Evaluation of Staffordshire, Stoke on Trent Allied Health Professionals preceptorship programmes: a mixed method UK study.

AIM: This study aimed to evaluate current preceptorship provision across AHP professions in the Staffordshire, Stoke on Trent (SSOT) region of England to improve consistency, share and optimise best practice. BACKGROUND: Preceptorship, defined as a period of structured transition from newly qualified to an independent practitioner, is thought to improve recruitment and retention of staff and ultimately improve patient care. During the COVID pandemic, SSOT recognised the potential for graduates to lack confidence having had reduced clinical exposure as pre-registration students, and so a likely increased need to support newly qualified staff, and to evaluate existing AHP preceptorship provision. METHODS: An explanatory sequential mixed methods design, utilising a cross sectional survey questionnaire and two subsequent focus groups, explored existing AHP preceptorship in SSOT in 2021. Following ethical approval respondents were recruited via professional networks who completed an online survey questionnaire. Two subsequent focus groups enabled an in-depth exploration of survey results. Descriptive statistics summarised survey data and thematic analysis was used to describe focus group findings. RESULTS: SSOT AHPs (n = 217; 26% preceptees; 47% preceptors) participated in the survey questionnaire and 17 AHPs in the focus groups. 57% of preceptees rated existing preceptorship programmes to be "somewhat, or not effective". Preceptors reported feeling unprepared for their role. Both preceptees and preceptors reported that, post pandemic, most existing programs required revisions to be fit for purpose. Ten pragmatic summary recommendations were made. CONCLUSIONS: Allied Health Professions Preceptorship in SSOT was found to be inconsistent, poorly understood and inadequate. Revisions to preceptorship programs across Staffordshire and Stoke on Trent NHS Trusts have been instigated to reflect changes in AHP practice since the COVID pandemic.

Ipsilateral microcalcifications after breast-conserving surgery: is it possible to differentiate benign from malignant calcifications?

AIM: To analyse stereotactic biopsies of microcalcifications in patients with previous ipsilateral breast-conserving surgery (BCS) to identify the positivity rate, assess for an association between the patient's primary cancer or mammographic appearances of the microcalcifications, and the risk of recurrence. MATERIALS AND METHODS: Relevant patients from 2018-2020 were identified via a retrospective review of the prospectively maintained radiological procedure database. Clinicopathological features of the patients' primary tumour and new calcifications were obtained from the hospital electronic patient record system and the national integrated medical imaging system. RESULTS: Thirty-one percent of recurrences post-ipsilateral BCS presented as isolated microcalcifications on mammography. Fifty-three percent of patients undergoing stereotactic biopsy of ipsilateral calcifications had recurrence. A positive margin status was associated with new or recurrent malignancy. There was no significant correlation between oestrogen-receptor status, sentinel lymph node status, adjuvant radiotherapy or chemotherapy and the risk of recurrence. Calcifications within the tumour bed were more likely to be benign while calcifications within the same quadrant but remote from the tumour bed were more likely malignant. All coarse calcifications were benign while 67% of fine linear/fine linear branching and 89% of fine pleomorphic calcifications were malignant. CONCLUSION: Increased time since diagnosis, positive margin status, fine pleomorphic and fine linear calcifications in the same quadrant as the tumour bed were associated with malignancy. Patients with coarse calcifications and calcifications within the tumour bed may avoid stereotactic biopsy and undergo short-interval surveillance.

Capturing the Influence of Jet Fluctuations on Particles in Plasma Spraying.

Instabilities and fluctuations of the plasma jet in a thermal spray process can have a significant influence on the particle in-flight temperatures and velocities, affecting the properties of resulting plasma-sprayed coatings. Presented in this paper is a novel method for capturing the effects particles are exposed to in the plasma spraying process. High-speed camera images of a plasma jet generated by a cascaded three-cathode plasma generator (TriplexPro-210) were recorded for varying operating conditions. The images are processed using the inverse Abel transform. This transformation accounts for the fact that the images represent a 2D projection of the 3D jet and generates more accurate intensity values that the sprayed particles would experience. These images are then combined with particle tracks resulting from CFD simulations of the plasma jet to match the particles path with the recorded plasma jet. This new method allows a precise description of the plasma intensity experienced by individual particles with a high temporal resolution. The results show a high sensitivity of the method, even detecting the influence on the particles of the plasma jet originating from the cascaded triple arc plasma generator, which is considered as rather stable.

