Impairment of the Bacterial Biofilm Stability by Triclosan

The accumulation of the widely-used antibacterial and antifungal compound triclosan (TCS) in freshwaters raises concerns about the impact of this harmful chemical on the biofilms that are the dominant life style of microorganisms in aquatic systems. However, investigations to-date rarely go beyond effects at the cellular, physiological or morphological level. The present paper focuses on bacterial biofilms addressing the possible chemical impairment of their functionality, while also examining their substratum stabilization potential as one example of an important ecosystem service. The development of a bacterial assemblage of natural composition – isolated from sediments of the Eden Estuary (Scotland, UK) – on non-cohesive glass beads (,63 mm) and exposed to a range of triclosan concentrations (control, 2 – 100 mg L21) was monitored over time by Magnetic Particle Induction (MagPI). In parallel, bacterial cell numbers, division rate, community composition (DGGE) and EPS (extracellular polymeric substances: carbohydrates and proteins) secretion were determined. While the triclosan exposure did not prevent bacterial settlement, biofilm development was increasingly inhibited by increasing TCS levels. The surface binding capacity (MagPI) of the assemblages was positively correlated to the microbial secreted EPS matrix. The EPS concentrations and composition (quantity and quality) were closely linked to bacterial growth, which was affected by enhanced TCS exposure. Furthermore, TCS induced significant changes in bacterial community composition as well as a significant decrease in bacterial diversity. The impairment of the stabilization potential of bacterial biofilm under even low, environmentally relevant TCS levels is of concern since the resistance of sediments to erosive forces has large implications for the dynamics of sediments and associated pollutant dispersal. In addition, the surface adhesive capacity of the biofilm acts as a sensitive measure of ecosystem effects

Pneumocystis jirovecii genotype associated with increased death rate of HIV-infected patients with pneumonia.

Pneumocystis jirovecii dihydropteroate synthase (DHPS) mutations have been associated with failure of sulfa prophylaxis; their effect on the outcome of patients with P. jirovecii pneumonia (PCP) remains controversial. P. jirovecii DHPS polymorphisms and genotypes were identified in 112 cases of PCP in 110 HIV-infected patients by using PCR single-strand conformation polymorphism. Of the 110 patients observed, 21 died; 18 of those deaths were attributed to PCP. Thirty-three percent of the PCP cases involved a P. jirovecii strain that had 1 or both DHPS mutations. The presence or absence of DHPS mutations had no effect on the PCP mortality rate within 1 month, whereas P.jirovecii type 7 and mechanical ventilation at PCP diagnosis were associated with an increased risk of death caused by PCP. Mechanical ventilation at PCP diagnosis was also associated with an increased risk of sulfa treatment failure at 5 days.

Impact of antiviral preventive strategies on the incidence and outcomes of cytomegalovirus disease in solid organ transplant recipients.

We assessed the impact of antiviral prophylaxis and preemptive therapy on the incidence and outcomes of cytomegalovirus (CMV) disease in a nationwide prospective cohort of solid organ transplant recipients. Risk factors associated with CMV disease and graft failure-free survival were analyzed using Cox regression models. One thousand two hundred thirty-nine patients transplanted from May 2008 until March 2011 were included; 466 (38%) patients received CMV prophylaxis and 522 (42%) patients were managed preemptively. Overall incidence of CMV disease was 6.05% and was linked to CMV serostatus (D+/R- vs. R+, hazard ratio [HR] 5.36 [95% CI 3.14-9.14], pâeuro0/00<âeuro0/000.001). No difference in the incidence of CMV disease was observed in patients receiving antiviral prophylaxis as compared to the preemptive approach (HR 1.16 [95% CI 0.63-2.17], pâeuro0/00=âeuro0/000.63). CMV disease was not associated with a lower graft failure-free survival (HR 1.27 [95% CI 0.64-2.53], pâeuro0/00=âeuro0/000.50). Nevertheless, patients followed by the preemptive approach had an inferior graft failure-free survival after a median of 1.05 years of follow-up (HR 1.63 [95% CI 1.01-2.64], pâeuro0/00=âeuro0/000.044). The incidence of CMV disease in this cohort was low and not influenced by the preventive strategy used. However, patients on CMV prophylaxis were more likely to be free from graft failure.

