A plasma membrane Ca2+-ATPase (PMCA) from the liver fluke, Fasciola hepatica

Fasciolosis is a parasitic infection by the liver fluke Fasciola hepatica, which costs the global agricultural community over US $2 billion per year. Its prevalence is rising due to factors such as climate change and drug resistance. ATP-dependent membrane transporters are considered good potential drug targets as they are essential for cellular processes and are in an exposed, accessible position in the cell. Immunolocalisation studies demonstrated that a plasma membrane calcium ATPase (PMCA) was localised to the parenchymal tissue in F. hepatica. The coding sequence for a F. hepatica PMCA (FhPMCA) has been obtained. This sequence encodes a 1,163 amino acid protein which contains motifs which are commonly conserved in PMCAs. Molecular modelling predicted that the protein has 10 transmembrane segments which include a potential calcium ion binding site and phosphorylation motif. FhPMCA interacts with the calmodulin-like protein FhCaM1, but not the related proteins FhCaM2 or FhCaM3, in a calcium-ion dependent manner. This interaction occurs through a region in the C-terminal region of FhPMCA which most likely adopts an a-helical conformation. When FhPMCA was heterologously expressed in a budding yeast strain deleted for its PMCA (Pmc1p), it restored viability. Microsomes prepared from these yeast cells had calcium ion stimulated ATPase activity which was inhibited by the known PMCA inhibitors, bisphenol and eosin. The potential of FhPMCA as a new drug target is discussed.

Ciprofloxacin use and susceptibility of Gram-negative organisms to quinolone and non-quinolone antibiotics

A Trust strategy to reduce ciprofloxacin use was implemented at a University hospital. This study aimed to investigate whether the susceptibility of Gram-negative organisms (GNO) to alternative antimicrobials (co-amoxiclav, doxycycline, aztreonam, piperacillin/tazobactam, meropenem and gentamicin) changed, and whether there was any relationship between GNO susceptibility to these antimicrobials and ciprofloxacin usage.

Clinico-epidemiological features of infections caused by CTX-M type extended spectrum beta lactamase-producing Escherichia coli in hospitalised patients

A review of medical records of 45 of 53 hospitalised patients with positive cultures for CTX-M type ESBL-producing Escherichia coli between 01 January and 31 May 2004 was conducted. The mean age of the population studied was 73.1 (+/-14.6) years and the majority (55.6%) had been under the care of the internal medicine or elderly care service. In the majority (77.8%) of instances the isolate was attributed to a clinical infection rather than colonisation and the commonest clinical specimen to yield the organism was urine, which was positive in 57.8% of patients. Acquisition of the organism was categorised as nosocomial in 68.9% of patients; in this subgroup, the median duration of inpatient stay prior to recovery of the organism was 24 (range 3-240) days. Haemodialysis-dependence was the most common of the comorbidities evaluated. The mean number of antibiotics prescribed per patient in the 30 days prior to first isolation of the organism was 1.7 (range 0-4). Furthermore, the mean number of antibiotic-days exposure per patient during this period was 13.9 (range 0-48). The most frequently received class of antibiotic was beta-lactam/beta-lactamase inhibitor combinations. Of 35 infections, 26 (74.2%) were successfully treated. Overall 12 patients with infection died (34.3%); attributable mortality was presumed in seven (20%).

The epidemiology of peritonsillar abscess disease in Northern Ireland

1. To describe the epidemiology of peritonsillar abscess disease in Northern Ireland. 2. To describe the impact of the nature of microbiological sampling on culture results.

Trends in the epidemiology of Candida bloodstream infections in Northern Ireland between January 1984 and December 2000

Objective: To describe the epidemiology of Candida bloodstream infections (BSI) in Northern Ireland. Methods: Retrospective collation of data relating to all clinically significant BSI in a university teaching hospital, which had been recorded prospectively, between 1984 and 2000. Results: One hundred and forty five episodes of candidaemia occurred in 144 patients (of mean age 56.6 years). The contribution of Candida spp. towards all significant BSI increased from 2.00% to 2.5%. C. albicans was the most frequently isolated species, however, its incidence fell from 70% to 53% during the study period. The greatest increase in incidence was seen with C. glabrata which was the most common non-albicans species. Twenty-nine per cent of isolates occurred in patients from an intensive care unit and, surprisingly, a further 25.5% occurred in patients from a surgical service. Conclusion: There appears to be several subtle differences in the epidemiology of candidal BSI between Northern Ireland and other countries. © 2002 The British Infection Society.

