Reduced Detection Rates Research Articles

An Improved Design for a Cloud Intrusion Detection System Using Hybrid Features Selection Approach with ML Classifier

The rapid adoption of cloud computing has introduced new security concerns, particularly regarding data privacy and protection from sophisticated cyberattacks. Intrusion Detection Systems (IDSs) based on Machine Learning (ML) offer improved detection of malicious behaviour in network traffic. However, existing IDS solutions struggle with large-dimensional data and imbalanced datasets, resulting in higher false positive rates (FPR) and reduced detection rates (DR). In this paper, we propose an improved Cloud IDS leveraging a hybrid features selection approach using Information Gain (IG), Chi-square (CS), and Particle Swarm Optimization (PSO). To address the challenge of imbalanced datasets, the Synthetic Minority Over-sampling Technique (SMOTE) is employed. The Random Forest (RF) classifier is used to detect and classify attacks. The system is evaluated on the UNSW-NB15 and Kyoto datasets, achieving accuracies of over 98% and 99%, respectively, outperforming other methods in terms of detection accuracy.

Blood culture bottles meet the operating room: enhancing the diagnostic accuracy of infectious spondylitis through open microsurgical biopsy and intraoperative inoculation.

Infectious spondylitis is caused by hematogenous seeding or adjacent soft tissue infection. No study has provided evidence that incubating biopsy specimens in blood culture bottles could enhance detection rates, nor has any study compared this method with conventional culture techniques. We aimed to assess the diagnostic yield of open microsurgical biopsies for infectious spondylitis and the efficacy of various culture media in the presence and absence of pre-biopsy antibiotic therapy. This retrospective study, which was conducted at a university-affiliated teaching hospital in Korea, enrolled 165 adult patients with suspected infectious spondylitis between February 2014 and September 2020. The diagnostic yield of open biopsy was compared among three culture media, namely, blood culture bottles, swab culture using transport media, and tissue culture using plain tubes, while considering preoperative antibiotic exposure. Causative bacteria were identified in 84.2% of all cases. Blood culture bottles had the highest positivity rate (83.5%), followed by swab cultures (64.4%) and tissue cultures (44.9%). The differences in positivity rates were significant (P < 0.001). Preoperative antibiotic therapy reduced detection rates across all media, particularly in tissue cultures. We established the high diagnostic yield of open microsurgical biopsy using blood culture bottles, suggesting that pre-biopsy antibiotic therapy significantly affects bacterial detection, thereby underscoring the importance of culture medium selection in the diagnosis of infectious spondylitis.

Mycoplasma pneumoniae detections in children with lower respiratory infection before and during the COVID-19 pandemic: a large sample study in China from 2019 to 2022

BackgroundNonpharmaceutical interventions (NPIs) implemented to reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have suppressed the spread of other respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to explore the epidemiological trends and clinical characteristics of Mycoplasma pneumoniae (MP) infection among inpatient children with lower respiratory tract infection (LRTI) before and during the COVID-19 pandemic, and investigate the long-term effects of China’s NPIs against COVID-19 on the epidemiology of MP among inpatient children with LRTI.MethodsChildren hospitalised for LRTI at the Department of Pulmonology, The Children’s Hospital, Zhejiang University School of Medicine (Hangzhou, China) between January 2019 and December 2022 were tested for common respiratory pathogens, including Mycoplasma pneumoniae (MP), Chlamydia trachomatis (CT) and other bacteria. Clinical data on age, sex, season of onset, disease spectrum, and combined infection in children with MP-induced LRTI in the past 4 years were collected and analysed.ResultsOverall, 15909 patients were enrolled, and MP-positive cases were 1971 (34.0%), 73 (2.4%), 176 (5.8%), and 952 (20.6%) in 2019, 2020, 2021, and 2022, respectively, with a significant statistical difference in the MP-positive rate over the 4 years (p <0.001). The median age of these children was preschool age (3–6 years), except for 2022, when they were school age (7–12 years), with statistical differences. Comparing the positive rates of different age groups, the school-age children (7–12 years) had the highest positive rate, followed by the preschoolers (3–6 years) in each of the 4 years. Compared among different seasons, the positive rate of MP in children with LRTI was higher in summer and autumn, whereas in 2020, it was highest in spring. The monthly positive rate peaked in July 2019, remained low from 2020 to 2021, and rebounded until 2022. Regarding the disease spectrum, severe pneumonia accounted for the highest proportion (46.3%) pre-pandemic and lowest (0%) in 2020.ConclusionTrends in MP detection in children with LRTIs suggest a possible correlation between COVID-19 NPIs and significantly reduced detection rates. The positivity rate of MP gradually rose after 2 years. The epidemic season showed some differences, but school-age children were more susceptible to MP before and during the COVID-19 pandemic.

