Heavy metal pollution and co-selection for antibiotic resistance: A microbial palaeontology approach.

Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.

Assessing the performance of the Oxford Nanopore Technologies MinION.

The Oxford Nanopore Technologies (ONT) MinION is a new sequencing technology that potentially offers read lengths of tens of kilobases (kb) limited only by the length of DNA molecules presented to it. The device has a low capital cost, is by far the most portable DNA sequencer available, and can produce data in real-time. It has numerous prospective applications including improving genome sequence assemblies and resolution of repeat-rich regions. Before such a technology is widely adopted, it is important to assess its performance and limitations in respect of throughput and accuracy. In this study we assessed the performance of the MinION by re-sequencing three bacterial genomes, with very different nucleotide compositions ranging from 28.6% to 70.7%; the high G + C strain was underrepresented in the sequencing reads. We estimate the error rate of the MinION (after base calling) to be 38.2%. Mean and median read lengths were 2 kb and 1 kb respectively, while the longest single read was 98 kb. The whole length of a 5 kb rRNA operon was covered by a single read. As the first nanopore-based single molecule sequencer available to researchers, the MinION is an exciting prospect; however, the current error rate limits its ability to compete with existing sequencing technologies, though we do show that MinION sequence reads can enhance contiguity of de novo assembly when used in conjunction with Illumina MiSeq data.

Significance of the metastasis-inducing protein AGR2 for outcome in hormonally treated breast cancer patients.

The anterior gradient protein-2 (AGR2) is inducible by oestrogen and itself can induce metastasis in a rat model for breast cancer. Here, a rabbit antibody to recombinant human AGR2 was used to assess its prognostic significance in a retrospective cohort of 351 breast cancer patients treated by adjuvant hormonal therapy. The antibody stains 66% of breast carcinomas to varying degrees. The percentage of positive carcinoma cells in tumours directly correlates with the level of AGR2 mRNA (Spearman's rank correlation, P = 0.0007) and protein (linear regression analysis r2 = 0.95, P = 0.0002). There is a significant association of staining of carcinomas for AGR2 with oestrogen receptor alpha (ERalpha) staining and with low histological grade (both Fisher's Exact test P<0.0001). In the ERalpha-positive cases, but not the ERalpha-negative cases, when subdivided into the separate staining classes for AGR2, there is a significantly progressive decrease in patient survival with increased staining (log rank test, P = 0.006). The significant association of staining for AGR2 with patient death over a 10-year period (log rank test P = 0.007, hazard ratio = 3) only becomes significant at 6 years of follow-up. This may be due to the cessation of adjuvant hormonal therapy at an earlier time, resulting in adverse re-expression of the metastasis-inducing protein AGR2.

The ABC's of disaster response.

The readiness of our healthcare facilities to respond to terrorist acts or naturally occurring epidemics and disasters has been at the center of public attention since September 11, 2001. The many other tragic events that have occurred throughout the world since then further reinforce the need for all healthcare facilities and medical personnel to increase their level of preparedness if they wish to optimize outcomes. Maximizing survival rates and minimizing disability during any MCI hinges on rapid, seamless, and coordinated response between first responders and first receivers. The Incident Command System and the HEICS are organizational tools that form the foundation for such a rapid and coordinated response. The ICS provides a simple and adaptable management structure that is capable of being expanded or contracted to meet the needs of a specific situation. The HEICS adapts the ICS into the hospital setting and, in addition to the benefits stated above; its use of the ICS nomenclature and terminology facilitates the communication and the sharing of resources between all agencies and health care institutions involved. A basic knowledge and understanding of the ICS principles and structure is essential for all individuals participating in a disaster response. Previous efforts at disaster preparedness have focused predominantly on the pre-hospital and rescue phase of the disaster response, but a complete and coordinated community response requires creation of integrated disaster plans. True readiness can only be achieved by testing and modifying these plans through integrated simulation drills and table top exercises. Hospital-wide drills are essential to educate all staff members as to their institutional plan and serve as the only substitute at present to first hand experience. At present, there is no evidence-based literature to define what constitutes the best medical response by medical personnel within a disaster setting. This information will likely evolve over the next several decades as we now recognize Disaster Medicine as a separate scientific and medical entity. In the interim, we can develop and modify our response plans based on the "lessons learned" from past experience. Prior events have demonstrated that general surgeons and surgical subspecialists are critical components to a successful hospital response for the vast majority of all mass casualty incidents. Thus, surgeons must take responsibility for increasing their knowledge and understanding of basic disaster management principles and must play an active role in developing their institutional disaster plans.

