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BIOL 2320_Microbiology for Non-Science Majors - 09_27_22_Lecture
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00:27 Okay folks, um let's go ahead get started. Uh Okay, I
00:38 , put my usual announcement slide in . But so of course exam friday
00:48 this week. Uh if you haven't up, please do sign up on
00:55 website if you have questions or so I'm available. If not,
01:00 can't make regular alpha sours, just me, figure something out. So
01:06 , if you have any last minute , what have you, everything uh
01:12 and thursday is not on the so we're through with what's on the
01:17 . We finished that last thursday. uh so we start seven and we
01:22 much will finish seven today I Uh then on to chapter eight.
01:28 again this week's stuff, we're doing here is not on the exam.
01:32 um, so again the exam is . So make sure you look at
01:40 real exam review sheet. Okay. the blackboard, the blackboard, quit
01:48 quiz answer key will be available first actually at midnight tonight if you
01:54 if you want to be up late when it's open when it opens,
01:59 anyway, do look look through that if you have questions relating to
02:04 let me know. Um So like I said, I'm available,
02:10 you need, if you have any , what have you um if you
02:13 , that's fine, but just make specific question is not really broad
02:18 I have to write a book. , so um so again today's stuff
02:24 material, not an example. We're with unit one basically. Okay.
02:29 today's material is an extension of really growth because of course we went through
02:37 whole growth cycle stages of growth. batch growth. So we have a
02:43 of cells right over time. We have that typical growth response.
02:52 ? Um Black log log stationary And so we're actually what we're doing
02:56 focusing on this part here. What's on out here and basically forcing death
03:05 occur. Right, adding antiseptic or or radiation or what have you?
03:12 , so we're actually actively killing them trying to make that part of the
03:16 of course go as fast as Okay um and of course we're also
03:22 uh of course when you do a of treatment whether your radiation or chemicals
03:28 have you you even though you're targeting you of course are reducing numbers of
03:35 . Okay. Obviously. But you of interesting though of course is targeting
03:41 because that's that's what causes humans the problems. Right. So sorry about
03:48 . The so anyway so that's what focusing on today. And so there's
03:52 be some terms you're gonna you know gonna have a question here. Right
03:56 a second. Uh so just briefly actions into microbial agents, physical methods
04:05 control. So things like temperature pressure ways to control microbial growth that way
04:13 which you're familiar with? Of course ? Antiseptics. And then you know
04:19 those things work and why? Why would use some types of killing mechanisms
04:26 some you don't. Okay, so , so let's start off. So
04:30 you know that my favorite thing, of my things is the misuse of
04:36 word. Okay, that one. um so we had a question relating
04:44 before. I think back in Chapter . So let's try this one
04:48 Okay, so sterilization equals. Mhm. Remember what sterilization is?
05:13 not talking sterilization in the context of have Children. Okay, this is
05:20 this is the other the other Okay. Alright. I'm gonna set
05:40 countdown from five 32. Okay, of you are correct. Okay.
05:54 above sterilization is is to find out next slide. Is this their removal
06:05 destruction of all living microbes? You the area you sterilized or the material
06:11 ? It is zero. Nothing is there. Okay. Absolutely devoid of
06:18 spores, viruses. What happened? , nothing is in there.
06:24 Everything else here will reduce numbers. , obviously right, they will all
06:30 the levels of microbes. Okay, they don't bring it down to
06:35 OK. Um and there's different sterilization are typically will do that.
06:41 but not everything can be autoclave. . Um There are certain chemical agents
06:46 can do it. Um uh So look at some of those things.
06:51 , so uh this infection and sepsis and sanitation. Okay, so I
06:59 we're pretty much aware of this infection sepsis is right. So they both
07:04 about reducing pathogen numbers is just, the surface? You are using inanimate
07:12 , tabletop wall bench top. Or is it a skin?
07:19 Is a living tissue? So, so for that reason and disinfectants can
07:25 much more concentrated. Much have much harsher type chemicals. Okay, I
07:32 bleach. Okay, uh sepsis is to be have to be more gentle
07:36 the skin. Right? But you still be effective in certain reducing microbial
07:41 . Okay. Um uh the german more mechanical action when you wash your
07:47 . You're basically the german, Because you also have this going
07:51 right, That mechanical action also um in kind of reducing microbial levels.
07:58 , So a combination of those Okay, sanitation is more sanitary
08:05 Okay, so if you've ever worked a in a restaurant, right,
08:10 a server or you worked in the itself. Um then you're probably aware
08:16 these things um unless your restaurant was the restaurant report on friday and then
08:21 probably weren't. Okay, so, so what that is, is doing
08:28 in a way to minimize, you , in a restaurant setting, of
08:32 , minimizing foodborne contamination. Right? having a foodborne outbreaks to do bad
08:39 . Right? So wearing a hair wearing gloves, right? Keeping the
08:44 clean where you prepare food, the clean. The soda fountains can get
08:50 gunky and stuff with that sugary syrup in there. And so making sure
08:53 clean. Um These are all potential where you can introduce uh foodborne
09:00 Of course restaurant doesn't want that. . These are all hygienic practices.
09:04 so so there whereas um and sepsis are specifically targeting pathogens and sanitation is
09:13 more overall kind of a thing that you do and reduce all levels.
