Infection Control- Chap 18- COMPLETED/INCLUDES TERMS

For test

Bacilli

Rod shaped bacteria

(can cause tuberculosis and other diseases)

Fungi

Organisms, such as mushrooms, yeasts, and molds found on the land. Candida is a common yeast found in the oral cavity

aerobes

bacteria that requires oxygen to grow

anaerobes

bacteria that grows in the absence of oxygen but are destroyed by oxygen

chancre

(Pronunciation: Cain-Keer)

a painless ulcerating sore

cocci

spherical bacterial cells that reproduce by dividing into two

Creutzfeldt-Jakob disease

rare chronic brain disease with onset in middle to late life (40 - 60 years)

Ebola

rare, deadly virus that causes bleeding inside and outside the body

endospores (spore)

resistant, dormant structures formed inside of some bacteria that can withstand adverse conditions

Facultative anaerobes

organisms that can grow with or without oxygen

gram negative

classification of bacteria that does not hold a dye stain under a microscope

gram positive

classification of bacteria that holds a dye stain and appears dark purple under a microscope

gram’s stain

four step staining process developed by Hans Christian Gram, used to separate bacteria into groups

gram variable

classification of bacteria that sometimes stain

H1N1 (Swine Flu)

form of swine influenza A virus

herpesvirus

virus that causes infections in humans, such as herpes, chicken pox, shingles, etc

HPV

the most common STD in the united states, causing genital warts and cancer.

Latent

dormant

microbiology

study of microorganisms

microcephaly

abnormal smallness of the head, a congenital condition associated with incomplete brain development

methicillin resistant staphylococcus aureus (MRSA)

type of infection that is resistant to some antibiotics

nonpathogenic

microorganisms that do not produce diseases

oral candidiasis

candida yeast infection of the oral mucosa.

a white membranes on the surface of the oral mucosa, tongue, and elsewhere in the oral cavity.

Lesions may look like thin cottage cheese and can be wiped off to reveal a raw, red, and sometimes bleeding base

pathogens

disease producing microorganisms

percutaneous

through the skin, such as a needle stick, a cut, or a human bite

petri plate

a small flat dish made of thin glass or plastic that contain a sterile solid medium for the culture of organisms, also called a petri dish

prions

infectious partials of protein that lack nucleic acids (does NOT contain DNA or RNA)

protozoa

A large group of single-celled organisms.

Most do not cause disease but some live inside their host and can cause damage.

A small number are responsible for intestinal infections in human beings; others invade the blood, lungs, liver, or brain

provirus

virus that is hidden during the latency period

spirochetes

spiral shaped bacteria

staphylococci

cocci that form irregular group or clusters

streptococci

cocci that form chains as they divide

tyndallization (fractional sterilization)

intermittent, or factual, sterilization

virulent

capable of causing serious disease

viruses

ultramicroscopic infectious agent that replicates inside living cells

Zika

a virus that is spread to people primarily through the bite of an infected Aedes species mosquito

HBV

a virus necessary for cornification with HDV

Rickettsia

Short, nonmoveable rods.

lives in the intestinal tract of insects such as lice, fleas, ticks, and mosquitoes.

They are very small and require host cells to reproduce.

Diseases caused by Rickettsia include typhus and Rocky Mountain spotted fever. Transmitted to humans by way of the bite of an infected insect.

Algae

From microscopic single-cell to larger multiple-cell organisms such as seaweed and kelp.

Contain chlorophyll, as well as pigments that cause them to appear yellow-green, brown, or red.

Algae are found in abundance in both freshwater and marine habitats.

Most algae do not produce human disease.

Virus Latency

 Some viruses establish a dormant state in host cells

can be reactivated in the future and produce more infective viral particles, followed by signs and symptoms of the disease

Stress, another viral infection, and exposure to ultraviolet light can reactivate the virus

HIV has a latency period of months to years

Hepatitis C is known to have a latency period of 15 to 25 years

What does symptomatically mean?

Treating the symptoms, not the infective cause

Are viruses capable of mutation

Yes

Viruses can cause

Many diseases in humans

Why can’t we create a super vaccine?

