The Antibiotic Sensitivity The Antibiotic Sensitivity TestTest

Presented by Marian MikhailPresented by Marian MikhailUndergraduate studentUndergraduate student

Biology MajorBiology Major Health and Science Concentration Health and Science Concentration

Tennessee Tech University Tennessee Tech University Cookeville, Tennessee 38505Cookeville, Tennessee 38505

Introduction Introduction Problem: susceptibly or resistance of bacteria to Problem: susceptibly or resistance of bacteria to

antibioticsantibiotics

“ “All isolates should be tested by Kirby Bauer disc All isolates should be tested by Kirby Bauer disc diffusion test on Muller- Hinton agar plate diffusion test on Muller- Hinton agar plate according to the standard procedure outlined in according to the standard procedure outlined in national committee for clinical laboratory national committee for clinical laboratory standards (Briggs 1999).”standards (Briggs 1999).”

Salmonella typhiSalmonella typhi in asymptomatic typhoid and to in asymptomatic typhoid and to find out drug resistance and ability of strains to find out drug resistance and ability of strains to transmit drug resistance to other bacteria transmit drug resistance to other bacteria (senthilkumar and prabakaran 2005).”(senthilkumar and prabakaran 2005).”

““Determine the susceptibility of an opportunistic Determine the susceptibility of an opportunistic pathogen to antimicrobial agent (Goss 2007).”pathogen to antimicrobial agent (Goss 2007).”

Introduction Introduction

““ShigellaShigella isolates resistant to a variety of isolates resistant to a variety of agents have been reported in the united agents have been reported in the united states (Ashkenazi 1994).”states (Ashkenazi 1994).”

““The routine use of antibiotics in medical The routine use of antibiotics in medical and agricultural circles has resulted in and agricultural circles has resulted in widespread antibiotic resistance and in widespread antibiotic resistance and in the development of genetic mechanisms the development of genetic mechanisms efficient for the dissemination of efficient for the dissemination of antibiotic gene cassettes, especially antibiotic gene cassettes, especially within and between species of gram-within and between species of gram-negative organisms (Briggsnegative organisms (Briggs 1999).”1999).”

Introduction Introduction ““Prevention monitoring program has detected Prevention monitoring program has detected

the first U.S. case of Shigella infection the first U.S. case of Shigella infection resistant to the fluoroquinolone (moon2003).”resistant to the fluoroquinolone (moon2003).”

““chloramphenicol was the first-line drug of chloramphenicol was the first-line drug of choice, and in developed countries its use choice, and in developed countries its use resulted in a reduction in mortality rates from resulted in a reduction in mortality rates from 10% to <2%. After extensive outbreaks of 10% to <2%. After extensive outbreaks of typhoid fever occurred in Mexico and India in typhoid fever occurred in Mexico and India in the early and mid-1970s, in which epidemic the early and mid-1970s, in which epidemic strains were resistant to chloramphenicol , strains were resistant to chloramphenicol , the efficacy of this antimicrobial was in the efficacy of this antimicrobial was in doubt(John et al 1999).”doubt(John et al 1999).”

Objective ,hypothesis, Null Objective ,hypothesis, Null hypothesishypothesis

ObjectiveObjective :to show Antibiotics sensitivity test :to show Antibiotics sensitivity test (disc diffusion method) importance in (disc diffusion method) importance in determining the proper antibiotics treatment determining the proper antibiotics treatment in different species in enterobacteriaceae in different species in enterobacteriaceae family.family.

HypothesisHypothesis: different species in the same : different species in the same bacterial family like the enterobacteriaceae bacterial family like the enterobacteriaceae family (gram negative rods) will have different family (gram negative rods) will have different susceptibility or resistance to antibioticssusceptibility or resistance to antibiotics

Null hypothesisNull hypothesis: different species in the same : different species in the same bacterial family like the enterobacteriaceae bacterial family like the enterobacteriaceae family (gram negative rods) will have the family (gram negative rods) will have the same susceptibility or resistance to antibioticssame 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 techniqueEXPERIMENTAL DESIGN (Goss 2007).Disc diffusion methodData 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-Salmonellatyhi

17/S 17/S 32/S 19/S

10-Salmonella typhimurium

25/S 17/I 35/S 17/S

Statistics of the zone of inhibition Statistics of the zone of inhibition of this family:of this family:

mean =mean =

=786/40=19.65mm=786/40=19.65mm

Results Results

0

5

10

15

20

25

30

35

40

Diameter of the zone of inhibition

(mm)

