gyrA Mutations in Fluoroquinolone-resistant Clostridium difficile PCR-027

The development of underground infrastructure, environmental concerns, and economic trend is influencing society. Due to the increasingly critical nature of installations of utility systems especially in congested areas, the need for monitoring and control system has increased. The microtunneling system will therefore have to provide for possibility of minimized surface disruption. Suitable selection of Microtunneling Boring Machine (MTBM) is the most curial decision that manager must be done. Because once the trenchless excavation has started, it might be too late to make any changes in equipment without extra costs and delays. Therefore, the various factors and parameters are affecting the choice of machine. In this paper discusses a developed methodology based on Fuzzy Analytic Hierarchy Process (FAHP) in order to determine weights of the criteria and sub criteria and then ranking them. Within the proposed model, four criteria site, machinery, structural, labor force impact and 18 sub-criteria are specified. The linguistic level of comparisons produced by experts are tapped and constructed in a form of triangular fuzzy numbers in order to construct fuzzy pair wise comparison matrices. Therefore, FAHP uses the pair wise comparison matrices for determining the weights of the criteria and sub-criteria.El desarrollo de infraestructura subterránea, con preocupaciones ambientales y tendencias económicas, está influyendo a la sociedad. Debido a la naturaleza crecientemente crítica de las instalaciones de sistemas utilitarios, especialmente en áreas congestionadas, ha aumentado la necesidad de sistemas de monitoreo y control. Por lo tanto el sistema de microtunelación ayudará a minimizar la superficie perturbada. La selección adecuada de Máquinas Taladradoras de Microtúnel (MTBM, por sus siglas en inglés) es la decisión más juiciosa que puede hacerse, puesto que una vez que la excavación sin zanjas ha iniciado, podría ser muy tarde para hacer cambios en el equipo sin un costo ni atrasos adicionales. Luego, los diversos factores y parámetros afectan la escogencia de la máquina. En este artículo se discute una metodología desarrollada, que se basa en el Proceso Jerárquico Analítico Difuso (FACH) para determinar pesos de los criterios y subcriterios, y luego ordenarlos. En el modelo propuesto se especifican cuatro criterios de sitio, maquinaria, estructura, impacto de la fuerza laboral y 18 subcriterios. Los niveles lingüísticos de comparaciones producidos por expertos se construyen en forma de números difusos triangulares para construir matrices de comparación difusa por parejas. Por lo tanto el FAHP usa las matrices de comparación por parejas para determinar los pesos de los criterios y subcriterios

Isolation and Characterization of toxin A-negative, toxin B-positive Clostridium difficile in Dublin, Ireland

Clostridium difficile is a major cause of infectious diarrhoea in hospitalised patients. Most pathogenic C. difficile strains produce two toxins, A and B; however, clinically relevant toxin A-negative, toxin Bpositive (A– B+ ) strains of C. difficile that cause diarrhoea and colitis in humans have been isolated worldwide. The aims of this study were to isolate and characterise A– B+ strains from two university hospitals in Dublin, Ireland. Samples positive for C. difficile were identified daily by review of ELISA results and were cultured on selective media. Following culture, toxin-specific immunoassays, IMR-90 cytotoxicity assays and PCR were used to analyse consecutive C. difficile isolates from 93 patients. Using a toxin A-specific ELISA, 52 samples produced detectable toxin. All isolates were positive using a toxin A ⁄ B ELISA. Similarly, all isolates were positive with the cytoxicity assay, although variant cytopathic effects were observed in 41 cases. PCR amplification of the toxin A and toxin B genes revealed that 41 of the previous A– B+ strains had a c. 1.7-kb deletion in the 3¢-end of the tcdA gene. Restriction enzyme analysis of these amplicons revealed the loss of polymorphic restriction sites. These 41 A– B+ isolates were designated toxinotype VIII by comparison with C. difficile strain 1470. PCR ribotyping revealed that all A– B+ isolates belonged to PCR-ribotype 017. A– B+ C. difficile isolates accounted for 44% of the isolates examined in this study, and appeared to be isolated more frequently in Dublin, Ireland, than reported rates for other countries

PCR-ribotype distribution of Clostridium difficile in Irish pigs

Clostridium difficile is an important enteric pathogen in humans causing infections in the healthcare environment and the community. Carriage of C. difficile and C. difficile-related enterocolitis has been reported in piglets worldwide. The aim of this study was to investigate the rates of C. difficile isolation from pigs in Ireland. Faecal samples from piglet litters and sows were collected from six farms in 2015. The sows were non-diarrhoeal at the time of sampling. The diarrhoeal status of the piglets was unknown. C. difficile was isolated from 34/44 (77%) of piglet litter samples and from 33/156 (21%) of sow samples. The isolation rate in sows varied from 3 to 39% and in piglet litters from 72 to 86% depending on farm location. Toxin A and toxin B were present in 99% (66/67) of isolates; and binary toxin in 85% (57/67). Only PCR-ribotypes 078 (88%) and 193 (12%) were identified in piglets. Seven PCR-ribotypes were detected in sow C. difficile isolates: PCR-ribotypes 078 (67%), 050 (12%), 014/020 (6%), 015 (6%), 029 (3%), 035 (3%) and 193 (3%). This study shows that toxigenic C. difficile strains such as PCR-ribotype 078 can be commonly isolated from pigs at different geographical locations in Ireland. Since PCR-ribotype 078 is frequently found in humans in Ireland, this highlights the potential for interspecies transmission

Susceptibility of hamsters to clostridium difficile isolates of differing toxinotype

Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD), which caused ~21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative), M68 (toxinotype VIII) and BI-7 (toxinotype III). The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c.) with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT) are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial and toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression