Controlling the Growth of Bacteria

Controllingthe Growth of Bacteria

TheEffect of Ampicillin (AM, the Disc Potency (10 μg)), on E.coli, Staphylococcus aureus and Enterococcus faecalisPathogens.

Bacteriaare identified to be single celled organisms, which do not have anucleus. They are biologically known to be nearly all over the Earth,in a variety of species, which directly and indirectly, get to bebeneficial when relating to other existing organisms, within theenvironment (Kroghet. al., 2005).As part of their function, bacteria get to be necessary in theoptimum maintenance of the environmental system, surrounding plantsand animals. This should bring the understanding that health getsaffected by these organisms if not well monitored. Their implicationsmay vary in scale, if economically measured, through the medicationprocess (Kroghet. al., 2005).

Escherichiacoli(E. coli) bacteria are harmless bacteria, which exist in varieties.They cause relatively epigrammatic diarrhea as they subsist inhealthy people and animals intestines (Krogh,2005). They have the potential to cause abdominal cramps, which aresevere, vomiting bloody and diarrhea. To identify Salmonella,itis a Gram-negative and toxic pathogenic bacteria mostly found in theintestinal lumen. Due to its outer membrane, that largely consistingof lipopolysaccharides it becomes toxic, therefore needs to beprotect from the environment.

Staphylococcusaureus,commonly found on human skin and in respiratory tract of humans, is aGrampositive coccalbacteria and a Firmicute’smember (Dickey, 2003). Although it not pathogenicalways, it commonly causes respiratory diseases, skin infections andfoodpoisoning.Then the Streptococcuspneumoniaknown to be Gram-positiveand of genusStreptococcusmembership, is a pathogenicbacterium,significant in humans, as a key pneumoniacause.

Thereis need to control the bacterium, with the use of Ampicillin. This iswith the reason that, it is an antibioticthat is practical in treating a number of bacterialinfections, based on the fact that it is of the aminopenicillinfamily and a beta-lactamantibiotic.Further it is vigorous against numerous Gram(-)and Gram(+)bacteria, as a betalactamaseinhibiting drug (Giles and Eloise, 2011, 2008, 2005).

IfAmpicillin (AM, the Disc Potency (10 μg) ) is used to inhibitStaphyloccocus aureas and Enteroccocus faecalis , which aregram-positive, inhibition gets to be better that in E. coli, whichis gram-negative bacterium.

Theefficiency is because of its sensitivity to toxicity, as compared tosome chemical factor demonstration, which permits one beta lactamantibiotic to inhibit in E. coli. Bacteria sensitivity is understoodto be the susceptibility of the bacteria to an antibiotic, a chemicalused to inhibit its effects. Therefore, the Î ¼g unit, used is anabbreviation of lactam antibiotic portion used to inhibit a pathogen.

IfAmpicillin (AM, the Disc Potency (10 μg) is applied in inhibitionof E.coli gram-negativebacteria, then the sensitivity zone area of its inhibition will beless as compared to the sensitivity zone area of Enterococcusfaecalisand Staphylococcusaureas,which are gram-positive pathogens.&nbspThe reason behind such anoutcome is because of E.colipathogen sensitivity zone area, which is less, alongside its gramnegative factor.

Ampicillinis a beta-lactam antibiotic and of aminopenicillin family. Basedon its features, it effectively inhibits the chosen bacterium types,studied under gram stained slides.

Picture1: An observation of the Gram stained slide

Focusingon this fact, the control of bacteria gets to be inevitable, withagents to control, the fungi and bacteria growth getting to bedeveloped, known as antibiotics. An antibiotic is identified to be achemical that is produced by a fungus or bacterium, with the abilityto control another fungus or bacteria growth. The antibiotic may beselective in some cases in inhibiting bacteria and fungi effect.

Duringthe investigation conducted, fungi and bacteria growth control agentswere put to test to determine their efficacy. The agents ranged fromantiseptics, antibiotics and disinfectants of Ampicillin(AM, the Disc Potency (10 μg)).

Thetest was based on the hypothesis that pathogenic bacteria causes’disease in plants and animals, and given agents, could be used incontrolling them. Three different viruses of E.coli, Enterococcus faecalisand Staphylococcusaureus,were used in the control experiment, for the sake of justifying theefficacy of Ampicillin (AM, the Disc Potency (10 μg)), through alaboratory test.