Diagnostic and identification in situ of fungal pathogens in superficial mycosis

Fungi are divided in 3 groups in the field of medical mycology. The dermatophytes are filamentous fungi able to grow on keratinized tissues from human or animals. They are the main cause of superficial and cutaneous mycoses of the skin and its appendix (hair and nail). The yeasts, or dimorphic fungi, can be responsible of diverse types of infections (superficial to deep mycoses). The moulds include all Non-dermatophyte Filamentous Fungi (NDF). In medical mycology, the most representative moulds are Aspergillus spp., Fusarium spp. and Mucor spp. Diagnosis of mycosis is currently based on direct mycological examination of biological samples, as well as macroscopic and microscopic identification of the infectious fungus in culture assay. However, culture assays were found to remain sterile in roughly 40% of cases otherwise positive by direct mycological examinations. Additionally, results from culture assays are often difficult to interpret as various NDF are sometimes isolated. This thesis work is composed of three projects focusing on the development of new assays for direct in situ identification of fungi from dermatological samples. Part 1. A Polymerase Chain Reaction - Terminal Restriction Fragment Length Polymorphism assay (PCR-TRFLP) targeting the 28S rDNA was developed to identify dermatophytes and NDF in nails with suspected onychomycosis. This method is faster and more efficient than culture. It further enables the distinction of more than one agent in case of mixed infection. A fast and reliable assay for the identification of dermatophytes and NDF in onychomycosis was found to be highly relevant since onychomycosis with Fusarium spp. or other NDF are weakly responsive or unresponsive to standard onychomycosis treatments with oral terbinafine and itraconazole. Part 2. A nested PCR-sequencing assay targeting the 28S rDNA was developed to identify dermatophyte species in skin and hair samples. This method is especially suitable for tinea capitis where dermatophytes identification is critical for subsequently prescribing the adequate treatment. The challenge presented when performing direct PCR fungi identification in skin and hair differs from that seen in onychomycosis as small amount of material is generally collected, few fungal elements are present in the clinical sample and one dermatophyte among a dozen species must be identified. Part 3. Fusarium spp. is currently isolated from nails with a frequency of 15% of that of dermatophytes in the laboratory of Mycology of the CHUV (2005-2012). The aim of this work was to examine if the intensive use of terbinafine and itraconazole could be a cause of the high incidence of Fusarium nail infections. For that purpose, two different methods, specific PCR and TRFLP, were used to detect both Fusarium spp. and Trichophyton spp. in nails of previously treated or untreated patients. TRFLP assay was found to be less sensitive than classical PCR assays specifically detecting Fusarium spp. or Trichophyton spp. Independently of the detection method used, the prevalence of Fusarium spp. appears not to be higher in patients previously treated by oral standard treatment with terbinafine and azoles which are highly effective to fight Trichophyton spp. in nails. In many cases Fusarium sp. was detected in samples of patients not previously subjected to antifungal therapy. Therefore, these treatments do not appear to favor the establishment of Fusarium spp. after elimination of a dermatophyte in nail infection. - En mycologie médicale, les champignons sont classés en 3 groupes. Les dermatophytes sont des champignons filamenteux capables de se développer dans les tissus kératinisés des hommes et des animaux, ils représentent la principale cause des mycoses superficielles et cutanées de la peau et de ses appendices (ongles et cheveux). Les levures, ou champignons dimorphiques, peuvent être responsables de divers types d'infections (superficielles à profondes). Les moisissures incluent tous les champignons filamenteux non-dermatophytes (NDF), les Aspergillus spp., les Fusarium spp. et les Mucor spp. sont les principales espèces rencontrées. Le diagnostic d'une mycose est basé sur un examen mycologique direct des prélèvements biologiques ainsi que sur l'identification macroscopique et microscopique du champignon infectieux isolé en culture. Cependant, dans environ 40% des cas, l'identification de l'agent pathogène est impossible par cette méthode car la culture reste stérile, bien que l'examen direct soit positif. De plus, la croissance de moisissures et/ou autres contaminants peut rendre l'interprétation de l'examen difficile. Ce travail de thèse est composé de trois projets focalisés sur le développement de nouvelles méthodes d'identification des champignons directement à partir d'échantillons dermatologiques. Projet 1. Une méthode de Réaction en chaîne de polymérase couplée à du polymorphisme de longueur des fragments de restriction terminaux (PCR-TRFLP), en ciblant l'ADN ribosomal 28S, a été développée pour l'identification des dermatophytes et moisissures dans les ongles avec suspicion d'onychomycoses. Cette technique s'est avérée plus rapide et plus efficace que la culture, permettant l'identification de plusieurs champignons en même temps. Posséder une méthode d'identification rapide et fiable des dermatophytes et des NDF dans les onychomycoses a été jugée nécessaire du fait que les Fusarium et d'autres NDF sont peu ou pas sensibles aux traitements oraux standards à la terbinafine et à Γ itraconazole. Projet 2. Une PCR nichée couplée au séquençage d'un fragment de l'ADN ribosomal 28S a été développée afin de différencier les dermatophytes dans la peau et les cheveux. Cette méthode est particulièrement adaptée au cas de tinea capitis, où l'identification du dermatophyte est essentielle afin de prescrire le traitement adéquat. Le problème de l'identification du pathogène fongique dans les cheveux et la peau diffère des onychomycoses car de petites quantités sont prélevées chez les patients, peu d'éléments fongiques sont présents et il faut discriminer un dermatophyte parmi une douzaine d'espèces potentielles. Projet 3. Au laboratoire de Mycologie du CHUV, les Fusarium ont été isolé dans les ongles à une fréquence de 15% pour la période 2005-2012. Le but de ce travail était d'examiner si l'utilisation intensive de terbinafine et d'itraconazole pouvait être une des causes de la forte incidence des infections des ongles par Fusarium. A cet effet, deux méthodes ont été utilisées pour détecter à la fois Fusarium spp. et Trichophyton spp., la PCR spécifique et le TRFLP. Indépendamment de la méthode choisie, il en résulte que la prévalence des Fusarium η'apparaît pas liée à un traitement au préalable des patients avec de la terbinafine ou des azoles, thérapies très efficaces contre les Trichophyton spp. dans les ongles. De plus, il existe de nombreux cas où Fusarium était détecté chez des patients non traités.