Correlation of mRNA for oestrogen receptor beta splice variants ERbeta1, ERbeta2/ERbetacx and ERbeta5 with outcome in endocrine-treated breast cancer.

This study has been performed to test the hypothesis that different oestrogen receptor beta (ERbeta) splice variants may be important determinants of clinical parameters, including outcome, in post-menopausal women with breast cancer receiving adjuvant endocrine treatment but no chemotherapy. Splice variants ERbeta1, ERbeta2 and ERbeta5 have been analysed by semi-quantitative RT-PCR in a cohort of 105 patients with primary breast cancer. Clinical correlates included age, grade, size, nodal status, ERalpha, progesterone receptor, Ki67, relapse-free survival (RFS) and overall survival (OS). Seventy per cent of cases were ERbeta1 positive, 69% ERbeta2 positive and 70% ERbeta5 positive. Within the cohort, 47% were positive for all three variants while 10% were negative for all three. ERbeta1 exhibited no discernible relationship with disease outcome. ERbeta2 and ERbeta5 expression was significantly associated with better RFS (P<0.005), and ERbeta2 with better OS (P=0.0002). In multivariate analysis, ERbeta2 (P=0.006), nodal status and the level of Ki67 expression were independent predictors for RFS while ERbeta2 (P=0.0008) and Ki67 status were independent predictors for OS. In the ERalpha-positive cases, or in the subset of those receiving adjuvant tamoxifen, ERbeta2 was significantly associated with good RFS (P<0.0005) and was the only independent marker of OS. We conclude that precise identification of splice variants of ERbeta are more important assessors than is ERbeta1 alone of the biological status of individual breast cancers, and hence in predicting their response to endocrine therapy.

Wild-type oestrogen receptor beta (ERbeta1) mRNA and protein expression in Tamoxifen-treated post-menopausal breast cancers.

This study has tested the hypothesis that comparison of protein and mRNA expression for ERalpha and ERbeta1 by human breast cancers provides novel information relating to the clinical and pathological characteristics of human breast cancers. Expression of ERalpha and ERbeta1 was identified in 167 invasive cancers from postmenopausal women treated only with endocrine therapy. The cohort included 143 cases receiving only adjuvant Tamoxifen following surgery. ERalpha and ERbeta1 expression was analysed by immunohistochemistry and reverse transcription RT-PCR and compared with clinical progression of individual cancers. ERalpha protein was closely associated with the corresponding RNA detected by RT-PCR (Chi-square, P<0.001). In contrast, ERbeta1 protein and mRNA were inconsistent. Although an association was identified between ERalpha and ERbeta mRNAs (Chi-square, P<0.001) and between ERalpha protein and ERbeta1 mRNA (Chi-square, P<0.027), no association was identified for the ERalpha and ERbeta1 proteins detected by immunohistochemistry. ERbeta1 was not associated with outcome. However, in the absence of ERalpha, ERbeta1 protein expression was associated with elevated cell proliferation. There was a trend for the ERbeta1 protein-positive cases to have a worse outcome, both within the group as a whole as well as within the ERalpha-positive Tamoxifen-treated cases. This study has confirmed the hypothesis that expression of ERalpha is an important determinant of breast cancer progression, and has further demonstrated that ERbeta1 may play a role in the response of breast cancers to endocrine therapy.

Early carotid surgery in acute stroke: a multicentre randomised pilot study.

BACKGROUND: Standard practice has been to delay carotid endarterectomy (CEA) for 2 months following acute stroke to avoid a perceived risk of cerebral haemorrhage. We investigated whether early CEA reduces early recurrent stroke and improves outcome in partial anterior circulation infarction (PACI). METHODS: Patients with PACI and a Barthel score of >18 before stroke underwent carotid duplex and CT imaging within 7 days of stroke. Forty consenting patients fit for surgery with greater than 70% ipsilateral carotid stenosis were randomised, 19 to 'early' (within 24 h) and 21 to 'delayed' surgery (at 8 weeks). Modified Rankin and Barthel scores were recorded at 1 week, 2 months, 6 and 12 months. RESULTS: Rankin scores improved more rapidly following 'early' surgery to a score of 1 (0-4) at 2 and 6 months compared with 2.5 and 2 (1-4), respectively, for delayed surgery (p < 0.05). Barthel scores were also significantly improved following 'early' CEA at 7 days but both groups reached a median score of 20 by 2 months. Four 'delayed' and 3 'early' patients suffered extension or recurrence of neurological deficits with 1 death in each group. CONCLUSIONS: Early CEA within 7 days of ischaemic stroke improved functional outcome with earlier hospital discharge. A large multicentre study is needed to exclude the possibility that 'early' CEA increases the risk of cerebral haemorrhage or death.

