Phenotypic and genotypic profiling of antimicrobial resistance in enteric Escherichia coli communities isolated from finisher pigs in Australia.

OBJECTIVE: To assess herd-to-herd variation in antimicrobial resistance phenotypes and associated antimicrobial resistance genes (ARGs) in faecal commensal Escherichia coli communities isolated from Australian slaughter-age pigs. METHODS: Hydrophobic grid-membrane filtration (HGMF) was used to screen populations of E. coli isolated from faecal samples obtained from pigs prior to or at slaughter. Multiplex PCRs were applied to the pooled DNA extracted from the samples to identify specific ARGs. METHODS: Pooled faecal samples from 30 finishers, from 72 different Australian pig farms, produced 5003 isolates for screening. HGMF techniques and image analysis were used to confirm E. coli resistance phenotypes to four antimicrobial agents (ampicillin, gentamicin, florfenicol and ceftiofur) using selective agars. Multiplex PCRs were performed on DNA from pooled samples for 35 ARGs associated with seven chemical classes. RESULTS: The prevalence of E. coli isolates showing no resistance to any of the drugs was 50.2% (95% confidence interval (CI) 41.8-58.6%). Ceftiofur resistance was very low (1.8%; CI 0.8-3.9%) and no ARGs associated with 3rd-generation cephalosporin resistance were detected. By contrast, ampicillin (29.4%, CI 22.8-37.0%), florfenicol (24.3%, CI 17.8-32.3%) and gentamicin (CI 17.5%, 10.7-27.2%) resistance prevalence varied greatly between farms and associated ARGs were common. The most common combined resistance phenotype was ampicillin-florfenicol. CONCLUSION: The use of registered antimicrobials in Australian pigs leads to the enteric commensal populations acquiring associated ARGs. However, despite a high intensity of sampling, ARGs imparting resistance to the critically important 3rd-generation cephalosporins were not detected.

Antimicrobial resistance and virulence gene profiles in multi-drug resistant enterotoxigenic Escherichia coli isolated from pigs with post-weaning diarrhoea.

This study aimed to characterize antimicrobial resistance and virulence genes in multi-drug resistant enterotoxigenic Escherichia coli (ETEC) isolates (n=117) collected from porcine post-weaning diarrhoea cases in Australia (1999-2005). Isolates were serotyped, antibiogram-phenotyped for 12 antimicrobial agents and genotyped by PCR for 30 plasmid-mediated antimicrobial resistance genes (ARGs), 22 intestinal and 38 extraintestinal E. coli virulence genes (VGs). Nine serogroups were identified, the most prevalent being O149 (46.2%), O141 (11.2%) and Ont (31.6%). None of the isolates showed resistance to ceftiofur or enrofloxacin and 9.4% were resistant to florfenicol. No corresponding extended-spectrum/AmpC ß-lactamase, fluoroquinolone or floR ARGs were detected. An antimicrobial resistance index (ARI) was calculated from the combined data with a weighting for each antimicrobial agent dependent upon its significance to human health. Serogroup O141 isolates had a significantly higher ARI due to an elevated prevalence of aminoglycoside ARGs and possession of more virulence genes (VGs), including ExPEC or EHEC adhesins (bmaE, sfa/focDE, fimH, ihA) in toxin-producing strains that lacked the normally associated F4 and F18 fimbriae. Few associations between ARGs and VGs were apparent, apart from tetC, sfa/focDE and ompT which, for a sub-set of O141 isolates, suggest possible plasmid acquisition from ExPEC. The multi-drug resistant ETEC ARG/VG profiles indicate a high probability of considerable strain and plasmid diversity, reflecting various selection pressures at the individual farm level rather than emergence and lateral spread of MDR resistant/virulent clones.

TGF-beta1 interactome: metastasis and beyond.

The ubiquitous cytokine transforming growth factor-beta1 (TGF-beta1) is one of the most potent metastatic inducers. Functional interactomic mapping using high-throughput proteomic and genomic data provides valuable insights into the regulation of tumor suppressive and metastatic attributes of TGF-beta1. Polarity changes of the TGF-beta1 interactome at a given time contributes to these contrasting effects. Differential expression profiles of pivotal interactomic nodes contribute to these polarity changes. These insights are of immense value in the development of effective cancer therapeutics. Moreover, TGF-beta1 interactomic nodes are useful in discovering novel cancer biomarkers. This review describes an initial version of the TGF-beta1 interactome in relation to tumor progression and metastasis. Thus, this review embodies an important step towards the mapping of comprehensive and individualized TGF-beta1 interactomes that will assist in the development of personalized cancer therapeutics.

