Impact of portable air filtration units on exposure of haematology-oncology patients to airborne Aspergillus fumigatus spores under field conditions

We undertook a one-year study to investigate the impact of the NSA model 7100A/B portable air filtration unit on exposure of haematology-oncology patients to airborne Aspergillus fumigatus spores under field conditions. Weekly measurements for airborne A. fumigatus were conducted in indoor and outdoor air, and surveillance for invasive aspergillosis was based on a combination of ward liaison, targeted chart review and consultation with the medical staff. The mean indoor A. fumigatus counts (8.1 cfu/m3; range, <0.8 to 42 cfu/m3) reflected the fungal load of outdoor air (9.4 cfu/m3; range, <0.8 to 50 cfu/m3), and were reduced by only about one third in rooms with portable air filtration units (5.3 cfu/m3; range, <0.8 to 41 cfu/m3). During the study period, a total of five cases (incidence density, 0.8 per 1000 patient-days) of invasive aspergillosis (one proven case, four suspected cases; case fatality rate 40%) were recorded. None of these five patients was allocated to a room with portable air filtration unit, however, the difference between incidence densities in rooms with and without portable air filtration units was non-significant (Fisher's exact test, P=0.33). Due to the noise level and thermal discomfort, patient compliance with the air filtration units was poor. We conclude that under field conditions this air filtration unit cannot be recommended for prevention of invasive aspergillosis in neutropenic haematology-oncology patients.     

Studies on the epidemiology of Aspergillus fumigatus infections in a university hospital

The impact of the airborne opportunistic fungus pathogen, Aspergillus fumigatus in patients hospitalized at the university hospital of Parma, Italy, and its outpatients was investigated during a period of six months. Sputum and bronchial washings were collected from 986 patients. The 2,437 specimens were culturally examined for the presence of A. fumigatus regardless of the patient's clinical diagnosis. This fungus was isolated from 32 patients (3.2%). Subsequently, immunological tests for aspergillosis were performed on 22 of these culture-positive patients. Eight of these patients (36.4%) were serologically proven to be affected by aspergillosis. The 32 A. fumigatus isolates were epidemiologically investigated by the killer system to determine the mode of spread of these infections. Among the patients, fifteen different biotypes were differentiated, and their value in studying the epidemiology of aspergillosis in the hospital environment was investigated.Corresponding author.     

Species identification and detection of oxacillin resistance in coagulase-negative Staphylococcus blood isolates from neutropenic patients

One hundred coagulase-negative staphylococcal isolates from septicemic neutropenic patients with hematologic malignancies were identified to a species level by means of the French API STAPH strip system and by the Automicrobic VITEK system. According to these two methods, which concurred in 95% of cases, S. epidermidis (80–82% of the isolates) was the most frequently identified species, followed by S. haemolyticus (6–7% of the isolates). The susceptibility to oxacillin was also evaluated by macrodilution MIC, Automicrobic VITEK system and agar screen, and 76,78 and 79 of the 100 isolates, respectively, were found resistant to this antibiotic. All oxacillin-resistant isolates according to Automicrobic VITEK were confirmed resistant by agar screen. A 48h incubation was required to determine oxacillin resistance in 11 of 79 isolates with agar screen and in 10 of 76 isolates with macrodilution MIC.Automicrobic VITEK system may represent a useful method for rapid identification to a species level and early recognition of oxacillin resistance in coagulase-negative staphylococci.Corresponding author.     

Fungal surveillance of an open haematology ward

Air sampling and surveillance cultures for fungi were performed in a Scottish general haematology ward over a five-month period in 1997. The mean total fungal count from the air sampling appeared to be correlated with the number of patients colonized by Aspergillus. The most commonly isolated species were Aspergillus versicolor, A. fumigatus and A. niger. Rooms with portable air filtration units had significantly lower total fungal counts than the others. Swabs were taken from 70 patients (mean age 62 years); 114 of the 563 cultures (20.2%) were positive. The most commonly isolated species were A. fumigatus, Candida albicans, C. glabrata and C. parapsilosis. Samples taken from the tongue and perineum showed colonization more often than those taken from the nostrils. Almost half the patients (48.6%) were colonized on, or within seven days of, admission; 11.4% became colonized whilst on the unit. One patient developed fatal aspergillosis. We conclude that colonization or high air-borne spore concentrations are not necessarily predictive of fungal infection but may prompt early treatment or more aggressive prophylaxis of potentially fatal invasive infections.     