09:18 of course pathogen levels as well. So what numbers you have to get
09:25 to? That's kind of up to local health department. Okay. They
09:30 codes and things for for these the you have to do and and the
09:36 you should be at. These kind things. So that's your county or
09:42 health department. Um So any questions these terms. Alright, so obviously
09:51 of you, most of you going health care and acceptance and disinfection in
09:56 Germany will be what you'll be familiar sterilization. Well you have to sterilize
10:02 sterilize surgical instruments. So you use that um prepackaged things, You would
10:10 catheters and things like that will be sterilized and those things are typically I
10:15 radiation is how they sterilize those The manufacturers do that at least.
10:21 But anyway, so this is just example of, I'm sure we've all
10:25 this on your favorite cleaner. Whether Lysol disinfectant rather lifestyle. What have
10:31 ? Uh they all have a number the front kills 99.9 or 99.99.
10:36 have you? Right. They always some value like that. Uh They'll
10:41 list um a different types of viruses bacteria that are medically important.
10:49 Right all manufacturers do this. They'll a list and generally it's fairly consistent
10:55 they all test. Okay so here see avian flu virus, this is
10:59 somewhat dated. I'm sure now the all have covid on it I would
11:04 . Um So different types of viral . Salmonella of course. Foodborne
11:10 E coli klebsiella, respiratory asian and on. Right so there's the
11:16 Right? That's the chipotle E coli um responsible for various food foodborne
11:24 But anyway so typical for any kind disinfectant. Okay um and it has
11:30 other things on here. Uh This hundreds of services in your home.
11:34 that's kind of a marketing thing But anyway you can see this for
11:40 . So sanitize the soft surfaces. it as a as a disinfectant is
11:47 it's more of a disinfectant on hard . Right? Because you can really
11:51 soak it well and rub it in well the soft surface like maybe a
11:55 or something is what I'm guessing out that you could spray it lightly And
11:59 can have some a little bit of , reducing overall numbers effect.
12:04 But that's not really the application for thing, an application for these of
12:08 is countertop toilet bowls, things like . Right. Anyway, so uh
12:14 kind of let's go back to this here, 99.9% killed. Okay.
12:20 if we do that, this is to a parameter that's used commonly used
12:26 measure death. Death of microbes by method. Okay, here, we're
12:32 looking at disinfection. Ok, by , this Lysol stuff. Okay.
12:37 uh so in terms of numbers we're talking about Big numbers. Of
12:41 . So here's a million cells. ? And so if he killed
12:45 you know, basically getting rid of . That's a lot. Right.
12:52 it's not everything right, because um still gonna have viable cells left.
12:58 . 10,000 viable cells. So we've down 10 to 6 to 10 to
13:02 fourth. Alright, that's two Okay. And logs of death is
13:07 have a lot of manufacturers measure Right? Measure their whatever their product
13:13 , and it's an antimicrobial agent. how many logs of death do we
13:17 ? That's kind of the parameter they to test it. And so of
13:22 it's getting lots of logs in a time period, that's optimal.
13:27 and so if we go from that million to 99.9. Which is what
13:33 claims it can do. Well then are going down 2000 bible cells.
13:38 three logs of death if we started this number. Right? These are
13:43 done. Um We have something like pretty good. Like a template typically
13:48 a two by two template square template is of course open in the middle
13:53 they put on the surface and they will swab to see what's actually
13:59 right? And then take the same area and then spray it with their
14:03 or apply whatever the chemical is. it sit there, follow the instructions
14:08 then tested again to see how many cells are there. And then you
14:12 up with this is this is the of death were getting. So that's
14:16 uncommon to do it that way. there's a bazillion ways to do to
14:21 these things. This is probably one the more popular science fair things kids
14:27 like in junior high and whatnot or younger is um I have some chemicals
14:33 the house and how can they be . I saw one that was
14:37 They went to the spice rack and up different spices and use that as
14:42 as the agent to reduce from a numbers. And so so very
14:47 There's lots of visual things. You just do. You have to always
14:50 numbers. You can get a visual see if there's an effect going on
14:53 we'll see a couple of these Um So okay so terminology it's a
15:00 static bacteria seidel and bacterial link terms used to assess how an agent is
15:09 on is having its effect. And so um again we're trying to
15:17 a negative rate very fast killing right . Okay. So but bacterial static
15:25 from the other two in that it kill it inhibits growth. Okay So
15:33 this and so the graphic we're looking right here is two things right?
15:39 have two lines. One is a line. Okay. And that's basically
15:44 taking samples. We're gonna take samples we're going to measure the total number
15:49 living cells in the flask. And um at the arrow. Right
15:56 arrow, that's where you see the . That's when the treatment was given
16:03 the culture. Okay. And so see you know what's the effect after
16:08 . Okay. And so again we the solid line which is viable
16:13 How many living cells per per volume in that culture. Okay. Um
16:21 there's a way you can do All right. The dash line is
16:26 what you're seeing under the microscope to the samples over time. You look
16:31 the microscope looking at the cells Or the cell numbers visually. Cell
16:36 increasing over time or what are they ? Okay. So of course prior
16:41 adding anything to it. The culture happily growing along. Alright so both
16:45 are going up. Okay then you the agent and all of a sudden
16:49 flattens out. Okay, so the to bacterial static effect is that the
16:57 viable cells count is not dropping It's raining steady. Okay. So
17:05 basically means you're not actively killing cells kind of inhibiting the roof. You're
17:08 able to grow anymore. Okay, the the bacterial seidel, bacterial
17:16 both are killing agents. Right? have that same effect. Okay.
