Midterms - MicroPara

8/13/2019 Midterms - MicroPara

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Microbiology and

Parasitology:Midterm Period

Prepared by:

Lucky P. Roaquin, RN, MAN

STC-CON Faculty



Learning Objectives

At the end of the course and given simulated/actual

situations/conditions, the student will be able to:

1. Apply the concepts and principles of microbiologyand parasitology in the care of individuals.

2. Utilize principles and techniques in the collection,

handling of specimens and identification of

microorganisms and parasites involved in theinfectious processes.



Learning Contents

Midterm Period

- Controlling Microbial Growth In Vitro -

- Using Antimicrobial Agents to Control Microbial Growth In Vivo -

- Epidemiology and Public Health -

- Nosocomial Infections & Infection Control -



Controlling Microbial

GrowthIn Vitro



Factors that Affects

Bacterial Growth

• Availability of nutrients

• Moisture

•Temperature

• pH

• Osmotic pressure and salinity

• Barometric pressure

• Gaseous atmosphere



Availability of Nutrients

•

All living organisms require nutrients tosustain life.

• To survive, appropriate nutrients must

be available.• Catabolism and anabolism

• Essential nutrients, elements and trace

elements• About 25 of the 92 naturally occurring

elements are essential to life.



Moisture

• Water is essential to life.

• Cells consist of 70-95% water.

• Water is required to carry out normalmetabolic processes.

• Endospores and cysts can survive

complete drying process (desiccation).



Temperature

• Optimum growth temperature

• Minimum growth temperature

• Maximum growth temperature

•

Thermophiles• Mesophiles

• Psychrophiles

– Psychrotrophs- refrigerator temperature 4°C – Psychroduric organism- can endure freezing

temperature







pH

• Acidity or alkalinity

• Most microorganism prefer a neutral or

slightly alkaline medium (pH 7-7.4)

• Most bacteria grow between pH 6.5 and 7.5

• Molds and yeasts grow between pH 5 and 6

• Acidophi les

• Alkal iphi les

• Vibrio cholerae is the only human pathogenthat grows well above pH 8.



Osmotic Pressure and Salinity

Osmotic pressu re- pressure that is exerted on a cell

membrane by solutions both inside and outside

the cell.

– Osmosis

• Hypertonic

– Crenation

– Plasmolysis

– Desiccation

• Hypotonic

– Hemolysis

– Plasmoptysis

• Isotonic

– Halophilic and haloduric organisms



Plasmolysis



Barometric Pressure

• Most bacteria are not affected by minorchanges in barometric pressure.

• Some thrive at normal atmospheric

pressure (about 14.7 psi).

• Barophi les- thrive deep in the ocean

and in oil wells, where the atmospheric

pressure is high.



Gaseous Atmosphere

•

Oxygen (O2)

Obligateaerobes

Facultativeanaerobes

Obligateanaerobes

Aerotolerantanaerobes

Microaerophiles



Encouraging the Growth of

Microorganism In Vitro

• Gather information in the identification ofany pathogens present.

• Learn more about microorganisms.

• Harvest antibiotics and other microbial

products.

• Test new antimicrobial agents and

produce vaccines.

• Viruses, bacteria, fungi and protozoa,

with emphasis on bacteria.



Culturing Bacteria in the

Laboratory

• petri dishes

• test tubes

• bunsen burners/alcohol lamps

• wire inoculating loops

•

bottles of staining reagents• incubators



Bacterial Growth

Microbial growth = increase in

number of cells, not cell size



Generation Time

• The time it takes for one cell to become twocells by binary fission.

– Rapid growers (short GT)

–

Slow growers (long GT)• E. coli, V. cholerae, Staphylococcus and

Streptococcus- 20 mins.

• Pseudomonas and Clostridium- 10 mins.