Concordance rate in cattle and sheep between genotypes differing in Illumina GenCall quality score.

Proper quality control of data prior to downstream analyses is fundamental to ensure integrity of results; quality control of genomic data is no exception. While many metrics of quality control of genomic data exist, the objective of the present study was to quantify the genotype and allele concordance rate between called single nucleotide polymorphism (SNP) genotypes differing in GenCall (GC) score; the GC score is a confidence measure assigned to each Illumina genotype call. This objective was achieved using Illumina beadchip genotype data from 771 cattle (12 428 767 genotypes in total post-editing) and 80 sheep (1 557 360 SNPs genotypes in total post-editing) each genotyped in duplicate. The called genotype with the lowest associated GC score was compared to the genotype called for the same SNP in the same duplicated animal sample but with a GC score of >0.90 (assumed to represent the true genotype). The mean genotype concordance rate for a GC score of <0.300, 0.300-0.549, and ≥0.550 in the cattle (sheep in parenthesis) was 0.9467 (0.9864), 0.9707 (0.9953), and 0.9994 (0.99997) respectively; the respective allele concordance rate was 0.9730 (0.9930), 0.9849 (0.9976), and 0.9997 (0.99998). Hence, concordance eroded as the GC score of the called genotype reduced, albeit the impact was not dramatic and was not very noticeable until a GC score of <0.55. Moreover, the impact was greater and more consistent in the cattle population than in the sheep population. Furthermore, an impact of GC score on genotype concordance rate existed even for the same SNP GenTrain value; the GenTrain value is a statistical score that depicts the shape of the genotype clusters and the relative distance between the called genotype clusters.

Etiology and perinatal outcome of periviable fetal growth restriction associated with structural or genetic anomaly.

OBJECTIVE: To investigate the etiology and perinatal outcome of periviable fetal growth restriction (FGR) associated with a structural defect or genetic anomaly. METHODS: This was a retrospective study of singleton pregnancies seen at a referral fetal medicine unit between 2005 and 2018, in which FGR (defined as fetal abdominal circumference ≤ 3rd percentile for gestational age) was diagnosed between 22 + 0 and 25 + 6 weeks of gestation. The study group included pregnancies with periviable FGR associated with a genetic or structural anomaly (anomalous FGR), while the control group consisted of structurally and genetically normal pregnancies with periviable FGR (non-anomalous FGR). Results of genetic testing, TORCH screen and postmortem examination, as well as perinatal outcome, were investigated. RESULTS: Of 255 pregnancies complicated by periviable FGR, 188 were eligible; of which 52 (28%) had anomalous FGR and 136 (72%) had non-anomalous FGR. A confirmed genetic abnormality accounted for 17/52 cases (33%) of anomalous FGR, with trisomy 18 constituting over 50% (9/17; 53%). The most common structural defects associated with FGR were central nervous system abnormalities (13/35; 37%). Overall, 12 (23%) cases of anomalous FGR survived the neonatal period. No differences were found in terms of perinatal survival between pregnancies with anomalous and those with non-anomalous FGR. CONCLUSIONS: Most pregnancies complicated by anomalous FGR were associated with a structural defect. The presence of an associated genetic defect was invariably lethal, while those with a structural defect, in the absence of a confirmed genetic abnormality, survived into infancy in over 90% of cases, with an overall one in three chance of perinatal survival. These data can be used for counseling prospective parents. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Heteropaternal superfecundation frequently occurs in multiple-bearing mob-mated sheep.