The coral reef crisis: the critical importance of<350 ppm CO2.

Temperature-induced mass coral bleaching causing mortality on a wide geographic scale started when atmospheric CO(2) levels exceeded approximately 320 ppm. When CO(2) levels reached approximately 340 ppm, sporadic but highly destructive mass bleaching occurred in most reefs world-wide, often associated with El Niño events. Recovery was dependent on the vulnerability of individual reef areas and on the reef's previous history and resilience. At today's level of approximately 387 ppm, allowing a lag-time of 10 years for sea temperatures to respond, most reefs world-wide are committed to an irreversible decline. Mass bleaching will in future become annual, departing from the 4 to 7 years return-time of El Niño events. Bleaching will be exacerbated by the effects of degraded water-quality and increased severe weather events. In addition, the progressive onset of ocean acidification will cause reduction of coral growth and retardation of the growth of high magnesium calcite-secreting coralline algae. If CO(2) levels are allowed to reach 450 ppm (due to occur by 2030-2040 at the current rates), reefs will be in rapid and terminal decline world-wide from multiple synergies arising from mass bleaching, ocean acidification, and other environmental impacts. Damage to shallow reef communities will become extensive with consequent reduction of biodiversity followed by extinctions. Reefs will cease to be large-scale nursery grounds for fish and will cease to have most of their current value to humanity. There will be knock-on effects to ecosystems associated with reefs, and to other pelagic and benthic ecosystems. Should CO(2) levels reach 600 ppm reefs will be eroding geological structures with populations of surviving biota restricted to refuges. Domino effects will follow, affecting many other marine ecosystems. This is likely to have been the path of great mass extinctions of the past, adding to the case that anthropogenic CO(2) emissions could trigger the Earth's sixth mass extinction.

Antimicrobial use in the Australian pig industry: results of a national survey.

OBJECTIVE: To describe how various antimicrobials are used in commercial pig herds in Australia and for what disease conditions. PROCEDURE: Managers of large pig herds (> 200 sows) across Australia and their veterinarians participated in an internet-based survey in 2006. Questions were asked about herd management, the occurrence of bacterial diseases and the type and frequency of antimicrobial use. An antimicrobial usage index for each herd was derived as a summary of the risk of selection for antimicrobial resistance. Relationships between responses were explored with univariate and multivariate analysis. RESULTS: Responses were received for 197 herds estimated to represent at least 51% of all large pig herds in Australia. Most piggeries relied on drugs of low importance in human medicine (e.g. tetracyclines, penicillins and sulfonamides). For the two drugs of high importance in human medicine that can be legally prescribed to pigs in Australia, ceftiofur use was reported in 25% of herds and virginiamycin in none. Infections attributed to Lawsonia, Mycoplasma and Escherichia coli motivated the most use of antimicrobials. No useful association was found between management factors and the antimicrobial use index. CONCLUSION: Most antimicrobial use in the Australian pig industry is based on drugs of low importance to public health. Enhanced control of E. coli infections without reliance on antimicrobials would further reduce the risk of selecting for antimicrobial resistance relevant to public health. The amount of variation in the usage index between herds suggests that antimicrobial use should be constantly reviewed on a herd by herd basis.

Inhibition of progenitor cell proliferation in the dentate gyrus of rats following post-weaning lead exposure.

Although lead is a potent developmental neurotoxin, the effects of postnatal lead exposure on progenitor cell proliferation in the hippocampus has not been examined. Postnatal day 25 rats were fed a lead containing diet (1500 ppm lead acetate) for 30-35 days and administered bromodeoxyuridine (BrdU, 50 mg/kg, i.p.) during the last 5 days of lead exposure. Animals were killed 24 h after the last BrdU injection. Proliferation of new cells in the subgranular zone and dentate gyrus was significantly decreased in lead-exposed rats compared to control animals that ate a similar diet devoid of lead. These results suggest that postnatal lead exposure can have significant deleterious effects on progenitor cell proliferation and thus the structure and function of the hippocampus.

Treatment of osteoporosis: missed opportunities in the hospital fracture clinic.