17:21 so we see that in both. , Because the solid line, the
17:26 of living cells in that liquid have down following addition here with the arrows
17:34 Okay, so solid line solid line are going down. So living cells
17:41 of those are going down. That's the key parameter. Okay. And
17:46 basically the cells are no longer They're dying as prolonged exposure to the
17:54 . So, I think that's easy to understand now. It may be
17:57 of the oddball here is the dash . Okay, so remember that's what's
18:03 on under the looking at with your eyeballs under the microscope. Right,
18:08 what are the cells doing over Okay, so we've got in bacterial
18:14 It looks very much like bacterial static that respect, in terms of what
18:19 seeing under the microscope. Right? flat. Okay. Whereas bacterial lyric
18:23 going down. Okay, So what's on there? Well, it just
18:29 the type of killing going on, ? You can looking under the
18:36 Right. So wrote a right And Right here is where the arrow
18:41 Right, So, we're taking Post edition. Right? So post
18:45 of Chemical Agent, we see there's number of cells are remaining the
18:50 Right? So, this could be . Whether it's bacterial static or bacterial
18:55 . All right, Because you can without blowing up the cell. That's
19:01 what it is. You don't have you can kill the cells without blowing
19:05 up. Right? So, they're still be intact and you'll see them
19:08 every time point following exposure. So, agents like these can get
19:14 the cell. They can interfere with synthesis that would cause the cell to
19:19 , but it wouldn't be something that necessarily cause it to lice.
19:23 But you can have agents that are logic that can maybe do something like
19:31 the membranes, Right. Agents that dissolve membranes that certainly will pull the
19:37 apart and cause it to lice. , so, that would be a
19:40 lyric agent. So, you can that after the addition you have cells
19:45 have fewer fewer and there's only Okay, so, that's classic bacterial
19:50 agent. Okay, um from the of you know, you're killing whether
19:58 bacterial seidel materialistic, you're killing So, what's the concern?
20:04 well, a bacteriological agent. If was something if it were an
20:12 Okay, Might that have an impact it were bacterial lyric versus bacterial
20:18 Had to think back to what's the that gram negatives have that? Grand
20:23 don't? Well the the begins with nope en en endo toxin. No
20:39 effect right? Almost got them. And the toxin effect is um that
20:47 be problematic. So for a gram infection. Okay and you had a
20:52 lyric agent antibiotic? Well then we that. I think I had that
20:57 during class that scenario where the patient was given that and so it was
21:03 gram negative right? The gram negative up. Right? And so in
21:06 toxins being released. Okay and so have to come in with this other
21:11 that would then bind up the endo . But anyway that's literally just came
21:16 me as I was looking at this . But you know we're talking about
21:20 disinfectant that you're putting on a bench doesn't matter. You know how you're
21:25 him? As long as it goes . Okay um Is any question about
21:34 ? Alright so let's see here. so that that is log arrhythmic.
21:41 so you're not gonna get a profile it's everybody dying at once.
21:48 That will rarely happen if ever Okay the population of microbes um especially if
21:59 different species you don't know what you're the surface for example there's gonna be
22:03 there you don't know won't know what is necessarily in terms of genius and
22:08 . Okay. So certainly in that they're gonna be even if it's just
22:13 population of something, right? There's to be very slight variations from cell
22:17 cell, Right? Um There could be affected to be affected by
22:22 What it was really crowded with it might have some more on the
22:27 that are more susceptible than those down the in the in the middle or
22:30 bottom. Right? So that two create variations and how they're affected with
22:36 agent. So the point is killing always at some kind of a
22:40 Okay, so accumulation of damage Okay. Get enough hits.
22:46 So the chemical comes in and attacks a little bit of the membrane attacks
22:51 the proteins. Then you get enough damage in the cell dies and that's
22:54 to happen from cell to cell is different. Okay. So it's gonna
22:59 at some rate it could be very . Okay. But the point is
23:03 that some right? Don't expect it be all at once. Okay.
23:09 so the so we talked in the example was about logs of death.
23:16 . So that's where the value fits . Right? So the value is
23:20 one log one log of death how um to get there. So we
23:27 it D value. So this data for a heating 200 degrees.
23:32 Okay. I don't know what the is but um but you're gonna get
23:37 profile like this right? It's always be if you're typically going to be
23:41 kind of downward negative slope, Because we're killing cells. So it's
23:47 . How fast are we doing And so what you just look for
23:50 two points That are one log Right? 10-4 then the fifth.
23:57 ? You just extrapolate because you know that's going to be uh the
24:02 Value right? Time to kill Right so approximately a minute.
24:08 It's you know depending on the treatment and what you're doing it will of
24:11 vary. But you're just looking for points that are that are along
24:15 Okay now this devalue It's kind of different manufacturers of these products typically can
24:24 can have different parameters. They don't not necessarily consistent. Some some used
24:30 the parameter of 12 logs of How long to get 12 logs of
24:34 ? Okay. Others have you one log it depends. Okay um
24:40 so the factors that influence. All . So it could be certainly the
24:45 of microbes present. Okay. You a lot versus a little right.
