Listeria Innocculosis

AIM – The aim of the experiment is to determine the relative effectiveness of several anti-microbial substances on developing pathogens. (E. coli)

The aim of this experiment was to observe the effect different concentrations of Dettol had on the growth of S. albus. The highest concentration of Dettol (100% - D) was predicted to be the most effective solution to kill and stop the growth of this particular bacteria. This can be justified as S. albus is gram-positive; easier bacteria to kill, developing resistance slower than a gram-negative. Therefore, the highest concentration of antibiotic should be – and was – the most successful in changing the pH levels, and killing S. albus. Through discussion and analysis of the results collected through the experiment, it can be concluded that there is higher chance of killing and the growth of this particular bacteria if 100% Dettol is used.

What would explain the phenomenon of a minute growth near a disc that had a clear zone of inhibition is that the agent is bacteriostatic because it is it is inhibiting the growth of the bacteria versus a bactericidal agent which just kills

9. After the 48 hour time period the inhibition of the Escherichia coli bacteria around the disinfectant disks was measured. A ruler was used to measure the clearing from the edge of the disk to the perimeter of the clearing. Irregularities in the clearing were not included in the area of clearing.

37 The purpose of this latest amendment was to ultimately improve the oversight and compliance activities of R.T.E foods with respect to their potential to support the growth of Listeria. For example, it is now a requirement that environmental monitoring programs are incorporated in to all plants and are used in the production of R.T.E food products. 38 Furthermore, the definition of R.T.E foods was updated and expanded upon with regards to which foods display the potential to grow of L. monocytogenes and a more detailed list of foods prone to contamination. 39 This policy revision also focused aimed to provide an even greater focus to at protecting the high-risk members of society, specifically the infants, pregnant women and the elderly. 40 This aspect of the 2011 policy decision was greatly influenced by the European cases of listeriosis regarding the decision to utilize more efficient risk communication programs intended to protect these vulnerable groups, specifically the aging members of society. 41 The majority of European cases have been attributed to elderly population, as they are exceedingly prone to becoming ill. Therefore, this provided even more need to center the policy on these at risk groups.

The Kirby-Bauer disc diffusion method was used to examine sensitivity of antimicrobial agents, it fast and simple way to find an antibiotic to use for a treatment of some type of infection. This method uses a plate that has been cover with the testing bacteria and small disc covered in the antibiotic to see if the bacteria is able to around the disc, it will make an even circle around the disc which is the zone of inhibition. This zone of inhibition diameter can be measured and compared to the interpretation chart to find the antibiotic sensitivity or resistance. When the zone of inhibition is very small or nonexistent this shows that bacteria is resistant to the antibiotic and will not work against this bacterial infection. If the zone is

Management of Listerosis in pregnant women first begins with avoidance of contaminated or high risk foods. Foods that are considered high risk includes, hot dogs, lunch meats, cold cuts, refrigerated seafood and meat spreads, unpasteurized dairy products, and unwashed produce. In M.L.’s case since she’s symptomatic and febrile, she will need testing via blood cultures and begin IV therapy with IV ampicillin. If blood cultures are negative, the physician has the choice whether to continue with IV treatment. In the case that the blood cultures are positive for listerosis, M.L. will receive 6g of ampicillin daily for two weeks. In case of an allergy to ampicillin, Bactrim may be given as a substitute. Another way of confirming a diagnosis of listerosis

SP-D had shown the growth inhibition of E coli, Legionella pneumonia, Enterobacter aerogenes and Klebsiella pneumonia by increasing the cell membrane permeability (Wu et al., 2003) but not in the case of mycobacteria (Ariki, 2011). We performed experiment to find out either recombinant conglutinin increased the cell membrane permeability of the M. bovis BCG and as a result growth inhibited which is shown in figure 4.3. Heat-treated M. bovis BCG used as a positive control. While heat-treated M. bovis BCG were stained with propidium iodide, they absorb PI stained due to increased cell membrane permeability achieved with heating. It has been confirmed that M. bovis BCG coated with conglutinin does not kill mycobacteria by increasing cell membrane permeability as those bacteria does not shown the propidium iodide absorbance. From this experiment we observed that the direct effect of conglutinin is bacteriostatic rather then bactericidal, as no bacterial cell lysis