Response of harbor porpoises (Phocoena phocoena) to different types of acoustic harassment devices and subsequent piling during the construction of offshore wind farms

Before piling of offshore wind farm foundations, acoustic harassment devices (AHDs) are used to drive harbor porpoises out of the area where they could suffer injuries. Until 2017, a combination of pingers and seal scarer devices (usually SPL = 174-193 dB re 1 μPa (rms) @ 1m at 1 to 20 kHz depending on the device) was prescribed for mitigation purposes in Germany. However, seal scarers led to decreased porpoise detection rates in much larger distances than intended, when 750 m is usually rendered sufficient to avoid injuries. Therefore, devices specifically designed for mitigation purposes were developed and are prescribed since then. These acoustic porpoise deterrents (APDs; e.g. FaunaGuard Porpoise Module; SPL = 172 dB re 1 μPa (rms) @ 1m at 60 to 150 kHz) aim to keep the animals away from offshore construction sites but should not lead to large-scale disturbance as caused by a seal scarer. Although project-specific evaluations indicated that APDs are effective, a cross-project analysis and a comparison with data from previous piling procedures employing seal scarers were still pending. The present study aimed to fill this gap. Between March 2018 and April 2019, harbor porpoise detection rates were monitored acoustically in four offshore wind farm projects using CPODs before, during and after piling at different distances up to 10 km from piling. APD operation led to a significant decrease in detection rates in the vicinity of the device, indicating the displacement of the animals from a small-scale area. Depending on the wind farm, detection rates during APD operation decreased by 30 to 100% at 750 m distance compared to 6 hours before APD operation. Furthermore, reduced detection rates during APD operation were only observed up to about 2.5 km distance even when the APD was switched on for over 40 minutes. Given that the extent of disturbance to harbor porpoises is lower when using an acoustic porpoise deterrent compared to the seal scarer, we consider that preferential use of an acoustic porpoise deterrent is an improvement to mitigation strategies and an important step forward to a less harmful piling procedure.

Advanced EGAN-IDS Framework for Resilience against Adversarial Attacks using Multi-headed Attention Module

A network's security depends heavily on its network intrusion detection system (NIDS). Monitoring network traffic continuously and spotting any unusual activity is its main duty. Even though several methods, such as machine learning-based network intrusion detection systems (ML-NIDSs), have been put forth and put into practice to improve the detection of malicious network traffic, many of the studies that have already been done do not adequately replicate real-world situations, where new attack types are continually emerging. Thus, more research is needed to determine how resistant intrusion detection systems are too adversarial and zero-day attacks. We provide and expand the Enhanced Generative Adversarial Network (EGAN-IDS) framework in this study. This framework creates hostile attack routes that are intended to avoid being discovered by five distinct Black Box ML-based intrusion detection systems. Artificial neural networks and self-awareness processes are used by EGAN-IDS to generate artificial adversarial attacks that are able to evade detection. According to our evaluation results, EGAN-IDS has produced adversarial patterns for a variety of attacks, which has reduced detection rates by an average of 15.93% for each of the five IDSs. These conclusions highlight the model's resilience and broad applicability.

