Impact of MALDI-TOF-MS-based identification directly from positive blood cultures on patient management: a controlled clinical trial

OBJECTIVES

Rapid identification of pathogens directly from positive blood cultures (BC) in combination with an antimicrobial stewardship programme (ASP) is associated with improved antibiotic treatment and outcomes, but the effect of each individual intervention is less clear. The current study investigated the impact of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) versus conventional identification on antibiotic management in a setting with a well-established ASP and low resistance rates.

METHODS

In this single-centre open label, controlled clinical trial 425 patients with positive BCs were allocated by weekday during a 1-year period to either MALDI-TOF directly from positive BCs or conventional processing. ASP was identical throughout the study period. The primary outcome was duration of intravenous antimicrobial therapy and was analysed in an intention-to-treat approach.

RESULTS

In all, 368 patients were analysed (MALDI-TOF n = 168; conventional n = 200) with similar baseline characteristics. Mean duration of intravenous antimicrobial therapy (12.9 versus 13.2 days, p 0.9) and length of stay (16.1 versus 17.9 days, p 0.3) were comparable. In the clinically significant bloodstream infection subgroup (n = 242) mean time from Gram-stain to active treatment was significantly shorter (3.7 versus 6.7 h, p 0.003). Admission to the intensive care unit after bloodstream infection onset was less frequent in the MALDI-TOF group (23.1 versus 37.2%, p 0.02).

CONCLUSIONS

Rapid identification of contaminated BCs (n = 126) resulted in a shorter duration of intravenous antimicrobial therapy (mean 4.8 versus 7.5 days, p 0.04). Rapid identification using MALDI-TOF directly from positive BCs did not impact on duration of intravenous antimicrobial therapy, but provided fast and reliable microbiological results and may improve treatment quality in the setting of an established ASP.

Legionnaires' disease on a cruise ship linked to the water supply system: clinical and public health implications

The occurrence of legionnaires' disease has been described previously in passengers of cruise ships, but determination of the source has been rare. A 67-year-old, male cigarette smoker with heart disease contracted legionnaires' disease during a cruise in September 1995 and died 9 days after disembarking. Legionella pneumophila serogroup 1 was isolated from the patient's sputum and the ship's water supply. Samples from the air-conditioning system were negative. L. pneumophila serogroup 1 isolates from the water supply matched the patient's isolate, by both monoclonal antibody subtyping and genomic fingerprinting. None of 116 crew members had significant antibody titers to L. pneumophila serogroup 1. One clinically suspected case of legionnaires' disease and one confirmed case were subsequently diagnosed among passengers cruising on the same ship in November 1995 and October 1996, respectively. This is the first documented evidence of the involvement of a water supply system in the transmission of legionella infection on ships. These cases were identified because of the presence of a unique international system of surveillance and collaboration between public health authorities.

A Multiplex PCR Assay for Detection of Pseudomonas syringae pv. actinidiae and Differentiation of Populations with Different Geographic Origin

Pseudomonas syringae pv. actinidiae is responsible for severe outbreaks of bacterial canker of kiwifruit currently occurring around the world. Although molecular detection methods have been reported, none provide complete selectivity for this pathovar or discriminate among pathogen haplotypes. Therefore, a new multiplex polymerase chain reaction (PCR) assay was developed and validated. The assay was tested on 32 P. syringae pv. actinidiae isolates and 15 non-P. syringae pv. actinidiae strains and correctly assigned P. syringae pv. actinidiae strains to three different haplotypes: a Japanese/Korean group, a European group, and a Chinese group. Two P. syringae pv. actinidiae isolates from New Zealand were found to belong to the Chinese group whereas two other isolates from New Zealand, which were isolated from kiwifruit plants but which do not cause bacterial canker, tested negative. The described PCR assays has a limit of detection of approximately 5 to 50 pg of purified DNA or of 5 × 10² bacteria/PCR and were shown to work with both artificially and naturally infected plant tissues. Thus, the described method represents a suitable tool for detection of P. syringae pv. actinidiae and haplotype attribution, in particular, when testing a high number of samples during surveillance and prevention activities.

Assessment of internal mammary artery and saphenous vein graft patency and flow reserve using transthoracic Doppler echocardiography

OBJECTIVE

To investigate transthoracic Doppler echocardiography in the identification of coronary artery bypass graft (CABG) flow for assessing graft patency.