It is very difficult to develop vaccines against viruses because of the ability of viruses to change their genetic code

Why are general antibiotics ineffective against viruses

General antibiotics are ineffective in preventing or curtailing viral infections, and even the few drugs that are effective against some specific viruses have limitations

 Viral diseases are transmitted by

*Direct contact

*Insects

*Blood transfusions

*Contaminated food or water

*Inhalation of droplets expelled by coughing or sneezing

What are the 5 types of viral hepatitis

◦Hepatitis A virus (HAV)

◦Hepatitis B virus (HBV)

◦Hepatitis C virus (HCV)

◦Hepatitis D virus (HDV)

◦Hepatitis E virus (HEV)

HAV

*Spread from person to person when someone has HAV (fecal-oral transmission)

 *Good hygiene and proper sanitation can also help prevent hepatitis A

 *Always wash your hands after changing a diaper or using the bathroom

 *The least serious form of viral hepatitis

 *Vaccine is available that provides long-term prevention in persons older than 2 years

HBV

 A very serious disease that may result in prolonged illness, liver cancer, cirrhosis of the liver, liver failure, and even death

 *Bloodborne disease that may also be transmitted by other body fluids, including saliva

 *Anyone who has ever had the disease, and exposed but have not been actually ill, may be carriers of —- and may actually be spreading the infection to others

 *High risk for dental personnel because dental treatment brings them into contact with saliva and blood

 *Highly effective vaccine is available to prevent —

 *All dental personnel with a chance of occupational exposure should be vaccinated against —

 *The OSHA requires that the employer offer the —- vaccination, at no cost to the employee, within 10 days of initial assignment

HCV

 *Most efficiently transmitted through blood

◦Can occur from infected needles

 *Carrier rate for HCV is higher than that of HBV

 *No vaccine against hepatitis C and nor is there a cure for the disease

*Treatments available to control effects of the disease

HDV

 *A defective virus that cannot replicate itself without the presence of HBV

 *Vaccination against HBV also prevents infection with HDV

HEV

 *Not transmitted through blood contact

 *Most frequently transmitted through contaminated food or water (fecal-oral)

 *HEV is most frequently seen in the form of an epidemic in developing countries

*Transmission is not a major concern in a standard dental setting

HIV is a

bloodborne viral disease

 *Infection in which the body’s immune system breaks down; AIDS is caused by HIV

 *A person with HIV infection may remain healthy for many years

 *AIDS is considered to develop in an HIV-positive person when he or she becomes sick with serious illnesses and infections that can occur with HIV

 *HIV is spread by sexual contact with an infected person and through needle sharing among drug users

◦Blood is screened for HIV antibodies, the blood supply in this country is safe

 *Babies born to HIV-infected mothers may become infected before or during birth or, after birth, while breastfeeding

 *In (nondental) healthcare settings, workers have been infected with HIV after being stuck with needles containing HIV-infected blood

Herpesvirus

 Double-stranded DNA virus that causes infection in humans

 May be dormant for years and may become activated and cause disease

 Four major types

◦Herpes simplex virus (HSV)

◦Herpes simplex virus type 1 (HSV 1)

◦Herpes simplex virus type 2 (HSV 2)

◦Herpes zoster virus (HZV)

◦Cytomegalovirus (CMV)

◦Epstein-Barr virus (EBV)

Herpes Simplex Virus Type 1

 *A viral infection that causes recurrent sores on the lips

 *Because these sores frequently develop when the patient has a cold or fever,commonly known as fever blisters or cold sores

Primary Herpes

 highly contagious, makes its first appearance in very young children (1 to 3 years of age)

Recurrent Herpes Labialis

 *After the initial childhood infection, the HSV lies dormant and reappears later in life as the familiar recurring fever blister or cold sore

 Recurrences tend to take place when resistance is lowered due to stress, fever, illness, injury, or exposure to the sun

Herpes Simplex Virus Type 2

 *Genital herpes is one of the most common sexually transmitted diseases in the US

 Initial symptoms (generally appear 2 to 10 days after infection); tingling, itching, and a burning sensation during urination

 *Herpes zoster virus

◦Causes both varicella (chickenpox) and herpes zoster (shingles)

◦Chickenpox is the primary infection, and zoster represents reactivation of the illness

 Cytomegalovirus(CMV)

◦Can affect the fetus during pregnancy

 Epstein-Barr virus

Responsible for infectious mononucleosis, nasopharyngeal carcinoma, lymphoma, and oral hairy leukoplakia

Herpes Transmission

Happens through direct contact with lesions

No active lesions?, there is still the transmission through saliva or aerosol spray from the dental handpiece

there is no preventive vaccine against herpes

Protective eyewear is important because a herpes infection in the eye may cause blindness

Gloves protect against infection through lesions or abrasions on the hands

Ebola virus

Rare but often deadly virus

Causes bleeding inside and outside of the body

First occurred in 1976

Disease kills up to 90% of people who are affected

Spread through direct contact with blood and body fluids

A person infected with Ebola is not considered contagious until symptoms appear

Zika Virus

Spread to people primarily through the bite of an infected mosquito

symptoms include fever, rash, joint pain, and conjunctivitis

People do not usually get sick enough to go to the hospital; very rarely die

Can be spread from pregnant woman to fetus, which has been linked to a serious birth defect called microcephaly