• M. tuberculosis- 18 to 24 hours



Culturing Bacteria

• Fast id ious - with complex nutritional

requirements

• Using culture media

• Obligate in tracel lular parasites - do not

grow in culture media

• Treponema pallidum and

Mycobacterium leprae



Culture Media

• Art i f ic ial media or synthet ic media-

they are prepared in the laboratory

• Culture medium - nutrients prepared for

microbial growth

• Inoculat ion- introduction of microbes

into medium

• Culture- microbes growing in/on culture

medium



Classification of Culture Media Based on

Whether the Exact Contents are Known

• Chemical ly def ined media- exact

chemical composition is known

• Complex media- exact contents are not

known, from extracts and digests of

yeasts, meat, or plants



Liquid and Solid Media

•

Liquid media- or broths are containedin tubes, referred to as tubed media.

• Solid media- prepared by adding agar

to liquid media and then poured into testtubes or petri dishes, where the media

solidifies.

– Agar plate

– Agar slant

– Agar but t /deep



Enriched Medium

• Broth or solid medium containing richsupply of special nutrients that promotes

the growth of fastidious organisms.

• Prepared by adding extra nutrients to amedium called nutrient agar.

• Blood agar and chocolate agar

• N. gonorrhoeae and H. influenzae

S l i M di



Selective Medium

• Has added inh ib i tors that discourage the

growth of certain organisms without inhibitinggrowth of the organism being sought.

• MacConkey agar- inhibit growth of Gram (+)

bacteria and is selective for Gram (-) bacteria.

• Phenylethyl alcohol agar (PEA) and

col ist in-nal idix ic acid agar (CNA)- inhibit

growth of Gram (-) bacteria.

• Thayer-Mart in agar and Mart in -Lew is agar-selective for N. gonorrhoeae.

• Mannitol salt agar (MSA)- only for salt-

tolerant (haloduric) bacteria

Diff ti l M di



Differential Medium

• Permits the differentiation of organisms that

grow on the medium.• MacConkey agar- used to differentiate

various Gram (-) bacilli that are isolated from

fecal spcimens.

– Gram (-) bacteria are able to ferment lactose

produces pink colonies, those are unable to

ferment lactose produce colorless colonies.

– Differentiates between LF and NLF Gram (-)

bacteria.

• Mann itol salt agar- used to screen for S.

aureus, pink to yellow.

R b



Remember…

• Various categories of media are not mutually

exclusive.• Ex: blood agar is enriched and differential

• MacConkey agar and MSA are selective and

differential

• PEA and CNA are enriched and selective

• Thayer-Martin and Martin-Lewis are highly

enriched and highly selective

• Thioglycollate broth (THIO) is a liquid

medium that supports the growth of all

categories of bacteria.

I th hi t



In the history…

• Robert Koch - described his culture

techniques in 1881.

• Fanny/Frau Hesse- suggested the use of

agar.

• Richard Ju l ius Petr i - invented the glass

Petri dishes.

• Joseph L ister- the first person to obtain a

pre culture of bacterium (Streptococcuslactis) in a liquid medium.

I l i f C l M di



Inoculation of Culture Media

• Inoculat ion- adding a portion of the

specimen to the medium.

• Inoculaton of a solid or plated medium

involves the use of sterile inoculatingloop to apply a portion of the specimen

to the surface of the medium; a process

commonly referred to as “streaking”.

St ki th A Pl t



Streaking the Agar Plate



Importance of Using

“Sterile Technique”

• Necessary to exclude all microorganisms

from a particular area, so that area will be

sterile.

• Media should remain sterile before

inoculation.

• Contaminants- unwanted microorganisms

• Contaminated- if the sample containscontaminants

I b ti



Incubation

•

After media are inoculated, they must beincubated, and placed in a chamber

(incubator ).