DESIGN

The initial study group comprised 45 consecutive patients with previous CABG undergoing elective cardiac catheterisation for recurrent ischaemia. The Doppler variables best correlated with angiographic graft patency were then tested prospectively in a further 84 patients (test group).

SETTING

Three tertiary referral centres.

INTERVENTIONS

Flow velocities in grafts were recorded at rest and during hyperaemia induced by dipyridamole (0.56 mg/kg/4 min), under the guidance of transthoracic colour Doppler flow mapping. Findings on transthoracic Doppler were compared with angiography.

MAIN OUTCOME MEASURES

Feasibility of identifying open grafts by Doppler and diagnostic accuracy for Doppler detection of significant (>/= 70%) graft stenosis.

RESULTS

In the test group the identification rate for mammary artery grafts was 100%, for saphenous vein grafts to left anterior descending coronary artery 91%, for vein grafts to right coronary artery 96%, and for vein grafts to circumflex artery 90%. Coronary flow reserve (the ratio between peak diastolic velocity under hyperaemia and at baseline) of < 1.9 (95% confidence interval 1.83 to 2.08) had 100% sensitivity, 98% specificity, 87.5% positive predictive value, and 100% negative predictive value for mammary artery graft stenosis. Coronary flow reserve of < 1.6 (95% CI 1.51 to 1.73) had 91% sensitivity, 87% specificity, 85.4% positive predictive value, and 92.3% negative predictive value for significant vein graft stenosis.

CONCLUSIONS

Transthoracic Doppler can provide non-invasive assessment of CABG patency.

Asymmetry Index in Muscle Activations

Gait asymmetry is typically evaluated using spatio-temporal or joint kinematics parameters. Only a few studies addressed the problem of defining an asymmetry index directly based on muscle activity, extracting parameters from surface electromyography (sEMG) signals. Moreover, no studies used the extraction of the muscle principal activations (activations that are necessary for accomplishing a specific motor task) as the base to construct an asymmetry index, less affected by the variability of sEMG patterns. The aim of this paper is to define a robust index to quantitatively assess the asymmetry of muscle activations during locomotion, based on the extraction of the principal activations. SEMG signals were analyzed combining statistical gait analysis (SGA) and a clustering algorithm that allows for obtaining the muscle principal activations. We evaluated the asymmetry levels of four lower limb muscles in: (1) healthy subjects of different ages (children, adults, and elderly); (2) different populations of orthopedic patients (adults with megaprosthesis of the knee after bone tumor resection, elderly subjects after total knee arthroplasty, and elderly subjects after total hip arthroplasty); and (3) neurological patients (children with hemiplegic cerebral palsy and elderly subjects affected by idiopathic normal pressure hydrocephalus). The asymmetry index obtained for each pathological population was then compared to that of age-matched controls. We found asymmetry levels consistent with the expected impact of the different pathologies on muscle activation during gait. This suggests that the proposed index can be successfully used in clinics for an objective assessment of the muscle activation asymmetry during locomotion.

Chitosan Hydrochloride Decreases Fusarium graminearum Growth and Virulence and Boosts Growth, Development and Systemic Acquired Resistance in Two Durum Wheat Genotypes

Fusarium head blight (FHB) is a devastating disease for cereals. FHB is managed by fungicides at anthesis, but their efficacy is variable. Conventional fungicides accumulate in the soil and are dangerous for animal and human health. This study assayed the antifungal ability of chitosan hydrochloride against Fusarium graminearum. Chitosan reduced F. graminearum growth and downregulated the transcript of the major genes involved in the cell growth, respiration, virulence, and trichothecenes biosynthesis. Chitosan promoted the germination rate, the root and coleoptile development, and the nitrogen balance index in two durum wheat genotypes, Marco Aurelio (FHB-susceptible) and DBC480 (FHB-resistant). Chitosan reduced FHB severity when applied on spikes or on the flag leaves. FHB severity in DBC480 was of 6% at 21 dpi after chitosan treatments compared to F. graminearum inoculated control (20%). The elicitor-like property of chitosan was confirmed by the up-regulation of TaPAL, TaPR1 and TaPR2 (around 3-fold). Chitosan decreased the fungal spread and mycotoxins accumulation. This study demonstrated that the non-toxic chitosan is a powerful molecule with the potential to replace the conventional fungicides. The combination of a moderately resistant genotype (DBC480) with a sustainable compound (chitosan) will open new frontiers for the reduction of conventional compounds in agriculture.

