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Lecture 14

SCI1101 Lecture 14: Haemophilus Influenza- Lecture 5

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Science (General)
Don Dawson

Haemophilus Influenzae: Gram-negative bacilli - We have a vaccine so we do not see many cases with this - No so common in canada or the us Enterobacter spp. (Cronobacter) - Opprotunistic pathogen - Found in cattle cow or even milk. - Mostly in premature babies - Staff in a ICU found in dry infant formula powder once you put liquid in it that’s when the bacteria can spread and multiply Helicobacter Pylori: - It is very famous and it is a cause of gastric ulcers - They decided that there should be a policy that they will not use humans this now can not occur because of this - Ulcers now is coupled with antibiotics Bordetella Pertussis - Whooping Cough - 4 Virulent factors: - Can be vaccinated - Has an interesting story: there was an earlier version of this vaccine that was used worldwide. - There was a low risk and in some cases some will react very seriously. - Some countries stopped using the vaccine. Legionella pneumophila (spends a lot of time on this) - New bacteria discovered recently and causes Legionnaries Disease - Common in elderly. - What is the cause? It was difficult to find and a few deaths were reported. They tried all the known media and tried to find something that they were able to culture. They were successful in landing on one media that they isolated a colony in a media. That was able to support growth of a small colony now called Legionella Pneumophila. There was still the question though as to where this bacteria came from and fortunately since they were found in this hotel. It was found on the roof top of the hotel and since the air conditioning was on and it was giving off a lot of condensation and there were pulls of water. It is only found in a very wet and aqueous environment. - The cases were all found in this hotel. Too see where the source of the new pathogen. It was found on the roof top of the hotel. - The air conditioning was there the whole time. - There was pulls of water. Legionella pneumophila . - These legionella pneumophila got into the air conditions and these bacteria were getting into the ventilation of the hotel. - Hospitals, senior residences. - This organism could have been worse bc it is an air borne pathogen and usually you get hundreds and thousands. - It does not pass from person to person. If the bacteria is living in the environment if someone breaths it in in the environment then they can get it. As it multiplies in the person and they cough and that second person would not get the symptoms. - You cannot get Legionnaires disease because it has to come from the environmental source. - It illustrates that the only reason we know about a pathogen is that it has caused diseases in a lab. It took so long to discover so this just emphasizes that there are so many more of them out there Mycobacteria When you isolate a bacteria it will not stay either purple or pink. Causative agents of tuberculosis and leprosy (diseasethatprimarilyaffectstheskinandthenervesoutsidethebrainandspinal cord,PNS.Itmayalsostriketheeyesandthethintissueliningtheinsideofthenose.) - These are important pathogens. - They all share common things : - 1.) Cause TB and 2.) Leprosy - The major key characteristics is that they have a high concentration of a wax material in their cell wall. We can’t do gram-staining. - The bacteria is very resistant to certain environments. - There are reffered to as acid-fast bacteria - Ziehl-Neelsen Stain; you have to get around the wax material - 1.) Carbol Fuchin for five minutes - 2.) Apply heat to the stain remove the Bunsen burner and let it cool off. - We go through so much trouble is it grows slowly. Mycobacterium Tuberculosis: - They multiply every 20 minutes. - Compare it to bacterium tuberculosis it is way too long to find a staining technique. - It is a obligate aerobe and causes a lung infection. They require oxygen and they are intracellular and they get inside host cells - 4-6 weeks till you get any colonies - TB used to be a huge problem when it comes to infectious diseases - Primary Tuberculosis: 1.) Breathing in aerosol 2.) Gets into lungs and multiplies 3.) It can escape and internalize itself as a tracheal cell. (Human host cells) 4.) It can be digested by macrophages and forms these complexes (primary complex) 5.) They will stay in the lungs. About 6 weeks the day you get exposed there is no symptoms They can stay hidden in the lungs for many years. In some limited cases under some kind of conditions some of them can get reactivated and this is where you can get the typical TB symptoms. If not treated it can be reall deadly Post-primary tuberculosis only 5 % will develop these symptoms. This is an example of a chronic infection Immunity in Tuberculosis: - Best way to screen is by doing the Mantoux Test - Specific protein by doing intradermal - Redness to the reaction to the protein. - They are not that specific and they can get subjective. If you see a clear zone a little bump . - Anything from five to nine and anything less than 4 is negative - How you major diameter can be subjective. - A positive infection does not mean that they . They may have been infected before . They
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