• To culture most human pathogens, the

incubator is set at 35 – 37 o C• Carbon diox ide incubator – 5 to 10%, is

used to isolate capnophiles

•

Non-carbon diox ide incubator –

20 to 21 %of Oxygen

• Anaerobic incubator

B t i l P l ti C t



Bacterial Population Counts

•

Determine the total number of bacterialcells in the liquid

• Determine the number of viable cells

•Spectrophotometer

• Viab le p late coun t

– Is used to determine the number of viable

bacteria in a liquid sample such as milk,water, ground food diluted in water, or broth

culture.



Viable Plate Count



Viable Plate Count

• Number of colonies must be multipliedby the dilution factors.

• If 220 colonies were counted on the

agar plate that had been diluted with a1.0-ml sample of a 1:10,000 dilution,

there were:

• 220 X 10,000= 2,200,000 bacteria/ml

Viable Plate Count



Viable Plate Count

• Plate Counts: Perform serial dilutions of

a sample

Viable Plate Count



Viable Plate Count

• Inoculate Petri

plates from

serial dilutions

Viable Plate Count



Viable Plate Count

• After incubation, count colonies on plates that have

25-250 colonies.

Bacterial Population Growth Curve



Bacterial Population Growth Curve

• Determined by growing a pure culture of

the organism in a liquid medium at a

constant temperature.

• Data are plotted on a graphic paper,

plotting the logarithm (log10) of the

number of viable bacteria (y-axis)

against the incubation time (x-axis).

Bacteria Population Growth Curve



Bacteria Population Growth Curve



Phases of the Growth Curve



Phases of the Growth Curve

• Lag phase- during which the bacteria absorb

nutrients, synthesize enzymes, and preparefor cell division, the bacteria do not increase in

number.

• Log phase- exponential growth phase;

bacteria multiply so rapidly that the number oforganisms double with each generation time.

• Stat ionary phase- the number of bacteria

that are dividing equals the number that are

dying; greatest population density.

• Death/decl ine phase- culture may die

completely





Culturing Obligate Intracellular

Pathogens in the Laboratory

Culturing Fungi in the Laboratory



Culturing Fungi in the Laboratory

• Brain Heart Infu sion Agar

• Sabouraud Dextrose Agar- pH 6.5

selective for fungi

Culturing Protozoa in the



Culturing Protozoa in the

Laboratory

• Acanthamoeba spp.

• Entamoeba hisolytica

• Balamuthia spp.

•

Giardia lamblia• Leishmania spp.

• Trypanosoma cruzi

• Toxoplasma gondii

• Trichomonas vaginalis• Naegleria fowleri

I hibiti th G th f



Inhibiting the Growth of

Microorganism In Vitro

• Sterilization

– Dry heat

– Autoclaving (steam under pressure)

– Gas (ex. ethylene glycol)

– Various chemicals (formaldehyde)

– Radiation (UV, gamma rays)



Disinfection, Pasteurization,

Disinfectants, and Sanitization

• Disinfect ion- removal of pathogens from

nonliving objects by physical or chemical

methods. Ex. Pasteurization

• Disinfectants- are strong chemical

substances that cannot be used on living

tissue.

•Ant iseps is- removal of pathogens from livingtissue

• Sanit izat ion- lower microbial counts on eating

utensils

Microbial Agents



Microbial Agents

• B ioc idal agents / Germ icidal agents / Microb icidal

agents - are disinfectants that kill microbes• Bacter icidal agents- disinfectants that specifically kill

bacteria but not necessarily bacterial endospores.

• Sporic idal agents - to kill bacterial endospores

• Fungicidal agents- to kill fungi, including fungalspores

• A lgicid al agents - to kill algae in swimming pools and

hot tubs.

• Vir icidal agents - destroy viruses• Pseudomon icidal agents- Pseudomonas species

• Tubercu locidal agents- kill M. tuberculosis

Mi bi t ti A t



Microbistatic Agents

• Microbistat ic agent- is drug or

chemical that inhibits growth andreproduction of microorganism

• Bacter iostat ic agents- is one that

specifically inhibits the metabolism andreproduction of bacteria.

