Verocytotoxin Escherichia coli-Associated Haemolytic Uraemic Syndrome.

Aims To describe laboratory data on clinical human Verotoxigenic E. coli (VTEC) strains causing haemolytic uraemic syndrome (HUS) and to characterise the VTEC strains, thus contributing to risk mitigation to decrease HUS incidence in Ireland. Methods Laboratory characterisation was performed on isolates from 52 VTEC-associated HUS cases identified in the National clinical VTEC Reference Laboratory (NRL-VTEC) for the years 2012-2014. Data were analysed with respect to age, gender, serogroup and verotoxin type and subtype. Results 52/83 (62.6%) culture positive HUS cases were identified from laboratory data; 30 (57.7%) cases occurred in females. Seven HUS-associated serogroups and eleven patterns of verotoxin subtypes are described. Conclusion Ireland has the highest incidence of VTEC infection in Europe and a variety of VTEC serogroups causing clinical infection, suggesting any viable VTEC may potentially cause HUS. A broad diagnostic approach, to detect uncommon serotypes, should be considered when analysing clinical and food samples for VTEC.

TPM3 deletions cause a hypercontractile congenital muscle stiffness phenotype.

OBJECTIVE: Mutations in TPM3, encoding Tpm3.12, cause a clinically and histopathologically diverse group of myopathies characterized by muscle weakness. We report two patients with novel de novo Tpm3.12 single glutamic acid deletions at positions ΔE218 and ΔE224, resulting in a significant hypercontractile phenotype with congenital muscle stiffness, rather than weakness, and respiratory failure in one patient. METHODS: The effect of the Tpm3.12 deletions on the contractile properties in dissected patient myofibers was measured. We used quantitative in vitro motility assay to measure Ca(2+) sensitivity of thin filaments reconstituted with recombinant Tpm3.12 ΔE218 and ΔE224. RESULTS: Contractility studies on permeabilized myofibers demonstrated reduced maximal active tension from both patients with increased Ca(2+) sensitivity and altered cross-bridge cycling kinetics in ΔE224 fibers. In vitro motility studies showed a two-fold increase in Ca(2+) sensitivity of the fraction of filaments motile and the filament sliding velocity concentrations for both mutations. INTERPRETATION: These data indicate that Tpm3.12 deletions ΔE218 and ΔE224 result in increased Ca(2+) sensitivity of the troponin-tropomyosin complex, resulting in abnormally active interaction of the actin and myosin complex. Both mutations are located in the charged motifs of the actin-binding residues of tropomyosin 3, thus disrupting the electrostatic interactions that facilitate accurate tropomyosin binding with actin necessary to prevent the on-state. The mutations destabilize the off-state and result in excessively sensitized excitation-contraction coupling of the contractile apparatus. This work expands the phenotypic spectrum of TPM3-related disease and provides insights into the pathophysiological mechanisms of the actin-tropomyosin complex.

Verotoxigenic Escherichia coli transmission in Ireland: a review of notified outbreaks, 2004-2012.

Verotoxigenic Escherichia coli (VTEC) are significant for their low infectious dose, their potential clinical severity and the frequency with which they generate outbreaks. To describe the relative importance of different outbreak transmission routes for VTEC infection in Ireland, we reviewed outbreak notification data for the period 2004-2012, describing the burden and characteristics of foodborne, waterborne, animal contact and person-to-person outbreaks. Outbreaks where person-to-person spread was reported as the sole transmission route accounted for more than half of all outbreaks and outbreaks cases, most notably in childcare facilities. The next most significant transmission route was waterborne spread from untreated or poorly treated private water supplies. The focus for reducing incidence of VTEC should be on reducing waterborne and person-to-person transmission, by publicizing Health Service Executive materials developed for consumers on private well management, and for childcare facility managers and public health professionals on prevention of person-to-person spread.

Infant botulism due to C. butyricum type E toxin: a novel environmental association with pet terrapins.

We describe two cases of infant botulism due to Clostridium butyricum producing botulinum type E neurotoxin (BoNT/E) and a previously unreported environmental source. The infants presented at age 11 days with poor feeding and lethargy, hypotonia, dilated pupils and absent reflexes. Faecal samples were positive for C. butyricum BoNT/E. The infants recovered after treatment including botulism immune globulin intravenous (BIG-IV). C. butyricum BoNT/E was isolated from water from tanks housing pet 'yellow-bellied' terrapins (Trachemys scripta scripta): in case A the terrapins were in the infant's home; in case B a relative fed the terrapin prior to holding and feeding the infant when both visited another relative. C. butyricum isolates from the infants and the respective terrapin tank waters were indistinguishable by molecular typing. Review of a case of C. butyricum BoNT/E botulism in the UK found that there was a pet terrapin where the infant was living. It is concluded that the C. butyricum-producing BoNT type E in these cases of infant botulism most likely originated from pet terrapins. These findings reinforce public health advice that reptiles, including terrapins, are not suitable pets for children aged <5 years, and highlight the importance of hand washing after handling these pets.