24:49 can affect um It could be the . If it's an endospore former then
24:55 might be you know they're gonna be more resistant if they're mostly in those
25:00 that can certainly be more resistant. that can be consideration. Uh I
25:05 probably part of the of the most or practice from a practical standpoint,
25:11 really organic load. I would say two and exposure time, those organic
25:16 refers to you'll often see. But you look back at that can of
25:20 and the instructions, it likely said clean your surface with just a general
25:28 cleaner. Okay to get because of service is really dirty. Then that
25:35 interfere with the agent getting to the themselves. That's what organic loading organic
25:40 is kind of a level of how is the surface, is it full
25:42 organic material? Just dirt and grime what have you. So then you
25:47 then your agent won't work that well then it's the other extraneous material that's
25:54 the chemical and not getting to the themselves. So it's always good,
25:59 the surface is very dirty just to it with something else. First,
26:03 come in with your disinfectant, exposure time dose. Um Yeah,
26:11 . So that can relate to the itself. Um can have different volatilities
26:19 think of ethanol or isopropyl alcohol, disinfectant and antiseptic. Uh to something
26:29 um something that's not so volatile alcohol go into from liquid to gas rather
26:37 . Right vaporized. And so if spray it well then its lasting power
26:42 not gonna be that long compared to like like maybe detergent type of disinfectant
26:49 will stick on the surface longer. so so that can be a
26:54 Um And how long how long are leaving it there with the concentration of
26:58 kind of things? Okay ph and can be a concern um You know
27:06 temperature, it's hot right then. volatile. It's not gonna kind of
27:11 quicker. Right? Ph may affect how the chemical works. So that
27:16 be a consideration. Uh So again factors play into this. Okay of
27:24 when you're testing these things you try keep everything obviously everything constant and minimize
27:29 effects. Um But it's a you from a practical standpoint, you know
27:33 things things things to think about. the okay so here's the question.
27:39 is just testing you testing on the . Value, right? This this
27:46 require a calculator I don't think. , fingers were enough. So uh
27:53 is added to a culture containing 10 the six soc F. You so
27:58 call a colony forming unit. So think about that cells per mill is
28:03 . Uh And the the value of disinfectant is two minutes. So how
28:08 viable cells are left after eight So there's the devalue definition. Okay
28:16 value definition. Okay. All right down 1098. Okay there we
29:20 Okay so we get consensus says d what we got. So here is
29:27 we start with 10 and six. by definition then one leg of death
29:32 two minutes. Alright so So we two minutes we got 10-5. Uh
29:40 minutes 10 in the fourth eight minutes and third I'm sorry six minutes into
29:44 third. Eight minutes 10 to the . So yeah it's d okay um
29:52 questions about that. Okay. Alright. Um Alright so here is
30:01 couple of methods. A couple of that are commonly used to evaluate these
30:07 of antimicrobial agents. So the first these was called the use dilution
30:14 Okay you do a variation of this lab. Um We use glass beads
30:22 of metal rings but the purpose is it's a surface for the bacteria to
30:27 onto. Okay so you basically put rings and a culture of bacteria and
30:32 move the liquid and they kind of to the rings. Okay And then
30:37 add those two disinfectant solution incubate and um transferred to bras without disinfectant and
30:49 check for growth. Okay. To did they grow do they not
30:53 And that gives you kind of indication maybe it's bacteria static or bacteria
30:59 Um strictly it's strictly a quant Just visual you're looking for growth plus
31:06 minus. Okay. Are you seeing effect? It's kind of like a
31:11 pass you have a chemical you have favorite chemical or something, you want
31:14 check it out and then you know results say, okay maybe maybe then
31:19 can get more quantitative on it, ? It's kind of think of it
31:22 a screening screening tool to see how it works initially. Okay. And
31:29 gonna look at a problem involving this in a second. Um The second
31:33 uh a also a qualitative uh method what we call this confusion. You're
31:44 familiar with this I guess. Um we have a plate. Okay.
31:51 so what you do is um you the one you're not going to
31:58 You take a culture. Okay. of course it's very common to take
32:04 it's grand positive and grand mega. they're gonna you'll always see you typically
32:09 uh somebody they may behave differently but very common to see differences between the
32:14 because of the nature of that cell . Right? The gram negative the
32:18 it is versus the gram positive. does lead to differences and how they
32:22 to different types of chemicals. And in any case, so you start
32:27 a clean plate, un inoculated Okay then you have a culture.
32:32 what you do is you you lay growth. So you take a cotton
32:38 basically and you like a mop on floor. You just go all over
32:41 plate like this, right? And that does is you're not going for
32:47 pure culture. I speak plate isolation of a thing where you get individual
32:52 , you don't want you want the that you want a thick mat of
32:56 . Okay, So you do that then then you lay down these
33:03 So these disks have been soaked in concentration of in this example of these
33:10 chemicals. Okay. And so then can get disk and soak them anything
33:15 want really to test. And uh then take the disks and you place
33:21 on. You have to kind of get the excess chemicals off. But
33:26 you do that, then you plop them on top of the plate.
33:30 ? And so then of course you , right? Because that that long
33:35 bacteria you lay down will then grow like a big mat. Okay?
33:41 then if there's if the chemicals inhibiting , then you're gonna see that in
33:48 form of these clear zones around the . So, these discs there on
33:52 plate, okay, chemical in them diffuse out okay, into the surrounding
34:02 . Okay. And so you now to putting the discs on the
34:08 right? You put a big swab growth over everything. Right? So
34:13 question is, if these are, the dots are the cells you've put
34:21 as part of your making your man growth, Right? So the question
34:29 , will these grow or not? , Well they grow and if they
34:39 grow then you're gonna see something like . Texas chloramine, Right? There's
34:43 all over the place. Right? chemicals doing nothing to it,
34:47 It's able to unaffected by it. . But something like chlorine.