• Lyophi l izat ion- is a process that

combines dehydration and freezing. – To preserve foods, antibiotics, anti-sera,

microorganisms

Sepsis Asepsis Aseptic Technique



Sepsis, Asepsis, Aseptic Technique,

Antisepsis, and Antiseptic Technique

• Sepsis- refers to microbial contamination or

presence of pathogens in blood or tissues

• Asepsis- is the absence of significant

contamination.

• Aseptic techniques- prevent microbialcontamination of wounds.

– Hand washing, use of sterile gloves, masks, and

gowns. – Antisepsis : prevention of infection

– Antiseptic Technique- developed by Joseph

Lister, refers to use of antiseptics



• Alternation of membrane permeability

• Damage to proteins

• Damage to nucleic acids

Actions of Microbial Control Agents





• Moist heat-

denaturesproteins

• Autoclave:

– Large pressurecooker

– Steam under

pressure – 15 psi, 121.5C,

20 minutes

Using Physical Methods



• Cold

• Low temperature inhibits microbial

growth

– Refrigeration

– Slow freezing

– Rapid freezing (liquid N)

– Lyophilization (freeze drying)• Desiccat ion

– prevents metabolism

Using Physical Methods

to Inhibit Microbial Growth



•

Radiat ion- damages DNA – Ionizing radiation (X rays, gamma rays,

electron beams)

– Non-ionizing radiation (UV)

– Ultrasonic waves

– Microwaves kill by heat; not especially

antimicrobial





• Filtration



• Gaseous Atmosphere

–

altering the atmosphere in which themicroorganisms are located

– Ex. Gas gangerene



• Chemical disinfection refers to the use of

chemical agents to inhibit the growth of pathogens,

either temporary or permanent.

Using Chemical Agents

to Inhibit Microbial Growth

Factors to Consider Whenever a



Factors to Consider Whenever a

Disinfectant is Used

• prior cleaning

• organic load

• bioburden

• contration of disinfectant

• contact time

• physical nature of the object

• temperature and pH

Characteristics of an Ideal



Characteristics of an Ideal

Microbial Agent

• broad anti-microbial spectrum

• fast acting (short contact time)

• not affected by the presence of organic matter

• non-toxic and non-corrosive

• leave a residual microbial film

• soluble in water and easy to apply

• inexpensive and easy to prepare

• stable, can be stored for long periods

• odorless

How do disinfectant kill



How do disinfectant kill

microorganisms?

• target and destroy cell membranes

(triclosan, detergents, alcohols,

chlorhexidine and phenolic compounds)

• destroy enzyme and structural enzymes

(hydrogen peroxides, formaldehyde, salt

of heavy metals, formaldehyde and

ethylene oxide)

• attack cell wall or nucleic acids

C



• Evaluating a disinfectant

– Use-dilution test

1. Metal rings dipped in test bacteria are dried2. Dried cultures placed in disinfectant for 10

min at 20°C

3. Rings transferred to culture media to

determine whether bacteria survivedtreatment

Using Chemical Agents to Inhibit

Microbial Growth

Using Chemical Agents to



g g

Inhibit Microbial Growth

•

Evaluating a disinfectant• Disk-diffusion method

Chemical Food Preservatives



Chemical Food Preservatives

•

Chemical Food Preservatives – Organic Acids

• Inhibit metabolism

• Sorbic acid, benzoic acid, calcium propionate

• Control molds and bacteria in foods andcosmetics

• Nitrite prevents endospore germination

•Antibiotics- nisin and natamycinprevent spoilage of cheese

Microbial Characteristics and Microbial Control





FurtherQuestion/s



USING ANTIMICROBIAL AGENTS

TO CONTROL MICROBIALGROWTH IN VIVO



WHAT’S THE WORD?

CHEMOTHERAPY

– Use of drug to treat any disease orcondition

– These “drugs” are called

CHEMOTHERAPUETIC AGENT





ANTIBIOTICS

– Antimicrobial substance produced by amicroorganism that is effective in killingor inhibiting the growth of othermicroorganisms.

