Barium sulphate microparticles are taken up by three different cell types: HeLa, THP-1, and hMSC.

Cytotoxicity and cellular uptake of spherical barium sulphate microparticles (diameter 1 µm) were studied with three different cell lines, i.e. THP-1 cells (monocytes; model for a phagocytosing cell line), HeLa cells (epithelial cells; model for a non-phagocytosing cell line), and human mesenchymal stem cells (hMSCs; model for non-phagocytosing primary cells). Barium sulphate is a chemically and biologically inert solid which allows to distinguish two different processes, e.g. the particle uptake and potential adverse biological reactions. Barium sulphate microparticles were surface-coated by carboxymethylcellulose (CMC) which gave the particles a negative charge. Fluorescence was added by conjugating 6-aminofluorescein to CMC. The cytotoxicity of these microparticles was studied by the MTT test and a live/dead assay. The uptake was visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The particle uptake mechanism was quantified by flow cytometry with different endocytosis inhibitors in THP-1 and HeLa cells. The microparticles were easily taken up by all cell types, mostly by phagocytosis and micropinocytosis, within a few hours. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is of primary importance in nanomedicine, drug delivery, and nanotoxicology. It is commonly assumed that cells take up only nanoparticles unless they are able to phagocytosis. Here, we demonstrate with chemically and biologically inert microparticles of barium sulphate that even non-phagocytosing cells like HeLa and hMSCs take up microparticles to a considerable degree. This has considerable implication in biomaterials science, e.g. in case of abrasive debris and particulate degradation products from implants like endoprostheses.

Infection prevention and control between legal requirements and German Society for Hygiene and Microbiology expert assessments: a cross-sectional study in September-November 2022.

BACKGROUND: In contrast to the beginning of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), pandemic, more and more hospital issues are now regulated by policy. AIM: To identify differences between expert recommendations and legal requirements regarding infection prevention and control (IPC) strategies. METHODS: A cross-sectional study was conducted between 29th September 2022 and 3rd November 2022 addressing 1319 members of the German Society for Hygiene and Microbiology. The response rate was 12%. This paper reports the expert recommendations on different IPC strategies. FINDINGS: The majority (66%) of experts recommended universal mask usage, with 34% recommending it seasonally, even after the SARS-CoV-2 pandemic. Medical microbiology (MM) experts were more likely to recommend continuing to wear the masks indefinitely compared with IPC experts. Concerning the mask type, medical masks were recommended more frequently by IPC experts (47.3%), while FFP2 masks were preferred by MM experts (31.8%). The majority (54.7%) of experts recommended universal screening of employees, mainly in settings with extremely vulnerable patients and if regional incidence rates were high, at a frequency of twice per week. The dominant advice (recommended by at least 50% of experts) for employees exposed to SARS-CoV-2 was daily testing and wearing a mask, regardless of the length of exposure. CONCLUSIONS: Expert recommendations deviate from the legal requirements and appear to be more differentiated and proportional. The influence of specific experience and expertise on mask recommendations should be investigated in more detail. For relevant policy decisions, a quick, focused and broad-based consultation of expertise could be of added value.

Evaluation of the Accelerate Pheno System for Rapid Identification and Antimicrobial Susceptibility Testing of Positive Blood Culture Bottles Inoculated with Primary Sterile Specimens from Patients with Suspected Severe Infections.