Mycobacterium triplex pulmonary infection in an immunocompetent patient

We present the case of a 47-year-old immunocompetent patient with clinical evidence of pulmonary mycobacterial disease which was found to be due to Mycobacterium triplex. This novel organism is an uncommon, emerging, pathogen for which few reports of clinical infection exist in the medical literature. © 2002 The British Infection Society.

Evaluation of the VITEK 2 AST N-054 test card for the detection of extended-spectrum beta-lactamase production in Escherichia coli with CTX-M phenotypes

A new VITEK 2 antibiotic susceptibility testing (AST) card, AST N-054, was introduced for aerobic gram-negative bacilli in 2007 and has been widely adopted for routine use in the UK. We evaluated its performance for detecting extended-spectrum beta-lactamase (ESBL) production in Escherichia coli.

Trends in candidemia and antifungal susceptibility in a university hospital in Northern Ireland 2001-2006

Objectives: To describe the species distribution and antifungal susceptibility trends for documented episodes of candidemia at the Royal Hospitals, Belfast, 2001-2006. Methods: Laboratory-based retrospective observational study of all episodes of candidemia. Results: There were 151 episodes of candidemia. The species recovered were: 96 C. albicans; 26 C. glabrata; 18 C. parapsilosis; five C. tropicalis; four C. guilliermondii; one C. famata and one C. dubliniensis. We separated the data into two periods 2001-2003 and 2004-2006; contrary to the findings of other investigators, there was a notable trends toward increasing frequency of C. albicans and decreasing frequency of non-albicans species over time. Although the proportion of C. albicans, C. parapsilosis and C. tropicalis isolates susceptible to fluconazole was unchanged over time, a trend of decreased susceptibility of C. glabrata to fluconazole was noted over the six-year period. Overall, 73% and 7.7% of C. glabrata isolates had susceptible-dose-dependent and resistant phenotypes, respectively. The percentage of C. glabrata isolates susceptible to fluconazole (MIC

Catheter-related bloodstream infection in adult haematology patients:Catheter removal practice and outcome

The aim of the present study was to describe the practice of central venous catheter (CVC) removal and outcomes of catheter-related bloodstream infection (CR-BSI) in adult haematology patients. Patients were identified retrospectively according to diagnosis coding of inpatient episodes and evaluated when, on examination of medical records, there had been evidence of sepsis with strong clinical suspicion that the source was the CVC. Demographic and bacteriological data, as well as therapeutic measures and clinical outcomes, were recorded. One hundred and three patient episodes were evaluated. The most frequent type of CVC was the Hickman catheter and the most frequently isolated pathogen was coagulase-negative staphylococci. Twenty-five percent of episodes were managed with catheter removal. Treatment failure, defined as recurrence of infection within 90 days or mortality attributed to sepsis within 30 days, occurred significantly more frequently in the group managed without catheter removal (52.5% versus 4%, P

Substantial genetic divergence between morphologically indistinguishable populations of Fasciola suggests the possibility of cryptic speciation.

The liver flukes, Fasciola hepatica and Fasciola gigantica, are considered to be sister species and between them present a major threat worldwide to livestock production. In this study sequence data have been employed from informative regions of the nuclear and mitochondrial genomes of over 200 morphologically F. hepatica-like or F. gigantica-like flukes from Europe, sub-Saharan Africa and South Asia to assess genetic diversity. Evidence is presented for the existence of four well-separated clades: African gigantica-like flukes, Indian gigantica-like flukes, European hepatica-like flukes and African high-altitude hepatica-like flukes. Application of the Biological Species Concept to trematodes is problematic; however, the degree of separation between these groups was sufficient for them to be considered as distinct species using the four times rule for speciation.