Prevalence and time course of acute mountain sickness in older children and adolescents after rapid ascent to 3450 meters

OBJECTIVE: Acute mountain sickness is a frequent and debilitating complication of high-altitude exposure, but there is little information on the prevalence and time course of acute mountain sickness in children and adolescents after rapid ascent by mechanical transportation to 3500 m, an altitude at which major tourist destinations are located throughout the world. METHODS: We performed serial assessments of acute mountain sickness (Lake Louise scores) in 48 healthy nonacclimatized children and adolescents (mean +/- SD age: 13.7 +/- 0.3 years; 20 girls and 28 boys), with no previous high-altitude experience, 6, 18, and 42 hours after arrival at the Jungfraujoch high-altitude research station (3450 m), which was reached through a 2.5-hour train ascent. RESULTS: We found that the overall prevalence of acute mountain sickness during the first 3 days at high altitude was 37.5%. Rates were similar for the 2 genders and decreased progressively during the stay (25% at 6 hours, 21% at 18 hours, and 8% at 42 hours). None of the subjects needed to be evacuated to lower altitude. Five subjects needed symptomatic treatment and responded well. CONCLUSION: After rapid ascent to high altitude, the prevalence of acute mountain sickness in children and adolescents was relatively low; the clinical manifestations were benign and resolved rapidly. These findings suggest that, for the majority of healthy nonacclimatized children and adolescents, travel to 3500 m is safe and pharmacologic prophylaxis for acute mountain sickness is not needed.

