Microbiology: A Systems Approach: Chapter 17 Study Guide Flashcards

• Phenotypic
• Genotypic
• Immunological Methods

-identification is based on traits expressed and involve the following subcategories

• Microscopic (gram stain) and Macroscopic (observations of colonies)
• morphology
• Physiological/Biochemical Characteristics (fermentation and enzyme tests like SIM and Carbohydrate Fermentation)
• Chemical Analysis (analysis of chemical composition – such as the cell wall structure)

- Includes genetic analysis

• Polymerase Chain Reaction (PCR)
• G+C composition

-Using the antigen/antibody response to help diagnose infection.

• Agglutination
• Precipitation
• Immunodiffusion
• Complement Fixation
• Fluorescent Antibody tests
• Immunoassay tests

titer

agglutination

precipitation

• hemagglutination – blood
• Coombs test – Rh

patient’s serum, antigen, complement

sheep's blood

no lysis

lysis

syphilis spirochete

serum from patient

fluorescent-labeled anti-human IgG antibody

glowing spirochetes

bead covered with HIV antigen

patient's blood

enzyme linked anti-human antibody

substrate

• staphylococcus - bacterial (Staphylococcus aureus )
• herpes - viral
• varicella - Zoster - viral
• Leishmaniasis - protozoal

• Meningitis
• Rabies
• Toxoplasmosis

• Pneumonia
• Respiratory Syncicial virus
• Influenza
• Hentavirus

• Tularema
• Epstein Barr Virus (mono)
• Malaria

• E. Coli
• Clostridium difficile
• Cryptosporidium

• UTI
• Syphilis
• Trichomonas
• HPV

Coccus, Staph, Gram Positive

Mannitol Salt Agar (salt tolerant and mannitol fermenting) or Blood Agar (Beta hemolysis)

Yellow around growth on MSA; Clear around growth on Blood Agar

1. Bacti-staph – Passive Agglutination test (If it agglutinates, then positive for S. aureus)
2. Coagulase test – using plasma (if it forms clots it is coagulase positive)

1. Herpes Simplex Virus I (HSV-I or cold sores)
2. Herpes Simplex Virus II (HSV-II or Genital Herpes)
3. Varicella-Zoster Virus (HHV-III or Chicken Pox-Shingles)

• All are DNA viruses of the Herpes Family. They are enveloped viruses with an icoshedral capsid.
• The main difference in these viruses are how they are transmitted and the nerves which harbor the latent form of the virus. Lesions are slightly different as well.

• HSVI: Causes cold sores: Transmitted by contact, latent in the trigeminal ganglion nerve which innervates areas of the face, lesions are usually found on the face or around the mouth where the trigeminal nerve comes to the surface of the skin. Can cause up to 30% of neotnatal encephalitis.
• HSVII: Genital Herpes: Sexually transmitted, latent in the sacral ganglia, lesions on internal/external genitalia, thighs, and buttocks.

Varicella-Zoster

1. Pox are an itchy macular lesion that become encrusted and flake off sometimes leaving scars. The lesions start on the face and scalp and spread to the extremities
2. Shingles will erupt due to stress – it causes the virus to become lytic and it travels along the thoracic or trigeminal sensory nerves to the surface of the skin (along the dermatomes) on the back and face. The lesions are more like fluid filled vesicles, very painful and sensitive to touch. Due to inflammation of the nerve – the pain and tenderness can persist for several months

Chicken pox is the first form of the virus. The latent form of the virus is Shingles.

No, you cannot catch shingles, but you can contract chickenpox.

There are vaccines for both Chicken pox and Shingles. The Varicella vaccine is given to children who have not had chicken pox. The Zostavax vaccine is only given to people 60 years or older who have had the chickenpox

• it is
• transmitted through an infected sand fly that bites a host.

The sand fly indigenous to the Middle East, so the disease is found in the Middle East in countries like Iraq, Saudi Arabia, and Afghanistan.

• Prevention involves controlling the sandfly population.
• Treatment is with pentavalent Antimony and pentamidine or Amphotercin B if the organism is resistant to the Antimony alone.