Materialsand Methodology

Ensuringthe success of the experiment, materials and procedures to use wereprerequisites (Gunstream, 2008). The acquisition of Tryptic soyagarplate, sterile swab, parafilm strips, wax pencil, antibiotic disks,antibiotic dispenser and metric ruler was important, alongside abacteria lawn identified as broth cultures of Salmonellatyphimurium, E. coli, Staphylococcus aureus andStreptococcuspneumonia (Cappuccinoand Natalie, 2011).

Theexperiment was conducted in a laboratory in a systematicmethodological manner to ensure that a proper preparation of thebacteria lawn had been conducted(Cappuccino and Natalie, 2011).Labeling of the Tryptic soy agar plate was done at the bottom, withan appropriate name, initials, laboratory number, and date of theexperiment and the indication name of the experiment, to show that itwas an antibiotic (Cappuccino and Natalie, 2011). Then, the bacteriallawn was prepared through inserting of a sterile swab in the cultureof bacteria in a liquid full of nutrient broth. The swab was thenallowed to drip for a minute, and then was taken out of the tube forculturing, soaked and not dripping, and without squeezing of the tip.

Thereafter,the Tryptic soy agar plate lid was lifted and application of the lawndone on the Tryptic soy agar plate surface. This was through ensuringthe rotation of the plates and swabbing them at the appropriateangles while the initial application was being done. Then the lid gotclosed and the Tryptic soy agar plate that was swabbed with thebacteria carried to the demonstration table.

Afterwards,the plate lid was removed and the antibiotic disk dispenser placedover the plate, then the disks got dispensed. All the disks weresaturated with a given antibiotic indicated on them, in a symbol(Gunstream, 2009). The lid was then replaced and the plate inverted,then initially placed in the incubator for 24 hours under 37 degreesCelsius and then refrigerated at 4º C, for 144 hours, equivalent to6 days.

Aftera week, the cultures were examined, as a way to determine theirantibiotic sensitivity. The determination was through measuring thediameter of the inhabitation zone, which was the area surrounding thedisk of inhibition of the bacterial growth (Gunstream, 2012). Themeasurements of the bacteria were recorded alongside each antibiotic.


Afterall this procedural and methodological process, bacteria sensitivitywas determined, through scaling it from those not sensitive,sensitive to very sensitive, through the observing of theirantibiotic sensitivity. The not sensitive, was identified to be theno zone of inhibition, with the sensitive zone being the zone sizeabove 0 mm but below 10 mm(Gunstream,2008).The very sensitive zone was the zone above 10 mm.

Theresults generated out of the procedural experimentation process wereas noted in the table below. The findings were then graphed and theoutcome picture recorded. This validated the hypothesis as they wereconsidered to be tangible facts, thoroughly, experimented under aprocedural scientific process.


E. Coli

Enterococcus Fa

Staphylococcus A


Standard Deviation




































E. Coli

Enterococcus Fa

Staphylococcus A







Table1: Experimentation data results of samples pathogens

Graph1: Pathogen sensitivity results of Vardui and Standard Deviation

Picture2: Labeled Tryptic soy agar with pathogen samples

Indetermining the sensitivity of Ampicillin(AM, the Disc Potency (10 μg)), E.coli, Staphylococcus aureus andEntertococcusFa, weretested alongside the determination of Control.E. coli, Staphylococcus aureus andEntertococcusFa, hada high sensitivity considered very sensitive since the score theygenerated was above 10 mm. Hence, for all the bacteria, the zone ofinhibition was the same. This was seen to support the hypothesis.Extensively, in the control, Ampicillinwas at 6 mm considered to be sensitive, as it lay in the inhibitionzone of 0 – 10 mm.

Basedon the results, it was inevitable that, in the case ofE. coli, Ampicillinwith 13.4 mm would be applicable, with the case of Staphylococcusaureus,Ampicillin with 28.9 mm being used andfinally EntertococcusFa,Ampicillin with 15.3 mm being used. This was with the initialconsideration that the three had fallen in the very sensitive zonethat was greater than 10 mm therefore, considered effective.

Avariance was, however noted in the gram negative (–) and positive(+). The difference noted was that, E.coli, that had Ampicillinwith 13.4 mm had gram – , with the case of Staphylococcus aureus,thathad Ampicillin with 28.9 mm having gram +, EntertococcusFa,withAmpicillin with 15,3 mm had gram + with the control exhibiting noparticular gram charge.