The modulation of stomatal conductance and photosynthetic parameters is involved in Fusarium head blight resistance in wheat

Fusarium head blight (FHB) is one of the most devastating fungal diseases affecting grain crops and Fusarium graminearum is the most aggressive causal species. Several evidences shown that stomatal closure is involved in the first line of defence against plant pathogens. However, there is very little evidence to show that photosynthetic parameters change in inoculated plants. The aim of the present study was to study the role of stomatal regulation in wheat after F. graminearum inoculation and explore its possible involvement in FHB resistance. RT-qPCR revealed that genes involved in stomatal regulation are induced in the resistant Sumai3 cultivar but not in the susceptible Rebelde cultivar. Seven genes involved in the positive regulation of stomatal closure were up-regulated in Sumai3, but it is most likely, that two genes, TaBG and TaCYP450, involved in the negative regulation of stomatal closure, were strongly induced, suggesting that FHB response is linked to cross-talk between the genes promoting and inhibiting stomatal closure. Increasing temperature of spikes in the wheat genotypes and a decrease in photosynthetic efficiency in Rebelde but not in Sumai3, were observed, confirming the hypothesis that photosynthetic parameters are related to FHB resistance.

A Green Nanostructured Pesticide to Control Tomato Bacterial Speck Disease

Bacterial speck disease, caused by Pseudomonas syringae pv. tomato (Pst), is one of the most pervasive biological adversities in tomato cultivation, in both industrial and in table varieties. In this work synthesis, biochemical and antibacterial properties of a novel organic nanostructured pesticide composed of chitosan hydrochloride (CH) as active ingredient, cellulose nanocrystals (CNC) as nanocarriers and starch as excipient were evaluated. In order to study the possibility of delivering CH, the effects of two different types of starches, extracted from a high amylose bread wheat (high amylose starch-HA Starch) and from a control genotype (standard starch-St Starch), were investigated. Nanostructured microparticles (NMP) were obtained through the spray-drying technique, revealing a CH loading capacity proximal to 50%, with a CH release of 30% for CH-CNC-St Starch NMP and 50% for CH-CNC-HA Starch NMP after 24 h. Both NMP were able to inhibit bacterial growth in vitro when used at 1% w/v. Moreover, no negative effects on vegetative growth were recorded when NMP were foliar applied on tomato plants. Proposed nanostructured pesticides showed the capability of diminishing Pst epiphytical survival during time, decreasing disease incidence and severity (from 45% to 49%), with results comparable to one of the most used cupric salt (hydroxide), pointing out the potential use of CH-CNC-Starch NMP as a sustainable and innovative ally in Pst control strategies.

Hemodynamic evaluation of the Carbomedics R, St Jude Medical HP and Sorin-Bicarbon valve in patients with small aortic annulus

A Doppler echocardiographic study was performed to evaluate the hemodynamic performance of three 19 mm size currently used bileaflet valve prosthesis (St Jude Medical Hydrodinamic Plus, Sorin-Bicarbon and Carbomedic Reduced) implanted in aortic position.

METHODS

Patients, 30, with the same profile receiving 19 mm size valve (ten for each valve type) were selected when body surface area (BSA) was > 1.7 m2. Doppler echocardiography was carried out at rest and after exercise, 60 days after surgery. Peak (Pg) and mean (Mg) gradients across the valve were recorded: the effective orifice area (EOA), and performance index (PI) were calculated.

RESULTS

No significant differences were observed between St Jude Medical and Sorin Bicarbon as far as peak and mean gradient, effective orifice area and performance index at rest and after exercise. A significant difference (P < 0.05) was demonstrated in the above mentioned parameters when Carbomedics-R valve were tested. This type of valve showed a lower EOA and PI with higher Pg and Mg gradient both at rest and after exercise.

CONCLUSION

The St Jude Hydrodymanic plus (Hp) and Sorin Bicarbon valves had similar performance and a better hemodynamic trend when compared to the Carbomedics-R valve in patients with large body surface areas. The Carbomedics-R valve shows a ineffective use of the total area of the prosthesis both at rest and after exercise.