• shift: a large change in the flu virus hemagglutinin spikes. This results from swapping of one RNA segment from a human virus with the RNA from a pig or avian flu virus. This makes the human population vulnerable because it does not have the antibodies and memory cells for this new virus
• drift: what happens each year. Antigens on the Hemagglutinin spike mutate each year

because of antigenic drift

Coccus, Staph, Gram Positive

Mannitol Salt Agar (salt tolerant and mannitol fermenting) or Blood Agar (Beta hemolysis)

Yellow around growth on MSA; Clear around growth on Blood Agar

Bacti-staph – Passive Agglutination test (If it agglutinates, then positive for S. aureus ) Coagulase test – using plasma (if it forms clots it is coagulase positive)

1. Herpes Simplex Virus I (HSV-I),
2. Herpes Simplex Virus II (HSV-II or Genital Herpes),
3. Varicella-Zoster Virus (HHV-III or Chicken Pox- Shingles) and
4. Cytomeglovirus (CMV

All are DNA viruses of the Herpes Family. They are enveloped viruses with an icoshedral capsid

1. Herpes Simplex I – Causes cold sores: Transmitted by contact, latent in the trigeminal ganglion nerve which innervates areas of the face, lesions are usually found on the face or around the mouth where the trigeminal nerve comes to the surface of the skin. Can cause up to 30% of neotnatal encephalitis.
2. Herpes Simplex II – Genital Herpes: Sexually transmitted, latent in the sacral ganglia, lesions on internal/external genitalia, thighs, and buttocks.

Varicella-Zoster

1. Varicella-Zoster: Pox are an itchy macular lesion that become encrusted and flake off sometimes leaving scars. The lesions start on the face and scalp and spread to the extremities.
2. The Zoster (Shingles) virus will erupt due to stress – it causes the virus to become lytic and it travels along the thoracic or trigeminal sensory nerves to the surface of the skin (along the dermatomes) on the back and face. The lesions are more like fluid filled vesicles, very painful and sensitive to touch. Due to inflammation of the nerve – the pain and tenderness can persist for several months. In the shingles along the ophthalmic root of the trigeminal nerve, it can cause an inflammation of the eye and facial paralysis

The sand fly indigenous to the Middle East, so the disease is found in the Middle East in countries like Iraq, Saudi Arabia, and Afghanistan. Therefore, this is a concern for our troops in the Middle East. However, some versions of Leishmaniasis are found in Latin America ( L. mexicana, L. brasiliensis) China and India (L. tropica ).

Prevention involves controlling the sandfly population. A recombinant DNA vaccine is being developed. Treatment is with pentavalent Antimony and pentamidine or Amphotercin B if the organism is resistant to the Antimony alone.

Antigenic shift is a large change in the flu virus hemagglutinin spikes. This results from swapping of one RNA segment from a human virus with the RNA from a pig or avian flu virus. This makes the human population vulnerable because it does not have the antibodies and memory cells for this new virus. Antigenic drift is what happens each year. Antigens on the Hemagglutinin spike mutate each year. This is the reason why a new flu vaccine is needed

• Enterohemoraggic – E. coli O157:H7 (EHEC) – see below
• Enteropathogenic – causes infantile diarrhea (most notably in developing countries – profuse watery diarrhea, fever, vomiting). EPEC causes effacement of gut surfaces like EHEC, similar to EHEC, but does not produce shiga toxin.
• Enterotoxigenic – causes severe diarrhea due to two toxins – heat labile (LT) and stable toxins (ST) as its name suggests. It is a self-limiting illness and is mainly treated with fluid replacement.
• Enteroinvasive – inflammatory diseases similar to Shigella – blood and pus are usually found in the stool with this. However, this bacteria does not produce shiga toxin. Primarily transmitted by contaminated food and water in developing countries, this disease is treated
  with fluid replacement.

Gram negative, Rod-shaped

Bloody diarrhea, fever, sometimes hemolytic uremic syndrome (which leads to kidney failure). The symptoms are due to the shiga toxin (main virulence factor).

Diarrhea illness resulting from the use of broad spectrum antibiotics. The antibiotics can kill bacteria that are sensitive to the antibiotics. Since C. difficile are resistant to the antibiotics, they survive. Then, because they have survived, and there is more room to grow with plenty of nutrients, they will take over the colon.

Prevention – give narrow spectrum antibiotics and handwashing

Cryptosprodium is a protozoal organism that causes a gastrointestinal infection. They are infected by contaminated water.

Diarrhea, vomiting, sweating, and severe abdominal cramping that lasts for 2 weeks.

Normally they treat with chlorine, but many times this is not enough. Therefore filtration along with chlorination have been implemented. It is estimated that 1/3 of fresh water sources in the world have the cysts of cryptosporidium.

Escherichia coli (80%), Staphylococcus saprophyticus (5-10%), and Enterococcus (5-10%) are the causes of UTIs. They are transmitted by accidental contact from fecal matter and due to the small length of the urethra are more common in females than males. General symptoms include pain, itching, and burning upon urination

Treponema pallidum is the causative agent of syphilis. This is a spirochete bacteria.