Atypically slow processing of faces and non-faces in older autistic adults.

Face recognition is a fundamental function that requires holistic processing. Differences in face processing have been consistently identified in autistic children, but it is unknown whether these differences persist across the adult lifespan. Using event-related functional magnetic resonance imaging, we measured holistic face processing with a rapid Mooney faces task in 50 autistic and 49 non-autistic participants (30–74 years). Behavioral tasks included a self-paced version of the same paradigm and a global–local processing task (Navon). Reduced detection rates for faces, but not non-faces, were found in autistic adults, including slower responses on all conditions. Without time constraints, differences in accuracy disappeared between groups, although reaction times in correctly identifying faces remained higher in autistic adults. The functional magnetic resonance imaging results showed lower activation in the left and right superior frontal gyrus in the autism group but no age-related differences. Overall, our findings point toward slower information processing speed rather than a face recognition deficit in autistic adults. This suggests that face-processing differences are not a core feature of autism across the adult lifespan.Lay abstractSome theories suggested that social difficulties in autism arise from differences in the processing of faces. If face-processing difficulties are central to autism, then they should be as persistent as social difficulties across the lifespan. We tested this by asking autistic and neurotypical participants between 30 and 75 years to complete face detection tasks. Both autistic and neurotypical adults responded more slowly with age. When participants had to respond quickly, autistic adults made more errors in face detection regardless of their age. However, when the time constraint was removed, autistic adults performed as well as the neurotypical group. Across tasks, autistic adults responded more slowly when asked to detect both face and non-face stimuli. We also investigated brain activation differences in the face detection task with functional magnetic resonance imaging. The results indicated lower activation in the autism group in the left and right superior frontal gyrus. The superior frontal gyrus is not typically implicated in face processing but in more general processing, for example, keeping instructions in mind and following them. Together with the behavioral results, this suggests that there is no specific deficit in face processing in autistic adults between 30 and 75 years. Instead, the results suggest differences in general processing, particularly in the speed of processing. However, this needs to be investigated further with methods that are more sensitive to the timing of brain activation.

Fewer bat passes are detected during small, commercial drone flights

Advances in technological capabilities, operational simplicity and cost efficiency have promoted the rapid integration of unmanned aerial vehicles (UAVs) into ecological research, providing access to study taxa that are otherwise difficult to survey, such as bats. Many bat species are currently at risk, but accurately surveying populations is challenging for species that do not roost in large aggregations. Acoustic recorders attached to UAVs provide an opportunity to survey bats in challenging habitats. However, UAVs may alter bat behaviour, leading to avoidance of the UAV, reduced detection rates and inaccurate surveys. We evaluated the number of bat passes detected with and without the presence of a small, commercial UAV in open habitats. Only 22% of bat passes were recorded in the presence of the UAV (0.23 ± 0.09 passes/min) compared to control periods without the UAV (1.03 ± 0.17 passes/min), but the effect was smaller on the big brown bat/silver-haired bat (Eptesicus fuscus/Lasionycteris noctivagans) acoustic complex. Noise interference from the UAV also reduced on-board bat detection rates. We conclude that acoustic records attached to UAVs may inaccurately survey bat populations due to low and variable detection rates by such recorders.

Impact of changes to national UK Guidance on testing for gestational diabetes screening during a pandemic: a single-centre observational study.

To examine the differences in detection rate for gestational diabetes (GDM) comparing the methodology recommended by the National Institute for Health and Clinical Excellence (NICE) compared with testing described as appropriate during the Covid-19 pandemic by the Royal College of Obstetricians and Gynaecologists (RCOG). Cohort study of women delivering between 1 January 2016 and 1 July 2020. London Teaching Hospital. All women delivering between 1 January 2016 and 13 May 2020 and follow up of women screening negative between 1 April 2020 and 13 May 2020. Retrospective study of prospectively collected data. Detection rate of gestational diabetes. Using the RCOG guidance, the overall rate of women identified as having gestational diabetes fell from 7.7% (1853/24168) to 4.2% (35/831)(P=0.0003). Of 230 women who tested negative according to the RCOG criteria from 1 April to 13 May but who subsequently had an oral glucose tolerance test, 47 (20.4%) were diagnosed as having gestational diabetes according to the NICE criteria. In our setting, the RCOG Covid-19 gestational diabetes screening regime failed to detect 47 of 82 (57%) women subsequently identified as gestational diabetics, and therefore cannot be recommended for general use. Screening for GDM using RCOG Covid criteria reduced detection rates.