The Accelerate Pheno system is approved for rapid identification and phenotypic antimicrobial susceptibility testing (AST) of microorganisms grown from positive blood cultures inoculated with blood from septic patients. We evaluated the performance of the system for identification and AST from positive blood culture bottles inoculated with primary sterile nonblood specimens from patients with suspected severe infections. One hundred positive blood culture bottles with primary sterile specimens (63 cerebrospinal fluids, 16 ascites, 7 pleural fluids, 4 vitreous fluids, 5 joint aspirates, and 5 other aspirates) from 100 patients were included. Pathogen identification was in agreement with conventional methods for 72 of 100 cultures (72%) and for 81 of 112 (72%) pathogens when considering all pathogens and for 72 of 92 (78%) cultures and 81 of 104 (78%) pathogens when considering on-panel pathogens only. Eight of 31 isolates (26%) not identified by APS were pathogens not included in the APS panel. APS and conventional methods accordingly identified all pathogens from two of nine polymicrobial cultures (22%). APS generated antimicrobial resistance results for 57 pathogens of 57 cultures. The overall category agreement between APS and culture-based AST was 91.2%; and the rate for minor errors was 6.9%, for major was 1.7%, and for very major errors was 0.2%. APS may accelerate pathogen identification and phenotypic AST from positive blood culture bottles inoculated with primary sterile specimens from patients with serious infections, especially for hospitals without an on-site microbiology laboratory. However, the inclusion of nonblood specimens with a high likelihood of polymicrobial infections may result in an inferior performance.

[The microbiome in head and neck tumors-initial findings and outlook]. / Das Mikrobiom bei Kopf-Hals-Tumoren ­ erste Erkenntnisse und Ausblick.

Technical progress in molecular biology has allowed for a more detailed analysis of the composition of the human microbiome in recent years. Inter- and intraindividual differences in microbiome composition have been demonstrated, which in part correlate with the occurrence of certain diseases. For some of the so-called oncomicrobes, a direct relationship between their effect on the host organism and carcinogenesis has been demonstrated, predominantly for gastrointestinal cancers. Initial results for head and neck cancer show inter- and intraindividual differences in the local microbiota of the tumor environment, with certain bacterial strains over- or underrepresented. Our results confirm these findings, e.g., by showing a relative abundance of fusobacteria in tumor tissue while streptococci were relatively reduced. Currently available results show a high degree of inter- and intraindividual variation, thus requiring larger patient cohorts for functional analyses.

Performance of the AsperGenius® PCR assay for detecting azole resistant Aspergillus fumigatus in BAL fluids from allogeneic HSCT recipients: A prospective cohort study from Essen, West Germany.

In this study a commercially available multiplex real-time PCR (AsperGenius®) was evaluated for its efficacy in detecting Aspergillus fumigatus and azole resistance markers in comparison with conventional culture methods and galactomannan (GM) testing from BAL fluids in allogeneic HSCT recipients. Between January 2015 and May 2017 100 allogeneic HSCT recipients with pulmonary infiltrates and suspicion of invasive fungal infection were recruited to the study from a tertiary care center in Germany. BAL fluid was routinely assessed using the following diagnostic tests: AsperGenius® PCR assay, GM testing (cut-off: 1.0) and conventional culture. Susceptibility testing of azoles was performed by using Etest and, in case presenting elevated MICs, PCR for mutations in the cyp51A gene was carried out. Criteria of EORTC/MSG were used to classify the patients for invasive fungal disease. According to the EORTC/MSG criteria 23 patients presented with probable invasive aspergillosis (IA). Aspergillus PCR showed a sensitivity of 65% for probable IA cases. A combination of PCR and GM results in BAL displayed a sensitivity of 96% (22/23) and 100% specificity. Mutations in the cyp51A gene were detected by PCR in three cases (3/23; 13%) which were also found resistant with the culture method. In one case a Y121F/T289A mutation and in two cases a L98H were found. The combination of a commercial Aspergillus PCR assay and GM testing from BAL demonstrated a high sensitivity and specificity for diagnosing IA in allogeneic HSCT recipients. The Aspergillus PCR assay was not superior in detecting azole resistant A. fumigatus compared to culture.

A systematic electron microscopic study on the uptake of barium sulphate nano-, submicro-, microparticles by bone marrow-derived phagocytosing cells.

