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Laboratory diagnosis of Clostridium difficile
JANDOVÁ, Romana
Clostridium difficile toxin with production is the most common cause of nosocomial enteric infections. It causes inflammatory bowel disease called Clostridium difficile infection (CDI) of varying severity - from trivial diarrhea to life-threatening conditions such as paralytic ileus and toxic megacolon. C.difficile still escapes the attention of the general public and is in the background of other bacteria, such as MRSA. Clostridium difficile is a strictly anaerobic bacterium. It is a gram-positive rod forming an oval subterminal spores. C. difficile can produce two types of toxins - and toxin A (enterotoxin) and toxin B (a cytotoxin). Due to the toxin causes damage of the intestinal epithelium and deeper layers of the bowel wall. Into inflammatory ulceration that cover of the pseudomembrane. Some strains produce more binary toxin, whose exact function is not underwood yet. It is assumed that potentiates the effect of toxins A and B to increase their concentration. To demonstrate the CDI must remove the stool sample into a sterile tube. In the bacteriology workplace in Czech Budweis Hospital is being made direct conclusiveness of antigen and toxin by immuncgromatography method. It is a membrane-enzyme immunoanalysis for the detection of antigen - glutamate dehydrogenase (GDH) and toxin A / B. Negative result excludes GDH with high reliability clostridial infection. For confirmed CDI is considered proof toxigenic strain of C. difficile. This is evident from the result of either immunochromatography which is demonstrated both the antigen and the toxin, or identity of the gene for toxin B by PCR. If you find out in direct detection only positive antigen, the sample is sent for PCR testing to the Laboratory of Molecular Biology and Genetics. Regardless of the outcome of the immunochromatography, the microscopic specimen stained by Gram are being produce from reces. In the case of proven C. difficile toxin is carried anaerobic culture test that takes two days. For identification of accrued bacteria is used latex agglutination. This is a method in which IgG antibodies bound to latex particles specifically bind to the antigens of the cell wall. To identify the bacteria can be also used the VITEK - MS machine that uses a laser ionization method in the presence of the matrix, followed by mass spectrometry. In case of a positive culture findings Clostridium difficile is being from grown culture set sensitivity to antibiotics by E-test and disk diffusion methods For the year 2011 the Department of Bacteriology examined 291 samples of feces. 13,4 % of these samples had positive antigen and toxin in an imunochromatographyc examination; 15,1 % had a positive antigen and negative toxin and 71,5 % were negative. 74 samples was positive in C. difficile toxin. These samples were subsequently conducted to culture examination - 62,2 % were positive. Most positive samples were sent from the infectious department. It has been examined 53,6 % of women and 46.4 % of mens. Percentage of toxigenic strains of both sexes were virtually identical - 25 %. All strains were susceptible to vancomycin and only one strain was resistant to metronidazole.
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