Transcranial ultrasound stimulation in humans is associated with an auditory confound that can be effectively masked

BackgroundTranscranial ultrasound stimulation (TUS) is emerging as a potentially powerful, non-invasive technique for focal brain stimulation. Recent animal work suggests, however, that TUS effects may be confounded by indirect stimulation of early auditory pathways. ObjectiveWe aimed to investigate in human participants whether TUS elicits audible sounds and if these can be masked by an audio signal. MethodsIn 18 healthy participants, T1-weighted magnetic resonance brain imaging was acquired for 3D ultrasound simulations to determine optimal transducer placements and source amplitudes. Thermal simulations ensured that temperature rises were <0.5 °C at the target and <3 °C in the skull. To test for non-specific auditory activation, TUS (500 kHz, 300 ms burst, modulated at 1 kHz with 50% duty cycle) was applied to primary visual cortex and participants were asked to distinguish stimulation from non-stimulation trials. EEG was recorded throughout the task. Furthermore, ex-vivo skull experiments tested for the presence of skull vibrations during TUS. ResultsWe found that participants can hear sound during TUS and can distinguish between stimulation and non-stimulation trials. This was corroborated by EEG recordings indicating auditory activation associated with TUS. Delivering an audio waveform to participants through earphones while TUS was applied reduced detection rates to chance level and abolished the TUS-induced auditory EEG signal. Ex vivo skull experiments demonstrated that sound is conducted through the skull at the pulse repetition frequency of the ultrasound. ConclusionFuture studies using TUS in humans need to take this auditory confound into account and mask stimulation appropriately.

Application and optimization of reference change values for Delta Checks in clinical laboratory.

BackgroundDelta check is a patient‐based QC tool for detecting errors by comparing current and previous test results of patient. Reference change value (RCV) is adopted in guidelines as method for delta check, but the performance is not verified. We applied RCV‐based delta check method to patients' data and modified for application.Materials and methodsReference change value were calculated using results of internal QC materials and biological variation data. Test results of 17 analytes in inpatients, outpatients, and health examination recipients were collected. The detection rates of currently used delta check method and those of RCV‐based method were compared, and the methods were modified.ResultsReference change value‐based method had higher detection rates compared to conventional method. Applied modifications reduced detection rates. Removing the pairs of results within reference interval reduced detection rates (0.42% ~ 10.92%). When RCV was divided by time interval, the detection rates were similar to prior rates in outpatients (0.19% ~ 1.34%). Using RCV multiplied by twice the upper limit of reference value as cutoff reduced the detection rate (0.07% ~ 1.58%).ConclusionsReference change value is a robust criterion for delta check and included in clinical laboratory practice guideline. However, RCV‐based method generates high detection rates which increase workload. It needs modification for use in clinical laboratories.

UAS imagery reveals new survey opportunities for counting hippos.