Lapatax: Safety profile of neoadjuvant lapatinib combined with docetaxel in Her 2/neu overexpressing breast cancer - EORTC protocol 10054

Objective: To assess the safety/tolerability of the combination lapatinib (L) and docetaxel (D) in patients with Her 2/neu overexpressing breast cancer (BC). This study is important as it will define how to deliver lapatinib with taxotere, a highly active drug in breast cancer. Patients and Methods: Female patients (pts) with locally advanced, inflammatory or large operable BC were treated with escalating doses of L from 1000 to 1250 mg/day, in combination with D given IV every 21 days at doses ranging from 75 to 100 mg/m2 for 4 cycles. At least 3 pts were treated at each dose level. The definition of dose limiting toxicity (DLT) is based on the toxicity assessed at cycle 1 as follows: any grade 3−4 non hematological toxicity, ANC < 0.5 G/L lasting for 7 days or more, febrile neutropenia or thrombocytopenia <25 G/L. GCSF was not permitted as primary prophylaxis. Core biopsies were mandatory at baseline and after cycle 4. Pharmcokinetic (PK) samples were collected on day 1 of cycles 1 and 2. Results: To date, 18 pts with a median age of 53 years (range 36−65) have been enrolled at 5 Dose Levels (DLs). The toxicity profile for 18 patients (68 documented cycles) is summarized below. At DL5 (1000/100), 2 pts had DLTs (neutropenia grade 4 _7 days and febrile neutropenia), and 3 additional pts were enrolled with primary prophylactic G-CSF. As expected, the safety profile improved and the dose escalation will continue with prophylactic G-CSF to investigate DL6 (1250/100). These findings are consistent with published Phase I data for this combination [1]. N= 18 patients n (%) Grade 1 Grade 2 Grade 3 Grade 4 neutropenia 1 (6) 3 (17) 13 (72) febrile neutropenia 2 (11) fatigue 8 (44) 7 (39) diarrhoea 9 (50) 3 (17) pain: joint/muscle/other 5 (28)/4 (22)/3 (17) 4 (22)/4 (22)/3 (17) 0/0/1 (6) constipation 2 (11) 3 (17) 1 (6) elevated transaminases SGPT/SGOT 7 (39)/5 (28) Conclusions: The main toxicity of the L + D combination is haematological and was reached at DL5 (1000/100), without primary GCSF. An additional DL6 with primary prophylactic GCSF is being investigated (1250/100). PK data will be presented at the meeting plus the recommended dose for phase II studies.

Detailed analysis and follow-up studies of a high-throughput screening for indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors.

Indoleamine 2,3-dioxygenase 1 (IDO1) is a key regulator of immune responses and therefore an important therapeutic target for the treatment of diseases that involve pathological immune escape, such as cancer. Here, we describe a robust and sensitive high-throughput screen (HTS) for IDO1 inhibitors using the Prestwick Chemical Library of 1200 FDA-approved drugs and the Maybridge HitFinder Collection of 14,000 small molecules. Of the 60 hits selected for follow-up studies, 14 displayed IC50 values below 20 μM under the secondary assay conditions, and 4 showed an activity in cellular tests. In view of the high attrition rate we used both experimental and computational techniques to identify and to characterize compounds inhibiting IDO1 through unspecific inhibition mechanisms such as chemical reactivity, redox cycling, or aggregation. One specific IDO1 inhibitor scaffold, the imidazole antifungal agents, was chosen for rational structure-based lead optimization, which led to more soluble and smaller compounds with micromolar activity.

Impact of enterococcal colonization and infection in solid organ transplantation recipients from the Swiss Transplant Cohort Study.

BACKGROUND: The burden of enterococcal infections has increased over the last decades with vancomycin-resistant enterococci (VRE) being a major health problem. Solid organ transplantation is considered as a risk factor. However, little is known about the relevance of enterococci in solid organ transplantation recipients in areas with a low VRE prevalence. METHODS: We examined the epidemiology of enterococcal events in patients followed in the Swiss Transplant Cohort Study between May 2008 and September 2011 and analyzed risk factors for infection, aminopenicillin resistance, treatment, and outcome. RESULTS: Of the 1234 patients, 255 (20.7%) suffered from 392 enterococcal events (185 [47.2%] infections, 205 [52.3%] colonizations, and 2 events with missing clinical information). Only 2 isolates were VRE. The highest infection rates were found early after liver transplantation (0.24/person-year) consisting in 58.6% of Enterococcus faecium. The highest colonization rates were documented in lung transplant recipients (0.33/person-year), with 46.5% E. faecium. Age, prophylaxis with a betalactam antibiotic, and liver transplantation were significantly associated with infection. Previous antibiotic treatment, intensive care unit stay, and lung transplantation were associated with aminopenicillin resistance. Only 4/205 (2%) colonization events led to an infection. Adequate treatment did not affect microbiological clearance rates. Overall mortality was 8%; no deaths were attributable to enterococcal events. CONCLUSIONS: Enterococcal colonizations and infections are frequent in transplant recipients. Progression from colonization to infection is rare. Therefore, antibiotic treatment should be used restrictively in colonization. No increased mortality because of enterococcal infection was noted.