Role of methyl jasmonate and salicylic acid in kiwifruit plants further subjected to Psa infection: biochemical and genetic responses

The use of plant elicitors for controlling Pseudomonas syringae pv. actinidiae (Psa), the etiological agent of the kiwifruit bacterial canker (KBC), has been analysed in the past and, while salicylic acid (SA) seems to decrease disease susceptibility, methyl jasmonate (MJ) shows an opposite effect. However, the metabolic and genomic responses of Psa-infected plants following elicitation with these two compounds, as compared with non-elicited Psa-inoculated plants, are poorly understood, being the focus of this study. Micropropagated A. chinensis 'Hayward' plants were elicited with MJ or SA, and further inoculated with Psa. Fifteen days post-inoculation, Psa population in MJ-treated plants was increased by 7.4-fold, whereas SA elicitation led to decreased Psa colonization (0.5-fold), as compared with non-elicited inoculated plants. Additionally, elicitation with MJ or SA generally decreased polyphenols and lignin concentrations (by at least 20%) and increased total proteins (by at least 50%). MJ led to the upregulation of SOD, involved in plant antioxidant system, and reporter genes for the jasmonic acid (JA) (JIH and LOX1), abscisic acid (SnRK), SA (ICS1), and ethylene (ACAS1, ETR1 and SAM) pathways. Moreover, it increased ABA (40%) and decreased carotenoids (30%) concentrations. Contrastingly, comparing with non-elicited Psa-inoculated plants, SA application resulted in the downregulation of antioxidant system-related genes (SOD and APX) and of reporter genes for ethylene (ETR1) and JA (JIH and ETR1). This study contributes to the understanding of potential mechanisms involved in kiwifruit plant defences against Psa, highlighting the role of the JA, ABA and ethylene in plant susceptibility to the pathogen.

UAV-Based Thermal, RGB Imaging and Gene Expression Analysis Allowed Detection of Fusarium Head Blight and Gave New Insights Into the Physiological Responses to the Disease in Durum Wheat

Wheat is one of the world's most economically important cereal crop, grown on 220 million hectares. Fusarium head blight (FHB) disease is considered a major threat to durum (Triticum turgidum subsp. durum (Desfontaines) Husnache) and bread wheat (T. aestivum L.) cultivars and is mainly managed by the application of fungicides at anthesis. However, fungicides are applied when FHB symptoms are clearly visible and the spikes are almost entirely bleached (% of diseased spikelets > 80%), by when it is too late to control FHB disease. For this reason, farmers often react by performing repeated fungicide treatments that, however, due to the advanced state of the infection, cause a waste of money and pose significant risks to the environment and non-target organisms. In the present study, we used unmanned aerial vehicle (UAV)-based thermal infrared (TIR) and red-green-blue (RGB) imaging for FHB detection in T. turgidum (cv. Marco Aurelio) under natural field conditions. TIR and RGB data coupled with ground-based measurements such as spike's temperature, photosynthetic efficiency and molecular identification of FHB pathogens, detected FHB at anthesis half-way (Zadoks stage 65, ZS 65), when the percentage (%) of diseased spikelets ranged between 20% and 60%. Moreover, in greenhouse experiments the transcripts of the key genes involved in stomatal closure were mostly up-regulated in F. graminearum-inoculated plants, demonstrating that the physiological mechanism behind the spike's temperature increase and photosynthetic efficiency decrease could be attributed to the closure of the guard cells in response to F. graminearum. In addition, preliminary analysis revealed that there is differential regulation of genes between drought-stressed and F. graminearum-inoculated plants, suggesting that there might be a possibility to discriminate between water stress and FHB infection. This study shows the potential of UAV-based TIR and RGB imaging for field phenotyping of wheat and other cereal crop species in response to environmental stresses. This is anticipated to have enormous promise for the detection of FHB disease and tremendous implications for optimizing the application of fungicides, since global food crop demand is to be met with minimal environmental impacts.

Influence of pre-processing in the extraction of muscle synergies during human locomotion

The extraction of muscle synergies in human locomotion may be biased by the kind of pre-processing applied to electromyographic (EMG) data. The aim of this contribution is to analyze the differences in the muscle synergies extracted using a standard pre-processing procedure and a new procedure. The new procedure is based on the selection of the muscle's principal activations (necessary actuations of the muscle to accomplish its specific biomechanical task during gait), discarding secondary activations (with an auxiliary function in motor control). EMG signals were recorded from 12 muscles of a healthy volunteer who was asked to walk, at self-selected pace, for 5 minutes. A dataset of 193 gait cycles was collected and divided into 19 epochs of 10 concatenated gait cycles. The application of the new pre-processing procedure provided 5 instead of 6 muscle synergies accurately reconstructing the original EMG data matrix, and clearer and more stable neural activation commands. The new preprocessing procedure may be easily extended to the extraction of muscle synergies in other cyclic movements, such as running, stair climbing, cyclo-ergometer exercising, and swimming.