Nanoparticles can act as transporters for synthetic molecules and biomolecules into cells, also in immunology. Antigen-presenting cells like dendritic cells are important targets for immunotherapy in nanomedicine. Therefore, we have used primary murine bone marrow-derived phagocytosing cells (bmPCs), i.e. dendritic cells and macrophages, to study their interaction with spherical barium sulphate particles of different size (40 nm, 420 nm, and 1 µm) and to follow their uptake pathway. Barium sulphate is chemically and biologically inert (no dissolution, no catalytic effects), i.e. we can separate the particle uptake effect from potential biological reactions. The colloidal stabilization of the nanoparticles was achieved by a layer of carboxymethylcellulose (CMC) which is biologically inert and gives the particles a negative zeta potential (i.e. charge). The particles were made fluorescent by conjugating 6-aminofluoresceine to CMC. Their uptake was visualized by flow cytometry, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and correlative light and electron microscopy (CLEM). Barium sulphate particles of all sizes were readily taken up by dendritic cells and even more by macrophages, with the uptake increasing with time and particle concentration. They were mainly localized inside phagosomes, heterophagosomes, and in the case of nanoparticles also in the nearby cytosol. No particles were found in the nucleus. In nanomedicine, inorganic nanoparticles from the nanometer to the micrometer size are therefore well suited as transporters of biomolecules, including antigens, into dendritic cells and macrophages. The presented model system may also serve to describe the aseptic loosening of endoprostheses caused by abrasive wear of inert particles and the subsequent cell reaction, a question which relates to the field of nanotoxicology. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is at the heart of nanomedicine and nanotoxicology, including abrasive wear from endoprostheses. It also comprises the immunological reaction to different kinds of nanomaterials, triggered by an immune response, e.g. by antigen-presenting cells. However, it is often difficult to separate the particle effect from a chemical or biochemical reaction to particles or their cargo. We show how chemically inert barium sulphate particles with three different sizes (nano, sub-micro, and micro) interact with relevant immune cells (primary dendritic cells and macrophages). Particles of all three sizes are readily taken up into both cell types by phagocytosis, but the uptake by macrophages is significantly more prominent than that by dendritic cells. The cells take up particles until they are virtually stuffed, but without direct adverse effect. The uptake increases with time and particle concentration. Thus, we have an ideal model system to follow particles into and inside cells without the side effect of a chemical particle effect, e.g. by degradation or ion release.

Prevalence and characterization of azole-resistant Aspergillus fumigatus in patients with cystic fibrosis: a prospective multicentre study in Germany.

Objectives: Aspergillus fumigatus is the most prevalent filamentous fungus in the respiratory tract of patients with cystic fibrosis (CF). The aim of this prospective multicentre study was to investigate the prevalence of azole-resistant A. fumigatus (ARAF) in respiratory secretions from CF patients across Germany and to characterize ARAF isolates by phenotypic and molecular methods. Methods: Twelve tertiary care centres from Germany participated in the study. In total, 2888 A. fumigatus isolates from 961 CF patients were screened for ARAF by using azole-containing agar plates. Antifungal susceptibility testing of isolates was performed by broth microdilution according to EUCAST guidelines. Analysis of mutations mediating resistance was performed using PCR and sequencing of the cyp51A gene. Furthermore, genotyping by microsatellite PCR was performed. Results: Of a total of 2888 A. fumigatus isolates, 101 isolates from 51 CF patients were found to be azole resistant (prevalence per patient 5.3%). The Essen centre had the highest prevalence (9.1%) followed by Munich (7.8%), Münster (6.0%) and Hannover (5.2%). Most ARAF isolates (n = 89) carried the TR34/L98H mutation followed by eight G54E/R, one TR46/Y121F/T289A and one F219S mutation. In two isolates no mutation was found. Genotyping results showed no major clustering. Forty-five percent of CF patients with ARAF had previously received azole therapy. Conclusions: This is the first multicentre study analysing the prevalence of ARAF isolates in German CF patients. Because of a resistance rate of up to 9%, susceptibility testing of A. fumigatus isolates from CF patients receiving antifungal treatment should be part of standard diagnostic work-up.

The lung microbiome in patients with pneumocystosis.

