Antibiotics resistance by bacteria and transmission of resistance This file will tell about how antibiotics resistance is occurred and how it get transmitted from one bacterium to another.

1. Name: Malaika muskan
Roll no. 875
University roll no. 023793
Dept. ZOOLOGY
Semester : 7th
Subject: Microbiology
Topic of assignment:
Antibiotics and transmission
of resistance
Submitted to;
prof. fazal illahi butt
Govt. college of science, wahdat road
Lahore.

2. Transmission of antibiotics resistance

3. Introduction:
 Definition:
It is a special type of chemotherapeutic
agent usually obtained from the living
organisms. It also refer to the metabolic
products of one organisms that is in very small
amount is determined or inhibitory to other
microorganisms.
 Example: penicillin, ampicillin, cephalosporin
etc.

4. Antibiotics
 In this the metabolic products of one microorganisms
use as a inhibitory or determinant for the other
microorganisms.
 It is like the competition that one creature destroy the
other to sustain its own life, just like bacteria produce
resistance against antibiotics to sustain their life.

5. Characteristics:
 There are following characteristics of the antibiotics
that should be present in the useful antibiotics:
1. They should be broad spectrum
2. They should prevent the ready development of
resistant form of parasites.
3. They should be non-dangerous, i-e. should not
produce side effects on host like, sensitivity, or allergic
reactions , nerve damage, irritation of kidney and
gastrointestinal tract.
4. They should not eliminate the normal useful flora of
the host body.

6. Mechanism of antibiotic action:
 The main points of the attack of antibiotics on the
microorganisms includes
Inhibition of cell wall synthesis
Damage of the cytoplasmic membrane
Inhibition of nucleic acid and protein synthesis
Inhibition of specific enzyme system

8. Development of resistance:
Antibiotic resistance can be produce due to following
factors;
 Development of alternate metabolic pathway
 Production of altered enzymes that is not affected by
drug
 Synthesis of excess enzymes to overcome the drug
effect
 Alteration of the cell membrane
 Alteration of protein structure

10. Transmission of resistance:
 Resistance which bacteria develop against the
antibiotics transmit from the super bug to the other
members of the colony to survive against the drug,
called transmission of the resistance.
 This is suggested that this transmission occur by the
following process:
1. Conjugation
2. Transduction
3. Transformation
 The most common method is conjugation.

12. Experiment
 The main reason of the transmission is the transfer of resistant gene
from donor to the recipient by the plasmid (the extra chromosomal
DNA).
 Two Japanese scientists; akiba and ochiai, first reported the transfer of
resistance through conjugation by their experiment.
 They isolate both antibiotic sensitive and antibiotic resistant organisms
of the same serotype from the patient with entire infection being
treated with antibiotics. They went to demonstrate that this was due to
the resistant gene in the reservoir of E.coli in the intestinal tract being
transferred to the shigella dysenteriae that caused the infection and
the transfer of resistant gene of antibiotics has been observed by
conjugation.

13. Comparison:
Transformation Transduction
 Bacteria take up DNA
floating in the environment.
 By this bacteria can
reproduce, transport the
genetic material, antibiotic
resistant genes etc .
 DNA is accidently moved
from one bacterium to
another by a virus.
 Bacteria can also reproduce
by this and rarely transfer the
genes of metabolites.

15. Conjugation
 Bacterial conjugation is a transfer of genetic between
bacterial cells by the cell to cell direct contact or by a
bright like connection between two cells. This take place
through a pillus.
 In conjugation, a donor cell provide a mobilizable
genetic element that is most often plasmid. Most
plasmids have system to ensure that the recipient cells
does not have the same element already.
 The genetic information transferred is often beneficial to
the recipient. Benefits any be antibiotic resistance,
xenobiotic tolerance or the ability to use new
metabolites.

17. “Gram negative bacteria is
more resistant to the gram
positive bacteria”

18. Gram positive bacteria:
 Gram positive bacteria is less resistant to the
antibiotics because their cell membrane form from the
a lot of peptidoglycan that are easier to kill, their thick
peptidoglycan absorbs easily antibiotics and cleaning
products.
 Gram positive bacteria don’t have outer envelop
(porins) like in gram negative bacteria, so they unable
to mutate against the resistance.

19. Gram negative bacteria:
 Gram negative bacteria contain an envelop of three
layers outer their cell body that is form of
phospholipids, lipopolysachhrides and porins.
 Gram negative bacteria is more resistant to antibiotics
because they have outer membrane form of
phospholipids, lipopolysachhrides and some outer
membrane proteins like porins by which they can alter
or mutate their outer coverings to become resistant.

20. 1. Avoiding the discriminate use of antibioticswhere they are
of no realclinical value
2. Refraining from he use of antibiotics commonlyemployed
for generalized infection for tropical applications.
3. Usningcorrect dosage of proper antibiotic to overcomean
infection quickly.
4. Usingcombination of antibiotics of proved effectiveness.
5. Usinga different antibiotic when an give evidence of
becoming resistant to used initiall.