34:53 they didn't go anywhere near the Right? Because you have this
34:58 What you measure the zone of right? Measured right across the
35:04 That's an area of no growth Right? Just because the chemical that's
35:08 in the auger inhibited, they couldn't anything, right? They couldn't grow
35:13 . So that's basically how you assess you know, how big is the
35:17 area? Right? That gives you of a qualitative measure of how
35:22 Right. So you can see this is this is not a super
35:27 plate. A good plate has lots uh, what we call confluence,
35:33 growth is kind of growth altogether. looks the same, Right? Very
35:38 . Right? And so you should a nice crisp circle like you see
35:44 and not just a raggedy edge. . But nevertheless, the chlorine is
35:50 on both. Really? Okay. , it's kind of ugly over
35:53 but you see a big area Um and of course difference between gram
35:58 , gram positive be? No Right? Did have an effect here
36:02 the grand positive. That's what I . You always see differences between these
36:06 for certain chemicals. Okay. In case, just gives you a qualitative
36:12 see, okay, quick visual, work does not you can always get
36:15 technical with it from this point forward it's a good first pass kind of
36:20 thing. Okay um any questions about ? Yeah so let's look at this
36:28 . Alright this relates to the use problem. So we've got a growing
36:34 of grandpas it. Okay it's growing to mid log, okay middle of
36:40 and we're gonna add disinfectant. Okay it go for four hours and then
36:46 put it into fresh medium. So a visual of what's going on.
36:50 mid log add this in fact didn't my grammar and disinfectant. Okay and
37:01 four hours. Okay and so that's we're calling our initial. Okay then
37:10 going to take a sample of that put it into fresh media without
37:16 Okay and that next to we're calling subculture. Okay so no disinfectant subculture
37:26 here. Okay um then we see data. Right? So we have
37:32 you always do this with different delusions . Okay um to see if you
37:37 the effect the same effect with lesser of chemical. Right? Save money
37:41 way. Alright so looking for So that's why you always see a
37:45 of delusions here. Okay so we our initial right here. No
37:51 No growth no growth growth subculture growth growth growth. Okay again it can
37:58 just a visual looking for cloudiness or the case of initial increased cloudiness or
38:06 can you can take a spectrum tata measurement. Right? O.
38:10 Um And so this is the results see. Okay so uh what the
38:16 concentration this is disinfectant is. So that you can guess you know it
38:20 be something above this result somewhere one these three. Okay so would this
38:26 bacteria static bacterial sidle Or it has effect now we can all agree it
38:35 no effect that 1-1 28. Okay disregard that. Just answer it based
38:43 what you do see the effect. this is a variation kind of the
39:00 we talked about before. Like I there's lots of ways to do
39:58 Okay let's count down from 432 Okay. Right So 51 59 say
40:14 static. Um So who answered bacteria . Okay so why basically.
40:34 So basically this the subculture is assessing the state of the cells. So
40:39 was an effect. All right because didn't see that there was um we
40:45 that there was no growth further growth adding. So basically what's going on
40:50 right here they're all right so uh our experiment So we add um disinfectant
40:59 and then of course there's no growth right in our initial tube here except
41:05 the 1 to 1 28. So can imagine something like this may have
41:10 . Right if we continue the right? If there's no effect at
41:15 then it will continue to this mid and you just continue on until you
41:18 , completed its growth phase. But uh but we are sorry.
41:24 did see an effect though with these . Okay. Something like that.
41:28 then this is where you would take cells and put them into the
41:35 That's the second part of the Okay. At that point. So
41:40 what you're assessing is what's happened to cells, Are they alive or their
41:45 ? That's all you're trying to figure live or dead. Okay. And
41:49 way to do that is to say let's take them away from the
41:54 Put them in just a fresh medium any disinfectant and see if there actually
41:59 viable. So of course we found that's the case. Okay. They
42:04 . So that's that's classic bacterial static . Okay um if these had been
42:14 negative, okay then you could argue they're they're killed they weren't able they
42:21 killed in that treatment. Right? were not able to do anything once
42:25 put them in fresh media and disinfected grow because they died. Right.
42:31 that would be an indication then bacterial effect. Could you just based on
42:38 alone and nothing else Could you if did give you this result.
42:44 If you didn't didn't indeed see this the subculture could you tell if it's
42:50 , cyanobacteria lyric, just based on nothing else other than this anybody?
43:01 . Right. Because um without doing else. Right? You could look
43:07 the microscope but typically you you may see any difference between material. So
43:12 just know that they died, But you may not necessarily know how
43:16 died, but you know, in cases it doesn't matter. You kill
43:21 . That's what you wanted to Okay, so um so again,
43:26 can this can be a period you know, like all these little
43:32 we mentioned, right, whether this or the youth solution, this can
43:36 be these are kind of think of as kind of preliminary screenings. You
43:41 always get more involved, more quantitative you know, for people that work
43:47 this stuff, who are always looking different types of antimicrobial agents, it
43:53 to just have kind of a quick to see what's working and what's
43:56 And then work further with those that promising kind of a thing.
44:02 any questions about that? Okay, , so, uh actions of antimicrobial
44:10 . Okay, so you might you probably figure this out for yourself.