Outbreak of Bacterial Blossom Blight Caused by Pseudomonas viridiflava on Actinidia chinensis Kiwifruit Plants in Italy

During the springs from 2006 to 2008, a new disease was observed on 4- to 5-year-old Actinidia chinensis (cv. Jin Tao) trees in different commercial kiwifruit-production areas in northern Italy (Lombardy). Initially, disease occurrence was sporadic but later became widespread. Symptoms on flowers appeared as a dark brown rot of anthers, filaments, sepals, and whole buds. Blossoms abscised prematurely from buds. Symptoms appeared as confluent brown spots often present on rolled margins. Bacteria were isolated from symptomatic tissue on nutrient agar medium supplemented with 5% sucrose. The isolated bacteria were aerobic; produced a diffusible fluorescent pigment on King's B medium; levan, oxidase, and arginine dihydrydrolase negative, and catalase positive; rotted potato tuber tissue; caused a hypersensitive response on tobacco; and failed to reduce nitrate or utilize sucrose and were ice nuclease-positive at -5°C, suggesting the organism was P. viridiflava (1,3). Inoculation of 2-year-old A. chinensis cv. Jin Tao plants were carried out in the greenhouse under controlled environmental conditions (15 to 27°C, night/day; relative humidity up to 70%) by spraying five plants in bloom with a suspension (1 × 10⁸ CFU/ml) of isolated bacteria with a hand-held sprayer that produced large spray droplets. Symptoms, similar to those in nature, were observed on flowers and buds 3 to 5 days after inoculation and on leaves after 7 to 10 days. Using the same tests described above with the original strains, the strains that were isolated from symptomatic tissue were identified as Pseudomonas viridiflava. Seven bacterial strains (PV508-PV1108) were identified by sequencing 1,481 bp of their 16S rDNA region (2) and using BlastN (4) for the most similar sequences in the INSD (GenBank, EMBL, and DDBJ). Our sequences shared 99.53% (1,474 of 1,481 bp) to 99.9% (1480 of 1,481 bp) identity with the analogous sequences of P. viridiflava available in the database. To our knowledge, this is the first report of an outbreak of blossom blight caused by P. viridiflava on A. chinensis cv. Jin Tao kiwifruit plants in Italy. Previously, it was reported on A. deliciosa cv. Hayward (3). Because of the risk of bacterial contamination among the different cultivars of kiwifruit, further investigation and development of control measures are in progress. References: (1) R. A. Lelliott and D. E. Stead. Methods for the Diagnosis of Bacterial Diseases of Plants. Blackwell Scientific, Oxford, UK, 1987. (2) E. R. B. Moore et al. Syst. Appl. Microbiol. 19:478, 1996. (3) L. Varvaro et al. Inf. Fitopatol. 6:49, 1990. (4) Z. Zhang et al. J. Comput. Biol. 7(1-2):203, 2000.

On-line estimation of myoelectric signal spectral parameters and nonstationarities detection

In this communication, we present a method for detecting nonstationarities of random time series with an approximately Gaussian distribution of amplitudes. This method is suitable for real time implementation. Here we report some results obtained by applying them to a time series of spectral parameters of surface myoelectric signals, collected during voluntary isometric contractions of human muscles. Moreover, we describe the computerized system that we used to implement our detector of nonstationarity. This system is based on the TMS 320C25 DSP chip and realizes on-line estimation and display of spectral parameters, as well as detection of their nonstationarities, featuring a sampling frequency up to 20 k samples/s. A friendly user interface, fully menu driven, allows the user to select different options during the system's operation by means of hot keys. The accuracy of the system was tested by comparing its estimates with those of an off-line system, previously characterized, which we took as a reference. The estimates of spectral parameters obtained by means of the two systems were always consistent. The on-line stationarity detector was able to recognize rates of variation of the spectral parameters as small as 1%/s during contractions lasting 10-15 s. This sensitivity makes it suitable for clinical application. The set of results herein presented has been selected to highlight the main characteristics of the system.