Effect of a multifaceted intervention on adherence to hand hygiene among healthcare workers:A cluster-randomized trial

OBJECTIVES. Adherence to hand hygiene among healthcare workers (HCWs) is widely believed to be a key factor in reducing the spread of healthcare-associated infection. The objective of this study was to evaluate the impact of a multifaceted intervention to increase rates of adherence to hand hygiene among HCWs and to assess the effect on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) colonization. DESIGN. Cluster-randomized controlled trial. SETTING. Thirty hospital units in 3 tertiary care hospitals in Hamilton, Ontario, Canada. INTERVENTION. After a 3-month baseline period of data collection, 15 units were randomly assigned to the intervention arm (with performance feedback, small-group teaching seminars, and posters) and 15 units to usual practice. Hand hygiene was observed during randomly selected 15-minute periods on each unit, and the incidence of MRSA colonization was measured using weekly surveillance specimens from June 2007 through May 2008. RESULTS. We found that 3,812 (48.2%) of 7,901 opportunities for hand hygiene in the intervention group resulted in adherence, compared with 3,205 (42.6%) of 7,526 opportunities in the control group (P <.001; independent t test). There was no reduction in the incidence of hospital-acquired MRSA colonization in the intervention group. CONCLUSION. Among HCWs in Ontario tertiary care hospitals, the rate of adherence to hand hygiene had a statistically significant increase of 6% with a multifaceted intervention, but the incidence of MRSA colonization was not reduced.

RNA interference targeting cathepsin B of the carcinogenic liver fluke, Opisthorchis viverrini

Functional genomics have not been reported for Opisthorchis viverrini or the related fish-borne fluke, Clonorchis sinensis. Here we describe the introduction by square wave electroporation of Cy3-labeled small RNA into adult O. viverrini worms. Adult flukes were subjected to square wave electroporation employing a single pulse for 20 ms of 125V in the presence of 50 µg/ml of Cy3-siRNA. The parasites tolerated this manipulation and, at 24 and 48 h after electroporation, fluorescence from the Cy3-siRNA was evident throughout the parenchyma of the worms, with strong fluorescence evident in the guts and reproductive organs of the adult worms. Second, other worms were treated using the same electroporation settings with double stranded RNA targeting an endogenous papain-like cysteine protease, cathepsin B. This manipulation resulted in a significant reduction in specific mRNA levels encoding cathepsin B, and a significant reduction in cathepsin B activity against the diagnostic peptide, Z-Arg-Arg-AMC. This appears to be the first report of introduction of reporter genes into O. viverrini and the first report of experimental RNA interference (RNAi) in this fluke. The findings indicated the presence of an intact RNAi pathway in these parasites which, in turn, provides an opportunity to probe gene functions in this neglected tropical disease pathogen.

Zoonotic helminth infections with particular emphasis on fasciolosis and other trematodiases

Zoonotic infections are among the most common on earth and are responsible for >60 per cent of all human infectious diseases. Some of the most important and well-known human zoonoses are caused by worm or helminth parasites, including species of nematodes (trichinellosis), cestodes (cysticercosis, echinococcosis) and trematodes (schistosomiasis). However, along with social, epidemiological and environmental changes, together with improvements in our ability to diagnose helminth infections, several neglected parasite species are now fast-becoming recognized as important zoonotic diseases of humans, e.g. anasakiasis, several fish-borne trematodiasis and fasciolosis. In the present review, we discuss the current disease status of these primary helminth zoonotic infections with particular emphasis on their diagnosis and control. Advances in molecular biology, proteomics and the release of helminth genome-sequencing project data are revolutionizing parasitology research. The use of these powerful experimental approaches, and their potential benefits to helminth biology are also discussed in relation to the future control of helminth infections of animals and humans.

Cathepsin F cysteine protease of the human liver fluke, Opisthorchis viverrini

The liver fluke Opisthorchis viverrini is classified as a class I carcinogen due to the association between cholangiocarcinoma and chronic O. viverrini infection. During its feeding activity within the bile duct, the parasite secretes several cathepsin F cysteine proteases that may induce or contribute to the pathologies associated with hepatobiliary abnormalities.