IntroductionThe common hippopotamus Hippopotamus amphibius L. is a vulnerable species that requires efficient methods to monitor its populations for conservation purposes. Rapid evolution of civil drones provides new opportunities but survey protocols still need development. This study aims to determine the optimal flight parameters for accurate population estimates. A second objective is to evaluate the effects of three environmental factors: wind speed, sun reflection and cloud cover.MethodWe estimated the population of two main hippo schools (Dungu and Wilibadi II) located in Garamba National Park in Democratic republic of Congo. Eight observers reviewed 252 photos taken over the Dungu school, representing a total of 2016 experimental units. A detection rate and a level of certainty were associated with each experimental unit, and five parameters were related to each count: flight height, three environmental parameters (sun reflection on water surface, cloud cover, and wind speed), and observers’ experience.ResultsFlight height reduced the observers’ confidence in their detection ability, rather than the detection itself. For accurate counts of large groups an average height of 150 m was shown to be a good compromise between animal detection without zooming in and the area covered in one frame. Wind speed had little influence on the counts, but it affected the performance of the UAS. Sun reflection reduced the detection rate of hippos and increased level of certainty, while cloud cover reduced detection rates slightly. Therefore, we recommend flying when the sun is still low on the horizon and when there is little cloud, or when cloud cover is light and even. This last point reinforces our recommendation for flights early in the day. The counts also showed large differences between groups of inexperienced and experienced observers. Experienced observers achieved better detection rates and were generally more confident in their detection. Experienced observers detected 86.5% of the hippos on average (confidence interval = ±0.76%). When applied to data from the second site, the detection was 84.3% (confidence interval = ±1.84%). Two correction factors were then calculated, as the inverse of the detection rate, based on the estimated number of hippos present during one flight (Factor 1) or in the general population respectively (Factor 2). Factor 2 especially was consistent with previous studies using traditional aerial counts (1.22 vs 1.25). Factor 2 was found to be appropriate for use by experienced observers. These results confirm the use of correction factor 2 for hippo surveys, regardless of the study site, as it accounts for hippo behavior. Optimum counting and cost efficiency were achieved with two trained observers counting 7 pictures.ConclusionThis study is a promising approach for routine surveys of the hippopotamus which is a species usually ignored in wildlife counts. Drone technology is expected to improve rapidly; therefore UAS could become a very useful and affordable survey tool for other species requiring specific monitoring.

Susceptibility of A. fumigatus-specific T-cell assays to pre-analytic blood storage and PBMC cryopreservation greatly depends on readout platform and analytes.

Mould-specific T cells detectable by flow cytometry or ELISPOT were proposed as a novel biomarker in invasive aspergillosis. To define protocols facilitating sample shipment and longitudinal analysis, this study evaluated the susceptibility of different functional assays for A. fumigatus-specific T-cell quantification and characterisation to pre-analytic delays. PBMCs from 6 healthy donors were analysed after immediate isolation, after 6hours whole blood storage or after cryopreservation using 3 different common media. Functional responses to A. fumigatus lysate stimulation were comparatively assessed by flow cytometry, ELISPOT and 14-plex cytokine assay. After 6hours pre-analytic storage, all functional assays showed reduced detection rates, higher coefficients of variation (CV) and widely varying individual recovery indices of specific T-cell response. While cryopreservation resulted in sufficient yields and largely unaltered cellular composition, outcomes of functional readouts significantly differed from freshly processed samples. For CD154-based flow cytometry, only cryopreservation in RPMI supplemented with autologous serum resulted in satisfactory detection rates and CVs. For ELISPOT and cytokine secretion assays, none of the cryopreservation protocols provided sufficient concordance with immediately processed samples. Even using the same readout platform, individual analytes widely varied in their susceptibility to cryopreservation, highlighting that distinct optimisation is required depending on the downstream assay.

Current prevalence and prevention of work-related musculoskeletal disorders among physicians for internal medical examination in tertiary hospitals in a city of China