AIM: To identify what proportion of patients who, having sustained an initial distal radial fragility fracture and a subsequent femoral neck fracture, had had their osteoporosis addressed in the interval between the two events. PATIENTS AND METHODS: The hospital electronic information system was used to identify all patients aged over 50 years treated for a distal radial fracture, in our fracture clinic, between 1995-2000. In addition all patients admitted to our hospital, during the same time period, with a femoral neck fracture were identified. RESULTS: A study cohort of 74 patients were identified. The proportion of patients who received investigation of, or treatment for, osteoporosis between their wrist and femoral neck fracture was 8% whereas 84% did not. CONCLUSIONS: Current mechanisms for identifying patients with osteoporosis before they sustain a femoral neck fracture are inadequate.

Clinical and economic benefits of ramipril: an Australian analysis of the HOPE study.

BACKGROUND: The Heart Outcomes Prevention Evaluation (HOPE) study has demonstrated that ramipril 10 mg/day for 5 years in an at-risk population results in clinically and statistically significant reductions in the occurrence of cardiovascular death, myocardial infarction (MI), stroke and revascularization procedures. The likely impact of the intervention in Australia, in terms of the number of potential events avoided and the cost per life-year saved, has previously not been determined. AIMS: To assess the clinical and economic impacts of the use of daily ramipril in the Australian at-risk population from the perspective of the public health-care budget. METHODS: The clinical benefits were calculated from endpoints used in the trial, which were converted to the 'number needed to treat'. These were then applied to the at-risk population, which was determined nationally from the relevant Australian statistics. The result of this calculation is the potential number of events avoided in Australia. The economic benefits were established by undertaking an incremental cost-effectiveness analysis. The economic model considered the clinical benefits and the costs (and cost offsets) arising from ramipril 10 mg/day therapy for 5 years. Life-years saved was determined by calculating the difference in total years survived between the ramipril and control arms of the study. Net costs divided by life-years saved is the cost per life-year saved, and this is reported in Australian dollars as the incremental cost effectiveness. RESULTS: The clinical benefits over a 5-year period were expressed as the number of potential events avoided and comprised approximately: 9188 strokes; 14 658 MI; 14 317 revascularization procedures; and 12,534 cardiovascular-related deaths, nationally. The incremental cost-effectiveness analysis showed the estimated cost per life-year saved to be 17,214 Australia dollars. CONCLUSION: The use of ramipril 10 mg/day over a 5-year period in the at-risk Australian population could prevent many thousands of cardiovascular events, including 12,534 cardiovascular-related deaths. The cost per life-year saved compares favourably to other health care interventions.

Fracture of an elastic humeral nail. A case report.

The use of elastic intramedullary nails for the treatment of diaphyseal fractures of the humerus has been associated with few complications. We report a fracture of an elastic Marchetti-Vicenzi nail used to treat a pathological fracture of the humerus. The failure of the intramedullary nail followed low-energy trauma and was presumably the end result of metal fatigue, as the original fracture had only healed after 13 months.

Lacrimal fossa block: an audit of a minimally invasive regional anaesthetic technique for endoscopic dacryocystorhinostomy (DCR).

The lacrimal fossa block (LFB), a new development to provide regional anaesthesia for endoscopic dacryocystorhinostomy, is reported. Cadaveric study showed that the block needle, inserted as described, made direct contact with the periosteum of the frontal process of the maxilla within the lacrimal fossa. This technique enables both relevant divisions of the trigeminal nerve to be anaesthetized through a single entry site and, as this injection is confined to the anterior part of the orbit, ocular complications are minimized. An audit of 66 patients has shown that this technique, combined with standard intranasal local anaesthesia, provides good intraoperative analgesia, causes minimal diplopia and has a high level of patient acceptability.

The life cycle of actin patches in mating yeast.

Actin patches are core components of the yeast actin cytoskeleton that undergo redistribution during establishment of cell polarity. Using 4D imaging, we observe the life cycle of actin patches in living yeast for the first time. We observe assembly of actin patches at sites of polarized growth, and disassembly of actin patches concomitant with movement away from those sites. The total lifetime of an actin patch is 10.9+/-4.2 seconds. These findings indicate that actin patches are labile structures, and that the localization of actin patches during establishment of cell polarity occurs by assembly of these structures at sites of polarized cell surface growth. These findings were confirmed and extended by analysis of myosin I proteins and their receptor, verprolin, proteins implicated in actin assembly in yeast. Deletion of type I myosins or their receptor has no effect on the velocity of actin patch movement. However, these mutants show a 65% reduction in number of patch movements and a three-fold increase in patch lifetime. Finally, the actin patch resident proteins Abp1p, fimbrin, and Arp2p show normal association with actin patches in myosin I and verprolin mutants. However, cofilin accumulates in abnormal 'bars' of G-actin in myo3Delta,myo5Delta and vrp1Delta strains, and Las17p/Bee1p is not associated with actin patches in vrp1Delta strains. These findings imply a multi-step process for actin patch assembly. Early events in this process, including assembly of Abp1p, fimbrin and Arp2p with F-actin, can occur throughout the cell and do not require myosin I proteins or their receptor. Later events in this process are myosin I-dependent, and are required for assembly of actin patches at sites of polarized cell surface growth.