– Semisynthetic antibiotics – chemicallymodified to kill a wider variety ofpathogens or reduce side effects

Ideal Qualities of an Antimicrobial



Ideal Qualities of an Antimicrobial Agent

Kill or inhibit the growth of pathogens

Cause no damage to the host

Cause no allergic reaction in the host

Stable when stored in solid or liquid form



Remain in specific tissues in the bodylong enough to be effective

Kill the pathogens before they mutateand become resistant to it.



Unfortunately…

Most antimicrobials have:

– Some side effects

– Produce allergic reaction – Permit development of mutant strains

Most Common mechanisms of



Most Common mechanisms of Action of Antimicrobial Agents

Inhibition of cell wall synthesis

Damage to cell membranes

Inhibition of nucleic acid synthesis (DNA or RNA)

Inhibition of protein synthesis

Inhibition of enzyme activity

A tib t i l A t



Antibacterial Agents(Table 9-1)

Inhibition of cell wall synthesis

– Penicillin interferes with the synthesis and

cross-linking of peptidoglycan in Gram(+) like Staphylococcus andStreptococcus



JUST ASKING. . .

WHY DOESN’T PENICILLIN ALSO

DESTROY HUMAN CELLS?



COMPETITIVE INHIBITION

– Sulfonamide molecule is similar in shape to PABA(para-amino benzaldehyde)

– PABA is converted to folic acid which is essentialin the synthesis of some bacterial proteins

– If there is no conversion of PABA to folic acid toessential proteins, the bacterial cell will

eventually die

– Sulfa drugs are BACTERIOSTATIC AGENTS



JUST ASKING. . .

WILL HUMAN CELLS BE AFFECTED BY

SULFA DRUGS?



WHAT’S THE WORD?

NARROW - SPECTRUM ANTIBIOTICS

– Destroys only Gram (+) bacteria Vancomycin

– Destroys only Gram (-) bacteria Colistin and Nalidixic acid



BROAD - SPECTRUM ANTIBIOTICS

– Destructive to both Gram (+) andGram (-) bacteria

Ampicillin

Chloramphenicol

Tetracycline



SOMETHING TO REMEMBER

Antimicrobial agents work well againstbacterial pathogens because the bacteria(being procaryotic) have different cellularstructures and metabolic pathways that canbe disrupted or destroyed by drugs that donot damage the eucaryotic host’s cell.



MULTIDRUG THERAPY

Two or ore drugs are used simultaneouslyto kill all the pathogens and to preventresistant mutant strains from emerging.

– Four drugs used in M. tuberculosae infection

Isoniazid

Rifampin Pyrazinamide

Ethambutol or Streptomycin

Synergism VS Antagonism



Synergism VS Antagonism

SYNERGISM

– Two antimicrobial agents are used totreat an infectious disease a greaterdegree (effect) than that achieved byeither drug alone.

Trimethoprim + Sulfamethoxazole =

Co-trimoxazole (Bactrim and Septra)



ANTAGONISM

– Two drugs working against each other – The extent of pathogen killing is less than

that achieved by either drug alone.



ANTIFUNGAL AGENTS

How do they work ?

Binding with cell membrane sterols

– (nystatin, amphotericin B)

Interfere with sterol synthesis – (clotrimazole and miconazole)

Blocks mitosis or nucleic acid synthesis – (griseofulvin and 5-flucytosine)



ANTIPROTOZOAL AGENTS

How do they work ?

Interfere with DNA and RNA synthesis – (chloroquine, pentamidine,quinacrine)

Interfere with protozoal metabolism – (metronidazole – Flagyl)



ANTIVIRAL AGENTS

ZIDOVUDINE (AZT)

– First antiviral drug effective against HIV

(1987) – “Coctails” (1990’s) a combination of

antiviral drugs



SUPERBUGS

Microorganisms that have become

resistant to one or more antimicrobialagents.



