Transcript Platform Presentation

The Antibiotic Sensitivity Test
Presented by Marian Mikhail
Undergraduate student
Biology Major
Health and Science Concentration
Tennessee Tech University
Cookeville, Tennessee 38505
Introduction
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Problem: susceptibly or resistance of bacteria to antibiotics
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“All isolates should be tested by Kirby Bauer disc
diffusion test on Muller- Hinton agar plate according to the
standard procedure outlined in national committee for
clinical laboratory standards (Briggs 1999).”
Salmonella typhi in asymptomatic typhoid and to find out
drug resistance and ability of strains to transmit drug
resistance to other bacteria (senthilkumar and prabakaran
2005).”
“Determine the susceptibility of an opportunistic pathogen
to antimicrobial agent (Goss 2007).”
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
Introduction
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“Shigella isolates resistant to a variety of agents
have been reported in the united states (Ashkenazi
1994).”
“The routine use of antibiotics in medical and
agricultural circles has resulted in widespread
antibiotic resistance and in the development of
genetic mechanisms efficient for the dissemination
of antibiotic gene cassettes, especially within and
between species of gram-negative organisms
(Briggs 1999).”
Introduction


“Prevention monitoring program has detected the
first U.S. case of Shigella infection resistant to the
fluoroquinolone (moon2003).”
“chloramphenicol was the first-line drug of choice,
and in developed countries its use resulted in a
reduction in mortality rates from 10% to <2%. After
extensive outbreaks of typhoid fever occurred in
Mexico and India in the early and mid-1970s, in
which epidemic strains were resistant to
chloramphenicol , the efficacy of this
antimicrobial was in doubt(John et al 1999).”
Objective ,hypothesis, Null
hypothesis
Objective :to show Antibiotics sensitivity test (disc
diffusion method) importance in determining the
proper antibiotics treatment in different species in
enterobacteriaceae family.
Hypothesis: different species in the same bacterial
family like the enterobacteriaceae family (gram negative
rods) will have different susceptibility or resistance to
antibiotics
Null hypothesis: different species in the same bacterial
family like the enterobacteriaceae family (gram negative
rods) will have the same susceptibility or resistance to
antibiotics
Methods and materials
Materials:
antibiotics plate Muller –
Hinton plate)- antibiotics –different
species of bacteria in the
enterobacteriacae family-proper
antiseptic technique
EXPERIMENTAL DESIGN (Goss 2007).
Disc diffusion method
Data
Interpretation table
Methods and materials
Antibiotics used in the experiment
AM-ampicillin 10mg
TE-tetracycline 30mg
CIP-ciprofloxacin 5mg
GM-gentamycin 10mg
Bacteria used in the experiment
Escherichia coli ,Escherichia coli O157:H7, Shigella
boydii Shigella sonnei,Yesinia enterocolitica Kelebsilla
pneumoniae,Providencia stuartii,Morganella morganii
Salmonella typhumurium, salmonella typhi
Results
 Formation of zone of inhibition
 Measuring the zone of inhibition
 The greater the inhibition zone that
means that the bacteria are
susceptible to antibiotics
 The lesser the inhibition zone that
means that bacteria are resistant
to antibiotics
 If no zone of inhibition is formed
that means that the bacteria are
resistant to antibiotics
RESULTS
Bacteria
AM
TE
CIP
GM
1-E-coli
17/S
19/S
30/S
19/S
2-E-coli
O157:H7
17/S
18/I
29/S
15/S
3-Shigella
boydii
20/S
20/S
40/S
15/S
4-Shigella
sonnei,
19/S
20/S
35/S
12/R
5-yersinia
0/R
20/S
33/S
17/S
6-Kelebsilla
0/R
16/I
40/S
12/S
7-Providencia
0/R
0/R
32/S
13/I
8-Morganella
0/R
21/S
40/S
17/S
9-Salmonella
tyhi
17/S
17/S
32/S
19/S
10Salmonella
typhimurium
25/S
17/I
35/S
17/S
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Statistics of the zone of inhibition of this
family:
mean =
=786/40=19.65mm
Results
1-E-coli
2- E-coli O157:H7
3-shigella boydii
4-shigella sonnei
5-yersinia
6-Kelebsilla
7-Providencia
8-Morganella
9-Salmonella
Tyhi
10-Salmonella typhimurium
suspectibility and resistance to antibiotics
40
35
30
Diameter of 25
the zone of
20
inhibition
15
(mm)
10
AM
TE
CIP
GM
5
0
1
2
3
4
5
6
Bacteria
7
8
9
10
DICUSSION
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“ The disc sensitivity test has therefore been the
main method by which we have been determined
the susceptibility of organisms and by which we
have kept track on resistance itself (Kerr 2007).”
“salmonella typhi have remained uniformly
susceptible to quionlones and third generation
cephalosporins antibiotics although the clinical
response to cephalosporins is significantly become
inferior(wain).”
Discussion
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“All pathogenic Yersinia enterocolitica strains isolated in our
laboratory belonged to serogroup O3 (biotype 4). From
1985 to 1987, we isolated 75 strains. They were all resistant
to ampicillin and cephalothin but were susceptible to coamoxiclav, cefotaxime, tetracyclines, gentamicin, and nalidixic
acid. Seventy-two percent were resistant to streptomycin,
45% were resistant to sulfonamides, 28% were resistant to
trimethoprim-sulfamethoxazole, and 20% were resistant to
chloramphenicol. Only 20 strains were isolated throughout the
period from 1995 to 1998. All were resistant to ampicillin and
cephalothin but were susceptible to co-amoxiclav, cefotaxime,
gentamicin, and ciprofloxacin. The rate of resistance increased
up to 90% for streptomycin and sulfonamides, 70% for
trimethoprim-sulfamethoxazole, 60% for chloramphenicol, and
5% for nalidixic acid(Prats 2000).”
Discussion
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“resistant kelebsiella to gentamycin were
isolated from more than one body site but
the urinary and respiratory tract were
involved in each case(Rennnie 1976).”
“The relative antimicrobial susceptibilities of
different Shigella spp. may vary
geographically (Chu 1998).”
CONCLUSION
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After running this experiment, I will accept my hypothesis
because there are different susceptibility and resistant to
antibiotics in the same family like in kelebsiella ,yersenia , and
shigella and they are all in the same family
Ciprofloxacin is the best drug for treatment of diseases caused
by enteriobacteriacae family but we have to do the antibiotic
sensitivity test before giving the drug because peoples in
different area develop different resistance and susceptibility to
antibiotics and in my experiment I was dealing with the lab
bacteria.
The main reason for resistance is the overuse of antibiotics
especially if people take medicine without doing the antibiotic
sensitivity test , that will develop resistance.
I would like to thank you for your
attention
Questions