Heteropaternal superfecundation may be defined as the fertilisation of two or more ova during the same oestrus cycle as a result of more than one coital act from different males; this results in foetuses being born in the same litter of the same age but different paternity. Heteropaternal superfecundation is more likely to occur in poly-ovulatory species like sheep; moreover, female sheep are often mob-mated with several rams concurrently, thus providing an opportunity for a given female to be served by multiple males during the same oestrus cycle. The objective of the present study was to determine the frequency of heteropaternal superfecundation in six sheep flocks where most of the ewes, lambs and rams were genotyped. A total of 685 multiple-birth litters were available where the sire, dam and all lambs were genotyped. Of the 539 pairs of twins included in the analysis, 160 (i.e. 30%) were sired by two different rams. Of the 137 sets of triplets included in the analysis, 73 (i.e. 53%) were sired by more than one ram. Of the nine sets of quadruplets, eight were sired by two rams with the remaining litter being mono-paternal. The overall incidence of heteropaternal superfecundation among litters was therefore 35%. Given that the incidence of multiple births in these flocks was 65%, heteropaternal superfecundation is expected to be relatively common in sheep; this is especially true as all but two of the litter-mates were polyzygotic. Genotyping of progeny is one practical solution to identity such individuals.

The Role of Interventional Radiology in the Management of Obstetric and Gynaecological Haemorrhage

Aim We will review our experience of emergent arterial embolization used to treat haemodynamically unstable patients with obstetric and gynaecological haemorrhage. Methods This is a retrospective study of patients with haemodynamically unstable obstetric and gynaecological haemorrhage treated with emergent arterial embolization from 2010 to 2015. Results 22 patients (average age 41 (SD +/-9) years) had emergent arterial embolization. 63% had post-partum haemorrhage (PPH). 82% of cases were performed with conscious sedation and local anaesthesia. Embolization was technically successful in all cases. Embolization was clinically successful in 95% (21/22). In one case of PPH the patient represented six days later with recurrent bleeding and was treated with surgical suturing of the cervix. There were no complications or deaths. Conclusion Arterial embolization is a highly successful treatment of obstetric and gynaecological haemorrhage in unstable patients.

Assessing hepatitis C spontaneous clearance and understanding associated factors-A systematic review and meta-analysis.

New advances in the treatment of hepatitis C provide high levels of sustained viral response but their expense limits availability in publicly funded health systems. The aim of this review was to estimate the proportion of patients who will spontaneously clear HCV, to identify factors that are associated with clearance and to support better targeting of directly acting antivirals. We searched Ovid EMBASE, Ovid MEDLINE and PubMed from 1 January 1994 to 30 June 2015 for studies reporting hepatitis C spontaneous clearance and/or demographic, clinical and behavioural factors associated with clearance. We undertook meta-analyses to estimate the odds of clearance for each predictor. Forty-three studies met the inclusion criteria, representing 20 110 individuals, and 6 of these studies included sufficient data to estimate spontaneous clearance. The proportion achieving clearance within 3, 6, 12 and 24 months following infection were, respectively, 19.8% (95% CI: 2.6%-47.5%), 27.9% (95% CI: 17.2%-41.8%), 36.1% (95% CI: 23.5%-50.9%) and 37.1% (95% CI: 23.7%-52.8%). Individuals who had not spontaneously cleared by 12 months were unlikely to do so. The likelihood of spontaneous clearance was lower in males and individuals with HIV co-infection, the absence of HBV co-infection, asymptomatic infection, black or nonindigenous race, nongenotype 1 infection, older age and alcohol or drug problems. This study suggests that patients continue to spontaneously clear HCV for at least 12 months following initial infection. However, injecting drug users are comparatively less likely to achieve clearance; thus, they should be considered a priority for early treatment given the continuing risks that these individuals pose for onwards transmission.

Non-invasive brain stimulation for fine motor improvement after stroke: a meta-analysis.