Azole resistance by loss of function of the sterol Δ⁵,⁶-desaturase gene (ERG3) in Candida albicans does not necessarily decrease virulence.

The inactivation of ERG3, a gene encoding sterol Δ⁵,⁶-desaturase (essential for ergosterol biosynthesis), is a known mechanism of in vitro resistance to azole antifungal drugs in the human pathogen Candida albicans. ERG3 inactivation typically results in loss of filamentation and attenuated virulence in animal models of disseminated candidiasis. In this work, we identified a C. albicans clinical isolate (VSY2) with high-level resistance to azole drugs in vitro and an absence of ergosterol but normal filamentation. Sequencing of ERG3 in VSY2 revealed a double base deletion leading to a premature stop codon and thus a nonfunctional enzyme. The reversion of the double base deletion in the mutant allele (erg3-1) restored ergosterol biosynthesis and full fluconazole susceptibility in VSY2, confirming that ERG3 inactivation was the mechanism of azole resistance. Additionally, the replacement of both ERG3 alleles by erg3-1 in the wild-type strain SC5314 led to the absence of ergosterol and to fluconazole resistance without affecting filamentation. In a mouse model of disseminated candidiasis, the clinical ERG3 mutant VSY2 produced kidney fungal burdens and mouse survival comparable to those obtained with the wild-type control. Interestingly, while VSY2 was resistant to fluconazole both in vitro and in vivo, the ERG3-derived mutant of SC5314 was resistant only in vitro and was less virulent than the wild type. This suggests that VSY2 compensated for the in vivo fitness defect of ERG3 inactivation by a still unknown mechanism(s). Taken together, our results provide evidence that contrary to previous reports inactivation of ERG3 does not necessarily affect filamentation and virulence.

Cell-mediated immunity to predict cytomegalovirus disease in high-risk solid organ transplant recipients.

Late-onset cytomegalovirus (CMV) disease commonly occurs after discontinuation of antiviral prophylaxis. We determined the utility of testing CD8+ T-cell response against CMV as a predictor of late-onset CMV disease after a standard course of antiviral prophylaxis. Transplant patients at high-risk for CMV disease were enrolled. CD8+ T-cell-mediated immunity (CMI) was tested using the QuantiFERON-CMV assay at baseline, 1, 2 and 3 months posttransplant by measurement of interferon-gamma response to whole blood stimulation with a 21-peptide pool. The primary outcome was the ability of CMI testing to predict CMV disease in the first 6 months posttransplant. There were 108 evaluable patients (D+/R+ n = 39; D-/R+ n = 34; D+/R- n = 35) of whom 18 (16.7%) developed symptomatic CMV disease. At the end of prophylaxis, CMI was detectable in 38/108 (35.2%) patients (cutoff 0.1 IU/mL interferon-gamma). CMV disease occurred in 2/38 (5.3%) patients with a detectable interferon-gamma response versus 16/70 (22.9%) patients with a negative response; p = 0.038. In the subgroup of D+/R- patients, CMV disease occurred in 1/10 (10.0%) patients with a detectable interferon-gamma response (cutoff 0.1 IU/mL) versus 10/25 (40.0%) patients with a negative CMI, p = 0.12. Monitoring of CMI may be useful for predicting late-onset CMV disease.

ECIL-3 classical diagnostic procedures for the diagnosis of invasive fungal diseases in patients with leukaemia.

