I am going to offer my constructive criticism but realize that I don't know the exact context for which these were made. Overall I think the presentations are very good and I can honestly say I learned some things from what I read... but with how long they are I had a hard time focusing on all of the slides.
A) Exceptionally long. 35 slides has been shown in laboratory tests to drive people insane. (Just kidding but it is kind of long). Typically when I make a trainings / powerpoints I break them up into sections/files that are about one subject. Also mine are for floor workers and temps so they need to be quick, to the point, and not nearly as detailed as all of this. I don't know if you had a 2 hour slot you were filling with this presentation or whatnot just a suggestion based on how I felt when I reviewed it... but maybe your presentation is spellbinding much more than mine
B) I agree with Zeeshan about your organization. You need a good logical flow to your presentations otherwise you are going to lose parts of your audience, especially ones who don't know the topic as in depth as you. This presentation seems to jump all over the place. Build up to the specifics of the body parts after describing the different pathogens and what effect they have. It's proven that people remember the last things they hear/see so if you put all of that information and then relate it to what they have on them I believe it would have a better impact.
C) Technique. The first time you mention Staphylococci on the first slide that's all you have but on the second slide you actually put Staphylococcus Aureus. Your presentation would look better if you put that level of detail on the first time something is mentioned rather than the 2nd time it's presented.
D) Slide 25: Great slide. To think all that we do that only tries to prevent 5000 deaths however when was this data till? Was it 1996 to 1997 or 2006? Was it 5000 deaths in 1 year, 5 years, 10 years? This will add more relevance to the data that your displaying. If you use this one slide for 5 years those numbers should have changed and it will skew the information your trying to present.
E) Slide 26: Typo "Lack of Reporting Requirements" - I have typos all over my presentations don't feel bad... I hate when I typo with an actual real word because if spell check doesn't find it 1/2 the time my proofreaders miss it.
F) Slide 27: Typo "4 staff members suffering..."
H) I agree on the background if you can make that more opaque that would be a great background picture.
2) Presentation 2:
A) Very good presentation however it's still a little long in my personal opinion.
B) Good logical flow.
C) Still a dark background for the words.
Overall I think they are very good. You have a very in depth knowledge of the subject matter and I'm sure you convey it well. I found them very informative. I hope some of this helps.