The aim of this study was to determine whether non-invasive brain stimulation (NIBS) techniques improve fine motor performance in stroke. We searched PubMed, EMBASE, Web of Science, SciELO and OpenGrey for randomized clinical trials on NIBS for fine motor performance in stroke patients and healthy participants. We computed Hedges' g for active and sham groups, pooled data as random-effects models and performed sensitivity analysis on chronicity, montage, frequency of stimulation and risk of bias. Twenty-nine studies (351 patients and 152 healthy subjects) were reviewed. Effect sizes in stroke populations for transcranial direct current stimulation and repeated transcranial magnetic stimulation were 0.31 [95% confidence interval (CI), 0.08-0.55; P = 0.010; Tau2 , 0.09; I2 , 34%; Q, 18.23; P = 0.110] and 0.46 (95% CI, 0.00-0.92; P = 0.05; Tau2 , 0.38; I2 , 67%; Q, 30.45; P = 0.007). The effect size of non-dominant healthy hemisphere transcranial direct current stimulation on non-dominant hand function was 1.25 (95% CI, 0.09-2.41; P = 0.04; Tau2 , 1.26; I2 , 93%; Q, 40.27; P < 0.001). Our results show that NIBS is associated with gains in fine motor performance in chronic stroke patients and healthy subjects. This supports the effects of NIBS on motor learning and encourages investigation to optimize their effects in clinical and research settings.

Correction to: Advanced Robotic Therapy Integrated Centers (ARTIC): an international collaboration facilitating the application of rehabilitation technologies.

The original article [1] contains a small mistake concerning the ARTIC Team members mentioned in the Acknowledgements. The team member, Rocco Salvatore Calabrò had their name presented incorrectly. This has now been corrected in the original article.

Venous Thromboembolism - Risk Assessment Tool and Thromboprophylaxis Policy: A National Survey.

Venous Thromboembolic (VTE) events in hospitalised patients are associated with significant mortality and morbidity and a major economic burden on the health service. It is well established in the literature that active implementation of a mandatory risk assessment tool and thromboprophylaxis policy reduces the incidence of hospital associated thrombosis (HAT). This study examines the utilization of a VTE risk assessment tool and thromboprophylaxis (TP) policy in Irish hospitals that manage acute admissions. A national survey was distributed to forty acute hospitals throughout Ireland. The response rate was 78% (31/40). The results showed that only 26% (n=8/31) of acute hospitals in Ireland have a local implemented TP policy. Six (75%) of these eight had a risk assessment tool in conjunction with the TP policy. All respondents who did not report to have a TP policy and risk assessment tool agreed that they should implement VTE prevention policy at their hospital. Based on the data from this survey and evidence from the effectiveness of the VTE prevention programme introduced in the United Kingdom, there is a need for a national risk assessment and thromboprophylaxis policy in Ireland. This change in practice would have the potential to prevent or reduce the morbidity and mortality associated with hospital acquired thrombosis.

Incidence of Hospital Acquired Thrombosis (HAT) in a Tertiary Care Hospital.

Venous thromboembolism (VTE) is a major cause of preventable morbidity and mortality in hospitalized patients. In spite of guidelines, VTE prophylaxis continues to be underutilised, and hospital acquired thrombosis (HAT) continues to be a problem. This study was conducted to estimate the incidence of HAT in a tertiary referral centre and to examine whether VTE risk assessment and thromboprophylaxis (TP) were implemented. Patients 18 years and above, with a radiologically-confirmed acute VTE during the study period of 15 weeks were included. Acute VTE was diagnosed in 100 patients and HAT was diagnosed in 48. There were 12,024 admissions over the study period, therefore the incidence of HAT was 0.4%. TP was prescribed in only 35% of patients, and 65% did not receive any or appropriate TP. Hospitals without active implementation of a formal risk assessment tool and TP policy are likely to continue to have increased incidence of HAT.

Hospital Acquired Thrombosis (HAT) Prevention in an Acute Hospital; A Single Centre Cross-Sectional Study.