First Report of Citrus Canker Caused by Xanthomonas citri in Somalia

Xanthomonas citri (synonym = Xanthomonas axonopodis pv. citri) (3) has been reported in several countries in Africa (1) but not Somalia. During 2006 and 2007, hyperplasia-type lesions, often surrounded by a water-soaked margin and yellow halo, typical of citrus canker caused by X. citri were found on 8- to 10-year-old lime (Citrus limetta) and grapefruit (Citrus × paradisi Macfed.) trees in northern and southern Somalia, respectively. Ten leaf samples diagnosed presumptively as citrus canker by Xac ImmunoStrip test kits (Agdia, Elkhart, IN) were mailed to the USDA Foreign Disease-Weed Science Research Unit at Ft. Detrick, MD. To confirm the identification of X. citri, isolations were made from several lesions from each sample onto yeast-dextrose-CaCO₃ (YDC) agar (2). Yellow, xanthomonad-like mucoid, convex colonies were purified and stored on YDC slants. Phenotypic tests were done as described (2), and real-time PCR assays were done using primers XCit8F and XCit5R with probe XCitP2 (N. W. Schaad, unpublished). For pathogenicity tests, cultures were grown overnight in liquid nutrient broth-yeast (4) medium adjusted to contain 1 × 10⁵ CFU/ml and inoculated into leaves of lime seedlings with the blunt end of a 2-ml syringe. After 21 to 30 days in a lighted dew chamber (Model I-60DLM; Percival Scientific, Inc. Perry, IA) at 30/23°C day/night, symptoms were recorded. Cultures of sample S-1 (northern Somalia) from lime were phenotypically atypical of X. citri, PCR negative, and nonpathogenic. However, cultures of samples 3 to 7 (southern Somalia) from grapefruit were typical of X. citri and PCR positive; cultures 3 and 4 were tested for pathogenicity and produced erumpent lesions on lime. Isolations onto YDC agar resulted in typical mucoid, convex, yellow, PCR-positive colonies. To our knowledge, this is the first report of X. citri on citrus plants in Somalia. Strains S3 and S4 have been deposited in ICPB at Ft. Detrick, MD as ICPB 11650 and 11651, respectively. References: (1) J. F. Bradbury. Guide to Plant Pathogenic Bacteria. CAB International, Egham, UK, 1986. (2) N. W. Schaad et al. Xanthomonas. Page 175 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al. eds. American Phytopathological Society, St. Paul. MN. 2001. (3) N. W. Schaad et al. Syst. Appl. Microbiol. 29:690, 2006. (4) A. K. Vidaver. Appl. Microbiol. 15:1523, 1967.

Bacterial load and protein deposits on 15-day versus 1-day disposable hydrophilic contact lenses

PURPOSE

This study quantified the bacterial load and protein deposits on 1- and 15-day disposable contact lenses after use in normal wearers.

METHODS

Sixteen patients were randomly assigned to a 1-day contact lens (1-Day Acuvue) in one eye and to a 15-day contact lens (Acuvue) in the contralateral eye. Only one specified solution was allowed for the care of 15-day lenses. All patients were evaluated every month for 6 months (at times T1, T2, T3, T4, T5, T6). At times T1, T3, and T5, the lenses were removed in a sterile fashion and sent for laboratory quantification of Staphylococcus aureus and Pseudomonas aeruginosa. At T2, T4, and T6, quantification of protein deposits was determined, and at T0 and T6, impression cytology of the conjunctiva was performed.

RESULTS

P. aeruginosa was not identified on any lens. At T1, T3, and T5, S. aureus was significantly greater on the 1-day versus 15-day lenses (p < 0.001). In contrast, protein deposits were significantly greater on the 15-day lenses at all time points (T2, T6: p < 0.01; T4: p < 0.05). Impression cytology of the 15-day lens eyes revealed a worsening trend compared to the 1-day lens; however, no statistically significant differences were found between the two groups (p = 0.29).

CONCLUSION

Results of this study suggest that the use of cleaning and preservative solutions can alter the ocular surface bacterial environment of the contact lens wearer and that these changes are not a direct consequence of contact lens wear. The bactericidal activity of these solutions could, with time, also affect ocular surface cells, leading to contact lens intolerance and ocular surface disease.