44:13 just thought about it for a second you know, chemical comes in contact
44:18 a cell. Right. What's it attack? Well, obviously, initially
44:22 attack the membrane, it can attack components inside the cell or the main
44:30 , proteins, nucleic acids. So the different ways they can affect
44:35 components. So there are what we detergent detergents have a chemical structure very
44:43 to fossil lipids that make up a so that enables them to dissolve
44:49 Uh The of course that leads to you break up and cell contents leak
44:55 . Sell license is killed affecting Remember proteins very specific what we call
45:03 structure. The chain itself folds in particular way that folding is important for
45:11 function. Okay. And if we it, so to speak, then
45:16 going to lose function likely be lethal itself. Okay. And there's different
45:22 to do that. You can do with acids, You can do it
45:25 other types of chemicals that interfere with interactions? Okay. Others can basically
45:32 completely break it down. Right. types of harsh acids and things.
45:36 nucleic acids as well can be radiation can break nucleic acids. So
45:44 all these are susceptible. Um So you look at the first of these
45:49 physical agents. So temperature um the uh mechanism to reduce microbial numbers in
45:59 types of chemical components self with So one thing to remember is that
46:07 depends on what you're trying to reduce microbial numbers in. What's the nature
46:13 your your um are you dealing with liquid? Are you dealing with a
46:19 ? Are you dealing with plastic Are you dealing with a liquid that's
46:24 a glass? Are you dealing with food product? So all all those
46:29 going to influence, you know what do? And does the treatment itself
46:34 ? Right. You may have a pipette tip box box, Full pipette
46:40 are using lab. How do you sterilize that? Right. And so
46:45 different ways to do it. Some better than others, Right? Liquids
46:48 particular. Right? Liquids aren't good terms of disinfecting them with radiation?
46:57 ? Um UV light for example, no good. Right? But temperature
47:01 really good. You can boil You can autoclave. So the point
47:05 it depends on what you're trying to . Okay. Which method works best
47:08 you. Okay. And so temperature very common. So the autoclave.
47:14 . Is the of course for lab rely on that to sterilize media.
47:20 so when you have steam under that's the key here. And to
47:26 honest, it's it's the auto play used to kill. And those
47:29 Right? So very resistant. But they are susceptible to uh that moist
47:36 that comes from steam and steam heated pressurized and heated to these extreme
47:41 So 121 is a temperature that that can't withstand. Okay, even a
47:50 thermal file. Okay. But generally don't need to worry about hypothermia?
47:55 because the things you claim you're not not trying to sterilize something from a
48:00 that will contain a hyper thermal Right? So it makes no
48:04 So the stuff you sterilize or things live at moderate temperature so it certainly
48:09 kill them. Okay. And the has that kind of penetration into a
48:14 effect. Um Now you can if don't have an autoclave, a lot
48:20 this, you know, if your to do with what's available to you
48:23 maybe you don't have an autoclave, what can you do? Well,
48:25 can use an oven. Okay. so incineration, that's if you're a
48:31 and your you have your loop, ? And you put it in the
48:34 burner, right? You're waiting for to glow, right? You're incinerating
48:39 right? You're you're sterilizing it as . Okay. Um so incineration,
48:44 air, right? So basically an , right convection of okay, is
48:50 reach these uh conditions but of course not gonna be the same as an
48:55 autoclave. These are standard conditions. per square inch will give you 100
49:01 C seven grade uh the equivalent and have to I wouldn't know this.
49:10 , but don't worry about these other . Okay. But there is a
49:16 can put things in the oven for uh temperature for a longer time and
49:22 can reach sterilization. Okay, um patronization. Right. So we're all
49:29 with that in the context of dairy products. Right. And so
49:37 there's been a number of so long time long temp. High temp
49:44 time. The low temp long time been around for a long time.
49:48 pun intended. Um That was one the first pasteurization methods developed and it
49:53 used for milk. I think now more common is I want to say
49:58 more common is certainly going to be temp short time. But ultra high
50:04 is not gaining more popularity. Um called ultra pasteurization um That 1 30
50:13 for 1 to 2 seconds. Um has really been beneficial uh for countries
50:20 refrigeration can be spotty. Okay, underdeveloped countries that may not have consistent
50:28 all over the place uh milk that treated that way can last for six
50:35 . Unrefrigerated. Okay, so that's that also requires you put the liquid
50:43 a sterilized container. Right? So it's but it's proven effective. It's
50:49 good. And of course with all methods that's about um preserving the
50:57 So you don't want to that that back to you can't autoclave everything.
51:01 ? So especially beverages for human you don't want to put milk in
51:06 autoclave. For example. Trust me will not come out good.
51:09 But so you have to use these methods to preserve the flavor, the
51:14 , the look, texture maybe of product. Um but you know,
51:20 it safe. Right, reduce microbial . So from milk pasteurization. This
51:26 here cox E ela is among the heat resistant. They don't form in
51:33 pores but they are among the more resistant types. So that's often used
51:39 a test organism forest for a milk process. Um Now physical agents.