Molecular characterization of Irish E. coli O157:H7 isolates of human, bovine, ovine and porcine origin.

AIMS: To determine the degree of relatedness between isolates of Escherichia coli O157:H7 of human, bovine, ovine and porcine origin. METHODS AND RESULTS: Escherichia coli O157:H7 isolates were compared using (i) PFGE XbaI patterns, (ii) PCR profiles of virulence genes and (iii) the DNA sequences of genes reported to play a role in pathogenicity. The 77 E. coli O157:H7 isolates demonstrated 49 different PFGE patterns of which, eight were common to multiple isolates, and the remaining 41 were distinct. Isolates of different origin did not correlate, except for one cluster consisting of two human and two beef isolates. The majority of animal isolates had the same PCR profiles of virulence genes as those isolated from clinical patients. Single nucleotide polymorphisms (SNPs) were identified in the sequence of a 255-bp region of the vtx2 subunit A gene. CONCLUSIONS: Six SNPs were detected in the vtx2A gene, defining four different haplotypes. One nonsynonymous substitution encoded for an amino acid change from glutamic to aspartic acid. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate that although E. coli O157:H7 isolates of differing origin were distinct by PFGE, the DNA sequences of the main virulence genes associated with human clinical illness were conserved.

EEG sleep evaluation of depression in borderline patients.

In this study the sleep of borderline patients and patients with primary nondelusional depression showed sleep continuity disturbance and greater REM activity and density (particularly during the first REM period) than that of normal control subjects. First-night REM latencies were more variable in the borderline than in the depressed group, but by the second night both groups showed shorter REM latencies than the controls. The similarities in EEG sleep suggest a relationship between borderline disorder and the affective spectrum and cast doubt on the definition of the borderline disorder as a pure character type.

Breath hydrogen and methane: poor indicators of apparent digestion of soy fiber.

To examine whether end-alveolar breath hydrogen and methane could be used as indicators of fiber digestion in humans, 16 male subjects were fed four fiber-free, complete liquid diets with 0, 30 g (heat processed), 30 g, and 60 g/day soy polysaccharide. Breath hydrogen was measured hourly and breath methane every 4 h on days 6 and 8 of each study period. Feces were collected, homogenized, dried, and analyzed for neutral detergent fiber (NDF). NDF in diets was determined and apparent NDF digestibility calculated. NDF from soy was extensively fermented, greater than 80%, on the fiber-containing diets. No significant relationship was found between breath-gas excretion and fiber digestion, although breath-gas values varied greatly. Breath hydrogen and methane were not significantly different when subjects consumed diets containing 0, 30, or 60 g soy polysaccharide.

The impact of blood culture reporting and clinical liaison on the empiric treatment of bacteraemia.

AIMS: To assess the impact of blood culture results and early clinical liaison on the treatment of patients with bacteraemia. METHODS: 123 patients with significant positive blood cultures were followed over a nine month period in a 620 bed teaching hospital. The impact of early blood culture reporting and clinical liaison on the cost and appropriateness of treatment was assessed. RESULTS: Empiric treatment was started before the Gram stain result in 107 (87%) patients. Treatment was altered on the basis of the Gram stain result in 39 (36%) of these patients, and on culture and sensitivity results in 53 (50%). The spectrum of antibiotic treatment was narrowed in 58 (54%) of these; 20 (19%) on Gram stain result alone. This resulted in a 42% reduction in daily antibiotic costs in patients who had received empiric treatment. Empiric treatment did not follow the hospital antibiotic policy in 49 (46%) of the patients treated. In patients where empiric treatment was not in accordance with hospital policy, 21 (44%) had an isolate resistant to the empiric treatment used; while in patients who received agents in accordance with hospital policy only one (1.7%) had a resistant isolate (p < 0.05). Patients who died (11 (9%)) were less likely to have received empiric treatment in accordance with the antibiotic policy, although this did not reach statistical significance (p = 0.1). CONCLUSION: Early reporting of Gram stain results from blood cultures, combined with early clinical liaison, results in more rational and cost effective treatment.