Invasive fungal diseases (IFDs) continue to cause considerable morbidity and mortality in patients with haematological malignancy. Diagnosis of IFD is difficult, with the sensitivity of the gold standard tests (culture and histopathology) often reported to be low, which may at least in part be due to sub-optimal sampling or subsequent handling in the routine microbiological laboratory. Therefore, a working group of the European Conference in Infections in Leukaemia was convened in 2009 with the task of reviewing the classical diagnostic procedures and providing recommendations for their optimal use. The recommendations were presented and approved at the ECIL-3 conference in September 2009. Although new serological and molecular tests are examined in separate papers, this review focuses on sample types, microscopy and culture procedures, antifungal susceptibility testing and imaging. The performance and limitations of these procedures are discussed and recommendations are provided on when and how to use them and how to interpret the results.

Nonmolecular methods for the diagnosis of respiratory fungal infections.

Diagnosis of invasive fungal pneumonias by conventional culture methods is difficult to assess and often delayed. Nonmolecular fungal markers have emerged as an important adjunctive tool to support their diagnosis in combination with other clinical, radiologic, and microbiological criteria of invasive fungal diseases. Concerns about the sensitivity and specificity of some tests in different patient populations should lead to warnings about their widespread use. None can identify the emerging and particularly deadly fungal pathogens responsible for mucormycosis. The role of nonmolecular fungal markers should be better defined in combination with other microbiological and radiologic tools in preemptive antifungal strategies.

Evaluation of a polymerase chain reaction-restriction fragment length polymorphism assay for dermatophyte and nondermatophyte identification in onychomycosis.

BACKGROUND: Dermatophytes are the main cause of onychomycoses, but various nondermatophyte filamentous fungi are often isolated from abnormal nails. The correct identification of the aetiological agent of nail infections is necessary in order to recommend appropriate treatment. OBJECTIVE: To evaluate a rapid polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay based on 28S rDNA for fungal identification in nails on a large number of samples in comparison with cultures. METHODS: Infectious fungi were analysed using PCR-RFLP in 410 nail samples in which fungal elements were observed in situ by direct mycological examination (positive samples). The results were compared with those previously obtained by culture of fungi on Sabouraud agar from the same nail samples. RESULTS: PCR-RFLP identification of fungi in nails allowed validation of the results obtained in culture when Trichophyton spp. grew from infected samples. In addition, nondermatophyte filamentous fungi could be identified with certainty as the infectious agents in onychomycosis, and discriminated from dermatophytes as well as from transient contaminants. The specificity of the culture results relative to PCR-RFLP appeared to be 81%, 71%, 52% and 63% when Fusarium spp., Scopulariopsis brevicaulis, Aspergillus spp. and Candida spp., respectively, grew on Sabouraud agar. It was also possible to identify the infectious agent when direct nail mycological examination showed fungal elements, but negative results were obtained from fungal culture. CONCLUSIONS: Improved sensitivity for the detection of fungi in nails was obtained using the PCR-RFLP assay. Rapid and reliable molecular identification of the infectious fungus can be used routinely and presents several important advantages compared with culture in expediting the choice of appropriate antifungal therapy.

Candida : quand traiter, comment et pourquoi ? [Candida: when to treat, how and why?]

Grevées d'une mortalité comparable à celle du choc septique (40%-60%), les candidoses invasives sont une complication nosocomiale rare, mais particulièrement redoutée. Elles sont cependant difficiles à diagnostiquer, car si près de 50% des patients sont colonisés par des levures du genre Candida au cours d'un séjour prolongé en réanimation, seule une minorité d'entre eux développent une candidose sévère. En dehors des cas de candidémie, aucun test diagnostique ne permet de distinguer les patients colonisés de ceux qui sont infectés. Chez les patients présentant des facteurs de risque, la pratique de cultures de surveillance systématiques permet de déceler précocement une colonisation et d'en quantifier le degré. Un traitement préemptif peut être envisagé lorsque le degré de colonisation dépasse un seuil critique prédictif d'infection. De nouvelles classes d'antifongiques sont sur le point de révolutionner les schémas thérapeutiques actuels.