In the experiment “Antimicrobic Sensitivity Testing: The Kirby-Bauer Method” students used six different antimicrobics to identify which antimicrobics were effective in killing four different organisms. The four different organisms that students used in this experiment were: E. coli, Proteus Vulgaris, P. aeruginosa, and S. aureus. And the six antimicrobics that students used in this experiment were: Amoxicillin, Cefoxitin, Chloramphenicol, Doxycycline, Rifampin, Vancomycin. Each organism was swabbed in a different plate of nutrients, and the six antimicrobics were placed in the plate, too. After swabbing the organism and placing the antimicrobics, the plates were incubated for forty-eight hours.

The purpose of this Literature review is to gain a broader insight into the food borne pathogen known as Listeria and its traits .In This review I will discuss in detail the different types of Listeria Species which can be isolated from various types of food samples and determining their overall antibiotic resistance, the illness associated with each and the incidences and outbreaks worldwide. I will then compare my overall findings, due to the word count I will not be discussing the Biochemical tests in this review. Over the last number of years there has been a wide variety of research and experiments carried out on this food borne opportunistic Pathogen. The title of this Literature review has been researched by

Listeria is the name of a bacteria found in soil and water and some animals, including poultry and cattle. It can be present in raw milk and foods made from raw milk. It is also found in marine environments and is often associated with fish and seafood products. Animals such as sheep, goats and cattle are

Listeria Monovytogenes is a soil opptunistic bacterium that at same time is a food borne pathogen. Though its existence in nature can be as high as 20% in soil-plant sample, the infection occurs in healthy population is rare. However, to population that have immature or compromised immune systems, it is a dangerous pathogen; its infection has a mortality rate as high as 30%. The first record of L. Monovytogenes discovery was in 1926, when Department of Pathology of the University of Cambridge routinely autopsies their laboratory animals that died during breeding, they found six rabbits that suffered sudden death have similar lesions without exposure to evident toxic or infection (). Two months later, they obtained a pure culture of gram-positive bacilli that is associated with observed disease. It was first named by the experimenters as bacterium monocytogenes and later it was categorized in to Listeria genus. After its discovery, L. Monovytogenes was found associated with neonatal sepsis and meningitis by a coincidence. In 1950, East German scientist Potel and his coworkers discovered several case of septicemia in newborn baby that have common characteristics of focal necrosis while in West Germany, scientist Seelinger found that adult suffer listeria septicemia also have similar focal necrosis(), and later, their collaborate work confirmed that L. monocytogenes is a significant pathogen in perinatal infections. However, it was not until 1981 that people

Listeriosis is a life threatening infection which is caused by eating food that has been contaminated with the bacteria “Listeria monocytogenes”. This bacterium is most commonly found in dirt, water, and plants. The people that are most likely to contract this infection are high risk populations; such as elderly people, pregnant women, young children, and people with compromised immune systems. It is estimated that 1,600 people become infected with listeriosis every year, and about 260 people die from the infection, which means 1 in 5 infected can die. A few of the symptoms are fever, muscle aches, nausea, and sometimes death.

Listeriosis is a serious infection that result from food contamination with the bacterium L. monocyogenes. It I known to be in fact, “one of the most deadly bacterial infections currently known- with a mean mortality rate in humans of 20 to 30% or higher despite early antibiotic treatment” 11. Besides the transmission of foodborne, it can also be transmitted from mother to fetus or human-to human physical interaction. A mother can consume contaminated food or liquid such as milk during pregnancy and be able to transmit to the fetus through the maternal blood stream or from a colonized genital tract5 (See Figure 3). This can cause serious factors leading to premature delivery, miscarriage, or other serious health issues for the newborn.5

The main objective of this experiment is to investigate the effect of different types of antibiotics on bacteria Bacillus subtilis and Escherichia coli. Some of the main methods used in this experiment