Effect Of Vancomycin And Kanamycin On Ecoli Biology Essay

This diary evaluates the combined actions of two antibiotic drugs, Vancomycin and Kanamycin on log phase civilization of E.coli and Staph aureus was carried out. Other groups besides worked on two other 1s, Ampicillin and Cefsoludine. The check was carried out to happen out if their actions will be interactive, counter, habit-forming or independent. The MIC and MBC of the combined drugs was determined in this check and FBCs and FICs were calculated. Some were found to be interactive while others were either counter or habit-forming.

Modern medical specialty is dependent on chemotherapeutic agents, chemical agents that are used to handle diseases. Chemotherapeutic agents destroy infective micro-organisms or suppress their growing at concentrations low plenty to avoid unwanted harm to the host. Most of these antibiotics, microbic merchandises or their derived functions can kill susceptible micro-organisms or suppress their growing ( Rang et al. , 2003 ) .

We will write a custom essay sample on
Effect Of Vancomycin And Kanamycin On Ecoli Biology Essay
or any similar topic only for you
Order now

Effectiveness of drugs varies therefore doing some of them either narrow-spectrum drugs or wide spectrum drugs. An thought of their effectivity can be obtained from minimum repressive concentration ( Dawson et al. , 2004 ) . Minimal repressive concentration ( MIC ) is the lowest concentration of a drug that prevents growing of a peculiar pathogen ( Underwood, 2007 ) . The minimum deadly concentration ( MLC ) is the lowest drug concentration ( Dawson et al. , 2004 ) .

The intent of this reappraisal was to find the MIC and MBC of drug combinations.


Antibiotics A and B of concentrations 500 and 250µg/ml-1 were severally used. A was Vancomycin while B was Kanamycin. Along with log stage civilizations of Staph. Aureus, E.coli, microtitre trays, pipettes, stop ticker.

Consecutive dilutions of drugs were prepared into the microlitre home base. Then 100ul of alimentary stock was dispensed into each well of the microtitre tray, followed with the add-on of 100µl of first antibiotic to each well in column 1, therefore halving antibiotic concentration. With fresh pipette tip, 100µl was transferred from each well in column 1 into matching next good in column 2. The duplicating dilution was continued across the home base until column 11 was reached. From each well in column 11, 100ul was removed and discarded off. The first antibiotic was non put in column 12.

Following this was add-on of 100ml of the 2nd antibiotic to each row A. The antibiotic was added to well A12 and worked back across the home base to well A1 understating the hazard of reassigning the first antibiotic from a well of higher concentration to a lower one.

Now the 2nd antibiotic concentration is halved, doing a farther concentration of the first antibiotics in this row being halved. Further transportation of 100ul with a fresh pipette tip was made from each well in row A to the matching good in row B. This was repeated get downing with good A12 and worked back across the home base to good A1 was reached.

Dilution doubling was carried on down the home base every bit far as row G. Repeated was flinging of 100µl from each well in row G doing certain that no 2nd antibiotic was added to row H Wellss get downing from H12, assorted and 100ul was so discard. Row H wells antibiotic is stand foring by row H while column 12 is for the 2nd antibiotics. The positive growing control is good H12 which has no antibiotic in it. With fresh pipette tip, E.coli suspension was added to each well in the home base and worked backwards along the rows from column 12 as above. All Wellss were assorted good throughout the experiment


Microtitre tray was left base for 30 proceedingss during which 12 food agar home bases were each divided into 8 sections and labelled them 1A,1B,1C……1H etc. 10µl bead was taken from each well and placed in the labeled section on one of the home bases.

Tray and home bases were incubated at 37oC


After incubation, Wellss were examined for any bacterial growing and recorded as ( + ) to bespeak growing and ( – ) if there was no growing. Using the consequences in row H for first antibiotic and column 12 for 2nd antibiotic, MIC and MBC were calculated, reading the lowest concentration where there is no bacterial growing. A well was identified in another row and recorded as MIC.

Fractional Inhibitory Concentrations ( FIC ) was calculated for E.coli as:

FIC = Concn of antibiotic1 in this well + Concn of antibiotic2 in this well

MIC of antibiotic1 MIC of antibiotic2

A = Vancomycin 4000µg/ml

B = Kanomycin 250µg/ml

C = Ampicillin 500µg/ml

D = Cetsulodin 125µg/ml

FIC = Concn of antibiotic1 in this well + Concn of antibiotic2 in this well

MIC of antibiotic1 MIC of antibiotic2

MIC A = 1000µg/ml-1 MIC B = 15.63

FIC ( E4 ) = 125 + 7.81 = 0.125 + 0.5 = 0.625

1000 15.63

FIC ( D5 ) = 250 + 7.81 = 0.25 + 0.5 = 0.750


The value obtained for FIC is between ( 0.5 – 1 ) , which indicates additivity of the FIC.

E.coli grew in all concentrations of Kanomycin therefore could n’t work out the MBC and FBC in it.

Antibiotic A has a minimal bacterial 1000µg/ml while Antibiotic B is non disinfectant.

Fractional Inhibitory Concentrations ( FIC ) was calculated for Staph.aureus as:

FIC = Concn of antibiotic1 in this well + Concn of antibiotic2 in this well

MIC of antibiotic1 MIC of antibiotic2

MIC 1 = 12D ( 31.25 ) MIC 2 = H2 ( 1000 )

FIC ( 7F ) = 31.91 + 31.25 = 0.25 + 0.03 = 0.28

15.63 1000

FIC ( 11D ) = 15.63 + 1.95 = 1 + 0.00195 = 1.002

15.63 1000

The value obtained for FIC is & A ; lt ; 0.5 which indicates synergism and the other value obtained is between 1 and 2 which indicates liberty

3H, minimal bacterium of Staph.aureus MBC for kanomycin for its bactericidal,

Can non be worked for FBC in this experiment because Vancomycin is stronger ( strong bactericidal ) suppressing the growing of Staph.


An FI ( B ) C of & A ; lt ; 0.5 indicates synergis and & A ; gt ; 2 indicates antagonism.Autonomy ( 1-2 ) or additivity ( 0.5 – 1 ) . From the deliberate consequences, MBC for Vancomycin was 62.5µg/ml and for kanamycin is125µg/ml. That Kantrex doubled that of Vancomycin. While for MIC, Vancomycin 31.25µg/ml doubled that of Kanamycin.

The lowest repressive fraction of MICs obtained by the microtitre combination of Vancocin and kamamycin is 1:16. The ratio for the consequences once more E.coli of 1:32 and that against S.aureus is 1.128. The FIC calculated against E.coli and S.areus was & A ; gt ; 0.5.

The combination of the 2 drugs Vancomycin and Kamamycin can be saib to be interactive. Other groups used 2 other drugs C, Ampicillin concentration 500µg/ml and D, Cefsoludine concentration = 125µg/ml

Comparative consequences shows action of the drugs B+D to be interactive where the FIC is 0.16 and FBC, 0.75 for S.aureus while for same drugs B + D, for E.coli it was found to be linear with FIC as 0.6. Another drug combination of A+B shows counter action at high concentration of FIC as 18 while low with FIC of 0.38. There has been a broad scope of different consequences from other compared groups.


Hi there, would you like to get such a paper? How about receiving a customized one? Check it out