BACKROUND: Pneumocystis jirovecii pneumonia (PCP) is an opportunistic fungal infection that is associated with a high morbidity and mortality in immunocompromised individuals. In this study, we analysed the microbiome of the lower respiratory tract from critically ill intensive care unit patients with and without pneumocystosis. METHODS: Broncho-alveolar fluids from 65 intubated and mechanically ventilated intensive care unit patients (34 PCP+ and 31 PCP- patients) were collected. Sequence analysis of bacterial 16S rRNA gene V3/V4 regions was performed to study the composition of the respiratory microbiome using the Illumina MiSeq platform. RESULTS: Differences in the microbial composition detected between PCP+ and PCP- patients were not statistically significant on class, order, family and genus level. In addition, alpha and beta diversity metrics did not reveal significant differences between PCP+ and PCP- patients. The composition of the lung microbiota was highly variable between PCP+ patients and comparable in its variety with the microbiota composition of the heterogeneous collective of PCP- patients. CONCLUSIONS: The lower respiratory tract microbiome in patients with pneumocystosis does not appear to be determined by a specific microbial composition or to be dominated by a single bacterial species.

Emergence of linezolid- and vancomycin-resistant Enterococcus faecium in a department for hematologic stem cell transplantation.

BACKGROUND: Prevalence of vancomycin-resistant enterococci has increased in Germany. Here, we report the cluster of linezolid- and vancomycin-resistant Enterococcus faecium (LVRE) in a German department for hematologic stem cell transplantation (HSCT). METHODS: In this retrospective analysis we included all patients with LVRE in a university-based department for HSCT in 2014 and 2015. Patients chart reviews were used to investigate the epidemiology and clinical outcome. Available LVRE isolates underwent detailed microbiological characterization and genotyping by pulsed-field gel electrophoresis (PFGE). RESULTS: In total, 20 patients with LVRE were identified within the observed time period. All except two patients underwent allogeneic HSCT. Surveillance culture results from incoming patients and chart review revealed that 10 of 20 patients were colonized at hospital admission. Eight of 10 patients with in-hospital acquired LVRE had previous linezolid treatment. Analysis of spatio-temporal patterns showed no evidence for LVRE patient-to-patient or environment-to-patient transmission within the HSCT department. In five cases (25 %) LVRE bloodstream infection occurred. Nine LVRE isolates could be saved for characterization. Eight isolates carried vanA, one isolate vanB. PFGE analysis showed that four different LVRE clones were responsible for the cluster. One single genotype was present in six LVRE isolates whereupon the corresponding patients were all referred from the same hospital to the HSCT department. CONCLUSIONS: This is the first report demonstrating the emergence of LVRE in a German HSCT department. (L)VRE screening at patients' admission and appropriate infection control strategies were sufficient to prevent any transmission. Further studies in this predisposed patient collective are warranted.

In Vitro Activity of Isavuconazole against Rasamsonia Species.

The in vitro susceptibilities to the novel triazole isavuconazole and six other antifungal agents of a large collection of Rasamsonia isolates (n = 47) belonging to seven species were determined. Isavuconazole and voriconazole had no in vitro activity (MIC, >32 mg/liter) against isolates of the Rasamsonia argillacea species complex. The echinocandins were the most potent antifungal drugs against all of the isolates tested (minimum effective concentration, ≤0.19 mg/liter).

IL-10 downregulates CXCR3 expression on Th1 cells and interferes with their migration to intestinal inflammatory sites.

Inflammatory bowel disease (IBD) is characterized by chronic, uncontrolled inflammation in the intestinal mucosa. Although the etiology is poorly understood, it is widely accepted that loss of tolerance is involved in the development of IBD. Therefore, re-establishing tolerance or gut homeostasis is one of the key features in the development of new therapeutic strategies. Here we show that antigen targeting to DEC-205 on dendritic cells leads to an interleukin (IL)-10-dependent downregulation of C-X-C chemokine receptor 3 (CXCR3) expression on differentiated antigen-specific T helper type 1 (Th1) cells in vivo. This downregulation interferes with the migration of Th1 cells into the gut and protects mice against severe acute and relapsing intestinal inflammation. Moreover, CD4(+)CXCR3(+) T cells are highly enriched in the inflamed mucosa of IBD patients. Interference with this pathway may therefore be a promising approach for the treatment of IBD. In conclusion, we propose a hitherto undescribed mechanism by which IL-10 can act on effector T cells and orchestrate intestinal immune responses.

