Hey everybody, Dr O here. In this video we are going to cover the common bacterial shapes, and arrangements So I’ll just go right through the list here So first we have a coccus So coccus would be singular cocci would be plural That’s going to be a round or spherical cell Basilus means rod, so technically the basilus can be used in two ways Like uh, basilus is used as a name And as a shape So my name is Frank, right So Frank would be my name, but frank would also be a hotdog, I guess So uh, um so, If you see basilus and it’s capitalized and it’s part of the name of the organism It is part of it’s name, but it is also telling you that it has a rod like shape So coccus means sphere, a spherical organism Basilus means rod Next we have vibrio, it’s technically a curved rod But they look like a comma So there’s so many examples of the cocci and the basilus that we’ll cover them as we go But really the only key example of vibrio that we are going to talk about very much is vibrio cholerae The causative agent of cholera Next we have the coccobasilus These are actually short rods But they are so short that they can look like spheres So can be misinterpreted sometimes So a coccibasilus is a short rod Quite a few examples here Important ones, let’s see, haemophilus influenzae Which can cause meningitis Bordetello pertussis, which can cause whooping cough Those would both be examples of coccobasilus or coccobasili organisms Next we have the spirilums These are rigid large organisms that are spiral or cork shaped Not really any important clinical examples here But I do want to point out that the spirilum and the spirochetes They’re both examples of spiral organisms But theres a couple clear differences here Spirochetes are also going to be corkscrew shaped They’re going to be more flexible But here’s the key difference The spirilum organisms, they’re going to be propelled by flagella on their ends The spirochetes , they use a special type of flagella which is called an axial filament So that’s going to be the key difference there And then clinically the spirochetes are going to be a lot more important. The two key spirochetes I can think of here would be treponema pallidum Which is the causative agent of syphilis And borelia burgdorferi which is the causative agent of lime disease And there are other ones Alright so those are the basic cell shapes Say that three times fast Coccus, basilus, vibrio, coccobasilus, spirilum and spirochete Now lets move on to the cell arrangements So if you have just a single organism it would be a coccus or basilus no need to go over that again Diplo means two, so if you have a pair of spheres it would be a diplococcus A pair of rods would be a diplobasilus The most important diplococcus would be the streptococcus pneumoniae I know the name tells you it would be in chains But it’s a diplococcus most of the time Tetrad, we don’t talk about that much That’d be a group of 4 If you want to go even further to a group of 8 That’s called a sarcinae But that’s not a big deal But the two key ones here are strepto, which means chain Staphylo means cluster, sorry So you think stepto and staphylo and then coccus and basilus Most of the organisms we talk about are going to need those terms to describe them So strepto meas chain, staphylo means cluster Now notice here we have a streptococcus and we have a staphylococcus But we do not have a staphylobasilus So a streptobasilus is a chain of rods But rods don’t actually grow in clusters And that’s because rods grow end to end They don’t grow side to side So if you see a cluster of rods it’s because they’re in a pile It’s not because they grew that way So there is no staphylobasilus Okay, so those are going to be all your key terms as far as cell shape and cell arrangement For your bacteria Have a wonderful day Be blessed