The Antibiotic Sensitivity Test Presented by Marian Mikhail

The Antibiotic Sensitivity Test Presented by Marian Mikhail Undergraduate student Biology Major Health and Science Concentration Tennessee Tech University Cookeville, Tennessee 38505

Introduction n Problem: susceptibly or resistance of bacteria to antibiotics n “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). ” n n

Introduction n n “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 n n “Prevention monitoring program has detected the first U. S. case of Shigella infection resistant to the fluoroquinolone (moon 2003). ” “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 -1970 s, 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 10 mg TE-tetracycline 30 mg CIP-ciprofloxacin 5 mg GM-gentamycin 10 mg Bacteria used in the experiment Escherichia coli , Escherichia coli O 157: H 7, Shigella boydii Shigella sonnei, Yesinia enterocolitica Kelebsilla pneumoniae, Providencia stuartii, Morganella morganii Salmonella typhumurium, salmonella typhi

Results o o o 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 O 157: H 7 17/S 18/I 29/S 15/S 3 -Shigella boydii 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 32/S 13/I 8 -Morganella 0/R 21/S 40/S 17/S 9 -Salmonella tyhi 17/S 32/S 19/S 10 -Salmonella 25/S typhimurium 17/I 35/S 17/S

n Statistics of the zone of inhibition of this family: mean = =786/40=19. 65 mm

Results 1 -E-coli 2 - E-coli O 157: H 7 3 -shigella boydii 4 -shigella sonnei 5 -yersinia 6 -Kelebsilla 7 -Providencia 8 -Morganella 9 -Salmonella Tyhi 10 -Salmonella typhimurium

DICUSSION n n “ 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 n “All pathogenic Yersinia enterocolitica strains isolated in our laboratory belonged to serogroup O 3 (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 n n “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 n n n 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