Bacterial Diseases

 *Tuberculosis

 *Legionnaires’ disease

 *Tetanus

 *Syphilis

 *Methicillin-resistant Staphylococcus aureus (MRSA)

Tuberculosis

 Caused by the bacterium Mycobacterium tuberculosis

 Leading cause of death resulting from infectious disease worldwide

 HIV and tuberculosis are often present together

◦Of the two diseases, tuberculosis is a greater health risk for healthcare workers

 “Tuberculosis kill time” is the benchmark for the effectiveness of a surface disinfectant

Legionnaires’ Disease

causes two acute bacterial diseases

◦Pontiac fever

◦Legionnaires’ disease

 Transmitted through aerosolization and aspiration of contaminated water

 (No person-to-person transmission)

Tetanus

 *Known as lockjaw

 *An extremely dangerous/fatal disease caused by a spore-forming bacillus found in soil, dust, or animal or human feces

 *introduced into the body through a wound or break in the skin (e.g., a puncture wound caused by a soiled instrument)

*The disease can be prevented by the administration of a vaccine; however, immunity must be kept current through booster doses

Syphilis

STD

First stage of syphilis is a painless ulcerating sore, known as a chancre, which is infectious on contact

Second stage is also infectious; immediate infection may occur as a result of contact with an open sore

The third stage, known as latent syphilis, is usually fatal, and it may occur after the disease has been dormant for 20 years

Methicillin-Resistant Staphylococcus aureus (MRSA)

A bacteria that is resistant to some antibiotics

This has evolved due to the excessive use of penicillin antibiotics over the years

The infection can be on the surface of the skin or can go into the soft tissue and form a boil or an abscess

Prevention Tips for MRSA (Staph Infection)

 *Always maintain good hand hygiene practices

 *Never squeeze or try to drain any sore

 *Keep any wound covered until it has healed

 *Do not share personal items such as towels, razors, sheets, clothes

what does microbiology mean?

Micro means “microscopically small,” and bio means “living organisms

 The two major oral diseases are bacterial infections

◦Dental caries (decay)

◦Periodontitis

Aristotle believed what?

 Believed that life arose from muck, decaying food, warm rain, or even dirty shirts, and that life was “spontaneously generated”.

John Tyndall did what?

Explained the need for prolonged heating to destroy microorganisms.

 Joseph Lister recognized what?

Recognized the role of airborne microorganisms in postsurgical infections

Louis Pasteur is/developed/disproved what?

He is the “Father of microbiology,”

developed the process of pasteurization and discovered the first vaccine for rabies.

Also disproved the theory of spontaneous generation of life.

Robert Koch is/developed

German scientist, who developed a two-part dish (with his assistant julius petri) that is used to grow bacteria and a techniques to isolate pure colonies of bacteria.

Koch’s Postulates Guidelines:
(Proved that specific microorganisms caused a particular disease)

 1.The microbial agent must be found in every case of the disease

 2.The microorganism must be isolated and grown in pure culture

 3.The microorganism must cause the same disease when inoculated into a susceptible animal

 4.The same microbial agent must be recovered from the inoculated animal

Koch’s guidelines are still used today to determine the microbial agent, how it grows and the disease.

Major Groups of Microorganisms

 1. Bacteria

 2. Rickettsiae

 3. Algae

 4. Protozoa

 5. Fungi

 6. Prions

 7. Viruses(only can be viewed by a powerful microscope)

Bacteria

are large groups of one-celled microorganisms that vary in shape, size, and arrangements

Pathogenic Bacteria

usually grows best in 98.6°F (37°C) in a moist, dark environment

Normal Flora

harmless bacteria on skin, lungs, gut

 Hans Christian Gram developed what?

developed a four-step staining process for separating bacteria into two groups

Three types of Gram

Gram positive

Gram negative

Gram variable

Capsules

protective layer that covers the cell wall of bacteria(e.g., Streptococcus mutans)

◦Generally virulent (capable of causing serious disease)

increases the bacteria’s ability to resist the defense mechanisms of the body

◦may also prevent antibiotic agents from having an effect on the bacteria

Human prion diseases affect which of the following tissues?

Brain and Spinal cord

Which chemical is capable of destroying viruses in an external environment?

alcohols, bleach, hydrogen peroxide, peracetic acid, phenolics, glutaraldehyde, and iodophors