Emergence of azole-resistant invasive aspergillosis in HSCT recipients in Germany.

OBJECTIVES: Aspergillus fumigatus is the most common agent of invasive aspergillosis (IA). In recent years, resistance to triazoles, the mainstay of IA therapy, has emerged in different countries worldwide. IA caused by azole-resistant A. fumigatus (ARAF) shows an exceedingly high mortality. In this study, IA due to ARAF isolates in HSCT recipients in Germany was investigated. METHODS: The epidemiology of azole resistance in IA was analysed in two German haematology departments. Between 2012 and 2013, 762 patients received HSCT in Essen (n = 388) and Cologne (n = 374). Susceptibility testing of A. fumigatus isolates was performed by Etest, followed by EUCAST broth microdilution testing if elevated MICs were recorded. In all ARAF isolates the cyp51A gene was sequenced and the genotype was determined by microsatellite typing using nine short tandem repeats. RESULTS: In total, A. fumigatus was recovered from 27 HSCT recipients. Eight patients had azole-resistant IA after HSCT, and seven of the cases were fatal (88%). All except one patient received antifungal prophylaxis (in five cases triazoles). TR34/L98H was the most common mutation (n = 5), followed by TR46/Y121F/T289A (n = 2). In one resistant isolate no cyp51A mutation was detected. Genotyping revealed genetic diversity within the German ARAF isolates and no clustering with resistant isolates from the Netherlands, India and France. CONCLUSIONS: This report highlights the emergence of azole-resistant IA with TR34/L98H and TR46/Y121F/T289A mutations in HSCT patients in Germany and underscores the need for systematic antifungal susceptibility testing of A. fumigatus.

Validation of a novel real-time PCR for detecting Rasamsonia argillacea species complex in respiratory secretions from cystic fibrosis patients.

Members of the recently introduced fungal genus Rasamsonia (formerly included in the Geosmithia genus) have been described as emerging pathogens in immunosuppressed hosts or patients with cystic fibrosis (CF). Rasamsonia species have often been misidentified as Penicillium or Paecilomyces because of similar morphological characteristics. We validated a commercially available real-time PCR assay (Primerdesign™, UK) for accurate detection of species from the Rasamsonia argillacea complex. First, we tested this assay with a collection of 74 reference strains and clinical isolates and then compared the PCR with cultures of 234 respiratory samples from 152 patients with CF from two University Hospitals in Germany and France. The assay reliably detected the three main species within the Rasamsonia argillacea species complex (R. argillacea, R. piperina, R. aegroticola), which are typically encountered in CF patients. The limit of DNA detection was between 0.01 and 1 pg/µL. Analysis of the DNA extracts from respiratory specimens of CF patients revealed that four out of the 153 patients studied (2.6%) were colonized with R. argillacea species complex. Two species from the R. argillacea complex grew in the parallel cultures from the same patients. In one patient the PCR was positive 5 months before culture. The real-time PCR assay is a sensitive and specific method for detecting the three most important species of the R. argillacea species complex encountered in the CF context. Detection of these emerging pathogens in respiratory secretions from CF patients by this novel assay may increase our understanding of the occurrence and epidemiology of the R. argillacea species complex.

Adaptation of Stenotrophomonas maltophilia in cystic fibrosis: molecular diversity, mutation frequency and antibiotic resistance.

Due to the continuous exposure to a challenging environment and repeated antibiotic treatment courses, bacterial populations in cystic fibrosis (CF) patients experience selective pressure causing the emergence of mutator phenotypes. In this study we investigated the genotypic diversity, mutation frequency and antibiotic resistance of S. maltophilia isolates chronically colonizing CF patients. S. maltophilia was isolated from a total of 90 sputum samples, collected sequentially from 19 CF patients admitted between January 2008 and March 2012 at the University Hospital Essen, Germany. DNA fingerprinting by repetitive-sequence-based PCR revealed that 68.4% (n=13) of CF patients harbored different S. maltophilia genotypes during the 4-year study course. Out of 90 S. maltophilia isolates obtained from chronically colonized CF patients, 17.8% (n=16) were hypomutators, 27.7% (n=25), normomutators, 23.3% (n=21), weak hypermutators and 31.2% (n=28) strong hypermutators. We also found that mutation rates of the most clonally related genotypes varied over time with the tendency to become less mutable. Mutator isolates were found to have no significant increase in resistance against eight different antibiotics versus nonmutators. Sequencing of the mismatch repair genes mutL, mutS and uvrD revealed alterations that resulted in amino acid changes in their corresponding proteins. Here, we could demonstrate that several different S. maltophilia genotypes are present in CF patients and as a sign of adaption their mutation status switches over time to a less mutator phenotype without increasing resistance. These results suggest that S. maltophilia attempts to sustain its biological fitness as mechanism for long-term persistence in the CF lung.