1 2 3 4 5 6 7 8 9 10

Bacteria

suspectibility and resistance to antibiotics

AM

TE

CIP

GM

1-E-coli1-E-coli

2- 2- E-coli O157:H7E-coli O157:H7

3-shigella boydii3-shigella boydii

4-shigella sonnei4-shigella sonnei

5-yersinia5-yersinia

6-Kelebsilla6-Kelebsilla

7-Providencia7-Providencia

8-Morganella8-Morganella

9-Salmonella9-Salmonella

TyhiTyhi

10-Salmonella typhimurium10-Salmonella typhimurium

DICUSSION DICUSSION

“ “ The disc sensitivity test has therefore been The disc sensitivity test has therefore been the main method by which we have been the main method by which we have been determined the susceptibility of organisms determined the susceptibility of organisms and by which we have kept track on and by which we have kept track on resistance itself (Kerr 2007).” resistance itself (Kerr 2007).”

““salmonella typhisalmonella typhi have remained uniformly have remained uniformly susceptible to quionlones and third susceptible to quionlones and third generation cephalosporins antibiotics generation cephalosporins antibiotics although the clinical response to although the clinical response to cephalosporins is significantly become cephalosporins is significantly become inferior(wain).”inferior(wain).”

Discussion Discussion

““All pathogenic All pathogenic Yersinia enterocoliticaYersinia enterocolitica strains isolated in our strains isolated in our laboratory belonged to serogroup O3 (biotype 4). From laboratory belonged to serogroup O3 (biotype 4). From 1985 to 1987, we isolated 75 strains. They were all resistant 1985 to 1987, we isolated 75 strains. They were all resistant to ampicillin and cephalothin but were susceptible to co-to ampicillin and cephalothin but were susceptible to co-amoxiclav, cefotaxime, tetracyclines, gentamicin, and amoxiclav, cefotaxime, tetracyclines, gentamicin, and nalidixic acid. Seventy-two percent were resistant to nalidixic acid. Seventy-two percent were resistant to streptomycin, 45% were resistant to sulfonamides, 28% streptomycin, 45% were resistant to sulfonamides, 28% were resistant to trimethoprim-sulfamethoxazole, and 20% were resistant to trimethoprim-sulfamethoxazole, and 20% were resistant to chloramphenicol. Only 20 strains were were resistant to chloramphenicol. Only 20 strains were isolated throughout the period from 1995 to 1998. All were isolated throughout the period from 1995 to 1998. All were resistant to ampicillin and cephalothin but were susceptible resistant to ampicillin and cephalothin but were susceptible to co-amoxiclav, cefotaxime, gentamicin, and ciprofloxacin. to co-amoxiclav, cefotaxime, gentamicin, and ciprofloxacin. The rate of resistance increased up to 90% for streptomycin The rate of resistance increased up to 90% for streptomycin and sulfonamides, 70% for trimethoprim-sulfamethoxazole, and sulfonamides, 70% for trimethoprim-sulfamethoxazole, 60% for chloramphenicol, and 5% for nalidixic acid(Prats 60% for chloramphenicol, and 5% for nalidixic acid(Prats 2000).” 2000).”

Discussion Discussion

““resistant resistant kelebsiella kelebsiella to gentamycin to gentamycin were isolated from more than one were isolated from more than one body site but the urinary and body site but the urinary and respiratory tract were involved in each respiratory tract were involved in each case(Rennnie 1976).”case(Rennnie 1976).”

““The relative antimicrobial The relative antimicrobial susceptibilities of different susceptibilities of different ShigellaShigella sppspp. may vary geographically (Chu . may vary geographically (Chu 1998).”1998).”

CONCLUSION CONCLUSION

After running this experiment, I will accept my After running this experiment, I will accept my hypothesis because there are different susceptibility hypothesis because there are different susceptibility and resistant to antibiotics in the same family like in and resistant to antibiotics in the same family like in kelebsiella ,yerseniakelebsiella ,yersenia , and , and shigella shigella and they are all in and they are all in the same familythe same family

Ciprofloxacin is the best drug for treatment of diseases Ciprofloxacin is the best drug for treatment of diseases caused by caused by enteriobacteriacaeenteriobacteriacae family but we have to do family but we have to do the antibiotic sensitivity test before giving the drug the antibiotic sensitivity test before giving the drug because peoples in different area develop different because peoples in different area develop different resistance and susceptibility to antibiotics and in my resistance and susceptibility to antibiotics and in my experiment I was dealing with the lab bacteria.experiment I was dealing with the lab bacteria.

The main reason for resistance is the overuse of The main reason for resistance is the overuse of antibiotics especially if people take medicine without antibiotics especially if people take medicine without doing the antibiotic sensitivity test , that will develop doing the antibiotic sensitivity test , that will develop resistance.resistance.

I would like to thank you for your attention

Questions Questions