Objective: To investigate the current prevalence and prevention of work-related musculoskeletal disorders (WMSDs) among physicians for internal medical examination, and to provide a theoretical basis for the prevention and treatment of WMSDs in physicians for internal medical examination. Methods: In February 2017, 326 physicians for internal medical examination were randomly selected from 5 general tertiary hospitals and 2 specialized tertiary hospitals in a city of China. A questionnaire was designed according to the Nordic Musculoskeletal Questionnaire and the occupational features of doctors in China to investigate the prevalence of musculoskeletal pain over the past year, the cognitive attitude to WMSDs, the knowledge of WMSDs prevention, and ways to get the knowledge of WMSDs prevention. Results: In the tertiary hospitals of this city, the symptoms of WMSDs were mainly seen in the wrist (75.78%) , neck (67.19%) , and lower back (58.59%) among male physicians, and in the wrist (73.74%) , lower back (70.95%) , and upper back (60.89%) among female physicians. Compared with the female physicians, the male physicians had a significantly increased detection rate of symptoms of WMSDs in the neck (P<0.05) and significantly reduced detection rates of symptoms of WMSDs in the upper and lower back (P<0.05). There were significant differences between the detection rates of symptoms of WMSDs in the neck, wrist, and lower back within the past 12 months, 7 days, and >1 month (P<0.01). The rates of knowledge of the severity and prevention of WMSDs were significantly different between the physicians with different working years and professional titles (P<0.01) . Conclusion: Among the physicians for internal medical examination in the tertiary hospitals of this city, WMSDs are mostly seen in the wrist, neck, and waist, and the knowledge of WMSDs prevention varies with different working years and professional titles.

Transient Distraction and Attentional Control during a Sustained Selective Attention Task.

Distracting stimuli in the environment can pull our attention away from our goal-directed tasks. fMRI studies have implicated regions in right frontal cortex as being particularly important for processing distractors [e.g., de Fockert, J. W., & Theeuwes, J. Role of frontal cortex in attentional capture by singleton distractors. Brain and Cognition, 80, 367-373, 2012; Demeter, E., Hernandez-Garcia, L., Sarter, M., & Lustig, C. Challenges to attention: A continuous arterial spin labeling (ASL) study of the effects of distraction on sustained attention. Neuroimage, 54, 1518-1529, 2011]. Less is known, however, about the timing and sequence of how right frontal or other brain regions respond selectively to distractors and how distractors impinge upon the cascade of processes related to detecting and processing behaviorally relevant target stimuli. Here we used EEG and ERPs to investigate the neural consequences of a perceptually salient but task-irrelevant distractor on the detection of rare target stimuli embedded in a rapid, serial visual presentation (RSVP) stream. We found that distractors that occur during the presentation of a target interfere behaviorally with detection of those targets, reflected by reduced detection rates, and that these missed targets show a reduced amplitude of the long-latency, detection-related P3 component. We also found that distractors elicited a right-lateralized frontal negativity beginning at 100 msec, whose amplitude negatively correlated across participants with their distraction-related behavioral impairment. Finally, we also quantified the instantaneous amplitude of the steady-state visual evoked potentials elicited by the RSVP stream and found that the occurrence of a distractor resulted in a transient amplitude decrement of the steady-state visual evoked potential, presumably reflecting the pull of attention away from the RSVP stream when distracting stimuli occur in the environment.

Evaluation of different real time PCRs for the detection of Pneumocystis jirovecii DNA in formalin-fixed paraffin-embedded bronchoalveolar lavage samples

The presence of Pneumocystis jirovecii in fresh clinical materials can be detected by PCR with high sensitivity and is thus preferred over microscopic methods. However, fresh materials are not always available, and on formalin-fixed paraffin-embedded materials, PCR may result in reduced detection rates. In this study the diagnostic sensitivity of P. jirovecii real time PCR on DNA isolated from fresh bronchoalveolar lavage (BAL) samples versus that from matched FFPE derived DNA is analyzed. Our results indicate that when targeting a small DNA fragment P. jirovecii PCR can be performed on FFPE BAL samples with acceptable sensitivity (up to 83.3%). This is considerably higher than the 33.3% positives observed by classical staining of these samples.

Identification of nasal colonization with β-lactamase-producing Enterobacteriaceae in patients, health care workers and students in Madagascar.