Bio-Separation of Toxic Arsenate Ions from Dilute Solutions by Native and Pretreated Biomass of <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> in Batch and Column Mode: Effect of Biomass Pretreatment

The sorption of As(V) from aqueous solution onto live and pretreated biomass of Aspergillus fumigatus was studied. The studies on optimization of contact time, adsorbent dosage and pH showed that the FeCl(3) treated and FeSO(4) treated biomass had the maximum capacity to adsorb As(V) while acid treated biomass was found to be minimum. Adsorption parameters were determined using both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of 0.054 mg/g was observed in FeCl(3) treated and FeSO(4) treated biomasses. Column mode studies were conducted using FeSO(4) treated biomass to compare its efficacy with batch mode to adsorb As(V). Batch mode experiments proved to be efficient. Desorption studies were also carried out with dilute sodium hydroxide to recover both the adsorbent and adsorbate.     

Spatial variations in airborne microorganism and endotoxin concentrations at green waste composting facilities

The emission and dispersal of bioaerosols from open-air commercial composting facilities continues to be contentious. A meta-dataset enumerating cultivable microorganism emission and downwind concentrations is not yet available. A dataset derived from repeated and replicated field studies over a period of two years at two commercial composting facilities is presented. The data characterises patterns in Aspergillus fumigatus, actinomycetes, Gram-negative bacteria and endotoxin emission and downwind concentrations. For all bioaerosols, compost agitation activities had a significant impact on concentrations; levels were variable up to 600 m downwind from site. Bioaerosols declined rapidly from source and exhibited a secondary peak 100–150 m from site boundary. All bioaerosols were found downwind from site in elevated concentrations. Compared to those found 100 m upwind, levels were significantly higher at 180 m downwind for A. fumigatus; at 300–400 m for actinomycetes and Gram negative bacteria, and at 100 m for endotoxins. Periodically, elevated concentrations could be found for all bioaerosols at distances further downwind. The evidence provided by this data set provides operators and regulators of facilities with reliable data to inform the location, risk assessment and bioaerosol sampling strategies of commercial composting facilities.     

烟曲霉对唑类药物耐药研究的最新进展

烟曲霉是一种重要的临床致病真菌,可引发致死性霉菌感染。唑类药物是治疗各类曲霉病的临床一线药物。近年来,全世界范围内烟曲霉对唑类药物耐药的报道不断增加,严重影响临床和农药唑类药物使用的有效性,已成为一个重要公共卫生问题。本文主要对烟曲霉唑类药物耐药的流行现状、耐药分子机制、耐药产生的原因、耐药株的进化规律以及防控措施等分别进行介绍。     

Allergic bronchopulmonary aspergillosis in Italian cystic fibrosis patients: Prevalence and percentage of positive tests in the employed diagnostic criteria

The prevalence of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients is difficult to determine because the data in the literature are not homogeneous or comparable. ABPA and CF have similar clinical symptoms which make diagnosis difficult and underestimate the real dimensions of the problem. We conducted an epidemiological study on 3089 Italian CF patients to determine the prevalence of ABPA in Italy and verify the percentage of positive tests in the employed diagnostic criteria. Our results indicate that the prevalence of ABPA in Italian CF patients is 6.18%, mainly in adolescents and young adults. ABPA is diagnosed using clinical symptoms (presence of episodic bronchial obstructions or typical radiographic features) and on the basis of other criteria which can only be partially fulfilled in paediatric patients. Among the diagnostic tests the most sensitive are the total IgE (84.5%), specific IgE anti-Aspergillus fumigatus (81.6%) and the prick test (68.3%). In the absence of clinical symptoms and gold standard diagnostic tests, serological positivity and/or the skin test are not sufficient evidence to confirm the presence of ABPA.     

Fungal colonization of haematological patients receiving cytotoxic chemotherapy: emergence of azole-resistant Saccharomyces cerevisiae

Fungal colonization during cytotoxic chemotherapy was studied in 42 patients with a recent diagnosis of a haematological malignancy. In total, 2759 surveillance cultures were taken from the nostrils, throat, urine, stool and perineal region. Seven hundred and ninety-six positive surveillance cultures (28.9%) yielded 968 fungal isolates. The rate of fungal colonization did not differ between patients with acute leukaemia, patients with other haematological malignancies and control patients in the same ward at admission (71% vs. 67% vs. 80%). Patients with acute leukaemia were colonized at a significantly lower rate in samples from the throat (32%), urine (10%), stool (45%) and perineum (29%) taken during hospitalization when compared with other haematological patients (respective values 58%, 21%, 67% and 45%; P-values 0.001). This could be attributed to differences in the use of antifungal drugs. Although 21/42 (50%) of our patients had multiple-site fungal colonization at the end of follow-up, only one systemic Candida infection was diagnosed. Extensive use of antifungal treatment may have influenced the low incidence of systemic fungal infections during the follow-up. In addition to Candida species, Malassezia furfur, Geotrichum candidum and Saccharomyces cerevisiae were frequently isolated. The rate of S. cerevisiae isolation increased significantly over time after admission (1%, vs. 18% of isolates, P<0.001), suggesting hospital-acquired transmission. These isolates were highly resistant to azole antifungals (MIC90 128 microg/mL for fluconazole and 16 microg/ml, for itraconazole), and caused persistent multiple site colonization in 12 patients. Extensive use of antifungal agents in a haematological ward may keep the incidence of invasive fungal infections low in spite of heavy fungal colonization. However, there may be a risk of emergence of resistant fungal strains.     

