Antibiotics are medicines that fight infections caused by bacteria in humans and animals by either killing the bacteria or making it difficult for the bacteria to grow and multiply. Bacteria are germs

1. Antibiotics
Botany Assignment
Submitted by :
ABHISHEK SONI
B.Sc. 1st Sem Microbiology
Submitted to :
Dr . SANGHMITRA
Head of deparment of Botany Govt.
P.G. College Noida
GOVT. P.G. GOLLEGE NOIDA
SEC-39

2. ANTIBIOTICS
KEY POINTS :
 what is antibiotic
 Classification
 Use
 Resistance and cross -resistance
 Possible Side Effects
 Characteristic of Ideal antibiotic

3. What is antibiotic
 an antibiotic is a naturally occurring semi – synthetic or synthetic type of agent that destroy o
inhibit growth of microorganism.
 Natural - mainly from soil bacteria & fungal sources.
 Semi- Synthetic - chemically altered chemical compound.
 Synthetic - chemically designed in the lab.
 the term antibiotic first used in 1942 by Selman Waksman .
 1st Antibiotic discovered by scientist alexander Fleming in 1928 is penicillin.
 he was working in his lab and trying to kill deadly bacteria when he noticed Blue mould growing on
dish .

4. Classification of antibiotics
 Antibiotics are classified in several ways :
1. on the basis of mechanism of action.
2. on the basis of basis of spectrum of antimicrobial activity.
3. on the basis of mode of action.
 Classification : On the basis of mechanism of action
1. Protein synthesis inhibitor -
 inhibit 30s subunit : Aminoglycosides (gentamycin), tetracyclines.
 Inhibit 50s subunit : Clindamycin, Chloramphenicol, Macrolides
1. Cell wall synthesis inhibitor - penicillin and cephalosporins.
2. DNA & Synthesis inhibitor - metronidazole , fluoroquinolones (Ciprofloxacin)
3. RNA Synthesis inhibitor - Rifampin
4. Folic Acid inhibitor - Sulfonamides

5. On the basis of spectrum of activity
 On the basis of spectrum of activity antibiotics are classified as :
 Board Spectrum Antibiotics : the term board spectrum antibiotics refers to an antibiotic
that’s act against wide range of disease causing bacteria.
 tetracycline
 amoxicillin
 Erythromycin
 short acting antibiotics : use to treat narrow range of disease causing -bacteria
 Azithromycin , Penicillin G
 Clarithromycin.
 Clindamycin

6. On the basis of mode of action
 On the basis of mode of action antibiotics are classified as :
 Bacteriostatic antibiotics - is a biological or chemical agent that stops bacteria
from reproducing , while not necessarily killing them otherwise.
 Tetracycline
 chloramphenicol
 Erythromycin
 Bacteriocidal antibiotics- is a biological or chemical agent that kills the bacteria
 Cephalosporin
 Penicillin
 Clotrimazole

7. Uses
 Pneumonia
 Sepsis
 Meningitis
 Gall infection
 Fungal infection
 Skin infection
 Mucus membrane infection
 Gynecologic infection
 Ent infection
 Diphtheria
 Quinsy
 Scarlet Fever
 Siberian Ulcer
 And in many more disease causing bacteria.

8. Contraindications
 Hypersensitivity
 Renal Disease
 Hepatic Disease
 Pregnancy (First trimester)
 Blood Dyscrasias.
 CNS disorders
 Chronic Alcholism.

9. Resistance & Cross Resistance
 Resistance:
 If the concentration of drug requires to inhibit or kill the microorganism is great or less
then the normal use then the microorganism is considered to be resistant to that drug.
 Cross – Resistance :
 Cross resistance to a particular antibiotic that often results in resistance to other antibiotic,
usually from a similar chemical class, to which the bacteria may no have been exposed.
 For – Example
 Clindamycin & Lincomycin.

10. Possible Side Effects
 Although there is a long list of side effects but some of them are listed below.
 Diarrhea
 Bloating
 Indigestion
 Abdominal pain
 Loss of appetite
 Being sick
 Feeling sick
 Itchy Skin rash
 Coughing

11. Characteristics of Ideal antibiotics
 An ideal antibiotic should: be broad spectrum in action, i.e, it should act
against a wide variety of different pathogenic microbes. For instance, it should
not only act against different strains of the same bacterial species but also on
different types of bacterial such as Gram positive and Gram negative bacteria.
 have no toxic or side effect on the host.
 not affect the normal microflora (microbes that normally inhabit the bodies of
healthy organisms) of the host.
 take very less time to start working against pathogens within the body.

12. THANK YOU !!
PRESENTED BY : ABHISHEK SONI
B.Sc (Biology)
GOVT PG COLLEGE NOIDA SEC -39