This study assesses the nasal occurrence of β-lactamase-producing Enterobacteriaceae both in patients in a hospital department of infectious diseases at admission and in healthy Madagascan students and health care workers. Nasal swabs from 681 students, 824 health care workers, and 169 patients were obtained in Antananarivo, Madagascar, and transferred to Germany. Screening for β-lactamase (ESBL, ampC) producing Enterobacteriaceae was performed by cultural and molecular approaches, comprising Brilliance ESBL agar, E-testing, ABCD-testing, and commercial hyplex ESBL and SuperBug ID PCR. Regarding ESBL-positive strains and strains with resistance against at least three out of the four tested bactericidal antibiotic drugs, 0.3% (five out of 1541) of the students and health care workers group showed nasal colonization, whereas colonization was observed in 7.1% (12 out of 169) of the hospitalized patients at admission. No appreciably reduced detection rates after sample storage and intercontinental transport were observed. A considerable proportion of nasal colonization with cephalosporin-resistant Enterobacteriaceae was demonstrated in Madagascan hospital patients at admission, posing a risk of developing future endogenous infections. The nasal colonization of healthy individuals was negligible. Good storage and transport stability of Enterobacteriaceae will allow for future studies even in areas difficult to access.

Multiplex real-time PCR and culture methods for detection of Shiga toxin-producing Escherichia coli and Salmonella Thompson in strawberries, a lettuce mix and basil

An appropriate approach of high throughput multi-screening was verified for Shiga toxin-producing Escherichia coli (STEC) and Salmonella spp. in strawberries, lettuce and basil. Sample replicates were inoculated with STEC O157 or O26 and Salmonella Thompson (ca. 10–70, 100–700 and 1000–7000cfu/25g) and analysed after 1 and 5days of storage (strawberries and lettuce at 7°C and basil at 10°C). After 18–24h of enrichment at 37°C in buffered peptone water, detection was performed using the GeneDisc multiplex PCR (stx1, stx2, eae and iroB genes) and selective culture media for isolation of STEC (with immunomagnetic separation (IMS)) and Salmonella spp. in parallel. After 1day, the pathogenic strains were recovered from all samples for all inoculum levels, whereas reduced detection rates of STEC O157 and S. Thompson were observed after 5days of storage in case of strawberries, in particular for the lowest inoculums level, suggesting superior survival potential for STEC O26. Overall, this study indicates the ability of PCR based screening methods for reproducible multi-detection of low numbers (10–70cfu/25g) of STEC and Salmonella in this type of foods. However, for the basil samples, PCR needed twofold dilution of the DNA extract to overcome inhibition. It was noted that on several occasions growth of competitive microbiota obstructed finding presumptive colonies on the selective agar media, whereas the use of an additional agar medium such as CHROMagar STEC (without IMS) improved recovery rate of STEC.

Estimation of citrus canker lesion size using hyperspectral reflectance imaging.

The Citrus industry has need for effective approaches to remove fruit with canker before they are shipped to selective international market such as the European Union. This research aims to determine the detectable size limit for cankerous lesions using hyperspectral imaging approaches. Previously developed multispectral algorithms using visible to near-infrared wavelengths, were used to segregate cankerous citrus fruits from other peel conditions (normal, greasy spot, insect damage, melanose, scab and wind scar). However, this previous work did not consider lesion size. A two-band ratio method with a simple threshold based classifier (ratio of reflectance at wavelengths 834 nm and 729 nm), which gave maximum overall classification accuracy of 95.7%, was selected for lesion size estimation in this study. The smallest size of cankerous lesion detected in terms of equivalent diameter was 1.66 mm. The effect of variation of threshold values and number of erosion cycles (applying morphological erosion multiple times to the image) on estimation of smallest detectable lesion was observed. It was found that small threshold values gave better canker classification accuracies, while exhibiting a lower overall classification accuracy. Meanwhile, higher threshold values portrayed the opposite tendency. The threshold value of 1.275 gave the optimum tradeoff between canker classification accuracy, overall classification accuracy and minimal lesion size detection. Increasing the number of erosion cycles reduced detection rates of smaller canker lesions, leading to the conclusion that a single erosion cycle gave the best size estimation results. The erosion kernel of the size 3 mm