51:50 continuing with temperatures so cold temp. ? So cold temp does not
51:55 okay, not kill it inhibits Of course. We refrigerate our food
52:00 in the refrigerator obviously to next to know, prolong maintain it. It
52:07 eventually spoil at some point typically. But it does prolong that the refrigeration
52:13 for that slowing growth. We use the lab to preserve cultures,
52:17 We can grow a culture up. can add What you might call antifreeze
52:23 it, a little bit of a of drops of glycerol and they can
52:27 at -80 and be viable for Okay. Um the uh the uh
52:37 problem with this one problematic bacterium is guy listeria. We'll talk about that
52:43 the end of the semester in the . But this is what actually grows
52:47 refrigeration temperature. So um if you not one to necessarily pay attention to
52:55 dates like me, I'll eat food has to has to still smell.
53:02 . Alright. I do have my . But uh you've likely have ingested
53:08 find it like processed meats like hot and salami and deli meats you know
53:15 those kind of things. Uh and they can actively grow at 4° for
53:23 , not fast, but they you you'll see logs of growth over a
53:27 or four week period. Um but also when it's a pathogen of course
53:33 it can uh most people that have immune systems aren't affected by it,
53:38 it can pregnant mothers need to be of it to not really eat these
53:44 of processed foods during the pregnancy because can affect the baby. Okay,
53:50 the unborn fetus. And so uh like I said, we'll talk about
53:54 later, but it is, it a no wonder the bluebell, there
53:58 a uh blue bell ice cream factory affected by a Listeria outbreak. A
54:04 fatalities occurred. This was probably eight ago, I think. And you
54:09 , google ice cream, right? refrigeration temperatures to make it. And
54:13 you're not careful, listeria can grow those conditions and it did and it
54:17 traced back to not cleaning their equipment . Um so filtration again, these
54:25 for liquids so that this term um label. Okay, this refers to
54:32 sensitive. They're sensitive to heat the them too much, basically fall
54:37 Okay, um so filtration is Um you hear the term filter
54:45 Okay, technically it's not sterilization because can get through, but honestly viruses
54:54 on a problem typically in this Um you can have air filtration for
55:00 . Have filters can remove microbes from air. Um The uh and there
55:06 certain things that just aren't amenable to ng or high heat. And we
55:11 um there's a media we have in lab that we can't use on it
55:16 all. So we have to filter Yuria broth. Um Others have to
55:21 can't be article you have to be boil gently so it just depends on
55:24 nature of the of the liquid. Other ones I'm not gonna go into
55:29 no high pressure has been used desiccation out, drying it freeze drying osmotic
55:37 . Uh So there are osmotic pressure that's probably been used for centuries as
55:44 preservation method that's packing foods and salt been used for centuries packing meat,
55:52 and salt salt itself of course creates hyper tonic environment that's gonna be
55:59 Um Of course we're moving water Because life needs water and move
56:03 That can certainly be inhibitory. So radiation. So this can be effective
56:16 Remember with radiation it's about energy. ? So high energy radiation is gonna
56:23 more effective at killing than lower Okay and so the two that we're
56:29 with here is UV light what we non ionizing radiation. And so that
56:36 so you b that's good for surface shining UV lamp on an area can
56:43 the surface. Um It works by bases in D. N.
56:49 Creating mutations that can be ultimately be to the microbe but it's easily blocked
56:56 a shirt can block it. Often we used to in lab have an
57:02 where we bombarded the culture with UV . If you forgot to take the
57:06 without the Petri dish, that would the UV light from hitting the
57:09 So it doesn't take a lot to UV light. Right? So you
57:13 want to use it certainly for liquids for surface it can be useful but
57:19 high energy are is UV light and rays. So look at the wavelength
57:26 100 nanometers for you be like for radiation gets um point less than 1000.0.1
57:34 . It's very small. Super high . And uh radiation is used for
57:41 these on meat, frozen, frozen . It's been your created use it
57:46 that. Um And other uses on like plastics have been used to being
57:54 with radiation. So it has its and it is it can be a
57:59 method for sure. Right? So breaks nucleic acids. You're doing
58:04 You're certainly going to kill the Okay. Um the and it is
58:10 more penetrating. So it's not easily by a shirt or plastic lid.
58:16 ? It can penetrate and you know because you have to wear a lead
58:21 if you're getting a Dell X Okay. Or other type of X
58:26 . Um Now chemicals so things like sanitizers um final IX. Often these
58:41 sanitizers, the phone Alex tend to types of things that um uh stick
58:50 to the surfaces. They are not easily vaporized. Okay. Have a
58:54 better staying power and they have a of effects. They basically break down
58:59 . Break down the clinic. Gasses halogen are things like iodine base of
59:05 doctor's office. You may have seen of this, this yellowish liquid beta
59:11 iodine is iodine based bleach is in category. So these basically again,
59:17 lot of these things overlap in terms what they affect can affect protein
59:22 Uh Bleach is an oxidizing agent. down chemicals in the cell alcohols,
59:29 groups that we use this in lab disinfectant. Um these work better.
59:37 add water to it. Right? we use 70% ethanol, okay,
59:45 works better than like say 95 or 100%. Right, the extra water
59:52 there helps it penetrate the membrane is and let's not get in there and
59:57 . Okay, a little bit, little bit of water helps actually.