Evidence based guidelines are effective in reducing incidence of venous thromboembolism (VTE) which is associated with morbidly, mortality and economic burden. This study aimed to identify the proportion of inpatients who had a VTE risk assessment (RA) performed and who received thromboprophylaxis (TP), in Cork University Hospital. There was no structured RA tool at the time; information was obtained from medical and drug charts to ascertain if a RA was performed. Patients were then RA by researchers and stratified as per NICE guidelines and the proportion who received TP was calculated. One thousand and nineteen inpatients were screened. Risk was documented in 24% of cases. TP was prescribed in 43.2% of inpatients. Following application of a RA tool >80% were at high risk of VTE with low risk of bleeding with TP prescription in 46.3% of inpatients. A national collaborative effort should be encouraged to develop a standardized approach for safe RA of inpatients and prescription of TP for prevention of HAT.

Short-term outcome of periviable small-for-gestational-age babies: is our counseling up to date?

OBJECTIVE: There are limited data for counseling on and management of periviable small-for-gestational-age (SGA) fetuses. We therefore aimed to investigate the short-term outcome of periviable SGA fetuses in relation to the likely underlying cause. METHODS: This was a retrospective study of data from three London tertiary fetal medicine centers obtained between 2000 and 2015. We included viable singleton pregnancies with a severely small fetus, defined as those with an abdominal circumference ≤ 3rd percentile, identified between 22 + 0 and 25 + 6 weeks' gestation. Data obtained included fetal biometry, presence of placental anomalies, uterine and fetal Doppler and neonatal outcome. We excluded cases with structural abnormalities, proven or suspected abnormal karyotype or genetic syndromes. Cases were classified according to the suspected underlying cause of the small fetal size into one of the following categories: uteroplacental insufficiency, evidence of placental damage with normal uterine artery Doppler, viral infection, or unclassied. RESULTS: There were 245 cases included in the study. Of these, at diagnosis of SGA, 201 (82%) were categorized as uteroplacental cause, 13 (5%) as suspected placental cause, one (0.4%) as suspected viral cause and 30 (12%) could not be assigned to any of these categories. Overall, 101 (41%) cases survived the neonatal period; 89 (36%) underwent in-utero fetal demise, 22 (9%) died neonatally and 33 (14%) pregnancies were terminated. The diagnosis-to-delivery interval was 8.1 weeks in those that survived and 4.5 weeks in those that died neonatally. CONCLUSIONS: Almost 90% of periviable SGA cases are associated with uteroplacental insufficiency or intraplacental damage. Survival is related to gestational age at delivery, with outcomes better than might be assumed at diagnosis and some pregnancies reaching term. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The use of coancestry based on shared segments for maintaining genetic diversity.

We have evaluated the use of genomic coancestry coefficients based on shared segments for the maintenance of genetic diversity through optimal contributions methodology for populations of three different Austrian cattle breeds. This coancestry measure has been compared with the genomic coancestry coefficient calculated on a SNP-by-SNP basis and with pedigree-based coancestry. The regressions of the shared segments coancestry on the other two coefficients suggest that the former mainly reflect Identity By Descent but with the advantage over pedigree-based coancestry of providing the realized Identity By Descent rather than an expectation. The effective population size estimated from the rate of coancestry based on shared segments was very similar to those obtained with the other coefficients and of small magnitude (from 26.24 to 111.90). This result highlights the importance of implementing active management strategies to control the increase of inbreeding and the loss of genetic diversity in livestock breeds, even when the population size is reasonably large. One problem for the implementation of coancestry based on shared segments is the need of estimating the gametic phases of the SNPs which, given the techniques used to obtain the genotypes, are a priori unknown. This study shows, through computer simulations, that using estimates of gametic phases for computing coancestry based on shared segments does not lead to a significant loss in the diversity maintained. This has been shown to be true even when the size of the population is very small as it is usually the case in populations subjected to conservation programmes.

Dichorionic triplet pregnancies: risk of miscarriage and severe preterm delivery with fetal reduction versus expectant management. Outcomes of a cohort study and systematic review.