MRSA (Methicillin-resistant S. aureus)

MRSE (Methicillin-resistant S. epidermidis)

VISA (Vancomycin-Intermediate S. aureus)

VRSA (Vancomycin-Resistant S. aureus)-verycommon in nosocomial infection

VRE (Vancomycin – Resistant Enterococcus spp.)

MRTB (Multidrug-Resistant M. tuberculosis)

How can Bacteria Become



How can Bacteria BecomeResistant to Drugs

INTRINSIC RESISTANCE

– Lack specific target site for the drug(Mycoplama – cellwalless)

– Drug cannot cross the bacterial cell wallor cell membrane



ACQUIRED RESISTANCE

– Alteration of drug- binding sites due tochromosomal mutation

– Alteration of the structure of the cellmebrane



– Ability of organism to produce enzymesthat destroys the drug (R-factor is passedon to other bacteria via conjugation)

– Ability to develop Multidrug- Resistancepumps (MDR transporters)-pumps drug

out of the cell before it causes damage



BETA-LACTAMASES

B-lactam ring – the heart of Penicillinand Cephalosporin structures

If B-lactam is destroyed, the antibioticno longer works

Two types of B-lactamases:



Two types of B-lactamases:

Penicillinases – destroys the B- lactamrings of Penicillins

Cephalosporinases – destroys the B-lactam ring of Cephalosporins



Combination of Drugs to Combat theEffect of B-lactamases:

– Clavulinic acid + Amoxicillin = Augmentin

– Clavulinic acid + Tiracarcillin = Timentin

– Sulbactam + Ampicillin = Unasyn – Tazobactam + Piperacillin = Zosyn



EMPIRIC THERAPY

Clinicians initiate therapy beforelaboratory results are available.

Based on an “educated guess” basedon prior knowledge/ experiences with

the particular type of infectiousdisease the patient has.



Factors to consider. . .

Laboratory result of pathogen’sidentity – refer to “pocket chart”.

Is patient allergic to anyantimicrobials?

Age of the patient?

Is patient pregnant? In-patient or out-patient?



Availability of the drug

What is the site of infection?

Medications received by the patient. Other medical problems?

Is patient immunocompromised?

Cost of the drug?

id ff



Side Effects. . .

Allergies

Toxicity (Chloramphenicol – aplasticanemia)

Superinfection (opportunists and secondaryinvaders overgrowth)

– Antibiotic Associated Diarrhea (AAD) and

Pseudomembranous Colotis (PMC) caused by C.difficile

– Candida albicans infection

Closure / Carry Over



Closure / Carry Over Activity

What Can Clinicians, ParamedicalProfessionals and Patients Do To Help in theWar Against Drug Resistance? (pp154-155)

– Editorial Cartoon

– Poster

– Slogan

– Jingle – Radio Advertisement

– Poem





1976



1976

Legionnaires’ Disease

– severe form of pneumonia, characterizedby headache, chest pain, lung congestion,and high fever. The name is derived froman outbreak at an American Legion

convention in a Philadelphia hotel in July1976.

1992 1993



1992 - 1993

Escherichia coli O157

– A food-borne disease caused by a particularvariant of the common intestinal bacteriumE. coli . Although E. coli is normally present inthe human intestines, the variant E. coliO157:H7 produces toxins that cause bloodydiarrhea and, in some cases, far more severeproblems, including kidney failure and death. Aperson can become infected by eatingcontaminated meat. Thorough cooking kills thebacteria.

1993



1993

Hantaviruses are carried by specificrodent hosts and are transmitted directlyfrom host to host by virus-laden saliva,urine, and feces.

Humans are infected through exposure tothe dried excretions from infected rodents.Hantaviruses cause two different human

diseases: hemorrhagic fever with renalsyndrome, in which damage to the kidneysis common, and acute respiratory distresssyndrome, in which damage to the lungs iscommon.