Detecting pygmy rabbits (Brachylagus idahoensis) using DNA extracted from fecal pellets of mixed-species groups

Noninvasive genetic sampling is an essential tool for studying elusive and endangered species. However, the DNA from noninvasive genetic sampling tends to be low in quantity and quality, which leads to poor DNA amplification. Using fecal pellets of pygmy rabbits (Brachylagus idahoensis) collected in February, March, and November 2011, we tested a possible solution of increasing the amount of sample by combining multiple pellet groups during DNA extraction. One potential drawback of this approach is accidental mixing of samples from multiple species. This study evaluates the mitochondrial DNA (mtDNA) species identification success rate for pygmy rabbit (PY) fecal DNA when mixed with eastern cottontail (Sylvilagus floridanus; EC) fecal pellet DNA at lower frequencies (1PY:3EC and 2PY:6EC) and eastern cottontail or mountain cottontail (S. nuttalli) pellet samples at an equal frequency (4:4). We found that successful detection of pygmy rabbit DNA using a species-specific mtDNA polymerase chain reaction (PCR) test varies from 0% to 95% depending on the competing species and PCR protocol. From these results, we conclude that if samples are unintentionally mixed, the species with a greater number of pellets within the sample will be more likely to be detected. Also, if pellet piles are intentionally mixed to reduce sampling cost, the protocol should be optimized to maximize DNA amplification for the focal species; however, there will be reduced detection rates depending on the quality and quantity of the focal species DNA within the sample. © 2013 The Wildlife Society.

359 HLA FOOTPRINTS IN HIV/HCV CO-INFECTED PATIENTS

Background and Aims: HLA-diversity is a major host genetic risk factor in infectious diseases. In particular, several studies have described associations between distinct HLA alleles and outcomes of HCV and HIV infection. The objective of this study was to analyse the distribution of HLA Class I alleles in HIV/HCV co-infected individuals in order to identify HLA-disease associations that reflect the impact of this dual infection. Methods: Clinical data from 1110 Caucasian patients (HCV: n =477, HIV: n =181, HIV and HCV: n =346, healthy controls: n = 106) were retrieved by retrospective chart review. HLA-A and B allele distribution were determined by molecular methods (SSO and SSP) with HLA-resolution reduced to the 2-digit level to enable uniform comparisons. Fisher’s exact test and Chi-square tests with Yates correction for multiple testing were applied for statistical analysis. Results: Patients with HCV mono-infection were significantly older than patients in each other group (p < 0.001). MSM was the predominant risk factor for HIV infection (52%), while most HIV/HCV and HCV-infected patients had been infected via blood exposure (83%). The frequency of HLA alleles HLA-A*30 (p =0.023), HLA-B*08 (p =0.003), HLA-B*39 (p =0.003), and HLAB*49 (p =0.032) did not differ between the patient groups but was significantly reduced in infected patients as compared to healthy controls irrespective from the underlying type of infection. In contrast, HLA-B*57, which is assumed to increase chances of spontaneous HCV resolution and delay HIV progression, was selectively increased in patients with HIV mono-infection (13%) as compared to each other group (healthy controls: 9%, HIV/HCV and HCV mono-infection: 6% each; p =0.022). Conclusion: Reduced detection rates in HIVor HCV-monoand HIV/HCV co-infected patients indicate that alleles HLA-A*30, HLAB*08, HLA-B*39, and HLA-B*49 carry a poor prognosis but do not reflect interactions between HIVand HCV-infections. Patients with blood-borne infections usually acquire HCV first and HIV later on. Thus, finding a high HLA-B57 carrier rate in HIV+ patients but in none of the other groups indicates a protective role of this allele for both HIV and HCV infection. Taken together long-term exposure of Caucasian patients to HIV and HCV infection seems to induce subtle footprints in their HLA class I repertoire.