BACKGROUND: In trichorionic pregnancies, fetal reduction from three to two lowers the risk of severe preterm delivery, but provides no advantage in survival. Similar data for dichorionic triamniotic (DCTA) triplets is not readily available. OBJECTIVES: To document the natural history of DCTA triplets and the effect of reduction on the risk of miscarriage and severe preterm delivery, compared with expectant management. SEARCH STRATEGY: Systematic search on MEDLINE, EMBASE, and the Cochrane Library. SELECTION CRITERIA: DCTA triplets with three live fetuses at 8-14 weeks of gestation, outcome data with expectant management and/or reduction, miscarriage before 24 weeks of gestation and/or severe preterm delivery before 32-33 weeks of gestation. DATA COLLECTION AND ANALYSIS: Five studies were included. Data from these were combined with data from three centres. MAIN RESULTS: There were 331 DCTA triplets. The miscarriage rate was 8.9% (95% CI 5.8-13.3%) and the severe preterm delivery rate was 33.3% (95% CI 27.5-39.7%), with expectant management. The miscarriage rate was 14.5% (95% CI 7.6-26.2%) with a reduction of the monochorionic pair, 8.8% (95% CI 3.0-23.0%) with a reduction of one fetus of the monochorionic pair, and 23.5% (9.6-47.3%) with a reduction of the fetus with a separate placenta. Severe preterm delivery rates were 5.5% (95% CI 1.9-14-9%), 11.8% (95% CI 4.7-26.6%), and 17.6% (95% CI 6.2-41.0%), respectively. CONCLUSIONS: In DCTA triplets, expectant management is a reasonable choice when the top priority is a liveborn infant. Where the priority is to minimise severe preterm delivery, the most advisable option is fetal reduction. Further studies are needed to clarify which particular technique is advisable to optimise the outcome.

Strategies for single nucleotide polymorphism (SNP) genotyping to enhance genotype imputation in Gyr (Bos indicus) dairy cattle: Comparison of commercially available SNP chips.

Genotype imputation is widely used as a cost-effective strategy in genomic evaluation of cattle. Key determinants of imputation accuracies, such as linkage disequilibrium patterns, marker densities, and ascertainment bias, differ between Bos indicus and Bos taurus breeds. Consequently, there is a need to investigate effectiveness of genotype imputation in indicine breeds. Thus, the objective of the study was to investigate strategies and factors affecting the accuracy of genotype imputation in Gyr (Bos indicus) dairy cattle. Four imputation scenarios were studied using 471 sires and 1,644 dams genotyped on Illumina BovineHD (HD-777K; San Diego, CA) and BovineSNP50 (50K) chips, respectively. Scenarios were based on which reference high-density single nucleotide polymorphism (SNP) panel (HDP) should be adopted [HD-777K, 50K, and GeneSeek GGP-75Ki (Lincoln, NE)]. Depending on the scenario, validation animals had their genotypes masked for one of the lower-density panels: Illumina (3K, 7K, and 50K) and GeneSeek (SGGP-20Ki and GGP-75Ki). We randomly selected 171 sires as reference and 300 as validation for all the scenarios. Additionally, all sires were used as reference and the 1,644 dams were imputed for validation. Genotypes of 98 individuals with 4 and more offspring were completely masked and imputed. Imputation algorithms FImpute and Beagle v3.3 and v4 were used. Imputation accuracies were measured using the correlation and allelic correct rate. FImpute resulted in highest accuracies, whereas Beagle 3.3 gave the least-accurate imputations. Accuracies evaluated as correlation (allelic correct rate) ranged from 0.910 (0.942) to 0.961 (0.974) using 50K as HDP and with 3K (7K) as low-density panels. With GGP-75Ki as HDP, accuracies were moderate for 3K, 7K, and 50K, but high for SGGP-20Ki. The use of HD-777K as HDP resulted in accuracies of 0.888 (3K), 0.941 (7K), 0.980 (SGGP-20Ki), 0.982 (50K), and 0.993 (GGP-75Ki). Ungenotyped individuals were imputed with an average accuracy of 0.970. The average top 5 kinship coefficients between reference and imputed individuals was a strong predictor of imputation accuracy. FImpute was faster and used less memory than Beagle v4. Beagle v4 outperformed Beagle v3.3 in accuracy and speed of computation. A genotyping strategy that uses the HD-777K SNP chip as a reference panel and SGGP-20Ki as the lower-density SNP panel should be adopted as accuracy was high and similar to that of the 50K. However, the effect of using imputed HD-777K genotypes from the SGGP-20Ki on genomic evaluation is yet to be studied.