1. Primary – involves a hard chancre (shang ker) which is evident on the genitalia.
2. Secondary – IF UNTREATED IN THE PRIMARY STAGE - involves a rash on the palms of the hands that spreads all over the body and flu-like symptoms.
3. Tertiary –IF UNTREATED - involves gummas on organs throughout the body (and sometimes on the skin). This can involve the nervous system (neurosyphilis) which can result in personality change, an awkward gait (how they walk), can lead to comma and then death

Since Syphilis is a sexually transmitted disease, abstinence, monogamy, and protection during sex are all ways to prevent Syphilis. Salvarsan (a derivative of atoxyl containing arsenic, which was discovered in the early 1900s by Paul Ehrlich) and Penicillin (available since the 1940s however some are allergic) are treatments for Syphilis. Other antibiotics are also effective but Penicillin is less toxic and still effective if the patient is not allergic.

Trichomonas is a protozoan with flagella.

General symptoms involve a headache, stiff neck, and fever

Viral meningitis is less severe but more common than Bacterial. Luckily, most bacterial meningitis can be treated with antibiotics and most viral meningitis can be fought off by your
immune system.

Rabies virus is a large bullet shaped RNA virus with a helical capsid and envelop; of the Rabdoviridae family

• Furious rabies - Periods of agitation, disorientation, seizures, and twitching. Spasms in the neck and pharyngeal muscles lead to hydrophobia
• Dumb rabies - Patient is not hyperactive but is paralyzed, disoriented, and stuporous

Vaccines are available for occupational exposure to animals that may be rabid. Post-exposure vaccine – 5 intramuscular shots given immediately after exposure includes antibodies against the rabies virus as well as antigens which stimulate the immune response to produce memory cells and antibodies to fight off and prevent
replication of the virus

Because this is a post-exposure vaccine rather than a pre-exposure vaccine, it is a unique vaccine. This preventative/treatment is only possible because the virus is so slow in replicating that there is time to get the vaccine and produce antibodies and memory of the event before it can replicate.

toxoplasma gondii

The signs and symptoms are asymptomatic or marked by mild symptoms such as sore throat, lymph node enlargement, and low-grade fever. In immunocompromised patients and infants, it is often fatal.

Prevention involves hand washing and if pregnant or immunocompromised, having someone else change the cat litter box, or not having a cat.

The most at risk for Toxoplasmosis include babies in the womb and immunocompromised persons.

Rabbit Fever is the common name for Tularemia which is caused by F. tularensis.

Symptoms: headache, backache, fever, chills, malaise, and weakness Further symptoms tied to the portal of entry: ulcerative skin lesions, swollen lymph glands, conjunctival inflammation, sore throat, intestinal disruption, pulmonary involvement

The bacteria are in droplets are formed when skinning the animal. There are multiple portals of entry – Cutaneous infection: skin from tick bite or a cut or scrape; Ophthalmic infection: from droplets that get into the eye; Pulmonary: from breathing in the droplets

Prevention involves waiting until the first hard freeze to hunt small game animals (which should have killed any of the bacteria on small game animals in your area)

Epstein-Barr Virus (EBV) is the most common cause, but Cytomeglovirus (CMV) can cause the disease in immunocompromised hosts (in AIDS patients).

Direct or indirect contact with saliva (kissing, drinking after someone)

Not using the same glass to drink out of, avoiding drinking fountains. Avoid “swapping saliva” with someone with the virus.

1. EBV-depending on health at time of infx, may never know they were infx, mononucleosis, Hodgkin's or Burkett's lymphoma or chronic fatigue syndrome
2. Mono Sx include: sore throat, fever, cervical lymphadenopathy, gray white exudates in throat, rash, enlarged spleen
3. Hodgkin's & Burkett's are blood CAs of lymphocytes

It seems that the more immunocompromised you are when you get the symptoms, the more severe the manifestation of the disease

When viruses penetrate and cause infection, the result can be an acute or persisting infection. Some use the lysogenic method of replication which means they integrate their DNA into the host cell DNA. In integrating their DNA with the host, they either turn on oncogenes (cancer causing genes) or turn off tumor suppressor genes. This is how viruses can cause cancer.

• Plasmodium malariae, P. vivax, P. ovale, and P. falciparum.
• Eukaryotic, Protozoan

1. flu-like Sx that progress to fever and chills
2. female anapholes mosquito
3. controlling mosquito population & bednets
4. quinine, chloroquine, or mefloquine

• S – Syphilis
• T – Toxoplasmosis
• O – Other – including Hepatitis B, AIDS, and Chlamydia
• R – Rubella
• C – Cytomeglovirus
• H – Herpes

These are diseases which can affect the fetus during critical development periods resulting in congenital birth defects, miscarriage, and death