other bacteria. Enterococcus faecalis V583ΔABC harbours 7 prophages in its genome, and a mutant deficient in one of these prophages (i.e. prophage 5) showed a greatly reduced dispersal of biofilm. Infection of a probiotic E. faecalis strain without lytic prophages with prophage 5 resulted in increased biofilm formation and also in biofilm dispersal upon induction with AI-2. Infection of the probiotic E. faecalis strain with phage-containing supernatants released through AI-2 from E. faecalis V583ΔABC resulted in a strong increase in pathogenicity of this strain. The polylysogenic probiotic strain was also more virulent in a mouse sepsis model and a rat endocarditis model. Both AI-2 and ciprofloxacin lead to phage release, indicating that conditions in the gastrointestinal tract of hospitalized patients treated with antibiotics might lead to distribution of virulence genes to apathogenic enterococci and possibly also to other commensals or even to beneficial probiotic strains.
Journal Article