Oral intoxication of mice with Shiga toxin type 2a (Stx2a) and protection by anti-Stx2a monoclonal antibody 11E10.

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains cause food-borne outbreaks of hemorrhagic colitis and, less commonly, a serious kidney-damaging sequela called the hemolytic uremic syndrome (HUS). Stx, the primary virulence factor expressed by STEC, is an AB5 toxin with two antigenically distinct forms, Stx1a and Stx2a. Although both toxins have similar biological activities, Stx2a is more frequently produced by STEC strains that cause HUS than is Stx1a. Here we asked whether Stx1a and Stx2a act differently when delivered orally by gavage. We found that Stx2a had a 50% lethal dose (LD50) of 2.9 µg, but no morbidity occurred after oral intoxication with up to 157 µg of Stx1a. We also compared several biochemical and histological parameters in mice intoxicated orally versus intraperitoneally with Stx2a. We discovered that both intoxication routes caused similar increases in serum creatinine and blood urea nitrogen, indicative of kidney damage, as well as electrolyte imbalances and weight loss in the animals. Furthermore, kidney sections from Stx2a-intoxicated mice revealed multifocal, acute tubular necrosis (ATN). Of particular note, we detected Stx2a in kidney sections from orally intoxicated mice in the same region as the epithelial cell type in which ATN was detected. Lastly, we showed reduced renal damage, as determined by renal biomarkers and histopathology, and full protection of orally intoxicated mice with monoclonal antibody (MAb) 11E10 directed against the toxin A subunit; conversely, an irrelevant MAb had no therapeutic effect. Orally intoxicated mice could be rescued by MAb 11E10 6 h but not 24 h after Stx2a delivery.

Enhanced virulence of the Escherichia coli O157:H7 spinach-associated outbreak strain in two animal models is associated with higher levels of Stx2 production after induction with ciprofloxacin.

Shiga toxin (Stx)-producing Escherichia coli (STEC) causes hemorrhagic colitis and the hemolytic-uremic syndrome (HUS). STEC strains may produce Stx1a and/or Stx2a or variants of either toxin. A 2006 spinach-associated outbreak of STEC O157:H7 resulted in higher hospitalization and HUS rates than previous STEC outbreaks. The spinach isolate, strain K3995, contains both stx2a and stx2c. We hypothesized that the enhanced virulence of K3995 reflects the combination of stx2 alleles (carried on lysogenic phages) and/or the amount of Stx2 made by that strain. We compared the virulence of K3995 to those of other O157:H7 isolates and an isogenic Stx2 mutant in rabbits and mice. We also measured the relative levels of Stx2 produced from those strains with or without induction of the stx-carrying phage. Some rabbits infected with K3995 exhibited intestinal pathology and succumbed to infection, while none of those infected with O157:H7 strain 2812 (Stx1a(+) Stx2a(+)) died or showed pathological signs. Rabbits infected with the isogenic Stx2a mutant K3995 stx2a::cat were not colonized as well as those infected with K3995 and exhibited no signs of disease. In the streptomycin-treated mouse model, more animals infected with K3995 died than did those infected with O157:H7 strain 86-24 (Stx2a(+)). Additionally, K3995 produced higher levels of total Stx2 and toxin phage DNA in cultures after phage induction than did 86-24. Our results demonstrate the greater virulence of K3995 compared to other O157:H7 strains in rabbits and mice. We conclude that this enhanced virulence is linked to higher levels of Stx2 expression as a consequence of increased phage induction.