1993



1993

Cryptosporidiosis

– A diarrheal disease which resulted fromdrinking water that was contaminatedwith Cryptospridium parvum

2002



2002

West Nile Virus

– infectious organism that can cause fatal

neurological disease in birds, horses, andhumans. The virus is transmitted by the bite ofan infected mosquito. West Nile virus is namedfor a district in Uganda where the virus was firstidentified in humans in 1937.

– As the virus spread, U.S. public health officialsworked with local communities to track thespread of the virus and to control mosquitopopulations to prevent virus transmission.

WHAT’S THE WORD?



WHAT’S THE WORD?

EPIDEMIOLOGY

– The study of disease, basically thefactors that determine the following:

Frequency

Distribution

Determinants in human population



Q ti k d b EPIDEMIOLOGISTS



Questions asked by EPIDEMIOLOGISTS:

What pathogens are causing the infection?

Where do the pathogens come from?

When do certain diseases occur Why do some diseases occur in some places

but not in others

How are pathogens transmitted?

Do some diseases occur only at certain timeof the year? If so, why?

TERMINOLOGIES



TERMINOLOGIES

COMMUNICABLE DISEASE

– Transmission : person to person



CONTAGIOUS

– Communicable disease that is easilytransmitted from one person to another







PANDEMIC DISEASES

– A disease occurring worldwide HIV / AIDS (pp.179 – 180)

Tuberculosis (p. 180)

Malaria (p. 180)

Interactions Among Pathogens, Hosts



g g ,and the Environment

FACTORS AFFECTING THE OCCURRENCEOF INFECTIOUS DISEASES



Pertaining to the Pathogen

Virulence Portal of Entry

Number of organisms



Pertaining to the Host

Health status Nutritional status

Socioeconomic, hygiene,

travel,immune status, substance abuse



Pertaining to the Environment

Physical factors – Location,

– climate,

– heat,

– cold,

– humidity,

– season of the year



Availability of appropriate reservoir

Sanitary and housing conditions,adequate waste disposals

Availability of potable water

SIX COMPONENTS IN THE INFECTIOUSDISEASE PROCESS



DISEASE PROCESS(CHAIN OF INFECTION)

Presence of a pathogen

Source of the pathogen (reservoir)

Portal of exit Mode of transmission

Portal of entry

Susceptible host

FIVE PRINCIPAL MODES OF



TRANSMISSION

Contact (direct or indirect)

Airborne

Droplet Vehicular

Vectors

Communicable diseases are transmittedfrom person to person in the following



from person to person in the followingways:

Direct Skin-to-Skin Contact

– Handshake

Direct Mucous membrane –Mucousmembrane Contact

– Kissing – Sexual intercourse



Indirectly by airborne droplets

– Sneezing

– Coughing

Indirectly by contamination of food

and water by fecal material



Indirectly by arthropod vectors – Mosquitoes

– Flies

– Fleas

Indirectly by Fomites

– Stethoscope – Gloves



Indirectly by transfusion of blood orblood products

– Syringes

– Needles



FurtherQuestion/s



HEALTHCARE EPIDEMIOLOGY:

NOSOCOMIAL INFECTIONS AND

INFECTION CONTROL

HEALTHCARE EPIDEMIOLOGY



HEALTHCARE EPIDEMIOLOGY

- “Any activity designed to study and / orimprove patient care outcomes in any typeof healthcare institution or setting.”

- Includes a variety of disciplines andactivities directed at enhancing the qualityof healthcare and preventing and controlling

adverse outcomes.(SHEA)

What is the importance of MICROBIOLOGY toh h l h f i l ?



the healthcare professionals?

Whether they are working in a hospital,

nursing home, medical or dental clinic,or caring for a sick person they MUST

follow standardized procedures toprevent the spread of communicable

diseases.