Increased risk of malignant progression in benign proliferating breast lesions defined by expression of heat shock protein 27.

Heat shock protein 27 (hsp-27) is a regulator of oestrogen receptor (ER) expression and a modulator of intracellular homeostasis. In this laboratory, Shaaban et al demonstrated the importance of ER-alpha, together with Ki67, in enhancing the progression of benign breast lesions of defined morphological types. To better understand the mechanisms by which ER-alpha promotes breast neoplasia, this study was performed to test the hypothesis that the roles of ER-alpha and hsp-27 may be defined by their quantitative expression in proliferative breast lesions of varying histological risk. The expression of hsp-27 was identified using a specific monoclonal antibody and analysed to assess the proportion of positive epithelial cells using digitised morphometric image analysis. The expression of ER-alpha was analysed by immunohistochemistry and Western blotting in a variety of benign (HUMA121) and malignant mammary cell lines, including ER-alpha(+) (MCF7, ZR-75, T47D) and ER-alpha(-) (MDA-MB 231) breast cancer cell lines. The data confirm that, during progression from normal through proliferative breast lesions to in situ cancer, there was a significant increase in both the proportion and the optical density of the epithelial cells expressing hsp-27. The mean levels of expression ranged from 7.4% of the total number of epithelial cells in normal lobules to 25.17% of epithelial cells in hyperplasias of usual type (HUT) to 61.1% of epithelial cells in ductal carcinoma in situ (P<0.001). The study has confirmed the expression of hsp-27 to be closely associated with ER-alpha(+) expression, and that its regulated expression occurs early along the mammary oncogenic pathway, supporting the initial hypothesis. It is our proposal that the differential expression of hsp-27 modulates the phenotypic behaviour of morphologically benign epithelial cells and hence may be an important determinant in initiating, or promoting, a population of human mammary cancers.

Can undergraduate education have an effect on the ways in which pre-registration house officers conceptualise communication?

AIMS: In 1994 Manchester Medical School introduced a learner-centred course using problem-based learning (PBL), which emphasises effective communication skills. This study explored how 2 cohorts of graduates conceptualised communication within their role as pre-registration house officer (PRHOs). METHODS: Graduates from the last year of the traditional and first year of the new course were interviewed 3 months after starting work. They were asked how well their courses had prepared them for working as PRHOs and were given a specific question about communication skills. Interviews were tape-recorded, transcribed, coded and analysed. RESULTS: In all, 24 traditional course graduates (TCGs) and 23 new course graduates (NCGs) were interviewed. Traditional course graduates tended to conceptualise communication as informing people rather than as involving negotiation or having therapeutic effects. Most TCGs considered good communicators 'were born that way' and did not think communication skills could be learned. Many NCGs had a richer concept of communication that recognised communication has therapeutic benefits for patients and involved negotiation. They understood it was possible to teach communication skills. However, a minority of NCGs conceptualised communication in a similar way to TCGs. CONCLUSION: Our study suggests that the new course has helped NCGs acquire a more complex concept of communication in their role as PRHOs.

Small-group work and assessment in a PBL curriculum: a qualitative and quantitative evaluation of student perceptions of the process of working in small groups and its assessment.

The problem based learning (PBL) curriculum at Manchester emphasizes small-group work. This is supported through group assessment where students assess key aspects of their group's function. In the study described here the authors evaluated students' perceptions of both PBL group work and what a group assessment needs to assess. They aimed to produce a description of the cognitive and motivational influences on group process and unpack the ways they contribute to a successful PBL group so that the kinds of skills an effective assessment should assess could be identified. Focus groups and a questionnaire were used to generate the data. The focus group results indicate that students support PBL group work as a method of learning, and that those groups that work cooperatively are perceived as facilitating the most motivating learning environment. The students supported the assessment being summative and felt that it could be simplified to measure: behavioural skills contributing to maximizing motivation of the group process; and cognitive skills relating to the content of the group discussion. The questionnaire results also supported the use of a summative assessment of small-group work that evaluates the domains of group process and the content of the group discussion.