A twelve-year review of central nervous system bacterial abscesses; presentation and aetiology.

OBJECTIVES: To review and document the changing patterns in diagnosis, causes and treatment of bacterial infections of the central nervous system (CNS) in a national neurosurgical unit only in patients from whom a specimen was obtained for culture. METHODS: The case notes, radiological results and laboratory records of all 163 patients in our institution who underwent a neurosurgical procedure between 1988 and 2000 for a CNS abscess in a national center were reviewed retrospectively. Those patients from whom there were no operative specimens (i.e. neurosurgical intervention was not performed) and who were treated empirically were excluded, as were patients with mycobacterial infection. RESULTS: The mean age of the 163 patients was 35.2 years. Headache, pyrexia and an altered mental state were the commonest presentations. The frontal lobe was the commonest anatomical site (62 patients, 38%) and the majority of abscesses occurred following community infections such as sinusitis and mastoiditis; no primary source could be identified in 32 (20%) patients. Bacteria were isolated from 73% of patients and polymicrobial infections occurred in 29 (17.7%) patients. Anaerobes accounted for only 13.6% of isolates and methicillin-resistant Staphylococcus aureus (MRSA) was isolated on five occasions, all in the last five years of this review. Sixteen (9.8%) patients died prior to discharge or transfer back to the original referring hospital and 18 (11%) patients developed epilepsy. CONCLUSION: There was a relatively high incidence of polymicrobial infection but the number of specimens with anaerobes was small, which may be because of the use of empiric metronidazole before surgical intervention. Most infections were community-acquired and responded well to a combination of surgical drainage and antibiotic therapy. The emergence of MRSA in this group of patients is, however, worrying.

Experience with Enterobacter bacteraemia in a Dublin teaching hospital.

In a review of Enterobacter bacteraemia in a 600-bedded teaching hospital, 22 episodes were identified in 20 patients over a 2-year period. An evaluation of risk factors suggested an association between Enterobacter infection and the presence of central venous catheters or use of H-2 receptor antagonists. These factors together with previous exposure of the patient to gentamicin, and prolonged stay in the intensive care unit, increased the likelihood of gentamicin-resistant Enterobacter bacteraemia. This finding has implications for the choice of antibiotic regimen in the empirical treatment of suspected Gram-negative septicaemia.

Investigation of an outbreak of gastroenteritis caused by Norwalk-like virus, using solid phase immune electron microscopy.

In February 1993, 95 persons (47 patients and 48 staff members) were affected by an hospital outbreak of viral gastroenteritis. Using direct electron microscopy (EM) the causative agent was identified as a small round structured virus. This was confirmed as a Norwalk-like virus using solid phase immune electron microscopy (SPIEM). Of 94 stool samples examined, 12 (13%) samples containing small round structured viruses (SRSV) were SPIEM positive for Norwalk-like virus. A further 25 (27%) samples contained small round featureless virus (SRFV) identified by direct EM and were negative on SPIEM. The illness was characterized by preceding influenza-like symptoms in 76% of cases followed by vomiting (76%), diarrhoea (79%) and abdominal pain (79%). One fatality was recorded. The outbreak lasted for 15 days, with a peak incidence of new cases amongst patients and staff occurring on day 5. It was controlled through a combination of ward closures, patient cohorting, suspension of duties for affected staff and disinfection procedures. Difficulties were encountered in the education of staff and in the implementation of environmental control measures. Screening of hospital catering services and a case control study, carried out among affected staff members, failed to identify a foodborne source. Consumption of tap water in the hospital was commoner among affected staff members than among controls, but this did not reach significance (P = 0.1).

Enteral tube feeding in the community: survey of adult patients discharged from a Dublin hospital.

BACKGROUND AND AIMS: No previous study has examined the state of patients on enteral tube feeding in the community in the Republic of Ireland. METHODS: Fifty adult patients discharged from a Dublin hospital on enteral tube feeding were assessed retrospectively. RESULTS: Sixty-six per cent of the sample were over 65 years of age. Patients required enteral tube feeding as a consequence of swallowing difficulties caused by stroke (46%) or cancer of the head and neck (24%). Most patients were on full nutritional support and, in total, had spent over 49 years tube feeding in the community. Geriatric stroke patients were found to have poor functional ability and nutritional assessment proved difficult to carry out on many of these patients. Problems encountered with feeding included blocked tubes (30%), infected stoma sites (16%), and logistical problems regarding feed and equipment. Nutritional follow-up was not routine in patients with poor mobility, and 55% of patients on long-term tube feeding had not been reviewed by a dietitian in over 1 year. Patients had little faith in their general practitioner's knowledge of enteral feeding. CONCLUSIONS: While patients and families appear to cope remarkably well with tube feeding in the community, more support is necessary to ensure appropriate feeding and to monitor the nutritional status of these patients.