Implementation of the STOP protocol for Stroke Prevention in Sickle Cell Anemia by using duplex power Doppler imaging.

PURPOSE: To compare the results of the nonduplex ultrasonography (US) Stroke Prevention Trial in Sickle Cell Anemia (STOP) with those of transcranial duplex power Doppler US by using the STOP protocol and to correlate abnormal transcranial Doppler findings with magnetic resonance (MR) imaging and MR angiographic findings. MATERIALS AND METHODS: One hundred twenty-five asymptomatic patients aged 2-16 years with sickle cell anemia or sickle cell-beta thalassemia were examined by using transcranial duplex power Doppler US with a 2.5-MHz transducer and classified according to STOP criteria. The results were compared with those obtained in the nonduplex STOP study. Eight of 10 patients with abnormal results, as well as one who had normal results and a subsequent stroke, were examined with MR imaging and MR angiography. RESULTS: Ten (8.0%) patients were judged to have abnormal findings by using the duplex Doppler US and STOP criteria compared with 9.4% of patients in the nonduplex US STOP study. Of the eight patients with abnormal transcranial Doppler US results who underwent MR imaging and MR angiography, six had abnormal MR imaging findings and all eight had abnormal MR angiographic findings. CONCLUSION: The STOP protocol can be reproduced by using duplex power Doppler US. Abnormal results with the STOP criteria strongly suggest vascular abnormality.

An outbreak of Yersinia enterocolitica O:8 infections associated with pasteurized milk.

In October 1995, an outbreak of Yersinia enterocolitica O:8 infections occurred in the Upper Valley of Vermont and New Hampshire. Ten patients were identified, median age 9 years (range, 6 months-44 years). Three patients were hospitalized; 1 underwent an appendectomy. Consumption of bottled pasteurized milk from a local dairy was associated with illness (matched odds ratio undefined; lower 95% confidence interval, 1.9). No deficiencies in pasteurization procedures or equipment were detected. Y. enterocolitica O:8 was isolated from 1 raw-milk sample and from a fecal sample from 1 dairy pig. The route of contamination was not determined; this outbreak likely resulted from postpasteurization contamination of milk. Dairy pigs were the most likely source of contamination. Milk bottles were likely contaminated by rinsing with untreated well water prior to filling or by other environmental routes. Educating dairy owners about Y. enterocolitica and postpasteurization contamination is necessary to prevent further outbreaks.

Tourniquet constriction exacerbates hyperalgesia-related pain induced by intradermal capsaicin injection.

BACKGROUND: When capsaicin is injected intradermally, hyperalgesia develops around the injection site. The authors observed that volunteers report painful sensations in the skin remote from the injection site during tourniquet constriction of the affected extremity. METHODS: Each volunteer received an intradermal injection of capsaicin on the volar forearm, followed by intermittent tourniquet constriction of the extremity. In some participants, the tourniquet position was rotated between different sites on the upper extremities. Laser Doppler measurements were made in the skin to measure capillary blood flow during pain magnification. RESULTS: Hyperalgesia developed in the volunteers who were tested after the capsaicin injection. Blood flow increased three times in the dermal capillaries remote from the injection site after capsaicin injection. The tourniquet-induced pain reached peak intensity soon after tourniquet inflation. Tourniquet constriction of the arm on the affected side reliably induced painful exacerbation in each person tested. The quality of the sensation was described as burning and extended across the arm in most volunteers. Only when pinprick hyperalgesia was detectable did the volunteers experience the diffuse, immediate pain sensation. The pain initiated by the tourniquet constriction likely is related to changes in skin capillary blood flow. CONCLUSIONS: Low cutaneous blood perfusion is related to the intensity of ongoing, spontaneous pain when secondary hyperalgesia is present. The specific trigger(s) have yet to be identified.