[Outbreak with Ralstonia pickettii caused by contaminated magnesium vials]. / Ausbruch mit Ralstonia pickettii durch kontaminierte Magnesium-Ampullen.

HISTORY: In February 2013, 5 patients in an intensive care unit (ICU) were found to have positive blood cultures with Ralstonia pickettii within one week. Because all patients got intravenous therapy, improper work of a staff member was suspected. Some days later, a 6th patient was found with a positive blood culture of Ralstonia pickettii in another department of the hospital. INVESTIGATIONS: Hygienic investigations showed no evidence of failures in preparation of intravenous therapy. All patients were on different intravenous drugs, but every patient had received glucose 5 % and magnesium. We examined samples of glucose and magnesia as well as samples from environment. RESULTS AND COURSE: Glucose and magnesium samples were examined by membrane filter method. Ralstonia pitteckii was detected in some Magnesium vials. We concluded, that contamination of Magnesium vials might have been the reason for blood stream infection of patients. Pharmacists and authorities were informed and all vials were collected and replaced by vials from another company. Later a nationwide recall of Magnesium vials was performed by the producing company. No further Ralstonia pickettii was found in blood cultures in our hospital. CONCLUSION: Unusual pathogens in blood cultures should lead to reflection of rarer causes such as contamination of medicines.

Value of multiplex PCR using cerebrospinal fluid for the diagnosis of ventriculostomy-related meningitis in neurosurgery patients.

PURPOSE: This prospective observational cohort study assessed the use of a multiplex real-time polymerase chain reaction (PCR) assay alone and in conjunction with biomarkers for the diagnosis of ventriculostomy-related meningitis in neurosurgery intensive care unit (ICU) patients with external ventricular drainage (EVD). METHODS: Concentrations of intrathecal biomarkers, including lactate and interleukin 6 (IL-6), were measured, and cerebrospinal fluid (CSF) was examined microbiologically by blood culture BACTEC bottles in 62 CSF samples from 41 patients with EVD. A portion of each sample was also tested with a commercially available PCR assay that simultaneously detects 25 species of bacteria and fungi [SeptiFast (SF)]. Receiver operating characteristic curve analysis was used to compare biomarker concentrations with SF and culture results. RESULTS: Seventeen (27 %) samples tested positive and 40 (65 %) tested negative for pathogens by both culture and SF. One pathogen was detected only by SF. Four samples tested positive by culture but negative by SF; in 3 of these, the isolates were considered to be contaminants. In comparison to CSF culture SF showed a larger area under the curve for IL-6 (0.90; 95 % CI 0.83-0.98) versus 0.70 (95 % CI 0.46-0.80) and for lactate (0.77; 95 % CI 0.63-0.93) versus 0.65 (95 % CI 0.50-0.80). In 94 % (17/18) of positive SF samples the results were obtained on the same day whereas the overall mean of the time-to-positivity of BACTEC bottles was 21.6 h. CONCLUSIONS: The diagnosis of EVD-related ventriculo-meningitis in neurosurgical ICU patients can be established in a rapid manner using a multiplex PCR assay on CSF samples in combination with intrathecal biomarkers.

Development of a quantitative immunofluorescence assay for detection of Stenotrophomonas maltophilia antibodies in patients with cystic fibrosis.