Asan alternative thought on the variance in effectiveness of theantibiotics, the fact that brings about the basis that, some fungiand bacteria, chemical components vary in inhibiting the effect ofsome pathogens gets to be validated. This has all to do with thefigurative variance in the sensitivity zone variations, as a matterof fact, creating effectiveness and suitability of which chemical toapply on which pathogen with respect to the potential environmentalsystem safeguard.

Discussionand Conclusion

Justlike any other experimentation process, interpretation of results iscritical in the desire to draw applicable conclusions(Gunstream,2012).The findings get to assist in prescribing of both to existingproblematic facts and in the advancement of knowledge as a potentialavenue for solutions in the future of research(Gunstream,2009).Through the pathogenic experimental study, it was evident that, somechemical components from some fungi and bacteria could inhibit theeffect of given fungi and bacteria that exist in an environment andthose that tend to pose a threat to plant and animal health.

Therefore,it was evident that the sensitivity of Ampicillin(AM, the Disc Potency (10 μg)), onE.coli, Staphylococcus aureus andEntertococcusFa,waseffective in the inhibition of the pathogen(,2005). This was through the test done on them. However, in thecontrol part of it, the score got to be sensitive, as it could suitthe application at all levels. It is therefore factual that, E.coli, Staphylococcus aureus andEntertococcusFa, hada high sensitivity considered very sensitive in the sensitivity zonescale since the score generated was above 10 mm. Having a bacteriazone of inhibition being the same,Ampicillin (AM, the Disc Potency (10 μg)), suits the inhibitionprocess(Giles et. al., 2005). Ampicillin use in inhibition of gram-positiveStaphyloccocusaureasand Enteroccocusfaecalis,is effective, as to E.coli,which is gram-negative.

Asa matter of fact to verify the appropriateness of the antibiotic, theresults, brought out the inevitability that, in the case ofE. coli, Ampicillinhad a sensitivity zone area of 13.4 mm making it applicable in thatparticular pathogen. Additionally, in the case of Staphylococcusaureus,Ampicillin with 28.9 mm yielded an appealing result in therestriction of the pathogenandfinally verifying the EntertococcusFa pathogen,Ampicillin with a sensitivity zone are of 15.3 mm succeeded in theexperiment. The success of the three was strongly supported by thescientific test that verified that they fell in the sensitive zone,which was greater than 10 mm, making a consideration that theantibiotic was effective.

Thevariance in gram charge, of either being negative (–) or evenpositive (+) could have determined to some level, the antibiotic’seffectiveness (Dickey, 2003). The noted difference was that, E.coli, that had Ampicillinwith 13.4 mm had gram –this might have favoredits success in inhibiting the pathogen, a case that might have beendifferent if the gram charge was to be +. In the case ofStaphylococcusaureus,Ampicillin had a sensitivity zone area of 28.9 mm with gram +,an equivalent observation in gram charge to EntertococcusFa,with Ampicillin having a sensitivity zone area of 15.3 mm. The gram +might have facilitated the success of the antibiotic, in ensuringattainment of a very sensitive zone area attainment in the strata.

Inconclusion, it is evident that, various fungi and bacteria, chemicalcomponents react differently on different pathogens, revealed throughthis experiment. The effectiveness could be as a matter of gram – oreven +, sensitivity zone area and even the concentration level of theinhibiting agent. The figurative variance fact creates effectivenessand suitability in the determination of which chemical to apply in agiven pathogenic infection that might have an effect on plants andanimals, alongside referencing and prescribing therapies, that mightbe applied in related infections. Therefore, it is important to useAmpicillin, which is of the family and a beta-lactamantibiotic,hence an effective antibiotic, as observed from the predictions.


CappuccinoJ., and Natalie S. (2011). Microbiology:A laboratory Manual.9ThEd.

Dickey.,J.(2003).LaboratoryInvestigations for Biology.2NdEd.

GilesJ., and Eloise M. (2011. 2008, 2005). InvestigatingBiology Laboratory Manual.7Th Ed.

Gunstream.,S.(2008).Explorationsin Basic Biology.11ThEd.

Gunstrea.,S. (2009). BiologicalExplorations: A Human Approach.6ThEd.

Gunstream.,S. (2012). Explorationsin Basic Biology.12ThEd.

Krogh.,D. R. and Kristen., E. (2005). Laboratory Guide to Natural World. 2NdEd.