Fungal cell adhesion molecules in Candida albicans

Adherence of Candida albicans to host tissues is considered a crucial step in the pathogenesis of candidiasis. Using in vitro assays, it was demonstrated that the yeast — mycelium transition was an important phenomenon in the acquisition of adhesive properties. Proteins with MWs of 60, 68, 200 and > 200 kDa seemed to be involved in germ tube adherence to plastic surfaces. Likewise, recent investigations have revealed that C. albicans expresses on its surface receptors which interact with a wide variety of host proteins, particularly some extracellular matrix components like fibronectin, laminin and collagen. Plasmatic components, such as fibrinogen, iC3b and C3d, have also been proposed as mediators of adherence of C. albicans. Thus, by their reaction with laminin, fibrinogen and C3d, the mannoproteins of 68 and 60 kDa demonstrated multiple biological activities. Proteins of similar MWs were detected as C3d and iC3b receptors, the latter showing similarities with the neutrophil CR3. Based upon the antigenic, structural and functional homologies between the candidal receptors and mammalian integrins, it was postulated that these fungal cell adhesion molecules (F-CAM) are members of the integrin family. Interactions with host proteins and molecular mimicry of mammalian adhesion molecules may be a fertile area for further research.Corresponding author.     

Bacteraemia caused by non-aeruginosa Pseudomonas species in a cancer centre

Fifty-one episodes of bacteraemia due to Pseudomonas species other than Pseudomonas aeruginosa occurring between 1980 and 1990 in a Belgian cancer centre were reviewed. This corresponded to an incidence of 0.62/1000 admissions, or 1.5% of all bacteraemic episodes. Twenty-nine episodes, each with several positive blood culture sets were considered clinically significant, including six patients belonging to a well-documented outbreak of pseudobacteraemia with Xanthomonas maltophilia and associated with contaminated blood sampling tubes. The respiratory tract was the source in six (20.7%), an infected intravenous catheter in 10 (34.5%) and the source was unknown in seven (24.1%). Seven patients died from infection (24.1%). Twenty-three episodes with a single positive blood culture set were considered clinically not significant, although four of them were considered significant by the Centers for Disease Control (CDC) criteria because of the presence of symptoms and specific antibiotic treatment being administered. None of the patients with a single isolate died from infection despite the fact that 17 of 22 did not receive an effective antimicrobial agent. All isolates were susceptible to co-trimoxazole.     

Transformation of Copper Fractions in Rhizosphere Soil of Two Dominant Plants in a Deserted Land of Copper Tailings

This paper studied the transformation of copper fractions in rhizosphere and non-rhizosphere soils of Festuca arundinacea and Trifolium repens in deserted land of copper tailings. The results showed that the proportion of organic-bound or exchangeable contents to the total contents of copper in rhizosphere increased by 9.81 and 10.42%, while the contents of carbonate-bound or Fe–Mn oxides-bound decreased by 2.96 and 1.82%, respectively. The growth and absorption of F. arundinacea and T. repens accelerated the transformation of copper fractions in rhizosphere soils. The effect of root system of T. repens was prominently greater than that of F. arundinacea.     

Two sources of contamination of a hydrotherapy pool by environmental organisms

As a result of occasional water discolouration, the hydrotherapy pool of a large teaching hospital was monitored for free and combined chlorine, alkalinity, calcium hardness, total dissolved solids and cyanuric acid levels together with bacteriological analysis. The hose pipe supplying the pool and the dual water pumps were also examined as potential sources of bacterial contamination. The pool water yielded high counts of Pseudomonas vesicularis, Pseudomonas aeruginosa, and CDC Group IV C2, even in the presence of adequate levels of free chlorine. This was found to be due to high concentrations of cyanuric acid which resulted in a 'chlorine lock'. The source of the P. vesicularis and CDC Group IV C2 was found to be the pool hose and this problem was alleviated by flushing it with water each day before use. The source of the P. aeruginosa was the pool pumps, and was eradicated by regularly shock dosing them with 6-8 ppm of free chlorine.     

Neosartorya fischeri var fischeri (Wehmer) Malloch and Cain 1972 (Anamorph: Aspergillus fischerianus Samson and Gams 1985) as a cause of mycotic keratitis

The first case of mycotic keratitis caused by Neosartorya fischeri var. fischeri the telemorph of Aspergillus fischerianus, is described. The patient, a 62-year-old man, had no history of trauma to his infected left eye. The infection progressed despite treatment with ketoconazle and the eye had to be eviscerated.Histological studies revealed the presence of hyaline, septate mycelium in the eye tissue. Cultures gave rise to a thermotolerant mould that developed both its asexual and sexual forms. The isolate was identified on the basis of the morphologic features of its anamorphic and teleomorphic states.In the literature only seven other species of Aspergillus have been unequivocally reported as causing mycotic keratitis.     