Severe Outbreak of Bacterial Canker Caused by Clavibacter michiganensis subsp. michiganensis on Tomato in Central Italy

From May to July 2010, severe outbreaks of bacterial canker of tomato (Solanum lycopersicum L.) were observed in 16 fields in the Province of Viterbo, central Italy. Cultivars affected were Uno Rosso, Peto 1296, UG 812, UG 822, and Podium. Disease incidence ranged from 70 to 100% and was highest for Uno Rosso followed by UG 812, UG 822, Peto 1296, and Podium. Leaf symptoms initially appeared as interveinal, pale green, water-soaked areas that quickly turned yellow-brown to necrotic, resembling sunburn. Infected parts of the plants began to wilt and then die. Light yellow-to-brown streaks or cankers appeared on stems and the cankers darkened. As the disease progressed, affected stems split lengthwise and a pale yellow-to-reddish brown discoloration of the vascular tissue was observed. The pith of infected stems turned brown, granular to mealy, and filled with cavities. Dividing the stem into two pieces lengthwise revealed yellowing of vascular tissues in the fruits that otherwise was asymptomatic. Eventually, vascular wilting and premature death of entire plants were observed. Once a month, infected samples were randomly collected three times from each field from five plants. A gram-positive, nonmotile, nonspore forming, aerobic, curved, rod-shaped bacterium was consistently isolated onto nutrient broth yeast extract agar medium from symptomatic plant tissues. Strains tested positive for gelatin liquefaction, H₂S production from peptone, utilization of citrate and negative for starch hydrolysis. Forty-five isolates were used to inoculate four-o'clock (Mirabilis jalapa L.) plants by injecting a bacterial suspension of the appropriate isolate in sterilized distilled water (10⁸ CFU/ml) into leaves (1). Known strains of Clavibacter michiganensis subsp. michiganensis (DPP22) and Pseudomonas fluorescens (DPP09N) were used as positive and negative control treatments, respectively. Four leaves per plant and three plants were inoculated for each bacterial strain and control treatment. All 45 tomato field isolates and the known strain of C. michiganensis subsp. michiganensis produced a hypersensitive reaction within 48 h. Pathogenicity tests were performed on 3-week-old, potted tomato seedlings (cv. Ciliegino) by placing a drop of the appropriate bacterial suspension (10⁸ CFU/ml) on wounds created by excising the leaf petiole. The inoculated plants were maintained at 26 ± 1°C in a greenhouse. The two control isolates were similarly inoculated onto tomato seedlings. After 15 days, all inoculated plants developed symptoms, whereas negative control plants remained asymptomatic. Bacteria reisolated from inoculated leaf lesions had the same characteristics as the original bacteria. A 1,400-bp region of the 16S rDNA was amplified from 15 of the 45 strains with primers NOC 1F (AGAGTTTGATCATGGCTCAG) and NOC 3R (ACGGTTACCTTGTTACGACTT) and sequenced (GenBank Accession Nos. HQ144228 to HQ144242; strains CmmVT1 to CmmVT15). A BlastN search of the sequences in GenBank revealed the tomato strains had 99 to 100% identity with the 16S rDNA sequences of C. michiganensis subsp. michiganensis strains (GenBank Accession Nos. EU 685335, AM711867, and AM410696). In Italy, this pathogen was first reported in 1914 in Vasto and later in a few other regions. However, to our knowledge, this is the first observation of widespread outbreaks in >300 ha of tomato fields with severe economic losses. Reference: (1) R. D. Gitaitis. Plant Dis. 74:58, 1990.

Boosting Immunity and Management against Wheat Fusarium Diseases by a Sustainable, Circular Nanostructured Delivery Platform