Occurrence of Campylobacter in retail foods in Ireland.

A surveillance study was carried out to determine the prevalence of Campylobacter in a range of retail foods purchased in three Irish cities over a 20-month period between March 2001 and October 2002. In total 2391 food samples were analysed during this period. Campylobacter was isolated from 444 raw chicken (49.9%), 33 turkey (37.5%) and 11 duck samples (45.8%). Lower isolation rates of 7/221 (3.2%), 10/197 (5.1%) and 31/262 (11.8%) were observed for raw beef, pork and lamb, respectively. One sample of pork paté from 120 samples analysed (0.8%) was Campylobacter-positive. A total of three shellfish samples (oysters) from 129 raw specimens examined (2.3%) were found to contain Campylobacter. Low prevalences of the organism (0.9%) were also isolated from fresh mushrooms. Of 62 raw bulk tank milk samples analysed, Campylobacter was recovered in a single sample (1.6%). Campylobacter was not detected in any of the comminuted pork puddings, prepared vegetables and salads, retail sandwiches or cheeses made from unpasteurised milk. In total, 543 Campylobacter were isolated from all of the food samples analysed, of which 453 (83.4%) were confirmed as Campylobacter jejuni and the remaining 90 (16.6%) as Campylobacter coli.

Community and hospital acquired Staphylococcus aureus septicaemia: 115 cases from a Dublin teaching hospital.

Despite advances in diagnostic techniques and antimicrobials, septicaemia due to Staphylococcus aureus remains a common clinical problem with a significant mortality. We retrospectively compared community and hospital acquired cases of S. aureus septicaemia occurring in our 600 bed teaching hospital over a 30 month period. Of 110 episodes 32 (29%) were community acquired and 78 (71%) hospital acquired. A likely primary source was identified in 14 (44%) of community acquired cases and in 73 (94%) of hospital acquired cases. A secondary focus of infection was more common in community acquired cases (17, 53%) than hospital acquired cases (5, 6%). Mortality was significantly higher in community acquired cases (22% vs. 6%). An association was also found between the presence of endocarditis and increased mortality, although this did not reach significance. We also compared hospital acquired septicaemia due to methicillin sensitive and methicillin resistant S. aureus found a significantly higher mortality in the methicillin resistant group (22% vs. 3%, P < 0.05). S. aureus septicaemia remains an important cause of morbidity and mortality, particularly when associated with secondary foci of infection. This study also emphasises the importance of control of methicillin resistant strains in hospital.

Bowel function of healthy men consuming liquid diets with and without dietary fiber.

The importance of the level of dietary fiber intake on bowel function was measured in 16 healthy young males consuming self-selected and liquid enteral diets. Subjects consumed liquid Ensure as their sole nutrient source plus 0 (diet a), 30 (diet c), and 60 (diet d) g/day soy fiber, a fiber source high in hemicellulose that was added to the Ensure. Further, to examine whether heat processing affects the physiologic action of fiber, subjects consumed Enrich, an enteral formula similar to Ensure, which contains 30 g of the same soy fiber (diet b). The four diets were consumed in randomized order each for 10 days. Daily wet stool weight averaged 144.6 g on the self-selected diet and decreased significantly to 67.3 g when Ensure was consumed alone. Average stool weights on diets (b), (c), and (d) were 114.6, 100.2, and 150.3 g/day, respectively. Average fecal dry weights for the four diets were 19.1, 28.7, 25.0, and 30.3 g/day for (a-d), respectively. Gastrointestinal transit time, as measured with radiopaque pellets, was longest on the Ensure diet, 72.4 hr, and approximately 2 days on the fiber-supplemented diets and the self-selected diet. Thus, soy fiber's physiologic effect on laxation was not changed by heat processing. Also, although stool weights were larger on higher fiber intakes, transit rates were similar on all the fiber-containing diets.

Bioequivalence of a propylene glycol-based liquid dapsone preparation and dapsone tablets.