The contribution of genetic factors to thrombotic and bleeding outcomes in coronary patients randomised to IIb/IIIa antagonists.

Genetic variants are risk factors for coronary disease, but their role in recurrent events and in response to treatment is less clear. We genotyped genetic variants implicated in primary coronary disease in 924 Caucasians with acute coronary syndromes participating in the OPUS-TIMI16 trial of the GPIIb/IIIa antagonist orbofiban. These were the platelet glycoprotein (GP) receptors GPIIIa, GPIa, GPIbalpha; platelet ligands beta-fibrinogen and von Willebrand Factor (vWF); interleukins (IL) IL-1RN, and IL-6; adhesion proteins E-selectin and P-selectin; and metalloproteinase MMP-9. Cox modelling of all genetic variants demonstrated no significant impact on the composite endpoint (P = 0.88), which included myocardial infarction (MI), death, recurrent ischemia, urgent revascularisation and stroke, but a significant impact on recurrent myocardial infarction alone (chi(2) = 20.4, 10 df, P = 0.04). There was a significant interaction of the polymorphisms with orbofiban treatment influencing bleeding outcomes (P = 0.004). Thus, genetic polymorphisms may be associated with subsequent myocardial infarction, and may also be associated with treatment-associated bleeding among coronary patients.

Students' conceptual model of a good community attachment.

BACKGROUND: In 1994, Manchester University Medical School introduced a new integrated curriculum using problem-based learning and which places an increased emphasis on community-based education. AIMS: Students commonly use a particular label ("a good GP" (general practitioner)) to describe a positive experience in the community. The purpose of the study was to explore what students mean by "a good GP" and how this relates to their perceptions of the value of the community aspect of the course. METHOD: Three single-year focus groups were run with year 3, 4 and 5 students. A model was then derived which was explored and checked against the views of a cross-year focus group. RESULTS: A theoretical model based on student conceptualization of "a good GP" was developed. "A good GP" was found to consist of the GP as a teacher, as a role model and as an indicator of a positive learning environment. With regard to "good teacher", students felt that the GP's enthusiasm about teaching and involving the student in an active learning process was important. For "good role model", students emphasized communication skills and non-judgmental attitudes. With regard to "good learning environment", a friendly atmosphere, variety of activities, and flexibility shown by the staff of the health centre were important. CONCLUSIONS: Students hold a complex conceptual model of "a good GP" which the label does not convey. We suggest that for evaluations of student experiences it is important to explore in depth what students mean by particular terms or labels.

How well prepared are graduates for the role of pre-registration house officer? A comparison of the perceptions of new graduates and educational supervisors.

OBJECTIVE: The principal aim of undergraduate medical education is to produce competent pre-registration house officers (PRHOs). We examined and compared the perceptions of graduates and educational supervisors concerning how well prepared graduates were for their first post. METHODS: A postal questionnaire was sent to house officers who had graduated from Manchester 3 months earlier and also to educational supervisors of PRHOs in the North-west Region. The questionnaires were based on the competencies set out by the General Medical Council of the United Kingdom. RESULTS: The response rates were 66% from the graduates and 76% from the supervisors. Of the 18 broad areas of competence listed, only four were rated more than 'quite well prepared' by at least 50% of the graduates ('understanding disease processes', 'communicating effectively', 'awareness of limitations' and 'working in a team'). Similarly, more than half of educational supervisors rated graduates as more than quite competent in only three areas ('awareness of limitations', 'keeping accurate records' and 'working in a team'). Within the competencies surveyed, there were differences between the perceptions of graduates and educational supervisors on the preparedness of graduates for the skills they may require as a pre-registration house officer. CONCLUSION: Overall, given that most graduates and supervisors perceived the preparedness as 'quite well' or less, the undergraduate course had only partially met its objectives. A mismatch in ratings could be attributed to either inappropriate expectations on the part of the educational supervisors or the graduates or an inaccurate assessment by either group of respondents.

