Bacte Report

8/8/2019 Bacte Report

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Justine Mae R. Gonzales, RMT



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Interaction Between Drug and Host

ySIDE EFFECTS

treatment goes beyond the desired effect

problems that occur in addition to thedesired therapeutic effect



Interaction Between Drug and Host

MAJOR SIDE EFFECTS OF DRUGS:

y A . Toxicity to organs

yB. A llergic responses to drugs

yC. Suppression and alteration of the

microflora by antimicrobials



A . Toxicity to organs HEPATOTOXICITY

chemical-driven liver damageresponsible for 5% of all hospital

admissions and 50% of all acute liver

failures.

KIDNEY TOXICITY

reduced energy output damage to the surface of cells Dehydration death of the tubes used by the kidney to eject wastes

or reabsorb nutrients



B. Allergic responses to drugs

y DRUG ALLERGY are a group of symptoms caused by allergic reaction to a drug

(medication).

Involves antibodies and memory lymphocyte

more likely to develop with large doses and extended exposure

y DRUG INTOLER A NCE/ SENSITIVITY

milder, non-immune-mediated reaction Ex. TINNITUS after a normal dose of aspirin



MOST COMMON DRUG ALLERGIES

yPainkillers (called analgesics) such as codeine, morphine, nonsteroidal anti-

inflammatory drugs (NS A IDs, such as ibuprofen or indomethacin), andaspirin

y A ntibiotics such as penicillin, sulfa drugs, and tetracycline

y A ntiseizure medications such as phenytoin (Dilantin) or carbamazepine (Tegretol)



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SUPERINFECTION

appearance of bacteriological and clinical evidence of new

infection during the chemotherapy of a primary one

Some causative organism of Superinfection:

1. Candida or fungal infection

2. Enterobacteriaceae (Shigella, Salmonella, Escherichia, Klebsiella)

3. Pseudomonas4. Staphylococcus

C. SUPPRESSION AND ALTERATION OF THE

MICROFLORA BY ANTIMICROBIALS



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Considerations in

Selecting an A ntimicrobial Drug



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Considerations in Selecting an Antimicrobial Drug

1. Identify the microorganism causing theinfection.

2. Test the microorganisms susceptibility (sensitivity) to various drugs in vitro

when indicated.3. The overall medical condition of thepatient



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Identifying the Agent

yIdentification of infectious agent

should be attempted as soon aspossible.

ySpecimens should be taken before

antimicrobials are initiated.



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Testing for Drug Susceptibility

yMinimum inhibitory concentration (MIC)

yE-test diffusion

yKirby-Bauer disk diffusion test



Minimum inhibitory concentration

(MIC)smallest concentration of drug that

visibly inhibits growth

a quantitative test to determine the LOWEST

CONCENTRATION of a specific antimicrobial

drug needed to prevent the growth of a given

organism in vitro.



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Minimum bactericidal concentration

(MBC)

Is the lowest concentration of a

specific antimicrobial drug that kills

99.9% of cells of a given strain of

bacteria



E-test diffusion



KIRBY-B AUER DISK DIFFUSION

TEST



KIRBY-B AUER METHOD

known as the disk-diffusion method

determines what treatment of antibiotics

should be used when treating an infection

relies on the inhibition of bacterial growth

measured under standard conditions

Mueller-Hinton agar is used



STANDARDIZ ATION OF THE KIRBY-

B AUER METHOD:

1. Mueller-Hinton agar

must also only be 4mm deep

2. The size of the inoculated organism using barium sulfate standards, McFarland standards

McFarland standards are used as a reference

to adjust the turbidity of bacterial suspensions so

that the number of bacteria will be within a given

range.



PROCEDURE IN KIRBY-B AUER DIFFUSION TEST

1. Using a aseptic technique, place a sterile swab into the brothculture of a specific organism and then gently remove excess

liquid by gently pressing the swab against the inside of the

tube.

2. Using the swab, streak the Mueller-Hinton agar plate. To

obtain uniform growth, streak the plate with the swab in one

direction and then rotate the plate 90° and streak the plate

again in that direction. Repeat the rotation 3 times. Allow the

plate to dry for approximately 5 minutes.

3. Antibiotic discs can be dispensed onto the agar using an Antibiotic Disc Dispenser

4. Using flame-sterilized forceps, gently press each disc to the

agar to ensure that the disc is attached to the agar.

5. Plates should be incubated overnight at an incubation

temperature of 37°.



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The Therapeutic Index

M A RGIN OF S A FETY

Best to chose a drug with HIGHEST LE V EL OFSELECTIVITY BUT LOW EST LE V EL TOXICITY

measured by therapeutic index the ratio of the dose of thedrug that is toxic to humans as compared to its minimumeffective dose

y High index is desirable.

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