The bioequivalence of a proprietary liquid dapsone preparation and commercially available dapsone tablets was studied. Twelve adult volunteers received dapsone doses with 8 oz of water one to two hours after their usual breakfast. Each subject received an initial 100-mg dose of a propylene glycol-based liquid preparation of dapsone and, two weeks later, a 100-mg dapsone tablet (both from Jacobus Pharmaceutical Company, Princeton, NJ). Blood samples were collected before and at intervals up to 96 hours after the administration of each dose. Serum dapsone concentrations were determined by high-performance liquid chromatography, and pharmacokinetic values were calculated by model-independent analysis. The area under the concentration-versus-time curve and the maximum serum concentration for the two formulations met the criteria for bioequivalence. Time to maximum serum concentration tended to be lower for the liquid, but not significantly. The liquid and tablet formulations of dapsone studied were found to be bioequivalent and may be used interchangeably.

Pharmacokinetics of penicillin G procaine versus penicillin G potassium and procaine hydrochloride in horses.

OBJECTIVE: To compare the pharmacokinetics of penicillin G and procaine in racehorses following i.m. administration of penicillin G procaine (PGP) with pharmacokinetics following i.m. administration of penicillin G potassium and procaine hydrochloride (PH). ANIMALS: 6 healthy adult mares. PROCEDURE: Horses were treated with PGP (22,000 units of penicillin G/kg of body weight, i.m.) and with penicillin G potassium (22,000 U/kg, i.m.) and PH (1.55 mg/kg, i.m.). A minimum of 3 weeks was allowed to elapse between drug treatments. Plasma and urine penicillin G and procaine concentrations were measured by use of high-pressure liquid chromatography. RESULTS: Median elimination phase half-lives of penicillin G were 24.7 and 12.9 hours, respectively, after administration of PGP and penicillin G potassium. Plasma penicillin G concentration 24 hours after administration of penicillin G potassium and PH was not significantly different from concentration 24 hours after administration of PGP. Median elimination phase half-life of procaine following administration of PGP (15.6 hours) was significantly longer than value obtained after administration of penicillin G potassium and PH (1 hour). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that i.m. administration of penicillin G potassium will result in plasma penicillin G concentrations for 24 hours after drug administration comparable to those obtained with administration of PGP Clearance of procaine from plasma following administration of penicillin G potassium and PH was rapid, compared with clearance following administration of PGP.

Susceptibility of urinary pathogens in a Dublin teaching hospital.

The range and resistance patterns of organisms causing urinary tract infections (UTI) vary with time and place. A prospective study of midstream urine (MSU) specimens, received over a 3 month period, was therefore undertaken. The antibiotic sensitivities of 528 isolates from 196 domiciliary and 332 hospitalised patients with significant bacteriuria (> 10(5) organisms/ml) were determined using the modified Stokes method. Escherichia coli accounted for 79% of domiciliary isolates and 57% in hospitalised patients. Gram positive organisms causing UTI have become increasingly common and were isolated from 8% and 15% of domiciliary and hospitalised patients respectively. Resistance levels for co-amoxiclav (Augmentin) were low (7% domiciliary, 14% hospitalised). However 46 Gram negative isolates (10%) had intermediate sensitivities to co-amoxiclav on disc testing. Breakpoint testing showed 89% of these to be sensitive at the urinary breakpoint but only 52% were sensitive at the systemic breakpoint. Forty nine percent of E. coli from hospital specimens were resistant to pipercillin, due to TEM-1 beta lactamase production. A 6% resistance level to ciprofloxacin in domiciliary E. coli is considerably higher than previous reports and gives cause for concern. Gentamicin resistance was found in 4% of Gram negative hospital isolates, a finding of some significance in the empiric treatment of septicaemia of urinary tract origin.

Lower prevalence of anti-hepatitis C antibody in dialysis and renal transplant patients in Ireland.

It is well recognised that haemodialysis and renal transplant patients are at increased risk of developing non-A, non-B hepatitis. Recently the genome of hepatitis C virus (HCV), the major causative agent for non-A, non-B hepatitis, has been isolated. Anti-HCV seroprevalence was assessed in all haemodialysis patients (266) in Ireland who in March 1990 had been dialysed for at least 6 months. For comparative purposes, 272 patients who had functioning renal transplants for greater than 6 months were also studied. Potential risk factors such as age, number of blood transfusions and time on dialysis were evaluated. The prevalence of HCV infection as evidenced by antibody detection was only 1.1% for transplant and 1.7% for haemodialysis patients. This compares to a reported incidence of between 10% and 50% found elsewhere. Two of the 5 anti-HCV positive haemodialysis patients and 2 of the 3 transplant patients had biochemical evidence of liver disease. From stored sera it was possible to ascertain when patients acquired HCV. Whether the very low prevalence of anti-HCV in Irish patients is due to the low prevalence of the virus in the general population, the policy of non reimbursement of blood donors, genetic or other factors, remains to be determined.