BACKGROUND: To describe a simple quantitative immunofluorescence assay (IFA) for the detection of specific Stenotrophomonas maltophilia antibodies in serum of CF patients. METHODS: A total of 100 sera (64 CF patients and 36 healthy subjects) were collected over a period of 2 years at the University Hospital Essen, Germany. Sputum culture status classified CF patients into groups. Serologic response was determined after Pseudomonas aeruginosa absorption by indirect IFA to Sm whole cell. RESULTS: CF patients with "chronic S. maltophilia" showed significantly higher S. maltophilia antibody levels compared with healthy individuals (P<0.0001) and CF patients with "intermittent" (P=0.0315) or "never S. maltophilia/P. aeruginosa" (P=0.0002). A discriminant cut-off value of >1:120 titre was established to differentiate "CF chronic S. maltophilia" from the other groups. For "CF chronic S. maltophilia", the IFA showed sensitivity and specificity values of 70.7% and 84.7%, respectively. CONCLUSION: Our data demonstrated that quantitative IFA is a simple serological assay for the detection of specific S. maltophilia antibodies, which could be useful as a diagnostic tool for monitoring immune response of CF patients to S. maltophilia.

Anti-infective properties of epigallocatechin-3-gallate (EGCG), a component of green tea.

The consumption of green tea (Camellia sinensis) has been shown to have many physiological and pharmacological health benefits. In the past two decades several studies have reported that epigallocatechin-3-gallate (EGCG), the main constituent of green tea, has anti-infective properties. Antiviral activities of EGCG with different modes of action have been demonstrated on diverse families of viruses, such as Retroviridae, Orthomyxoviridae and Flaviviridae and include important human pathogens like human immunodeficiency virus, influenza A virus and the hepatitis C virus. Furthermore, the molecule interferes with the replication cycle of DNA viruses like hepatitis B virus, herpes simplex virus and adenovirus. Most of these studies demonstrated antiviral properties within physiological concentrations of EGCG in vitro. In contrast, the minimum inhibitory concentrations against bacteria were 10-100-fold higher. Nevertheless, the antibacterial effects of EGCG alone and in combination with different antibiotics have been intensively analysed against a number of bacteria including multidrug-resistant strains such as methicillin-resistant Staphylococcus aureus or Stenotrophomonas maltophilia. Furthermore, the catechin EGCG has antifungal activity against human-pathogenic yeasts like Candida albicans. Although the mechanistic effects of EGCG are not fully understood, there are results indicating that EGCG binds to lipid membranes and affects the folic acid metabolism of bacteria and fungi by inhibiting the cytoplasmic enzyme dihydrofolate reductase. This review summarizes the current knowledge and future perspectives on the antibacterial, antifungal and antiviral effects of the green tea constituent EGCG.

In vitro activity of colistin as single agent and in combination with antifungals against filamentous fungi occurring in patients with cystic fibrosis.

Because published reports indicate that the antibiotic colistin (COL) has antifungal properties, this study investigated the antifungal in vitro activity of COL as single agent and in combination with the antifungal compounds voriconazole (VRC), caspofungin (CAS) and amphotericin B (AMB) against Scedosporium/Pseudallescheria spp., Exophiala dermatitidis and Geosmithia argillacea. In total, susceptibility was determined for 77 Scedosporium/Pseudallescheria spp., 82 E. dermatitidis and 17 G. argillacea isolates. The minimal inhibitory concentrations (MICs) of COL and the antifungals as single compound and in combination were determined with MIC test strips. Drug interactions were detected by crossing the MIC test strips at a 90º angle. The fractional inhibitory concentration index was used to categorise the drugs' interaction. The MIC50 value of COL was 12 µg ml(-1) for S. prolificans, 16 µg ml(-1) for P. apiosperma, 16 µg ml(-1) for P. boydii, 12 µg ml(-1) for E. dermatiditis and 6 µg ml(-1) for G. argillacea. VRC was the most active drug in combination without any antagonism with the exception of few P. boydii isolates. COL as single agent and in most combinations with antifungals exhibits in vitro antifungal activity against filamentous ascomycetes occurring in cystic fibrosis patients and may offer a novel therapeutic option, especially for multidrug-resistant S. prolificans.