Microscopic studies on the Aspergillus flavus infected kernels of commercial peanuts in Georgia

This article describes the use of microscopy to prove the presence of the aflatoxin producing pathogen, Aspergillus flavus Link ex Fries in commercially available edible peanuts in Georgia. Light microscopy in combination with electron microscopy has been used to describe the infection course established by the fungus. The alkali maceration technique used in the study was successful and sufficient to detect the kernel infection of A. flavus and monitor the infection percentage in edible peanuts. Percentage of infected kernel varied from one commercial outlet to another in the region. Briefly, peanut seeds from Cartersville had the highest percentage of A. flavus infection. Electron microscopy confirmed the seed-borne infection of this mold. Mycelium established inside the host tissues both intercellularly and intracellularly aided by active, continuous branching of young hyphae. Establishment of mycelium was also detected in the xylem vessels of roots indicative of systemic infection. Thus, edible peanuts can form an important source of inoculum and facilitate the spread of the fungus from one peanut to another in commercial outlets and elsewhere. Present study provides strong evidence that A. flavus can escape detection at selling points and lands in commercial outlets via edible peanuts. That these contaminated peanuts could pose public health hazards is discussed.     

侵袭性非伤寒沙门菌血清型和耐药性分析

目的分析7株侵袭性非伤寒沙门菌(iNTS)的血清型和耐药性。方法针对收集的7株iNTS菌株,开展血清学鉴定、药物敏感性实验以及全基因组测序,并对血清型、MLST型和耐药基因进行鉴定、注释和分析。结果7株iNTS菌株中,包含1株鼠伤寒血清型和2株Ⅰ4,[5],12:i:-(ST34型)、2株肠炎血清型、1株科瓦利斯血清型和1株未知血清型Ⅰ4,[5],12:d:-(ST279型),其中6株为单相菌,沙门菌二相鞭毛基因缺失或假基因化可能有助于增强沙门菌侵袭性。未发现替加环素、氨曲南、阿米卡星及头孢类、碳青霉烯类抗生素耐药株,存在1株八重耐药鼠伤寒沙门菌。耐药基因与耐药表型基本相符。结论本研究中的iNTS菌株存在八重耐药株,整体耐药水平尚低但不可忽视。     

Identification and Chemical Enhancement of Two Ornamental Plants for Phytoremediation

With an increase in the contamination of urban areas, more and more attention has been paid to the role of ornamental plants in remedying contaminated soils. Thus, cadmium (Cd) tolerance and accumulation characteristics of Calendula officinalis and Althaea rosea as ornamental plants under the concentration gradient experiment with single Cd, as well as the effect of ethylenegluatarotriacetic acid (EGTA) and sodium dodecyl sulfate (SDS) on their Cd phytoremediation capacity under the chemically enhanced experiment was further investigated. It was showed that they had strong tolerance and accumulation capacity of Cd under single Cd treatments, thus they had great potential to be used for Cd contaminated soil remediation. Furthermore, under chemically enhanced treatments, the great efficiency was found through applying EGTA and SDS, they could not only increase the dry biomass of the plants, but also promote the Cd accumulation in shoots and roots. Particularly, Althaea rosea can be regarded as a potential Cd-hyperaccumulator through applying chemical agents. In conclusion, the two ornamental plants are promising to be used for phytoremediation.     

Molecular typing of Aspergillus terreus isolates by random amplification of polymorphic DNA

Forty three isolates of Aspergillus terreus of environmental or clinical origin were typed by random amplification of polymorphic DNA (RAPD) with two different primers NS3 and NS7 from the fungal ribosomal 18S subunit gene. For the 31 epidemiologically unrelated isolates tested, the primers NS3 and NS7 gave rise to 23 and 24 different genotypes, respectively, and combining the results obtained with the two primers allowed the differentiation of all these isolates. No clustering was found in relation to pathogenicity, clinical signs, or geographic origin of the isolates. Five groups of related isolates of A. terreus were also typed. Analysis of sequential isolates from patients with cystic fibrosis or with invasive aspergillosis showed the clonality of the colonization or infection by A. terreus. Likewise, this straightforward typing method demonstrated the clonal origin of a massive contamination of the environment in a haematology unit. Therefore this RAPD typing method may constitute a valuable tool for the epidemiological follow-up of airway colonization in patients with cystic fibrosis or investigations of links between nosocomial outbreaks of invasive aspergillosis and environmental contamination.