Fusarium head blight (FHB) and Fusarium crown rot (FCR) are managed by the application of imidazole fungicides, which will be strictly limited by 2030, as stated by the European Green Deal. Here, a novel and eco-sustainable nanostructured particle formulation (NPF) is presented by following the principles of the circular economy. Cellulose nanocrystals (CNC) and resistant starch were obtained from the bran of a high amylose (HA) bread wheat and employed as carrier and excipient, while chitosan and gallic acid were functionalized as antifungal and elicitor active principles. The NPF inhibited conidia germination and mycelium growth, and mechanically interacted with conidia. The NPF optimally reduced FHB and FCR symptoms in susceptible bread wheat genotypes while being biocompatible on plants. The expression level of 21 genes involved in the induction of innate immunity was investigated in Sumai3 (FHB resistant) Cadenza (susceptible) and Cadenza SBEIIa (a mutant characterized by high-amylose starch content) and most of them were up-regulated in Cadenza SBEIIa spikes treated with the NPF, indicating that this genotype may possess an interesting genomic background particularly responsive to elicitor-like molecules. Quantification of fungal biomass revealed that the NPF controlled FHB spread, while Cadenza SBEIIa was resistant to FCR fungal spread. The present research work highlights that the NPF is a powerful weapon for FHB sustainable management, while the genome of Cadenza SBEIIa should be investigated deeply as particularly responsive to elicitor-like molecules and resistant to FCR fungal spread.

Developing medical device software in compliance with regulations

In the last decade, the use of information technology (IT) in healthcare has taken a growing role. In fact, the adoption of an increasing number of computer tools has led to several benefits related to the process of patient care and allowed easier access to social and health care resources. At the same time this trend gave rise to new challenges related to the implementation of these new technologies. Software used in healthcare can be classified as medical devices depending on the way they are used and on their functional characteristics. If they are classified as medical devices they must satisfy specific regulations. The aim of this work is to present a software development framework that can allow the production of safe and high quality medical device software and to highlight the correspondence between each software development phase and the appropriate standard and/or regulation.

Thymol-Nanoparticles as Effective Biocides against the Quarantine Pathogen Xylella fastidiosa

Quarantine pathogens require the investigation of new tools for effective plant protection. In particular, research on sustainable agrochemicals is the actual challenge. Plant extracts, essential oils, and gels are natural sources of efficient biocides, such as aromatic secondary metabolites. Thymol is the major phenolic constituent of thyme and oregano essential oils, and it can inhibit many pathogenic microbes. Thymol nanoparticles were obtained through adsorption on CaCO₃ nanocrystals, exploiting their carrier action. High loading efficiency and capability were reached as verified through UV and TGA measurements. We report the first study of thymol effect on Xylella fastidiosa, conducing both fluorometric assay and in vitro inhibition assay. The first test confirmed the great antibacterial effect of this compound. Finally, an in vitro test revealed an interesting synergistic action of thymol and nanocarriers, suggesting the potential application of thymol-nanoparticles as effective biocides to control Xylella fastidiosa infection.

An open-label phase 1 dose-escalation clinical trial of a single intravenous administration of gemcitabine in dogs with advanced solid tumors

BACKGROUND

A broad range of gemcitabine dosages have been used in dogs.

HYPOTHESIS/OBJECTIVES

To determine maximally tolerated dose (MTD), dose-limiting toxicity (DLT), and preliminary antitumor activity of intravenous administration of gemcitabine in dogs with advanced solid tumors.

ANIMALS

Twenty-two client-owned dogs.

METHODS

Dogs with advanced cancer were prospectively enrolled in an open-label Phase 1 study of gemcitabine. Gemcitabine was administered as a 30-minute intravenous bolus starting at 800 mg/m(2), using escalation of 50 mg/m(2) increments with 3 dogs per dose level. MTD was established based on the number of dogs experiencing DLT assessed after 1 cycle. Treatment continued until disease progression or unacceptable toxicosis. Additional dogs were enrolled at MTD to better characterize tolerability, and to assess the extent and duration of gemcitabine excretion.

RESULTS

Twenty-two dogs were treated at 4 dose levels, ranging from 800 to 950 mg/m(2). Neutropenia was identified as DLT. MTD was 900 mg/m(2). DLT consisting of grade 4 febrile neutropenia was observed at 950 mg/m(2) in 2 dogs. There were no nonhematologic DLTs. Twenty dogs received multiple doses, and none had evidence of severe toxicosis from any of their subsequent treatments. At 900 mg/m(2), 2 complete and 5 partial responses were observed in dogs with measurable tumors. The amount of gemcitabine excreted in urine decreased over time, and was undetectable after the first 24 hours.

CONCLUSIONS AND CLINICAL IMPORTANCE

The recommended dose of gemcitabine for future Phase 2 studies is weekly 900 mg/m(2). In chemotherapy-naïve dogs with advanced solid tumor this dose level merits further evaluation.