TWO TYPES OF INFECTIOUS DISEASES(INFECTIONS)



(INFECTIONS)

Hospital acquired (Nosocomial)

– Includes those that erupt within 14 daysof hospital discharged

Acquired outside the healthcare

facilities (Community-acquired)



Iatrogenic Infections

– “physician – induced”

– Result of medical or surgical treatment(surgeons, physicians,healthcarepersonnel)

– Examples: post - surgical woundinfections and urinary tract infections(catheterization)





Urinary catheters provide a “superhighway” for indigenous normal

flora to access the urinary bladder

70% of nosocomial infections involved

drug – resistant bacteria

HARD TO TREAT NOSOCOMIAL AGENTS



O OSOCO G S

Pseudomaonas infections

MRTB

VRE

MRSA

MRSE

Others (developed drug-resistant)

– HIV – Candida spp.

– Malarial parasites

MOST COMMON TYPES OF NOSOCOMIALINFECTIONS



INFECTIONS

1. Urinary Tract Infections

2. Surgical Wound Infections

3. Lower Respiratory Tract Infections4. Bloodstream Infections



Nosocomial Infection of the GIT iscommonly caused by Clostridium difficile

– Produces enterotoxin and cytotoxin

– AAD (Antibiotic- Associated Diarrhea)-enterotoxin

– PMC (Pseudomembranous Colitis) - cytotoxin

MOST VULNERABLE PATIENTS INHOSPITAL SETTINGS



HOSPITAL SETTINGS

Elderly patients Women in labor and delivery Premature infants and newborns Surgical and burn patients Diabetic and cancer patients Patients receiving treatment with steroids,

anticancer drugs, anti-lymphocyte serum

and radiation Immunosuppressed patients Patients who are paralyzed and undergoing

renal dialysis or catheterization

MAJOR FACTORS CONTRIBUTING TONOSOCOMIAL INFECTIONS



NOSOCOMIAL INFECTIONS

Increasing number of drug – resistantpathogens

Failure of personnel to follow infectioncontrol guidelines

Increased number of

immunocompromised patients

OTHER FACTORS



Indiscriminate use of antimicrobial agents

False sense of security about antimicrobial

agents

Lengthy, more complicated type of surgery

Overcrowding of hospitals, shortages ofstaff





TWELVE STEPS TO PREVENT

ANTIMICROBIAL RESISTANCE AMONG HOSPITALIZED ADULTS



WHAT CAN BE DONE TO REDUCE

THE NUMBER OF NOSOCOMIALINFECTIONS?



WASH HANDS BEFORE YOU . . .

WASH HANDS AFTER YOU. . .

WASH HANDS IN THE FOLLOWINGMANNER. . .



Roughly 1/3 of adults seem to haveforgotten one of the most basic lessonstheir mothers taught them: wash yourhands properly. Although 95% of people say

that they scrub after using public toilets,researchers from the American Society ofMicrobiology found that only 67 % actuallydo.

PROPER HANDWASHING-It is better tobe safe, than to be sorry.



TWO TYPES OF ASEPSIS



MEDICAL ASEPSIS

– “clean technique” involves proceduresand practices that reduce the number andtransmission of pathogens

Hand washing

Personal grooming

Proper cleaning of supplies and equipments

Disinfection



SURGICAL ASEPSIS

– “sterile technique”

– practices use to keep objects and areassterile

Scrubbing hands and fingernails Sterile gloves , masks, gowns, shoe cover

Using sterile solutions and dressing













STANDARD PRECAUTIONS

FORINFECTION CONTROL

WORD TO PONDER. . .



All healthcare workers MUST fullycomprehend the problem of

nosocomial infections, MUST becompletely knowledgeable about

infection control practices, and MUST personally do everything in their

power to prevent nosocomialinfections from occurring.

CARRY – OVER - ACTIVITY



Interview doctors and paramedicalpractitioners of the effective waysemployed in the hospital to reduce

nosocomial infections.

Date post:	04-Jun-2018
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Midterms - MicroPara

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