CLOSTRIDIUM DIFFICILE

Clostridium Difficile

Clostridium Difficile

Introduction

Clostridium difficile is a gram positive bacterium. It is a motile, spore-forming bacillus and anaerobic that produces toxins A and B, which have been identified as the major virulence factors . It causes of antibiotic-associated diarrhoea (AAD) because it, with its multidrug resistance and can lead to pseudomembranous colitis, a severe infection of the colon. It may result in serious illness and even death. It colonizes in the gut flora of adults .

Nowadays, it is considered as a major opportunistic pathogen. C. difficile infection represents one of the most common hospital infections around the world . It is strictly anaerobic microorganisms. It able to grow at the expense of hydrogen and carbon dioxide as the sole energy source, hydrogen serving as the electron donor for CO2 reduction to acetate .

The metabolism of C. difficile is in large part adapted to life in the intestinal tract.  It produces enzymes that degrade nutrients abundant in the intestine. Carbohydrates are the preferred nutrient source, and C. difficile has the ability to metabolize a wide range of carbohydrates. The bacteria also have a relatively unique ability to utilize ethanolamine, an abundant phospholipid provided by the host's dietary intake, as a carbon and nitrogen source .

C. difficile has the enzyme that catalyzes the decarboxylation of p-hydroxyphenylacetate (a tyrosine degradation product) to p-crysol, a compound that stunts bacterial growth. C. difficile produces and tolerates high concentrations of p-crysol, giving it a competitive advantage over the normal bacterial flora in the intestine .

C. difficile has dependent on methane metabolism which is metabolized principally by the methanogens in the global carbon cycle. Methanogens produce methane as a metabolic by product. It can obtain energy for growth by converting a limited number of substrates to methane under anaerobic conditions. Only three types of methanogenic pathways are known: methanogenesis from H2/CO2 or formate [MD:M00347], methanol to methane [MD:M00356], and acetate to methane [MD:M00357]. Methanogens use 2-mercaptoethanesulfonate (CoM; coenzyme M) as the terminal methyl carrier in methanogenesis and have four enzymes for CoM biosynthesis [MD:M00358]. Coenzyme B-Coenzyme M heterodisulfide reductase (Hdr), requiring for the final reaction steps of methanogenic pathway, is divided into two types: cytoplasmic HdrABC in most methanogens and membrane-bound HdrED in Methanosarcina species. Figure1

Clostridium difficile is a Gram-positive, toxin-producing anaerobic bacterium belonging to the family Clostridiaceae of the Clostridiales. Though strictly oxygen-intolerant, C. difficile is able to produce aerotolerant endospores under unfavourable conditions that are capable of persisting in an open environment for years. C. difficile is a commensalist species typically housed in the colonic fecal flora of a fairly small subset of the child population, with the number of carriers decreasing as children age (Kelly and LaMont, 1998). When it exists in small numbers, this organism remains non-pathogenic. However, when it does manage to colonize and yield larger populations, its pathogenicity becomes the root cause of a variety of coloninfections.

Figure 1. This micrograph depicts Clostridium difficile bacteria from a stool sample culture.

  Infection by C. difficile arises in an opportunistic manner; normal microflora in the gut attributes to the body's defense against pathogenic domination and so, mass colonization ...