Small group learning in the final year of a medical degree: a quantitative and qualitative evaluation.

The new undergraduate medical curriculum in Manchester uses problem-based learning (PBL) throughout the course. However, the major difference from other PBL schools is that in years 3 & 4 (phase 2) the students can use clinical experience when discussing the paper cases. The process is then developed further in year 5 (phase 3), in which there are no set PBL 'triggers' and students bring their own cases to the groups for discussion. In this study, we have explored what happens in the phase 3 (year 5) group sessions and how the students view them. A questionnaire and focus groups were used to generate data, from which a model was developed of what happens in a 'good' group session. The data suggest that most groups run on a case-presentation and discussion format, most commonly about clinical management and diagnosis. Students want tutors to act as an expert resource and to be flexible in allowing students to direct the discussions. University guidance about the group sessions was not generally used.

Swallowing and prevention of complications.

Dysphagia occurs in up to half of patients following a stroke. In most, it is transient with only about 1 in 10 of patients having any swallowing problems at 6 months. Persistent dysphagia may be due to lack of bilateral cerebral hemisphere representation of the oral and pharyngeal musculature involved in swallowing. Thus, the unaffected hemisphere is unable to take over the function of the damaged side. Beside assessment is not a good predictor of aspiration on videofluoroscopy, but measurement of oxygen saturation may improve this. Nevertheless, clinical detection of dysphagia may be the more powerful predictor of an increased mortality and morbidity, including pneumonia, water depletion and poor nutrition. Dysphagia is also closely related to poor nutrition following stroke, but we do not know whether feeding support will improve outcome. Major trials are on-going.

Perioperative antibiotic use in high-risk penetrating hollow viscus injury: a prospective randomized, double-blind, placebo-control trial of 24 hours versus 5 days.

BACKGROUND: The purpose of this study was to compare the safety and therapeutic efficacy of a 24-hour versus 5-day course of ampicillin/sulbactam for the prevention of postoperative infections in high-risk patients sustaining hollow viscus injury from penetrating abdominal trauma. METHODS: A total of 317 patients from four Level I trauma centers with penetrating abdominal injuries and at least one hollow viscus perforation each received one preoperative and three postoperative doses of ampicillin/sulbactam 3 g intravenously. After receiving 24 hours of unblinded ampicillin/sulbactam, patients were then randomized into one of two groups. Group 1 received 4 additional days of blinded ampicillin/sulbactam (5 days total of antibiotic), and Group 2 received 4 days of placebo (24 hours of antibiotic). Patients were assessed postoperatively for occurrence of deep surgical-site infections (intra-abdominal abscess, fasciitis, and peritonitis) and superficial (wound) surgical-site infections. Development of nonsurgical-site infections (e.g., pneumonia, urinary tract infection, phlebitis, and cellulitis) was also recorded. Continuous variables were analyzed by analysis of variance and discrete variables by the Cochran-Mantel-Haenszel chi2 test. Multivariate logistic regression analyses were also performed to identify independent risk factors for postoperative infection. RESULTS: A total of 159 patients were randomized into Group 1, and 158 patients were randomized into Group 2. The Injury Severity Score and penetrating abdominal trauma index were 18+/-8 and 21+/-13, respectively, for Group 1 and 18+/-9 and 20+/-15, respectively, for Group 2. A total of 162 (51%) patients sustained one or more colon injuries (82 in Group 1 and 80 in Group 2). There were 16 (10%) surgical-site infections in Group 1 and 13 (8%) surgical-site infections in Group 2 (p = 0.74). Group 1 patients experienced 17 (11%) nonsurgical-site infections, whereas Group 2 had 32 (20%) nonsurgical-site infections. This difference, however, was not statistically significant (p = 0.16). Only the total number of blood units transfused and the presence of a PATI score greater than or equal to 25 were found to be independently associated with the development of a postoperative surgical- and nonsurgical-site infections (p = 0.001 and p = 0.003, respectively). Of note, the presence of a colon injury was not found to be an independent risk factor (p = 0.11) for either surgical or nonsurgical site postoperative infection in our study. CONCLUSION: High-risk patients with colon or other hollow viscus injuries from penetrating abdominal trauma are at no greater risk for surgical-site or nonsurgical-site infection when treated with only a 24-hour course of a broad-spectrum antibiotic.