60:02 , and so these of course dissolve dissolve membranes. Okay, heavy metals
60:10 you often see this in um uh you have an aquarium, you often
60:17 these agents to prevent algae growth in aquarium and they often contain one of
60:23 metals to prevent growth of allergy for example. Um But the thing with
60:29 metals is a little bit goes a way. You can overdo it rather
60:34 with with these because they'll be quite . So um usage and concentration is
60:41 important with these things. Too much be certainly be a hazard um surface
60:48 . This this is what I call the detergent type molecules. And they
60:53 very similar to you can see how very very similar to a phosphor
60:58 Okay. And so because of that very good at penetrating membrane and disrupting
61:05 dissolving it in time. Um Chemical . So organic gasses. So this
61:12 are things you find in very commonly different foods like bread. Um And
61:20 kind of based food cereals, things that. Um Also in cosmetics contain
61:27 . So and they kind of fit category here where you see sabic acid
61:34 , if you look on a cereal label or other food level, you
61:38 citrate or citric acid is in there have the same effect. And the
61:42 they have is this so let me get this out of the way.
61:48 So here for example is this is Zoellick acid I think. Um So
61:53 happens is in solution solution. It forms an acid all right.
62:03 so but unlike hydrochloric acid. hcl of course goes to and this
62:14 what we call a strong acid. other words, it all goes to
62:21 flooring and protons, right? There's of this left in solution. That's
62:26 nature of a strong acid, All goes to. That's why it's
62:31 . It all goes to these protons chloride ions. Okay, this
62:36 these things, organic acids are weak . Okay, so what that means
62:44 it doesn't all go to product. , you'll see this, this and
62:54 in solution. Okay, so, what, so what is this
62:59 Okay. The fact that you still some of that reactant here.
63:05 in that's neutral there's no charge associated it relatively small so we can fit
63:12 a membrane and get inside the Okay, So inside the cell this
63:18 and then this reaction occurs. And it acidified eyes the inside of the
63:24 as it comes in and that's inhibitory . That's the preservative action of the
63:31 , of the of the chemicals in food or in the cosmetic. It
63:35 that action in the cell and uh inhibits growth. That's that's why it
63:41 as a preservative. Okay. But the fact that it is a weak
63:46 . Only a little bit of this this way. And so this is
63:50 neutral compound that can squeeze in again the cell. Okay, very common
63:56 and lots of foods. You'd be . Um gas is sterling's.
64:01 so these are typically used for really different types of products. Alright,
64:10 really lab lots of lab products. things like your pipette tip boxes,
64:16 other plastics, Petri dishes not Uh and so gas a gas can
64:23 fairly well. You wouldn't want to a gas to sterilize liquid because that's
64:26 gonna mix very well. But for things like this it can it can
64:32 and it has this kind of effect it can be sterilizing. So it
64:37 this kind of structure here in the of acid or base, it kind
64:42 unfolds and then becomes very reactive. reacts with proteins and nucleic acids in
64:49 cell basically destroying their functions. And but it's kind of a chain reaction
64:54 very quickly and quickly forms these reactive products that basically destroy the components in
65:00 cell rather quickly. Okay, so , for heat sensitive material.
65:06 plastics very common. So um the . So you might think,
65:16 we're certainly aware of antibiotic resistance and talk about that later in the
65:22 but you might go, okay, about disinfectants? Antiseptics? Can microbes
65:27 resistant to those? Yes and Generally, no. Okay. Because
65:35 the varied targets that these chemicals So think about, you know,
65:40 chemical chemical like I saw right, contact the cell can likely have an
65:46 on the membrane and get inside and various proteins and nucleic acids and
65:50 So in order for a cell to resistant, it's gonna have to have
65:57 way to counter act each and every ? Okay. That would mean equate
66:03 having lots of different mutations to counteract effect. That effect this and this
66:09 this. The probability of that is unlikely. Okay. Um that's why
66:18 antibiotics, antibiotics have only like a target. Right? So comparatively
66:24 it's a little easier to become resistant you're only having to change one thing
66:29 become resistant whereas with a disinfectant antiseptic things have to change. Okay.
66:35 it's not likely unless right. Unless don't use the chemical at the proper
66:42 if you want to save money or your reasoning is and you severely reduce
66:49 concentration you use then then the effect this is less. The number of
66:56 is less. Okay. And then do have the likelihood of becoming resistant
67:02 the disinfectant or antiseptic. Okay. generally no. Okay. Or not
67:09 likely. Okay. Um Now in of uh as a function of microbe
67:18 . Okay. In resistance. So you see that Priam's was in
67:23 sport is not surprising are very resistant the effects because of that thick
67:29 Right. But prion surprising are resistant well. But then you go down
67:34 to you know, gram negative versus positive. Okay. You see the
67:40 negative more resistant that that outer membrane providing a protective covering if you will
67:48 terms of um action against disinfectants and . So, you know, it
67:54 . Okay. What uh what Certainly in a healthcare setting, what
68:01 um makes it more difficult to become ? Is the fact that when you
68:07 hospitals obviously are clean. Yeah. cleaning rotation of using different disinfectants on
68:15 rotating basis. So maybe for one they'll use an alcohol. Then the
68:22 time they clean in two weeks or , they use a detergent type.
68:27 they switch to a different you're constantly different types of disinfectants. That too
68:32 increases the probability that you're not gonna resistant. So it's uh so but
68:39 with antibiotics which we'll talk about later they they do and obviously we're aware
68:45 resistant types. Okay. Um Many . Okay. All right, okay
68:54 , that's all. Any questions writing test or that material let me
69:19 Thank you. What do you mean you say etcetera? Where?
69:35 who discovered them? They would hook etcetera. Those names?
69:45 Right. Who discovered them? Where they come? Who what?
69:52 ? When where kind of thing? .
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